All Publications


  • Computational drug repositioning of atorvastatin for ulcerative colitis. Journal of the American Medical Informatics Association : JAMIA Bai, L., Scott, M. K., Steinberg, E., Kalesinskas, L., Habtezion, A., Shah, N. H., Khatri, P. 2021

    Abstract

    OBJECTIVE: Ulcerative colitis (UC) is a chronic inflammatory disorder with limited effective therapeutic options for long-term treatment and disease maintenance. We hypothesized that a multi-cohort analysis of independent cohorts representing real-world heterogeneity of UC would identify a robust transcriptomic signature to improve identification of FDA-approved drugs that can be repurposed to treat patients with UC.MATERIALS AND METHODS: We performed a multi-cohort analysis of 272 colon biopsy transcriptome samples across 11 publicly available datasets to identify a robust UC disease gene signature. We compared the gene signature to in vitro transcriptomic profiles induced by 781 FDA-approved drugs to identify potential drug targets. We used a retrospective cohort study design modeled after a target trial to evaluate the protective effect of predicted drugs on colectomy risk in patients with UC from the Stanford Research Repository (STARR) database and Optum Clinformatics DataMart.RESULTS: Atorvastatin treatment had the highest inverse-correlation with the UC gene signature among non-oncolytic FDA-approved therapies. In both STARR (n = 827) and Optum (n = 7821), atorvastatin intake was significantly associated with a decreased risk of colectomy, a marker of treatment-refractory disease, compared to patients prescribed a comparator drug (STARR: HR = 0.47, P = .03; Optum: HR = 0.66, P = .03), irrespective of age and length of atorvastatin treatment.DISCUSSION & CONCLUSION: These findings suggest that atorvastatin may serve as a novel therapeutic option for ameliorating disease in patients with UC. Importantly, we provide a systematic framework for integrating publicly available heterogeneous molecular data with clinical data at a large scale to repurpose existing FDA-approved drugs for a wide range of human diseases.

    View details for DOI 10.1093/jamia/ocab165

    View details for PubMedID 34529084

  • Novel circulating and tissue monocytes as well as macrophages in pancreatitis and recovery. Gastroenterology Manohar, M., Jones, E. K., Rubin, S. J., Subrahmanyam, P. B., Swaminathan, G., Mikhail, D., Bai, L., Singh, G., Wei, Y., Sharma, V., Siebert, J. C., Maecker, H. T., Husain, S. Z., Park, W. G., Pandol, S. J., Habtezion, A. 2021

    Abstract

    BACKGROUND AND AIMS: Acute pancreatitis (AP) is an inflammatory disease with mild to severe course that is associated with local and systemic complications and significant mortality. Uncovering inflammatory pathways that lead to progression and recovery will inform ways to monitor and/or develop effective therapies.METHODS: We performed single-cell mass cytometry (CyTOF) analysis to identify pancreatic and systemic inflammatory signals during mild (referred as AP), severe AP (SAP) and recovery using two independent experimental models and blood from AP and recurrent AP (RAP) patients. Flowcytometric validation of monocytes subsets identified by CyTOF analysis was performed independently.RESULTS: Ly6C+ inflammatory monocytes were most altered cells in the pancreas during experimental AP, recovery, and SAP. Deep profiling uncovered heterogeneity among pancreatic and blood monocytes and identified seven novel subsets during AP and recovery, and six monocyte subsets during SAP. Notably, a dynamic shift in pancreatic CD206+ macrophage population was observed during AP and recovery. Deeper profiling of the CD206+ macrophage identified seven novel subsets during AP, recovery and SAP. DE analysis of these novel monocyte and CD206+ macrophage subsets revealed significantly altered surface (CD44, CD54, CD115, CD140a, CD196, PDPN) and functional markers (IFN-gamma, IL-4, IL-22, LAP-TGF-beta, TNF-alpha, T-bet, RoRgammat) that were associated with recovery and SAP. Moreover, a targeted functional analysis further revealed distinct expression of pro- and anti-inflammatory cytokines by pancreatic CD206+ macrophage subsets as the disease either progressed or resolved. Similarly, we identified heterogeneity among circulating classical inflammatory monocytes (CD14+CD16-) and novel subsets in patients with AP and RAP.CONCLUSION: We identified several novel monocyte/macrophage subsets with unique phenotype and functional characteristics that are associated with AP, recovery, and SAP. Our findings highlight differential innate immune responses during AP progression and recovery that can be leveraged for future disease monitoring and targeting.

