1
|
Robinson WH, Younis S, Love ZZ, Steinman L, Lanz TV. Epstein-Barr virus as a potentiator of autoimmune diseases. Nat Rev Rheumatol 2024:10.1038/s41584-024-01167-9. [PMID: 39390260 DOI: 10.1038/s41584-024-01167-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/02/2024] [Indexed: 10/12/2024]
Abstract
The Epstein-Barr virus (EBV) is epidemiologically associated with development of autoimmune diseases, including systemic lupus erythematosus, Sjögren syndrome, rheumatoid arthritis and multiple sclerosis. Although there is well-established evidence for this association, the underlying mechanistic basis remains incompletely defined. In this Review, we discuss the role of EBV infection as a potentiator of autoimmune rheumatic diseases. We review the EBV life cycle, viral transcription programmes, serological profiles and lytic reactivation. We discuss the epidemiological and mechanistic associations of EBV with systemic lupus erythematosus, Sjögren syndrome, rheumatoid arthritis and multiple sclerosis. We describe the potential mechanisms by which EBV might promote autoimmunity, including EBV nuclear antigen 1-mediated molecular mimicry of human autoantigens; EBV-mediated B cell reprogramming, including EBV nuclear antigen 2-mediated dysregulation of autoimmune susceptibility genes; EBV and host genetic factors, including the potential for autoimmunity-promoting strains of EBV; EBV immune evasion and insufficient host responses to control infection; lytic reactivation; and other mechanisms. Finally, we discuss the therapeutic implications and potential therapeutic approaches to targeting EBV for the treatment of autoimmune disease.
Collapse
Affiliation(s)
- William H Robinson
- Division of Immunology and Rheumatology, Stanford University School of Medicine, Stanford, CA, USA.
- VA Palo Alto Health Care System, Palo Alto, CA, USA.
| | - Shady Younis
- Division of Immunology and Rheumatology, Stanford University School of Medicine, Stanford, CA, USA
- VA Palo Alto Health Care System, Palo Alto, CA, USA
| | - Zelda Z Love
- Division of Immunology and Rheumatology, Stanford University School of Medicine, Stanford, CA, USA
- VA Palo Alto Health Care System, Palo Alto, CA, USA
| | - Lawrence Steinman
- Department of Neurology and Neurological Sciences and Paediatrics, Stanford University School of Medicine, Stanford, CA, USA
| | - Tobias V Lanz
- Division of Immunology and Rheumatology, Stanford University School of Medicine, Stanford, CA, USA
- Institute for Immunity Transplantation and Infection, Stanford University School of Medicine, Stanford, CA, USA
| |
Collapse
|
2
|
Zhao Y, Zhang Q, Zhang B, Dai Y, Gao Y, Li C, Yu Y, Li C. Epstein-Barr Viruses: Their Immune Evasion Strategies and Implications for Autoimmune Diseases. Int J Mol Sci 2024; 25:8160. [PMID: 39125729 PMCID: PMC11311853 DOI: 10.3390/ijms25158160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2024] [Revised: 07/23/2024] [Accepted: 07/24/2024] [Indexed: 08/12/2024] Open
Abstract
Epstein-Barr virus (EBV), a member of the γ-herpesvirus family, is one of the most prevalent and persistent human viruses, infecting up to 90% of the adult population globally. EBV's life cycle includes primary infection, latency, and lytic reactivation, with the virus primarily infecting B cells and epithelial cells. This virus has evolved sophisticated strategies to evade both innate and adaptive immune responses, thereby maintaining a lifelong presence within the host. This persistence is facilitated by the expression of latent genes such as EBV nuclear antigens (EBNAs) and latent membrane proteins (LMPs), which play crucial roles in viral latency and oncogenesis. In addition to their well-known roles in several types of cancer, including nasopharyngeal carcinoma and B-cell lymphomas, recent studies have identified the pathogenic roles of EBV in autoimmune diseases such as multiple sclerosis, rheumatoid arthritis, and systemic lupus erythematosus. This review highlights the intricate interactions between EBV and the host immune system, underscoring the need for further research to develop effective therapeutic and preventive strategies against EBV-associated diseases.
Collapse
Affiliation(s)
- Yuehong Zhao
- School of Medicine, The Chinese University of Hong Kong, Shenzhen 518172, China; (Y.Z.); (Q.Z.); (B.Z.); (Y.D.); (Y.G.); (C.L.)
| | - Qi Zhang
- School of Medicine, The Chinese University of Hong Kong, Shenzhen 518172, China; (Y.Z.); (Q.Z.); (B.Z.); (Y.D.); (Y.G.); (C.L.)
| | - Botian Zhang
- School of Medicine, The Chinese University of Hong Kong, Shenzhen 518172, China; (Y.Z.); (Q.Z.); (B.Z.); (Y.D.); (Y.G.); (C.L.)
| | - Yihao Dai
- School of Medicine, The Chinese University of Hong Kong, Shenzhen 518172, China; (Y.Z.); (Q.Z.); (B.Z.); (Y.D.); (Y.G.); (C.L.)
| | - Yifei Gao
- School of Medicine, The Chinese University of Hong Kong, Shenzhen 518172, China; (Y.Z.); (Q.Z.); (B.Z.); (Y.D.); (Y.G.); (C.L.)
| | - Chenzhong Li
- School of Medicine, The Chinese University of Hong Kong, Shenzhen 518172, China; (Y.Z.); (Q.Z.); (B.Z.); (Y.D.); (Y.G.); (C.L.)
| | - Yijing Yu
- School of Medicine, The Chinese University of Hong Kong, Shenzhen 518172, China; (Y.Z.); (Q.Z.); (B.Z.); (Y.D.); (Y.G.); (C.L.)
| | - Conglei Li
- School of Medicine, The Chinese University of Hong Kong, Shenzhen 518172, China; (Y.Z.); (Q.Z.); (B.Z.); (Y.D.); (Y.G.); (C.L.)
- Ciechanover Institute of Precision and Regenerative Medicine, School of Medicine, The Chinese University of Hong Kong, Shenzhen 518172, China
| |
Collapse
|
3
|
Yang L, Pu J, Cai F, Zhang Y, Gao R, Zhuang S, Liang Y, Wu Z, Pan S, Song J, Han F, Tang J, Wang X. Chronic Epstein-Barr virus infection: A potential junction between primary Sjögren's syndrome and lymphoma. Cytokine 2023; 168:156227. [PMID: 37244248 DOI: 10.1016/j.cyto.2023.156227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 04/24/2023] [Accepted: 05/04/2023] [Indexed: 05/29/2023]
Abstract
Primary Sjögren's syndrome (pSS) is an autoimmune disease that targets exocrine glands, leading to exocrine dysfunction. Due to its propensity to infect epithelial and B cells, Epstein-Barr virus (EBV) is hypothesized to be related with pSS. Through molecular mimicry, the synthesis of specific antigens, and the release of inflammatory cytokines, EBV contributes to the development of pSS. Lymphoma is the most lethal outcome of EBV infection and the development of pSS. As a population-wide virus, EBV has had a significant role in the development of lymphoma in people with pSS. In the review, we will discuss the possible causes of the disease.
Collapse
Affiliation(s)
- Lufei Yang
- Department of Rheumatology and Immunology, Tongji Hospital, School of Medicine, Tongji University, Shanghai 200065, China
| | - Jincheng Pu
- Department of Rheumatology and Immunology, Tongji Hospital, School of Medicine, Tongji University, Shanghai 200065, China
| | - Feiyang Cai
- Department of Experimental Medicine, Faculty of Medicine, McGill University, Montréal, Québec, Canada; Gerald Bronfman Department of Oncology, Segal Cancer Centre, Lady Davis Institute and Jewish General Hospital, McGill University, Montreal, Quebec, Canada
| | - Youwei Zhang
- Department of Rheumatology and Immunology, Tongji Hospital, School of Medicine, Tongji University, Shanghai 200065, China
| | - Ronglin Gao
- Department of Rheumatology and Immunology, Tongji Hospital, School of Medicine, Tongji University, Shanghai 200065, China
| | - Shuqi Zhuang
- Department of Rheumatology and Immunology, Tongji Hospital, School of Medicine, Tongji University, Shanghai 200065, China
| | - Yuanyuan Liang
- Department of Rheumatology and Immunology, Tongji Hospital, School of Medicine, Tongji University, Shanghai 200065, China
| | - Zhenzhen Wu
- Department of Rheumatology and Immunology, Tongji Hospital, School of Medicine, Tongji University, Shanghai 200065, China
| | - Shengnan Pan
- Department of Rheumatology and Immunology, Tongji Hospital, School of Medicine, Tongji University, Shanghai 200065, China
| | - Jiamin Song
- Department of Rheumatology and Immunology, Tongji Hospital, School of Medicine, Tongji University, Shanghai 200065, China
| | - Fang Han
- Department of Rheumatology and Immunology, Tongji Hospital, School of Medicine, Tongji University, Shanghai 200065, China
| | - Jianping Tang
- Department of Rheumatology and Immunology, Tongji Hospital, School of Medicine, Tongji University, Shanghai 200065, China.
| | - Xuan Wang
- Department of Rheumatology and Immunology, Tongji Hospital, School of Medicine, Tongji University, Shanghai 200065, China.
