Jeffrey S. Glenn, M.D., Ph.D.
Joseph D. Grant Professor and Professor of Microbiology and Immunology
Medicine - Gastroenterology & Hepatology
Bio
Dr. Glenn's primary interest is in molecular virology, with a strong emphasis on translating this knowledge into novel antiviral therapies. Current projects aim to better understand the role of prenylation in the life cycles of hepatitis delta virus (HDV) and other viruses--both as a mechanism of intracellular trafficking and trigger of virus assembly, and as a target for a promising antiviral treatment. The function and cell biology of hepatitis and respiratory virus proteins are also being studied, with a focus on identifying key determinants of pathogenesis and designing novel antiviral strategies for hepatitis, influenza, and enteroviruses. Of particular interest are targets in host cells upon which viruses depend, and critical RNA secondary structures in viruses. Other interests include exploitation of hepatic stem cells, development of small animal models, NASH, liver cancer, and engineered human liver tissues.
Clinical Focus
- Gastroenterology
Academic Appointments
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Professor, Medicine - Gastroenterology & Hepatology
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Professor, Microbiology & Immunology
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Member, Bio-X
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Faculty Fellow, Sarafan ChEM-H
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Member, Stanford Cancer Institute
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Member, Wu Tsai Neurosciences Institute
Administrative Appointments
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Director, ViRx@Stanford--Stanford Biosecurity and Pandemic Preparedness Initiative (2021 - Present)
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Director, Center for Hepatitis and Liver Tissue Engineering (2006 - Present)
Honors & Awards
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Translational Research Award, American Liver Foundation/Amgen/AASLD (1998-2002)
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Regents Scholarship, U.C.S.F. (1984-1993)
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Elected member, American Society for Clinical Investigation (2008)
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Clinical Scientist Award in Translational Research, Burroughs Wellcome Fund (2005-2010)
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Career Award, Burroughs Wellcome Fund (1998-2005)
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Physician Postdoctoral Fellowship Award, Howard Hughes Medical Institute (1995-1998)
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Summa cum laude, U.C. Berkeley (1984)
Professional Education
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Fellowship: Stanford University Division of Gastroenterology and Hepatology (1998) CA
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Board Certification: American Board of Internal Medicine, Gastroenterology (2018)
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Residency: Stanford University Internal Medicine Residency (1995) CA
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Medical Education: University of California at San Francisco School of Medicine (1993) CA
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Ph.D., U.C.S.F., Biochemistry and Biophysics (1992)
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M.D., U.C.S.F., Medicine/MSTP (1993)
Current Research and Scholarly Interests
Dr. Glenn's primary interest is in molecular virology, with a strong emphasis on translating this knowledge into novel antiviral therapies. Current projects aim to better understand the role of prenylation in the life cycles of hepatitis delta virus (HDV) and other viruses--both as a mechanism of intracellular trafficking and trigger of virus assembly, and as a target for a promising antiviral treatment. The function and cell biology of hepatitis and respiratory virus proteins are also being studied, with a focus on identifying key determinants of pathogenesis and designing novel antiviral strategies for hepatitis, influenza, and enteroviruses. Of particular interest are targets in host cells upon which viruses depend, and critical RNA secondary structures in viruses. Other interests include exploitation of hepatic stem cells, development of small animal models, NASH, liver cancer, and engineered human liver tissues.
2024-25 Courses
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Independent Studies (10)
- Directed Investigation
BIOE 392 (Aut, Win, Spr, Sum) - Directed Reading in Medicine
MED 299 (Aut, Win, Spr, Sum) - Directed Reading in Microbiology and Immunology
MI 299 (Aut, Win, Spr, Sum) - Early Clinical Experience in Medicine
MED 280 (Aut, Win, Spr, Sum) - Graduate Research
MED 399 (Aut, Win, Spr, Sum) - Graduate Research
MI 399 (Aut, Win, Spr, Sum) - Medical Scholars Research
MED 370 (Aut, Win, Spr, Sum) - Medical Scholars Research
MI 370 (Aut, Win, Spr, Sum) - Undergraduate Research
MED 199 (Aut, Win, Spr, Sum) - Undergraduate Research
MI 199 (Aut, Win, Spr, Sum)
- Directed Investigation
Graduate and Fellowship Programs
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Gastroenterology & Hepatology (Fellowship Program)
All Publications
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Pegylated Interferon Lambda for Covid-19. Reply.
The New England journal of medicine
2023; 388 (22): 2108
View details for DOI 10.1056/NEJMc2303519
View details for PubMedID 37256990
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Treatment of chronic hepatitis d with peginterferon lambda - the phase 2 LIMT-1 clinical trial.
Hepatology (Baltimore, Md.)
2023
Abstract
Chronic Hepatitis Delta Virus (HDV) infection leads to the most aggressive form of human viral hepatitis for which there is no FDA-approved therapy. PEG IFN-lambda-1a (Lambda) has previously demonstrated a good tolerability profile in HBV and HCV patients compared to PEG IFN-alfa. The goal of the Phase 2 LIMT-1 trial was to evaluate the safety and efficacy of Lambda monotherapy in patients with HDV.Open-label study of Lambda 120 or 180 mcg, administered once weekly by subcutaneous injections for 48 weeks followed by 24 weeks of post-treatment follow-up.33 patients were allocated to Lambda 180 mcg (n=14) or 120 mcg (n=19). Baseline mean values: HDV RNA 4.1 log10 IU/mL (SD±1.4); ALT 106 IU/L (35-364) and bilirubin 0.5 mg/dL (0.2-1.2). Intention to treat rates of virologic response to Lambda 180 mcg and 120 mcg , 24 weeks following treatment cessation were 5 of 14(36%) and 3 of 19 (16%), respectively. Post treatment response rate of 50% was seen in low BL viral load (≤4 log10) on 180 mcg. Common on-treatment AEs included flu-like symptoms and elevated transaminase levels. Eight (24%) cases of hyperbilirubinemia with or without liver enzyme elevation, leading to drug discontinuation were mainly observed in the Pakistani cohort. The clinical course was uneventful, and all responded favorably to dose reduction or discontinuation.Treatment with Lambda in patients with chronic HDV may result in virologic response during and following treatment cessation. Clinical phase 3 development of Lambda for this rare and serious disease is ongoing.
View details for DOI 10.1097/HEP.0000000000000309
View details for PubMedID 36800850
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Early Treatment with Pegylated Interferon Lambda for Covid-19.
The New England journal of medicine
2023; 388 (6): 518-528
Abstract
The efficacy of a single dose of pegylated interferon lambda in preventing clinical events among outpatients with acute symptomatic coronavirus disease 2019 (Covid-19) is unclear.We conducted a randomized, controlled, adaptive platform trial involving predominantly vaccinated adults with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in Brazil and Canada. Outpatients who presented with an acute clinical condition consistent with Covid-19 within 7 days after the onset of symptoms received either pegylated interferon lambda (single subcutaneous injection, 180 μg) or placebo (single injection or oral). The primary composite outcome was hospitalization (or transfer to a tertiary hospital) or an emergency department visit (observation for >6 hours) due to Covid-19 within 28 days after randomization.A total of 933 patients were assigned to receive pegylated interferon lambda (2 were subsequently excluded owing to protocol deviations) and 1018 were assigned to receive placebo. Overall, 83% of the patients had been vaccinated, and during the trial, multiple SARS-CoV-2 variants had emerged. A total of 25 of 931 patients (2.7%) in the interferon group had a primary-outcome event, as compared with 57 of 1018 (5.6%) in the placebo group, a difference of 51% (relative risk, 0.49; 95% Bayesian credible interval, 0.30 to 0.76; posterior probability of superiority to placebo, >99.9%). Results were generally consistent in analyses of secondary outcomes, including time to hospitalization for Covid-19 (hazard ratio, 0.57; 95% Bayesian credible interval, 0.33 to 0.95) and Covid-19-related hospitalization or death (hazard ratio, 0.59; 95% Bayesian credible interval, 0.35 to 0.97). The effects were consistent across dominant variants and independent of vaccination status. Among patients with a high viral load at baseline, those who received pegylated interferon lambda had lower viral loads by day 7 than those who received placebo. The incidence of adverse events was similar in the two groups.Among predominantly vaccinated outpatients with Covid-19, the incidence of hospitalization or an emergency department visit (observation for >6 hours) was significantly lower among those who received a single dose of pegylated interferon lambda than among those who received placebo. (Funded by FastGrants and others; TOGETHER ClinicalTrials.gov number, NCT04727424.).
View details for DOI 10.1056/NEJMoa2209760
View details for PubMedID 36780676
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Programmable Antivirals and Just-in-Time Vaccines: Biosecurity Implications of Viral RNA Secondary Structure Targeting.
Health security
2022
View details for DOI 10.1089/hs.2022.0098
View details for PubMedID 36576394
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FUNCTIONAL CURE WITH LONAFARNIB-BASED THERAPY IN CHRONIC HEPATITIS DELTA
WILEY. 2022: S297-S298
View details for Web of Science ID 000870796601004
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Modeling the Interplay between HDV and HBV in Chronic HDV/HBV Patients
MATHEMATICS
2022; 10 (20)
View details for DOI 10.3390/math10203917
View details for Web of Science ID 000873101500001
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ESTIMATING HEPATITIS DELTA PREVALENCE AMONG HIGH RISK POPULATIONS IN THE UNITED STATES: A SYSTEMATIC REVIEW
WILEY. 2022: S254-S255
View details for Web of Science ID 000870796600299
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ESTIMATING THE PREVALENCE OF CHRONIC HEPATITIS B AMONG FOREIGN-BORN PERSONS LIVING IN CANADA BY COUNTRY OF ORIGIN
WILEY. 2022: S261-S262
View details for Web of Science ID 000870796600308
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Programmable antivirals to target conserved essential shapes in pandemic viral genomes
NATURE MEDICINE
2022
View details for DOI 10.1038/s41591-022-01910-3
View details for Web of Science ID 000844603700002
View details for PubMedID 36008723
View details for PubMedCentralID PMC9406275
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Programmable antivirals targeting critical conserved viral RNA secondary structures from influenza A virus and SARS-CoV-2.
Nature medicine
2022
Abstract
Influenza A virus's (IAV's) frequent genetic changes challenge vaccine strategies and engender resistance to current drugs. We sought to identify conserved and essential RNA secondary structures within IAV's genome that are predicted to have greater constraints on mutation in response to therapeutic targeting. We identified and genetically validated an RNA structure (packaging stem-loop 2 (PSL2)) that mediates in vitro packaging and in vivo disease and is conserved across all known IAV isolates. A PSL2-targeting locked nucleic acid (LNA), administered 3d after, or 14d before, a lethal IAV inoculum provided 100% survival in mice, led to the development of strong immunity to rechallenge with a tenfold lethal inoculum, evaded attempts to select for resistance and retained full potency against neuraminidase inhibitor-resistant virus. Use of an analogous approach to target SARS-CoV-2, prophylactic administration of LNAs specific for highly conserved RNA structures in the viral genome, protected hamsters from efficient transmission of the SARS-CoV-2 USA_WA1/2020 variant. These findings highlight the potential applicability of this approach to any virus of interest via a process we term 'programmable antivirals', with implications for antiviral prophylaxis and post-exposure therapy.
View details for DOI 10.1038/s41591-022-01908-x
View details for PubMedID 35982307
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Lonafarnib combination with peginterferon Lambda diminished triphasic HDV kinetic pattrn seen under Lambda monotherapy: the LIFT HDV study
ELSEVIER. 2022: S70-S71
View details for Web of Science ID 000826275100113
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Mathematical modeling of HDV RNA kinetics suggests high peginterferon Lambda efficacy in blocking viral production: insights from the LIMT-1 study
ELSEVIER. 2022: S859
View details for Web of Science ID 000826275104256
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Estimating the prevalence of hepatitis delta infection among foreign-born adults with chronic hepatitis B in the United States
ELSEVIER. 2022: S274
View details for Web of Science ID 000826275101297
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First-in-human experience using RBS2418, an oral ENPP1 inhibitor within an expanded access protocol in combination with pembrolizumab in a patient with metastatic adrenal cancer.
LIPPINCOTT WILLIAMS & WILKINS. 2022
View details for Web of Science ID 000863680302822
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Combination of Novel Therapies for HDV.
Viruses
2022; 14 (2)
Abstract
Treatment options for HDV have been limited to interferon alfa-based therapies with its poor efficacy to side effects ratio. Several novel therapies have now advanced into the clinic. As they each have a different mechanism of action, there is the potential for combination therapy. Here we review how studying the HDV life cycle has led to the development of these novel therapies, the key developments leading to, and the details of, the first combination study of novel anti-HDV therapies, and suggest what additional combinations of novel therapies can be anticipated as we enter this exciting new area of HDV treatments.
View details for DOI 10.3390/v14020268
View details for PubMedID 35215860
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Efficacy and Safety of a Botanical Formula Fuzheng Huayu for Hepatic Fibrosis in Patients with CHC: Results of a Phase 2 Clinical Trial.
Evidence-based complementary and alternative medicine : eCAM
2022; 2022: 4494099
Abstract
Background: Hepatitis C virus (HCV) is a common cause of progressive hepatic fibrosis, cirrhosis, and hepatocellular carcinoma worldwide. Despite the availability of effective direct-acting antivirals, patients often have significant hepatic fibrosis at the time of diagnosis due to delay in diagnosis and comorbidities which promote fibrogenesis. Thus, antifibrotic agents represent an attractive adjunctive therapy. Fuzheng Huayu (FZHY), a traditional Chinese medicine botanical formulation, has been used as an antifibrotic agent in chronic HBV infection. Our aim was to assess FZHY in patients with HCV infection and active viremia.Method: We randomized 118 patients with active viremia from 8 liver centers in the U.S. to receive oral FZHY (n=59) or placebo (n=59) for 48 weeks. Efficacy was assessed by histopathologic changes at the end of therapy. A subset of biopsies was further analyzed using qFibrosis to detect subtle changes in fibrosis in different zones of the hepatic lobules.Results: FZHY was well tolerated and safe. Patients with baseline Ishak fibrosis stages F3 and F4 had better response rates to FZHY than patients with baseline F0-F2 (p=0.03). qFibrosis zonal analysis showed significant improvement in fibrosis in all zones in patients with regression of the fibrosis stage.Conclusions: FZHY produced antifibrotic effects in patients with baseline Ishak F3 and F4 fibrosis stages. Reduction in fibrosis severity was zonal and correlated with the severity of inflammation. Based on its tolerability, safety, and efficacy, FZHY should be further investigated as a therapy in chronic liver diseases because of its dual anti-inflammatory and antiibrotic properties. Lay Summary. This is the first US-based, multicenter and placebo-controlled clinical trial that shows statistically significant reduction in fibrosis in patients with active HCV using an antifibrotic botanical formula. This has important implications as there is an immediate need for effective antifibrotic agents in treating many chronic diseases including NASH that lead to scarring of the liver. With artificial intelligence-based methodology, qFibrosis, we may provide a more reliable way to assess the FZHY as a therapy in chronic liver diseases because of its dual anti-inflammatory and antifibrotic properties.
View details for DOI 10.1155/2022/4494099
View details for PubMedID 35873630
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A Phase ii dose finding study of lonafarnib and ritonavir with or without interferon alpha for chronic delta hepatitis.
Hepatology (Baltimore, Md.)
2021
Abstract
BACKGROUND & AIMS: Proof-of-concept studies demonstrated lonafarnib (LNF), a first-in-class, oral prenylation inhibitor, efficacy in HDV-infected patients. The LOnafarnib With Ritonavir for HDV-2 (LOWR-2) study's aim was to identify optimal combination regimens of lonafarnib + ritonavir (RTV) ± pegylated interferon alfa (PEG-IFNalpha) with efficacy and tolerability for longer term dosing. Here we report the safety and efficacy at end of treatment (EOT) for up to 24 weeks.APPROACH & RESULTS: 55 patients with chronic HDV were consecutively enrolled in an open-label single-center phase 2 dose-finding study. There were 3 main treatment groups: high dose lonafarnib (lonafarnib ≥ 75 mg po bid + ritonavir) (N=19, 12 wks); all-oral low dose lonafarnib (lonafarnib 25 or 50 mg po bid + ritonavir) (N=24, 24 wks) and combination low dose lonafarnib with PEG-IFNalpha (lonafarnib 25 or 50 mg po bid + ritonavir + PEG-IFNalpha) (N=12, 24 wks). The primary endpoint, ≥ 2 log10 decline or < LLOQ of HDV-RNA from baseline at EOT, was reached in 46% (6/13) and 89% (8/9) of patients receiving the all-oral regimen of lonafarnib 50 mg bid + ritonavir, and combination regimens of lonafarnib (25 or 50 mg bid) + ritonavir + PEG-IFNalpha, respectively. In addition, multiple patients experienced well-tolerated transient post-treatment ALT increases resulting in HDV RNA negativity and ALT normalization. The proportions of grade 2 and 3 GI adverse events in the high vs low dose groups were 49% (37/76) and only 22% (18/81), respectively.CONCLUSIONS: Lonafarnib, boosted with low dose ritonavir, is a promising all-oral therapy, and maximal efficacy achieved with PEG-IFNalpha addition. The identified optimal regimens support the first Phase 3 (D-LIVR) study of lonafarnib for the treatment of HDV.
View details for DOI 10.1002/hep.32259
View details for PubMedID 34860418
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Hepatitis Delta Virus Testing and Research.
Gastroenterology & hepatology
2021; 17 (10): 482-484
View details for PubMedID 35462727
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HEPATITIS D VIRUS INFECTION IN UNITED STATES WOMEN WITH OR AT RISK FOR HIV
WILEY. 2021: 422A
View details for Web of Science ID 000707188002104
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Cryo-EM and antisense targeting of the 28-kDa frameshift stimulation element from the SARS-CoV-2 RNA genome.
Nature structural & molecular biology
2021
Abstract
Drug discovery campaigns against COVID-19 are beginning to target the SARS-CoV-2 RNA genome. The highly conserved frameshift stimulation element (FSE), required for balanced expression of viral proteins, is a particularly attractive SARS-CoV-2 RNA target. Here we present a 6.9A resolution cryo-EM structure of the FSE (88nucleotides, ~28kDa), validated through an RNA nanostructure tagging method. The tertiary structure presents a topologically complex fold in which the 5' end is threaded through a ring formed inside a three-stem pseudoknot. Guided by this structure, we develop antisense oligonucleotides that impair FSE function in frameshifting assays and knock down SARS-CoV-2 virus replication in A549-ACE2 cells at 100nM concentration.
View details for DOI 10.1038/s41594-021-00653-y
View details for PubMedID 34426697
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Addiction to Golgi-resident PI4P synthesis in chromosome 1q21.3-amplified lung adenocarcinoma cells.
Proceedings of the National Academy of Sciences of the United States of America
2021; 118 (25)
Abstract
A chromosome 1q21.3 region that is frequently amplified in diverse cancer types encodes phosphatidylinositol (PI)-4 kinase IIIbeta (PI4KIIIbeta), a key regulator of secretory vesicle biogenesis and trafficking. Chromosome 1q21.3-amplified lung adenocarcinoma (1q-LUAD) cells rely on PI4KIIIbeta for Golgi-resident PI-4-phosphate (PI4P) synthesis, prosurvival effector protein secretion, and cell viability. Here, we show that 1q-LUAD cells subjected to prolonged PI4KIIIbeta antagonist treatment acquire tolerance by activating an miR-218-5p-dependent competing endogenous RNA network that up-regulates PI4KIIalpha, which provides an alternative source of Golgi-resident PI4P that maintains prosurvival effector protein secretion and cell viability. These findings demonstrate an addiction to Golgi-resident PI4P synthesis in a genetically defined subset of cancers.
View details for DOI 10.1073/pnas.2023537118
View details for PubMedID 34155143
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Publisher Correction: A mouse-adapted model of SARS-CoV-2 to test COVID-19 countermeasures.
Nature
2021
View details for DOI 10.1038/s41586-020-03107-5
View details for PubMedID 33469219
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Durable virological response and functional cure of chronic hepatitis D after long-term peginterferon therapy.
Alimentary pharmacology & therapeutics
2021
Abstract
Hepatitis delta virus (HDV) infection is the most aggressive form of chronic viral hepatitis. Response rates to therapy with 1- to 2-year courses of pegylated interferon alpha (peginterferon) treatment are suboptimal.To evaluate the long-term outcomes of patients with chronic hepatitis D after an extended course of peginterferon.Patients were followed after completion of trial NCT00023322 and classified based on virological response defined as loss of detectable serum HDV RNA at last follow-up. During extended follow-up, survival and liver-related events were recorded.All 12 patients who received more than 6 months of peginterferon in the original study were included in this analysis. The cohort was mostly white (83%) and male (92%) and ranged in age from 18 to 58 years (mean = 42.6). Most patients had advanced but compensated liver disease at baseline, a median HBV DNA level of 536 IU per mL and median HDV RNA level of 6.86 log10 genome equivalents per mL. The treatment duration averaged 6.1 years (range 0.8-14.3) with a total follow-up of 8.8 years (range 1.7-17.6). At last follow-up, seven (58%) patients had durable undetectable HDV RNA in serum, and four (33%) cleared HBsAg. Overall, one of seven (14%) responders died or had a liver-related event vs four of five (80%) non-responders.With further follow-up, an extended course of peginterferon therapy was found to result in sustained clearance of HDV RNA and favourable clinical outcomes in more than half of patients and loss of HBsAg in a third.
View details for DOI 10.1111/apt.16408
View details for PubMedID 34048594
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Peginterferon lambda for the treatment of outpatients with COVID-19: a phase 2, placebo-controlled randomised trial.
