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Nagatsuka Y, Iwata M, Nagasawa Y, Tsuzuki H, Kitamura N, Komatsu A, Kawana K, Ito R, Fujiwara S, Nakamura H, Takei M. Epstein-barr virus infections induce aberrant osteoclastogenesis in immune system-humanized NOD/Shi-scid/IL-2RγC null mice. Biochem Biophys Res Commun 2024; 715:149984. [PMID: 38688056 DOI: 10.1016/j.bbrc.2024.149984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 04/12/2024] [Accepted: 04/22/2024] [Indexed: 05/02/2024]
Abstract
Epstein-Barr virus (EBV) and other viral infections are possible triggers of autoimmune diseases, such as rheumatoid arthritis (RA). To analyze the causative relationship between EBV infections and RA development, we performed experiment on humanized NOD/Shi-scid/IL-2RγCnull (hu-NOG) mice reconstituted human immune system components and infected with EBV. In EBV-infected hu-NOG mice, breakdown of knee joint bones was found to be accompanied by the accumulation of receptor activator of nuclear factor-κB (NF-κB) (RANK) ligand (RANKL), a key factor in osteoclastogenesis, human CD19 and EBV-encoded small RNA (EBER)-bearing cells. Accumulation of these cells expanded in the bone marrow adjacent to the bone breakage, showing a histological feature like to that in bone marrow edema. On the other hand, human RANK/human matrix metalloprotease-9 (MMP-9) positive, osteoclast-like cells were found at broken bone portion of EBV-infected mouse knee joint. In addition, human macrophage-colony stimulating factor (M-CSF), an essential factor in development of osteoclasts, evidently expressed in spleen and bone marrow of EBV-infected humanized mice. Furthermore, RANKL and M-CSF were identified at certain period of EBV-transformed B lymphoblastoid cells (BLBCs) derived from umbilical cord blood lymphocytes. Co-culturing bone marrow cells of hu-NOG mice with EBV-transformed BLBCs resulted in the induction of a multinucleated cell population positive for tartrate-resistant acid phosphatase and human MMP-9 which indicating human osteoclast-like cells. These findings suggest that EBV-infected BLBCs induce human aberrant osteoclastogenesis, which cause erosive arthritis in the joints.
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Affiliation(s)
- Yasuko Nagatsuka
- Department of Medicine, Division of Hematology and Rheumatology, Nihon University, Japan.
| | - Mitsuhiro Iwata
- Department of Medicine, Division of Hematology and Rheumatology, Nihon University, Japan.
| | - Yosuke Nagasawa
- Department of Medicine, Division of Hematology and Rheumatology, Nihon University, Japan.
| | - Hiroshi Tsuzuki
- Department of Medicine, Division of Hematology and Rheumatology, Nihon University, Japan.
| | - Noboru Kitamura
- Department of Medicine, Division of Hematology and Rheumatology, Nihon University, Japan.
| | - Atsushi Komatsu
- Department of Medicine, Division of Obstetrics and Gynecology, Nihon University, Japan.
| | - Kei Kawana
- Department of Medicine, Division of Obstetrics and Gynecology, Nihon University, Japan.
| | - Ryoji Ito
- Department of Immunology, Central Institute for Experimental Animals, Japan.
| | | | - Hideki Nakamura
- Department of Medicine, Division of Hematology and Rheumatology, Nihon University, Japan.
| | - Masami Takei
- Department of Medicine, Division of Hematology and Rheumatology, Nihon University, Japan.
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2
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Nanbo A. Current Insights into the Maturation of Epstein-Barr Virus Particles. Microorganisms 2024; 12:806. [PMID: 38674750 PMCID: PMC11051851 DOI: 10.3390/microorganisms12040806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 04/12/2024] [Accepted: 04/15/2024] [Indexed: 04/28/2024] Open
Abstract
The three subfamilies of herpesviruses (alphaherpesviruses, betaherpesviruses, and gammaherpesviruses) appear to share a unique mechanism for the maturation and egress of virions, mediated by several budding and fusion processes of various organelle membranes during replication, which prevents cellular membrane disruption. Newly synthesized viral DNA is packaged into capsids within the nucleus, which are subsequently released into the cytoplasm via sequential fusion (primary envelopment) and budding through the inner and outer nuclear membranes. Maturation concludes with tegumentation and the secondary envelopment of nucleocapsids, which are mediated by budding into various cell organelles. Intracellular compartments containing mature virions are transported to the plasma membrane via host vesicular trafficking machinery, where they fuse with the plasma membrane to extracellularly release mature virions. The entire process of viral maturation is orchestrated by sequential interactions between viral proteins and intracellular membranes. Compared with other herpesvirus subfamilies, the mechanisms of gammaherpesvirus maturation and egress remain poorly understood. This review summarizes the major findings, including recently updated information of the molecular mechanism underlying the maturation and egress process of the Epstein-Barr virus, a ubiquitous human gammaherpesvirus subfamily member that infects most of the population worldwide and is associated with a number of human malignancies.
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Affiliation(s)
- Asuka Nanbo
- National Research Center for the Control and Prevention of Infectious Diseases, Nagasaki University, Nagasaki 852-8523, Japan
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3
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Bristol JA, Nelson SE, Ohashi M, Casco A, Hayes M, Ranheim EA, Pawelski AS, Singh DR, Hodson DJ, Johannsen EC, Kenney SC. Latent Epstein-Barr virus infection collaborates with Myc over-expression in normal human B cells to induce Burkitt-like Lymphomas in mice. PLoS Pathog 2024; 20:e1012132. [PMID: 38620028 PMCID: PMC11045125 DOI: 10.1371/journal.ppat.1012132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 04/25/2024] [Accepted: 03/18/2024] [Indexed: 04/17/2024] Open
Abstract
Epstein-Barr virus (EBV) is an important cause of human lymphomas, including Burkitt lymphoma (BL). EBV+ BLs are driven by Myc translocation and have stringent forms of viral latency that do not express either of the two major EBV oncoproteins, EBNA2 (which mimics Notch signaling) and LMP1 (which activates NF-κB signaling). Suppression of Myc-induced apoptosis, often through mutation of the TP53 (p53) gene or inhibition of pro-apoptotic BCL2L11 (BIM) gene expression, is required for development of Myc-driven BLs. EBV+ BLs contain fewer cellular mutations in apoptotic pathways compared to EBV-negative BLs, suggesting that latent EBV infection inhibits Myc-induced apoptosis. Here we use an EBNA2-deleted EBV virus (ΔEBNA2 EBV) to create the first in vivo model for EBV+ BL-like lymphomas derived from primary human B cells. We show that cord blood B cells infected with both ΔEBNA2 EBV and a Myc-expressing vector proliferate indefinitely on a CD40L/IL21 expressing feeder layer in vitro and cause rapid onset EBV+ BL-like tumors in NSG mice. These LMP1/EBNA2-negative Myc-driven lymphomas have wild type p53 and very low BIM, and express numerous germinal center B cell proteins (including TCF3, BACH2, Myb, CD10, CCDN3, and GCSAM) in the absence of BCL6 expression. Myc-induced activation of Myb mediates expression of many of these BL-associated proteins. We demonstrate that Myc blocks LMP1 expression both by inhibiting expression of cellular factors (STAT3 and Src) that activate LMP1 transcription and by increasing expression of proteins (DNMT3B and UHRF1) known to enhance DNA methylation of the LMP1 promoters in human BLs. These results show that latent EBV infection collaborates with Myc over-expression to induce BL-like human B-cell lymphomas in mice. As NF-κB signaling retards the growth of EBV-negative BLs, Myc-mediated repression of LMP1 may be essential for latent EBV infection and Myc translocation to collaboratively induce human BLs.
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Affiliation(s)
- Jillian A. Bristol
- Department of Oncology, McArdle Laboratory for Cancer Research, School of Medicine and Public Health, University of Wisconsin Madison, Madison, Wisconsin, United States of America
| | - Scott E. Nelson
- Department of Oncology, McArdle Laboratory for Cancer Research, School of Medicine and Public Health, University of Wisconsin Madison, Madison, Wisconsin, United States of America
| | - Makoto Ohashi
- Department of Oncology, McArdle Laboratory for Cancer Research, School of Medicine and Public Health, University of Wisconsin Madison, Madison, Wisconsin, United States of America
| | - Alejandro Casco
- Department of Oncology, McArdle Laboratory for Cancer Research, School of Medicine and Public Health, University of Wisconsin Madison, Madison, Wisconsin, United States of America
| | - Mitchell Hayes
- Department of Oncology, McArdle Laboratory for Cancer Research, School of Medicine and Public Health, University of Wisconsin Madison, Madison, Wisconsin, United States of America
| | - Erik A. Ranheim
- Department of Pathology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Abigail S. Pawelski
- Department of Oncology, McArdle Laboratory for Cancer Research, School of Medicine and Public Health, University of Wisconsin Madison, Madison, Wisconsin, United States of America
| | - Deo R. Singh
- Department of Oncology, McArdle Laboratory for Cancer Research, School of Medicine and Public Health, University of Wisconsin Madison, Madison, Wisconsin, United States of America
| | - Daniel J. Hodson
- Wellcome-MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge, United Kingdom
| | - Eric C. Johannsen
- Department of Oncology, McArdle Laboratory for Cancer Research, School of Medicine and Public Health, University of Wisconsin Madison, Madison, Wisconsin, United States of America
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Shannon C. Kenney
- Department of Oncology, McArdle Laboratory for Cancer Research, School of Medicine and Public Health, University of Wisconsin Madison, Madison, Wisconsin, United States of America
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
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4
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Dai YC, Yeh SY, Cheng YY, Huang WH, Liou GG, Yang TY, Chang CY, Fang TF, Chang CW, Su MT, Lee CP, Chen MR. BGLF4 kinase regulates the formation of the EBV cytoplasmic assembly compartment and the recruitment of cellular IQGAP1 for virion release. J Virol 2024; 98:e0189923. [PMID: 38294245 PMCID: PMC10878254 DOI: 10.1128/jvi.01899-23] [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: 12/05/2023] [Accepted: 12/26/2023] [Indexed: 02/01/2024] Open
Abstract
After Epstein-Barr virus (EBV) genome replication and encapsidation in the nucleus, nucleocapsids are translocated into the cytoplasm for subsequent tegumentation and maturation. The EBV BGLF4 kinase, which induces partial disassembly of the nuclear lamina, and the nuclear egress complex BFRF1/BFLF2 coordinately facilitate the nuclear egress of nucleocapsids. Here, we demonstrate that within EBV reactivated epithelial cells, viral capsids, tegument proteins, and glycoproteins are clustered in the juxtanuclear concave region, accompanied by redistributed cytoplasmic organelles and the cytoskeleton regulator IQ-domain GTPase-activation protein 1 (IQGAP1), close to the microtubule-organizing center (MTOC). The assembly compartment (AC) structure was diminished in BGLF4-knockdown TW01-EBV cells and BGLF4-knockout bacmid-carrying TW01 cells, suggesting that the formation of AC structure is BGLF4-dependent. Notably, glycoprotein gp350/220 was observed by confocal imaging to be distributed in the perinuclear concave region and surrounded by the endoplasmic reticulum (ER) membrane marker calnexin, indicating that the AC may be located within a globular structure derived from ER membranes, adjacent to the outer nuclear membrane. Moreover, the viral capsid protein BcLF1 and tegument protein BBLF1 were co-localized with IQGAP1 near the cytoplasmic membrane in the late stage of replication. Knockdown of IQGAP1 did not affect the AC formation but decreased virion release from both TW01-EBV and Akata+ cells, suggesting IQGAP1-mediated trafficking regulates EBV virion release. The data presented here show that BGLF4 is required for cytoskeletal rearrangement, coordination with the redistribution of cytoplasmic organelles and IQGAP1 for virus maturation, and subsequent IQGAP1-dependent virion release.IMPORTANCEEBV genome is replicated and encapsidated in the nucleus, and the resultant nucleocapsids are translocated to the cytoplasm for subsequent virion maturation. We show that a cytoplasmic AC, containing viral proteins, markers of the endoplasmic reticulum, Golgi, and endosomes, is formed in the juxtanuclear region of epithelial and B cells during EBV reactivation. The viral BGLF4 kinase contributes to the formation of the AC. The cellular protein IQGAP1 is also recruited to the AC and partially co-localizes with the virus capsid protein BcLF1 and tegument protein BBLF1 in EBV-reactivated cells, dependent on the BGLF4-induced cytoskeletal rearrangement. In addition, virion release was attenuated in IQGAP1-knockdown epithelial and B cells after reactivation, suggesting that IQGAP1-mediated trafficking may regulate the efficiency of virus maturation and release.
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Affiliation(s)
- Yu-Ching Dai
- Graduate Institute and Department of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Szu-Yun Yeh
- Graduate Institute and Department of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yi-Ying Cheng
- Graduate Institute and Department of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Wei-Han Huang
- Graduate Institute and Department of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Gunn-Guang Liou
- Office of Research and Development, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Tsung-Yu Yang
- Graduate Institute and Department of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chao-Yuan Chang
- Graduate Institute and Department of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Tien-Fang Fang
- Graduate Institute and Department of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chou-Wei Chang
- Graduate Institute and Department of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Mei-Tzu Su
- Graduate Institute and Department of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chung-Pei Lee
- School of Nursing, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan
| | - Mei-Ru Chen
- Graduate Institute and Department of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
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5
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Mitra B, Beri NR, Guo R, Burton EM, Murray-Nerger LA, Gewurz BE. Characterization of target gene regulation by the two Epstein-Barr virus oncogene LMP1 domains essential for B-cell transformation. mBio 2023; 14:e0233823. [PMID: 38009935 PMCID: PMC10746160 DOI: 10.1128/mbio.02338-23] [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: 08/31/2023] [Accepted: 10/09/2023] [Indexed: 11/29/2023] Open
Abstract
IMPORTANCE Epstein-Barr virus (EBV) causes multiple human cancers, including B-cell lymphomas. In cell culture, EBV converts healthy human B-cells into immortalized ones that grow continuously, which model post-transplant lymphomas. Constitutive signaling from two cytoplasmic tail domains of the EBV oncogene latent membrane protein 1 (LMP1) is required for this transformation, yet there has not been systematic analysis of their host gene targets. We identified that only signaling from the membrane proximal domain is required for survival of these EBV-immortalized cells and that its loss triggers apoptosis. We identified key LMP1 target genes, whose abundance changed significantly with loss of LMP1 signals, or that were instead upregulated in response to switching on signaling by one or both LMP1 domains in an EBV-uninfected human B-cell model. These included major anti-apoptotic factors necessary for EBV-infected B-cell survival. Bioinformatics analyses identified clusters of B-cell genes that respond differently to signaling by either or both domains.