| |
Collapse
|
4
|
Madayag K, Incrocci R, Swanson‐Mungerson M. The impact of Epstein-Barr virus latent membrane protein 2A on the production of B cell activating factor of the tumor necrosis factor family (BAFF), APRIL and their receptors. Immun Inflamm Dis 2022; 10:e729. [PMID: 36301035 PMCID: PMC9597489 DOI: 10.1002/iid3.729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 10/05/2022] [Accepted: 10/13/2022] [Indexed: 11/06/2022] Open
Abstract
INTRODUCTION Epstein-Barr virus (EBV) establishes a lifelong infection in human B cells where the virus consistently expresses Latent Membrane Protein 2A (LMP2A) to promote B cell survival. A prior study indicates that LMP2A may increase the production of the pro-survival factor, B cell Activating Factor of the tumor necrosis factor family (BAFF), which could also indirectly increase B cell survival. The current study sought to extend these findings and determine if LMP2A increased BAFF production and/or the responsiveness of LMP2A-expressing cells to this cytokine. METHODS Four independently derived LMP2A-negative and -positive B cell lymphoma cell lines were analyzed for BAFF and APRIL levels by both ELISA and Western Blot analysis. Additionally, flow cytometric analysis measured any LMP2A-dependent changes in the receptors for BAFF and APRIL (BAFF-R, transmembrane activator and calcium-modulator and cyclophilin ligand interactor [TACI], B cell maturation antigen [BCMA]) in both LMP2A-negative and -positive B cell lymphoma cell lines. RESULTS In contrast to previous reports, our data indicate that LMP2A does not increase the expression of BAFF or APRIL by Western blot analysis or ELISA. Additionally, flow cytometric analysis indicates that LMP2A does not influence the expression of the receptors for BAFF and APRIL: TACI, BAFF-R, and BCMA. CONCLUSION Therefore, these data suggest that while EBV utilizes other latency proteins to regulate BAFF production, EBV does not appear to use LMP2A to enhance BAFF-or APRIL-dependent survival to promote EBV latency.
Collapse
Affiliation(s)
- Kevin Madayag
- Department of Biomedical SciencesCollege of Graduate StudiesDowners GroveIllinoisUSA
| | - Ryan Incrocci
- Department of Microbiology and Immunology, College of Graduate StudiesMidwestern UniversityDowners GroveIllinoisUSA
| | - Michelle Swanson‐Mungerson
- Department of Microbiology and Immunology, College of Graduate StudiesMidwestern UniversityDowners GroveIllinoisUSA
| |
Collapse
|
5
|
Reguraman N, Hassani A, Philip P, Khan G. Uncovering early events in primary Epstein-Barr virus infection using a rabbit model. Sci Rep 2021; 11:21220. [PMID: 34707156 PMCID: PMC8551192 DOI: 10.1038/s41598-021-00668-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 10/11/2021] [Indexed: 12/13/2022] Open
Abstract
Epstein-Barr virus (EBV) is an oncogenic herpesvirus implicated in the pathogenesis of several malignant and non-malignant conditions. However, a number of fundamental aspects about the biology of EBV and the mechanism(s) by which this virus induces pathology remain unknown. One major obstacle has been the lack of a suitable animal model for EBV infection. In this study, using our recently established rabbit model of EBV infection, we examined the early events following primary EBV infection. We show that, both immunocompetent and immunosuppressed animals were readily susceptible to EBV infection. However, immunosuppressed animals showed marked splenomegaly and widespread infection. Following EBV infection, the virus primarily targeted naïve IgM+, CD20+, CD21+ and CD79a+ B cells. Infected cells expressed varying sets of viral latent/lytic gene products. Notably, co-expression of latent and lytic proteins in the same cell was not observed. Infected cells in type 0/1 latency (EBERs+), were small and proliferating (Ki67+). By contrast, cells in type 2/3 latency (LMP1+), were large, non-proliferating (Ki-67-) and p53+. Although infected B-cells were widely present in splenic follicles, they did not express germinal center marker, BCL-6. Taken together, this study shows for the first time, some of the early events following primary EBV infection.
Collapse
Affiliation(s)
- Narendran Reguraman
- Department of Microbiology and Immunology, College of Medicine and Health Sciences, Tawam Hospital Campus, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Asma Hassani
- Department of Microbiology and Immunology, College of Medicine and Health Sciences, Tawam Hospital Campus, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Pretty Philip
- Department of Microbiology and Immunology, College of Medicine and Health Sciences, Tawam Hospital Campus, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Gulfaraz Khan
- Department of Microbiology and Immunology, College of Medicine and Health Sciences, Tawam Hospital Campus, United Arab Emirates University, Al Ain, United Arab Emirates.
| |
Collapse
|
6
|
Epstein-Barr Virus-Encoded Latent Membrane Protein 2A Downregulates GCNT3 via the TGF-β1/Smad-mTORC1 Signaling Axis. J Virol 2021; 95:JVI.02481-20. [PMID: 33658337 PMCID: PMC8139646 DOI: 10.1128/jvi.02481-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Increasing evidence shows that Epstein-Barr virus (EBV) infection is closely related to various lymphoid and epithelioid malignancies. However, the underlying mechanisms are unclear. GCNT3 (core 2β-1,6-acetylglucosaminyltransferase) is a new type of core mucin synthase, and its expression in EBV-associated gastric cancer (EBVaGC) is lower than that in EBV-negative gastric cancer (EBVnGC). EBV-encoded latent membrane protein 2A (LMP2A) is a transmembrane protein with tumorigenic transformation properties. Here, we demonstrated that LMP2A inhibited the transcription of GCNT3 by inhibiting Smad2/3 and Smad4. LMP2A restrained the activation of the mTORC1 pathway by inactivating the TGF-β1/Smad pathway and then downregulated GCNT3 expression. The mTORC1-GCNT3 pathway promoted cell proliferation and migration and inhibited G0/G1 cell arrest. Related proteins involved in epithelial-mesenchymal transition (EMT) were downstream molecules of the TGF-β1/Smad-mTORC1-GCNT3 pathway. GCNT3 inhibited autophagy by inducing mTORC1 phosphorylation. These findings indicate that targeting the TGF-β1/Smad-mTORC1-GCNT3 axis may represent a novel therapeutic target in GC.ImportanceEpstein-Barr virus (EBV) is an opportunistic pathogen, and the latent membrane protein 2A (LMP2A) encoded by EBV plays a key role in ensuring the incubation period of EBV. Glycosylation modification is an important marker of cancer cells, and recent studies have reported that it is related to EBV. Our conclusions provide deeper theoretical support for the role of LMP2A and TGF/Smad-mTORC1-GCNT3 in EBVaGC and help to understand glycosylation abnormalities in cancer. Our results may provide novel therapeutic targets for the treatment of gastric cancer against the TGF/Smad-mTORC1-GCNT3 signaling cascade.
Collapse
|
7
|
Abstract
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.
Collapse
|
8
|
Kearns PKA, Casey HA, Leach JP. Hypothesis: Multiple sclerosis is caused by three-hits, strictly in order, in genetically susceptible persons. Mult Scler Relat Disord 2018; 24:157-174. [PMID: 30015080 DOI: 10.1016/j.msard.2018.06.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 05/25/2018] [Accepted: 06/18/2018] [Indexed: 12/15/2022]
Abstract
Multiple Sclerosis is a chronic, progressive and debilitating neurological disease which, despite extensive study for over 100 years, remains of enigmatic aetiology. Drawn from the epidemiological evidence, there exists a consensus that there are environmental (possibly infectious) factors that contribute to disease pathogenesis that have not yet been fully elucidated. Here we propose a three-tiered hypothesis: 1) a clinic-epidemiological model of multiple sclerosis as a rare late complication of two sequential infections (with the temporal sequence of infections being important); 2) a proposal that the first event is helminthic infection with Enterobius Vermicularis, and the second is Epstein Barr Virus infection; and 3) a proposal for a testable biological mechanism, involving T-Cell exhaustion for Epstein-Barr Virus protein LMP2A. We believe that this model satisfies some of the as-yet unexplained features of multiple sclerosis epidemiology, is consistent with the clinical and neuropathological features of the disease and is potentially testable by experiment. This model may be generalizable to other autoimmune diseases.
Collapse
|
9
|
Kraal LJN, Nijland ML, Germar KL, Baeten DLP, ten Berge IJM, Fehres CM. Anti-citrullinated protein antibody response after primary EBV infection in kidney transplant patients. PLoS One 2018; 13:e0197219. [PMID: 29746558 PMCID: PMC5945038 DOI: 10.1371/journal.pone.0197219] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 04/27/2018] [Indexed: 12/15/2022] Open
Abstract
Rheumatoid arthritis (RA) is a chronic inflammatory disease of synovial joints, characterized by the presence of the highly disease-specific anti-citrullinated protein antibodies (ACPA) in approximately 70% of patients. Epstein-Barr virus (EBV) has previously been suggested to be involved in the pathophysiology of RA. However, given the high incidence of EBV in the general population and the difficulty of detecting initial infection, providing a direct link between EBV infection and RA development has remained elusive. We hypothesized that primary EBV infection may be a trigger for the development of the ACPA response in vivo. Using a unique cohort of 26 kidney transplant patients with a primary EBV infection, the presence of ACPA before and following infection was determined. No increase in IgG anti-CCP2 titers was detected following EBV infection. IgG anti-CCP2 antibodies were present in two patients and borderline positive in another. These three patients were HLA-DR4 negative. To test whether EBV infection may trigger a non-class switched anti-CCP2 response, IgM anti-CCP2 antibodies were analyzed. No general trend in the IgM anti-CCP2 response was observed following EBV infection. Since two out of the three IgG anti-CCP2 (borderline) positive patients were diagnosed with IgA nephropathy, 23 additional IgA nephropathy patients were tested for IgG anti-CCP2, regardless of their EBV status. All of these patients were IgG anti-CCP2 negative, indicating that IgG anti-CCP2 is not commonly present in IgA nephropathy patients. Collectively, these data do not support the hypothesis that EBV does trigger the highly RA specific ACPA response.
