- Specificity of Immunoglobulin High-Throughput Sequencing Minimal Residual Disease Monitoring in Non-Hodgkin Lymphomas. Blood advances 2023
Distinct Hodgkin lymphoma subtypes defined by noninvasive genomic profiling.
The scarcity of malignant Hodgkin and Reed-Sternberg (HRS) cells hamper tissue-based comprehensive genomic profiling of classic Hodgkin lymphoma (cHL). Liquid biopsies, in contrast, show promise for molecular profiling of cHL due to relatively high circulating tumor DNA (ctDNA) levels1-4. Here, we show that the plasma representation of mutations exceeds the bulk tumor representation in most cases, making cHL particularly amenable to noninvasive profiling. Leveraging single-cell transcriptional profiles of cHL tumors, we demonstrate HRS ctDNA shedding to be shaped by DNASE1L3, whose increased tumor microenvironment-derived expression drives high ctDNA concentrations. Using this insight, we comprehensively profile 366 patients, revealing two distinct cHL genomic subtypes with characteristic clinical and prognostic correlates, as well as distinct transcriptional and immunological profiles. Furthermore, we identify a novel class of truncating IL4R-mutations that are dependent on IL13 signaling and therapeutically targetable with IL4R blocking antibodies. Finally, using PhasED-Seq5 we demonstrate the clinical value of pre- and on-treatment ctDNA levels for longitudinally refining cHL risk prediction, and for detection of radiographically occult minimal residual disease. Collectively, these results support the utility of noninvasive strategies for genotyping and dynamic monitoring of cHL as well as capturing molecularly distinct subtypes with diagnostic, prognostic, and therapeutic potential.
View details for DOI 10.1038/s41586-023-06903-x
View details for PubMedID 38081297
Spheromers reveal robust T cell responses to the Pfizer/BioNTech vaccine and attenuated peripheral CD8+ T cell responses post SARS-CoV-2 infection.
T cells are a critical component of the response to SARS-CoV-2, but their kinetics after infection and vaccination are insufficiently understood. Using "spheromer" peptide-MHC multimer reagents, we analyzed healthy subjects receiving two doses of the Pfizer/BioNTech BNT162b2 vaccine. Vaccination resulted in robust spike-specific T cell responses for the dominant CD4+ (HLA-DRB1∗15:01/S191) and CD8+ (HLA-A∗02/S691) T cell epitopes. Antigen-specific CD4+ and CD8+ T cell responses were asynchronous, with the peak CD4+ T cell responses occurring 1 week post the second vaccination (boost), whereas CD8+ T cells peaked 2 weeks later. These peripheral T cell responses were elevated compared with COVID-19 patients. We also found that previous SARS-CoV-2 infection resulted in decreased CD8+ T cell activation and expansion, suggesting that previous infection can influence the T cell response to vaccination.
View details for DOI 10.1016/j.immuni.2023.03.005
View details for PubMedID 36996809
View details for PubMedCentralID PMC10017386
- Specificity & Precision of Minimal Residual Disease Monitoring in DLBCL Using Ig-HTS AMER SOC HEMATOLOGY. 2022: 6403-6404
- Distinct Molecular Subtypes of Classic Hodgkin Lymphoma Identified By Comprehensive Noninvasive Profiling AMER SOC HEMATOLOGY. 2022: 1295-1296
- Viral cfDNA Profiling Reveals Distinct EBV Subtypes and Stratifies Risk in Hodgkin Lymphomas AMER SOC HEMATOLOGY. 2022: 1318-1319
- Maria-I: A Deep-Learning Approach for Accurate Prediction of MHC Class I Tumor Neoantigen Presentation AMER SOC HEMATOLOGY. 2019
Tyr1 phosphorylation promotes phosphorylation of Ser2 on the C-terminal domain of eukaryotic RNA polymerase II by P-TEFb
The Positive Transcription Elongation Factor b (P-TEFb) phosphorylates Ser2 residues of the C-terminal domain (CTD) of the largest subunit (RPB1) of RNA polymerase II and is essential for the transition from transcription initiation to elongation in vivo. Surprisingly, P-TEFb exhibits Ser5 phosphorylation activity in vitro. The mechanism garnering Ser2 specificity to P-TEFb remains elusive and hinders understanding of the transition from transcription initiation to elongation. Through in vitro reconstruction of CTD phosphorylation, mass spectrometry analysis, and chromatin immunoprecipitation sequencing (ChIP-seq) analysis, we uncover a mechanism by which Tyr1 phosphorylation directs the kinase activity of P-TEFb and alters its specificity from Ser5 to Ser2. The loss of Tyr1 phosphorylation causes an accumulation of RNA polymerase II in the promoter region as detected by ChIP-seq. We demonstrate the ability of Tyr1 phosphorylation to generate a heterogeneous CTD modification landscape that expands the CTD's coding potential. These findings provide direct experimental evidence for a combinatorial CTD phosphorylation code wherein previously installed modifications direct the identity and abundance of subsequent coding events by influencing the behavior of downstream enzymes.
View details for DOI 10.7554/eLife.48725
View details for Web of Science ID 000483988000001
View details for PubMedID 31385803
View details for PubMedCentralID PMC6715403
Snapshots of C-S Cleavage in Egt2 Reveals Substrate Specificity and Reaction Mechanism
CELL CHEMICAL BIOLOGY
2018; 25 (5): 519-+
Sulfur incorporation in the biosynthesis of ergothioneine, a histidine thiol derivative, differs from other well-characterized transsulfurations. A combination of a mononuclear non-heme iron enzyme-catalyzed oxidative C-S bond formation and a subsequent pyridoxal 5'-phosphate (PLP)-mediated C-S lyase reaction leads to the net transfer of a sulfur atom from a cysteine to a histidine. In this study, we structurally and mechanistically characterized a PLP-dependent C-S lyase Egt2, which mediates the sulfoxide C-S bond cleavage in ergothioneine biosynthesis. A cation-π interaction between substrate and enzyme accounts for Egt2's preference of sulfoxide over thioether as a substrate. Using mutagenesis and structural biology, we captured three distinct states of the Egt2 C-S lyase reaction cycle, including a labile sulfenic intermediate captured in Egt2 crystals. Chemical trapping and high-resolution mass spectrometry were used to confirm the involvement of the sulfenic acid intermediate in Egt2 catalysis.
View details for DOI 10.1016/j.chembiol.2018.02.002
View details for Web of Science ID 000432448700005
View details for PubMedID 29503207
View details for PubMedCentralID PMC5959753