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Affiliation(s)
- Bidisha Mitra
- Division of Infectious Diseases, Department of Medicine, Brigham and Women’s Hospital, Boston, Massachusetts, USA
- Center for Integrated Solutions for Infectious Disease, Broad Institute of Harvard and MIT, Cambridge, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Nina Rose Beri
- Division of Infectious Diseases, Department of Medicine, Brigham and Women’s Hospital, Boston, Massachusetts, USA
- Center for Integrated Solutions for Infectious Disease, Broad Institute of Harvard and MIT, Cambridge, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Rui Guo
- Division of Infectious Diseases, Department of Medicine, Brigham and Women’s Hospital, Boston, Massachusetts, USA
- Center for Integrated Solutions for Infectious Disease, Broad Institute of Harvard and MIT, Cambridge, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Eric M. Burton
- Division of Infectious Diseases, Department of Medicine, Brigham and Women’s Hospital, Boston, Massachusetts, USA
- Center for Integrated Solutions for Infectious Disease, Broad Institute of Harvard and MIT, Cambridge, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Laura A. Murray-Nerger
- Division of Infectious Diseases, Department of Medicine, Brigham and Women’s Hospital, Boston, Massachusetts, USA
- Center for Integrated Solutions for Infectious Disease, Broad Institute of Harvard and MIT, Cambridge, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Benjamin E. Gewurz
- Division of Infectious Diseases, Department of Medicine, Brigham and Women’s Hospital, Boston, Massachusetts, USA
- Center for Integrated Solutions for Infectious Disease, Broad Institute of Harvard and MIT, Cambridge, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
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6
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Huang WH, Su WM, Wang CW, Fang YH, Jian YW, Hsu HJ, Peng CW. Momordica anti-HIV protein MAP30 abrogates the Epstein-Barr virus nuclear antigen 1 dependent functions in host cells. Heliyon 2023; 9:e21486. [PMID: 38027600 PMCID: PMC10660024 DOI: 10.1016/j.heliyon.2023.e21486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 09/07/2023] [Accepted: 10/22/2023] [Indexed: 12/01/2023] Open
Abstract
Originally extracted from Momordica charantia seeds, the antiviral and anti-tumor activities of Momordica anti-HIV protein MAP30 have become well known. Although MAP30 has been reported to possess antiviral activity against several human viruses, the current understanding of the MAP30-mediated antiviral response is mainly derived from the previous research work on anti-HIV herbal medicines; the mechanistic insight of its effects on other viruses remains largely unknown. In this study, we showed that both ectopically expressed and purified recombinant MAP30 (rMAP30) impeded Epstein-Barr virus Nuclear Antigen 1 (EBNA1)-mediated transcription from the viral latent replication origin. Mechanistically, in vivo and in vitro studies revealed that MAP30 caused EBNA1 to dissociate from the cognate binding sites, which disrupted downstream EBNA1-dependent viral epigenome accumulation and cell maintenance of Epstein-Barr virus (EBV)-associated neoplastic cells. Finally, mutational analysis indicated that the N-terminal ricin A homologous domain shared by ricin-like proteins was implicated in the anti-EBV response. Our study provides evidence to support that MAP30 has a unique property to combat EBV latent infection, suggesting a potential to develop this herbal protein to be an alternative medicine for EBV associated diseases.
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Affiliation(s)
- Wei-Hang Huang
- Department of Clinical Pathology Department of Hematology & Oncology, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, 97002 Taiwan
- Institute of Medical Sciences, Tzu Chi University, Hualien 97004, Taiwan
| | - Wen-Min Su
- Department of Life Science, National Dong-Hwa University, Shoufeng, Hualien, 974301 Taiwan
| | - Chung-Wei Wang
- Department of Life Science, National Dong-Hwa University, Shoufeng, Hualien, 974301 Taiwan
| | - Yue-Hao Fang
- Institute of Medical Sciences, Tzu Chi University, Hualien 97004, Taiwan
| | - Yuan-Wei Jian
- Department of Life Sciences, Tzu Chi University, Hualien, 97004 Taiwan
| | - Hao-Jen Hsu
- Department of Life Sciences, Tzu Chi University, Hualien, 97004 Taiwan
| | - Chih-Wen Peng
- Department of Life Science, National Dong-Hwa University, Shoufeng, Hualien, 974301 Taiwan
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7
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De La Cruz-Herrera CF, Tatham MH, Siddiqi UZ, Shire K, Marcon E, Greenblatt JF, Hay RT, Frappier L. Changes in SUMO-modified proteins in Epstein-Barr virus infection identifies reciprocal regulation of TRIM24/28/33 complexes and the lytic switch BZLF1. PLoS Pathog 2023; 19:e1011477. [PMID: 37410772 DOI: 10.1371/journal.ppat.1011477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 06/12/2023] [Indexed: 07/08/2023] Open
Abstract
SUMO modifications regulate the function of many proteins and are important in controlling herpesvirus infections. We performed a site-specific proteomic analysis of SUMO1- and SUMO2-modified proteins in Epstein-Barr virus (EBV) latent and lytic infection to identify proteins that change in SUMO modification status in response to EBV reactivation. Major changes were identified in all three components of the TRIM24/TRIM28/TRIM33 complex, with TRIM24 being rapidly degraded and TRIM33 being phosphorylated and SUMOylated in response to EBV lytic infection. Further experiments revealed TRIM24 and TRIM33 repress expression of the EBV BZLF1 lytic switch gene, suppressing EBV reactivation. However, BZLF1 was shown to interact with TRIM24 and TRIM33, resulting in disruption of TRIM24/TRIM28/TRIM33 complexes, degradation of TRIM24 and modification followed by degradation of TRIM33. Therefore, we have identified TRIM24 and TRIM33 as cellular antiviral defence factors against EBV lytic infection and established the mechanism by which BZLF1 disables this defence.
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Affiliation(s)
| | - Michael H Tatham
- Division of Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Umama Z Siddiqi
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Kathy Shire
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Edyta Marcon
- Donnelly Centre, University of Toronto, Toronto, Canada
| | - Jack F Greenblatt
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
- Donnelly Centre, University of Toronto, Toronto, Canada
| | - Ronald T Hay
- Division of Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Lori Frappier
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
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8
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Roche KL, Remiszewski S, Todd MJ, Kulp JL, Tang L, Welsh AV, Barry AP, De C, Reiley WW, Wahl A, Garcia JV, Luftig MA, Shenk T, Tonra JR, Murphy EA, Chiang LW. An allosteric inhibitor of sirtuin 2 deacetylase activity exhibits broad-spectrum antiviral activity. J Clin Invest 2023; 133:e158978. [PMID: 37317966 PMCID: PMC10266789 DOI: 10.1172/jci158978] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 05/02/2023] [Indexed: 06/16/2023] Open
Abstract
Most drugs used to treat viral disease target a virus-coded product. They inhibit a single virus or virus family, and the pathogen can readily evolve resistance. Host-targeted antivirals can overcome these limitations. The broad-spectrum activity achieved by host targeting can be especially useful in combating emerging viruses and for treatment of diseases caused by multiple viral pathogens, such as opportunistic agents in immunosuppressed patients. We have developed a family of compounds that modulate sirtuin 2, an NAD+-dependent deacylase, and now report the properties of a member of that family, FLS-359. Biochemical and x-ray structural studies show that the drug binds to sirtuin 2 and allosterically inhibits its deacetylase activity. FLS-359 inhibits the growth of RNA and DNA viruses, including members of the coronavirus, orthomyxovirus, flavivirus, hepadnavirus, and herpesvirus families. FLS-359 acts at multiple levels to antagonize cytomegalovirus replication in fibroblasts, causing modest reductions in viral RNAs and DNA, together with a much greater reduction in infectious progeny, and it exhibits antiviral activity in humanized mouse models of infection. Our results highlight the potential of sirtuin 2 inhibitors as broad-spectrum antivirals and set the stage for further understanding of how host epigenetic mechanisms impact the growth and spread of viral pathogens.
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Affiliation(s)
- Kathryn L. Roche
- Evrys Bio LLC, Pennsylvania Biotechnology Center, Doylestown, Pennsylvania, USA
| | - Stacy Remiszewski
- Evrys Bio LLC, Pennsylvania Biotechnology Center, Doylestown, Pennsylvania, USA
| | - Matthew J. Todd
- Evrys Bio LLC, Pennsylvania Biotechnology Center, Doylestown, Pennsylvania, USA
| | - John L. Kulp
- Evrys Bio LLC, Pennsylvania Biotechnology Center, Doylestown, Pennsylvania, USA
| | - Liudi Tang
- Evrys Bio LLC, Pennsylvania Biotechnology Center, Doylestown, Pennsylvania, USA
| | - Alison V. Welsh
- Evrys Bio LLC, Pennsylvania Biotechnology Center, Doylestown, Pennsylvania, USA
| | - Ashley P. Barry
- Department of Molecular Genetics and Microbiology, Duke Center for Virology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Chandrav De
- International Center for the Advancement of Translational Science, Division of Infectious Diseases, Center for AIDS Research, University of North Carolina, School of Medicine, Chapel Hill, North Carolina, USA
| | | | - Angela Wahl
- International Center for the Advancement of Translational Science, Division of Infectious Diseases, Center for AIDS Research, University of North Carolina, School of Medicine, Chapel Hill, North Carolina, USA
| | - J. Victor Garcia
- International Center for the Advancement of Translational Science, Division of Infectious Diseases, Center for AIDS Research, University of North Carolina, School of Medicine, Chapel Hill, North Carolina, USA
| | - Micah A. Luftig
- Department of Molecular Genetics and Microbiology, Duke Center for Virology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Thomas Shenk
- Evrys Bio LLC, Pennsylvania Biotechnology Center, Doylestown, Pennsylvania, USA
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
| | - James R. Tonra
- Evrys Bio LLC, Pennsylvania Biotechnology Center, Doylestown, Pennsylvania, USA
| | - Eain A. Murphy
- Evrys Bio LLC, Pennsylvania Biotechnology Center, Doylestown, Pennsylvania, USA
- Microbiology and Immunology Department, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Lillian W. Chiang
- Evrys Bio LLC, Pennsylvania Biotechnology Center, Doylestown, Pennsylvania, USA
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9
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Saikumar Lakshmi P, Oduor CI, Forconi CS, M'Bana V, Bly C, Gerstein RM, Otieno JA, Ong'echa JM, Münz C, Luftig MA, Brehm MA, Bailey JA, Moormann AM. Endemic Burkitt lymphoma avatar mouse models for exploring inter-patient tumor variation and testing targeted therapies. Life Sci Alliance 2023; 6:e202101355. [PMID: 36878637 PMCID: PMC9990458 DOI: 10.26508/lsa.202101355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Revised: 01/31/2023] [Accepted: 02/01/2023] [Indexed: 03/08/2023] Open
Abstract
Endemic Burkitt lymphoma (BL) is a childhood cancer in sub-Saharan Africa characterized by Epstein-Barr virus and malaria-associated aberrant B-cell activation and MYC chromosomal translocation. Survival rates hover at 50% after conventional chemotherapies; therefore, clinically relevant models are necessary to test additional therapies. Hence, we established five patient-derived BL tumor cell lines and corresponding NSG-BL avatar mouse models. Transcriptomics confirmed that our BL lines maintained fidelity from patient tumors to NSG-BL tumors. However, we found significant variation in tumor growth and survival among NSG-BL avatars and in Epstein-Barr virus protein expression patterns. We tested rituximab responsiveness and found one NSG-BL model exhibiting direct sensitivity, characterized by apoptotic gene expression counterbalanced by unfolded protein response and mTOR pro-survival pathways. In rituximab-unresponsive tumors, we observed an IFN-α signature confirmed by the expression of IRF7 and ISG15. Our results demonstrate significant inter-patient tumor variation and heterogeneity, and that contemporary patient-derived BL cell lines and NSG-BL avatars are feasible tools to guide new therapeutic strategies and improve outcomes for these children.
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Affiliation(s)
- Priya Saikumar Lakshmi
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Cliff I Oduor
- Department of Pathology and Laboratory Medicine, Warren Alpert Medical School, Brown University, Providence, RI, USA
| | - Catherine S Forconi
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Viriato M'Bana
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Courtney Bly
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Rachel M Gerstein
- Department of Microbiology and Physiological Systems, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Juliana A Otieno
- Jaramogi Oginga Odinga Teaching and Referral Hospital, Ministry of Medical Services, Kisumu, Kenya
| | - John M Ong'echa
- Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Christian Münz
- Department of Viral Immunobiology, Institute of Experimental Immunology, University of Zürich, Zurich, Switzerland
| | - Micah A Luftig
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC, USA
| | - Michael A Brehm
- Program in Molecular Medicine and the Diabetes Center of Excellence, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Jeffrey A Bailey
- Department of Pathology and Laboratory Medicine, Warren Alpert Medical School, Brown University, Providence, RI, USA
| | - Ann M Moormann
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
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10
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Jhang JF, Liu CD, Hsu YH, Chen CC, Chen HC, Jiang YH, Wu WC, Peng CW, Kuo HC. EBV infection mediated BDNF expression is associated with bladder inflammation in interstitial cystitis/bladder pain syndrome with Hunner's lesion. J Pathol 2023; 259:276-290. [PMID: 36441149 DOI: 10.1002/path.6040] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 10/31/2022] [Accepted: 11/24/2022] [Indexed: 11/30/2022]
Abstract
Interstitial cystitis/bladder pain syndrome with Hunner's lesion (HIC) is characterized by chronic inflammation and nerve hyperplasia; however, the pathogenesis of HIC remains a mystery. In this study, we detected both Epstein-Barr virus (EBV) latency infection genes EBNA-1 and LMP-1 and EBV lytic infection BZLF-1 and BRLF-1 expression in the HIC bladders, indicating the coexistence of EBV persistence and reactivation in the B cells in HIC bladders. Upregulation of EBV-associated inflammatory genes in HIC bladders, such as TNF-α and IL-6, suggests EBV infection is implicated in the pathogenesis of bladder inflammation. Nerve hyperplasia and upregulation of brain-derived neurotrophic factor (BDNF) were noted in the HIC bladders. Double immunochemical staining and flow cytometry revealed the origin of BDNF to be EBV-infected B cells. Inducible BDNF expression was noted in B cells upon EBV infection, but not in the T cells. A chromatin immunoprecipitation study revealed BDNF transcription could be promoted by cooperation between EBV nuclear antigens, chromatin modifiers, and B-cell-specific transcription. Knockdown of BDNF in EBV-infected B cells resulted in the inhibition of cell proliferation and viability. Downregulation of phosphorylated SMAD2 and STAT3 after BDNF knockdown may play a role in the mechanism. Implantation of latent EBV-infected B cells into rat bladder walls resulted in a higher expression level of CD45 and PGP9.5, suggesting tissue inflammation and nerve hyperplasia. In contrast, implantation of BDNF depleted EBV-infected B cells abrogated these effects. This is the first study to provide insights into the mechanisms underlying the involvement of EBV-infected B cells in HIC pathogenesis. © 2022 The Pathological Society of Great Britain and Ireland.