Collapse
Affiliation(s)
- Lianne J. N. Kraal
- Department of Clinical Immunology and Rheumatology, Amsterdam Rheumatology and immunology Center, Academic Medical Center/ University of Amsterdam, Amsterdam, The Netherlands
| | - Marieke L. Nijland
- Renal Transplant Unit, Department of Nephrology, Department of Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Kristine L. Germar
- Department of Clinical Immunology and Rheumatology, Amsterdam Rheumatology and immunology Center, Academic Medical Center/ University of Amsterdam, Amsterdam, The Netherlands
| | - Dominique L. P. Baeten
- Department of Clinical Immunology and Rheumatology, Amsterdam Rheumatology and immunology Center, Academic Medical Center/ University of Amsterdam, Amsterdam, The Netherlands
| | - Ineke J. M. ten Berge
- Renal Transplant Unit, Department of Nephrology, Department of Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Cynthia M. Fehres
- Department of Clinical Immunology and Rheumatology, Amsterdam Rheumatology and immunology Center, Academic Medical Center/ University of Amsterdam, Amsterdam, The Netherlands
- * E-mail:
| |
Collapse
|
10
|
Abstract
It is more than 50 years since the Epstein-Barr virus (EBV), the first human tumour virus, was discovered. EBV has subsequently been found to be associated with a diverse range of tumours of both lymphoid and epithelial origin. Progress in the molecular analysis of EBV has revealed fundamental mechanisms of more general relevance to the oncogenic process. This Timeline article highlights key milestones in the 50-year history of EBV and discusses how this virus provides a paradigm for exploiting insights at the molecular level in the diagnosis, treatment and prevention of cancer.
Collapse
Affiliation(s)
- Lawrence S Young
- Warwick Medical School, The University of Warwick, Coventry CV4 7AL, UK
| | - Lee Fah Yap
- Department of Oral and Craniofacial Sciences and Oral Cancer Research Coordinating Centre, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia
| | - Paul G Murray
- Institute of Cancer and Genomic Medicine, University of Birmingham, Vincent Drive, Edgbaston, Birmingham B15 2TT, UK
| |
Collapse
|
11
|
Incrocci R, Hussain S, Stone A, Bieging K, Alt LAC, Fay MJ, Swanson-Mungerson M. Epstein-Barr virus Latent Membrane Protein 2A (LMP2A)-mediated changes in Fas expression and Fas-dependent apoptosis: Role of Lyn/Syk activation. Cell Immunol 2015; 297:108-19. [PMID: 26255694 DOI: 10.1016/j.cellimm.2015.08.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 07/15/2015] [Accepted: 08/04/2015] [Indexed: 01/01/2023]
Abstract
Epstein-Barr virus Latent Membrane Protein 2A (LMP2A) is expressed in EBV-infected B cells in the germinal center, a site of significant apoptosis induced by engagement of Fas on activated B cells. Signals from the B cell receptor (BCR) protect germinal center B cells from Fas-mediated apoptosis, and since LMP2A is a BCR mimic, we hypothesized that LMP2A would also protect B cells from Fas-mediated apoptosis. Surprisingly, latently-infected human and murine B cell lines expressing LMP2A were more sensitive to Fas-mediated apoptosis, as determined by increases in Annexin-V staining, and cleavage of caspase-8, -3 and PARP. Additional studies show that LMP2A-expressing B cell lines demonstrate a Lyn- and Syk-dependent increase in sensitivity to Fas-mediated apoptosis, due to an LMP2A-dependent enhancement in Fas expression. These findings demonstrate the ability for LMP2A to directly increase a pro-apoptotic molecule and have implications for EBV latency as well as the treatment of EBV-associated malignancies.
Collapse
Affiliation(s)
- Ryan Incrocci
- Chicago College of Osteopathic Medicine, Department of Microbiology and Immunology, 555 31st Street, Downers Grove, IL 60515, USA
| | - Samira Hussain
- College of Health Sciences, Department of Biomedical Sciences, 555 31st Street, Downers Grove, IL 60515, USA
| | - Amanda Stone
- Chicago College of Osteopathic Medicine, Department of Microbiology and Immunology, 555 31st Street, Downers Grove, IL 60515, USA
| | - Kathryn Bieging
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Lauren A C Alt
- College of Health Sciences, Department of Biomedical Sciences, 555 31st Street, Downers Grove, IL 60515, USA
| | - Michael J Fay
- College of Health Sciences, Department of Biomedical Sciences, 555 31st Street, Downers Grove, IL 60515, USA
| | - Michelle Swanson-Mungerson
- Chicago College of Osteopathic Medicine, Department of Microbiology and Immunology, 555 31st Street, Downers Grove, IL 60515, USA.
| |
Collapse
|
12
|
Vockerodt M, Yap LF, Shannon-Lowe C, Curley H, Wei W, Vrzalikova K, Murray PG. The Epstein-Barr virus and the pathogenesis of lymphoma. J Pathol 2015; 235:312-22. [PMID: 25294567 DOI: 10.1002/path.4459] [Citation(s) in RCA: 168] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 10/01/2014] [Accepted: 10/05/2014] [Indexed: 02/06/2023]
Abstract
Since the discovery in 1964 of the Epstein-Barr virus (EBV) in African Burkitt lymphoma, this virus has been associated with a remarkably diverse range of cancer types. Because EBV persists in the B cells of the asymptomatic host, it can easily be envisaged how it contributes to the development of B-cell lymphomas. However, EBV is also found in other cancers, including T-cell/natural killer cell lymphomas and several epithelial malignancies. Explaining the aetiological role of EBV is challenging, partly because the virus probably contributes differently to each tumour and partly because the available disease models cannot adequately recapitulate the subtle variations in the virus-host balance that exist between the different EBV-associated cancers. A further challenge is to identify the co-factors involved; because most persistently infected individuals will never develop an EBV-associated cancer, the virus cannot be working alone. This article will review what is known about the contribution of EBV to lymphoma development.
Collapse
Affiliation(s)
- Martina Vockerodt
- Centre for Human Virology and the School of Cancer Sciences, University of Birmingham, Birmingham, UK
| | | | | | | | | | | | | |
Collapse
|
13
|
Abstract
Latent Epstein–Barr virus (EBV) infection has a substantial role in causing many human disorders. The persistence of these viral genomes in all malignant cells, yet with the expression of limited latent genes, is consistent with the notion that EBV latent genes are important for malignant cell growth. While the EBV-encoded nuclear antigen-1 (EBNA-1) and latent membrane protein-2A (LMP-2A) are critical, the EBNA-leader proteins, EBNA-2, EBNA-3A, EBNA-3C and LMP-1, are individually essential for in vitro transformation of primary B cells to lymphoblastoid cell lines. EBV-encoded RNAs and EBNA-3Bs are dispensable. In this review, the roles of EBV latent genes are summarized.
Collapse
Affiliation(s)
- Myung-Soo Kang
- 1] Samsung Advanced Institute for Health Sciences and Technology (SAIHST), Samsung Medical Center, Sungkyunkwan University, Seoul, Korea [2] Samsung Biomedical Research Institute (SBRI), Samsung Medical Center, Sungkyunkwan University, Seoul, Korea
| | - Elliott Kieff
- Department of Medicine, Brigham and Women's Hospital, Program in Virology, Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA
| |
Collapse
|
14
|
Abstract
Persistent infection by EBV is explained by the germinal center model (GCM) which provides a satisfying and currently the only explanation for EBVs disparate biology. Since the GCM touches on every aspect of the virus, this chapter will serve as an introduction to the subsequent chapters. EBV is B lymphotropic, and its biology closely follows that of normal mature B lymphocytes. The virus persists quiescently in resting memory B cells for the lifetime of the host in a non-pathogenic state that is also invisible to the immune response. To access this compartment, the virus infects naïve B cells in the lymphoepithelium of the tonsils and activates these cells using the growth transcription program. These cells migrate to the GC where they switch to a more limited transcription program, the default program, which helps rescue them into the memory compartment where the virus persists. For egress, the infected memory cells return to the lymphoepithelium where they occasionally differentiate into plasma cells activating viral replication. The released virus can either infect more naïve B cells or be amplified in the epithelium for shedding. This cycle of infection and the quiescent state in memory B cells allow for lifetime persistence at a very low level that is remarkably stable over time. Mathematically, this is a stable fixed point where the mechanisms regulating persistence drive the state back to equilibrium when perturbed. This is the GCM of EBV persistence. Other possible sites and mechanisms of persistence will also be discussed.
Collapse
|
15
|
Mohamed G, Vrzalikova K, Cader FZ, Vockerodt M, Nagy E, Flodr P, Yap LF, Diepstra A, Kluin PM, Rosati S, Murray P. Epstein-Barr virus, the germinal centre and the development of Hodgkin's lymphoma. J Gen Virol 2014; 95:1861-1869. [PMID: 24893782 DOI: 10.1099/vir.0.066712-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The relationship between Epstein-Barr virus (EBV) and the germinal centre (GC) of the asymptomatic host remains an enigma. The occasional appearance of EBV-positive germinal centres in some patients, particularly those with a history of immunosuppression, suggests that EBV numbers in the GC are subject to immune control. The relationship, if any, between lymphoid hyperplasia with EBV-positive germinal centres and subsequent or concurrent lymphomagenesis remains to be clarified. As far as the development of EBV-associated Hodgkin's lymphoma is concerned, the suppression of virus replication, mediated by LMP1 on the one hand, and the loss of B-cell receptor signalling on the other, appears to be an important pathogenic mechanism. A further important emerging concept is that alterations in the microenvironment of the EBV-infected B-cell may be important for lymphomagenesis.