    View details for DOI 10.1053/j.gastro.2021.08.033

    View details for PubMedID 34450180

  • Vitamin D is Associated with α4β7+ Immunophenotypes and Predicts Vedolizumab Therapy Failure in Patients with Inflammatory Bowel Disease. Journal of Crohn's & colitis Gubatan, J., Rubin, S. J., Bai, L., Haileselassie, Y., Levitte, S., Balabanis, T., Patel, A., Sharma, A., Sinha, S. R., Habtezion, A. 2021

    Abstract

    Vitamin D downregulates the in vitro expression of the gut-tropic integrin α4β7 on immune cells. The clinical relevance of this finding in patients with inflammatory bowel disease (IBD) is unclear. We tested the hypothesis that vitamin D is associated with α4β7 immunophenotypes and risk of vedolizumab (anti- α4β7) failure in IBD.We performed single-cell immunophenotyping of peripheral and intestinal immune cells using mass cytometry (CyTOF) in vedolizumab-naïve patients with IBD (N=48). We analyzed whole-genome mucosal gene expression (GSE73661) from GEMINI I and GEMINI long-term safety (LTS) to determine the association between vitamin D receptor (VDR) and integrin alpha-4 (ITGA4) and beta-7 (ITGB7) genes. We estimated the odds of vedolizumab failure with low pre-treatment vitamin D in a combined retrospective and prospective IBD cohort (N= 252) with logistic regression.Immunophenotyping revealed that higher 25(OH)D was associated with decreased α4β7+ peripheral blood mononuclear cells (R = -0.400, P < 0.01) and α4β7+ intestinal leukocytes (R = -0.538, P= 0.03). Serum 25(OH)D was inversely associated with α4β7+ peripheral B cells and natural killer (NK) cells and α4β7+ intestinal B cells, NK cells, monocytes, and macrophages. Mucosal expression of VDR was inversely associated with ITGA4 and ITGB7 expression. In multivariate analysis, 25(OH)D < 25 ng/mL was associated with increased vedolizumab primary non-response during induction (OR 26.10, 95% CI 14.30-48.90, P<0.001) and failure at 1-year follow-up (OR 6.10, 95% CI 3.06-12.17, P<0.001).Low serum 25(OH)D is associated with α4β7+ immunophenotypes and predicts future vedolizumab failure in patients with IBD.

    View details for DOI 10.1093/ecco-jcc/jjab114

    View details for PubMedID 34180967

  • Effects of processing conditions on stability of immune analytes in human blood. Scientific reports Gottfried-Blackmore, A., Rubin, S. J., Bai, L., Aluko, S., Yang, Y., Park, W., Habtezion, A. 2020; 10 (1): 17328

    Abstract

    Minimizing variability in collection and processing of human blood samples for research remains a challenge. Delaying plasma or serum isolation after phlebotomy (processing delay) can cause perturbations of numerous analytes. Thus, a comprehensive understanding of how processing delay affects major endpoints used in human immunology research is necessary. Therefore, we studied how processing delay affects commonly measured cytokines and immune cell populations. We hypothesized that short-term time delays inherent to human research in serum and plasma processing impact commonly studied immunological analytes. Blood from healthy donors was subjected to processing delays commonly encountered in sample collection, and then assayed by 62-plex Luminex panel, 40-parameter mass cytometry panel, and 540,000 transcript expression microarray. Variance for immunological analytes was estimated using each individual's baseline as a control. In general, short-term processing delay led to small changes in plasma and serum cytokines (range-10.8 to 43.5%), markers and frequencies of peripheral blood mononuclear cell phenotypes (range 0.19 to 3.54 fold), and whole blood gene expression (stable for>20K genes)-with several exceptions described herein. Importantly, we built an open-access web application allowing investigators to estimate the degree of variance expected from processing delay for measurements of interest based on the data reported here.