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Affiliation(s)
- Jia-Fong Jhang
- Department of Urology, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan.,Department of Urology, School of Medicine, Tzu Chi University, Hualien, Taiwan.,Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan
| | - Cheng-Der Liu
- Department of Life Science, National Donghwa University, Shoufeng, Taiwan
| | - Yung-Hsiang Hsu
- Department of Pathology, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan.,Department of Pathology, School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Chien-Chin Chen
- Department of Pathology, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi, Taiwan.,Department of Cosmetic Science, Chia Nan University of Pharmacy and Science, Tainan, Taiwan.,Department of Biotechnology and Bioindustry Sciences, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan
| | - Hsiang-Chin Chen
- Department of Life Science, National Donghwa University, Shoufeng, Taiwan
| | - Yuan-Hong Jiang
- Department of Urology, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan.,Department of Urology, School of Medicine, Tzu Chi University, Hualien, Taiwan.,Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan
| | - Wan-Chen Wu
- Department of Life Science, National Donghwa University, Shoufeng, Taiwan
| | - Chih-Wen Peng
- Department of Life Science, National Donghwa University, Shoufeng, Taiwan
| | - Hann-Chorng Kuo
- Department of Urology, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan.,Department of Urology, School of Medicine, Tzu Chi University, Hualien, Taiwan.,Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan
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11
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Hayman IR, Temple RM, Burgess CK, Ferguson M, Liao J, Meyers C, Sample CE. New insight into Epstein-Barr virus infection using models of stratified epithelium. PLoS Pathog 2023; 19:e1011040. [PMID: 36630458 PMCID: PMC9873185 DOI: 10.1371/journal.ppat.1011040] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 01/24/2023] [Accepted: 12/01/2022] [Indexed: 01/12/2023] Open
Abstract
Epstein-Barr virus (EBV) is a ubiquitous human pathogen that is transmitted in saliva. EBV transits through the oral epithelium to infect B cells, where it establishes a life-long latent infection. Reinfection of the epithelium is believed to be mediated by virus shed from B cells, but whether a latent reservoir can exist in the epithelia is unknown. We previously developed an in vitro organotypic model of stratified epithelium where EBV can readily replicate within the suprabasal layers of the epithelium following apical infection mediated by virus-producing B cells. Given that infected epithelial cells and cell-free virus are observed in saliva, we examined the ability of both of these to mediate infection in organotypic cultures. Epithelial-derived cell-free virus was able to infect organotypic cultures from the apical surface, but showed enhanced infection of B cells. Conversely, B cell-derived virus exhibited enhanced infection of epithelial cells. While EBV has been detected in basal cells in oral hairy leukoplakia, it is unknown whether EBV can be seen in undifferentiated primary keratinocytes in the basal layer. Undifferentiated epithelial cells expressed proposed EBV receptors in monolayer and were susceptible to viral binding and entry. Integrins, and occasionally ephrin A2, were expressed in the basal layer of gingiva and tonsil derived organotypic cultures, but the known B-cell receptors HLAII and CD21 were not detected. Following infection with cell-free virus or virus-producing B cells at either the apical or basolateral surface of preformed organotypic cultures, abundant infection was detected in differentiated suprabasal cells while more limited but readily detectable infection was observed in the undifferentiated basal cells. Together, our data has provided new insight into EBV infection in stratified epithelium.
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Affiliation(s)
- Ian R. Hayman
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, United States of America
| | - Rachel M. Temple
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, United States of America
| | - Cole K. Burgess
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, United States of America
| | - Mary Ferguson
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, United States of America
| | - Jason Liao
- Department of Public Health Sciences, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, United States of America
- The Penn State Cancer Institute, Hershey, Pennsylvania, United States of America
| | - Craig Meyers
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, United States of America
- The Penn State Cancer Institute, Hershey, Pennsylvania, United States of America
| | - Clare E. Sample
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania, United States of America
- The Penn State Cancer Institute, Hershey, Pennsylvania, United States of America
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12
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Concomitant Inhibition of IRE1α/XBP1 Axis of UPR and PARP: A Promising Therapeutic Approach against c-Myc and Gammaherpesvirus-Driven B-Cell Lymphomas. Int J Mol Sci 2022; 23:ijms23169113. [PMID: 36012375 PMCID: PMC9409055 DOI: 10.3390/ijms23169113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 08/09/2022] [Accepted: 08/12/2022] [Indexed: 11/17/2022] Open
Abstract
It is emerging that targeting the adaptive functions of Unfolded Protein Response (UPR) may represent a promising anti-cancer therapeutic approach. This is particularly relevant for B-cell lymphomas, characterized by a high level of constitutive stress due to high c-Myc expression. In this study, we found that IRE1α/XBP1 axis inhibition exerted a stronger cytotoxic effect compared to the inhibition of the other two UPR sensors, namely PERK and ATF6, in Burkitt lymphoma (BL) cells, in correlation with c-Myc downregulation. Interestingly, such an effect was more evident in Epstein-Barr virus (EBV)-negative BL cells or those cells expressing type I latency compared to type III latency BL cells. The other interesting finding of this study was that the inhibition of IRE1α/XBP1 downregulated BRCA-1 and RAD51 and potentiated the cytotoxicity of PARP inhibitor AZD2661 against BL cells and also against Primary Effusion Lymphoma (PEL), another aggressive B-cell lymphoma driven by c-Myc and associated with gammaherpesvirus infection. These results suggest that combining the inhibition of UPR sensors, particularly IRE1α/XBP1 axis, and molecules involved in DDR, such as PARP, could offer a new therapeutic opportunity for treating aggressive B-cell lymphomas such as BL and PEL.
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13
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Reduced IRF4 expression promotes lytic phenotype in Type 2 EBV-infected B cells. PLoS Pathog 2022; 18:e1010453. [PMID: 35472072 PMCID: PMC9041801 DOI: 10.1371/journal.ppat.1010453] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 03/17/2022] [Indexed: 01/27/2023] Open
Abstract
Humans are infected with two types of EBV (Type 1 (T1) and Type 2 (T2)) that differ substantially in their EBNA2 and EBNA 3A/B/C latency proteins and have different phenotypes in B cells. T1 EBV transforms B cells more efficiently than T2 EBV in vitro, and T2 EBV-infected B cells are more lytic. We previously showed that both increased NFATc1/c2 activity, and an NFAT-binding motif within the BZLF1 immediate-early promoter variant (Zp-V3) contained in all T2 strains, contribute to lytic infection in T2 EBV-infected B cells. Here we compare cellular and viral gene expression in early-passage lymphoblastoid cell lines (LCLs) infected with either T1 or T2 EBV strains. Using bulk RNA-seq, we show that T2 LCLs are readily distinguishable from T1 LCLs, with approximately 600 differentially expressed cellular genes. Gene Set Enrichment Analysis (GSEA) suggests that T2 LCLs have increased B-cell receptor (BCR) signaling, NFAT activation, and enhanced expression of epithelial-mesenchymal-transition-associated genes. T2 LCLs also have decreased RNA and protein expression of a cellular gene required for survival of T1 LCLs, IRF4. In addition to its essential role in plasma cell differentiation, IRF4 decreases BCR signaling. Knock-down of IRF4 in a T1 LCL (infected with the Zp-V3-containing Akata strain) induced lytic reactivation whereas over-expression of IRF4 in Burkitt lymphoma cells inhibited both NFATc1 and NFATc2 expression and lytic EBV reactivation. Single-cell RNA-seq confirmed that T2 LCLs have many more lytic cells compared to T1 LCLs and showed that lytically infected cells have both increased NFATc1, and decreased IRF4, compared to latently infected cells. These studies reveal numerous differences in cellular gene expression in B cells infected with T1 versus T2 EBV and suggest that decreased IRF4 contributes to both the latent and lytic phenotypes in cells with T2 EBV.
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14
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The Epstein-Barr Virus Lytic Protein BMLF1 Induces Upregulation of GRP78 Expression through ATF6 Activation. Int J Mol Sci 2021; 22:ijms22084024. [PMID: 33919712 PMCID: PMC8070695 DOI: 10.3390/ijms22084024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 04/10/2021] [Accepted: 04/12/2021] [Indexed: 11/17/2022] Open
Abstract
The unfolded protein response (UPR) is an intracellular signaling pathway essential for alleviating the endoplasmic reticulum (ER) stress. To support the productive infection, many viruses are known to use different strategies to manipulate the UPR signaling network. However, it remains largely unclear whether the UPR signaling pathways are modulated in the lytic cycle of Epstein-Barr virus (EBV), a widely distributed human pathogen. Herein, we show that the expression of GRP78, a central UPR regulator, is up-regulated during the EBV lytic cycle. Our data further revealed that knockdown of GRP78 in EBV-infected cell lines did not substantially affect lytic gene expression; however, GRP78 knockdown in these cells markedly reduced the production of virus particles. Importantly, we identified that the early lytic protein BMLF1 is the key regulator critically contributing to the activation of the grp78 gene promoter. Mechanistically, we found that BMLF1 can trigger the proteolytic cleavage and activation of the UPR senor ATF6, which then transcriptionally activates the grp78 promoter through the ER stress response elements. Our findings therefore provide evidence for the connection between the EBV lytic cycle and the UPR, and implicate that the BMLF1-mediated ATF6 activation may play critical roles in EBV lytic replication.
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15
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Zhang F, Chen L, Zhou Y, Ding D, Hu Q, Liu Y, Li K, Wu S, He L, Lei M, Du R. Dexamethasone prevents the Epstein-Barr virus induced epithelial-mesenchymal transition in A549 cells. J Med Virol 2020; 92:3697-3708. [PMID: 32396272 DOI: 10.1002/jmv.25999] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 05/10/2020] [Indexed: 01/16/2023]
Abstract
Clinical data have shown that pulmonary interstitial fibrosis is likely to occur in the later stages of viral pneumonia. While viral infections are thought to cause chronic pulmonary interstitial inflammation and pulmonary fibrosis, it remains unclear if they promote pulmonary fibrosis by epithelial-mesenchymal transition (EMT). In this study, human epithelial cell line A549 has been used to model the infection of the Epstein-Barr virus (EBV) and the respiratory syncytial virus (RSV). Their differences were compared and the possible infection mechanisms analyzed by randomly assigning cells to one of five treatments. Exposure of the LMP1 is thought to be the key gene during EBV-induced EMT in the A549 cells. Enzyme-linked immunosorbent assay analysis revealed that the EBV infection was associated with the induction of a number of cytokines (interleukin-8 [IL-8], IL-13, tumor necrosis factor-α, and transforming growth factor-β) and dexamethasone (DXM) could significantly prevent the phenotypic changes, and partly the mechanisms related with the IL-13 pathway. Surprisingly, different results were seen with the RSV infection as the A549 cells still displayed an epithelial morphology but the levels of E-cadherin, α-SMA, vimentin, and fibronectin did not change. This is the first study demonstrating the different reactions induced by different viruses, and the protective effects of DXM on the EBV-induced EMT in the A549 cells by partially inhibiting the IL-13 pathway. These findings suggest a novel mechanism, by which DXM or anti-IL-13 may delay the progression of pulmonary fibrosis by preventing the progress of EBV-induced EMT.
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Affiliation(s)
- Fengqin Zhang
- Department of Respiratory and Critical Care Medicine, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Lei Chen
- Department of Respiratory and Critical Care Medicine, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ying Zhou
- Department of Respiratory and Critical Care Medicine, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Dan Ding
- Department of Respiratory and Critical Care Medicine, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qiongjie Hu
- Department of Radiology, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yiwen Liu
- Department of Radiology, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Kaiyan Li
- Department of Radiology, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Sisi Wu
- Department of Critical Medicine, Wuhan Central Hospital, Wuhan, China
| | - Li He
- Department of Respiratory and Critical Care Medicine, Jingzhou Central Hospital, The Second Clinical Medical College, Yangtze University, Jingzhou, China
| | - Mei Lei
- Department of Respiratory and Critical Care Medicine, Pulmonary Hospital, Wuhan, China
| | - Ronghui Du
- Department of Respiratory and Critical Care Medicine, Pulmonary Hospital, Wuhan, China
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16
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Epstein-Barr Virus Exploits the Secretory Pathway to Release Virions. Microorganisms 2020; 8:microorganisms8050729. [PMID: 32414202 PMCID: PMC7285239 DOI: 10.3390/microorganisms8050729] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 05/11/2020] [Accepted: 05/12/2020] [Indexed: 01/06/2023] Open
Abstract
Herpesvirus egress mechanisms are strongly associated with intracellular compartment remodeling processes. Previously, we and other groups have described that intracellular compartments derived from the Golgi apparatus are the maturation sites of Epstein-Barr virus (EBV) virions. However, the mechanism by which these virions are released from the host cell to the extracellular milieu is poorly understood. Here, I adapted two independent induction systems of the EBV lytic cycle in vitro, in the context of Rab GTPase silencing, to characterize the EBV release pathway. Immunofluorescence staining revealed that p350/220, the major EBV glycoprotein, partially co-localized with three Rab GTPases: Rab8a, Rab10, and Rab11a. Furthermore, the knockdown of these Rab GTPases promoted the intracellular accumulation of viral structural proteins by inhibiting its distribution to the plasma membrane. Finally, the knockdown of the Rab8a, Rab10, and Rab11a proteins suppressed the release of EBV infectious virions. Taken together, these findings support the hypothesis that mature EBV virions are released from infected cells to the extracellular milieu via the secretory pathway, as well as providing new insights into the EBV life cycle.
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17
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Buschle A, Hammerschmidt W. Epigenetic lifestyle of Epstein-Barr virus. Semin Immunopathol 2020; 42:131-142. [PMID: 32232535 PMCID: PMC7174264 DOI: 10.1007/s00281-020-00792-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 02/14/2020] [Indexed: 12/13/2022]
Abstract
Epstein-Barr virus (EBV) is a model of herpesvirus latency and epigenetic changes. The virus preferentially infects human B-lymphocytes (and also other cell types) but does not turn them straight into virus factories. Instead, it establishes a strictly latent infection in them and concomitantly induces the activation and proliferation of infected B cells. How the virus establishes latency in its target cells is only partially understood, but its latent state has been studied intensively by many. During latency, several copies of the viral genome are maintained as minichromosomes in the nucleus. In latently infected cells, most viral genes are epigenetically repressed by cellular chromatin constituents and DNA methylation, but certain EBV genes are spared and remain expressed to support the latent state of the virus in its host cell. Latency is not a dead end, but the virus can escape from this state and reactivate. Reactivation is a coordinated process that requires the removal of repressive chromatin components and a gain in accessibility for viral and cellular factors and machines to support the entire transcriptional program of EBV's ensuing lytic phase. We have a detailed picture of the initiating events of EBV's lytic phase, which are orchestrated by a single viral protein - BZLF1. Its induced expression can lead to the expression of all lytic viral proteins, but initially it fosters the non-licensed amplification of viral DNA that is incorporated into preformed capsids. In the virions, the viral DNA is free of histones and lacks methylated cytosine residues which are lost during lytic DNA amplification. This review provides an overview of EBV's dynamic epigenetic changes, which are an integral part of its ingenious lifestyle in human host cells.
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Affiliation(s)
- Alexander Buschle
- Research Unit Gene Vectors, Helmholtz Zentrum München, German Research Center for Environmental Health and German Centre for Infection Research (DZIF), Partner site Munich, Marchioninistr. 25, D-81377, Munich, Germany
| | - Wolfgang Hammerschmidt
- Research Unit Gene Vectors, Helmholtz Zentrum München, German Research Center for Environmental Health and German Centre for Infection Research (DZIF), Partner site Munich, Marchioninistr. 25, D-81377, Munich, Germany.
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18
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B Cell-Specific Transcription Activator PAX5 Recruits p300 To Support EBNA1-Driven Transcription. J Virol 2020; 94:JVI.02028-19. [PMID: 31941781 DOI: 10.1128/jvi.02028-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Accepted: 12/23/2019] [Indexed: 01/09/2023] Open
Abstract
The binding of Epstein-Barr Virus (EBV) nuclear antigen 1 (EBNA1) to the latent replication origin (oriP) triggers multiple downstream events to support virus-induced pathogenesis and tumorigenesis. Although EBV is widely recognized as a B-lymphotropic infectious agent, little is known about how tissue-specific factors are involved in the establishment of latency. Here, we showed that EBNA1 binds B cell activator PAX5 to promote EBNA1/oriP-dependent binding and transcription. In addition to showing that short hairpin RNA (shRNA)-mediated PAX5 knockdown substantially abrogated the above EBNA1-dependent functions, two mini-EBV reporter plasmids were used to perform nonlytic nano-luciferase (nLuc) activity and chromatin immunoprecipitation (ChIP) assays to show how EBNA1 cooperates with PAX5 to activate the transcription at the oriP site. The expression plasmids of two PAX5 mutants, V26G (EBNA1 binding mutant) and P80R (which remained EBNA1 associated), were used to assess their capability to restore the defects caused by PAX5 depletion in EBNA1/oriP-mediated binding, transcription, and maintenance of the genome copy number of the mini-EBV episome reporter in BJAB cells stably expressing EBNA1 or that of the EBV genome in EBV-infected BJAB cells. Since p300 is known to be associated with PAX5, we showed that the loss of function of the P80R mutant in support of EBNA1/oriP-mediated transcription under PAX5 depletion conditions was linked to its defective binding to p300. ChIP-quantitative PCR (qPCR) confirmed that P80R indeed failed to recruit p300 to the oriP DNA. Our discovery suggests that EBV has evolved an exquisite strategy to take advantage of tissue-specific factors to enable the establishment of viral latency.IMPORTANCE Although B cells are known to be the primary target for EBV infection, there is limited knowledge regarding the mechanism that determines this preferable tissue tropism. An in-depth understanding of the potential link of tissue-specific factors with the viral genes and their functioning is key to deciphering how EBV induces persistent infection in the distinct types of host cells. In this study, a substantial protein-protein interaction mediated by the B cell-specific activator PAX5 and EBNA1 was identified as the general requirement for the binding of EBNA1 to the latent replication origin and for downstream events. Of importance, the EBNA1-PAX5-p300 network is directly linked to EBNA1-dependent transcription. These findings suggest that targeting the viral gene-associated tissue-specific factors may lead to new therapeutic strategies for EBV-associated malignancies.