Collapse
Affiliation(s)
- Ghada Mohamed
- Centre for Human Virology and the School of Cancer Sciences, University of Birmingham, Birmingham, UK
| | - Katerina Vrzalikova
- Centre for Human Virology and the School of Cancer Sciences, University of Birmingham, Birmingham, UK
| | - Fathima Zumla Cader
- Centre for Human Virology and the School of Cancer Sciences, University of Birmingham, Birmingham, UK
| | - Martina Vockerodt
- Centre for Human Virology and the School of Cancer Sciences, University of Birmingham, Birmingham, UK
| | - Eszter Nagy
- Centre for Human Virology and the School of Cancer Sciences, University of Birmingham, Birmingham, UK
| | - Patrik Flodr
- Laboratory of Molecular Pathology, Department of Pathology and Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacký University, 77900 Olomouc, Czech Republic
| | - Lee-Fah Yap
- Department of Oral Biology and Biomedical Sciences & Oral Cancer Research and Coordinating Centre, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia
| | - Arjan Diepstra
- University of Groningen and University Medical Centre Groningen Department of Pathology and Medical Biology, Groningen, The Netherlands
| | - Philip M Kluin
- University of Groningen and University Medical Centre Groningen Department of Pathology and Medical Biology, Groningen, The Netherlands
| | - Stefano Rosati
- University of Groningen and University Medical Centre Groningen Department of Pathology and Medical Biology, Groningen, The Netherlands
| | - Paul Murray
- Centre for Human Virology and the School of Cancer Sciences, University of Birmingham, Birmingham, UK
| |
Collapse
|
16
|
Spender LC, Inman GJ. Developments in Burkitt's lymphoma: novel cooperations in oncogenic MYC signaling. Cancer Manag Res 2014; 6:27-38. [PMID: 24426788 PMCID: PMC3890408 DOI: 10.2147/cmar.s37745] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Burkitt's lymphoma (BL) is an aggressive disorder associated with extremely high rates of cell proliferation tempered by high levels of apoptosis. Despite the high levels of cell death, the net effect is one of rapid tumor growth. The tumor arises within the germinal centers of secondary lymphoid tissues and is identifiable by translocation of the c-MYC gene into the immunoglobulin gene loci, resulting in deregulation of the proto-oncogene. Many of the major players involved in determining the development of BL have been characterized in human BL cell lines or in mouse models of MYC-driven lymphomagenesis. Both systems have been useful so far in characterizing the role of tumor suppressor genes (for example, p53), prosurvival signaling pathways, and members of the B-cell lymphoma-2 family of apoptosis regulators in determining the fate of c-MYC overexpressing B-cells, and ultimately in regulating lymphoma development. Signaling through phosphoinositide (PI)3-kinase stands out as being critical for BL cell survival. Recurrent mutations in ID3 or TCF3 (E2A) that promote signaling through PI3-kinase have recently been identified in human BL samples, and new therapeutic strategies based on coordinately targeting both the prosurvival factor, B-cell lymphoma-XL, and the PI3-kinase/AKT/mammalian target of rapamycin (mTOR) signaling pathway to synergistically induced BL apoptosis have been proposed. Now, engineering both constitutive c-MYC expression and PI3-kinase activity, specifically in murine B-cells undergoing the germinal center reaction, has revealed that there is synergistic cooperation between c-MYC and PI3-kinase during BL development. The resulting tumors phenocopy the human malignancy, and acquire tertiary mutations also present in human tumors. This model may, therefore, prove useful in further studies to identify functionally relevant mutational events necessary for BL pathogenesis. This review discusses these cooperating interactions, the possible influence of BL tumor-associated viruses, and highlights potential new opportunities for therapeutic intervention.
Collapse
Affiliation(s)
- Lindsay C Spender
- Division of Cancer Research, Medical Research Institute, Jacqui Wood Cancer Centre, University of Dundee, Ninewells Hospital and Medical School, Dundee, UK
| | - Gareth J Inman
- Division of Cancer Research, Medical Research Institute, Jacqui Wood Cancer Centre, University of Dundee, Ninewells Hospital and Medical School, Dundee, UK
| |
Collapse
|
17
|
Thorley-Lawson DA, Hawkins JB, Tracy SI, Shapiro M. The pathogenesis of Epstein-Barr virus persistent infection. Curr Opin Virol 2013; 3:227-32. [PMID: 23683686 DOI: 10.1016/j.coviro.2013.04.005] [Citation(s) in RCA: 159] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 03/27/2013] [Accepted: 04/15/2013] [Indexed: 11/26/2022]
Abstract
Epstein-Barr virus (EBV) maintains a lifelong infection. According to the germinal center model (GCM), latently infected B cells transit the germinal center (GC) to become resting memory cells. Here, the virus resides quiescently, occasionally reactivating to infect new B cells, completing the cycle of infection. The GCM remains the only model that explains EBV biology and the pathogenesis of lymphoma. Recent work suggests modifications to the model notably that the virus contributes only modestly to the GC process and predictions from mathematical models that quiescence within memory B cells shapes the overall structure of viral infection but is not essential for persistence. Rather, it is the cycle of infection which allows viral persistence at the very low levels observed.
Collapse
Affiliation(s)
- David A Thorley-Lawson
- Department of Pathology, Tufts University School of Medicine, Jaharis Building, Boston, MA 02111, USA.
| | | | | | | |
Collapse
|
18
|
Lossius A, Johansen JN, Torkildsen Ø, Vartdal F, Holmøy T. Epstein-Barr virus in systemic lupus erythematosus, rheumatoid arthritis and multiple sclerosis—association and causation. Viruses 2013; 4:3701-30. [PMID: 23342374 PMCID: PMC3528287 DOI: 10.3390/v4123701] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Epidemiological data suggest that the Epstein-Barr virus (EBV) is associated with several autoimmune diseases, such as systemic lupus erythematosus, rheumatoid arthritis and multiple sclerosis. However, it is not clear whether EBV plays a role in the pathogenesis of these diseases, and if so, by which mechanisms the virus may contribute. In this review, we discuss possible viral and immunological mechanisms that might explain associations between EBV and autoimmune diseases and whether these associations represent causes or effects of inflammation and autoimmunity.
Collapse
Affiliation(s)
- Andreas Lossius
- Institute of Immunology, Oslo University Hospital Rikshospitalet, Oslo, Norway.
| | | | | | | | | |
Collapse
|
19
|
Abstract
Epstein-Barr virus infection has been epidemiologically associated with the development of multiple autoimmune diseases, particularly systemic lupus erythematosus and multiple sclerosis. Currently, there is no known mechanism that can account for these associations. The germinal-center (GC) model of EBV infection and persistence proposes that EBV gains access to the memory B cell compartment via GC reactions by driving infected cells to differentiate using the virus-encoded LMP1 and LMP2a proteins, which act as functional homologues of CD40 and the B cell receptor, respectively. The ability of LMP2a, when expressed in mice, to allow escape of autoreactive B cells suggests that it could perform a similar role in infected GC B cells, permitting the survival of potentially pathogenic autoreactive B cells. To test this hypothesis, we cloned and expressed antibodies from EBV(+) and EBV(-) memory B cells present during acute infection and profiled their self- and polyreactivity. We find that EBV does persist within self- and polyreactive B cells but find no evidence that it favors the survival of pathogenic autoreactive B cells. On the contrary, EBV(+) memory B cells express lower levels of self-reactive and especially polyreactive antibodies than their uninfected counterparts do. Our work suggests that EBV has only a modest effect on the GC process, which allows it to access and persist within a subtly unique niche of the memory compartment characterized by relatively low levels of self- and polyreactivity. We suggest that this might reflect an active process where EBV and its human host have coevolved so as to minimize the virus's potential to contribute to autoimmune disease.
Collapse
|
20
|
Vrazo AC, Chauchard M, Raab-Traub N, Longnecker R. Epstein-Barr virus LMP2A reduces hyperactivation induced by LMP1 to restore normal B cell phenotype in transgenic mice. PLoS Pathog 2012; 8:e1002662. [PMID: 22536156 PMCID: PMC3334893 DOI: 10.1371/journal.ppat.1002662] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Accepted: 03/08/2012] [Indexed: 12/15/2022] Open
Abstract
Epstein-Barr virus (EBV) latently infects most of the human population and is strongly associated with lymphoproliferative disorders. EBV encodes several latency proteins affecting B cell proliferation and survival, including latent membrane protein 2A (LMP2A) and the EBV oncoprotein LMP1. LMP1 and LMP2A signaling mimics CD40 and BCR signaling, respectively, and has been proposed to alter B cell functions including the ability of latently-infected B cells to access and transit the germinal center. In addition, several studies suggested a role for LMP2A modulation of LMP1 signaling in cell lines by alteration of TRAFs, signaling molecules used by LMP1. In this study, we investigated whether LMP1 and LMP2A co-expression in a transgenic mouse model alters B cell maturation and the response to antigen, and whether LMP2A modulates LMP1 function. Naïve LMP1/2A mice had similar lymphocyte populations and antibody production by flow cytometry and ELISA compared to controls. In the response to antigen, LMP2A expression in LMP1/2A animals rescued the impairment in germinal center generation promoted by LMP1. LMP1/2A animals produced high-affinity, class-switched antibody and plasma cells at levels similar to controls. In vitro, LMP1 upregulated activation markers and promoted B cell hyperproliferation, and co-expression of LMP2A restored a wild-type phenotype. By RT-PCR and immunoblot, LMP1 B cells demonstrated TRAF2 levels four-fold higher than non-transgenic controls, and co-expression of LMP2A restored TRAF2 levels to wild-type levels. No difference in TRAF3 levels was detected. While modulation of other TRAF family members remains to be assessed, normalization of the LMP1-induced B cell phenotype through LMP2A modulation of TRAF2 may be a pathway by which LMP2A controls B cell function. These findings identify an advance in the understanding of how Epstein-Barr virus can access the germinal center in vivo, a site critical for both the genesis of immunological memory and of virus-associated tumors. As a ubiquitous human pathogen, Epstein-Barr virus (EBV) infection is associated with several human B cell diseases characterized by inappropriate B cell activation and function, including infectious mononucleosis and certain cancers. EBV latent membrane protein 1 (LMP1) and 2A (LMP2A) hijack cell signaling pathways to alter B cell activation and function, and are detected in EBV-associated diseases. Defining the effect on B cell function when LMP1 and LMP2A are expressed together in the same cell is critical to understanding how EBV subverts normal B cell behavior before disease develops. Using transgenic mice, we have demonstrated that LMP2A dampens cellular proliferation and activation induced by LMP1, which may be due to the LMP2A-associated decrease in the levels of TRAF2, a signaling protein used by LMP1. LMP2A also allows B cells carrying LMP1 to enter the germinal center during an immune response, a site that gives rise to EBV-associated tumors in humans. In sum, this study highlights the biological outcomes of LMP1 and LMP2A co-expression in B cells and contributes to the knowledge of how EBV subverts normal B cell behavior before disease develops.