    View details for DOI 10.1038/s41598-020-74274-8

    View details for PubMedID 33060628

  • Mass cytometry reveals systemic and local immune signatures that distinguish inflammatory bowel diseases. Nature communications Rubin, S. J., Bai, L., Haileselassie, Y., Garay, G., Yun, C., Becker, L., Streett, S. E., Sinha, S. R., Habtezion, A. 2019; 10 (1): 2686

    Abstract

    Inflammatory bowel disease (IBD) includes Crohn's disease and ulcerative colitis. Each disease is characterized by a diverse set of potential manifestations, which determine patients' disease phenotype. Current understanding of phenotype determinants is limited, despite increasing prevalence and healthcare costs. Diagnosis and monitoring of disease requires invasive procedures, such as endoscopy and tissue biopsy. Here we report signatures of heterogeneity between disease diagnoses and phenotypes. Using mass cytometry, we analyze leukocyte subsets, characterize their function(s), and examine gut-homing molecule expression in blood and intestinal tissue from healthy and/or IBD subjects. Some signatures persist in IBD despite remission, and many signatures are highly represented by leukocytes that express gut trafficking molecules. Moreover, distinct systemic and local immune signatures suggest patterns of cell localization in disease. Our findings highlight the importance of gut tropic leukocytes in circulation and reveal that blood-based immune signatures differentiate clinically relevant subsets of IBD.

    View details for DOI 10.1038/s41467-019-10387-7

    View details for PubMedID 31217423

  • The Distinct and Cooperative Roles of Toll-Like Receptor 9 and Receptor for Advanced Glycation End Products in Modulating In Vivo Inflammatory Responses to Select CpG and Non-CpG Oligonucleotides. Nucleic acid therapeutics Paz, S. n., Hsiao, J. n., Cauntay, P. n., Soriano, A. n., Bai, L. n., Machemer, T. n., Xiao, X. n., Guo, S. n., Hung, G. n., Younis, H. n., Bennett, C. F., Henry, S. n., Yun, T. J., Burel, S. n. 2017; 27 (5): 272–84

    Abstract

    Antisense oligonucleotides (ASOs) are widely accepted therapeutic agents that suppress RNA transcription. While the majority of ASOs are well tolerated in vivo, few sequences trigger inflammatory responses in absence of conventional CpG motifs. In this study, we identified non-CpG oligodeoxy-nucleotide (ODN) capable of triggering an inflammatory response resulting in B cell and macrophage activation in a MyD88- and TLR9-dependent manner. In addition, we found the receptor for advance glycation end product (RAGE) receptor to be involved in the initiation of inflammatory response to suboptimal concentrations of both CpG- and non-CpG-containing ODNs. In contrast, dosing RAGE KO mice with high doses of CpG or non-CpG ODNs lead to a stronger inflammatory response than observed in wild-type mice. Together, our data provide a previously uncharacterized in vivo mechanism contingent on ODN-administered dose, where TLR9 governs the primary response and RAGE plays a distinct and cooperative function in providing a pivotal role in balancing the immune response.

    View details for DOI 10.1089/nat.2017.0668

    View details for PubMedID 28605247

  • CRISPR Immunological Memory Requires a Host Factor for Specificity. Molecular cell Nuñez, J. K., Bai, L. n., Harrington, L. B., Hinder, T. L., Doudna, J. A. 2016; 62 (6): 824–33

    Abstract

    Bacteria and archaea employ adaptive immunity against foreign genetic elements using CRISPR-Cas systems. To generate immunological memory, the Cas1-Cas2 protein complex captures 30-40 base pair segments of foreign DNA and catalyzes their integration into the host genome as unique spacer sequences. Although spacers are inserted strictly at the A-T-rich leader end of CRISPR loci in vivo, the molecular mechanism of leader-specific spacer integration remains poorly understood. Here we show that the E. coli integration host factor (IHF) protein is required for spacer acquisition in vivo and for integration into linear DNA in vitro. IHF binds to the leader sequence and induces a sharp DNA bend, allowing the Cas1-Cas2 integrase to catalyze the first integration reaction at the leader-repeat border. Together, these results reveal that Cas1-Cas2-mediated spacer integration requires IHF-induced target DNA bending and explain the elusive role of CRISPR leader sequences during spacer acquisition.

    View details for DOI 10.1016/j.molcel.2016.04.027

    View details for PubMedID 27211867