The Lancet. Respiratory medicine
2021
Abstract
To date, only monoclonal antibodies have been shown to be effective for outpatients with COVID-19. Interferon lambda-1 is a type III interferon involved in innate antiviral responses with activity against respiratory pathogens. We aimed to investigate the safety and efficacy of peginterferon lambda in the treatment of outpatients with mild-to-moderate COVID-19.In this double-blind, placebo-controlled trial, outpatients with laboratory-confirmed COVID-19 were randomly assigned to a single subcutaneous injection of peginterferon lambda 180 μg or placebo within 7 days of symptom onset or first positive swab if asymptomatic. Participants were randomly assigned (1:1) using a computer-generated randomisation list created with a randomisation schedule in blocks of four. At the time of administration, study nurses received a sealed opaque envelope with the treatment allocation number. The primary endpoint was the proportion of patients who were negative for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA on day 7 after the injection, analysed by a χ2 test following an intention-to-treat principle. Prespecified analysis of the primary endpoint, adjusted for baseline viral load, using bivariate logistic regression was done. The trial is now complete. This trial is registered with ClinicalTrials.gov, NCT04354259.Between May 18, and Sept 4, 2020, we recruited 30 patients per group. The decline in SARS-CoV-2 RNA was greater in those treated with peginterferon lambda than placebo from day 3 onwards, with a difference of 2·42 log copies per mL at day 7 (p=0·0041). By day 7, 24 (80%) participants in the peginterferon lambda group had an undetectable viral load, compared with 19 (63%) in the placebo group (p=0·15). After controlling for baseline viral load, patients in the peginterferon lambda group were more likely to have undetectable virus by day 7 than were those in the placebo group (odds ratio [OR] 4·12 [95% CI 1·15-16·73; p=0·029). Of those with baseline viral load above 106 copies per mL, 15 (79%) of 19 patients in the peginterferon lambda group had undetectable virus on day 7, compared with six (38%) of 16 in the placebo group (OR 6·25 [95% CI 1·49-31·06]; p=0·012). Peginterferon lambda was well tolerated, and adverse events were similar between groups with mild and transient aminotransferase, concentration increases more frequently observed in the peginterferon lambda group. Two individuals met the threshold of grade 3 increase, one in each group, and no other grade 3 or 4 laboratory adverse events were reported.Peginterferon lambda accelerated viral decline in outpatients with COVID-19, increasing the proportion of patients with viral clearance by day 7, particularly in those with high baseline viral load. Peginterferon lambda has potential to prevent clinical deterioration and shorten duration of viral shedding.The Toronto COVID-19 Action Initiative, University of Toronto, and the Ontario First COVID-19 Rapid Research Fund, Toronto General & Western Hospital Foundation.
View details for DOI 10.1016/S2213-2600(20)30566-X
View details for PubMedID 33556319
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Signatures of immune dysfunction in HIV and HCV infection share features with chronic inflammation in aging and persist after viral reduction or elimination.
Proceedings of the National Academy of Sciences of the United States of America
2021; 118 (14)
Abstract
Chronic inflammation is thought to be a major cause of morbidity and mortality in aging, but whether similar mechanisms underlie dysfunction in infection-associated chronic inflammation is unclear. Here, we profiled the immune proteome, and cellular composition and signaling states in a cohort of aging individuals versus a set of HIV patients on long-term antiretroviral therapy therapy or hepatitis C virus (HCV) patients before and after sofosbuvir treatment. We found shared alterations in aging-associated and infection-associated chronic inflammation including T cell memory inflation, up-regulation of intracellular signaling pathways of inflammation, and diminished sensitivity to cytokines in lymphocytes and myeloid cells. In the HIV cohort, these dysregulations were evident despite viral suppression for over 10 y. Viral clearance in the HCV cohort partially restored cellular sensitivity to interferon-α, but many immune system alterations persisted for at least 1 y posttreatment. Our findings indicate that in the HIV and HCV cohorts, a broad remodeling and degradation of the immune system can persist for a year or more, even after the removal or drastic reduction of the pathogen load and that this shares some features of chronic inflammation in aging.
View details for DOI 10.1073/pnas.2022928118
View details for PubMedID 33811141
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Peginterferon Lambda-1a for treatment of outpatients with uncomplicated COVID-19: a randomized placebo-controlled trial.
Nature communications
2021; 12 (1): 1967
Abstract
Type III interferons have been touted as promising therapeutics in outpatients with coronavirus disease 2019 (COVID-19). We conducted a randomized, single-blind, placebo-controlled trial (NCT04331899) in 120 outpatients with mild to moderate COVID-19 to determine whether a single, 180 mcg subcutaneous dose of Peginterferon Lambda-1a (Lambda) within 72 hours of diagnosis could shorten the duration of viral shedding (primary endpoint) or symptoms (secondary endpoint). In both the 60 patients receiving Lambda and 60 receiving placebo, the median time to cessation of viral shedding was 7 days (hazard ratio [HR] = 0.81; 95% confidence interval [CI] 0.56 to 1.19). Symptoms resolved in 8 and 9 days in Lambda and placebo, respectively, and symptom duration did not differ significantly between groups (HR 0.94; 95% CI 0.64 to 1.39). Both Lambda and placebo were well-tolerated, though liver transaminase elevations were more common in the Lambda vs. placebo arm (15/60 vs 5/60; p = 0.027). In this study, a single dose of subcutaneous Peginterferon Lambda-1a neither shortened the duration of SARS-CoV-2 viral shedding nor improved symptoms in outpatients with uncomplicated COVID-19.
View details for DOI 10.1038/s41467-021-22177-1
View details for PubMedID 33785743
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Progenitor identification and SARS-CoV-2 infection in human distal lung organoids.
Nature
2020
Abstract
The distal lung contains terminal bronchioles and alveoli that facilitate gas exchange. Three-dimensional in vitro human distal lung culture systems would strongly facilitate investigation of pathologies including interstitial lung disease, cancer, and SARS-CoV-2-associated COVID-19 pneumonia. We generated long-term feeder-free, chemically defined culture of distal lung progenitors as organoids derived from single adult human alveolar epithelial type II (AT2) or KRT5+ basal cells. AT2 organoids exhibited AT1 transdifferentiation potential while basal cell organoids developed lumens lined by differentiated club and ciliated cells. Single cell analysis of basal organoid KRT5+ cells revealed a distinct ITGA6+ITGB4+ mitotic population whose proliferation further segregated to a TNFRSF12Ahi subfraction comprising ~10% of KRT5+ basal cells, residing in clusters within terminal bronchioles and exhibiting enriched clonogenic organoid growth activity. Distal lung organoids were created with apical-out polarity to display ACE2 on the exposed external surface, facilitating SARS-CoV-2 infection of AT2 and basal cultures and identifying club cells as a novel target population. This long-term, feeder-free organoid culture of human distal lung, coupled with single cell analysis, identifies unsuspected basal cell functional heterogeneity and establishes a facile in vitro organoid model for human distal lung infections including COVID-19-associated pneumonia.
View details for DOI 10.1038/s41586-020-3014-1
View details for PubMedID 33238290
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High Prevalence of Chronic Viral Hepatitis and Liver Fibrosis Among Mongols in Southern California.
Digestive diseases and sciences
2020
Abstract
BACKGROUND: Mongolia is a highly endemic region for chronic hepatitis B (HBV), hepatitis delta (HDV), and hepatitis C (HCV) infections. Aim of this study was to comprehensively characterize chronic viral hepatitis among Mongols living in Southern California.METHODS: Three screening events were conducted between August and November 2018, with 528 adult Mongols tested for HBV and HCV. HBsAg (+) individuals (CHB) underwent additional testing for HDV RNA and anti-HDV. Liver tests, platelet count, and FibroScan were performed on CHB and chronic HCV (CHC) individuals.RESULTS: Fifty-one out of 534 were HBsAg reactive (9.7%), and all were foreign-born. Mean age of CHB individuals was 37.8 (range 18-69) years. Forty-six out of 51 were HBeAg (-). HBV genotypes were exclusively D2 or A1. Twenty-one out of 51 (41.2%) were anti-HDV (+) and 17/51 (33.3%) were HDV RNA (+). HDV RNA (+) individuals had significantly higher ALT, fibrosis-4 score, and liver stiffness compared to HDV RNA (-) individuals. Incidence of advanced fibrosis was higher in HDV RNA (+) individuals (57% vs. 13%, p=0.013). Forty-eight (9.1%) individuals were anti-HCV (+) and 19 (3.6%) were HCV RNA (+). Mean age of CHC individuals was 40.2 (range 28-71) years. Prevalence of anti-HCV (+) was higher among those born between 1945 and 1965 versus those born after 1965 (18.8% vs. 7.9%, p=0.025). Genotype 1b was predominant. Incidence of cirrhosis was 7% among all participants.CONCLUSIONS: Mongols living in the USA are at high risk for CHB and CHC infections. One-third of CHB individuals had CHD superinfection with advanced fibrosis. Universal screening for viral hepatitis in Mongols in the USA is mandatory.
View details for DOI 10.1007/s10620-020-06499-6
View details for PubMedID 32770488
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A Phase 2 Study of Peginterferon Lambda, Lonafarnib and Ritonavir for 24 Weeks: End-of-Treatment Results from the LIFT HDV Study
ELSEVIER. 2020: S130
View details for Web of Science ID 000786587000211
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RNA genome conservation and secondary structure in SARS-CoV-2 and SARS-related viruses: a first look.
RNA (New York, N.Y.)
2020
Abstract
As the COVID-19 outbreak spreads, there is a growing need for a compilation of conserved RNA genome regions in the SARS-CoV-2 virus along with their structural propensities to guide development of antivirals and diagnostics. Here we present a first look at RNA sequence conservation and structural propensities in the SARS-CoV-2 genome. Using sequence alignments spanning a range of betacoronaviruses, we rank genomic regions by RNA sequence conservation, identifying 79 regions of length at least 15 nucleotides as exactly conserved over SARS-related complete genome sequences available near the beginning of the COVID-19 outbreak. We then confirm the conservation of the majority of these genome regions across 739 SARS-CoV-2 sequences subsequently reported from the COVID-19 outbreak, and we present a curated list of 30 'SARS-related-conserved' regions. We find that known RNA structured elements curated as Rfam families and in prior literature are enriched in these conserved genome regions, and we predict additional conserved, stable secondary structures across the viral genome. We provide 106 'SARS-CoV-2-conserved-structured' regions as potential targets for antivirals that bind to structured RNA. We further provide detailed secondary structure models for the extended 5' UTR, frame-shifting element, and 3' UTR. Last, we predict regions of the SARS-CoV-2 viral genome that have low propensity for RNA secondary structure and are conserved within SARS-CoV-2 strains. These 59 'SARS-CoV-2-conserved-unstructured' genomic regions may be most easily targeted in primer-based diagnostic and oligonucleotide-based therapeutic strategies.
View details for DOI 10.1261/rna.076141.120
View details for PubMedID 32398273
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COVID-19 and emerging viral infections: The case for interferon lambda.
The Journal of experimental medicine
2020; 217 (5)
Abstract
With the first reports on coronavirus disease 2019 (COVID-19), which is caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the scientific community working in the field of type III IFNs (IFN-lambda) realized that this class of IFNs could play an important role in this and other emerging viral infections. In this Viewpoint, we present our opinion on the benefits and potential limitations of using IFN-lambda to prevent, limit, and treat these dangerous viral infections.
View details for DOI 10.1084/jem.20200653
View details for PubMedID 32289152
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Extracellular cGAMP is a cancer cell-produced immunotransmitter involved in radiation-induced anti-cancer immunity.
Nature cancer
2020; 1 (2): 184-196
Abstract
2'3'-cyclic GMP-AMP (cGAMP) is an intracellular second messenger that is synthesized in response to cytosolic double-stranded DNA and activates the innate immune STING pathway. Our previous discovery of its extracellular hydrolase ENPP1 hinted at the existence of extracellular cGAMP. Here, we detected that cGAMP is continuously exported but then efficiently cleared by ENPP1, explaining why it has previously escaped detection. By developing potent, specific, and cell impermeable ENPP1 inhibitors, we found that cancer cells continuously export cGAMP in culture at steady state and at higher levels when treated with ionizing radiation (IR). In mouse tumors, depletion of extracellular cGAMP decreased tumor-associated immune cell infiltration and abolished the curative effect of IR. Boosting extracellular cGAMP with ENPP1 inhibitors synergized with IR to delay tumor growth. In conclusion, extracellular cGAMP is an anti-cancer immunotransmitter that could be harnessed to treat cancers with low immunogenicity.
View details for DOI 10.1038/s43018-020-0028-4
View details for PubMedID 33768207
View details for PubMedCentralID PMC7990037
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Extracellular cGAMP is a cancer-cell-produced immunotransmitter involved in radiation-induced anticancer immunity
NATURE CANCER
2020; 1 (2): 184-+
View details for DOI 10.1038/s43018-020-0028-4
View details for Web of Science ID 000608021200012
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Upregulation of CD47 Is a Host Checkpoint Response to Pathogen Recognition.
mBio
2020; 11 (3)
Abstract
It is well understood that the adaptive immune response to infectious agents includes a modulating suppressive component as well as an activating component. We now show that the very early innate response also has an immunosuppressive component. Infected cells upregulate the CD47 "don't eat me" signal, which slows the phagocytic uptake of dying and viable cells as well as downstream antigen-presenting cell (APC) functions. A CD47 mimic that acts as an essential virulence factor is encoded by all poxviruses, but CD47 expression on infected cells was found to be upregulated even by pathogens, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), that encode no mimic. CD47 upregulation was revealed to be a host response induced by the stimulation of both endosomal and cytosolic pathogen recognition receptors (PRRs). Furthermore, proinflammatory cytokines, including those found in the plasma of hepatitis C patients, upregulated CD47 on uninfected dendritic cells, thereby linking innate modulation with downstream adaptive immune responses. Indeed, results from antibody-mediated CD47 blockade experiments as well as CD47 knockout mice revealed an immunosuppressive role for CD47 during infections with lymphocytic choriomeningitis virus and Mycobacterium tuberculosis Since CD47 blockade operates at the level of pattern recognition receptors rather than at a pathogen or antigen-specific level, these findings identify CD47 as a novel potential immunotherapeutic target for the enhancement of immune responses to a broad range of infectious agents.IMPORTANCE Immune responses to infectious agents are initiated when a pathogen or its components bind to pattern recognition receptors (PRRs). PRR binding sets off a cascade of events that activates immune responses. We now show that, in addition to activating immune responses, PRR signaling also initiates an immunosuppressive response, probably to limit inflammation. The importance of the current findings is that blockade of immunomodulatory signaling, which is mediated by the upregulation of the CD47 molecule, can lead to enhanced immune responses to any pathogen that triggers PRR signaling. Since most or all pathogens trigger PRRs, CD47 blockade could be used to speed up and strengthen both innate and adaptive immune responses when medically indicated. Such immunotherapy could be done without a requirement for knowing the HLA type of the individual, the specific antigens of the pathogen, or, in the case of bacterial infections, the antimicrobial resistance profile.
View details for DOI 10.1128/mBio.01293-20
View details for PubMedID 32576678
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Materials science approaches in the development of broad-spectrum antiviral therapies.
Nature materials
2020
View details for DOI 10.1038/s41563-020-0698-4
View details for PubMedID 32427958
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PI4KIIIβ is a therapeutic target in chromosome 1q-amplified lung adenocarcinoma.
Science translational medicine
2020; 12 (527)
Abstract
Heightened secretion of protumorigenic effector proteins is a feature of malignant cells. Yet, the molecular underpinnings and therapeutic implications of this feature remain unclear. Here, we identify a chromosome 1q region that is frequently amplified in diverse cancer types and encodes multiple regulators of secretory vesicle biogenesis and trafficking, including the Golgi-dedicated enzyme phosphatidylinositol (PI)-4-kinase IIIβ (PI4KIIIβ). Molecular, biochemical, and cell biological studies show that PI4KIIIβ-derived PI-4-phosphate (PI4P) synthesis enhances secretion and accelerates lung adenocarcinoma progression by activating Golgi phosphoprotein 3 (GOLPH3)-dependent vesicular release from the Golgi. PI4KIIIβ-dependent secreted factors maintain 1q-amplified cancer cell survival and influence prometastatic processes in the tumor microenvironment. Disruption of this functional circuitry in 1q-amplified cancer cells with selective PI4KIIIβ antagonists induces apoptosis and suppresses tumor growth and metastasis. These results support a model in which chromosome 1q amplifications create a dependency on PI4KIIIβ-dependent secretion for cancer cell survival and tumor progression.
View details for DOI 10.1126/scitranslmed.aax3772
View details for PubMedID 31969487
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A mouse-adapted model of SARS-CoV-2 to test COVID-19 countermeasures.
Nature
2020
Abstract
Coronaviruses are prone to emergence into new host species most recently evidenced by SARS-CoV-2, the causative agent of the COVID-19 pandemic1. Small animal models that recapitulate SARS-CoV-2 disease are desperately needed to rapidly evaluate medical countermeasures (MCMs)2,3. SARS-CoV-2 cannot infect wildtype laboratory mice due to inefficient interactions between the viral spike (S) protein and the murine ortholog of the human receptor, ACE24. We used reverse genetics5 to remodel the interaction between S and mACE2 resulting in a recombinant virus (SARS-CoV-2 MA) that could utilize mACE2 for entry. SARS-CoV-2 MA replicated in both the upper and lower airways of both young adult and aged BALB/c mice. Importantly, disease was more severe in aged mice, and showed more clinically relevant phenotypes than those seen in HFH4-hACE2 transgenic mice. We then demonstrated the utility of this model through vaccine challenge studies in immune competent mice with native expression of mACE2. Lastly, we show that clinical candidate interferon (IFN) lambda-1a can potently inhibit SARS-CoV-2 replication in primary human airway epithelial cells in vitro, and both prophylactic and therapeutic administration diminished replication in mice. Our mouse-adapted SARS-CoV-2 model demonstrates age-related disease pathogenesis and supports the clinical use of pegylated IFN lambda-1a treatment in human COVID-19 infections6.
View details for DOI 10.1038/s41586-020-2708-8
View details for PubMedID 32854108
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Structure of the neurotensin receptor 1 in complex with β-arrestin 1.
Nature
2020
Abstract
Arrestin proteins bind to active, phosphorylated G-protein-coupled receptors (GPCRs), thereby preventing G-protein coupling, triggering receptor internalization, and affecting various downstream signalling pathways1,2. Although there is a wealth of structural information delineating the interactions between GPCRs and G proteins, less is known about how arrestins engage GPCRs. Here we report a cryo-EM structure of full-length human neurotensin receptor 1 (NTSR1) in complex with truncated human β-arrestin 1 (βarr1ΔCT). We found that phosphorylation of NTSR1 was critical for obtaining a stable complex with βarr1ΔCT, and identified phosphorylated sites in both the third intracellular loop and the C terminus that may promote this interaction. In addition, we observed a phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2) molecule forming a bridge between the membrane side of NTSR1 transmembrane segments 1 and 4 and the C-lobe of arrestin. Compared to a structure of rhodopsin-arrestin-1, our structure displays an approximately 85° rotation of arrestin relative to the receptor. These findings highlight both conserved aspects but also the plasticity of arrestin-receptor interactions.
View details for DOI 10.1038/s41586-020-1953-1
View details for PubMedID 31945771
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CHARACTERIZATION OF HDV, HBsAg AND ALT KINETICS UNDER PEGINTERFERON-LAMBDA MONOTHERAPY: THE PHASE 2 LIMT STUDY
WILEY. 2019: 1496A–1497A
View details for Web of Science ID 000500824000066
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A PHASE 2 STUDY OF LONAFARNIB, RITONAVIR AND PEGINTERFERON LAMBDA FOR 24 WEEKS: INTERIM END-OF-TREATMENT RESULTS FROM THE LIFT HDV STUDY.
WILEY. 2019: 1483A
View details for Web of Science ID 000500824000051
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2 ' 3 '-cGAMP is an immunotransmitter produced by cancer cells and regulated by ENPP1
AMER CHEMICAL SOC. 2019
View details for Web of Science ID 000525061505479
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HBV/HDV Coinfection: A Challenge for Therapeutics.
Clinics in liver disease
2019; 23 (3): 557–72
Abstract
Chronic hepatitis D (CHD) results from an infection with the hepatitis B virus and hepatitis D virus (HDV). CHD is the most severe form of human viral hepatitis. Current treatment options consist of interferon alfa, which is effective only in a minority of patients. Study of HDV molecular virology has resulted in new approaches entering clinical trials, with phase-3 studies the most advanced. These include the entry inhibitor bulevirtide, the nucleic acid polymer REP 2139-Ca, the farnesyltransferase inhibitor lonafarnib, and pegylated interferon lambda. This article summarizes the available data on these emerging therapeutics.
View details for DOI 10.1016/j.cld.2019.04.005
View details for PubMedID 31266627
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Hepatitis D virus infection, cirrhosis and hepatocellular carcinoma in The Gambia
JOURNAL OF VIRAL HEPATITIS
2019; 26 (6): 738–49
View details for DOI 10.1111/jvh.13065
View details for Web of Science ID 000469027000013
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Treating chronic hepatitis delta: The need for surrogate markers of treatment efficacy
JOURNAL OF HEPATOLOGY
2019; 70 (5): 1008–15
View details for DOI 10.1016/j.jhep.2018.12.022
View details for Web of Science ID 000464016500023
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Treating chronic hepatitis delta: The need for surrogate markers of treatment efficacy.
Journal of hepatology
2019; 70 (5): 1008–15
Abstract
Chronic hepatitis delta represents the most severe form of chronic viral hepatitis. The current treatment of hepatitis delta virus (HDV) infection consists of the use of interferons and is largely unsatisfactory. Several new compounds are currently in development for the treatment of HDV infection. However, surrogate markers that can be used to develop clinical endpoints in HDV infection are not well defined. In the current manuscript, we aimed to evaluate the existing data on treatment of HDV infection and to suggest treatment goals (possible "trial endpoints") that could be used across different clinical trials.
View details for PubMedID 30982526
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End of study results from LIMT HDV study: 36% durable virologic response at 24 weeks post-treatment with pegylated interferon lambda monotherapy in patients with chronic hepatitis delta virus infection
ELSEVIER SCIENCE BV. 2019: E32
View details for Web of Science ID 000463481700059
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The balance of type 1 and type 2 immune responses in the contexts of hepatitis B infection and hepatitis D infection
JOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY
2019; 34 (4): 764–75
View details for DOI 10.1111/jgh.14617
View details for Web of Science ID 000462611300026
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Early Multiphasic HBV Infection Initiation Kinetics Is Not Clone-Specific and Is Not Affected by Hepatitis D Virus (HDV) Infection
VIRUSES-BASEL
2019; 11 (3)
View details for DOI 10.3390/v11030263
View details for Web of Science ID 000464393800001
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Early Multiphasic HBV Infection Initiation Kinetics Is Not Clone-Specific and Is Not Affected by Hepatitis D Virus (HDV) Infection.
Viruses
2019; 11 (3)
Abstract
Backgrounds and Aims: We previously demonstrated that serum hepatitis B virus (HBV) DNA in HBV infected humanized mice exhibited a highly dynamic multiphasic kinetic pattern from infection initiation to steady-state. Here, we investigated whether this pattern is consistent across different HBV clones or in the presence of hepatitis D virus (HDV) co-infection. Methods: We analyzed early serum viral kinetics using 26 HBV genotype C (GtC) mono-infected mice [clones: PXB, Hiroshima GtC CL4 (CL4) and Hiroshima GtC CL5 (CL5)] and four HBV CL4/HDV genotype one co-infected mice. Results: The HBV kinetics observed with clones CL4 and CL5 were similar to that previously defined in HBV PXB infected mice. Additionally, no significant differences in HBV DNA levels were observed between HBV mono-infected and HBV/HDV co-infected mice through 4 weeks post-inoculation (p.i.). However, HBV DNA levels at 6 weeks p.i. in HBV/HDV co-infected mice were significantly lower than those in HBV mono-infected mice (P = 0.002), consistent with HDV suppression of chronic HBV. Conclusions: HBV infection initiation is multiphasic across multiple viral clones and is not altered by HDV co-infection. The latter suggests that higher HDV titers (>8 log IU/mL) and/or longer duration of HDV infection might be needed to trigger HDV-induced suppression on HBV.