Collapse
Affiliation(s)
- Alexandra C. Vrazo
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Maria Chauchard
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
- Center for Global Health, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Nancy Raab-Traub
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Richard Longnecker
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
- * E-mail:
| |
Collapse
|
21
|
Epstein-Barr virus latent membrane protein 2A exacerbates experimental autoimmune encephalomyelitis and enhances antigen presentation function. Sci Rep 2012; 2:353. [PMID: 22616025 PMCID: PMC3354779 DOI: 10.1038/srep00353] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2012] [Accepted: 03/13/2012] [Indexed: 11/30/2022] Open
Abstract
Multiple sclerosis (MS) is an inflammatory, autoimmune disease of the central nervous system. The cause of MS is still unknown but epidemiological and immunological studies have implicated Epstein-Barr virus (EBV), which infects B cells, as a possible etiological agent involved in disease. Of particular interest is EBV latent membrane protein 2A (LMP2A) because previous studies have demonstrated that LMP2A enhances the expansion and differentiation of B cells upon antigen stimulation, revealing a potential contribution of this protein in autoimmunity. Since B cells are thought to contribute to MS, we examined the role of LMP2A in the animal model experimental autoimmune encephalomyelitis (EAE). In this model, transgenic mice in which B cells express LMP2A show increased severity and incidence of disease. This difference was not due to lymphocyte recruitment into the CNS or differences in T cell activation, rather, we show that LMP2A enhances antigen presentation function.
Collapse
|
22
|
Murine gammaherpesvirus 68 infection protects lupus-prone mice from the development of autoimmunity. Proc Natl Acad Sci U S A 2012; 109:E1092-100. [PMID: 22474381 DOI: 10.1073/pnas.1203019109] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Gammaherpesvirus infections, such as those caused by EBV, have been suggested to promote the development of autoimmunity. To test this idea, we infected healthy WT and lupus-prone B6.Sle123 mice with an EBV-related and rodent-specific gammaherpesvirus, γHV68. Although acute γHV68 infection increased autoantibody levels for 4 to 6 wk, latent infection inhibited these responses for 1 y. The inhibition of autoantibody expression was only observed in B6.Sle123 females and not in males, which already displayed lower autoantibody titers. Contrary to the initial hypothesis, infection of young B6.Sle123 mice, both male and female, resulted in suppression of lymphoid activation and expansion and of glomerular inflammation and sclerosis, preserving kidney function. Moreover, γHV68 infection led to reduced autoantibody titers, lymphoid activation, and glomerular inflammation whether lupus-prone females were infected before or during disease manifestation. Finally, γHV68 infection also inhibited autoantibody production in the genetically distinct MRL/lpr lupus-prone mice. Our findings indicate that γHV68 infection strongly inhibits the development and progression of lupus-like disease in mice that spontaneously develop this condition mediating its beneficial effects at the humoral, cellular, and organ levels. The mechanisms by which the virus exerts this down-modulatory action are not yet clear, but appear to operate via reduced activation of dendritic cells, T cells, and B cells. Gammaherpesviruses coevolved with the vertebrate immune systems, establishing lifelong infections in humans and other mammals. Our findings that γHV68 infection prevents rather than exacerbates autoimmunity in mice suggest that infection with gammaherpesviruses may be protective rather than pathological in most individuals.
Collapse
|
23
|
A shared gene expression signature in mouse models of EBV-associated and non-EBV-associated Burkitt lymphoma. Blood 2011; 118:6849-59. [PMID: 22039254 DOI: 10.1182/blood-2011-02-338434] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The link between EBV infection and Burkitt lymphoma (BL) is strong, but the mechanism underlying that link has been elusive. We have developed a mouse model for EBV-associated BL in which LMP2A, an EBV latency protein, and MYC are expressed in B cells. Our model has demonstrated the ability of LMP2A to accelerate tumor onset, increase spleen size, and bypass p53 inactivation. Here we describe the results of total gene expression analysis of tumor and pretumor B cells from our transgenic mouse model. Although we see many phenotypic differences and changes in gene expression in pretumor B cells, the transcriptional profiles of tumor cells from LMP2A/λ-MYC and λ-MYC mice are strikingly similar, with fewer than 20 genes differentially expressed. We evaluated the functional significance of one of the most interesting differentially expressed genes, Egr1, and found that it was not required for acceleration of tumor onset by LMP2A. Our studies demonstrate the remarkable ability of LMP2A to affect the pretumor B-cell phenotype and tumorigenesis without substantially altering gene expression in tumor cells.
Collapse
|
24
|
Inhibition of germinal centre apoptotic programmes by epstein-barr virus. Adv Hematol 2011; 2011:829525. [PMID: 22110506 PMCID: PMC3202104 DOI: 10.1155/2011/829525] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Accepted: 07/26/2011] [Indexed: 01/20/2023] Open
Abstract
To establish a persistent latent infection, Epstein-Barr virus (EBV) faces a challenge in that the virus-infected host cell must transit through the germinal centre reaction. This is a site of B cell differentiation where antibody responses are optimised, and the selection criteria for B cells are stringent. The germinal centre environment is harsh, and the vast majority of B cells here die by apoptosis. Only cells receiving adequate survival signals will differentiate fully to be released into the periphery as long-term memory B cells (the site of persistence). In this review, we detail the apoptotic pathways potentially encountered by EBV-infected B cells during the process of infection, and we describe the functions of those EBV-regulated cellular and viral genes that help promote survival of the host B cell.
Collapse
|
25
|
Abstract
NF-κB is a pivotal transcription factor that controls cell survival and proliferation in diverse physiological processes. The activity of NF-κB is tightly controlled through its cytoplasmic sequestration by specific inhibitors, IκBs. Various cellular stimuli induce the activation of an IκB kinase, which phosphorylates IκBs and triggers their proteasomal degradation, causing nuclear translocation of activated NF-κB. Under normal conditions, the activation of NF-κB occurs transiently, thus ensuring rapid but temporary induction of target genes. Deregulated NF-κB activation contributes to the development of various diseases, including cancers and immunological disorders. Accumulated studies demonstrate that the NF-κB signaling pathway is a target of several human oncogenic viruses, including the human T cell leukemia virus type 1, the Kaposi sarcoma-associated herpesvirus, and the Epstein-Bar virus. These viruses encode specific oncoproteins that target different signaling components of the NF-κB pathway, leading to persistent activation of NF-κB. This chapter will discuss the molecular mechanisms by which NF-κB is activated by the viral oncoproteins.
Collapse
Affiliation(s)
- Shao-Cong Sun
- Department of Immunology, The University of Texas MD Anderson Cancer Center and The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, Texas 77030
| | - Ethel Cesarman
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, 1300 York Ave, New York, NY 10065
| |
Collapse
|
26
|
Swanson-Mungerson M, Bultema R, Longnecker R. Epstein-Barr virus LMP2A imposes sensitivity to apoptosis. J Gen Virol 2010; 91:2197-202. [PMID: 20484564 PMCID: PMC3066549 DOI: 10.1099/vir.0.021444-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
In cell lines, the Epstein–Barr virus (EBV)-encoded protein latent membrane protein 2A (LMP2A) protects B-cells from apoptosis by blocking B-cell receptor (BCR) signalling. However, EBV-infected B-cells in vivo are extremely different from cell lines. This study used a murine transgenic model in which B-cells express LMP2A and a BCR specific for hen egg lysozyme to determine whether LMP2A protects resting and antigen-activated B-cells from apoptosis. LMP2A allows BCR signal transduction and induces constitutive activation of NF-κB to increase Bcl-2 levels that afford LMP2A-mediated protection from apoptosis in the absence or presence of antigen. In contrast, low levels of NF-κB inhibitor only affected Bcl-2 and Bcl-xL levels and increased apoptosis in LMP2A-negative B-cells after BCR cross-linking. These data suggest that LMP2A uniquely makes resting B-cells sensitive to NF-κB inhibition and apoptosis and suggest that NF-κB may be a novel target to eradicate latently EBV-infected B-cells.
Collapse
Affiliation(s)
- Michelle Swanson-Mungerson
- Department of Microbiology and Immunology, Chicago College of Osteopathic Medicine, Midwestern University, Downers Grove, IL 60516, USA.
| | | | | |
Collapse
|
27
|
Bieging KT, Swanson-Mungerson M, Amick AC, Longnecker R. Epstein-Barr virus in Burkitt's lymphoma: a role for latent membrane protein 2A. Cell Cycle 2010; 9:901-8. [PMID: 20160479 DOI: 10.4161/cc.9.5.10840] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Burkitt's lymphoma (BL) is characterized by translocation of the MYC gene to an immunoglobulin locus. Transgenic mouse models have been used to study the molecular changes that are necessary to bypass tumor suppression in the presence of translocated MYC. Inactivation of the p53 pathway is a major step to tumor formation in mouse models that is also seen in human disease. Human BL is often highly associated with Epstein-Barr virus (EBV). The EBV latency protein latent membrane protein 2A (LMP2A) is known to promote B cell survival by affecting levels of pro-survival factors. Using LMP2A transgenic mouse models, we have identified a novel mechanism that permits lymphomagenesis in the presence of an intact p53 pathway. This work uncovers a contribution of EBV to molecular events that have documented importance in BL pathogenesis, and may underlie the poorly understood link between EBV and BL.