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19
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Huang HH, Wang WH, Feng TH, Chang LK. Rta is an Epstein-Barr virus tegument protein that improves the stability of capsid protein BORF1. Biochem Biophys Res Commun 2020; 523:773-779. [PMID: 31948747 DOI: 10.1016/j.bbrc.2020.01.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 01/05/2020] [Indexed: 11/30/2022]
Abstract
Rta, a key transcription factor expressed by Epstein-Barr virus (EBV), primarily acts to induce activation of the EBV lytic cycle. Interestingly, we observed from an immunogold assay that Rta is also present on the EBV capsid in the host cell nucleus, and a centrifugation study further revealed that Rta cofractionates with EBV virions. Importantly, cofractionated Rta showed similar properties as the EBV tegument protein, BGLF4. Glutathione S-transferase (GST)-pulldown and coimmunoprecipitation assays subsequently demonstrated that Rta directly interacts with the EBV capsid protein, BORF1. Rta was observed to colocalize with BORF1 in the nucleus during EBV lytic induction, and this interaction appears to influence BORF1 stability. Moreover, we found that BORF1 is modified by ubiquitin, and Rta reduces this ubiquitination. These results indicate that Rta may act as an inner tegument protein to improve EBV capsid stability and critical to viral infection.
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Affiliation(s)
- Hsiang-Hung Huang
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, Taipei, Taiwan
| | - Wen-Hung Wang
- Division of Infectious Disease, Department of Internal Medicine, Kaohsiung Medical University Chung-Ho Memorial Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan; Center for Tropical Medicine and Infectious Disease Research, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Tzu-Hui Feng
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, Taipei, Taiwan
| | - Li-Kwan Chang
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, Taipei, Taiwan.
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20
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Romero-Masters JC, Huebner SM, Ohashi M, Bristol JA, Benner BE, Barlow EA, Turk GL, Nelson SE, Baiu DC, Van Sciver N, Ranheim EA, Gumperz J, Sherer NM, Farrell PJ, Johannsen EC, Kenney SC. B cells infected with Type 2 Epstein-Barr virus (EBV) have increased NFATc1/NFATc2 activity and enhanced lytic gene expression in comparison to Type 1 EBV infection. PLoS Pathog 2020; 16:e1008365. [PMID: 32059024 PMCID: PMC7046292 DOI: 10.1371/journal.ppat.1008365] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 02/27/2020] [Accepted: 01/29/2020] [Indexed: 12/30/2022] Open
Abstract
Humans are infected with two distinct strains (Type 1 (T1) and Type 2 (T2)) of Epstein-Barr virus (EBV) that differ substantially in their EBNA2 and EBNA 3A/B/C latency genes and the ability to transform B cells in vitro. While most T1 EBV strains contain the "prototype" form of the BZLF1 immediate-early promoter ("Zp-P"), all T2 strains contain the "Zp-V3" variant, which contains an NFAT binding motif and is activated much more strongly by B-cell receptor signalling. Whether B cells infected with T2 EBV are more lytic than cells infected with T1 EBV is unknown. Here we show that B cells infected with T2 EBV strains (AG876 and BL5) have much more lytic protein expression compared to B cells infected with T1 EBV strains (M81, Akata, and Mutu) in both a cord blood-humanized (CBH) mouse model and EBV-transformed lymphoblastoid cell lines (LCLs). Although T2 LCLs grow more slowly than T1 LCLs, both EBV types induce B-cell lymphomas in CBH mice. T1 EBV strains (M81 and Akata) containing Zp-V3 are less lytic than T2 EBV strains, suggesting that Zp-V3 is not sufficient to confer a lytic phenotype. Instead, we find that T2 LCLs express much higher levels of activated NFATc1 and NFATc2, and that cyclosporine (an NFAT inhibitor) and knockdown of NFATc2 attenuate constitutive lytic infection in T2 LCLs. Both NFATc1 and NFATc2 induce lytic EBV gene expression when combined with activated CAMKIV (which is activated by calcium signaling and activates MEF2D) in Burkitt Akata cells. Together, these results suggest that B cells infected with T2 EBV are more lytic due to increased activity of the cellular NFATc1/c2 transcription factors in addition to the universal presence of the Zp-V3 form of BZLF1 promoter.
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Affiliation(s)
- James C. Romero-Masters
- Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Shane M. Huebner
- Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Makoto Ohashi
- Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Jillian A. Bristol
- Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Bayleigh E. Benner
- Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Elizabeth A. Barlow
- Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Gail L. Turk
- Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Scott E. Nelson
- Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Dana C. Baiu
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Nicholas Van Sciver
- Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Erik A. Ranheim
- Department of Pathology and Laboratory Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Jenny Gumperz
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Nathan M. Sherer
- Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Paul J. Farrell
- Section of Virology, Imperial College Faculty of Medicine, Norfolk Place, London, United Kingdom
| | - Eric C. Johannsen
- Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Shannon C. Kenney
- Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail:
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21
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Identifying the Cellular Interactome of Epstein-Barr Virus Lytic Regulator Zta Reveals Cellular Targets Contributing to Viral Replication. J Virol 2020; 94:JVI.00927-19. [PMID: 31694936 DOI: 10.1128/jvi.00927-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 10/30/2019] [Indexed: 02/06/2023] Open
Abstract
The human gammaherpesvirus Epstein-Barr virus (EBV) (human herpesvirus 4 [HHV4]) infects most adults and is an important contributor to the development of many types of lymphoid and epithelial cancers. Essential contributions of viral genes to viral replication are known, but the potential contributions of cell genes are less well delineated. A key player is the viral protein Zta (BZLF1, ZEBRA, or Z). This sequence-specific DNA-binding protein can disrupt EBV latency by driving the transcription of target genes and by interacting with the EBV lytic origin of replication. Here, we used an unbiased proteomics approach to identify the Zta-interactome in cells derived from Burkitt's lymphoma. Isolating Zta and associated proteins from Burkitt's lymphoma cells undergoing EBV replication, followed by tandem mass tag (TMT) mass spectrometry, resulted in the identification of 39 viral and cellular proteins within the Zta interactome. An association of Zta with the cellular protein NFATc2 was validated in independent experiments. Furthermore, the ability of Zta to attenuate the activity of an NFAT-dependent promoter was shown, which suggests a functional consequence for the association. The expression of Zta is itself regulated through NFAT activity, suggesting that Zta may contribute to a feedback loop that would limit its own expression, thus aiding viral replication by preventing the known toxic effects of Zta overexpression.IMPORTANCE Epstein-Barr virus infects most people across the world and causes several kinds of cancer. Zta is an important viral protein that makes the virus replicate by binding to its DNA and turning on the expression of some genes. We used a sensitive, unbiased approach to isolate and identify viral and cellular proteins that physically interact with Zta. This revealed 39 viral and cellular proteins. We found that one protein, termed NFATc2, was already known to be important for a very early step in viral replication. We identify that once this step has occurred, Zta reduces the effectiveness of NFATc2, and we suggest that this is important to prevent cells from dying before viral replication is complete and the mature virus is released from the cells.
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22
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Pharmacologic Activation of Lytic Epstein-Barr Virus Gene Expression without Virion Production. J Virol 2019; 93:JVI.00998-19. [PMID: 31341058 DOI: 10.1128/jvi.00998-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 07/18/2019] [Indexed: 12/14/2022] Open
Abstract
Several therapeutic strategies targeting Epstein-Barr virus (EBV)-associated tumors involve upregulation of viral lytic gene expression. Evidence has been presented that the unfolded protein response (UPR) leads to EBV lytic gene expression. Clofoctol, an antibacterial antibiotic, has been reported to upregulate the UPR in prostate cancer cell lines and to slow their growth. We investigated the effects of clofoctol on an EBV-positive Burkitt lymphoma cell line and confirmed the upregulation of all three branches of the UPR and activation of EBV lytic gene expression. While immediate early, early, and late EBV RNAs were all upregulated, immediate early and early viral proteins but not late viral proteins were expressed. Furthermore, infectious virions were not produced. The use of clofoctol in combination with a protein kinase R-like endoplasmic reticulum kinase inhibitor led to expression of late viral proteins. The effects of clofoctol on EBV lytic protein upregulation were not limited to lymphoid tumor cell lines but also occurred in naturally infected epithelial gastric cancer and nasopharyngeal cancer cell lines. An agent that upregulates lytic viral protein expression but that does not lead to the production of infectious virions may have particular value for lytic induction strategies in the clinical setting.IMPORTANCE Epstein-Barr virus is associated with many different cancers. In these cancers the viral genome is predominantly latent; i.e., most viral genes are not expressed, most viral proteins are not synthesized, and new virions are not produced. Some strategies for treating these cancers involve activation of lytic viral gene expression. We identify an antibacterial antibiotic, clofoctol, that is an activator of EBV lytic RNA and protein expression but that does not lead to virion production.
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23
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Efficient Epstein-Barr Virus Progeny Production Mediated by Cancer-Derived LMP1 and Virally-Encoded microRNAs. Microorganisms 2019; 7:microorganisms7050119. [PMID: 31052238 PMCID: PMC6560388 DOI: 10.3390/microorganisms7050119] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 04/25/2019] [Accepted: 04/28/2019] [Indexed: 12/22/2022] Open
Abstract
Epstein-Barr virus (EBV) genomes, particularly their latent genes, are heterogeneous among strains. The heterogeneity of EBV-encoded latent membrane protein 1 (LMP1) raises the question of whether there are functional differences between LMP1 expressed by cancer-associated EBV and that by non-cancerous strains. Here, we used bacterial artificial chromosome (BAC)-cloned EBV genomes retaining all virally encoded microRNA (miRNA) genes to investigate the functions of cancer-derived LMP1 in the context of the EBV genome. HEK293 cells were stably transfected with EBV-BAC clone DNAs encoding either nasopharyngeal carcinoma (NPC)-derived CAO-LMP1 (LMP1CAO) or LMP1 from a prototype B95-8 strain of EBV (LMP1B95-8). When an EBV-BAC clone DNA encoding LMP1CAO was stably transfected into HEK293 cells, it generated many more stable transformants than the control clone encoding LMP1B95-8. Furthermore, stably transfected HEK293 cells exhibited highly efficient production of progeny virus. Importantly, deletion of the clustered viral miRNA genes compromised the ability to produce progeny viruses. These results indicate that cancer-derived LMP1 and viral miRNAs together are necessary for efficient production of progeny virus, and that the resulting increase in efficiency contributes to EBV-mediated epithelial carcinogenesis.
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24
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Early Pattern of Epstein-Barr Virus Infection in Gastric Epithelial Cells by "Cell-in-cell". Virol Sin 2019; 34:253-261. [PMID: 30911896 DOI: 10.1007/s12250-019-00097-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 02/18/2019] [Indexed: 12/16/2022] Open
Abstract
Epstein-Barr virus (EBV) is an important human dsDNA virus, which has been shown to be associated with several malignancies including about 10% of gastric carcinomas. How EBV enters an epithelial cell has been an interesting project for investigation. "Cell-in-cell" infection was recently reported an efficient way for the entry of EBV into nasopharynx epithelial cells. The present approach was to explore the feasibility of this mode for EBV infection in gastric epithelial cells and the dynamic change of host inflammatory reaction. The EBV-positive lymphoblastic cells of Akata containing a GFP tag in the viral genome were co-cultured with the gastric epithelial cells (GES-1). The infection situation was observed under fluorescence and electron microscopies. Real-time quantitative PCR and Western-blotting assay were employed to detect the expression of a few specific cytokines and inflammatory factors. The results demonstrated that EBV could get into gastric epithelial cells by "cell-in-cell" infection but not fully successful due to the host fighting. IL-1β, IL-6 and IL-8 played prominent roles in the cellular response to the infection. The activation of NF-κB and HSP70 was also required for the host antiviral response. The results imply that the gastric epithelial cells could powerfully resist the virus invader via cell-in-cell at the early stage through inflammatory and innate immune responses.
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25
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Shen CL, Huang WH, Hsu HJ, Yang JH, Peng CW. GAP31 from an ancient medicinal plant exhibits anti-viral activity through targeting to Epstein-Barr virus nuclear antigen 1. Antiviral Res 2019; 164:123-130. [PMID: 30817940 DOI: 10.1016/j.antiviral.2019.02.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 01/12/2019] [Accepted: 02/22/2019] [Indexed: 11/19/2022]
Abstract
Since it was discovered as the first human tumor virus in 1964, Epstein-Barr Virus (EBV) is now implicated in several types of malignancies. Accordingly, certain aspects of EBV pathobiology have shown promise in anti-cancer research in developing virus-targeting methods for EBV-associated cancers. The unique role of EBV nuclear antigen 1 (EBNA1) in triggering episome-dependent functions has made it as the only latent gene to be expressed in most EBV+ neoplasms. Dimeric EBNA1 binds to the replication origin (oriP) to display its biological impact on EBV-driven cell transformation and maintenance. Hence, EBNA1/oriP has been made an ideal drug target site for anti-EBV protocol development. GAP31 protein was originally isolated from the seeds of an ancient medicinal plant Gelonium multiflorum. Although GAP31 has been shown to exhibit both anti-viral and anti-tumor activity, current understanding of the mechanistic picture underlying GAP31 functioning is not clear. Herein, we identify the EBNA1 DNA-binding domain as a core for GAP31 binding by performing affinity pulldown assays. Recombinant GAP31 (rGAP31) was shown to impair EBNA1-induced dimerization; consequently, it abrogated both EBNA1/oriP-mediated binding and transcription. Importantly, the therapeutic effects of GAP31 showed its capability to abrogate EBV-driven cell transformation and proliferation, and EBV-dependent tumorigenesis in xenograft animal models. Notably, the EBNA1 binding-mutant rGAP31R166A/R169A simply exhibits defective phenotypes in the above-mentioned studies. Our data suggest rGAP31 is a potential anti-viral drug which can be applied to the development of therapeutic strategies against EBV-related malignancies.
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Affiliation(s)
- Chih-Lung Shen
- Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan
| | - Wei-Han Huang
- Department of Oncology and Hematology, Buddhist Hualien Tzu Chi General Hospital, Hualien, Taiwan
| | - Hao-Jen Hsu
- Department of Life Sciences, Tzu Chi University, Hualien, 97004, Taiwan
| | - Jen-Hone Yang
- College of Medicine, Tzu Chi University, Department of Dermatology, Buddhist Hualien Tzu Chi General Hospital, Hualien, Taiwan
| | - Chih-Wen Peng
- Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan; Department of Life Sciences, Tzu Chi University, Hualien, 97004, Taiwan.