View details for PubMedID 30875937
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Changing Trends in Etiology-Based and Ethnicity-Based Annual Mortality Rates of Cirrhosis and Hepatocellular Carcinoma in the United States
HEPATOLOGY
2019; 69 (3): 1064–74
View details for DOI 10.1002/hep.30161
View details for Web of Science ID 000459816500013
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A functional subset of CD8(+) T cells during chronic exhaustion is defined by SIRP alpha expression
NATURE COMMUNICATIONS
2019; 10
View details for DOI 10.1038/s41467-019-08637-9
View details for Web of Science ID 000458755400008
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A functional subset of CD8+ T cells during chronic exhaustion is defined by SIRPalpha expression.
Nature communications
2019; 10 (1): 794
Abstract
Prolonged exposure of CD8+ T cells to antigenic stimulation, as in chronic viral infections, leads to a state of diminished function termed exhaustion. We now demonstrate that even during exhaustion there is a subset of functional CD8+ T cells defined by surface expression of SIRPalpha, a protein not previously reported on lymphocytes. On SIRPalpha+ CD8+ T cells, expression of co-inhibitory receptors is counterbalanced by expression of co-stimulatory receptors and it is only SIRPalpha+ cells that actively proliferate, transcribe IFNgamma and show cytolytic activity. Furthermore, target cells that express the ligand for SIRPalpha, CD47, are more susceptible to CD8+ T cell-killing in vivo. SIRPalpha+ CD8+ T cells are evident in mice infected with Friend retrovirus, LCMV Clone 13, and in patients with chronic HCV infections. Furthermore, therapeutic blockade of PD-L1 to reinvigorate CD8+ T cells during chronic infection expands the cytotoxic subset of SIRPalpha+ CD8+ T cells.
View details for PubMedID 30770827
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The balance of type 1 and type 2 immune responses in the contexts of hepatitis B infection and hepatitis D infection.
Journal of gastroenterology and hepatology
2019
Abstract
BACKGROUND: Hepatitis delta virus (HDV) infection is the most rapidly progressive chronic viral hepatitis. Little is understood about the immune responses to HDV.AIM: To characterize the systemic immune environments of hepatitis B virus (HBV) and HDV patients at various disease stages.METHODS: Evaluated 129 subjects; 53 HBV, 43 HDV, 33 healthy controls. HBV and HDV subjects were categorized by aspartate aminotransferase to platelet ratio index (APRI) into mild (APRI < 0.5), moderate, and severe (APRI > 1.0). Serum cytokines and immune markers were assessed at a single treatment-naive time-point.RESULTS: Type 1 cytokines are elevated in both HBV and HDV. Both groups show higher TNFa, IL-12p40, and CXCL9 when compared to controls (all p< 0.05). However, only HBV group displayed elevated IFNg compared to controls. Type 2 cytokines are elevated in HBV. HBV group shows higher IL-4, IL-13, and CCL26 compared to healthy controls and HDV. Chemokine CCL2 and CCL13 are lower in HDV. When assessing ratios, HDV displays higher IFNg/IL-4, TNFa/IL-4, and TNFa/IL-13 ratios than HBV and controls.CONCLUSION: HBV and HDV subjects show similarly elevated type 1 cytokines. HDV subjects display relatively lower type 2 cytokines. These differences in the systemic immune environments, particularly the predominance of type 1 responses, may contribute to the comparatively rapid progression of HDV disease.TRANSLATIONAL IMPACT: Characterization of the imbalance in type 1 and type 2 immunity unique HDV has the potential to provide immunological insights for designing therapeutic targets in HDV associated disease progression.
View details for PubMedID 30695096
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Hepatitis D virus infection, cirrhosis, and hepatocellular carcinoma in The Gambia.
Journal of viral hepatitis
2019
Abstract
Hepatocellular carcinoma (HCC) incidence is high in The Gambia and hepatitis B virus (HBV) infection is the main cause. People co-infected with HBV and hepatitis D virus (HDV) have an even greater risk of HCC and cirrhosis. Using a new HDV quantitative microarray antibody capture (Q-MAC) assay, we evaluated the association between HDV infection and HCC or cirrhosis among participants in The Gambia Liver Cancer Study. In this case-control study, cases had HCC (n=312) or cirrhosis (n=119). Controls (n=470) had no clinical evidence of liver disease and normal serum alfa-fetoprotein. Participants were previously tested for hepatitis B surface antigen (HBsAg); we tested HBsAg+ specimens by HDV Q-MAC, western blot, and RNA assays. We evaluated separate cutoffs of the Q-MAC assay for predicting anti-HDV and RNA positivity. Q-MAC correctly identified 29/29 subjects who were western blot positive (sensitivity=100%, specificity=99.4%) and 16/17 who were RNA positive (sensitivity=94.1%, specificity=100%). Compared to controls, cases more often had HBV monoinfection (HBsAg+/HDV RNA-; 54.1% vs. 17.0%; odds ratio [OR]= 6.28; p<0.001) or HBV-HDV coinfection (HBsAg+/HDV RNA+; 3.9% vs 0%; OR=; p<0.001). Risk estimates (for HCC or cirrhosis) based on HDV antibody status and adjusted for covariates (demographics, alcohol, smoking, body mass index, anti-HCV, and aflatoxin B1 exposure) yielded consistent results for both HBV monoinfection (adjusted OR=8.29; 95% confidence interval=5.74-11.98) and HBV-HDV coinfection (adjusted OR=30.66; 95% confidence interval=6.97-134.95). In this Gambian population, HDV Q-MAC had high sensitivity and specificity for both anti-HDV and HDV RNA. HDV infection contributed to the high risk of HCC in The Gambia. This article is protected by copyright. All rights reserved.
View details for PubMedID 30661282
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Trends in Mortality From Extrahepatic Complications in Patients With Chronic Liver Disease, From 2007 Through 2017.
Gastroenterology
2019
Abstract
Trends of mortality associated with extrahepatic complications of chronic liver disease might be changing. We studied trends in mortality from extrahepatic complications of viral hepatitis, alcoholic liver disease (ALD), and nonalcoholic fatty liver disease in the United States (US).We performed a population-based study using US Census and the National Center for Health Statistics mortality records, from 2007 through 2017. We identified trends in age-standardized mortality using joinpoint trend analysis with estimates of annual percentage change.The liver-related mortality among patients with hepatitis C virus (HCV) infection increased from 2007 through 2013 and then decreased once patients began receiving treatment with direct-acting antiviral (DAA) agents, from 2014 through 2017. Among patients with HCV infection, the age-standardized mortality for extrahepatic cancers was 2.6%, for cardiovascular disease was 1.9%, and for diabetes was 3.3%. Among individuals with hepatitis B virus infection, liver-related mortality decreased steadily from 2007 through 2017. During the study age-standardized mortality from hepatitis B virus-related extrahepatic complications increased with an average annual percentage of 2.0%. Although liver-related mortality from ALD continued to increase, mortality from extrahepatic complications of ALD did not change significantly during the 11-year study. Among patients with nonalcoholic fatty liver disease, the cause of death was most frequently cardiovascular disease, which increased gradually over the study period, whereas liver-related mortality increased rapidly.In an analysis of US Census and the National Center for Health Statistics mortality records, we found that after widespread use of DAA agents for treatment of viral hepatitis, cause-specific mortality from extrahepatic cancers increased, whereas mortality from cardiovascular disease or diabetes increased only among patients with HCV infection. These findings indicate the need to reassess risk and risk factors for extrahepatic cancer, cardiovascular disease, and diabetes in individuals successfully treated for HCV infection with DAA agents.
View details for DOI 10.1053/j.gastro.2019.06.026
View details for PubMedID 31251928
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Fuzhenghuayu Decoction ameliorates hepatic fibrosis by attenuating experimental sinusoidal capillarization and liver angiogenesis.
Scientific reports
2019; 9 (1): 18719
Abstract
Fuzhenghuayu (FZHY) is a compound extracted from natural plants. Its anti-fibrotic effect has been confirmed in experimental and clinical studies. However, precise effects and underlying mechanisms of FZHY in liver angiogenesis largely remain understood. In this study, we investigated the effects of FZHY on sinusoidal capillarization and angiogenesis with mice challenged for Carbon tetrachloride (CCl4) and dimethylnitrosamine (DMN), in vitro human hepatic sinusoidal endothelial cells (HHSEC) and Human Umbilical Vein Endothelial Cell (HUVEC) 3D fibrin gel model. Besides its anti-fibrotic effect, FZHY ameliorated CCl4 and DMN-induced sinusoidal capillarization, angiogenesis and expression of angiogenesis-associated factors, i.e. CD31, VEGF, VEGF receptor II, phosphor-ERK and HIF-1α. Consistent with the findings based on animal models, inhibitory effects of FZHY on capillarization and angiogenesis were further confirmed in HHSEC and the HUVEC 3D fibrin gel model, respectively. These data suggest that FZHY ameliorates not only liver fibrosis but also vessel remodeling in experimental models. Therefore, FZHY might be a potentially useful drug to treat liver cirrhosis in clinical practice.
View details for DOI 10.1038/s41598-019-54663-4
View details for PubMedID 31822697
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Pathogenesis of and New Therapies for Hepatitis D
GASTROENTEROLOGY
2019; 156 (2): 461-+
View details for DOI 10.1053/j.gastro.2018.09.058
View details for Web of Science ID 000455964900014
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Human iPS derived progenitors bioengineered into liver organoids using an inverted colloidal crystal poly (ethylene glycol) scaffold
BIOMATERIALS
2018; 182: 299–311
View details for DOI 10.1016/j.biomaterials.2018.07.043
View details for Web of Science ID 000444928200028
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Pathogenesis of and New Therapies for Hepatitis D.
Gastroenterology
2018
Abstract
Hepatitis delta virus (HDV) infection of humans was first reported in 1977, and now it is now estimated that 15-20 million people are infected worldwide. Infection with HDV can be an acute or chronic process that occurs only in patients with an HBV infection. Chronic HDV infection commonly results in the most rapidly progressive form of viral hepatitis; it is the chronic viral infection that is most likely to lead to cirrhosis, and it is associated with an increased risk of hepatocellular carcinoma. HDV infection is the only chronic human hepatitis virus infection without a therapy approved by the Food and Drug Administration. Peginterferon alpha is the only recommended therapy, but it produces unsatisfactory results. We review therapeutic agents in development, designed to disrupt the HDV life cycle, that might benefit patients with this devastating disease.
View details for PubMedID 30342879
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Changing Trends in Etiology-Based Annual Mortality From Chronic Liver Disease, From 2007 Through 2016
GASTROENTEROLOGY
2018; 155 (4): 1154-+
View details for DOI 10.1053/j.gastro.2018.07.008
View details for Web of Science ID 000446327500041
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A Challenging Case of Triple Hepatitis Virus Infection: An Accurate Diagnostic Test for Hepatitis D Virus Is Urgently Needed
NATURE PUBLISHING GROUP. 2018: S1245
View details for Web of Science ID 000464611004215
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A new dual-targeting real-time RT-PCR assay for hepatitis D virus RNA detection
DIAGNOSTIC MICROBIOLOGY AND INFECTIOUS DISEASE
2018; 92 (2): 112–17
Abstract
In this study, a real-time reverse transcription-polymerase chain reaction (real time RT-PCR) assay targeting 2 genetic segments was established to detect HDV RNA. Utilizing the World Health Organization International Standard for Hepatitis D Virus RNA, the lower limit of detection was 575 IU/mL, and the linearity of quantification ranged from 575,000 IU/mL to 575 IU/mL. 384 HBsAg-positive samples collected from China were tested by this method and HDV antibody detection. Eleven samples were positive for anti-HDV IgG which may persist after HDV resolution, 6 samples were HDV RNA positive, and 5 samples were positive for anti-HDV IgM. This assay showed more sensitivity than the detection of anti-HDV IgM. These data demonstrate that the real-time RT-PCR assay for HDV RNA could be implemented in the clinical detection of HDV infection in chronic HBV-infected patients in China.
View details for PubMedID 29941366
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Impact of Drug Overdose Deaths on Solid Organ Transplantation in the United States
JOURNAL OF GENERAL INTERNAL MEDICINE
2018; 33 (9): 1423–25
View details for DOI 10.1007/s11606-018-4477-8
View details for Web of Science ID 000442642300005
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Human iPS derived progenitors bioengineered into liver organoids using an inverted colloidal crystal poly (ethylene glycol) scaffold.
Biomaterials
2018; 182: 299–311
Abstract
Generation of human organoids from induced pluripotent stem cells (iPSCs) offers exciting possibilities for developmental biology, disease modelling and cell therapy. Significant advances towards those goals have been hampered by dependence on animal derived matrices (e.g. Matrigel), immortalized cell lines and resultant structures that are difficult to control or scale. To address these challenges, we aimed to develop a fully defined liver organoid platform using inverted colloid crystal (ICC) whose 3-dimensional mechanical properties could be engineered to recapitulate the extracellular niche sensed by hepatic progenitors during human development. iPSC derived hepatic progenitors (IH) formed organoids most optimally in ICC scaffolds constructed with 140 mum diameter pores coated with type I collagen in a two-step process mimicking liver bud formation. The resultant organoids were closer to adult tissue, compared to 2D and 3D controls, with respect to morphology, gene expression, protein secretion, drug metabolism and viral infection and could integrate, vascularise and function following implantation into livers of immune-deficient mice. Preliminary interrogation of the underpinning mechanisms highlighted the importance of TGFbeta and hedgehog signalling pathways. The combination of functional relevance with tuneable mechanical properties leads us to propose this bioengineered platform to be ideally suited for a range of future mechanistic and clinical organoid related applications.
View details for PubMedID 30149262
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Changing Trends in Etiology- and Ethnicity-Based Annual Mortality Rates of Cirrhosis and Hepatocellular Carcinoma in the United States.
Hepatology (Baltimore, Md.)
2018
Abstract
With recent improvements in the treatment of end-stage liver disease (ESLD), a better understanding of the burden of cirrhosis and hepatocellular carcinoma (HCC) is needed in the United States (US). A population-based study using the US Census and national mortality database was performed. We identified the age-standardized etiology-specific mortality rates for cirrhosis and HCC among US adults aged ≥ 20 years from 2007 to 2016. We determined temporal mortality rate patterns by joinpoint analysis with estimates of annual percentage change (APC). Age-standardized cirrhosis-related mortality rates increased from 19.77/100,000 persons in 2007 to 23.67 in 2016 with an annual increase of 2.3% (95% CI 2.0-2.7). The APC in mortality rates for hepatitis C virus (HCV)-cirrhosis shifted from a 2.9% increase per year during 2007-2014 to a 6.5% decline per year during 2014-2016. Meanwhile, mortality for cirrhosis from alcoholic liver disease (ALD, APC 4.5%) and nonalcoholic fatty liver disease (NAFLD, APC 15.4%) increased over the same period, while mortality for hepatitis B virus (HBV)-cirrhosis decreased with an average APC of -1.1%. HCC-related mortality increased from 3.48/100,000 persons in 2007 to 4.41 in 2016 at an annual rate of 2.0% (95% CI 1.3-2.6). Etiology-specific mortality rates of HCC were largely consistent with cirrhosis-related mortality. Minority populations had a higher burden of HCC-related mortality.CONCLUSION: Cirrhosis- and HCC-related mortality rates increased between 2007 and 2016 in the US. However, mortality rates in HCV-cirrhosis demonstrated a significant decline from 2014-2016, during the direct-acting antiviral era. Mortality rates for ALD/NAFLD-cirrhosis and HCC have continued to increase, while HBV-cirrhosis-related mortality declined during the 10-year period. Importantly, minorities had a disproportionately higher burden of ESLD-related mortality. This article is protected by copyright. All rights reserved.
View details for PubMedID 30014489
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Changing Trends in Etiology-based Annual Mortality From Chronic Liver Disease, From 2007 Through 2016.
Gastroenterology
2018
Abstract
BACKGROUND & AIMS: Although treatment of hepatitis C virus (HCV) infection has improved, the prevalence of alcoholic liver disease (ALD) has been increasing, so we need an updated estimate of the burden and etiology-specific mortality of chronic liver diseases. We studied the trends in age-standardized mortality of chronic liver diseases among adults 20 years or older in the United States (US), from 2007 through 2016.METHODS: We collected data from the US Census and National Center for Health Statistics mortality records, identifying individuals with HCV infection, ALD, nonalcoholic fatty liver disease (NAFLD), or hepatitis B virus (HBV) infection using ICD-10 codes. We obtained temporal mortality rate patterns using joinpoint trend analysis with estimates of annual percentage change (APC).RESULTS: Age-standardized HCV-related mortality increased from 7.17/100,000 persons in 2007 to 8.14/100,000 persons in 2013, followed by a marked decrease in the time period at which patients began receiving treatment with direct-acting antiviral agents (from 8.09/100,000 persons in 2014 to 7.15/100,000 persons in 2016). The APC in HCV mortality increased 2.0%/year from 2007 through 2014, but decreased 6.4%/year from 2014 through 2016. In contrast, age-standardized mortality increased for ALD (APC of 2.3% from 2007 through 2013 and APC of 5.5% from 2013 through 2016) and NAFLD (APC of 6.1% from 2007 through 2013 and APC of 11.3% from 2013 through 2016). HBV-related mortality decreased steadily from 2007 through 2016, with an average APC of -2.1% (95% CI, -3.0 to -1.2). Etiology-based mortality in minority populations were higher. HCV-related mortality (per 100,000 persons) was highest among non-Hispanic blacks (10.28) and whites (6.92), followed by Hispanics (5.94), and lowest among non-Hispanic Asians (2.33). Non-Hispanic Asians had higher mortality for HBV infection (2.82 per 100,000 vs 1.02 for non-Hispanic blacks, and 0.47 for non-Hispanic whites).CONCLUSION: In our population-based analysis of chronic liver disease mortality in the US, the decline in HCV-related mortality coincided with the introduction of direct-acting antiviral therapies, while the mortality from ALD and NAFLD increased during the same period. Minorities in the US have disproportionately higher chronic liver disease-related mortality.
View details for PubMedID 30009816
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Hepatitis D Viremia Among Injection Drug Users in San Francisco
JOURNAL OF INFECTIOUS DISEASES
2018; 217 (12): 1902–6
Abstract
People who inject drugs (PWID) are commonly exposed to hepatitis B virus (HBV) and hepatitis D virus (HDV). We evaluated the prevalence of HDV viremia among hepatitis B surface antigen (HBsAg)-positive PWID (n = 73) using a new quantitative microarray antibody capture (Q-MAC) assay, HDV western blot, and HDV RNA. HDV Q-MAC performed well in this cohort: anti-HDV, 100% sensitivity and specificity; HDV viremia, 61.5% sensitivity and 100% specificity. Hepatitis D viremia was present in 35.6% of HBsAg-positive participants and was more common in those with resolved compared to chronic hepatitis C (5.1% vs 0.6%; adjusted odds ratio, 9.80; P < .0001).
View details for PubMedID 29800369
View details for PubMedCentralID PMC5972608
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Impact of Drug Overdose Deaths on Solid Organ Transplantation in the United States.
Journal of general internal medicine
2018
View details for PubMedID 29766381
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Optimizing lonafarnib treatment for the management of chronic delta hepatitis: The LOWR HDV-1 study
HEPATOLOGY
2018; 67 (4): 1224–36
Abstract
In a proof-of-concept (POC) study, the oral prenylation inhibitor, lonafarnib (LNF), decreased hepatitis D virus (HDV) RNA during 4 weeks of treatment. Here, we explored optimal LNF regimens. Fifteen patients (five groups; 3 per group) completed dosing as follows: (1) LNF 200 mg twice-daily (BID; 12 weeks); (2) LNF 300 mg BID (12 weeks); (3) LNF 100 mg thrice-daily (5 weeks); (4) LNF 100 mg BID + pegylated interferon alfa (PEG-IFNα) 180 μg once-weekly (QW; 8 weeks); and (5) LNF 100 mg BID + ritonavir (RTV) 100 mg once-daily (QD; 8 weeks). Tolerability and efficacy were assessed. Higher LNF monotherapy doses had greater decreases in HDV viral load than achieved in the original POC study. However, this was associated with increased gastrointestinal adverse events. Addition of RTV 100 mg QD to a LNF 100 mg BID regimen yielded better antiviral responses than LNF 300 mg BID monotherapy and with less side effects. A similar improvement was observed with LNF 100 mg BID + PEG-IFNα 180 μg QW. Two of 6 patients who received 12 weeks of LNF experienced transient posttreatment alanine aminotransferase (ALT) increases resulting in HDV-RNA negativity and ALT normalization.The cytochrome P450 3A4 inhibitor, RTV, allows a lower LNF dose to be used while achieving higher levels of postabsorption LNF, yielding better antiviral responses and tolerability. In addition, combining LNF with PEG-IFNα achieved more substantial and rapid HDV-RNA reduction, compared to historical responses with PEG-IFNα alone. Twelve weeks of LNF can result in posttreatment HDV-RNA negativity in some patients, which we speculate results from restoring favorable immune responses. These results support further development of LNF with RTV boosting and exploration of the combination of LNF with PEG-IFN. (Hepatology 2018;67:1224-1236).
View details for DOI 10.1002/hep.29658
View details for Web of Science ID 000428332600010
View details for PubMedID 29152762
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A research agenda for curing chronic hepatitis B virus infection
HEPATOLOGY
2018; 67 (3): 1127–31
View details for PubMedID 28877549
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Research priorities for the discovery of a cure for chronic hepatitis B: Report of a workshop
ANTIVIRAL RESEARCH
2018; 150: 93–100
Abstract
In early 2017, the Hepatitis B Foundation invited 30 experts in the fields of hepatitis B and liver cancer research to identify projects they deemed important to the goal of finding a cure for chronic hepatitis B and D and the diseases with which these viral infections are associated. They were also asked to identify general categories of research and to prioritize sub-project topics within those areas. The experts generally agreed on broadly defined areas of research, but there was usually little difference between the highest and lowest scoring projects; for the most part, all programs described in this document were considered valuable and necessary. An executive summary of this discussion was recently published (Alter et al., Hepatology 2017). The present manuscript reports the areas of research identified by the workshop participants, provides a brief rationale for their selection, and attempts to express differences among the priorities assigned to each area of research, when such distinctions were expressed.