Collapse
Affiliation(s)
- Kathryn T Bieging
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | | | | | | |
Collapse
|
28
|
Germinal center B cells latently infected with Epstein-Barr virus proliferate extensively but do not increase in number. J Virol 2009; 84:1158-68. [PMID: 19889783 DOI: 10.1128/jvi.01780-09] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
In this study we show that in long-term persistent infection, Epstein-Barr virus (EBV)-infected cells undergoing a germinal center (GC) reaction in the tonsils are limited to the follicles and proliferate extensively. Despite this, the absolute number of infected cells per GC remains small (average of 3 to 4 cells per germinal center; range, 1 to 9 cells), and only about 38 to 55% (average, 45%) of all GCs carry infected cells. The data fit a model where, on average, cells in the GC divide approximately three times; however, only one progeny cell survives to undergo a further three divisions. Thus, a fraction of cells undergo multiple rounds of division without increasing in numbers; i.e., they die at the same rate that they are dividing. We conclude that EBV-infected cells in the GC undergo the extensive proliferation characteristic of GC cells but that the absolute number is limited either by the immune response or by the availability of an essential survival factor. We suggest that this behavior is a relic of the mechanism by which EBV establishes persistence during acute infection. Lastly, the expression of the viral latent protein LMP1 in GC B cells, unlike in vitro, does not correlate directly with the expression of bcl-2 or bcl-6. This emphasizes our claim that observations made regarding the functions of EBV proteins in cell lines or in transgenic mice should be treated with skepticism unless verified in vivo.
Collapse
|
29
|
Epstein-Barr virus LMP2A bypasses p53 inactivation in a MYC model of lymphomagenesis. Proc Natl Acad Sci U S A 2009; 106:17945-50. [PMID: 19815507 DOI: 10.1073/pnas.0907994106] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Although Epstein-Barr virus (EBV) is linked to Burkitt's lymphoma (BL), the role of the virus in lymphomagenesis is unclear. LMP2A, encoded by EBV, can be detected in BL biopsies and has prosurvival functions. We generated mice expressing MYC and LMP2A in B cells. LMP2A/lambda-MYC mice show greatly accelerated tumor onset. Similar to previous work, we found p53 mutations in lambda-MYC tumors; however, we detected no mutations in the rapidly arising LMP2A/lambda-MYC tumors. We further demonstrate that the p53 pathway is functionally intact in LMP2A/lambda-MYC tumors, which have increased levels of PUMA and sensitivity to p53 activation by Nutlin. This work shows that LMP2A can permit tumorigenesis in the presence of an intact p53 pathway, identifying an important contribution of EBV to BL.
Collapse
|
30
|
Abstract
The current model of Epstein-Barr virus (EBV) infection and persistence in vivo proposes that EBV uses the germinal center (the GC model) to establish a quiescent latent infection in otherwise-normal memory B cells. However, the evidence linking EBV-infected cells and the GC is only indirect and limited. Therefore, a key portion of the model, that EBV-infected cells physically reside and participate in GCs, has yet to be verified. Furthermore, recent experiments suggested that upon infection of GC cells the viral growth latency transcription program is dominant and GC functionality and phenotype are ablated, i.e., EBV infection is not consistent with GC function. In this study we show that in vivo, EBV-infected B cells in the tonsils retain expression of functional and phenotypic markers of GC cells, including bcl-6 and AID. Furthermore, these cells are physically located in the GC and express a restricted form of latency, the default latency program. Thus, the EBV default latency transcription program, unlike the growth latency program, is consistent with the retention of GC functionality in vivo. This work verifies key components of the GC model of EBV persistence and suggests that EBV and the GC can interact to produce the latently infected memory cells found in the periphery. Furthermore, it identifies latently infected GC B cells as a potential pathogenic nexus for the development of the EBV-positive, GC-associated lymphomas Hodgkin's disease and Burkitt's lymphoma.
Collapse
|
31
|
Bultema R, Longnecker R, Swanson-Mungerson M. Epstein-Barr virus LMP2A accelerates MYC-induced lymphomagenesis. Oncogene 2009; 28:1471-6. [PMID: 19182823 DOI: 10.1038/onc.2008.492] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Despite the identification of Epstein-Barr virus (EBV) in tumors of Burkitt's lymphoma (BL) over 40 years ago, the exact contribution of EBV to BL is undefined. EBV encodes for multiple proteins in latent B cells that affect B cell survival and activation. One such protein, latent membrane protein 2A (LMP2A), protects B cells from numerous pro-apoptotic stimuli. Therefore, we tested whether LMP2A protects B cells from apoptosis induced by aberrant c-MYC expression that precedes and dominates BL. We crossed LMP2A-transgenic mice (LMP2A-Tg), in which all B cells express LMP2A, to a transgenic mouse that expresses a BL translocation of myc (lambda-MYC-Tg mice). LMP2A promotes proliferation and protects B cells from MYC-induced apoptosis in lambda-MYC-Tg mice. LMP2A also accelerates the development of lymphoma in LMP2A/lambda-MYC-Tg mice. Finally, LMP2A increases the expression of Bcl-X(L) in both pre-tumor B cells and tumor cells, suggesting a mechanism for LMP2A-mediated B cell survival in the presence of MYC. These results support a hypothesis that EBV LMP2A promotes tumor development by protecting pre-tumor B cells that would normally apoptose after the c-myc translocation.
Collapse
Affiliation(s)
- R Bultema
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | | | | |
Collapse
|
32
|
Ikeda M, Longnecker R. The c-Cbl proto-oncoprotein downregulates EBV LMP2A signaling. Virology 2008; 385:183-91. [PMID: 19081591 DOI: 10.1016/j.virol.2008.11.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Revised: 09/28/2008] [Accepted: 11/11/2008] [Indexed: 11/16/2022]
Abstract
Latent membrane protein 2A (LMP2A) of Epstein-Barr virus (EBV) plays a key role in regulating viral latency and EBV pathogenesis by functionally mimicking signals induced by the B-cell receptor (BCR) altering normal B cell development. As c-Cbl ubiquitin ligase (E3) is a critical negative regulator in the BCR signal pathway, the role of c-Cbl in the function and formation of the LMP2A signalosome was examined. c-Cbl promoted LMP2A degradation through ubiquitination, specifically degraded the Syk protein tyrosine kinase in the presence of LMP2A, and inhibited LMP2A induction of the EBV lytic cycle. Our earlier studies indicated that LMP2A-dependent Lyn degradation was mediated by Nedd4-family E3s in LMP2A expressing cells. Combine with these new findings, we propose a model in which c-Cbl and Nedd4-family E3s cooperate to degrade target proteins at discrete steps in the function of the LMP2A signalosome.
Collapse
Affiliation(s)
- Masato Ikeda
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA
| | | |
Collapse
|
33
|
Thorley-Lawson DA, Allday MJ. The curious case of the tumour virus: 50 years of Burkitt's lymphoma. Nat Rev Microbiol 2008; 6:913-24. [PMID: 19008891 DOI: 10.1038/nrmicro2015] [Citation(s) in RCA: 201] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Burkitt's lymphoma (BL) was first described 50 years ago, and the first human tumour virus Epstein-Barr virus (EBV) was discovered in BL tumours soon after. Since then, the role of EBV in the development of BL has become more and more enigmatic. Only recently have we finally begun to understand, at the cellular and molecular levels, the complex and interesting interaction of EBV with B cells that creates a predisposition for the development of BL. Here, we discuss the intertwined histories of EBV and BL and their relationship to the cofactors in BL pathogenesis: malaria and the MYC translocation.
Collapse
Affiliation(s)
- David A Thorley-Lawson
- Department of Pathology, Jaharis Building, Tufts University School of Medicine, 150 Harrison Avenue, Boston, Massachusetts 02111, USA.
| | | |
Collapse
|
34
|
Role of latent membrane protein 2 isoforms in Epstein-Barr virus latency. Trends Microbiol 2008; 16:520-7. [PMID: 18835714 DOI: 10.1016/j.tim.2008.08.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2008] [Revised: 08/27/2008] [Accepted: 08/28/2008] [Indexed: 12/12/2022]
Abstract
The oncogenic Epstein-Barr virus (EBV) infects the majority of the human population without doing harm and establishes a latent infection in the memory B-cell compartment. To accomplish this, EBV hijacks B-cell differentiation pathways and uses its own viral genes to interfere with B-cell signalling to achieve life-long persistence. EBV latent membrane protein 2A (LMP2A) provides a surrogate B-cell receptor signal essential for cell survival and is believed to have a crucial role in the maintenance of latency by blocking B-cell activation which would otherwise lead to lytic EBV infection. These two functions demand tight control of LMP2A activity and expression levels. Based on recent insights in the function of LMP2B, an isoform of LMP2A, we propose a model for how LMP2B modulates the activity of LMP2A contributing to maintenance of EBV latency.
