Faculty Opinions recommendation of B Cell Receptor Activation and Chemical Induction Trigger Caspase-Mediated Cleavage of PIAS1 to Facilitate Epstein-Barr Virus Reactivation.

AbstractAntigen recognition by the B cell receptor (BCR) is a physiological trigger for reactivation of Epstein-Barr virus (EBV) and can be recapitulated in vitro by cross-linking of surface immunoglobulins. Previously, we identified a subset of EBV microRNAs (miRNAs) that attenuate BCR signal transduction and subsequently, dampen lytic replication in B cells. The roles of host miRNAs in virus reactivation are not completely understood. To investigate this process, we profiled the small RNAs in latently infected and reactivated Burkitt’s lymphoma cells, and identified several miRNAs, such as miR-141, that are induced upon BCR cross-linking. Notably, EBV encodes a viral miRNA, miR-BART9, with sequence homology to miR-141. To better understand the functions of these two miRNAs, we examined their molecular targets and experimentally validated multiple candidates commonly regulated by both miRNAs. Targets included transcriptional regulators of the EBV immediate early promoters and B cell transcription factors, leading us to hypothesize that these miRNAs modulate kinetics of the latent to lytic switch in B cells. Through functional assays, we identified roles for miR-141 and EBV miR-BART9 and one specific target, FOXO3, in lytic reactivation. Our data support a model whereby EBV exploits BCR-responsive miR-141 and further mimics activity of this miRNA family via a viral miRNA to promote productive virus replication.ImportanceEBV is a human pathogen associated with several malignancies. A key aspect of lifelong virus persistence is the ability to switch between latent and lytic replication modes. Mechanisms governing latency and lytic reactivation are only partly understood, and how the EBV latent to lytic switch is post-transcriptionally regulated remains an outstanding question. This study sheds light on how miR-141 expression is regulated in Burkitt’s lymphoma cells, and identifies a role for FOXO3, a common target of both miR-141 and viral miR-BART9, in modulating EBV reactivation.

Download Full-text

Syphilis Reactivates Latent Epstein-Barr Virus Reservoir via Toll-Like Receptor 2 and B-Cell Receptor Activation

Open Forum Infectious Diseases ◽

10.1093/ofid/ofz317 ◽

2019 ◽

Vol 6 (9) ◽

Cited By ~ 1

Author(s):

Julia R Hirsiger ◽

Philipp S Fuchs ◽

Peter Häusermann ◽

Bojana Müller-Durovic ◽

Thomas Daikeler ◽

...

Keyword(s):

B Cell ◽

Epstein Barr Virus ◽

Cell Receptor ◽

Receptor Activation ◽

B Cell Receptor ◽

Toll Like Receptor ◽

Barr Virus ◽

Ebv Reactivation ◽

Epstein Barr

Abstract Latent Epstein-Barr virus (EBV) infection can clinically reactivate in immunosuppressed individuals causing lymphoproliferative disease and rarely hepatitis. In this study, we provide in vivo and in vitro evidence that Treponema pallidum infection can cause EBV reactivation with hepatitis in an immunocompetent patient. We report the diagnostic challenges and immunological findings of coinciding syphilis and EBV-associated hepatitis. Using an in vitro EBV-reactivation assay, we demonstrate that T pallidum reactivates latent EBV in a Toll-like receptor (TLR)2/B-cell receptor signaling-dependent manner. Epstein-Barr virus-associated reactivation or lymphoproliferation should be considered in infections with pathogens that activate TLR2.

Download Full-text

Rewiring of B cell receptor signaling by Epstein–Barr virus LMP2A

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2007946117 ◽

2020 ◽

Vol 117 (42) ◽

pp. 26318-26327

Author(s):

Kamonwan Fish ◽

Federico Comoglio ◽

Arthur L. Shaffer ◽

Yanlong Ji ◽

Kuan-Ting Pan ◽

...

Keyword(s):