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26
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Majerciak V, Yang W, Zheng J, Zhu J, Zheng ZM. A Genome-Wide Epstein-Barr Virus Polyadenylation Map and Its Antisense RNA to EBNA. J Virol 2019; 93:e01593-18. [PMID: 30355690 PMCID: PMC6321932 DOI: 10.1128/jvi.01593-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 10/17/2018] [Indexed: 12/14/2022] Open
Abstract
Epstein-Barr virus (EBV) is a ubiquitous human pathogen associated with Burkitt's lymphoma and nasopharyngeal carcinoma. Although the EBV genome harbors more than a hundred genes, a full transcription map with EBV polyadenylation profiles remains unknown. To elucidate the 3' ends of all EBV transcripts genome-wide, we performed the first comprehensive analysis of viral polyadenylation sites (pA sites) using our previously reported polyadenylation sequencing (PA-seq) technology. We identified that EBV utilizes a total of 62 pA sites in JSC-1, 60 in Raji, and 53 in Akata cells for the expression of EBV genes from both plus and minus DNA strands; 42 of these pA sites are commonly used in all three cell lines. The majority of identified pA sites were mapped to the intergenic regions downstream of previously annotated EBV open reading frames (ORFs) and viral promoters. pA sites lacking an association with any known EBV genes were also identified, mostly for the minus DNA strand within the EBNA locus, a major locus responsible for maintenance of viral latency and cell transformation. The expression of these novel antisense transcripts to EBNA were verified by 3' rapid amplification of cDNA ends (RACE) and Northern blot analyses in several EBV-positive (EBV+) cell lines. In contrast to EBNA RNA expressed during latency, expression of EBNA-antisense transcripts, which is restricted in latent cells, can be significantly induced by viral lytic infection, suggesting potential regulation of viral gene expression by EBNA-antisense transcription during lytic EBV infection. Our data provide the first evidence that EBV has an unrecognized mechanism that regulates EBV reactivation from latency.IMPORTANCE Epstein-Barr virus represents an important human pathogen with an etiological role in the development of several cancers. By elucidation of a genome-wide polyadenylation landscape of EBV in JSC-1, Raji, and Akata cells, we have redefined the EBV transcriptome and mapped individual polymerase II (Pol II) transcripts of viral genes to each one of the mapped pA sites at single-nucleotide resolution as well as the depth of expression. By unveiling a new class of viral lytic RNA transcripts antisense to latent EBNAs, we provide a novel mechanism of how EBV might control the expression of viral latent genes and lytic infection. Thus, this report takes another step closer to understanding EBV gene structure and expression and paves a new path for antiviral approaches.
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Affiliation(s)
- Vladimir Majerciak
- Tumor Virus RNA Biology Section, RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland, USA
| | - Wenjing Yang
- Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Jing Zheng
- Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Jun Zhu
- Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Zhi-Ming Zheng
- Tumor Virus RNA Biology Section, RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland, USA
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27
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Hoji A, Xu S, Bilben H, Rowe DT. Calcium mobilization is responsible for Thapsigargin induced Epstein Barr virus lytic reactivation in in vitro immortalized lymphoblstoid cell lines. Heliyon 2018; 4:e00917. [PMID: 30480154 PMCID: PMC6240808 DOI: 10.1016/j.heliyon.2018.e00917] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 06/19/2018] [Accepted: 11/01/2018] [Indexed: 12/12/2022] Open
Abstract
The latent state is a critical component of all herpesvirus infections, and its regulation remains one of the most active areas of Epstein-Barr Virus (EBV) research. In particular, identifying environmental factors that trigger EBV reactivation into a virus-productive state has become a central goal in EBV latency research. Recently, a category of chemicals known as inducers of the endoplasmic reticulum unfolded protein response (UPR) have been shown to trigger EBV lytic reactivation in various established EBV-associated lymphoma cell lines. This has led to the recent belief that UPR is a universal cellular signaling pathway that directly triggers EBV lytic reactivation irrespective of cell type. We tested the potency of several widely used UPR inducers for EBV lytic reactivation on virus-immortalized primary lymphoblastoid cell lines (LCLs) in vitro. We found that, with the exception of Thapsigargin (Tg), UPR inducers did not trigger significant increases in BZLF1 transcripts or changes in the numbers of EBV genomic copies/cell in our panel of primary LCLs. Further investigation revealed that induction of lytic reactivation by Tg appeared to be due to its ability to trigger intracellular Ca2+ mobilization rather than its ability to induce UPR, based on our observations in which UPR induction alone was not sufficient to trigger the EBV lytic cycle in our LCLs. EBV immortalized LCLs have rarely been included in the majority of the lytic reactivation studies yet the characteristics of latent infection in LCLs should resemble those of proliferating B cells in clinically encountered lymphoproliferative diseases. Based on these observations, we propose an alternative mechanism of action for Tg in triggering EBV lytic reactivation in LCLs, and suggest that the proposed use of any chemical inducers of UPR for a purpose of oncolytic/lytic induction therapy needs to be fully evaluated pre-clinically in a panel of LCLs.
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Affiliation(s)
- Aki Hoji
- University of Pittsburgh, The Graduate School of Public Health, Department of Infectious Diseases and Microbiology, 130 Desoto St., Pittsburgh, PA, 15261, USA
| | - Susie Xu
- University of Pittsburgh, The Graduate School of Public Health, Department of Infectious Diseases and Microbiology, 130 Desoto St., Pittsburgh, PA, 15261, USA
| | - Holly Bilben
- University of Pittsburgh, The Graduate School of Public Health, Department of Infectious Diseases and Microbiology, 130 Desoto St., Pittsburgh, PA, 15261, USA
| | - David T Rowe
- University of Pittsburgh, The Graduate School of Public Health, Department of Infectious Diseases and Microbiology, 130 Desoto St., Pittsburgh, PA, 15261, USA
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28
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Mehta SK, Bloom DC, Plante I, Stowe R, Feiveson AH, Renner A, Dhummakupt A, Markan D, Zhang Y, Wu H, Scoles B, Cohen JI, Crucian B, Pierson DL. Reactivation of Latent Epstein-Barr Virus: A Comparison after Exposure to Gamma, Proton, Carbon, and Iron Radiation. Int J Mol Sci 2018; 19:ijms19102961. [PMID: 30274169 PMCID: PMC6213004 DOI: 10.3390/ijms19102961] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 09/23/2018] [Accepted: 09/26/2018] [Indexed: 01/17/2023] Open
Abstract
Among the many stressors astronauts are exposed to during spaceflight, cosmic radiation may lead to various serious health effects. Specifically, space radiation may contribute to decreased immunity, which has been documented in astronauts during short- and long-duration missions, as evidenced by several changes in cellular immunity and plasma cytokine levels. Reactivation of latent herpes viruses, either directly from radiation of latently infected cells and/or from perturbation of the immune system, may result in disease in astronauts. Epstein‒Barr virus (EBV) is one of the eight human herpes viruses known to infect more than 90% of human adults and persists for the life of the host without normally causing adverse effects. Reactivation of several latent viruses in astronauts is well documented, although the mechanism of reactivation is not well understood. We studied the effect of four different types of radiation, (1) 137Cs gamma rays, (2) 150-MeV protons, (3) 600 MeV/n carbon ions, and (4) 600 MeV/n iron ions on the activation of lytic gene transcription and of reactivation of EBV in a latently infected cell line (Akata) at doses of 0.1, 0.5, 1.0, and 2.0 Gy. The data showed that for all doses used in this study, lytic gene transcription was induced and median viral loads were significantly higher for all types of radiation than in corresponding control samples, with the increases detected as early as four days post-exposure and generally tapering off at later time points. The viability and size of EBV-infected Akata cells were highly variable and exhibited approximately the same trend in time for all radiation types at 0.1, 0.5, 1.0, and 2.0 Gy. This work shows that reactivation of viruses can occur due to the effect of different types of radiation on latently infected cells in the absence of changes or cytokines produced in the immune system. In general, gamma rays are more effective than protons, carbon ions, and iron ions in inducing latent virus reactivation, though these high-energy particles did induce more sustained and later reactivation of EBV lytic gene transcription. These findings also challenge the common relative biological effectiveness concept that is often used in radiobiology for other end points.
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Affiliation(s)
| | - David C Bloom
- Department of Molecular Genetics & Microbiology, University of Florida, Gainesville, FL 32610, USA.
| | - Ianik Plante
- KBRwyle, 2400 NASA Parkway, Houston, TX 77058, USA.
| | | | | | | | - Adit Dhummakupt
- Department of Molecular Genetics & Microbiology, University of Florida, Gainesville, FL 32610, USA.
| | - Dhruv Markan
- Albert Einstein Collège of Médicine, Bronx, NY 10461, USA.
| | - Ye Zhang
- NASA Kennedy Space Center, Cape Canaveral, FL 32899, USA.
| | - Honglu Wu
- NASA Johnson Space Center, Houston, TX 77058, USA.
| | - Blaire Scoles
- Department of Molecular Genetics & Microbiology, University of Florida, Gainesville, FL 32610, USA.
| | - Jeffrey I Cohen
- Laboratory of Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
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29
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Infection of Epstein⁻Barr Virus in Type III Latency Modulates Biogenesis of Exosomes and the Expression Profile of Exosomal miRNAs in the Burkitt Lymphoma Mutu Cell Lines. Cancers (Basel) 2018; 10:cancers10070237. [PMID: 30029522 PMCID: PMC6071279 DOI: 10.3390/cancers10070237] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 07/17/2018] [Indexed: 12/15/2022] Open
Abstract
Infection of Epstein–Barr virus (EBV), a ubiquitous human gamma herpesvirus, is associated with various malignancies in B lymphocytes and epithelial cells. EBV encodes 49 microRNAs in two separated regions, termed the BART and BHRF1 loci. Although accumulating evidence demonstrates that EBV infection regulates the profile of microRNAs in the cells, little is known about the microRNAs in exosomes released from infected cells. Here, we characterized the expression profile of intracellular and exosomal microRNAs in EBV-negative, and two related EBV-infected Burkitt lymphoma cell lines having type I and type III latency by next-generation sequencing. We found that the biogenesis of exosomes is upregulated in type III latently infected cells compared with EBV-negative and type I latently infected cells. We also observed that viral and several specific host microRNAs were predominantly incorporated in the exosomes released from the cells in type III latency. We confirmed that multiple viral microRNAs were transferred to the epithelial cells cocultured with EBV-infected B cells. Our findings indicate that EBV infection, in particular in type III latency, modulates the biogenesis of exosomes and the profile of exosomal microRNAs, potentially contributing to phenotypic changes in cells receiving these exosomes.
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30
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Nanbo A, Ohashi M, Yoshiyama H, Ohba Y. The Role of Transforming Growth Factor β in Cell-to-Cell Contact-Mediated Epstein-Barr Virus Transmission. Front Microbiol 2018; 9:984. [PMID: 29867885 PMCID: PMC5962739 DOI: 10.3389/fmicb.2018.00984] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 04/26/2018] [Indexed: 01/01/2023] Open
Abstract
Infection of Epstein–Barr virus (EBV), a ubiquitous human gamma herpesvirus, is closely linked to various lymphoid and epithelial malignancies. Previous studies demonstrated that the efficiency of EBV infection in epithelial cells is significantly enhanced by coculturing them with latently infected B cells relative to cell-free infection, suggesting that cell-to-cell contact-mediated viral transmission is the dominant mode of infection by EBV in epithelial cells. However, a detailed mechanism underlying this process has not been fully understood. In the present study, we assessed the role of transforming growth factor β (TGF-β), which is known to induce EBV's lytic cycle by upregulation of EBV's latent-lytic switch BZLF1 gene. We have found that 5 days of cocultivation facilitated cell-to-cell contact-mediated EBV transmission. Replication of EBV was induced in cocultured B cells both with and without a direct cell contact in a time-dependent manner. Treatment of a blocking antibody for TGF-β suppressed both induction of the lytic cycle in cocultured B cells and subsequent viral transmission. Cocultivation with epithelial cells facilitated expression of TGF-β receptors in B cells and increased their susceptibility to TGF-β. Finally, we confirmed the spontaneous secretion of TGF-β from epithelial cells, which was not affected by cell-contact. In contrast, the extracellular microvesicles, exosomes derived from cocultured cells partly contributed to cell-to-cell contact-mediated viral transmission. Taken together, our findings support a role for TGF-β derived from epithelial cells in efficient viral transmission, which fosters induction of the viral lytic cycle in the donor B cells.
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Affiliation(s)
- Asuka Nanbo
- Department of Cell Physiology, Faculty and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Makoto Ohashi
- Department of Oncology, University of Wisconsin, Madison, WI, United States
| | - Hironori Yoshiyama
- Department of Microbiology, Shimane University Faculty of Medicine, Izumo, Japan
| | - Yusuke Ohba
- Department of Cell Physiology, Faculty and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
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31
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Almohammed R, Osborn K, Ramasubramanyan S, Perez-Fernandez IBN, Godfrey A, Mancini EJ, Sinclair AJ. Mechanism of activation of the BNLF2a immune evasion gene of Epstein-Barr virus by Zta. J Gen Virol 2018; 99:805-817. [PMID: 29580369 PMCID: PMC6096924 DOI: 10.1099/jgv.0.001056] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The human gamma herpes virus Epstein–Barr virus (EBV) exploits multiple routes to evade the cellular immune response. During the EBV lytic replication cycle, viral proteins are expressed that provide excellent targets for recognition by cytotoxic T cells. This is countered by the viral BNLF2a gene. In B cells during latency, where BNLF2a is not expressed, we show that its regulatory region is embedded in repressive chromatin. The expression of BNLF2a mirrors the expression of a viral lytic cycle transcriptional regulator, Zta (BZLF1, EB1, ZEBRA), in B cells and we propose that Zta plays a role in up-regulating BNLF2a. In cells undergoing EBV lytic replication, we identified two distinct regions of interaction of Zta with the chromatin-associated BNLF2a promoter. We identify five potential Zta-response elements (ZREs) in the promoter that are highly conserved between virus isolates. Zta binds to these elements in vitro and activates the expression of the BNLF2a promoter in both epithelial and B cells. We also found redundancy amongst the ZREs. The EBV genome undergoes a biphasic DNA methylation cycle during its infection cycle. One of the ZREs contains an integral CpG motif. We show that this can be DNA methylated during EBV latency and that both Zta binding and promoter activation are enhanced by its methylation. In summary, we find that the BNLF2a promoter is directly targeted by Zta and that DNA methylation within the proximal ZRE aids activation. The implications for regulation of this key viral gene during the reactivation of EBV from latency are discussed.