View details for PubMedID 29248746
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Letter to the Editor regarding article "Emerging concepts for the treatment of hepatitis delta" [Menashe Elazar and Jeffrey S Glenn, Curr Opin Virol 24 (2017) 55-59] Reply
CURRENT OPINION IN VIROLOGY
2018; 28: 169
View details for PubMedID 29456115
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Emerging Therapeutic Targets for Hepatitis Delta Virus Infection.
Gastroenterology & hepatology
2018; 14 (1): 47–49
View details for PubMedID 29491762
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Structure of an engineered IFN-lambda/IFN-lambda R1/IL-10R beta complex provides insight into the functional dichotomy of type III versus type I IFNs
ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD. 2017: 46
View details for Web of Science ID 000414817600105
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Hepatitis B Virus Reactivation Associated With Direct-Acting Antiviral Therapy for Chronic Hepatitis C Virus
ANNALS OF INTERNAL MEDICINE
2017; 167 (10): 759–60
View details for PubMedID 29159388
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Prevalence of hepatitis D viremia among injection drug users in San Francisco
WILEY. 2017: 100A
View details for Web of Science ID 000412089800174
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Modeling hepatitis delta virus dynamics during ritonavir boosted lonafarnib treatment-the LOWR HDV-3 study
WILEY. 2017: 21A
View details for Web of Science ID 000412089800039
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Quantitative Evaluation of Viral Protein Binding to Phosphoinositide Receptors and Pharmacological Inhibition
ANALYTICAL CHEMISTRY
2017; 89 (18): 9742–50
Abstract
There is significant interest in developing analytical methods to characterize molecular recognition events between proteins and phosphoinositides, which are a medically important class of carbohydrate-functionalized lipids. Within this scope, one area of high priority involves quantitatively evaluating drug candidates that pharmacologically inhibit protein-phosphoinositide interactions. As full-length proteins are often difficult to produce, establishing methods to study these interactions with shorter, bioactive peptides would be advantageous. Herein, we report an atomic force microscopy (AFM)-based force spectroscopic approach to detect the specific interaction between an amphipathic, α-helical (AH) peptide derived from the hepatitis C virus NS5A protein and its biological target, the phosphatidylinositol (4,5)-bisphosphate [PI(4,5)P2] phosphoinositide receptor. After optimization of the peptide tethering strategy and measurement parameters, the binding specificity of AH peptide for PI(4,5)P2 receptors was comparatively evaluated across a panel of phosphoinositides and the influence of ionic strength on AH-PI(4,5)P2 binding strength was tested. Importantly, these capabilities were translated into the development of a novel experimental methodology to determine the inhibitory activity of a small-molecule drug candidate acting against the AH-PI(4,5)P2 interaction, and extracted kinetic parameters agree well with literature values obtained by conventional biochemical methods. Taken together, our findings provide a nanomechanical basis for explaining the high binding specificity of the NS5A AH to PI(4,5)P2 receptors, in turn establishing an analytical framework to study phosphoinositide-binding viral peptides and proteins as well as a broadly applicable approach to evaluate candidate inhibitors of protein-phosphoinositide interactions.
View details for PubMedID 28809547
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Long-term culture of human liver tissue with advanced hepatic functions.
JCI insight
2017; 2 (11)
Abstract
A major challenge for studying authentic liver cell function and cell replacement therapies is that primary human hepatocytes rapidly lose their advanced function in conventional, 2-dimensional culture platforms. Here, we describe the fabrication of 3-dimensional hexagonally arrayed lobular human liver tissues inspired by the liver's natural architecture. The engineered liver tissues exhibit key features of advanced differentiation, such as human-specific cytochrome P450-mediated drug metabolism and the ability to support efficient infection with patient-derived inoculums of hepatitis C virus. The tissues permit the assessment of antiviral agents and maintain their advanced functions for over 5 months in culture. This extended functionality enabled the prediction of a fatal human-specific hepatotoxicity caused by fialuridine (FIAU), which had escaped detection by preclinical models and short-term clinical studies. The results obtained with the engineered human liver tissue in this study provide proof-of-concept determination of human-specific drug metabolism, demonstrate the ability to support infection with human hepatitis virus derived from an infected patient and subsequent antiviral drug testing against said infection, and facilitate detection of human-specific drug hepatotoxicity associated with late-onset liver failure. Looking forward, the scalability and biocompatibility of the scaffold are also ideal for future cell replacement therapeutic strategies.
View details for DOI 10.1172/jci.insight.90853
View details for PubMedID 28570275
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Hepatitis delta infection - Current and new treatment options
BEST PRACTICE & RESEARCH CLINICAL GASTROENTEROLOGY
2017; 31 (3): 321–27
Abstract
In humans, hepatitis D virus (HDV) infection only occurs in the presence of a concomitant hepatitis B virus (HBV) infection, and induces the most severe form of human viral hepatitis. Even though HDV is spread worldwide and is endemic in some regions, screening and treatment has been often neglected in part due to the lack of an effective therapy. Moreover, HDV prevalence rates are increasing in many countries driven by immigration from areas of high endemicity. Currently, no FDA-approved anti-HDV therapy is available, although interferon (IFN) alpha therapy has demonstrated benefit in a minority of patients. In this review, we present a current view of our understanding of the epidemiology, molecular virology and management of HDV infection. We additionally discuss new treatment approaches in development and describe the most promising results of recent and ongoing clinical trials of these new potential agents.
View details for PubMedID 28774414
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Pharmacokinetics and Pharmacodynamics Modeling of Lonafarnib in Patients With Chronic Hepatitis Delta Virus Infection
HEPATOLOGY COMMUNICATIONS
2017; 1 (4): 288–92
Abstract
The prenylation inhibitor lonafarnib (LNF) is a potent antiviral agent providing a breakthrough for the treatment of hepatitis delta virus (HDV). The current study used a maximum likelihood approach to model LNF pharmacokinetic (PK) and pharmacodynamic (PD) parameters and predict the dose needed to achieve 99% efficacy using data from 12 patients chronically infected with HDV and treated with LNF 100 mg twice daily (bid) (group 1) or 200 mg bid (group 2) for 28 days. The LNF-PK model predicted average steady-state LNF concentrations of 860 ng/mL and 1,734 ng/mL in groups 1 and 2, respectively, with an LNF absorption rate ka = 0.43/hour and elimination rate ke = 0.045/hour. The PK/PD model identified an average delay of 0.56 hours and an LNF concentration that decreases HDV production by 50%, EC50 = 227 ng/mL, with a Hill factor h = 1.48. The HDV half-life in blood was 1.87 days, and the average steady-state LNF efficacy in blocking HDV production was ɛ = 87.7% for group 1 and ɛ = 95.2% for group 2. A biphasic HDV decline with an average phase 1 decline (0.9 log10 IU/mL and 1.32 log10 IU/mL) was observed in groups 1 and 2, respectively. Phase 2 was not significantly (P = 0.94) different between the two groups, with an average slope of -0.06 log IU/mL/day. The model suggests an LNF dose of ∼610 mg bid would achieve ɛ = 99%. Conclusion: The first PK/PD modeling study in patients with chronic HDV indicates that a ∼3-fold increase in LNF dose (∼610 mg bid) would achieve 99% antiviral efficacy. A ritonavir-boosted LNF combination may provide a means to increase LNF efficacy with minimal side effects. The modeling findings provide an important advance in understanding HDV dynamics and the basis to optimize LNF therapy for hepatitis D. (Hepatology Communications 2017;1:288-292).
View details for DOI 10.1002/hep4.1043
View details for Web of Science ID 000453170600002
View details for PubMedID 29404459
View details for PubMedCentralID PMC5721397
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Emerging concepts for the treatment of hepatitis delta.
Current opinion in virology
2017; 24: 55-59
Abstract
Hepatitis delta virus (HDV) causes the most severe form of human viral hepatitis and is associated with a higher risk of cirrhosis, liver decompensation and liver cancer. Interferon alpha is the only agent that has demonstrated efficacy to date, although response rates are low and it is associated with significant side effects. A better understanding of the relevant molecular virology has resulted in the identification of new candidate targets. Future therapeutic options are rapidly evolving as several new agents have entered clinical development, including the entry inhibitor myrcludex-B, the nucleic acid polymer REP2139-Ca inhibiting HBV surface antigen secretion, the farnesyltransferase inhibitor lonafarnib that targets virus assembly, and a better tolerated interferon-interferon lambda.
View details for DOI 10.1016/j.coviro.2017.04.004
View details for PubMedID 28475945
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The IFN-?-IFN-?R1-IL-10Rß Complex Reveals Structural Features Underlying Type III IFN Functional Plasticity.
Immunity
2017; 46 (3): 379-392
Abstract
Type III interferons (IFN-λs) signal through a heterodimeric receptor complex composed of the IFN-λR1 subunit, specific for IFN-λs, and interleukin-10Rβ (IL-10Rβ), which is shared by multiple cytokines in the IL-10 superfamily. Low affinity of IL-10Rβ for cytokines has impeded efforts aimed at crystallizing cytokine-receptor complexes. We used yeast surface display to engineer a higher-affinity IFN-λ variant, H11, which enabled crystallization of the ternary complex. The structure revealed that IL-10Rβ uses a network of tyrosine residues as hydrophobic anchor points to engage IL-10 family cytokines that present complementary hydrophobic binding patches, explaining its role as both a cross-reactive but cytokine-specific receptor. H11 elicited increased anti-proliferative and antiviral activities in vitro and in vivo. In contrast, engineered higher-affinity type I IFNs did not increase antiviral potency over wild-type type I IFNs. Our findings provide insight into cytokine recognition by the IL-10R family and highlight the plasticity of type III interferon signaling and its therapeutic potential.
View details for DOI 10.1016/j.immuni.2017.02.017
View details for PubMedID 28329704
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The IFN-lambda-IFN-lambda R1-IL-10R beta Complex Reveals Structural Features Underlying Type III IFN Functional Plasticity
IMMUNITY
2017; 46 (3): 379-392
Abstract
Type III interferons (IFN-λs) signal through a heterodimeric receptor complex composed of the IFN-λR1 subunit, specific for IFN-λs, and interleukin-10Rβ (IL-10Rβ), which is shared by multiple cytokines in the IL-10 superfamily. Low affinity of IL-10Rβ for cytokines has impeded efforts aimed at crystallizing cytokine-receptor complexes. We used yeast surface display to engineer a higher-affinity IFN-λ variant, H11, which enabled crystallization of the ternary complex. The structure revealed that IL-10Rβ uses a network of tyrosine residues as hydrophobic anchor points to engage IL-10 family cytokines that present complementary hydrophobic binding patches, explaining its role as both a cross-reactive but cytokine-specific receptor. H11 elicited increased anti-proliferative and antiviral activities in vitro and in vivo. In contrast, engineered higher-affinity type I IFNs did not increase antiviral potency over wild-type type I IFNs. Our findings provide insight into cytokine recognition by the IL-10R family and highlight the plasticity of type III interferon signaling and its therapeutic potential.
View details for DOI 10.1016/j.immuni.2017.02.017
View details for Web of Science ID 000396818100011
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Extracellular Matrix Functionalization and Huh-7.5 Cell Coculture Promote the Hepatic Differentiation of Human Adipose-Derived Mesenchymal Stem Cells in a 3D ICC Hydrogel Scaffold.
ACS biomaterials science & engineering
2016; 2 (12): 2255-2265
Abstract
In this study, we constructed a microporous hydrogel scaffold with hexagonally packed interconnected cavities and extracellular matrix (ECM)-functionalized interior surface, and systematically investigated the hepatic differentiation of human adipose-derived mesenchymal stem cells (hAD-MSCs) under the influence of three key factors: three-dimensional (3D) geometry, ECM presence, and coculture with hepatocyte-derived cell line. Results confirmed that (i) hepatic differentiation of hAD-MSC is more efficient in a 3D microporous scaffold than in 2D monolayer culture; (ii) the presence of both ECM components (fibronectin and collagen-I) in the scaffold is superior to collagen-I only, highlighting the importance of fibronectin; and (iii) coculture with Huh-7.5 hepatocyte-derived cells promoted liver-specific functions of the hAD-MSC-derived hepatocytes. The optimized differentiation process only took 21 days to complete, a time length that is shorter or at least comparable to previous reports, and more importantly, yielded an albumin production more than 10-fold higher than conventional 2D culture. Our approach of optimizing hAD-MSC hepatic differentiation could provide a potential solution to the challenges such as hepatocyte transplantation or the establishment of human physiologically relevant liver models in vitro.
View details for DOI 10.1021/acsbiomaterials.6b00487
View details for PubMedID 33465898
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Extracellular Matrix Functionalization and Huh-7.5 Cell Coculture Promote the Hepatic Differentiation of Human Adipose-Derived Mesenchymal Stem Cells in a 3D ICC Hydrogel Scaffold
ACS BIOMATERIALS SCIENCE & ENGINEERING
2016; 2 (12): 2255-2265
View details for DOI 10.1021/acsbiomaterials.6b00487
View details for Web of Science ID 000389789200015
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ECM proteins in a microporous scaffold influence hepatocyte morphology, function, and gene expression
SCIENTIFIC REPORTS
2016; 6
Abstract
It is well known that a three-dimensional (3D) culture environment and the presence of extracellular matrix (ECM) proteins facilitate hepatocyte viability and maintenance of the liver-specific phenotype in vitro. However, it is not clear whether specific ECM components such as collagen or fibronectin differentially regulate such processes, especially in 3D scaffolds. In this study, a series of ECM-functionalized inverted colloidal crystal (ICC) microporous scaffolds were fabricated and their influence on Huh-7.5 cell proliferation, morphology, hepatic-specific functions, and patterns of gene expression were compared. Both collagen and fibronectin promoted albumin production and liver-specific gene expression of Huh-7.5 cells, compared with the bare ICC scaffold. Interestingly, cells in the fibronectin-functionalized scaffold exhibited different aggregation patterns to those in the collagen-functionalized scaffold, a variation that could be related to the distinct mRNA expression levels of cell adhesion-related genes. Based on these results, we can conclude that different ECM proteins, such as fibronectin and collagen, indeed play distinct roles in the phenotypic regulation of cells cultured in a 3D environment.
View details for DOI 10.1038/srep37427
View details for PubMedID 27897167
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A novel quantitative microarray antibody capture (Q-MAC) assay identifies an extremely high HDV prevalence amongst HBV infected Mongolians.
Hepatology
2016
Abstract
Hepatitis delta virus (HDV) causes the most severe form of human viral hepatitis. HDV requires a hepatitis B virus (HBV) co-infection to provide HDV with HBV surface antigen envelope proteins. The net effect of HDV is to make the underlying HBV disease worse, including higher rates of hepatocellular carcinoma (HCC). Accurate assessments of current HDV prevalence have been hampered by the lack of readily available and reliable quantitative assays, combined with the absence of an FDA-approved therapy. We sought to develop a convenient assay for accurately screening populations and to use this assay to determine HDV prevalence in a population with abnormally high rates of HCC. We developed a high throughput quantitative microarray antibody capture (Q-MAC) assay for anti-HDV IgG wherein recombinant HDV delta antigen is printed by microarray on slides coated with a noncontinuous, nanostructured plasmonic gold film, enabling quantitative fluorescent detection of anti-HDV antibody in small aliquots of patient serum. This assay was then used to screen all HBV-infected patients identified in a large randomly selected cohort designed to represent the Mongolian population. We identified two quantitative thresholds of captured antibody that were 100% predictive of the sample either being positive on standard western blot, or harboring HDV RNA detectable by qPCR, respectively. Subsequent screening of the HBV-positive cohort revealed that a remarkable 57% were RNA positive and an additional 4% were positive on western blot alone.The Q-MAC assay's unique performance characteristics make it ideal for population screening. Its application to the Mongolian HBsAg+ population reveals an apparent ∼60% prevalence of HDV co-infection amongst these HBV-infected Mongolian subjects, which may help explain the extraordinarily high rate of HCC in Mongolia. This article is protected by copyright. All rights reserved.
View details for DOI 10.1002/hep.28957
View details for PubMedID 27880976
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Exploring Optimal Dosing Of Lonafarnib With Ritonavir For The Treatment Of Chronic Delta Hepatitis-Interim Results From The Lowr Hdv-2 Study
WILEY. 2016: 910A–911A
View details for Web of Science ID 000385493804206
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The Prenylation Inhibitor Lonafarnib Can Induce Post-Treatment Alt Flares With Viral Clearance In Patients With Chronic Delta Hepatitis
WILEY. 2016: 927A
View details for Web of Science ID 000385493804236
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Characterization of HDV and HBV kinetics during acute co-infection and interferon-alpha treatment in uPA/SCID chimeric mice with humanized livers
WILEY. 2016: 9A–10A
View details for Web of Science ID 000385493800019
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A Phase 2 Study Of Titrating-Dose Lonafarnib Plus Ritonavir In Patients With Chronic Hepatitis D: Interim Results From The Lonafarnib With Ritonavir In HDV-4 (LOWR HDV-4) Study
WILEY. 2016: 121A–122A
View details for Web of Science ID 000385493800231
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Reconstitution and Functional Analysis of a Full-Length Hepatitis C Virus NS5B Polymerase on a Supported Lipid Bilayer.
ACS central science
2016; 2 (7): 456-466
Abstract
Therapeutic targeting of membrane-associated viral proteins is complicated by the challenge of investigating their enzymatic activities in the native membrane-bound state. To permit functional characterization of these proteins, we hypothesized that the supported lipid bilayer (SLB) can support in situ reconstitution of membrane-associated viral protein complexes. As proof-of-principle, we selected the hepatitis C virus (HCV) NS5B polymerase which is essential for HCV genome replication, and determined that the SLB platform enables functional reconstitution of membrane protein activity. Quartz crystal microbalance with dissipation (QCM-D) monitoring enabled label-free detection of full-length NS5B membrane association, its interaction with replicase subunits NS3, NS5A, and template RNA, and most importantly its RNA synthesis activity. This latter activity could be inhibited by the addition of candidate small molecule drugs. Collectively, our results demonstrate that the SLB platform can support functional studies of membrane-associated viral proteins engaged in critical biological activities.
View details for DOI 10.1021/acscentsci.6b00112
View details for PubMedID 27504492
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Multistep Compositional Remodeling of Supported Lipid Membranes by Interfacially Active Phosphatidylinositol Kinases
ANALYTICAL CHEMISTRY
2016; 88 (10): 5042-5045
Abstract
The multienzyme catalytic phosphorylation of phosphatidylinositol (PI) in a supported lipid membrane platform is demonstrated for the first time. One-step treatment with PI 4-kinase IIIβ (PI4Kβ) yielded PI 4-phosphate (PI4P), while a multistep enzymatic cascade of PI4Kβ followed by PIP 5-kinase produced PI-4,5-bisphosphate (PI(4,5)P2 or PIP2). By employing quartz crystal microbalance with dissipation monitoring, we were able to track membrane association of kinase enzymes for the first time as well as detect PI4P and PI(4,5)P2 generation based on subsequent antibody binding to the supported lipid bilayers. Pharmacologic inhibition of PI4Kβ by a small molecule inhibitor was also quantitatively assessed, yielding an EC50 value that agrees well with conventional biochemical readout. Taken together, the development of a PI-containing supported membrane platform coupled with surface-sensitive measurement techniques for kinase studies opens the door to exploring the rich biochemistry and pharmacological targeting of membrane-associated phosphoinositides.
View details for DOI 10.1021/acs.analchem.6b01293
View details for PubMedID 27118725
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Profiling system-wide immune signaling in chronic viral infection and its response to viral clearance
AMER ASSOC IMMUNOLOGISTS. 2016
View details for Web of Science ID 000380288303330
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Parallel shRNA and CRISPR-Cas9 screens enable antiviral drug target identification
NATURE CHEMICAL BIOLOGY
2016; 12 (5): 361-?
Abstract
Broad-spectrum antiviral drugs targeting host processes could potentially treat a wide range of viruses while reducing the likelihood of emergent resistance. Despite great promise as therapeutics, such drugs remain largely elusive. Here we used parallel genome-wide high-coverage short hairpin RNA (shRNA) and clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 screens to identify the cellular target and mechanism of action of GSK983, a potent broad-spectrum antiviral with unexplained cytotoxicity. We found that GSK983 blocked cell proliferation and dengue virus replication by inhibiting the pyrimidine biosynthesis enzyme dihydroorotate dehydrogenase (DHODH). Guided by mechanistic insights from both genomic screens, we found that exogenous deoxycytidine markedly reduced GSK983 cytotoxicity but not antiviral activity, providing an attractive new approach to improve the therapeutic window of DHODH inhibitors against RNA viruses. Our results highlight the distinct advantages and limitations of each screening method for identifying drug targets, and demonstrate the utility of parallel knockdown and knockout screens for comprehensive probing of drug activity.
View details for DOI 10.1038/NCHEMBIO.2050
View details for PubMedID 27018887
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Design and Structural Characterization of Potent and Selective Inhibitors of Phosphatidylinositol 4 Kinase III beta
JOURNAL OF MEDICINAL CHEMISTRY
2016; 59 (5): 1830-1839
Abstract
Type III phosphatidylinositol 4-kinase (PI4KIIIβ) is an essential enzyme in mediating membrane trafficking and is implicated in a variety of pathogenic processes. It is a key host factor mediating replication of RNA viruses. The design of potent and specific inhibitors of this enzyme will be essential to define its cellular roles and may lead to novel antiviral therapeutics. We previously reported the PI4K inhibitor PIK93, and this compound has defined key functions of PI4KIIIβ. However, this compound showed high cross reactivity with class I and III PI3Ks. Using structure-based drug design, we have designed novel potent and selective (>1000-fold over class I and class III PI3Ks) PI4KIIIβ inhibitors. These compounds showed antiviral activity against hepatitis C virus. The co-crystal structure of PI4KIIIβ bound to one of the most potent compounds reveals the molecular basis of specificity. This work will be vital in the design of novel PI4KIIIβ inhibitors, which may play significant roles as antiviral therapeutics.
View details for DOI 10.1021/acs.jmedchem.5b01311
View details for Web of Science ID 000372043400012
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Design and Structural Characterization of Potent and Selective Inhibitors of Phosphatidylinositol 4 Kinase IIIß.