Collapse
|
35
|
Anderson LJ, Longnecker R. EBV LMP2A provides a surrogate pre-B cell receptor signal through constitutive activation of the ERK/MAPK pathway. J Gen Virol 2008; 89:1563-1568. [PMID: 18559925 DOI: 10.1099/vir.0.2008/001461-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Latent membrane protein 2A (LMP2A) of Epstein-Barr virus (EBV) provides developmental and survival signals that mimic those of a B-cell receptor (BCR). Expression of LMP2A during B-cell development results in the ability of B cells to exit the bone marrow in the absence of a BCR and persist in the periphery, where they would normally undergo apoptosis. This study extends the current knowledge of LMP2A function by examining the growth properties of bone marrow B cells from TgE LMP2A mice. Despite the lack of pre-BCR expression, bone marrow B cells from TgE LMP2A mice proliferate and survive in low concentrations of interleukin 7, similar to wild-type cells. Constitutive phosphorylation of ERK/MAPK and PI3K/Akt in TgE LMP2A bone marrow B cells is also reminiscent of signalling through the pre-BCR, altogether demonstrating that LMP2A provides a pre-BCR-like signal to developing B cells.
Collapse
Affiliation(s)
- Leah J Anderson
- Department of Microbiology and Immunology, Northwestern University, Chicago, IL 60611, USA
| | - Richard Longnecker
- Department of Microbiology and Immunology, Northwestern University, Chicago, IL 60611, USA
| |
Collapse
|
36
|
Epstein-Barr virus latent membrane protein 2A preferentially signals through the Src family kinase Lyn. J Virol 2008; 82:8520-8. [PMID: 18579586 DOI: 10.1128/jvi.00843-08] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Latent membrane protein 2A (LMP2A) is a viral protein expressed during Epstein-Barr virus (EBV) latency in EBV-infected B cells both in cell culture and in vivo. LMP2A has important roles in modulating B-cell receptor signal transduction and provides survival and developmental signals to B cells in vivo. Although Lyn has been shown to be important in mediating LMP2A signaling, it is still unclear if Lyn is used preferentially or if LMP2A associates promiscuously with other Src family kinase (SFK) members. To investigate the role of various SFKs in LMP2A signaling, we crossed LMP2A transgenic mice (TgE) with Lyn(-/-), Fyn(-/-), or Blk(-/-) mice. TgE Lyn(-/-) mice had a larger immunoglobulin M (IgM)-positive B-cell population than TgE mice, suggesting that the absence of Lyn prevents LMP2A from delivering survival and developmental signals to the B cells. Both TgE Fyn(-/-) and TgE Blk(-/-) mice have an IgM-negative population of splenic B cells, similar to the TgE mice. LMP2A was also transiently transfected into the human EBV-negative B-cell line BJAB to determine which SFK members associate with LMP2A. Lyn was detected in LMP2A immunoprecipitates, whereas Fyn was not. Both Lyn and Fyn were able to bind to an LMP2A mutant which contained a sequence shown previously to bind tightly to the SH2 domain of multiple SFK members. From these results, we conclude that LMP2A preferentially associates with and signals through Lyn compared to its association with other SFKs. This preferential association is due in part to the SH2 domain of Lyn associating with LMP2A.
Collapse
|
37
|
Shair KHY, Bendt KM, Edwards RH, Bedford EC, Nielsen JN, Raab-Traub N. EBV latent membrane protein 1 activates Akt, NFkappaB, and Stat3 in B cell lymphomas. PLoS Pathog 2008; 3:e166. [PMID: 17997602 PMCID: PMC2065877 DOI: 10.1371/journal.ppat.0030166] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2007] [Accepted: 09/24/2007] [Indexed: 11/18/2022] Open
Abstract
Latent membrane protein 1 (LMP1) is the major oncoprotein of Epstein-Barr virus (EBV). In transgenic mice, LMP1 promotes increased lymphoma development by 12 mo of age. This study reveals that lymphoma develops in B-1a lymphocytes, a population that is associated with transformation in older mice. The lymphoma cells have deregulated cell cycle markers, and inhibitors of Akt, NFκB, and Stat3 block the enhanced viability of LMP1 transgenic lymphocytes and lymphoma cells in vitro. Lymphoma cells are independent of IL4/Stat6 signaling for survival and proliferation, but have constitutively activated Stat3 signaling. These same targets are also deregulated in wild-type B-1a lymphomas that arise spontaneously through age predisposition. These results suggest that Akt, NFκB, and Stat3 pathways may serve as effective targets in the treatment of EBV-associated B cell lymphomas. Epstein-Barr virus (EBV) is linked to the development of multiple cancers, including post-transplant lymphoma, Hodgkin disease, and nasopharyngeal carcinoma. Latent membrane protein 1 (LMP1) is expressed in many EBV-associated cancers and is responsible for most of the altered cellular growth properties that are induced by EBV infection. This study reveals that LMP1 induces lymphomas in B-1a lymphocytes, a cell type that is susceptible to transformation in aged mice. The lymphomas require Akt, NFκB, and Stat3 signaling for enhanced growth and survival. The activation of the Stat3, Akt, and NFκB signaling pathways likely underlies the ability of LMP1 to promote malignant transformation.
Collapse
Affiliation(s)
- Kathy H. Y Shair
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Katherine M Bendt
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Rachel H Edwards
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Elisabeth C Bedford
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Judith N Nielsen
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Nancy Raab-Traub
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Department of Microbiology-Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- * To whom correspondence should be addressed. E-mail:
| |
Collapse
|
38
|
EBV LMP2A affects LMP1-mediated NF-kappaB signaling and survival of lymphoma cells by regulating TRAF2 expression. Blood 2008; 111:3813-20. [PMID: 18230756 DOI: 10.1182/blood-2007-03-080309] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
A mechanism used by Epstein-Barr virus (EBV) for in vitro transformation of B cells into lymphoblastoid cell lines (LCLs) is activation of the NF-kappaB pathway, which is largely mediated by the EBV latent membrane protein 1 (LMP1). LMP1 is coexpressed with LMP2A in many EBV-associated lymphoid malignancies. Since inhibition of NF-kappaB leads to apoptosis of EBV-infected LCLs and lymphoma cell lines, we sought to determine whether LMP1 alone, or in combination with other viral proteins, is responsible for initiating NF-kappaB activation in these cells, thereby playing a role in cell survival. We found that suppression of LMP1 by RNA interference results in inhibition of basal NF-kappaB and induction of apoptosis. Unexpectedly, knockdown of LMP2A also resulted in comparable decrease of NF-kappaB activity and apoptosis. We report that LMP2A protein controls the expression of TRAF2 mRNA, which in turn is necessary for signaling by LMP1. Our data contrast with previous studies showing that transfected LMP1 can signal in the absence of LMP2A or TRAF2, and demonstrate that both LMP2A and TRAF2 are required for survival in naturally infected lymphoma cells and LCLs. These results also support LMP1, LMP2A, and TRAF2 as potential therapeutic targets in a subset of EBV-associated lymphoid malignancies.
Collapse
|
39
|
Souza TA, Stollar BD, Sullivan JL, Luzuriaga K, Thorley-Lawson DA. Influence of EBV on the Peripheral Blood Memory B Cell Compartment. THE JOURNAL OF IMMUNOLOGY 2007; 179:3153-60. [PMID: 17709530 DOI: 10.4049/jimmunol.179.5.3153] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Peripheral blood memory B cells latently infected with EBV bear somatic mutations and are typically isotype switched consistent with being classical Ag-selected memory B cells. In this work, we performed a comparative analysis of the expressed Ig genes between large sets of EBV-infected and uninfected peripheral blood B cells, isolated from the same infectious mononucleosis patients, to determine whether differences exist that could reveal the influence of EBV on the production and maintenance of these cells. We observed that EBV(+) cells on average accumulated more somatic hypermutations than EBV(-) cells. In addition, they had more replacement mutations and a higher replacement-silent ratio of mutations in their CDRs. We also found that EBV occupies a skewed niche within the memory compartment, due to its exclusion from the CD27(+)IgD(+)IgM(+) subset, but this skewing does not affect the overall structure of the compartment. These results indicate that EBV impacts the mutation and selection process of infected cells but that once they enter memory they cannot be distinguished from uninfected cells by host homeostasis mechanisms.
Collapse
Affiliation(s)
- Tatyana A Souza
- Department of Pathology, Jaharis Building, Tufts University School of Medicine, 150 Harrison Avenue, Boston, MA 02111, USA
| | | | | | | | | |
Collapse
|
40
|
Fukuda M, Longnecker R. Epstein-Barr virus latent membrane protein 2A mediates transformation through constitutive activation of the Ras/PI3-K/Akt Pathway. J Virol 2007; 81:9299-306. [PMID: 17582000 PMCID: PMC1951437 DOI: 10.1128/jvi.00537-07] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Epstein-Barr virus (EBV) latent membrane protein 2A (LMP2A) is widely expressed in EBV-infected cells within the infected human host and EBV-associated malignancies, suggesting that LMP2A is important for EBV latency, persistence, and EBV-associated tumorigenesis. Previously, we demonstrated that LMP2A provides an antiapoptotic signal through the activation of phosphatidylinositol 3-kinase (PI3-K)/Akt pathway in vitro. However, the exact function of LMP2A in tumor progression is not well understood. In this study, we found that LMP2A did not induce anchorage-independent cell growth in a human keratinocyte cell line, HaCaT, but did in a human gastric carcinoma cell line, HSC-39. In addition, LMP2A activated the PI3-K/Akt pathway in both HaCaT and HSC-39 cells; however, LMP2A did not activate Ras in HaCaT cells but did in HSC-39 cells. Furthermore, the Ras inhibitors manumycin A and a dominant-negative form of Ras (RasN17) and the PI3-K inhibitor LY294002 blocked LMP2A-mediated Akt phosphorylation and anchorage-independent cell growth in HSC-39 cells. These results suggest that constitutive activation of the Ras/PI3-K/Akt pathway by LMP2A is a key factor for LMP2A-mediated transformation.