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Affiliation(s)
- Rajaei Almohammed
- School of Life Sciences, University of Sussex, Brighton, East Sussex, UK.,Present address: Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Kay Osborn
- School of Life Sciences, University of Sussex, Brighton, East Sussex, UK
| | - Sharada Ramasubramanyan
- School of Life Sciences, University of Sussex, Brighton, East Sussex, UK.,Present address: RS Mehta Jain Department of Biochemistry and Cell Biology, Vision Research Foundation, Sankara Nethralaya, Chennai, India
| | | | - Anja Godfrey
- School of Life Sciences, University of Sussex, Brighton, East Sussex, UK
| | - Erika J Mancini
- School of Life Sciences, University of Sussex, Brighton, East Sussex, UK
| | - Alison J Sinclair
- School of Life Sciences, University of Sussex, Brighton, East Sussex, UK
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32
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Nanbo A, Noda T, Ohba Y. Epstein-Barr Virus Acquires Its Final Envelope on Intracellular Compartments With Golgi Markers. Front Microbiol 2018; 9:454. [PMID: 29615992 PMCID: PMC5864893 DOI: 10.3389/fmicb.2018.00454] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 02/27/2018] [Indexed: 01/18/2023] Open
Abstract
Herpesvirus subfamilies typically acquire their final envelope in various cytoplasmic compartments such as the trans-Golgi network (TGN), and endosomes prior to their secretion into the extracellular space. However, the sites for the final envelopment of Epstein–Barr virus (EBV), a ubiquitous human gamma herpesvirus, are poorly understood. Here, we characterized the sites for the final envelopment of EBV in Burkitt’s lymphoma cell lines induced into the lytic cycle by crosslinking cell surface IgG. Electron microscopy revealed the various stages of maturation and egress of progeny virions including mature EBV in irregular cytoplasmic vesicles. Immunofluorescence staining showed that gp350/220, the major EBV glycoprotein, and the viral capsid antigen, p18, efficiently colocalized with a cis-Golgi marker, GM130. gp350/220 partly colocalized with the TGN, which was distributed in a fragmented and dispersed pattern in the cells induced into the lytic cycle. In contrast, limited colocalization was observed between gp350/220 and endosomal markers, such as a multi-vesicular bodies marker, CD63, a recycling endosome marker, Rab11, and a regulatory secretion vesicles marker, Rab27a. Finally, we observed that treatment of cells with brefeldin A, an inhibitor of vesicle trafficking between the endoplasmic reticulum and Golgi apparatus, resulted in the perinuclear accumulation of gp350/220 and inhibition of its distribution to the plasma membrane. Brefeldin A also inhibited the release of infectious EBV. Taken together, our findings support a model in which EBV acquires its final envelope in intracellular compartments containing markers of Golgi apparatus, providing new insights into how EBV matures.
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Affiliation(s)
- Asuka Nanbo
- Department of Cell Physiology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Takeshi Noda
- Laboratory of Ultrastructural Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Yusuke Ohba
- Department of Cell Physiology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
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Kawada JI, Ando S, Torii Y, Watanabe T, Sato Y, Ito Y, Kimura H. Antitumor effects of duvelisib on Epstein-Barr virus-associated lymphoma cells. Cancer Med 2018. [PMID: 29522278 PMCID: PMC5911584 DOI: 10.1002/cam4.1311] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Epstein–Barr virus (EBV) is a ubiquitous oncogenic virus that is associated with B cell lymphomas, including Burkitt lymphoma and Hodgkin lymphoma. Previous studies have shown that the phosphatidylinositol 3‐kinase (PI3K)/Akt pathway is activated in EBV‐associated lymphomas and can be a novel therapeutic target. An oral dual inhibitor of PI3Kγ and PI3Kδ, duvelisib, is in clinical trials for the treatment of lymphoid malignancies. In this study, we evaluated how duvelisib affects the activity of the PI3K/Akt signaling pathway and if it has antitumor effects in EBV‐associated lymphoma cell lines. We found that the PI3K/Akt signaling pathway was activated in most of the B and T cell lymphoma cell lines tested. Additionally, duvelisib treatment inhibited cellular growth in the tested cell lines. Overall, B cell lines were more susceptible to duvelisib than T and NK cell lines in vitro regardless of EBV infection. However, the additional influence of duvelisib on the tumor microenvironment was not assessed. Duvelisib treatment induced both apoptosis and cell cycle arrest in EBV‐positive and ‐negative B cell lines, but not in T cell lines. Furthermore, duvelisib treatment reduced the expression of EBV lytic genes (BZLF1 and gp350/220) in EBV‐positive B cell lines, suggesting that duvelisib suppresses the lytic cycle of EBV induced by B cell receptor signaling. However, duvelisib did not induce a remarkable change in the expression of EBV latent genes. These results may indicate that there is therapeutic potential for duvelisib administration in the treatment of EBV‐associated B cell lymphomas and other B cell malignancies.
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Affiliation(s)
- Jun-Ichi Kawada
- Departments of Pediatrics, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Shotaro Ando
- Departments of Pediatrics, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Yuka Torii
- Departments of Pediatrics, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Takahiro Watanabe
- Departments of Virology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Yoshitaka Sato
- Departments of Virology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Yoshinori Ito
- Departments of Pediatrics, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
| | - Hiroshi Kimura
- Departments of Virology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
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Liu GT, Kung HN, Chen CK, Huang C, Wang YL, Yu CP, Lee CP. Improving nuclear envelope dynamics by EBV BFRF1 facilitates intranuclear component clearance through autophagy. FASEB J 2018; 32:3968-3983. [PMID: 29481305 DOI: 10.1096/fj.201701253r] [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] [Indexed: 01/13/2023]
Abstract
Although a vesicular nucleocytoplasmic transport system is believed to exist in eukaryotic cells, the features of this pathway are mostly unknown. Here, we report that the BFRF1 protein of the Epstein-Barr virus improves vesicular transport of nuclear envelope (NE) to facilitate the translocation and clearance of nuclear components. BFRF1 expression induces vesicles that selectively transport nuclear components to the cytoplasm. With the use of aggregation-prone proteins as tools, we found that aggregated nuclear proteins are dispersed when these BFRF1-induced vesicles are formed. BFRF1-containing vesicles engulf the NE-associated aggregates, exit through from the NE, and putatively fuse with autophagic vacuoles. Chemical treatment and genetic ablation of autophagy-related factors indicate that autophagosome formation and autophagy-linked FYVE protein-mediated autophagic proteolysis are involved in this selective clearance of nuclear proteins. Remarkably, vesicular transport, elicited by BFRF1, also attenuated nuclear aggregates accumulated in neuroblastoma cells. Accordingly, induction of NE-derived vesicles by BFRF1 facilitates nuclear protein translocation and clearance, suggesting that autophagy-coupled transport of nucleus-derived vesicles can be elicited for nuclear component catabolism in mammalian cells.-Liu, G.-T., Kung, H.-N., Chen, C.-K., Huang, C., Wang, Y.-L., Yu, C.-P., Lee, C.-P. Improving nuclear envelope dynamics by EBV BFRF1 facilitates intranuclear component clearance through autophagy.
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Affiliation(s)
- Guan-Ting Liu
- School of Nursing, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan
| | - Hsiu-Ni Kung
- Department of Anatomy and Cell Biology, College of Medicine, National Taiwan University, Taipei, Taiwan; and
| | - Chung-Kuan Chen
- School of Nursing, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan
| | - Cheng Huang
- Department of Biotechnology and Laboratory Science in Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Yung-Li Wang
- School of Nursing, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan
| | - Cheng-Pu Yu
- School of Nursing, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan
| | - Chung-Pei Lee
- School of Nursing, National Taipei University of Nursing and Health Sciences, Taipei, Taiwan
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Kato A, Imai K, Sato H, Ogata Y. Prevalence of Epstein-Barr virus DNA and Porphyromonas gingivalis in Japanese peri-implantitis patients. BMC Oral Health 2017; 17:148. [PMID: 29233156 PMCID: PMC5727789 DOI: 10.1186/s12903-017-0438-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Accepted: 11/24/2017] [Indexed: 11/22/2022] Open
Abstract
Background Peri-implantitis (PI) is an inflammatory reaction associated with functional deterioration of supporting bones around the dental implant. Recent studies suggested Epstein–Barr virus (EBV) is involved in the pathogenesis of periodontitis. We investigated the association between EBV and Porphyromonas gingivalis in Japanese PI patients. Methods Fifteen periodontally healthy individuals, 15 healthy implant patients and 15 PI patients were recruited. Forty five subgingival plaque samples were collected from the deepest probing pocket depth (PPD) site from each patient. Real-time PCR was used to detect EBV DNA and P. gingivalis. Results EBV and P. gingivalis were detected in 7 and 3 PPD sites of the healthy controls, in 9 and 4 PPD sites of the healthy implants, and in 13 and 14 PPD sites of the PI patients. P. gingivalis and coexistence of EBV and P. gingivalis were detected significantly higher in the PI patients than healthy controls and healthy implant patients. EBV was detected significantly higher in the PI patients than healthy controls. Conclusions Higher levels of EBV and P. gingivalis were detected in PPD sites of PI patients. These results suggest that coexistence of EBV and P. gingivalis may serve pathogenic factors cause for PI in Japanese dental patients.
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Affiliation(s)
- Ayako Kato
- Yorimasa Ogata, Department of Periodontology and Research Institute of Oral Science, Nihon University School of Dentistry at Matsudo, 2-870-1 Skakaecho-nishi, Matsudo, Chiba, 271-8587, Japan
| | - Kenichi Imai
- Department of Microbiology, Division of Immunology and Pathobiology, Dental Research Center, Nihon University School of Dentistry, Tokyo, 102-8310, Japan
| | - Hiroki Sato
- Yorimasa Ogata, Department of Periodontology and Research Institute of Oral Science, Nihon University School of Dentistry at Matsudo, 2-870-1 Skakaecho-nishi, Matsudo, Chiba, 271-8587, Japan
| | - Yorimasa Ogata
- Yorimasa Ogata, Department of Periodontology and Research Institute of Oral Science, Nihon University School of Dentistry at Matsudo, 2-870-1 Skakaecho-nishi, Matsudo, Chiba, 271-8587, Japan.
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Lv DW, Zhong J, Zhang K, Pandey A, Li R. Understanding Epstein-Barr Virus Life Cycle with Proteomics: A Temporal Analysis of Ubiquitination During Virus Reactivation. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2017; 21:27-37. [PMID: 28271981 DOI: 10.1089/omi.2016.0158] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Epstein-Barr virus (EBV) is a human γ-herpesvirus associated with cancer, including Burkitt lymphoma, nasopharyngeal, and gastric carcinoma. EBV reactivation in latently infected B cells is essential for persistent infection whereby B cell receptor (BCR) activation is a physiologically relevant stimulus. Yet, a global view of BCR activation-regulated protein ubiquitination is lacking when EBV is actively replicating. We report here, for the first time, the long-term effects of IgG cross-linking-regulated protein ubiquitination and offer a basis for dissecting the cellular environment during the course of EBV lytic replication. Using the Akata-BX1 (EBV+) and Akata-4E3 (EBV-) Burkitt lymphoma cells, we monitored the dynamic changes in protein ubiquitination using quantitative proteomics. We observed temporal alterations in the level of ubiquitination at ∼150 sites in both EBV+ and EBV- B cells post-IgG cross-linking, compared with controls with no cross-linking. The majority of protein ubiquitination was downregulated. The upregulated ubiquitination events were associated with proteins involved in RNA processing. Among the downregulated ubiquitination events were proteins involved in apoptosis, ubiquitination, and DNA repair. These comparative and quantitative proteomic observations represent the first analysis on the effects of IgG cross-linking at later time points when the majority of EBV genes are expressed and the viral genome is actively being replicated. In all, these data enhance our understanding of mechanistic linkages connecting protein ubiquitination, RNA processing, apoptosis, and the EBV life cycle.
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Affiliation(s)
- Dong-Wen Lv
- 1 Philips Institute for Oral Health Research, VCU School of Dentistry, Virginia Commonwealth University , Richmond, Virginia
| | - Jun Zhong
- 2 McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine , Baltimore, Maryland
| | - Kun Zhang
- 1 Philips Institute for Oral Health Research, VCU School of Dentistry, Virginia Commonwealth University , Richmond, Virginia
| | - Akhilesh Pandey
- 2 McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine , Baltimore, Maryland.,3 Institute of Bioinformatics , International Technology Park, Bangalore, India .,4 Diana Helis Henry Medical Research Foundation , New Orleans, Louisiana
| | - Renfeng Li
- 1 Philips Institute for Oral Health Research, VCU School of Dentistry, Virginia Commonwealth University , Richmond, Virginia.,5 Department of Microbiology and Immunology, School of Medicine, Virginia Commonwealth University , Richmond, Virginia.,6 Massey Cancer Center, Virginia Commonwealth University , Richmond, Virginia
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Goswami R, Shair KHY, Gershburg E. Molecular diversity of IgG responses to Epstein-Barr virus proteins in asymptomatic Epstein-Barr virus carriers. J Gen Virol 2017; 98:2343-2350. [PMID: 28795661 DOI: 10.1099/jgv.0.000891] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The Epstein-Barr virus (EBV) is a ubiquitous pathogen that infects over 90 % of adults. EBV is the primary etiological agent of infectious mononucleosis and is closely associated with nasopharyngeal carcinoma, gastric carcinoma, Hodgkin lymphoma and Burkitt lymphoma. Clinical serological assays for EBV diagnosis only survey a small portion of the viral proteome, which does not represent the total antigenic breadth presented to the immune system during viral infection. In this study, we have generated an expression library containing the majority of EBV ORFs, and have systematically evaluated IgG responses to those EBV proteins in sera from EBV carriers. In addition to confirming previously recognized dominant EBV antigens, this study has identified additional immunodominant antigens, and has revealed a more expansive antigenic profile of the humoral responses to EBV in asymptomatic carriers. This EBV expression library will be deposited in a public repository with the goal of disseminating this new research tool for the application of identifying potential new biomarkers for EBV-associated diseases.
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Affiliation(s)
- Ria Goswami
- Department of Medical Microbiology, Immunology, and Cell Biology, Southern Illinois University School of Medicine, Springfield, IL 62794-9626, USA.,Department of Internal Medicine, Southern Illinois University School of Medicine, Springfield, IL 62702, USA.,Present address: Duke Human Vaccine Institute, Duke University Medical Center, Durham, NC 27710, USA
| | - Kathy Ho Yen Shair
- Cancer Virology Program, University of Pittsburgh Cancer Institute Hillman Cancer Center, Pittsburgh, PA 15232, USA.,Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Edward Gershburg
- Department of Internal Medicine, Southern Illinois University School of Medicine, Springfield, IL 62702, USA.,Department of Medical Microbiology, Immunology, and Cell Biology, Southern Illinois University School of Medicine, Springfield, IL 62794-9626, USA.,Simmons Cancer Institute, Southern Illinois University School of Medicine, Springfield, IL 62702, USA
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38
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Drug Modulators of B Cell Signaling Pathways and Epstein-Barr Virus Lytic Activation. J Virol 2017; 91:JVI.00747-17. [PMID: 28566383 DOI: 10.1128/jvi.00747-17] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 05/24/2017] [Indexed: 11/20/2022] Open
Abstract
Epstein-Barr virus (EBV) is a ubiquitous human gammaherpesvirus that establishes a latency reservoir in B cells. In this work, we show that ibrutinib, idelalisib, and dasatinib, drugs that block B cell receptor (BCR) signaling and are used in the treatment of hematologic malignancies, block BCR-mediated lytic induction at clinically relevant doses. We confirm that the immunosuppressive drugs cyclosporine and tacrolimus also inhibit BCR-mediated lytic induction but find that rapamycin does not inhibit BCR-mediated lytic induction. Further investigation shows that mammalian target of rapamycin complex 2 (mTORC2) contributes to BCR-mediated lytic induction and that FK506-binding protein 12 (FKBP12) binding alone is not adequate to block activation. Finally, we show that BCR signaling can activate EBV lytic induction in freshly isolated B cells from peripheral blood mononuclear cells (PBMCs) and that activation can be inhibited by ibrutinib or idelalisib.IMPORTANCE EBV establishes viral latency in B cells. Activation of the B cell receptor pathway activates lytic viral expression in cell lines. Here we show that drugs that inhibit important kinases in the BCR signaling pathway inhibit activation of lytic viral expression but do not inhibit several other lytic activation pathways. Immunosuppressant drugs such as cyclosporine and tacrolimus but not rapamycin also inhibit BCR-mediated EBV activation. Finally, we show that BCR activation of lytic infection occurs not only in tumor cell lines but also in freshly isolated B cells from patients and that this activation can be blocked by BCR inhibitors.