Journal of medicinal chemistry
2016; 59 (5): 1830-1839
Abstract
Type III phosphatidylinositol 4-kinase (PI4KIIIβ) is an essential enzyme in mediating membrane trafficking and is implicated in a variety of pathogenic processes. It is a key host factor mediating replication of RNA viruses. The design of potent and specific inhibitors of this enzyme will be essential to define its cellular roles and may lead to novel antiviral therapeutics. We previously reported the PI4K inhibitor PIK93, and this compound has defined key functions of PI4KIIIβ. However, this compound showed high cross reactivity with class I and III PI3Ks. Using structure-based drug design, we have designed novel potent and selective (>1000-fold over class I and class III PI3Ks) PI4KIIIβ inhibitors. These compounds showed antiviral activity against hepatitis C virus. The co-crystal structure of PI4KIIIβ bound to one of the most potent compounds reveals the molecular basis of specificity. This work will be vital in the design of novel PI4KIIIβ inhibitors, which may play significant roles as antiviral therapeutics.
View details for DOI 10.1021/acs.jmedchem.5b01311
View details for PubMedID 26885694
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Future Therapy for Hepatitis B Virus: Role of Immunomodulators.
Current hepatology reports
2016; 15 (4): 237-244
Abstract
Although currently available therapies for chronic hepatitis B virus infection can suppress viremia and provide long-term benefits for patients, they do not lead to a functional cure for most patients. Advances in our understanding of the virus-host interaction and the recent remarkable success of immunotherapy in cancer offer new and promising strategies for developing immune modulators that may become important components of a total therapeutic approach to hepatitis B, some of which are now in clinical development. Among the immunomodulatory agents currently being investigated to combat chronic HBV are toll-like receptor agonists, immune checkpoint inhibitors, therapeutic vaccines, and engineered T cells. The efficacy of some immune modulatory therapies is compromised by high viral antigen levels. Cutting edge strategies, including RNA interference and CRISPR/Cas9, are now being studied that may ultimately be shown to have the capacity to lower viral antigen levels sufficiently to substantially increase the efficacy of these agents. The current advances in therapies for chronic hepatitis B are leading us toward the possibility of a functional cure.
View details for PubMedID 27917363
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Decline in Hepatitis C Virus-related Liver Transplantation Waitlist Registrations among Patients without Hepatocellular Carcinoma: Early Effect of Direct-Acting Antivirals?
WILEY-BLACKWELL. 2015: 1397A
View details for Web of Science ID 000367013200030
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Oral prenylation inhibition with lonafarnib in chronic hepatitis D infection: a proof-of-concept randomised, double-blind, placebo-controlled phase 2A trial
LANCET INFECTIOUS DISEASES
2015; 15 (10): 1167-1174
Abstract
Therapies for chronic hepatitis delta virus (HDV) infection are unsatisfactory. Prenylation is essential for HDV and inhibition abrogates HDV production in experimental models. In a proof-of-concept study, we aimed to assess the effect on HDV RNA levels, safety, and tolerability of the prenylation inhibitor lonafarnib in patients with chronic delta hepatitis.In this phase 2A double-blind, randomised, placebo-controlled study, patients aged 18 years or older with chronic HDV infection were randomly assigned (3:1 in group 1 and 2:1 in group 2) to receive lonafarnib 100 mg (group 1) or lonafarnib 200 mg (group 2) twice daily for 28 days with 6 months' follow-up. Participants were randomised by random-number tables blocked in groups of four without stratification. Both groups enrolled six treatment participants and two placebo participants. Group 1 placebo patients received open-label lonafarnib as group 2 participants. The primary therapeutic endpoint was a decrease in HDV RNA viral titre in serum and the primary safety endpoint was the ability to tolerate the drug at the prescribed dose for the full 4-week duration, defined as drug discontinuation due to intolerance or grade 3/4 adverse events. This trial is registered with ClinicalTrials.gov, number NCT01495585.Between Jan 19, 2012, and April 28, 2014, 14 patients were enrolled, of whom eight were assigned to group 1 and six were assigned to group 2. At day 28, compared with placebo, mean log HDV RNA declines from baseline were -0·73 log IU/mL in group 1 (95% CI 0·17-1·31; p=0·03) and -1·54 log IU/mL in group 2 (1·21-1·93; p<0·0001). Lonafarnib serum concentrations correlated with HDV RNA change (r(2)=0·78, p<0·0001). Model fits show that hepatitis B surface antigen (HBsAg) remained stable after a short pharmacological delay (0·75 days [SE 0·24]), lonafarnib effectiveness in blocking HDV production was greater in group 2 than in group 1 (0·952 [SE 0·06] vs 0·739 [0·05], p<0·001), and the HDV half-life was 1·62 days (0·07). There was no evidence of virological resistance. Adverse events were mainly mild to moderate with group 1 patients experiencing diarrhoea in three patients (50%) and nausea in two patients (33%) and in group 2 with all patients (100%) experiencing nausea, diarrhoea, abdominal bloating, and weight loss greater than 2 kg (mean of 4 kg). No treatment discontinuations occurred in any treatment groups.Treatment of chronic HDV with lonafarnib significantly reduces virus levels. The decline in virus levels significantly correlated with serum drug levels, providing further evidence for the efficacy of prenylation inhibition in chronic HDV.National Institute of Diabetes and Digestive and Kidney Diseases and National Cancer Institute, National Institutes of Health, and Eiger Biopharmaceuticals Inc.
View details for DOI 10.1016/S1473-3099(15)00074-2
View details for Web of Science ID 000361854300027
View details for PubMedID 26189433
View details for PubMedCentralID PMC4700535
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Hepatitis D in Children
JOURNAL OF PEDIATRIC GASTROENTEROLOGY AND NUTRITION
2015; 61 (3): 271-281
Abstract
Hepatitis D virus (HDV) is an uncommon, defective, single-stranded circular RNA virus that is dependent on the hepatitis B virus' surface antigen envelope proteins for transmission. It is highly pathogenic and associated with high rates of progression to cirrhosis and associated complications. HDV continues to ravage endemic parts of Asia and Europe, and its prevalence in the United States, although low, has not decreased in frequency, despite universal hepatitis B virus vaccination, because of lack of testing and underrecognition. There are few reports on the prevalence and characteristics of HDV infection in the pediatric population. We present 2 patients with HDV infection at our institution; both were from eastern Europe and were treated with pegylated interferon-α. The present standard of care treatment for HDV yields suboptimal results, but insights into the virology of hepatitis D are stimulating the search for novel therapeutic approaches, particularly the development of prenylation inhibitors and viral entry inhibitors.
View details for DOI 10.1097/MPG.0000000000000859
View details for PubMedID 25988557
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Sofosbuvir and simeprevir combination therapy in the setting of liver transplantation and hemodialysis
TRANSPLANT INFECTIOUS DISEASE
2015; 17 (2): 275-278
Abstract
We report safety, tolerability, and 12-week sustained virologic response with half-standard dose sofosbuvir and standard-dose simeprevir combination therapy in a hepatitis C virus genotype 1a-infected liver transplant recipient on hemodialysis - uncharted territory for sofosbuvir-based therapy. The patient was a non-responder to prior treatment with pegylated interferon plus ribavirin. Sofosbuvir efficacy was maintained despite pill-splitting and administration of half-standard dose, 200 mg per day. No drug-drug interactions were noted with tacrolimus-based immunosuppression. Laboratory tests remained stable or improved during therapy. Our observation, if reproduced in a larger study, may lead to significant improvement in clinical outcomes and cost savings in this patient population.
View details for DOI 10.1111/tid.12348
View details for Web of Science ID 000352219400013
View details for PubMedID 25641426
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Phosphatidylinositol 4,5-Bisphosphate Is an HCV NS5A Ligand and Mediates Replication of the Viral Genome.
Gastroenterology
2015; 148 (3): 616-625
Abstract
Phosphoinositides (PIs) bind and regulate localization of proteins via a variety of structural motifs. PI 4,5-bisphosphate (PI[4,5]P2) interacts with and modulates the function of several proteins involved in intracellular vesicular membrane trafficking. We investigated interactions between PI(4,5)P2 and hepatitis C virus (HCV) nonstructural protein 5A (NS5A) and effects on the viral life cycle.We used a combination of quartz crystal microbalance, circular dichroism, molecular genetics, and immunofluorescence to study specific binding of PI(4,5)P2 by the HCV NS5A protein. We evaluated the effects of PI(4,5)P2 on the function of NS5A by expressing wild-type or mutant forms of Bart79I or FL-J6/JFH-5'C19Rluc2AUbi21 RNA in Huh7 cells. We also studied the effects of strategies designed to inhibit PI(4,5)P2 on HCV replication in these cells.The N-terminal amphipathic helix of NS5A bound specifically to PI(4,5)P2, inducing a conformational change that stabilized the interaction between NS5A and TBC1D20, which is required for HCV replication. A pair of positively charged residues within the amphipathic helix (the basic amino acid PI(4,5)P2 pincer domain) was required for PI(4,5)P2 binding and replication of the HCV-RNA genome. A similar motif was found to be conserved across all HCV isolates, as well as amphipathic helices of many pathogens and apolipoproteins.PI(4,5)P2 binds to HCV NS5A to promote replication of the viral RNA genome in hepatocytes. Strategies to disrupt this interaction might be developed to inhibit replication of HCV and other viruses.
View details for DOI 10.1053/j.gastro.2014.11.043
View details for PubMedID 25479136
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The interaction between the Hepatitis C proteins NS4B and NS5A is involved in viral replication.
Virology
2015; 475: 139-149
Abstract
Hepatitis C virus (HCV) replicates in membrane associated, highly ordered replication complexes (RCs). These complexes include viral and host proteins necessary for viral RNA genome replication. The interaction network among viral and host proteins underlying the formation of these RCs is yet to be thoroughly characterized. Here, we investigated the association between NS4B and NS5A, two critical RC components. We characterized the interaction between these proteins using fluorescence resonance energy transfer and a mammalian two-hybrid system. Specific tryptophan residues within the C-terminal domain (CTD) of NS4B were shown to mediate this interaction. Domain I of NS5A, was sufficient to mediate its interaction with NS4B. Mutations in the NS4B CTD tryptophan residues abolished viral replication. Moreover, one of these mutations also affected NS5A hyperphosphorylation. These findings provide new insights into the importance of the NS4B-NS5A interaction and serve as a starting point for studying the complex interactions between the replicase subunits.
View details for DOI 10.1016/j.virol.2014.10.021
View details for PubMedID 25462354
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HCV NS5A Inhibitors: The Devil Is in the Details
GASTROENTEROLOGY
2014; 147 (2): 273–77
View details for PubMedID 24976028
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Fialuridine Induces Acute Liver Failure in Chimeric TK-NOG Mice: A Model for Detecting Hepatic Drug Toxicity Prior to Human Testing.
PLoS medicine
2014; 11 (4)
View details for DOI 10.1371/journal.pmed.1001628
View details for PubMedID 24736310
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Fialuridine induces acute liver failure in chimeric TK-NOG mice: a model for detecting hepatic drug toxicity prior to human testing.
PLoS medicine
2014; 11 (4)
Abstract
Seven of 15 clinical trial participants treated with a nucleoside analogue (fialuridine [FIAU]) developed acute liver failure. Five treated participants died, and two required a liver transplant. Preclinical toxicology studies in mice, rats, dogs, and primates did not provide any indication that FIAU would be hepatotoxic in humans. Therefore, we investigated whether FIAU-induced liver toxicity could be detected in chimeric TK-NOG mice with humanized livers.Control and chimeric TK-NOG mice with humanized livers were treated orally with FIAU 400, 100, 25, or 2.5 mg/kg/d. The response to drug treatment was evaluated by measuring plasma lactate and liver enzymes, by assessing liver histology, and by electron microscopy. After treatment with FIAU 400 mg/kg/d for 4 d, chimeric mice developed clinical and serologic evidence of liver failure and lactic acidosis. Analysis of liver tissue revealed steatosis in regions with human, but not mouse, hepatocytes. Electron micrographs revealed lipid and mitochondrial abnormalities in the human hepatocytes in FIAU-treated chimeric mice. Dose-dependent liver toxicity was detected in chimeric mice treated with FIAU 100, 25, or 2.5 mg/kg/d for 14 d. Liver toxicity did not develop in control mice that were treated with the same FIAU doses for 14 d. In contrast, treatment with another nucleotide analogue (sofosbuvir 440 or 44 mg/kg/d po) for 14 d, which did not cause liver toxicity in human trial participants, did not cause liver toxicity in mice with humanized livers.FIAU-induced liver toxicity could be readily detected using chimeric TK-NOG mice with humanized livers, even when the mice were treated with a FIAU dose that was only 10-fold above the dose used in human participants. The clinical features, laboratory abnormalities, liver histology, and ultra-structural changes observed in FIAU-treated chimeric mice mirrored those of FIAU-treated human participants. The use of chimeric mice in preclinical toxicology studies could improve the safety of candidate medications selected for testing in human participants. Please see later in the article for the Editors' Summary.
View details for DOI 10.1371/journal.pmed.1001628
View details for PubMedID 24736310
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Enabling Autologous Human Liver Regeneration With Differentiated Adipocyte Stem Cells
CELL TRANSPLANTATION
2014; 23 (12): 1573-1584
Abstract
We developed a novel method for differentiating adipocyte-derived stem cells (ASCs) into hepatocyte-like cells (iHeps). ASCs are cultured as spherical cellular aggregates, and are then induced by culture in chemically defined media for a short time period to differentiate into spherical-culture iHeps (SCi-Heps). SCi-Heps have many of the in vitro functional properties of mature hepatocytes, and they can stably reconstitute functioning human liver in vivo in a murine model system, and implantation studies demonstrate that SCi-Heps have a very low malignant potential. All human liver regenerative procedures, including ultrasound-guided direct liver implantation, are scalable and appropriate for human clinical use. These methods can be used to achieve the major promise of regenerative medicine; it may now be possible to regenerate human liver using autologous stem cells obtained from a readily accessible tissue.
View details for DOI 10.3727/096368913X673432
View details for PubMedID 24148223
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Understanding hepatitis delta virus dynamics and antiviral efficacy of the prenylation inhibitor lonafarnib
WILEY-BLACKWELL. 2014: 317A
View details for Web of Science ID 000344483801168
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Prenylation inhibition with lonafarnib decreases hepatitis D levels in humans
WILEY-BLACKWELL. 2014: 1092A–1093A
View details for Web of Science ID 000344483804422
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The stanford institute for chemical biology.
ACS chemical biology
2013; 8 (9): 1860-1861
View details for DOI 10.1021/cb400641u
View details for PubMedID 24053754
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Coinfection with hepatitis B and D: Epidemiology, prevalence and disease in patients in Northern California
JOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY
2013; 28 (9): 1521-1525
Abstract
With no report on the overall prevalence and ramifications of hepatitis Delta virus (HDV) infection in the United States for more than two decades, the characteristics of chronic hepatitis B virus (CHB) patients coinfected with HDV, including clinical presentation, rate of hepatitis C virus tri-infection, and HDV viral load, were assessed.At California Pacific Medical Center, a retrospective chart review was conducted on all CHB patients.Of 1191 CHB patients, 499 had been tested for HDV, with 42 (8%) determined to be coinfected; half of these were also hepatitis C virus-infected. Cirrhosis was present in 73% of the coinfected, 80% of the tri-infected, but only 22% of the monoinfected. Twenty-nine patients (69%) were Caucasian non-Hispanic; 10 (24%) were Asians and Pacific Islanders. Of 39 patients for whom HBV-DNA quantification at time of HDV presentation was available, 22 (56%) had undetectable levels; four (10%) had levels > 100 000 IU/mL.HDV affects individuals of all ages and various ethnic groups. Although HBV viral loads are lower, rates of cirrhosis are higher in coinfected patients and higher still in the tri-infected. Our data support revising screening guidelines to advocate for all patients with HBV to be screened for HDV in order to both give the individual patient important information related to the possible need for treatment and to support the public health goal of reducing transmission by educating HDV-negative patients about the need for protection against superinfection and HDV-infected patients about the need to protect against transmission to others.
View details for DOI 10.1111/jgh.12217
View details for Web of Science ID 000323389700017
View details for PubMedID 23574043
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The Anti-Genomic (Negative) Strand of Hepatitis C Virus Is Not Targetable by shRNA
NATURE PUBLISHING GROUP. 2013: S75
View details for Web of Science ID 000319858400191
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Analogs design, synthesis and biological evaluation of peptidomimetics with potential anti-HCV activity
BIOORGANIC & MEDICINAL CHEMISTRY
2013; 21 (10): 2742-2755
Abstract
Two series of peptidomimetics were designed, prepared and evaluated for their anti-HCV activity. One series possesses a C-terminal carboxylate functionality. In the other series, the electrophilic vinyl sulfonate moiety was introduced as a novel class of HCV NS3/4A protease inhibitors. In vitro based studies were then performed to evaluate the efficacies of the inhibitors using Human hepatoma cells, with the vinyl sulfonate ester (10) in particular, found to have highly potent anti-HCV activity with an EC(50) = 0.296 μM. Finally, molecular modeling studies were performed through docking of the synthesized compounds in the HCV NS3/4A protease active site to assess their binding modes with the enzyme and gain further insight into their structure-activity relationships.
View details for DOI 10.1016/j.bmc.2013.03.017
View details for Web of Science ID 000318318700011
View details for PubMedID 23583031
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The anti-genomic (negative) strand of Hepatitis C Virus is not targetable by shRNA.
Nucleic acids research
2013; 41 (6): 3688-3698
Abstract
Hepatitis C Virus (HCV) and other plus-strand RNA viruses typically require the generation of a small number of negative genomes (20-100× lower than the positive genomes) for replication, making the less-abundant antigenome an attractive target for RNA interference(RNAi)-based therapy. Because of the complementarity of duplex short hairpin RNA/small interfering RNA (shRNA/siRNAs) with both genomic and anti-genomic viral RNA strands, and the potential of both shRNA strands to become part of the targeting complexes, preclinical RNAi studies cannot distinguish which viral strand is actually targeted in infected cells. Here, we addressed the question whether the negative HCV genome was bioaccessible to RNAi. We first screened for the most active shRNA molecules against the most conserved regions in the HCV genome, which were then used to generate asymmetric anti-HCV shRNAs that produce biologically active RNAi specifically directed against the genomic or antigenomic HCV sequences. Using this simple but powerful and effective method to screen for shRNA strand selectivity, we demonstrate that the antigenomic strand of HCV is not a viable RNAi target during HCV replication. These findings provide new insights into HCV biology and have important implications for the design of more effective and safer antiviral RNAi strategies seeking to target HCV and other viruses with similar replicative strategies.
View details for DOI 10.1093/nar/gkt068
View details for PubMedID 23396439
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Using Chimeric Mice with Humanized Livers to Predict Human Drug Metabolism and a Drug-Drug Interaction
JOURNAL OF PHARMACOLOGY AND EXPERIMENTAL THERAPEUTICS
2013; 344 (2): 388-396
Abstract
Interspecies differences in drug metabolism have made it difficult to use preclinical animal testing data to predict the drug metabolites or potential drug-drug interactions (DDIs) that will occur in humans. Although chimeric mice with humanized livers can produce known human metabolites for test substrates, we do not know whether chimeric mice can be used to prospectively predict human drug metabolism or a possible DDI. Therefore, we investigated whether they could provide a more predictive assessment for clemizole, a drug in clinical development for the treatment of hepatitis C virus (HCV) infection. Our results demonstrate, for the first time, that analyses performed in chimeric mice can correctly identify the predominant human drug metabolite before human testing. The differences in the rodent and human pathways for clemizole metabolism were of importance, because the predominant human metabolite was found to have synergistic anti-HCV activity. Moreover, studies in chimeric mice also correctly predicted that a DDI would occur in humans when clemizole was coadministered with a CYP3A4 inhibitor. These results demonstrate that using chimeric mice can improve the quality of preclinical drug assessment.
View details for DOI 10.1124/jpet.112.198697
View details for PubMedID 23143674
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An HCV IRES element regulates viral replication independent of translation
63rd Annual Meeting of the American-Association-for-the-Study-of-Liver-Diseases (AASLD)
WILEY-BLACKWELL. 2012: 706A–706A
View details for Web of Science ID 000310955602444
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Structural Map of a MicroRNA-122: Hepatitis C Virus Complex
JOURNAL OF VIROLOGY
2012; 86 (2): 1250-1254
Abstract
MicroRNA-122 (miR-122) enhances hepatitis C virus (HCV) fitness via targeting two sites in the 5'-untranslated region (UTR) of HCV. We used selective 2'-hydroxyl acylation analyzed by primer extension to resolve the HCV 5'-UTR's RNA secondary structure in the presence of miR-122. Nearly all nucleotides in miR-122 are involved in targeting the second site, beyond classic seed base pairings. These additional interactions enhance HCV replication in cell culture. To our knowledge, this is the first biophysical study of this complex to reveal the importance of 'tail' miR-122 nucleotide interactions.
View details for DOI 10.1128/JVI.06367-11
View details for PubMedID 22072754
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Simplified RNA secondary structure mapping by automation of SHAPE data analysis
NUCLEIC ACIDS RESEARCH
2011; 39 (22)
Abstract
SHAPE (Selective 2'-hydroxyl acylation analysed by primer extension) technology has emerged as one of the leading methods of determining RNA secondary structure at the nucleotide level. A significant bottleneck in using SHAPE is the complex and time-consuming data processing that is required. We present here a modified data collection method and a series of algorithms, embodied in a program entitled Fast Analysis of SHAPE traces (FAST), which significantly reduces processing time. We have used this method to resolve the secondary structure of the first ~900 nt of the hepatitis C virus (HCV) genome, including the entire core gene. We have also demonstrated the ability of SHAPE/FAST to detect the binding of a small molecule inhibitor to the HCV internal ribosomal entry site (IRES). In conclusion, FAST allows for high-throughput data processing to match the current high-throughput generation of data possible with SHAPE, reducing the barrier to determining the structure of RNAs of interest.
View details for DOI 10.1093/nar/gkr773
View details for PubMedID 21965531
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Using 'Humanized' TK-NOG mice to predict human drug metabolism and drug-drug interactions
17th North American Regional International-Society-for-the-Study-of-Xenobiotics (ISSX) Meeting
INFORMA HEALTHCARE. 2011: 164–165
View details for Web of Science ID 000297056400313
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Structural Linkage between Ligand Discrimination and Receptor Activation by Type I Interferons
CELL
2011; 146 (4): 621-632
Abstract
Type I Interferons (IFNs) are important cytokines for innate immunity against viruses and cancer. Sixteen human type I IFN variants signal through the same cell-surface receptors, IFNAR1 and IFNAR2, yet they can evoke markedly different physiological effects. The crystal structures of two human type I IFN ternary signaling complexes containing IFNα2 and IFNω reveal recognition modes and heterotrimeric architectures that are unique among the cytokine receptor superfamily but conserved between different type I IFNs. Receptor-ligand cross-reactivity is enabled by conserved receptor-ligand "anchor points" interspersed among ligand-specific interactions that "tune" the relative IFN-binding affinities, in an apparent extracellular "ligand proofreading" mechanism that modulates biological activity. Functional differences between IFNs are linked to their respective receptor recognition chemistries, in concert with a ligand-induced conformational change in IFNAR1, that collectively control signal initiation and complex stability, ultimately regulating differential STAT phosphorylation profiles, receptor internalization rates, and downstream gene expression patterns.