Collapse
Affiliation(s)
- Makoto Fukuda
- Department of Microbiology-Immunology, Northwestern University Medical School, 303 E. Chicago Ave., Chicago, IL 60611, USA
| | | |
Collapse
|
41
|
Swanson-Mungerson M, Longnecker R. Epstein–Barr virus latent membrane protein 2A and autoimmunity. Trends Immunol 2007; 28:213-8. [PMID: 17398159 DOI: 10.1016/j.it.2007.03.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2007] [Revised: 02/26/2007] [Accepted: 03/16/2007] [Indexed: 11/18/2022]
Abstract
Epstein-Barr virus (EBV) has been associated with autoimmune diseases for over 40 years. However, the mechanisms by which EBV might promote autoimmune development remain elusive. Many of the hypotheses for the means by which EBV might achieve this incorporate the idea that autoimmune responses are initially immune responses against EBV proteins that crossreact with endogenous human proteins. However, recent evidence using transgenic mouse models suggests that B cells expressing the EBV-encoded protein latent membrane protein 2A (LMP2A) bypasses normal tolerance checkpoints and enhances the development of autoimmune diseases. Evidence from transgenic mouse models supports a paradigm in which LMP2A could promote autoimmune development. This novel model provides a framework to test potential mechanisms by which EBV could promote the development of autoimmune responses and might enable the identification of strategies to treat EBV-associated autoimmune diseases.
Collapse
Affiliation(s)
- Michelle Swanson-Mungerson
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | | |
Collapse
|
42
|
Wang H, Nicholas MW, Conway KL, Sen P, Diz R, Tisch RM, Clarke SH. EBV latent membrane protein 2A induces autoreactive B cell activation and TLR hypersensitivity. THE JOURNAL OF IMMUNOLOGY 2006; 177:2793-802. [PMID: 16920914 DOI: 10.4049/jimmunol.177.5.2793] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
EBV is associated with systemic lupus erythematosus (SLE), but how it might contribute to the etiology is not clear. Since EBV-encoded latent membrane protein 2A (LMP2A) interferes with normal B cell differentiation and function, we sought to determine its effect on B cell tolerance. Mice transgenic for both LMP2A and the Ig transgene 2-12H specific for the ribonucleoprotein Smith (Sm), a target of the immune system in SLE, develop a spontaneous anti-Sm response. LMP2A allows anti-Sm B cells to overcome the regulatory checkpoint at the early preplasma cell stage by a self-Ag-dependent mechanism. LMP2A induces a heightened sensitivity to TLR ligand stimulation, resulting in increased proliferation or Ab-secreting cell differentiation or both. Thus, we propose a model whereby LMP2A induces hypersensitivity to TLR stimulation, leading to activation of anti-Sm B cells through the BCR/TLR pathway. These data further implicate TLRs in the etiology of SLE and suggest a mechanistic link between EBV infection and SLE.
Collapse
Affiliation(s)
- Hongsheng Wang
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC 27599, USA
| | | | | | | | | | | | | |
Collapse
|
43
|
Swanson-Mungerson M, Bultema R, Longnecker R. Epstein-Barr virus LMP2A enhances B-cell responses in vivo and in vitro. J Virol 2006; 80:6764-70. [PMID: 16809282 PMCID: PMC1489056 DOI: 10.1128/jvi.00433-06] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Epstein-Barr virus (EBV) establishes latent infections in a significant percentage of the population. Latent membrane protein 2A (LMP2A) is an EBV protein expressed during latency that inhibits B-cell receptor signaling in lymphoblastoid cell lines. In the present study, we have utilized a transgenic mouse system in which LMP2A is expressed in B cells that are specific for hen egg lysozyme (E/HEL-Tg). To determine if LMP2A allows B cells to respond to antigen, E/HEL-Tg mice were immunized with hen egg lysozyme. E/HEL-Tg mice produced antibody in response to antigen, indicating that LMP2A allows B cells to respond to antigen. In addition, E/HEL-Tg mice produced more antibody and an increased percentage of plasma cells after immunization compared to HEL-Tg littermates, suggesting that LMP2A increased the antibody response in vivo. Finally, in vitro studies determined that LMP2A acts directly on the B cell to increase antibody production by augmenting the expansion and survival of the activated B cells, as well as increasing the percentage of plasma cells generated. Taken together, these data suggest that LMP2A enhances, not diminishes, B-cell-specific antibody responses in vivo and in vitro in the E/HEL-Tg system.
Collapse
Affiliation(s)
- Michelle Swanson-Mungerson
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Ward 6-231, 303 E. Chicago Ave., Chicago, IL 60611, USA
| | | | | |
Collapse
|
44
|
Gauld SB, Merrell KT, Cambier JC. Silencing of autoreactive B cells by anergy: a fresh perspective. Curr Opin Immunol 2006; 18:292-7. [PMID: 16616480 DOI: 10.1016/j.coi.2006.03.015] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2006] [Accepted: 03/28/2006] [Indexed: 12/22/2022]
Abstract
B-cell antigen receptor (BCR) signals are crucial for initiation of humoral immune responses and must be actively modulated and/or terminated in preparation for receipt of subsequent cues for progression. BCR signaling is also actively inhibited in autoreactive cells in which unresponsiveness is maintained by anergy. This serves to prevent cell activation and autoimmunity. Importantly, the feedback mechanisms that modulate and/or terminate signaling during normal antigen-induced B-cell activation appear to also be involved in maintaining B-cell anergy. In fact, it is suggested that anergy reflects nothing more than the normal inability of cells to respond to antigen following preceding stimulation of normal inhibitory feedback mechanisms. Thus, the time-honored two-signal hypothesis is almost certainly correct, with second signals being required to release the cell from inhibitory BCR-specific and trans-active feedback regulation.
Collapse
Affiliation(s)
- Stephen B Gauld
- Integrated Department of Immunology, University of Colorado Health Science Center and National Jewish Medical Research Center, 1400 Jackson Street, Denver, CO 80206, USA
| | | | | |
Collapse
|
45
|
Lu J, Lin WH, Chen SY, Longnecker R, Tsai SC, Chen CL, Tsai CH. Syk tyrosine kinase mediates Epstein-Barr virus latent membrane protein 2A-induced cell migration in epithelial cells. J Biol Chem 2006; 281:8806-14. [PMID: 16431925 DOI: 10.1074/jbc.m507305200] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Although spleen tyrosine kinase (Syk) is known to be important in hematopoietic cell development, the roles of Syk in epithelial cells have not been well studied. Limited data suggest that Syk plays alternate roles in carcinogenesis under different circumstances. In breast cancer, Syk has been suggested to be a tumor suppressor. In contrast, Syk is essential for murine mammary tumor virus-mediated transformation. However, the roles of Syk in tumor migration are still largely unknown. Nasopharyngeal carcinoma, an unusually highly metastatic tumor, expresses Epstein-Barr virus LMP2A (latent membrane protein 2A) in most clinical specimens. Previously, we demonstrated LMP2A triggers epithelial cell migration. LMP2A contains an immunoreceptor tyrosine-based activation motif, which is important for Syk kinase activation in B cells. In this study, we explored whether Syk is important for LMP2A-mediated epithelial cell migration. We demonstrate that LMP2A expression can activate endogenous Syk activity. The activation requires the tyrosine residues in LMP2A ITAM but not YEEA motif, which is important for Syk activation by Lyn in B cells. LMP2A interacts with Syk as demonstrated by coimmunoprecipitation and confocal microscopy. Furthermore, LMP2A-induced cell migration is inhibited by a Syk inhibitor and short interfering RNA. Tyrosines 74 and 85 in the LMP2A immunoreceptor tyrosine-based activation motif are essential for both Syk activation and LMP2A-mediated cell migration, indicating the involvement of Syk in LMP2A-triggered cell migration. The LMP2A-Syk pathway may provide suitable drug targets for treatment of nasopharyngeal carcinoma.
Collapse
Affiliation(s)
- Jean Lu
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei 10063, Taiwan
| | | | | | | | | | | | | |
Collapse
|
46
|
Souza TA, Stollar BD, Sullivan JL, Luzuriaga K, Thorley-Lawson DA. Peripheral B cells latently infected with Epstein-Barr virus display molecular hallmarks of classical antigen-selected memory B cells. Proc Natl Acad Sci U S A 2005; 102:18093-8. [PMID: 16330748 PMCID: PMC1306799 DOI: 10.1073/pnas.0509311102] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2005] [Indexed: 11/18/2022] Open
Abstract
Epstein-Barr virus (EBV) establishes a lifelong persistent infection within peripheral blood B cells with the surface phenotype of memory cells. To date there is no proof that these cells have the genotype of true germinal-center-derived memory B cells. It is critical to understand the relative contribution of viral mimicry versus antigen signaling to the production of these cells because EBV encodes proteins that can affect the surface phenotype of infected cells and provide both T cell help and B cell receptor signals in the absence of cognate antigen. To address these questions we have developed a technique to identify single EBV-infected cells in the peripheral blood and examine their expressed Ig genes. The genes were all isotype-switched and somatically mutated. Furthermore, the mutations do not cause stop codons and display the pattern expected for antigen-selected memory cells based on their frequency, type, and location within the Ig gene. We conclude that latently infected peripheral blood B cells display the molecular hallmarks of classical antigen-selected memory B cells. Therefore, EBV does not disrupt the normal processing of latently infected cells into memory, and deviations from normal B cell biology are not tolerated in the infected cells. This article provides definitive evidence that EBV in the peripheral blood persists in true memory B cells.
Collapse
Affiliation(s)
- Tatyana A Souza
- Department of Pathology, Tufts University School of Medicine, Boston, MA 02111, USA
| | | | | | | | | |
Collapse
|