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Djaoud Z, Guethlein LA, Horowitz A, Azzi T, Nemat-Gorgani N, Olive D, Nadal D, Norman PJ, Münz C, Parham P. Two alternate strategies for innate immunity to Epstein-Barr virus: One using NK cells and the other NK cells and γδ T cells. J Exp Med 2017; 214:1827-1841. [PMID: 28468758 PMCID: PMC5460997 DOI: 10.1084/jem.20161017] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2016] [Revised: 02/02/2017] [Accepted: 03/28/2017] [Indexed: 01/24/2023] Open
Abstract
Djaoud et al. show that Epstein–Barr virus infection triggers two types of human innate immune response, one mediated by the combination of NK cells and γδ T cells and the other committed to a strong NK cell response with little involvement of γδ T cells. Most humans become infected with Epstein–Barr virus (EBV), which then persists for life. Infrequently, EBV infection causes infectious mononucleosis (IM) or Burkitt lymphoma (BL). Type I EBV infection, particularly type I BL, stimulates strong responses of innate immune cells. Humans respond to EBV in two alternative ways. Of 24 individuals studied, 13 made strong NK and γδ T cell responses, whereas 11 made feeble γδ T cell responses but stronger NK cell responses. The difference does not correlate with sex, HLA type, or previous exposure to EBV or cytomegalovirus. Cohorts of EBV+ children and pediatric IM patients include both group 1 individuals, with high numbers of γδ T cells, and group 2 individuals, with low numbers. The even balance of groups 1 and 2 in the human population points to both forms of innate immune response to EBV having benefit for human survival. Correlating these distinctive responses with the progress of EBV infection might facilitate the management of EBV-mediated disease.
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Affiliation(s)
- Zakia Djaoud
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305 .,Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305
| | - Lisbeth A Guethlein
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305.,Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305
| | - Amir Horowitz
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305.,Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305
| | - Tarik Azzi
- Experimental Infectious Disease and Cancer Research, Children's Research Center, University Children's Hospital of Zurich, 8032 Zurich, Switzerland
| | - Neda Nemat-Gorgani
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305.,Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305
| | - Daniel Olive
- Team Immunity and Cancer, Centre de Recherche en Cancérologie de Marseille (CRCM), Institut National de la Santé et de la Recherche Médicale, U1068; Centre National de la Recherche Scientifique, UMR7258, Institut Paoli-Calmettes; Aix-Marseille University, UM 105, 13284 Marseille, France
| | - David Nadal
- Experimental Infectious Disease and Cancer Research, Children's Research Center, University Children's Hospital of Zurich, 8032 Zurich, Switzerland
| | - Paul J Norman
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305.,Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305
| | - Christian Münz
- Viral Immunobiology, Institute of Experimental Immunology, University of Zurich, 8006 Zurich, Switzerland
| | - Peter Parham
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305 .,Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305
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Lin R, Heeke D, Liu H, Rao E, Marshall JD, Chio V, Cataniag F, Yu L, Zuo F, McCarthy MP. Development of a robust, higher throughput green fluorescent protein (GFP)-based Epstein-Barr Virus (EBV) micro-neutralization assay. J Virol Methods 2017; 247:15-21. [PMID: 28457783 DOI: 10.1016/j.jviromet.2017.04.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 04/04/2017] [Accepted: 04/04/2017] [Indexed: 01/31/2023]
Abstract
The goal of most prophylactic vaccines is to elicit robust and effective neutralizing antibodies against the human pathogen target. The titer of neutralizing antibodies to Epstein-Barr Virus (EBV) is a useful biomarker for evaluating EBV vaccines. Here, the development and optimization of a 96-well micro-neutralization fluorescent imaging assay (FIA) using an EBV virus-encoding green fluorescent protein (GFP) to infect adherent EBV recipient cells is reported. The conditions were optimized for generating reproducible EBV-GFP virus, for maintaining viral infectivity for months, and for efficient viral infection of recipient cell culture. The utility of the EBV-GFP FIA neutralization assay was demonstrated in a mouse study of an investigational adjuvanted EBV gp350 subunit vaccine. This assay confirmed the generation of high titers of anti-EBV-neutralizing antibodies which correlated well with the established Raji cell-based flow cytometry-based EBV neutralization assay, as well as with anti-gp350 IgG titers. In naturally infected EBV+ human serum samples, a good correlation between anti-gp350 IgG ELISA titer and EBV-GFP FIA neutralization antibody titer was also observed. Taken together, these results demonstrate the establishment of a scalable high throughput EBV-GFP FIA micro-neutralization assay suitable to measure humoral EBV vaccine response in a large-scale human trial.
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Affiliation(s)
- Rui Lin
- Applied Immunology and Microbiology Group, MedImmune, Mountain View, CA, USA
| | - Darren Heeke
- Applied Immunology and Microbiology Group, MedImmune, Mountain View, CA, USA
| | - Hui Liu
- Applied Immunology and Microbiology Group, MedImmune, Mountain View, CA, USA
| | - Eileen Rao
- Translational Biology Group, MedImmune, Mountain View, CA, USA
| | | | - Vera Chio
- Applied Immunology and Microbiology Group, MedImmune, Mountain View, CA, USA
| | - Floro Cataniag
- Vaccine Platform Group, MedImmune, Gaithersburg, MD, USA
| | - Li Yu
- Statistical Sciences, MedImmune, Gaithersburg, MD, USA
| | - Fengrong Zuo
- Applied Immunology and Microbiology Group, MedImmune, Mountain View, CA, USA
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The SWI/SNF Chromatin Regulator BRG1 Modulates the Transcriptional Regulatory Activity of the Epstein-Barr Virus DNA Polymerase Processivity Factor BMRF1. J Virol 2017; 91:JVI.02114-16. [PMID: 28228591 DOI: 10.1128/jvi.02114-16] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 02/14/2017] [Indexed: 12/14/2022] Open
Abstract
During the lytic phase of Epstein-Barr virus (EBV), binding of the transactivator Zta to the origin of lytic replication (oriLyt) and the BHLF1 transcript, forming a stable RNA-DNA hybrid, is required to initiate viral DNA replication. EBV-encoded viral DNA replication proteins form complexes to amplify viral DNA. BMRF1, the viral DNA polymerase accessory factor, is essential for lytic DNA replication and also known as a transcriptional regulator of the expression of BHLF1 and BALF2 (single-stranded DNA [ssDNA]-binding protein). In order to determine systematically how BMRF1 regulates viral transcription, a BMRF1 knockout bacmid was generated to analyze viral gene expression using a viral DNA microarray. We found that a subset of Rta-responsive late genes, including BcLF1, BLLF1, BLLF2, and BDLF3, were downregulated in cells harboring a BMRF1 knockout EBV bacmid (p2089ΔBMRF1). In reporter assays, BMRF1 appears to transactivate a subset of viral late promoters through distinct pathways. BMRF1 activates the BDLF3 promoter in an SP1-dependent manner. Notably, BMRF1 associates with the transcriptional regulator BRG1 in EBV-reactivated cells. BMRF1-mediated transactivation activities on the BcLF1 and BLLF1 promoters were attenuated by knockdown of BRG1. In BRG1-depleted EBV-reactivated cells, BcLF1 and BLLF1 transcripts were reduced in number, resulting in reduced virion secretion. BMRF1 and BRG1 bound to the adjacent upstream regions of the BcLF1 and BLLF1 promoters, and depletion of BRG1 attenuated the recruitment of BMRF1 onto both promoters, suggesting that BRG1 is involved in BMRF1-mediated regulation of these two genes. Overall, we reveal a novel pathway by which BMRF1 can regulate viral promoters through interaction with BRG1.IMPORTANCE The cascade of viral gene expression during Epstein-Barr virus (EBV) replication is exquisitely regulated by the coordination of the viral DNA replication machinery and cellular factors. Upon lytic replication, the EBV immediate early proteins Zta and Rta turn on the expression of early proteins that assemble into viral DNA replication complexes. The DNA polymerase accessory factor, BMRF1, also is known to transactivate early gene expression through its interaction with SP1 or Zta on specific promoters. Through a global analysis, we demonstrate that BMRF1 also turns on a subset of Rta-regulated, late structural gene promoters. Searching for BMRF1-interacting cellular partners revealed that the SWI/SNF chromatin modifier BRG1 contributes to BMRF1-mediated transactivation of a subset of late promoters through protein-protein interaction and viral chromatin binding. Our findings indicate that BMRF1 regulates the expression of more viral genes than thought previously through distinct viral DNA replication-independent mechanisms.
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Nanbo A, Kachi K, Yoshiyama H, Ohba Y. Epstein–Barr virus exploits host endocytic machinery for cell-to-cell viral transmission rather than a virological synapse. J Gen Virol 2016; 97:2989-3006. [DOI: 10.1099/jgv.0.000605] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Asuka Nanbo
- Department of Cell Physiology, Hokkaido University Graduate School of Medicine, N15 W7, Kita-ku, Sapporo, Japan
| | - Kunihiro Kachi
- Graduate School of Pharmaceutical Sciences, Hokkaido University, N12 W6, Kita-ku, Sapporo, Japan
| | - Hironori Yoshiyama
- Department of Microbiology, Shimane University Faculty of Medicine, 89-1, Enya-cho, Izumo, Shimane, Japan
| | - Yusuke Ohba
- Department of Cell Physiology, Hokkaido University Graduate School of Medicine, N15 W7, Kita-ku, Sapporo, Japan
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Granato M, Rizzello C, Romeo MA, Yadav S, Santarelli R, D'Orazi G, Faggioni A, Cirone M. Concomitant reduction of c-Myc expression and PI3K/AKT/mTOR signaling by quercetin induces a strong cytotoxic effect against Burkitt's lymphoma. Int J Biochem Cell Biol 2016; 79:393-400. [PMID: 27620077 DOI: 10.1016/j.biocel.2016.09.006] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 09/01/2016] [Accepted: 09/09/2016] [Indexed: 11/28/2022]
Abstract
Burkitt's lymphoma is an aggressive B cell lymphoma whose pathogenesis involves mainly c-Myc translocation and hyperexpression, in addition to antigen-independent BCR signaling and, in some cases, EBV infection. As result of BCR signaling activation, the PI3K/AKT/mTOR pathway results constitutively activated also in the absence of EBV, promoting cell survival and counterbalancing the pro-apoptotic function that c-Myc may also exert. In this study we found that quercetin, a bioflavonoid widely distributed in plant kingdom, reduced c-Myc expression and inhibited the PI3K/AKT/mTOR activity in BL, leading to an apoptotic cell death. We observed a higher cytotoxic effect against the EBV-negative BL cells in comparison with the positive ones, suggesting that this oncogenic gammaherpesvirus confers an additional resistance to the quercetin treatment. Besides cell survival, PI3K/AKT/mTOR pathway also regulates autophagy: we found that quercetin induced a complete autophagic flux in BL cells, that contributes to c-Myc reduction in some of these cells. Indeed, autophagy inhibition by chloroquine partially restored c-Myc expression in EBV-positive (Akata) and EBV-negative (2A8) cells that harbor c-Myc mutation. Interestingly, chloroquine did not affect the quercetin-mediated reduction of c-Myc expression in Ramos cells, that have no c-Myc mutation in the coding region, although autophagy was induced. These results suggest that mutant c-Myc could be partially degraded through autophagy in BL cells, as previously reported for other mutant oncogenic proteins.
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Affiliation(s)
- Marisa Granato
- Department of Experimental Medicine, "Sapienza" University of Rome, Italy
| | - Celeste Rizzello
- Department of Experimental Medicine, "Sapienza" University of Rome, Italy
| | - Maria Anele Romeo
- Department of Experimental Medicine, "Sapienza" University of Rome, Italy
| | - Shivangi Yadav
- Department of Experimental Medicine, "Sapienza" University of Rome, Italy
| | - Roberta Santarelli
- Department of Experimental Medicine, "Sapienza" University of Rome, Italy
| | - Gabriella D'Orazi
- Translational Research Area, Regina Elena National Cancer Institute, Rome, Italy; Department of Medical, Oral and Biotechnological Sciences, University "G. d'Annunzio", Chieti, Italy
| | - Alberto Faggioni
- Department of Experimental Medicine, "Sapienza" University of Rome, Italy.
| | - Mara Cirone
- Department of Experimental Medicine, "Sapienza" University of Rome, Italy.
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44
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Shatzer A, Ali MA, Chavez M, Dowdell K, Lee MJ, Tomita Y, El-Hariry I, Trepel JB, Proia DA, Cohen JI. Ganetespib, an HSP90 inhibitor, kills Epstein-Barr virus (EBV)-infected B and T cells and reduces the percentage of EBV-infected cells in the blood. Leuk Lymphoma 2016; 58:923-931. [PMID: 27686857 DOI: 10.1080/10428194.2016.1213823] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
HSP90 inhibitors have been shown to kill Epstein-Barr virus (EBV)-infected cells by reducing the level of EBV EBNA-1 and/or LMP1. We treated virus-infected cells with ganetespib, an HSP90 inhibitor currently being evaluated in multiple clinical trials for cancer and found that the drug killed EBV-positive B and T cells and reduced the level of both EBV EBNA-1 and LMP1. Treatment of cells with ganetespib also reduced the level of pAkt. Ganetespib delayed the onset of EBV-positive lymphomas and prolonged survival in SCID mice inoculated with one EBV-transformed B-cell line, but not another B-cell line. The former cell line showed lower levels of EBNA-1 after treatment with ganetespib in vitro. Treatment of a patient with T-cell chronic active EBV with ganetespib reduced the percentage of EBV-positive cells in the peripheral blood. These data indicate that HSP90 inhibitors may have a role in the therapy of certain EBV-associated diseases.
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Affiliation(s)
- Amber Shatzer
- a Laboratory of Infectious Diseases , National Institute of Allergy and Infectious Diseases, National Institutes of Health , Bethesda , MD , USA
| | - Mir A Ali
- a Laboratory of Infectious Diseases , National Institute of Allergy and Infectious Diseases, National Institutes of Health , Bethesda , MD , USA
| | - Mayra Chavez
- a Laboratory of Infectious Diseases , National Institute of Allergy and Infectious Diseases, National Institutes of Health , Bethesda , MD , USA
| | - Kennichi Dowdell
- a Laboratory of Infectious Diseases , National Institute of Allergy and Infectious Diseases, National Institutes of Health , Bethesda , MD , USA
| | - Min-Jung Lee
- b Developmental Therapeutics Branch , National Cancer Institute, National Institutes of Health , Bethesda , MD , USA
| | - Yusuke Tomita
- b Developmental Therapeutics Branch , National Cancer Institute, National Institutes of Health , Bethesda , MD , USA
| | | | - Jane B Trepel
- b Developmental Therapeutics Branch , National Cancer Institute, National Institutes of Health , Bethesda , MD , USA
| | | | - Jeffrey I Cohen
- a Laboratory of Infectious Diseases , National Institute of Allergy and Infectious Diseases, National Institutes of Health , Bethesda , MD , USA
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45
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García JF, García JF, Maestre L, Lucas E, Sánchez-Verde L, Romero-Chala S, Piris MA, Roncador G. Genetic Immunization: A New Monoclonal Antibody for the Detection of BCL-6 Protein in Paraffin Sections. J Histochem Cytochem 2016; 54:31-8. [PMID: 16046671 DOI: 10.1369/jhc.5a6646.2005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Genetic immunization can be combined with hybridoma technology to generate high-affinity monoclonal antibodies (MAbs). A new anti-BCL-6 MAb (GI191E/A8) was produced by cloning full-length BCL-6 cDNA into a eukaryotic vector and delivering this into mouse epidermis using a helium gene gun. A comparative study was made of the specificity and the effects of formalin fixation on immunohistochemistry quality of GI191E/A8 and two other anti-BCL-6 MAbs. To evaluate its possible application to differential diagnosis of lymphomas, two tissue microarrays (89 diffuse large B-cell lymphomas and 24 B-cell chronic lymphocytic leukemia cases) were stained with GI191E/A8 and another anti-BCL-6 MAb produced by conventional means. Using GI191E/A8, the detection of BCL-6 protein was significantly increased, and its specificity was independent of formalin-fixation time. Using automatic quantified analysis, the correlation between the two anti-BCL-6 MAbs tested was identical in cases with overexpression or absence of BCL-6. In cases with intermediate BCL-6 protein expression, detection with GI191E/A8 was more sensitive. A significant association of higher BCL-6 expression and longer median overall survival times in diffuse large B-cell lymphomas was found. Using conventionally produced MAbs in the same patient group, the association was not significant.