View details for DOI 10.1016/j.cell.2011.06.048
View details for PubMedID 21854986
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NOVEL ANTI-HCV THERAPY: SINGLE SHRNA TARGETING BOTH STRANDS OF HCV
WILEY-BLACKWELL. 2011: 418–19
View details for Web of Science ID 000297950900020
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The hepatitis C virus NS5A inhibitor (BMS-790052) alters the subcellular localization of the NS5A non-structural viral protein
VIROLOGY
2011; 414 (1): 10-18
Abstract
The hepatitis C virus (HCV) non-structural (NS) 5A protein plays an essential role in the replication of the viral RNA by the membrane-associated replication complex (RC). Recently, a putative NS5A inhibitor, BMS-790052, exhibited the highest potency of any known anti-HCV compound in inhibiting HCV replication in vitro and showed a promising clinical effect in HCV-infected patients. The precise mechanism of action for this new class of potential anti-HCV therapeutics, however, is still unclear. In order to gain further insight into its mode of action, we sought to test the hypothesis that the antiviral effect of BMS-790052 might be mediated by interfering with the functional assembly of the HCV RC. We observed that BMS-790052 indeed altered the subcellular localization and biochemical fractionation of NS5A. Taken together, our data suggest that NS5A inhibitors such as BMS-790052 can suppress viral genome replication by altering the proper localization of NS5A into functional RCs.
View details for DOI 10.1016/j.virol.2011.03.026
View details for PubMedID 21513964
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Role for ADP Ribosylation Factor 1 in the Regulation of Hepatitis C Virus Replication
JOURNAL OF VIROLOGY
2011; 85 (2): 946-956
Abstract
We hypothesized that ADP-ribosylation factor 1 (Arf1) plays an important role in the biogenesis and maintenance of infectious hepatitis C virus (HCV). Huh7.5 cells, in which HCV replicates and produces infectious viral particles, were exposed to brefeldin A or golgicide A, pharmacological inhibitors of Arf1 activation. Treatment with these agents caused a reduction in viral RNA levels, the accumulation of infectious particles within the cells, and a reduction in the levels of these particles in the extracellular medium. Fluorescence analyses showed that the viral nonstructural (NS) proteins NS5A and NS3, but not the viral structural protein core, shifted their localization from speckle-like structures in untreated cells to the rims of lipid droplets (LDs) in treated cells. Using pulldown assays, we showed that ectopic overexpression of NS5A in Huh7 cells reduces the levels of GTP-Arf1. Downregulation of Arf1 expression by small interfering RNA (siRNA) decreased both the levels of HCV RNA and the production of infectious viral particles and altered the localization of NS5A to the peripheries of LDs. Together, our data provide novel insights into the role of Arf1 in the regulation of viral RNA replication and the production of infectious HCV.
View details for DOI 10.1128/JVI.00753-10
View details for Web of Science ID 000285554300030
View details for PubMedID 21068255
View details for PubMedCentralID PMC3020004
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NS4B Targets and Inhibitors
HEPATITIS C: ANTIVIRAL DRUG DISCOVERY AND DEVELOPMENT
2011: 257–69
View details for Web of Science ID 000289380100014
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Mixing the right hepatitis C inhibitor cocktail
TRENDS IN MOLECULAR MEDICINE
2011; 17 (1): 34-46
Abstract
Therapy for hepatitis C virus (HCV) infection is on the cusp of a new era. Until now, standard-of-care therapy has involved interferon (IFN) and ribavirin. With the first successful Phase III trials of specific targeted antiviral therapy for HCV (STAT-C) compounds, as well as three trials in progress giving the first glimpse of IFN-free combinations of STAT-C agents, this review looks ahead to the new classes of anti-HCV agents currently in clinical development. Successful pharmacologic control of HIV and TB frames the discussion, as well as consideration of the mutation frequency of HCV replication. Maximizing synergy between agents and minimizing cumulative toxicity will be critical to the design of future IFN-free STAT-C regimens.
View details for DOI 10.1016/j.molmed.2010.10.005
View details for Web of Science ID 000287340500005
View details for PubMedCentralID PMC3085044
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Hydrophobic nanoparticles improve permeability of cell-encapsulating poly(ethylene glycol) hydrogels while maintaining patternability
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
2010; 107 (48): 20709-20714
Abstract
Cell encapsulating poly(ethylene glycol) hydrogels represent a promising approach for constructing 3D cultures designed to more closely approximate in vivo tissue environment. Improved strategies are needed, however, to optimally balance hydrogel permeability to support metabolic activities of encapsulated cells, while maintaining patternability to restore key aspects of tissue architecture. Herein, we have developed one such strategy incorporating hydrophobic nanoparticles to partially induce looser cross-linking density at the particle-hydrogel interface. Strikingly, our network design significantly increased hydrogel permeability, while only minimally affecting the matrix mechanical strength or prepolymer viscosity. This structural advantage improved viability and functions of encapsulated cells and permitted micron-scale structures to control over spatial distribution of incorporated cells. We expect that this design strategy holds promise for the development of more advanced artificial tissues that can promote high levels of cell metabolic activity and recapitulate key architectural features.
View details for DOI 10.1073/pnas.1005211107
View details for PubMedID 21071674
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Mixing the right hepatitis C inhibitor cocktail.
Trends in molecular medicine
2010
Abstract
Therapy for hepatitis C virus (HCV) infection is on the cusp of a new era. Until now, standard-of-care therapy has involved interferon (IFN) and ribavirin. With the first successful Phase III trials of specific targeted antiviral therapy for HCV (STAT-C) compounds, as well as three trials in progress giving the first glimpse of IFN-free combinations of STAT-C agents, this review looks ahead to the new classes of anti-HCV agents currently in clinical development. Successful pharmacologic control of HIV and TB frames the discussion, as well as consideration of the mutation frequency of HCV replication. Maximizing synergy between agents and minimizing cumulative toxicity will be critical to the design of future IFN-free STAT-C regimens.
View details for DOI 10.1016/j.molmed.2010.10.005
View details for PubMedID 21106440
View details for PubMedCentralID PMC3085044
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The Future of HCV Therapy: NS4B as an Antiviral Target
VIRUSES-BASEL
2010; 2 (11): 2481-2492
Abstract
Chronic hepatitis C virus (HCV) infection is a major worldwide cause of liver disease, including cirrhosis and hepatocellular carcinoma. It is estimated that more than 170 million individuals are infected with HCV, with three to four million new cases each year. The current standard of care, combination treatment with interferon and ribavirin, eradicates the virus in only about 50% of chronically infected patients. Notably, neither of these drugs directly target HCV. Many new antiviral therapies that specifically target hepatitis C (e.g. NS3 protease or NS5B polymerase inhibitors) are therefore in development, with a significant number having advanced into clinical trials. The nonstructural 4B (NS4B) protein, is among the least characterized of the HCV structural and nonstructural proteins and has been subjected to few pharmacological studies. NS4B is an integral membrane protein with at least four predicted transmembrane (TM) domains. A variety of functions have been postulated for NS4B, such as the ability to induce the membranous web replication platform, RNA binding and NTPase activity. This review summarizes potential targets within the nonstructural protein NS4B, with a focus on novel classes of NS4B inhibitors.
View details for DOI 10.3390/v2112481
View details for PubMedID 21157574
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STRUCTURAL INSIGHTS INTO THE MECHANISM OF MICRORNA-MODULATED HCV TRANSLATION
61st Annual Meeting of the American-Association-for-the-Study-of-Liver-Diseases
WILEY-BLACKWELL. 2010: 816A–817A
View details for Web of Science ID 000288775601345
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IDENTIFICATION AND TARGETING OF VIRAL-HOST PROTEIN-PROTEIN INTERACTIONS USING A NOVEL MICROFLUIDICS AFFINITY ASSAY
WILEY-BLACKWELL. 2010: 743A
View details for Web of Science ID 000288775601199
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Prevalence, Correlates, and Viral Dynamics of Hepatitis Delta among Injection Drug Users
JOURNAL OF INFECTIOUS DISEASES
2010; 202 (6): 845-852
Abstract
Most hepatitis delta virus (HDV) prevalence estimates from the United States are >10 years old, and HDV has shown significant temporal variation in other populations. HDV-hepatitis B virus (HBV) dual infection progresses rapidly, has more complications, and has a different treatment regimen than HBV infection alone. Accurate estimates of prevalence and risk factors are important to help clinicians decide who to screen.Injection drug users in Baltimore, Maryland, who were positive for HBV serologic markers were tested for hepatitis delta antibody (HDAb) at 2 time periods: 1988-1989 (194 participants) and 2005-2006 (258 participants). Those who were HDAb positive in 2005-2006, plus a random sample of HDAb negative, HBV-positive participants were tested for HDV RNA, HBV DNA, and HCV RNA. Characteristics associated with HDV exposure and viremia were identified.HDV prevalence declined from 15% in 1988-1989 to 11% in 2005-2006. Among those with chronic HBV infection, prevalence increased from 29% (14 of 48 participants) to 50% (19 of 38 participants) (P=.05). Visiting a "shooting gallery" (a location where people gather to inject illegal drugs) was a strong correlate of HDAb positivity (relative risk, 3.08; P=.01). Eight (32%) of those who were HDAb positive had HDV viremia. Viremic participants had elevated liver enzyme levels and more emergency room visits.The temporal increase in HDV prevalence among those with chronic HBV infection is troubling; understanding this change should be a priority to prevent the burden from increasing.
View details for DOI 10.1086/655808
View details for Web of Science ID 000281091200004
View details for PubMedID 20701536
View details for PubMedCentralID PMC2924454
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Transdifferentiation of adipose-derived stem cells into hepatocytes: a new approach
LIVER INTERNATIONAL
2010; 30 (6): 913-922
Abstract
Several studies have demonstrated techniques in differentiating human adipose-derived stem cells (hADSCs) into hepatocytes. Unfortunately, transdifferentiation is inefficient, and the function of these induced hepatocyte-like cells (which we termed 'iHeps') is low compared with that of real hepatocytes.We aimed to identify transcriptional deficiencies in iHeps that are critical to hepatocyte development, which may provide insights into improving the efficiency of transdifferentiation.hADSCs were differentiated into iHeps, and iHeps were assayed for hepatocyte-like activity. iHeps were then screened for expression of several growth factors, receptors and transcription factors (TFs) critical to liver development using reverse transcription-polymerase chain reaction (RT-PCR). Deficient TFs were transduced into hADSCs and hepatocyte function was reassessed after hepatic differentiation.Differentiation of hADSCs into iHeps resulted in the upregulation of hepatic proteins. However, the levels of expression of hepatocyte-specific proteins in these iHeps were well below those of Huh 7.5 hepatoma cells, used in comparison. Five developmental TFs were notably absent on the RT-PCR screen. Lentiviral transduction of these TFs into hADSCs followed by culture in hepatocyte induction medium resulted in increased albumin expression compared with untransduced hADSCs treated in a parallel fashion.These five missing TFs are known to regulate hepatocyte differentiation and some are required to establish the competence of the foregut endoderm. Presumably due to their mesenchymal lineage, hADSCs do not express these endodermal TFs and are not fully competent to respond to critical developmental signals. Supplementation of these TFs may induce competency and enhance the differentiation of hADSCs into hepatocytes.
View details for DOI 10.1111/j.1478-3231.2010.02231.x
View details for PubMedID 20353420
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The Hepatitis C Virus (HCV) NS4B RNA Binding Inhibitor Clemizole Is Highly Synergistic with HCV Protease Inhibitors
Annual Meeting of the Infectious-Diseases-Society-of-America
OXFORD UNIV PRESS INC. 2010: 65–74
Abstract
We recently identified a compound, clemizole hydrochloride, that inhibits NS4B's RNA binding and hepatitis C virus (HCV) replication. Although significant, clemizole's antiviral effect is moderate (50% effective concentration of 8 microM against an HCV genotype 2a clone). We hypothesized that the combination of clemizole with other anti-HCV agents can increase the antiviral effect over that achieved with each drug alone and could also decrease the emergence of viral resistance.Luciferase reporter-linked HCV replication assays were used to study the antiviral effects of drug combinations that included clemizole. Data were analyzed using Loewe additivity and Bliss independence models for synergy, and resistance studies were performed using HCV colony formation assays.Clemizole's antiviral effect was highly synergistic with the HCV protease inhibitors SCH503034 and VX950, without toxicity. In contrast, combinations of clemizole with either interferon, ribavirin, or the nucleoside (NM283) and nonnucleoside (HCV796) HCV polymerase inhibitors were additive. Furthermore, combination of clemizole with SCH503034 decreased the frequency of drug-resistant mutants, compared with treatment with either drug alone. Finally, no cross-resistance to clemizole of SCH503034-resistant mutants (or vice versa) was observed.Clemizole can yield high-level synergy with the protease inhibitor class. Inclusion of clemizole in future anti-HCV cocktails can represent an attractive paradigm for increasing current virologic response rates.
View details for DOI 10.1086/653080
View details for Web of Science ID 000278322300008
View details for PubMedCentralID PMC3008401
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A small molecule inhibits HCV replication and alters NS4B's subcellular distribution
ANTIVIRAL RESEARCH
2010; 87 (1): 1-8
Abstract
Hepatitis C Virus (HCV) is a leading cause of liver disease and represents a significant public health challenge. Treatments for this disease are inadequate and improved antiviral therapies are necessary. Several such antivirals are in development, most of which target the well-characterized NS3 protease or the NS5B polymerase. In contrast, the nonstructural 4B (NS4B) protein, though essential for HCV RNA replication, has been the subject of few pharmacological studies. One of the functions ascribed to this protein is the ability to form intracellular membrane-associated foci (MAF), which are believed to be related to the sites of viral replication. Here, we report the identification of a small molecule that inhibits HCV replication and disrupts the organization of these MAF. Genetic analysis links the compound's mode of action to the NS4B gene product, and transient transfections of NS4B-GFP demonstrate that treatment with this compound can lead to the formation of novel elongated assemblies of NS4B. Furthermore, an in vitro dynamic light scattering assay provides evidence that the second amphipathic helix of NS4B may be the target of the drug. Our results demonstrate that this molecule represents a new potential class of HCV inhibitors and also provides us with a useful tool for studying the HCV life cycle.
View details for DOI 10.1016/j.antiviral.2010.03.013
View details for PubMedID 20363257
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The hepatitis C virus (HCV) NS4B RNA binding inhibitor clemizole is highly synergistic with HCV protease inhibitors.
journal of infectious diseases
2010; 202 (1): 65-74
Abstract
We recently identified a compound, clemizole hydrochloride, that inhibits NS4B's RNA binding and hepatitis C virus (HCV) replication. Although significant, clemizole's antiviral effect is moderate (50% effective concentration of 8 microM against an HCV genotype 2a clone). We hypothesized that the combination of clemizole with other anti-HCV agents can increase the antiviral effect over that achieved with each drug alone and could also decrease the emergence of viral resistance.Luciferase reporter-linked HCV replication assays were used to study the antiviral effects of drug combinations that included clemizole. Data were analyzed using Loewe additivity and Bliss independence models for synergy, and resistance studies were performed using HCV colony formation assays.Clemizole's antiviral effect was highly synergistic with the HCV protease inhibitors SCH503034 and VX950, without toxicity. In contrast, combinations of clemizole with either interferon, ribavirin, or the nucleoside (NM283) and nonnucleoside (HCV796) HCV polymerase inhibitors were additive. Furthermore, combination of clemizole with SCH503034 decreased the frequency of drug-resistant mutants, compared with treatment with either drug alone. Finally, no cross-resistance to clemizole of SCH503034-resistant mutants (or vice versa) was observed.Clemizole can yield high-level synergy with the protease inhibitor class. Inclusion of clemizole in future anti-HCV cocktails can represent an attractive paradigm for increasing current virologic response rates.
View details for DOI 10.1086/653080
View details for PubMedID 20486856
View details for PubMedCentralID PMC3008401
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Development of novel therapies for hepatitis C
ANTIVIRAL RESEARCH
2010; 86 (1): 79-92
Abstract
The current standard of care for the treatment of hepatitis C virus (HCV) infection is a combination of pegylated IFN and ribavirin (Peg-IFN/RBV). Because of the adverse effects associated with both IFN and ribavirin and because Peg-IFN/RBV provides only about a 45-50% sustained virological response (SVR, undetectable HCV RNA for greater than 24 weeks after cessation of therapy) in genotype 1-infected individuals, there is a need for more potent anti-HCV compounds with fewer adverse effects. The twenty-first International Conference on Antiviral Research held in May 2009 in Miami Beach, Florida, featured a special session focused on novel targets for HCV therapy. The session included presentations by world-renowned experts in HCV virology and covered a diverse array of potential targets for the development of new classes of HCV therapies. This review contains concise summaries of discussed topics that included the innate immune response, virus entry, the NS2 protease, the NS3 helicase, NS4B, and NS5A. Each presenter discussed the current knowledge of these targets and provided examples of recent scientific breakthroughs that are enhancing our understanding of these targets. As our understanding of the role of these novel anti-HCV targets increases so will our ability to discover new, more safe and effective anti-HCV therapies.
View details for DOI 10.1016/j.antivira1.2010.02.003
View details for Web of Science ID 000277809600148
View details for PubMedID 20417376
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Six RNA Viruses and Forty-One Hosts: Viral Small RNAs and Modulation of Small RNA Repertoires in Vertebrate and Invertebrate Systems
PLOS PATHOGENS
2010; 6 (2)
Abstract
We have used multiplexed high-throughput sequencing to characterize changes in small RNA populations that occur during viral infection in animal cells. Small RNA-based mechanisms such as RNA interference (RNAi) have been shown in plant and invertebrate systems to play a key role in host responses to viral infection. Although homologs of the key RNAi effector pathways are present in mammalian cells, and can launch an RNAi-mediated degradation of experimentally targeted mRNAs, any role for such responses in mammalian host-virus interactions remains to be characterized. Six different viruses were examined in 41 experimentally susceptible and resistant host systems. We identified virus-derived small RNAs (vsRNAs) from all six viruses, with total abundance varying from "vanishingly rare" (less than 0.1% of cellular small RNA) to highly abundant (comparable to abundant micro-RNAs "miRNAs"). In addition to the appearance of vsRNAs during infection, we saw a number of specific changes in host miRNA profiles. For several infection models investigated in more detail, the RNAi and Interferon pathways modulated the abundance of vsRNAs. We also found evidence for populations of vsRNAs that exist as duplexed siRNAs with zero to three nucleotide 3' overhangs. Using populations of cells carrying a Hepatitis C replicon, we observed strand-selective loading of siRNAs onto Argonaute complexes. These experiments define vsRNAs as one possible component of the interplay between animal viruses and their hosts.
View details for DOI 10.1371/journal.ppat.1000764
View details for PubMedID 20169186
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Identification of a Class of HCV Inhibitors Directed Against the Nonstructural Protein NS4B
SCIENCE TRANSLATIONAL MEDICINE
2010; 2 (15)
Abstract
New classes of drugs are needed to combat hepatitis C virus (HCV), an important worldwide cause of liver disease. We describe an activity of a key domain, an amphipathic helix we termed 4BAH2, within a specific HCV nonstructural protein, NS4B. In addition to its proposed role in viral replication, we validate 4BAH2 as essential for HCV genome replication and identify first-generation small-molecule inhibitors of 4BAH2 that specifically prevent HCV replication within cells. Mechanistic studies reveal that the inhibitors target 4BAH2 function by preventing either 4BAH2 oligomerization or 4BAH2 membrane association. 4BAH2 inhibitors represent an additional class of compounds with potential to effectively treat HCV.
View details for DOI 10.1126/scitranslmed.3000331
View details for PubMedID 20371471
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THE EVOLUTION OF HEPATITIS C VIRUS INNATE IMMUNE EVASION
Western Regional Meeting of the American-Federation-for-Medical-Research
LIPPINCOTT WILLIAMS & WILKINS. 2010: 180–80
View details for Web of Science ID 000273638400281
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Mechanism of an Amphipathic alpha-Helical Peptide's Antiviral Activity Involves Size-Dependent Virus Particle Lysis
ACS CHEMICAL BIOLOGY
2009; 4 (12): 1061-1067
Abstract
The N-terminal region of the hepatitis C virus (HCV) nonstructural protein NS5A contains an amphipathic alpha-helix that is necessary and sufficient for NS5A membrane association. A synthetic peptide (AH) comprising this amphipathic helix is able to lyse lipid vesicles that serve as a model system for virus particles. Based on quartz crystal microbalance-dissipation (QCM-D) experiments, the degree of vesicle rupturing was found to be inversely related to vesicle size, with maximal activity in the size range of several medically important viruses. In order to confirm and further study vesicle rupture, dynamic light scattering (DLS) and atomic force microscopy (AFM) experiments were also performed. The size dependence of vesicle rupturing helps explain the peptide's observed effect on the infectivity of a wide range of viruses. Further, in vitro studies demonstrated that AH peptide treatment significantly decreased the infectivity of HCV particles. Thus, the AH peptide might be used to rupture HCV particles extra-corporally (for HCV prevention) and within infected individuals (for HCV therapy).
View details for DOI 10.1021/cb900149b
View details for PubMedID 19928982
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The reliable targeting of specific drug release profiles by integrating arrays of different albumin-encapsulated microsphere types
BIOMATERIALS
2009; 30 (34): 6648-6654
Abstract
Biodegradable polymer microspheres have been successfully utilized as a medium for controlled protein or peptide-based drug release. Because the release kinetics has been typically controlled by modulating physical or chemical properties of the medium, these parameters must be optimized to obtain a specific release profile. However, due to the complexity of the release mechanism and the complicated interplay between various design parameters of the release medium, detailed prediction of the resulting release profile is a challenge. Herein we suggest a simple method to target specific release profiles more efficiently by integrating release profiles for an array of different microsphere types. This scheme is based on our observation that the resulting release profile from a mixture of different samples can be predicted as the linear summation of the individually measured release profiles of each sample. Hence, by employing a linear equation at each time point and formulating them as a matrix equation, we could determine how much of each microsphere type to include in a mixture in order to have a specific release profile. In accordance with this method, several targeted release profiles were successfully obtained. We expect that the proposed method will allow us to overcome limitations in controlling complicated release mechanisms so that drug delivery systems can be reliably designed to satisfy clinical demands.