Cell Cycle ◽

B Cells ◽

B Cell ◽

Epstein Barr Virus ◽

Cell Receptor ◽

B Cell Receptor ◽

Barr Virus ◽

Human B Cells ◽

Bcr Signaling ◽

Epstein Barr

Epstein–Barr virus (EBV) infects human B cells and reprograms them to allow virus replication and persistence. One key viral factor in this process is latent membrane protein 2A (LMP2A), which has been described as a B cell receptor (BCR) mimic promoting malignant transformation. However, how LMP2A signaling contributes to tumorigenesis remains elusive. By comparing LMP2A and BCR signaling in primary human B cells using phosphoproteomics and transcriptome profiling, we identified molecular mechanisms through which LMP2A affects B cell biology. Consistent with the literature, we found that LMP2A mimics a subset of BCR signaling events, including tyrosine phosphorylation of the kinase SYK, the calcium initiation complex consisting of BLNK, BTK, and PLCγ2, and its downstream transcription factor NFAT. However, the majority of LMP2A-induced signaling events markedly differed from those induced by BCR stimulation. These included differential phosphorylation of kinases, phosphatases, adaptor proteins, transcription factors such as nuclear factor κB (NF-κB) and TCF3, as well as widespread changes in the transcriptional output of LMP2A-expressing B cells. LMP2A affected apoptosis and cell-cycle checkpoints by dysregulating the expression of apoptosis regulators such as BCl-xL and the tumor suppressor retinoblastoma-associated protein 1 (RB1). LMP2A cooperated with MYC and mutant cyclin D3, two oncogenic drivers of Burkitt lymphoma, to promote proliferation and survival of primary human B cells by counteracting MYC-induced apoptosis and by inhibiting RB1 function, thereby promoting cell-cycle progression. Our results indicate that LMP2A is not a pure BCR mimic but rather rewires intracellular signaling in EBV-infected B cells that optimizes cell survival and proliferation, setting the stage for oncogenic transformation.

Download Full-text

Signatures of B-cell receptor diversity in B lymphocytes following Epstein-Barr virus transformation

Physiological Genomics ◽

10.1152/physiolgenomics.00124.2018 ◽

2019 ◽

Vol 51 (6) ◽

pp. 197-207

Author(s):

Meimei Lai ◽

Qiongdan Wang ◽

Yutian Lu ◽

Xi Xu ◽

Ying Xia ◽

...

Keyword(s):

B Cell ◽

Cell Line ◽

Epstein Barr Virus ◽

High Throughput Sequencing ◽

Cell Receptor ◽

B Cell Receptor ◽

Human Virus ◽

Barr Virus ◽

Ebv Infection ◽

Epstein Barr

Epstein-Barr virus (EBV) is a widespread human virus that establishes latent infection, potentially leading to tumors, hematological disorders, and other severe diseases. EBV infections are associated with diverse symptoms and affect various organs; therefore, early diagnosis and treatment are crucial. B cell receptor (BCR) repertoires of B cell surface immunoglobulins have been widely studied for their association with various infectious diseases. However, the specific genetic changes that modulate the BCR repertoires after an EBV infection are still poorly understood. In this study, we employed high-throughput sequencing (HTS) to investigate the diversity of BCR repertoires in an EBV-transformed lymphoblastic cell line (LCL). Compared with the noninfected control B cell line, the LCL exhibited a decrease in overall BCR diversity but displayed an increase in the expansion of some dominant rearrangements such as IGHV4-31/IGHJ4, IGHV4-59/IGHJ4, IGHV5-51/IGHJ3, and IGHV3-74/IGHJ3. A higher frequency of occurrence of these rearrangement types was confirmed in patients with EBV infection. Interestingly, the IGHV3-74 rearrangement was only detected in EBV-infected children, suggesting that our experimental observations were not coincidental. In addition, we identified a highly dominant consensus motif, CAR(xRx)YGSG(xYx)FD, in complementarity-determining region 3 (CDR3) sequences of the heavy chain in the LCL. Our findings demonstrated the utility of HTS technology for studying the variations in signature motifs of the BCR repertoires after EBV infection. We propose that the analysis of BCR repertoire sequences represents a promising method for diagnosing early EBV infections and developing novel antibody- and vaccine-based therapies against such infections.

Download Full-text

Calcium-dependent signalling in B-cell lymphomas

Oncogene ◽

10.1038/s41388-021-02025-8 ◽

2021 ◽

Author(s):

Fedor Berditchevski ◽

Eanna Fennell ◽

Paul G. Murray

Keyword(s):

B Cells ◽

B Cell ◽

Cell Receptor ◽

Receptor Activation ◽

B Cell Receptor ◽

Signalling Pathways ◽

B Cell Lymphomas ◽

Calcium Dependent ◽

Barr Virus ◽

Epstein Barr

AbstractInduced waves of calcium fluxes initiate multiple signalling pathways that play an important role in the differentiation and maturation of B-cells. Finely tuned transient Ca+2 fluxes from the endoplasmic reticulum in response to B-cell receptor (BCR) or chemokine receptor activation are followed by more sustained calcium influxes from the extracellular environment and contribute to the mechanisms responsible for the proliferation of B-cells, their migration within lymphoid organs and their differentiation. Dysregulation of these well-balanced mechanisms in B-cell lymphomas results in uncontrolled cell proliferation and resistance to apoptosis. Consequently, several cytotoxic drugs (and anti-proliferative compounds) used in standard chemotherapy regimens for the treatment of people with lymphoma target calcium-dependent pathways. Furthermore, ~10% of lymphoma associated mutations are found in genes with functions in calcium-dependent signalling, including those affecting B-cell receptor signalling pathways. In this review, we provide an overview of the Ca2+-dependent signalling network and outline the contribution of its key components to B cell lymphomagenesis. We also consider how the oncogenic Epstein-Barr virus, which is causally linked to the pathogenesis of a number of B-cell lymphomas, can modify Ca2+-dependent signalling.

Download Full-text