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MESH Headings
- Animals
- Antibodies, Monoclonal
- Cell Line, Tumor
- DNA-Binding Proteins/immunology
- DNA-Binding Proteins/metabolism
- Diagnosis, Differential
- Fixatives
- Formaldehyde
- Humans
- Immunohistochemistry
- Leukemia, Lymphocytic, Chronic, B-Cell/diagnosis
- Leukemia, Lymphocytic, Chronic, B-Cell/metabolism
- Lymphoma, Non-Hodgkin/diagnosis
- Lymphoma, Non-Hodgkin/metabolism
- Mice
- Mice, Inbred BALB C
- Palatine Tonsil/metabolism
- Paraffin Embedding
- Proto-Oncogene Proteins c-bcl-6
- Survival Analysis
- Tissue Array Analysis
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Affiliation(s)
- José-Francisco García
- Monoclonal Antibodies Unit, Biotechnology Program, Centro Nacional de Investigaciones Oncológicas (Spanish National Cancer Centre), C/Melchor Fernández Almagro 3, E-28029 Madrid, Spain
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46
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Wu CC, Fang CY, Hsu HY, Chen YJ, Chou SP, Huang SY, Cheng YJ, Lin SF, Chang Y, Tsai CH, Chen JY. Luteolin inhibits Epstein-Barr virus lytic reactivation by repressing the promoter activities of immediate-early genes. Antiviral Res 2016; 132:99-110. [PMID: 27185626 DOI: 10.1016/j.antiviral.2016.05.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 04/27/2016] [Accepted: 05/09/2016] [Indexed: 02/08/2023]
Abstract
The lytic reactivation of Epstein-Barr virus (EBV) has been reported to be strongly associated with several human diseases, including nasopharyngeal carcinoma (NPC). Inhibition of the EBV lytic cycle has been shown to be of great benefit in the treatment of EBV-associated diseases. The administration of dietary compounds is safer and more convenient than other approaches to preventing EBV reactivation. We screened several dietary compounds for their ability to inhibit EBV reactivation in NPC cells. Among them, the flavonoid luteolin showed significant inhibition of EBV reactivation. Luteolin inhibited protein expression from EBV lytic genes in EBV-positive epithelial and B cell lines. It also reduced the numbers of EBV-reactivating cells detected by immunofluorescence analysis and reduced the production of virion. Furthermore, luteolin reduced the activities of the promoters of the immediate-early genes Zta (Zp) and Rta (Rp) and also inhibited Sp1-luc activity, suggesting that disruption of Sp1 binding is involved in the inhibitory mechanism. CHIP analysis revealed that luteolin suppressed the activities of Zp and Rp by deregulating Sp1 binding. Taken together, luteolin inhibits EBV reactivation by repressing the promoter activities of Zp and Rp, suggesting luteolin is a potential dietary compound for prevention of virus infection.
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Affiliation(s)
- Chung-Chun Wu
- National Institute of Cancer Research, National Health Research Institutes, Zhunan, Taiwan
| | - Chih-Yeu Fang
- National Institute of Cancer Research, National Health Research Institutes, Zhunan, Taiwan; Department of Pathology, Wan Fang Hospital, Taipei Medical University, Taipei, 116, Taiwan
| | - Hui-Yu Hsu
- National Institute of Cancer Research, National Health Research Institutes, Zhunan, Taiwan
| | - Yen-Ju Chen
- National Institute of Cancer Research, National Health Research Institutes, Zhunan, Taiwan
| | - Sheng-Ping Chou
- National Institute of Cancer Research, National Health Research Institutes, Zhunan, Taiwan
| | - Sheng-Yen Huang
- National Institute of Cancer Research, National Health Research Institutes, Zhunan, Taiwan
| | - Yu-Jhen Cheng
- National Institute of Cancer Research, National Health Research Institutes, Zhunan, Taiwan
| | - Su-Fang Lin
- National Institute of Cancer Research, National Health Research Institutes, Zhunan, Taiwan
| | - Yao Chang
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Tainan, Taiwan
| | - Ching-Hwa Tsai
- Department of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Jen-Yang Chen
- National Institute of Cancer Research, National Health Research Institutes, Zhunan, Taiwan; Department of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan.
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47
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Jha HC, Banerjee S, Robertson ES. The Role of Gammaherpesviruses in Cancer Pathogenesis. Pathogens 2016; 5:pathogens5010018. [PMID: 26861404 PMCID: PMC4810139 DOI: 10.3390/pathogens5010018] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 01/27/2016] [Indexed: 12/15/2022] Open
Abstract
Worldwide, one fifth of cancers in the population are associated with viral infections. Among them, gammaherpesvirus, specifically HHV4 (EBV) and HHV8 (KSHV), are two oncogenic viral agents associated with a large number of human malignancies. In this review, we summarize the current understanding of the molecular mechanisms related to EBV and KSHV infection and their ability to induce cellular transformation. We describe their strategies for manipulating major cellular systems through the utilization of cell cycle, apoptosis, immune modulation, epigenetic modification, and altered signal transduction pathways, including NF-kB, Notch, Wnt, MAPK, TLR, etc. We also discuss the important EBV latent antigens, namely EBNA1, EBNA2, EBNA3’s and LMP’s, which are important for targeting these major cellular pathways. KSHV infection progresses through the engagement of the activities of the major latent proteins LANA, v-FLIP and v-Cyclin, and the lytic replication and transcription activator (RTA). This review is a current, comprehensive approach that describes an in-depth understanding of gammaherpes viral encoded gene manipulation of the host system through targeting important biological processes in viral-associated cancers.
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Affiliation(s)
- Hem Chandra Jha
- Department of Microbiology and Tumor Virology Program, Abramson Comprehensive Cancer Center, Perelman School of Medicine at the University of Pennsylvania, 201E Johnson Pavilion, 3610, Hamilton Walk, Philadelphia, PA 19104, USA.
| | - Shuvomoy Banerjee
- Department of Microbiology and Tumor Virology Program, Abramson Comprehensive Cancer Center, Perelman School of Medicine at the University of Pennsylvania, 201E Johnson Pavilion, 3610, Hamilton Walk, Philadelphia, PA 19104, USA.
| | - Erle S Robertson
- Department of Microbiology and Tumor Virology Program, Abramson Comprehensive Cancer Center, Perelman School of Medicine at the University of Pennsylvania, 201E Johnson Pavilion, 3610, Hamilton Walk, Philadelphia, PA 19104, USA.
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48
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Harter MR, Liu CD, Shen CL, Gonzalez-Hurtado E, Zhang ZM, Xu M, Martinez E, Peng CW, Song J. BS69/ZMYND11 C-Terminal Domains Bind and Inhibit EBNA2. PLoS Pathog 2016; 12:e1005414. [PMID: 26845565 PMCID: PMC4742278 DOI: 10.1371/journal.ppat.1005414] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 01/04/2016] [Indexed: 12/20/2022] Open
Abstract
Epstein-Barr virus (EBV) nuclear antigen 2 (EBNA2) plays an important role in driving immortalization of EBV-infected B cells through regulating the expression of many viral and cellular genes. We report a structural study of the tumor suppressor BS69/ZMYND11 C-terminal region, comprised of tandem coiled-coil-MYND domains (BS69CC-MYND), in complex with an EBNA2 peptide containing a PXLXP motif. The coiled-coil domain of BS69 self-associates to bring two separate MYND domains in close proximity, thereby enhancing the BS69 MYND-EBNA2 interaction. ITC analysis of BS69CC-MYND with a C-terminal fragment of EBNA2 further suggests that the BS69CC-MYND homodimer synergistically binds to the two EBNA2 PXLXP motifs that are respectively located in the conserved regions CR7 and CR8. Furthermore, we showed that EBNA2 interacts with BS69 and down-regulates its expression at both mRNA and protein levels in EBV-infected B cells. Ectopic BS69CC-MYND is recruited to viral target promoters through interactions with EBNA2, inhibits EBNA2-mediated transcription activation, and impairs proliferation of lymphoblastoid cell lines (LCLs). Substitution of critical residues in the MYND domain impairs the BS69-EBNA2 interaction and abolishes the BS69 inhibition of the EBNA2-mediated transactivation and LCL proliferation. This study identifies the BS69 C-terminal domains as an inhibitor of EBNA2, which may have important implications in development of novel therapeutic strategies against EBV infection. Since the discovery of Epstein-Barr virus (EBV) 50 years ago, the etiologic links between EBV and a variety of human cancers have gained wide recognition. It is estimated that >90% of the worldwide population carry this virus, which causes over 200,000 cancers across the world every year. One of the key proteins in driving immortalization of EBV-infected B cells is Epstein-Barr virus nuclear antigen 2 (EBNA2), which regulates the expression of many cellular and viral genes. However, the molecular mechanism underlying the interactions between EBNA2 and cellular transcriptional regulators remains enigmatic. Here, we determined the crystal structure of the coiled-coil and MYND tandem domains of BS69/ZMYND11, a candidate tumor suppressor, in complex with an EBNA2 peptide containing a PXLXP motif. We found that the coiled-coil and MYND domains of BS69 cooperate in binding to EBNA2. We also showed that EBNA2 interacts with BS69 and down-regulates its expression at both mRNA and protein levels in EBV-associated B cells. Ectopic BS69 coiled-coil-MYND dual domain is recruited to viral target promoters through interaction with EBNA2, inhibits EBNA2-mediated transcription activation, and impairs proliferation of lymphoblastoid cell lines (LCLs). Together, this study identifies the BS69 C-terminal domains as an inhibitor of EBNA2.
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Affiliation(s)
- Matthew R. Harter
- Department of Biochemistry, University of California, Riverside, Riverside, California, United States of America
| | - Cheng-Der Liu
- Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan
| | - Chih-Lung Shen
- Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan
| | - Elsie Gonzalez-Hurtado
- Department of Biochemistry, University of California, Riverside, Riverside, California, United States of America
- MARC U-STAR Program, University of California, Riverside, Riverside, California, United States of America
| | - Zhi-Min Zhang
- Department of Biochemistry, University of California, Riverside, Riverside, California, United States of America
| | - Muyu Xu
- Department of Biochemistry, University of California, Riverside, Riverside, California, United States of America
| | - Ernest Martinez
- Department of Biochemistry, University of California, Riverside, Riverside, California, United States of America
- MARC U-STAR Program, University of California, Riverside, Riverside, California, United States of America
| | - Chih-Wen Peng
- Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan
- * E-mail: (CWP); (JS)
| | - Jikui Song
- Department of Biochemistry, University of California, Riverside, Riverside, California, United States of America
- * E-mail: (CWP); (JS)
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49
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Shi Y, Peng SL, Yang LF, Chen X, Tao YG, Cao Y. Co-infection of Epstein-Barr virus and human papillomavirus in human tumorigenesis. CHINESE JOURNAL OF CANCER 2016; 35:16. [PMID: 26801987 PMCID: PMC4724123 DOI: 10.1186/s40880-016-0079-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/22/2015] [Accepted: 08/07/2015] [Indexed: 12/17/2022]
Abstract
Viral infections contribute to approximately 12% of cancers worldwide, with the vast majority occurring in developing countries and areas. Two DNA viruses, Epstein-Barr virus (EBV) and human papillomavirus (HPV), are associated with 38% of all virus-associated cancers. The probability of one patient infected with these two distinct types of viruses is increasing. Here, we summarize the co-infection of EBV and HPV in human malignancies and address the possible mechanisms for the co-infection of EBV and HPV during tumorigenesis.
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Affiliation(s)
- Ying Shi
- Cancer Research Institute, Central South University, Changsha, 410078, Hunan, P. R. China.
- Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Changsha, 410078, Hunan, P. R. China.
- Key Laboratory of Carcinogenesis, National Health and Family Planning Commission, Changsha, 410078, Hunan, P. R. China.
| | - Song-Ling Peng
- Cancer Research Institute, Central South University, Changsha, 410078, Hunan, P. R. China.
- Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Changsha, 410078, Hunan, P. R. China.
- Key Laboratory of Carcinogenesis, National Health and Family Planning Commission, Changsha, 410078, Hunan, P. R. China.
| | - Li-Fang Yang
- Cancer Research Institute, Central South University, Changsha, 410078, Hunan, P. R. China.
- Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Changsha, 410078, Hunan, P. R. China.
- Key Laboratory of Carcinogenesis, National Health and Family Planning Commission, Changsha, 410078, Hunan, P. R. China.
| | - Xue Chen
- Cancer Research Institute, Central South University, Changsha, 410078, Hunan, P. R. China.
- Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Changsha, 410078, Hunan, P. R. China.
- Key Laboratory of Carcinogenesis, National Health and Family Planning Commission, Changsha, 410078, Hunan, P. R. China.
| | - Yong-Guang Tao
- Cancer Research Institute, Central South University, Changsha, 410078, Hunan, P. R. China.
- Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Changsha, 410078, Hunan, P. R. China.
- Key Laboratory of Carcinogenesis, National Health and Family Planning Commission, Changsha, 410078, Hunan, P. R. China.
| | - Ya Cao
- Cancer Research Institute, Central South University, Changsha, 410078, Hunan, P. R. China.
- Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Changsha, 410078, Hunan, P. R. China.
- Key Laboratory of Carcinogenesis, National Health and Family Planning Commission, Changsha, 410078, Hunan, P. R. China.
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50
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The translation inhibitor silvestrol exhibits direct anti-tumor activity while preserving innate and adaptive immunity against EBV-driven lymphoproliferative disease. Oncotarget 2015; 6:2693-708. [PMID: 25393910 PMCID: PMC4413611 DOI: 10.18632/oncotarget.2098] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 06/11/2014] [Indexed: 01/25/2023] Open
Abstract
Treatment options for patients with Epstein-Barr Virus-driven lymphoproliferative diseases (EBV-LPD) are limited. Chemo-immunotherapeutic approaches often lead to immune suppression, risk of lethal infection and EBV reactivation, thus it is essential to identify agents that can deliver direct anti-tumor activity while preserving innate and adaptive host immune surveillance. Silvestrol possesses direct anti-tumor activity in multiple hematologic malignancies while causing minimal toxicity to normal mononuclear cells. However, the effects of silvestrol on immune function have not been described. We utilized in vitro and in vivo models of EBV-LPD to simultaneously examine the impact of silvestrol on both tumor and normal immune function. We show that silvestrol induces direct anti-tumor activity against EBV-transformed lymphoblastoid cell lines (LCL), with growth inhibition, decreased expression of the EBV oncogene latent membrane protein-1, and inhibition of the downstream AKT, STAT1 and STAT3 signaling pathways. Silvestrol promoted potent indirect anti-tumor effects by preserving expansion of innate and EBV antigen-specific adaptive immune effector subsets capable of effective clearance of LCL tumor targets in autologous co-cultures. In an animal model of spontaneous EBV-LPD, silvestrol demonstrated significant therapeutic activity dependent on the presence of CD8-positive T-cells. These findings establish a novel immune-sparing activity of silvestrol, justifying further exploration in patients with EBV-positive malignancies.
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