View details for DOI 10.1016/j.biomaterials.2009.08.035
View details for PubMedID 19775742
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The Anti-Hepatitis C Agent Nitazoxanide Induces Phosphorylation of Eukaryotic Initiation Factor 2 alpha Via Protein Kinase Activated by Double-Stranded RNA Activation
GASTROENTEROLOGY
2009; 137 (5): 1827-1835
Abstract
New therapies are needed to treat patients infected with hepatitis C virus (HCV), a major worldwide cause of chronic liver disease. Nitazoxanide (NTZ), originally used to treat cryptosporidiosis infection, recently was shown to have unexpected antiviral activity in the HCV replicon system and in chronically infected patients. A pilot clinical study suggested that NTZ can augment the antiviral effect of interferon (IFN), although the molecular basis for its effect was unknown.We analyzed the effects of NTZ on the regulation of eukaryotic initiation factor-2alpha (eIF2alpha) and its IFN-induced kinase, protein kinase activated by double-stranded RNA (PKR), in cells that support HCV RNA replication and in vitro biochemical assays.NTZ increased eIF2alpha phosphorylation, a modification known to mediate host cell antiviral defenses. The addition of IFN to cell cultures increased NTZ-induced eIF2alpha phosphorylation. NTZ also increased PKR phosphorylation. In vitro, NTZ promoted PKR autophosphorylation, a key step in activating PKR's kinase activity for eIF2alpha. Finally, NTZ-induced eIF2alpha phosphorylation was reduced in the presence of specific inhibitors of PKR autophosphorylation.An important mechanism of NTZ's action involves activation of PKR, a key kinase that regulates the cell's innate antiviral response. These observations could explain the clinical antiviral effect of NTZ. NTZ might represent a new class of small molecules capable of potentiating and recapitulating important antiviral effects of IFN.
View details for DOI 10.1053/j.gastro.2009.07.056
View details for PubMedID 19664635
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DIFFERENTIATION OF HUMAN ADIPOSE TISSUE STEM CELLS INTO HEPATOCYTES: ROOM FOR IMPROVEMENT
JOHN WILEY & SONS INC. 2009: 902A
View details for Web of Science ID 000270456001289
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The Effect of Donor Race on the Survival of Black Americans Undergoing Liver Transplantation for Chronic Hepatitis C
LIVER TRANSPLANTATION
2009; 15 (9): 1126-1132
Abstract
The purpose of this study was to determine the effect of donor race on the outcome of black patients with chronic hepatitis C infection who undergo liver transplantation. The records for deceased donor liver transplants that occurred in the United States between January 1998 and December 2007 were obtained from the United Network for Organ Sharing. 26,212 records contained sufficient data to be included in the analysis. Of these, 11,989 (45.7%) records were for patients positive for hepatitis C virus (HCV) and 1292 (4.9%) were for patients both HCV-positive and black. Black recipients with white donors were found to have significantly worse outcomes than all other recipient-donor race combinations (P < 0.001). The crude 5-year survival rate for black recipients who had a black donor was 14% higher than the 5-year survival rate for black recipients who had a white donor. Multivariate regression analysis determined that a graft from a race-unmatched donor was an independent risk factor for graft failure (hazard ratio = 1.41, 95% confidence interval = 1.11-1.79) among HCV-positive black recipients but not among HCV-negative black recipients after adjustments for donor age, recipient age, cold ischemia time, serum creatinine, serum bilirubin, diabetes mellitus, body mass index, and donor cytomegalovirus status. The observation that race-unmatched grafts are a risk factor in HCV-positive black recipients, but not in HCV-negative black recipients, suggests an alteration of the graft-host relationship by HCV. In conclusion, our results suggest that HCV-positive black recipients who undergo liver transplantation can have increased graft survival if their donors are black, with survival rates approaching those of white liver transplant recipients.
View details for DOI 10.1002/lt.21835
View details for PubMedID 19718638
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The Evolution of the Major Hepatitis C Genotypes Correlates with Clinical Response to Interferon Therapy
PLOS ONE
2009; 4 (8)
Abstract
Patients chronically infected with hepatitis C virus (HCV) require significantly different durations of therapy and achieve substantially different sustained virologic response rates to interferon-based therapies, depending on the HCV genotype with which they are infected. There currently exists no systematic framework that explains these genotype-specific response rates. Since humans are the only known natural hosts for HCV-a virus that is at least hundreds of years old-one possibility is that over the time frame of this relationship, HCV accumulated adaptive mutations that confer increasing resistance to the human immune system. Given that interferon therapy functions by triggering an immune response, we hypothesized that clinical response rates are a reflection of viral evolutionary adaptations to the immune system.We have performed the first phylogenetic analysis to include all available full-length HCV genomic sequences (n = 345). This resulted in a new cladogram of HCV. This tree establishes for the first time the relative evolutionary ages of the major HCV genotypes. The outcome data from prospective clinical trials that studied interferon and ribavirin therapy was then mapped onto this new tree. This mapping revealed a correlation between genotype-specific responses to therapy and respective genotype age. This correlation allows us to predict that genotypes 5 and 6, for which there currently are no published prospective trials, will likely have intermediate response rates, similar to genotype 3. Ancestral protein sequence reconstruction was also performed, which identified the HCV proteins E2 and NS5A as potential determinants of genotype-specific clinical outcome. Biochemical studies have independently identified these same two proteins as having genotype-specific abilities to inhibit the innate immune factor double-stranded RNA-dependent protein kinase (PKR).An evolutionary analysis of all available HCV genomes supports the hypothesis that immune selection was a significant driving force in the divergence of the major HCV genotypes and that viral factors that acquired the ability to inhibit the immune response may play a role in determining genotype-specific response rates to interferon therapy.
View details for DOI 10.1371/journal.pone.0006579
View details for PubMedID 19668364
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Alpha-Helical Peptide-Induced Vesicle Rupture Revealing New Insight into the Vesicle Fusion Process As Monitored in Situ by Quartz Crystal Microbalance-Dissipation and Reflectometry
ANALYTICAL CHEMISTRY
2009; 81 (12): 4752-4761
Abstract
We have used simultaneous quartz crystal microbalance-dissipation (QCM-D) monitoring and four-detector optical reflectometry to monitor in situ the structural transformation of intact vesicles to a lipid bilayer on a gold surface. The structural transformation of lipid vesicles to a bilayer was achieved by introducing a particular amphipathic, alpha-helical (AH) peptide. The combined experimental apparatus allows us to simultaneously follow the acoustic and optical property changes of the vesicle rupturing process upon interaction with AH peptides. While QCM-D and reflectometry have similar sensitivities in terms of mass and thickness resolution, there are unique advantages in operating these techniques simultaneously on the same substrate. These advantages permit us to (1) follow the complex interaction between AH peptides and intact vesicles with both acoustic and optical mass measurements, (2) calculate the amount of dynamically coupled water during the interaction between AH peptides and intact vesicles, (3) demonstrate that the unexpectedly large increase of both adsorbed mass and the film's energy dissipation is mainly caused by swelling of the vesicles during the binding interaction with AH peptides, and (4) permit us to understand the structural transformation from intact vesicles to a bilayer via the AH peptide interaction by monitoring viscoelastic properties, acoustic mass, optical mass, and thickness changes of both the binding and destabilization processes. From the deduced "hydration signature" we followed the complex transformation of lipid assemblies. On the basis of this information, a mechanism of this structural transformation is proposed that provides new insight into the process of vesicle fusion on solid substrates.
View details for DOI 10.1021/ac900242s
View details for PubMedID 19459601
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AAV Based RNAi Therapies To Treat and/or Prevent HCV in Animal Models
NATURE PUBLISHING GROUP. 2009: S14
View details for Web of Science ID 000278019800035
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Mechanisms of HCV survival in the host
NATURE REVIEWS GASTROENTEROLOGY & HEPATOLOGY
2009; 6 (4): 217-227
Abstract
HCV infection is an important cause of liver disease worldwide-nearly 80% of infected patients develop chronic liver disease, which leads to the development of liver cirrhosis and hepatocellular carcinoma. The ability of HCV to persist within a host is believed to be related to the numerous mechanisms by which it evades the immune response of the host. These mechanisms can be divided into defensive and offensive strategies. Examples of defensive mechanisms include replication within enclosed structures, which provides protection from the host's antiviral defenses, genetic diversity created by inaccurate replication, which yields mutants resistant to the cell's antiviral strategies, and association of the virion with protective lipoproteins. Offensive mechanisms include virally encoded proteins and other factors that disrupt the ability of the host cells to detect the virus and downregulate its ability to respond to interferon, impair innate immune defense mechanisms and alter T-cell responses, and prevent the development of an effective B-cell-mediated humoral response. Greater understanding of these viral survival strategies will ultimately translate into more effective antiviral therapies and better prognosis for patients.
View details for DOI 10.1038/nrgastro.2009.32
View details for Web of Science ID 000265854200009
View details for PubMedID 19347013
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Viral infection of human progenitor and liver-derived cells encapsulated in three-dimensional PEG-based hydrogel
BIOMEDICAL MATERIALS
2009; 4 (1)
Abstract
We have studied the encapsulation of human progenitor cells into 3D PEG hydrogels. Replication-incompetent lentivirus promoter reporter vectors were found to efficiently detect the in vivo expression of human hepatic genes in hydrogel-encapsulated liver progenitor cells. Similarly, hydrogel-encapsulated cells could be efficiently infected with hepatitis C virus, and progeny infectious virus could be recovered from the media supernatants of the hydrogels. Provocatively, the diameters of these virus particles range from approximately 50 to 100 nm, while the calculated mesh size of the 8 k hydrogel is 44.6 +/- 1.7 A. To reconcile how viral particles can penetrate the hydrogels to infect the encapsulated cells, we propose that microfractures/defects of the hydrogel result in a functional pore size of up to 20 fold greater than predicted by theoretical mesh calculations. These results suggest a new model of hydrogel structure, and have exciting implications for tissue engineering and hepatitis virus studies.
View details for DOI 10.1088/1748-6041/4/1/011001
View details for PubMedID 18981544
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Potential for Hepatitis C Virus Resistance to Nitazoxanide or Tizoxanide
ANTIMICROBIAL AGENTS AND CHEMOTHERAPY
2008; 52 (11): 4069-4071
Abstract
Nitazoxanide and its primary metabolite, tizoxanide, inhibit hepatitis C virus (HCV) replication in HCV replicon systems. To study the potential for resistance, we subjected Huh7 cells harboring HCV replicons to serial passage in 250 muM G418 and increasing concentrations of nitazoxanide or tizoxanide. Passage of the replicon-containing cell lines in either compound resulted in increases in the 50% effective concentrations (EC(50)s) (7- to 13-fold), EC(90)s (14- to 36-fold), and 50% cytotoxic concentrations (2- to 4-fold) of both compounds. Serial passage in either compound did not alter the susceptibility of HCV replicons to ribavirin or 2'-C-methylcytidine. Interestingly, serial passage in nitazoxanide or tizoxanide resulted in increased sensitivity to alpha interferon 2b: EC(50)s and EC(90)s were reduced three- and eightfold, respectively. Replicons isolated from these cell lines had no greater ability to confer tizoxanide resistance, or increased susceptibility to alpha interferon, than replicons isolated from the parental cell line that had not previously been exposed to nitazoxanide or tizoxanide. These findings are indicative of a cell-mediated activity differing from that of other anti-HCV drugs but complementary with interferon and are consistent with the enhanced response rates observed clinically when nitazoxanide is combined with pegylated interferon therapy. Finally, unlike data for other compounds in advanced clinical development for HCV, these data are consistent with resistance in HCV replicon-containing cell lines conferred by changes in the host and not by mutations in the virus.
View details for DOI 10.1128/AAC.00078-08
View details for Web of Science ID 000260305600035
View details for PubMedID 18710916
View details for PubMedCentralID PMC2573111
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NITAZOXANIDE (NTZ) IS AN INDUCER EIF2A AND PKR PHOSPHORYLATION
59th Annual Meeting of the American-Association-for-the-Study-of-Liver-Diseases
WILEY-BLACKWELL. 2008: 1151A–1151A
View details for Web of Science ID 000259757402557
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A SMALL MOLECULE INHIBITS HCV REPLICATION BY DISRUPTING NS4B LOCALIZATION
JOHN WILEY & SONS INC. 2008: 1167A
View details for Web of Science ID 000259757402590
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HEPATITIS C VIRAL GENOTYPE AGE IS A PREDICTOR OF THE CLINICAL RESPONSE TO INTERFERON THERAPY
JOHN WILEY & SONS INC. 2008: 763A
View details for Web of Science ID 000259757401402
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POTENTIAL ROLE FOR NITAZOXANIDE IN COMBINATION WITH STAT-C AGENTS FOR THE INHIBITION OF HCV REPLICATION WITHOUT THE DEVELOPMENT OF RESISTANCE
JOHN WILEY & SONS INC. 2008: 356A
View details for Web of Science ID 000259757400106
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PHARMACOLOGICAL INHIBITORS OF A NEW HEPATITIS C TARGET-RNA BINDING BY NS4B-DISCOVERED BY MICROFLUIDIC AFFINITY ANALYSIS
59th Annual Meeting of the American-Association-for-the-Study-of-Liver-Diseases
WILEY-BLACKWELL. 2008: 356A–356A
View details for Web of Science ID 000259757400105
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BINDING DYNAMICS OF HEPATITIS C VIRUS' NONSTRUCTURAL PROTEINS TO CELL AND MODEL MEMBRANES
59th Annual Meeting of the American-Association-for-the-Study-of-Liver-Diseases
WILEY-BLACKWELL. 2008: 758A–759A
View details for Web of Science ID 000259757401390
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Discovery of a hepatitis C target and its pharmacological inhibitors by microfluidic affinity analysis
NATURE BIOTECHNOLOGY
2008; 26 (9): 1019-1027
Abstract
More effective therapies are urgently needed against hepatitis C virus (HCV), a major cause of viral hepatitis. We used in vitro protein expression and microfluidic affinity analysis to study RNA binding by the HCV transmembrane protein NS4B, which plays an essential role in HCV RNA replication. We show that HCV NS4B binds RNA and that this binding is specific for the 3' terminus of the negative strand of the viral genome with a dissociation constant (Kd) of approximately 3.4 nM. A high-throughput microfluidic screen of a compound library identified 18 compounds that substantially inhibited binding of RNA by NS4B. One of these compounds, clemizole hydrochloride, was found to inhibit HCV RNA replication in cell culture that was mediated by its suppression of NS4B's RNA binding, with little toxicity for the host cell. These results yield new insight into the HCV life cycle and provide a candidate compound for pharmaceutical development.
View details for DOI 10.1038/nbt.1490
View details for PubMedID 18758449
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Isolation and transcriptional profiling of purified hepatic cells derived from human embryonic stem cells
STEM CELLS
2008; 26 (8): 2032-2041
Abstract
The differentiation of human embryonic stem cells (hESCs) into functional hepatocytes provides a powerful in vitro model system for studying the molecular mechanisms governing liver development. Furthermore, a well-characterized renewable supply of hepatocytes differentiated from hESCs could be used for in vitro assays of drug metabolism and toxicology, screening of potential antiviral agents, and cell-based therapies to treat liver disease. In this study, we describe a protocol for the differentiation of hESCs toward hepatic cells with complex cellular morphologies. Putative hepatic cells were identified and isolated using a lentiviral vector, containing the alpha-fetoprotein promoter driving enhanced green fluorescent protein expression (AFP:eGFP). Whole-genome transcriptional profiling was performed on triplicate samples of AFP:eGFP+ and AFP:eGFP- cell populations using the recently released Affymetrix Exon Array ST 1.0 (Santa Clara, CA, http://www.affymetrix.com). Statistical analysis of the transcriptional profiles demonstrated that the AFP:eGFP+ population is highly enriched for genes characteristic of hepatic cells. These data provide a unique insight into the complex process of hepatocyte differentiation, point to signaling pathways that may be manipulated to more efficiently direct the differentiation of hESCs toward mature hepatocytes, and identify molecular markers that may be used for further dissection of hepatic cell differentiation from hESCs. Disclosure of potential conflicts of interest is found at the end of this article.
View details for DOI 10.1634/stemcells.2007-0964
View details for PubMedID 18535157
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A drug-controllable tag for visualizing newly synthesized proteins in cells and whole animals
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
2008; 105 (22): 7744-7749
Abstract
Research on basic cellular processes involving local production or delivery of proteins, such as activity-dependent synaptic modification in neurons, would benefit greatly from a robust, nontoxic method to visualize selectively newly synthesized copies of proteins of interest within cells, tissues, or animals. We report a technique for covalent labeling of newly synthesized proteins of interest based on drug-dependent preservation of epitope tags. Epitope tags are removed from proteins of interest immediately after translation by the activity of a sequence-specific protease until the time a protease inhibitor is added, after which newly synthesized protein copies retain their tags. This method, which we call TimeSTAMP for time-specific tagging for the age measurement of proteins, allows sensitive and nonperturbative visualization and quantification of newly synthesized proteins of interest with exceptionally tight temporal control. We demonstrate applications of TimeSTAMP in retrospectively identifying growing synapses in cultured neurons and in visualizing the distribution of recently synthesized proteins in intact fly brains.
View details for DOI 10.1073/pnas.0803060105
View details for Web of Science ID 000256648600023
View details for PubMedID 18511556
View details for PubMedCentralID PMC2402386
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Isolation of human fetal liver progenitors and their enhanced proliferation by three-dimensional coculture with endothelial cells
TISSUE ENGINEERING PART A
2008; 14 (6): 995-1006
Abstract
Liver progenitor cells, characterized by the coexpression of biliary and hepatocyte lineage markers and the ability to form colonies in culture, were isolated by flow cytometry from primary human fetal livers. These prospectively isolated liver progenitor cells supported hepatitis D virus infection, expressed, and produced albumin and alpha-fetoprotein, as tracked by albumin- and alpha-fetoprotein-driven lentiviral promoter reporter constructs and measured by ELISA, respectively. Coculture in three-dimensional (3D) fibrin gel with endothelial cells resulted in the formation of vascular structures by the endothelial cells and increased proliferation of liver progenitors. The enhanced proliferation of liver progenitors that was observed when liver progenitors and endothelial cells were cultured in direct contact was not achieved when liver progenitors and endothelial cells were cultured on adjacent but separate matrices and when they were cultured across transwell membranes. In conclusion, coculture of liver progenitors and endothelial cells in three-dimensional matrix resulted in enhanced liver progenitor proliferation and function. This coculture methodology offers a novel coculture system that could be applied for the development of engineered liver tissues.
View details for DOI 10.1089/ten.tea.2007.0087
View details for PubMedID 19230124
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The nucleotide binding motif of hepatitis C virus NS4B can mediate cellular transformation and tumor formation without ha-ras co-transfection
HEPATOLOGY
2008; 47 (3): 827-835
Abstract
Hepatitis C virus (HCV) is an important cause of chronic liver disease and is complicated by hepatocellular carcinoma (HCC). Mechanisms whereby the virus promotes cellular transformation are poorly understood. We hypothesized that the guanosine triphosphatase activity encoded in the HCV NS4B protein's nucleotide binding motif (NBM) might play a role in the transformation process. Here we report that NS4B can transform NIH-3T3 cells, leading to tumor formation in vivo. This transformation was independent of co-transfection with activated Ha-ras. Detailed analyses of NS4B mutants revealed that this transforming activity could be progressively inhibited and completely abrogated by increasing genetic impairment of the NS4B nucleotide binding motif.NS4B has in vitro and in vivo tumorigenic potential, and the NS4B transforming activity is indeed mediated by its NBM. Moreover, our results suggest that pharmacological inhibition of the latter might inhibit not only HCV replication but also the associated HCC.
View details for DOI 10.1002/hep.22108
View details for PubMedID 18081150
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Studies of the potential for resistance to nitazoxanide or tizoxanide
43rd Annual Meeting of the European-Association-for-the-Study-of-the-Liver
ELSEVIER SCIENCE BV. 2008: S11–S11
View details for Web of Science ID 000256683200023
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TBC1D20 is a Rab1 GTPase-activating protein that mediates hepatitis C virus replication
JOURNAL OF BIOLOGICAL CHEMISTRY
2007; 282 (50): 36354-36361
Abstract
Like other viruses, productive hepatitis C virus (HCV) infection depends on certain critical host factors. We have recently shown that an interaction between HCV nonstructural protein NS5A and a host protein, TBC1D20, is necessary for efficient HCV replication. TBC1D20 contains a TBC (Tre-2, Bub2, and Cdc16) domain present in most known Rab GTPase-activating proteins (GAPs). The latter are master regulators of vesicular membrane transport, as they control the activity of membrane-associated Rab proteins. To better understand the role of the NS5A-TBC1D20 interaction in the HCV life cycle, we used a biochemical screen to identify the TBC1D20 Rab substrate. TBC1D20 was found to be the first known GAP for Rab1, which is implicated in the regulation of anterograde traffic between the endoplasmic reticulum and the Golgi complex. Mutation of amino acids implicated in Rab GTPase activation by other TBC domain-containing GAPs abrogated the ability of TBC1D20 to activate Rab1 GTPase. Overexpression of TBC1D20 blocked the transport of exogenous vesicular stomatitis virus G protein from the endoplasmic reticulum, validating the involvement of TBC1D20 in this pathway. Rab1 depletion significantly decreased HCV RNA levels, suggesting a role for Rab1 in HCV replication. These results highlight a novel mechanism by which viruses can hijack host cell machinery and suggest an attractive model whereby the NS5A-TBC1D20 interaction may promote viral membrane-associated RNA replication.
View details for DOI 10.1074/jbc.M705221200
View details for PubMedID 17901050
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Hepatitis d.
Current treatment options in gastroenterology
2007; 10 (6): 456-463
Abstract
The hepatitis delta virus (HDV) is a defective RNA virus that requires the help of hepatitis B virus (HBV) for virion assembly and penetration into hepatocytes. Thus, it can only cause disease in individuals who carry HBV. HDV infection is present worldwide, predominantly in tropical and subtropical areas. However, with increased HBV control, HDV infection has significantly declined, although stably persisting, in developed countries. Most HDV-infected individuals develop chronic hepatitis D, and in approximately 80% of those cases, chronic hepatitis D progresses to cirrhosis within 5 to 10 years. The only approved therapy for chronic hepatitis D is interferon-alpha. Although transplantation offers a safe therapeutic option for managing end-stage HDV disease, novel therapeutic approaches are urgently needed.
View details for PubMedID 18221606
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Creation of lipid partitions by deposition of amphipathic viral peptides
LANGMUIR
2007; 23 (21): 10855-10863
Abstract
Phospholipid vesicles exhibit a natural characteristic to fuse and reform into a continuous single bilayer membrane on hydrophilic solid substrates such as glass, mica, and silica. The resulting solid-supported bilayer mimics physiological tendencies such as lipid flip-flop and lateral mobility. The lateral mobility of fluorescently labeled lipids fused into solid-supported bilayers is found to change upon deposition on the membrane surface of an amphipathic alpha-helical peptide (AH) derived from the hepatitis C virus (HCV) NS5A protein. The binding of the AH peptide to a phospholipid bilayer, with the helical axis parallel to the bilayer, leads to immobilization of the bilayer. We used AFM to better understand the mechanistic details of this specific interaction, and determined that the diminished fluidity of the bilayer is due to membrane thinning. Utilizing this specific interaction between AH peptides and lipid molecules, we demonstrate a novel process for the creation of lipid partition by employing AH peptides as agents to immobilize lipid molecules, thus creating a patterned solid support with partition-defined areas of freely mobile lipid bilayers. This architecture could have a wide range of applications in novel sensing, biotechnology, high-throughput screening, and biomimetic strategies.
View details for DOI 10.1021/1000640h
View details for PubMedID 17803321
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A Rab-GAP TBC domain protein binds hepatitis C virus NS5A and mediates viral replication
JOURNAL OF VIROLOGY
2007; 81 (20): 11096-11105
Abstract
Hepatitis C virus (HCV) is an important cause of liver disease worldwide. Current therapies are inadequate for most patients. Using a two-hybrid screen, we isolated a novel cellular binding partner interacting with the N terminus of HCV nonstructural protein NS5A. This partner contains a TBC Rab-GAP (GTPase-activating protein) homology domain found in all known Rab-activating proteins. As the first described interaction between such a Rab-GAP and a viral protein, this finding suggests a new mechanism whereby viruses may subvert host cell machinery for mediating the endocytosis, trafficking, and sorting of their own proteins. Moreover, depleting the expression of this partner severely impairs HCV RNA replication with no obvious effect on cell viability. These results suggest that pharmacologic disruption of this NS5A-interacting partner can be contemplated as a potential new antiviral strategy against a pathogen affecting nearly 3% of the world's population.
View details for DOI 10.1128/JVI.01249-07
View details for PubMedID 17686842
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Interim data from a randomized controlled trial of nitazoxanide-peginterferon-ribavirin, nitazoxanide-peginterferon and peginterferon-ribavirin in the treatment of patients with chronic hepatitis C genotype 4
JOHN WILEY & SONS INC. 2007: 316A–317A
View details for Web of Science ID 000249910400184
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Employing two different quartz crystal microbalance models to study changes in viscoelastic behavior upon transformation of lipid vesicles to a bilayer on a gold surface
ANALYTICAL CHEMISTRY
2007; 79 (18): 7027-7035
Abstract
By analyzing the viscoelastic properties of two distinct layers, a layer of "soft" vesicles and a "rigid" bilayer, we have created a model system to permit the study of film behavior in the region of nonlinear mass and frequency change (non-Sauerbrey). The structural transformation of lipid vesicles to a bilayer is shown to be accompanied by significant changes in their physical properties. After the adsorption and saturation of intact vesicles on gold surfaces, the adsorbed vesicle layer exhibits a soft, water-rich, viscoelastic state. The AH peptide, a vesicle-destabilizing agent, is then added to trigger the formation of a much thinner (approximately 5 nm), compact, and rigid bilayer. In this study, we used the quartz crystal microbalance with dissipation technique. Large non-Sauerbrey frequency and energy dissipation changes characterize the viscoelastic nature of adsorbed intact vesicle films thicker than approximately 10 nm. Once the transformation is complete, the frequency changes along with zero energy dissipation for sufficiently thin films (t approximately 5 nm) were effectively modeled with the Sauerbrey equation. Furthermore, we checked the validity of the Voigt-Voinova model in which the quartz substrate is treated as a Voigt element, which is beyond the Sauerbrey description. The calculations treating the film as having a constant viscosity agreed well with the Voigt-Voinova model. These results were compared to calculations done using the electromechanical (EM) model, which does not require a series expansion. The Voigt-Voinova results were in excellent agreement with the EM model, providing evidence that the expansion used in their study is quite accurate.
View details for PubMedID 17685547
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Employing an amphipathic viral peptide to create a lipid bilayer on Au and TiO2
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
2007; 129 (33): 10050-?
View details for DOI 10.1021/ja0701412
View details for PubMedID 17661464
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Binding dynamics of hepatitis C virus' NS5A amphipathic peptide to cell and model membranes
JOURNAL OF VIROLOGY
2007; 81 (12): 6682-6689
Abstract
Membrane association of the hepatitis C virus NS5A protein is required for viral replication. This association is dependent on an N-terminal amphipathic helix (AH) within NS5A and is restricted to a subset of host cell intracellular membranes. The mechanism underlying this specificity is not known, but it may suggest a novel strategy for developing specific antiviral therapy. Here we have probed the mechanistic details of NS5A AH-mediated binding to both cell-derived and model membranes by use of biochemical membrane flotation and quartz crystal microbalance (QCM) with dissipation. With both assays, we observed AH-mediated binding to model lipid bilayers. When cell-derived membranes were coated on the quartz nanosensor, however, significantly more binding was detected, and the QCM-derived kinetic measurements suggested the existence of an interacting receptor in the target membranes. Biochemical flotation assays performed with trypsin-treated cell-derived membranes exhibited reduced AH-mediated membrane binding, while membrane binding of control cytochrome b5 remained unaffected. Similarly, trypsin treatment of the nanosensor coated with cellular membranes abolished AH peptide binding to the cellular membranes but did not affect the binding of a control lipid-binding peptide. These results therefore suggest that a protein plays a critical role in mediating and stabilizing the binding of NS5A's AH to its target membrane. These results also demonstrate the successful development of a new nanosensor technology ideal both for studying the interaction between a protein and its target membrane and for developing inhibitors of that interaction.
View details for DOI 10.1128/JVI.02783-06
View details for PubMedID 17428867
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The power of silence: Application of small interfering RNAs to gastrointestinal diseases
GASTROENTEROLOGY
2007; 132 (7): 2291-2295
View details for DOI 10.1053/j.gastro.2007.04.056
View details for PubMedID 17570202
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A putative Rab GTPase-activating protein binds hepatitis C virus NS5A and mediates viral replication
JOHN WILEY & SONS INC. 2006: 692A
View details for Web of Science ID 000241362302441
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Molecular virology of the hepatitis C virus: Implication for novel therapies
INFECTIOUS DISEASE CLINICS OF NORTH AMERICA
2006; 20 (1): 81-?
Abstract
With the advent of second-generation agents that for the first time specifically target individual HCV proteins, HCV-specific therapy has arrived. The study of HCV molecular virology has helped make this possible and is helping us to identify additional new antiviral targets that will be targeted by third-generation drugs. Key to these efforts is the development of high-efficiency HCV replicons. The future effective pharmacologic control of HCV will likely consist of a cocktail of simultaneously administered virus-specific agents with independent targets. This should minimize the emergence of resistance against any single agent. The way we treat HCV should change dramatically over the next few years.
View details for DOI 10.1016/j.idc.2006.01.001
View details for PubMedID 16527650
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Prenylation of HDAg and antiviral drug development
HEPATITIS DELTA VIRUS
2006; 307: 133-149
Abstract
Hepatitis delta virus (HDV) is an important cause of acute and chronic liver disease. Current medical therapies are unable to effectively eradicate HDV infections. Research into the molecular virology of the HDV life cycle has revealed a fascinating collection of biology. These insights are now beginning to be translated into new potential treatment strategies. For example, an essential step in the virus assembly process involves the post-translational lipid modification of a specific HDV protein, namely prenylation of large delta antigen. Preventing prenylation abolishes virus particle formation. Drugs capable of specifically inhibiting prenylation have been developed for use in humans. These agents represent a new class of antiviral agents, with HDV as a first target. Here, a brief review of the HDV life cycle emphasizing the role of prenylation is presented along with implications for drug development and therapy.
View details for Web of Science ID 000238999800007
View details for PubMedID 16903224
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Novel therapies for hepatitis C virus based on lessons from virology.
Clinical gastroenterology and hepatology
2005; 3 (10): S86-8
Abstract
As we improve our understanding of the molecular virology of hepatitis C virus (HCV), a variety of new potential antiviral strategies are emerging. Moving beyond interferon and ribavirin, these new strategies for the first time are aimed at HCV-specific targets. It is expected, by analogy with other infections, that effective pharmacologic control of HCV will be achieved best by using a cocktail of such virus-specific agents, each designed against an independent target. As a result, the way we treat HCV should change dramatically over the next few years.
View details for PubMedID 16234068
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Molecular virology of the hepatitis C virus: implication for novel therapies.
Clinics in liver disease
2005; 9 (3): 353-?
Abstract
The study of hepatitis C virus (HCV) molecular virology is helping to shape the future of our anti-HCV strategies by identifying new antiviral targets. With the advent of agents that specifically target individual HCV proteins, HCV-specific therapy has arrived. Key to these efforts is the development of high-efficiency HCV replicons. The future effective pharmacologic control of HCV will likely consist of a cocktail of simultaneously administered virus-specific agents with independent targets. This should minimize the emergence of resistance against any single agent. The way we treat HCV should change dramatically over the next few years.
View details for PubMedID 16023970
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Confronting New and Old Antiviral Threats: Broad Spectrum Potential of Prenylation Inhibitors
ANTIVIRAL DRUG DISCOVERY FOR EMERGING DISEASES AND BIOTERRORISM THREATS
2005: 249–61
View details for DOI 10.1002/0471716715.ch11
View details for Web of Science ID 000298179900012
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Hepatitis C virus core protein associates with detergent-resistant membranes distinct from classical plasma membrane rafts
JOURNAL OF VIROLOGY
2004; 78 (21): 12047-12053
Abstract
A subpopulation of hepatitis C virus (HCV) core protein in cells harboring full-length HCV replicons is biochemically associated with detergent-resistant membranes (DRMs) in a manner similar to that of markers of classical lipid rafts. Core protein does not, however, colocalize in immunofluorescence studies with classical plasma membrane raft markers, such as caveolin-1 and the B subunit of cholera toxin, suggesting that core protein is bound to cytoplasmic raft microdomains distinct from caveolin-based rafts. Furthermore, while both the structural core protein and the nonstructural protein NS5A associate with membranes, they do not colocalize in the DRMs. Finally, the ability of core protein to localize to the DRMs did not require other elements of the HCV polyprotein. These results may have broad implications for the HCV life cycle and suggest that the HCV core may be a valuable probe for host cell biology.
View details for DOI 10.1128/JVI.78.21.12047-12053.2004
View details for PubMedID 15479844
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A nucleotide binding motif in hepatitis C virus (HCV) NS4B mediates HCV RNA replication
JOURNAL OF VIROLOGY
2004; 78 (20): 11288-11295
Abstract
Hepatitis C virus (HCV) is a major cause of viral hepatitis. There is no effective therapy for most patients. We have identified a nucleotide binding motif (NBM) in one of the virus's nonstructural proteins, NS4B. This structural motif binds and hydrolyzes GTP and is conserved across HCV isolates. Genetically disrupting the NBM impairs GTP binding and hydrolysis and dramatically inhibits HCV RNA replication. These results have exciting implications for the HCV life cycle and novel antiviral strategies.
View details for PubMedID 15452248
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An n-terminal amphipathic helix in hepatitis C virus (HCV) NS4B mediates membrane association, correct localization of replication complex proteins, and HCV RNA replication
JOURNAL OF VIROLOGY
2004; 78 (20): 11393-11400
Abstract
Like other positive-strand RNA viruses, hepatitis C virus (HCV) is believed to replicate its RNA in association with host cell cytoplasmic membranes. Because of its association with such membranes, NS4B, one of the virus's nonstructural proteins, may play an important role in this process, although the mechanistic details are not well understood. We identified a putative N-terminal amphipathic helix (AH) in NS4B that mediates membrane association. Introduction of site-directed mutations designed to disrupt the hydrophobic face of the AH abolishes the AH's ability to mediate membrane association. An AH in NS4B is conserved across HCV isolates. Completely disrupting the amphipathic nature of NS4B's N-terminal helix abolished HCV RNA replication, whereas partial disruption resulted in an intermediate level of replication. Finally, immunofluorescence studies revealed that HCV replication complex components were mislocalized in the AH-disrupted mutant. These results identify a key membrane-targeting domain which can form the basis for developing novel antiviral strategies.
View details for DOI 10.1128/JVI.78.20.11393-11400.2004
View details for PubMedID 15452261
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Overdependence on the host-an Achilles' heel of HCV?
Hepatology
2004; 39 (6): 1734-1735
View details for PubMedID 15185316
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Testing antivirals against hepatitis delta virus: farnesyl transferase inhibitors.
Methods in molecular medicine
2004; 96: 539-553
View details for PubMedID 14762290
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Prenylation inhibitors: a novel class of antiviral agents
JOURNAL OF ANTIMICROBIAL CHEMOTHERAPY
2003; 52 (6): 883-886
Abstract
Prenylation is a site-specific lipid modification of proteins. Although first described for a variety of cellular proteins, it has become apparent that viruses can also make use of this post-translational modification provided by their host cells. Depriving a virus access to prenylation can have dramatic effects on the targeted virus's life cycle. Selective pharmacological inhibitors of prenylating enzymes have been developed and shown to have potent antiviral effects in both in vitro and in vivo systems. Because prenylation inhibitors target a host cell function, are available in oral form and are surprisingly well tolerated in human trials, these compounds represent an attractive new class of antiviral agents with potential for broad-spectrum activity. After a brief outline of host cell prenylation pathways, we review below the development of prenylation inhibition as an antiviral strategy applied to a prototype target, hepatitis delta virus (HDV), and discuss the potential application of prenylation inhibitors to a broad range of other viruses.
View details for DOI 10.1093/jac/dkg490
View details for PubMedID 14613953
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In vivo antiviral efficacy of prenylation inhibitors against hepatitis delta virus
JOURNAL OF CLINICAL INVESTIGATION
2003; 112 (3): 407-414
Abstract
Hepatitis delta virus (HDV) can dramatically worsen liver disease in patients coinfected with hepatitis B virus (HBV). No effective medical therapy exists for HDV. The HDV envelope requires HBV surface antigen proteins provided by HBV. Once inside a cell, however, HDV can replicate its genome in the absence of any HBV gene products. In vitro, HDV virion assembly is critically dependent on prenyl lipid modification, or prenylation, of its nucleocapsid-like protein large delta antigen. To overcome limitations of current animal models and to test the hypothesis that pharmacologic prenylation inhibition can prevent the production of HDV virions in vivo, we established a convenient mouse-based model of HDV infection capable of yielding viremia. Such mice were then treated with the prenylation inhibitors FTI-277 and FTI-2153. Both agents were highly effective at clearing HDV viremia. As expected, HDV inhibition exhibited duration-of-treatment dependence. These results provide the first preclinical data supporting the in vivo efficacy of prenylation inhibition as a novel antiviral therapy with potential application to HDV and a wide variety of other viruses.
View details for DOI 10.1172/JCI200317704
View details for PubMedID 12897208
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Amphipathic helix-dependent localization of NS5A mediates hepatitis C virus RNA replication
JOURNAL OF VIROLOGY
2003; 77 (10): 6055-6061
Abstract
We identified an N-terminal amphipathic helix (AH) in one of hepatitis C virus (HCV)'s nonstructural proteins, NS5A. This AH is necessary and sufficient for membrane localization and is conserved across isolates. Genetically disrupting the AH impairs HCV replication. Moreover, an AH peptide-mimic inhibits the membrane association of NS5A in a dose-dependent manner. These results have exciting implications for the HCV life cycle and novel antiviral strategies.
View details for DOI 10.1128/JVI.77.10.6055-6061.2003
View details for PubMedID 12719597
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A prenylation inhibitor prevents production of infectious hepatitis delta virus particles
JOURNAL OF VIROLOGY
2002; 76 (20): 10465-10472
Abstract
Hepatitis delta virus (HDV) causes both acute and chronic liver disease throughout the world. Effective medical therapy is lacking. Previous work has shown that the assembly of HDV virus-like particles (VLPs) could be abolished by BZA-5B, a compound with farnesyltransferase inhibitory activity. Here we show that FTI-277, another farnesyltransferase inhibitor, prevented the production of complete, infectious HDV virions of two different genotypes. Thus, in spite of the added complexity and assembly determinants of infectious HDV virions compared to VLPs, the former are also sensitive to pharmacological prenylation inhibition. Moreover, production of HDV genotype III virions, which is associated with particularly severe clinical disease, was as sensitive to prenylation inhibition as was that of HDV genotype I virions. Farnesyltransferase inhibitors thus represent an attractive potential class of novel antiviral agents for use against HDV, including the genotypes associated with most severe disease.
View details for DOI 10.1128/JVI.76.20.10465-10472.2002
View details for PubMedID 12239323
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Membrane association of HCVNS5A: A novel antiviral target.
W B SAUNDERS CO. 2001: 440A
View details for Web of Science ID 000171224701065
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Host-microbe interactions: viruses - Lessons in defense: hepatitic C, a case study - Editorial overview
CURRENT OPINION IN MICROBIOLOGY
2000; 3 (4): 363-365
View details for Web of Science ID 000088817300007
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Sustained survival of human hepatocytes in mice: A model for in vivo infection with human hepatitis B and hepatitis delta viruses
NATURE MEDICINE
2000; 6 (3): 327-331
Abstract
Persistence of hepatocytes transplanted into the same or related species has been established. The long-term engraftment of human hepatocytes into rodents would be useful for the study of human viral hepatitis, where it might allow the species, technical and size limitations of the current animal models to be overcome. Although transgenic mice expressing the hepatitis B virus (HBV) genome produce infectious virus in their serum, the viral life cycle is not complete, in that the early stages of viral binding and entry into hepatocytes and production of an episomal transcriptional DNA template do not occur. As for hepatitis delta virus (HDV), another cause of liver disease, no effective therapy exists to eradicate infection, and it remains resistant even to recent regimens that have considerably changed the treatment of HBV (ref. 13). Here, we demonstrate long-term engraftment of primary human hepatocytes transplanted in a matrix under the kidney capsule of mice with administration of an agonistic antibody against c-Met. These mice were susceptible to HBV infection and completion of the viral life cycle. In addition, we demonstrate super-infection of the HBV-infected mice with HDV. Our results describe a new xenotransplant model that allows study of multiple aspects of human hepatitis viral infections, and may enhance studies of human liver diseases.
View details for PubMedID 10700236
- Shutting the door on hepatitis delta virus (HDV): Sensitivity to prenylation inhibition prompts new therapeutic strategy Viral Hepatitis Reviews 1999; 53: 13-26
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Use of a prenylation inhibitor as a novel antiviral agent
JOURNAL OF VIROLOGY
1998; 72 (11): 9303-9306
Abstract
No specific therapy exists for hepatitis delta virus (HDV), which can cause severe liver disease. Molecular genetic studies have implicated the prenylation site of large delta antigen as a critical determinant of HDV particle assembly. We have established a cell culture model which produces HDV-like particles, and we show that delta antigen prenylation can be pharmacologically inhibited by the prenylation inhibitor BZA-5B. Furthermore, BZA-5B specifically abolishes particle production in a dose-dependent manner. These results demonstrate that the use of such a prenylation inhibitor-based antiviral therapy may be feasible and identify a novel class of potential antiviral agents.
View details for PubMedID 9765479
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Finding the iron in the melting pot - Practical use of a new genetic assay for hereditary hemochromatosis
WESTERN JOURNAL OF MEDICINE
1998; 168 (6): 525-527
View details for Web of Science ID 000074374100010
View details for PubMedID 9655998
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DELIVERY OF LIPOSOME-ENCAPSULATED RNA TO CELLS EXPRESSING INFLUENZA-VIRUS HEMAGGLUTININ
METHODS IN ENZYMOLOGY
1993; 221: 327-339
View details for Web of Science ID A1993LU44300027
View details for PubMedID 7689688
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IDENTIFICATION OF A PRENYLATION SITE IN DELTA-VIRUS LARGE ANTIGEN
SCIENCE
1992; 256 (5061): 1331-1333
Abstract
During replication, hepatitis delta virus (HDV) switches from production of small to large delta antigen. Both antigen isoforms have an HDV genome binding domain and are packaged into hepatitis B virus (HBV)-derived envelopes but differ at their carboxy termini. The large antigen was shown to contain a terminal CXXX box and undergo prenylation. The large, but not the small, antigen formed secreted particles when expressed singly with HBV surface antigen. Mutation of Cys211 in the CXXX box of the large antigen abolished both prenylation and particle formation, suggesting that this site is important for virion morphogenesis.
View details for Web of Science ID A1992HW13500037
View details for PubMedID 1598578
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TRANSDOMINANT INHIBITION OF HUMAN HEPATITIS-DELTA VIRUS GENOME REPLICATION
JOURNAL OF VIROLOGY
1991; 65 (5): 2357-2361
Abstract
Infection with hepatitis delta virus (HDV) is an important cause of acute and chronic liver disease and can be rapidly fatal. Sequencing of the HDV RNA genome has revealed variability at the C-terminal end of the delta antigen reading frame. One genome type (termed the S genome) synthesizes a 24-kDa protein thought to be required for genome replication. Another genome type (termed the L genome) extends the reading frame by 19 amino acids as a result of a single base change. Replication of the S and L genomes was studied in cultured fibroblasts. While the S genome efficiently initiated genome replication, the L genome did not. Moreover, in a codelivery experiment, L genome RNA inhibited replication of the S genome. Potent trans inhibition was also observed following cotransfection of the S genome and a plasmid encoding the larger delta antigen. Mutational analysis indicated that the inhibitory activity was not a simple function of the large delta antigen reading frame's extra length. Implications for the viral life cycle, clinical infection, and potential treatment are discussed.
View details for Web of Science ID A1991FG77700026
View details for PubMedID 2016764
View details for PubMedCentralID PMC240587
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REPLICATION OF MONOMERIC GENOMIC-DELTA RNA IN CULTURED-CELLS
3RD INTERNATIONAL SYMP ON HEPATITIS DELTA VIRUS
WILEY-LISS, INC. 1991: 293–297
View details for Web of Science ID A1991BT15R00034
View details for PubMedID 2020705
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DELIVERY OF MACROMOLECULES INTO CELLS EXPRESSING A VIRAL MEMBRANE-FUSION PROTEIN
METHODS IN CELL BIOLOGY
1989; 31: 155-176
View details for Web of Science ID A1989AV40500009
View details for PubMedID 2779447