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Lurain KA, Ramaswami R, Krug LT, Whitby D, Ziegelbauer JM, Wang HW, Yarchoan R. HIV-associated cancers and lymphoproliferative disorders caused by Kaposi sarcoma herpesvirus and Epstein-Barr virus. Clin Microbiol Rev 2024; 37:e0002223. [PMID: 38899877 PMCID: PMC11391709 DOI: 10.1128/cmr.00022-23] [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] [Indexed: 06/21/2024] Open
Abstract
SUMMARYWithin weeks of the first report of acquired immunodeficiency syndrome (AIDS) in 1981, it was observed that these patients often had Kaposi sarcoma (KS), a hitherto rarely seen skin tumor in the USA. It soon became apparent that AIDS was also associated with an increased incidence of high-grade lymphomas caused by Epstein-Barr virus (EBV). The association of AIDS with KS remained a mystery for more than a decade until Kaposi sarcoma-associated herpesvirus (KSHV) was discovered and found to be the cause of KS. KSHV was subsequently found to cause several other diseases associated with AIDS and human immunodeficiency virus (HIV) infection. People living with HIV/AIDS continue to have an increased incidence of certain cancers, and many of these cancers are caused by EBV and/or KSHV. In this review, we discuss the epidemiology, virology, pathogenesis, clinical manifestations, and treatment of cancers caused by EBV and KSHV in persons living with HIV.
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Affiliation(s)
- Kathryn A Lurain
- The HIV and AIDS Malignancy Branch, Center for Cancer Research, Bethesda, Maryland, USA
| | - Ramya Ramaswami
- The HIV and AIDS Malignancy Branch, Center for Cancer Research, Bethesda, Maryland, USA
| | - Laurie T Krug
- The HIV and AIDS Malignancy Branch, Center for Cancer Research, Bethesda, Maryland, USA
| | - Denise Whitby
- Viral Oncology Section, AIDS and Cancer Virus Program, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - Joseph M Ziegelbauer
- The HIV and AIDS Malignancy Branch, Center for Cancer Research, Bethesda, Maryland, USA
| | - Hao-Wei Wang
- Laboratory of Pathology, National Cancer Institute, Bethesda, Maryland, USA
| | - Robert Yarchoan
- The HIV and AIDS Malignancy Branch, Center for Cancer Research, Bethesda, Maryland, USA
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2
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Roberts BK, Collado G, Barnes BJ. Role of interferon regulatory factor 5 (IRF5) in tumor progression: Prognostic and therapeutic potential. Biochim Biophys Acta Rev Cancer 2024; 1879:189061. [PMID: 38141865 DOI: 10.1016/j.bbcan.2023.189061] [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: 11/09/2023] [Revised: 12/15/2023] [Accepted: 12/18/2023] [Indexed: 12/25/2023]
Abstract
Canonically, the transcription factor interferon regulatory factor 5 (IRF5) is a key mediator of innate and adaptive immunity downstream of pathogen recognition receptors such as Toll-like receptors (TLRs). Hence, dysregulation of IRF5 function has been widely implicated in inflammatory and autoimmune diseases. Over the last few decades, dysregulation of IRF5 expression has been also reported in hematologic malignancies and solid cancers that support a role for IRF5 in malignant transformation, tumor immune regulation, clinical prognosis, and treatment response. This review will provide an in-depth overview of the current literature regarding the mechanisms by which IRF5 functions as either a tumor suppressor or oncogene, its role in metastasis, regulation of the tumor-immune microenvironment, utility as a prognostic indicator of disease, and new developments in IRF5 therapeutics that may be used to remodel tumor immunity.
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Affiliation(s)
- Bailey K Roberts
- Center for Autoimmune Musculoskeletal and Hematopoietic Disease, The Feinstein Institutes for Medical Research, Manhasset, NY 11030, United States of America; Elmezzi Graduate School of Molecular Medicine, Northwell Health, Manhasset, NY 11030, United States of America
| | - Gilbert Collado
- Center for Autoimmune Musculoskeletal and Hematopoietic Disease, The Feinstein Institutes for Medical Research, Manhasset, NY 11030, United States of America
| | - Betsy J Barnes
- Center for Autoimmune Musculoskeletal and Hematopoietic Disease, The Feinstein Institutes for Medical Research, Manhasset, NY 11030, United States of America; Departments of Pediatrics and Molecular Medicine, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY 11549, United States of America.
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3
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Brune Z, Li D, Song S, Li DI, Castro I, Rasquinha R, Rice MR, Guo Q, Kampta K, Moss M, Lallo M, Pimenta E, Somerville C, Lapan M, Nelson V, Dos Santos CO, Blanc L, Pruitt K, Barnes BJ. Loss of IRF5 increases ribosome biogenesis leading to alterations in mammary gland architecture and metastasis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.01.538998. [PMID: 37292919 PMCID: PMC10246023 DOI: 10.1101/2023.05.01.538998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Despite the progress made in identifying cellular factors and mechanisms that predict progression and metastasis, breast cancer remains the second leading cause of death for women in the US. Using The Cancer Genome Atlas and mouse models of spontaneous and invasive mammary tumorigenesis, we identified that loss of function of interferon regulatory factor 5 (IRF5) is a predictor of metastasis and survival. Histologic analysis of Irf5 -/- mammary glands revealed expansion of luminal and myoepithelial cells, loss of organized glandular structure, and altered terminal end budding and migration. RNA-seq and ChIP-seq analyses of primary mammary epithelial cells from Irf5 +/+ and Irf5 -/- littermate mice revealed IRF5-mediated transcriptional regulation of proteins involved in ribosomal biogenesis. Using an invasive model of breast cancer lacking Irf5 , we demonstrate that IRF5 re-expression inhibits tumor growth and metastasis via increased trafficking of tumor infiltrating lymphocytes and altered tumor cell protein synthesis. These findings uncover a new function for IRF5 in the regulation of mammary tumorigenesis and metastasis. Highlights Loss of IRF5 is a predictor of metastasis and survival in breast cancer.IRF5 contributes to the regulation of ribosome biogenesis in mammary epithelial cells.Loss of IRF5 function in mammary epithelial cells leads to increased protein translation.
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Yanai H, Negishi H, Taniguchi T. The IRF family of transcription factors: Inception, impact and implications in oncogenesis. Oncoimmunology 2021; 1:1376-1386. [PMID: 23243601 PMCID: PMC3518510 DOI: 10.4161/onci.22475] [Citation(s) in RCA: 183] [Impact Index Per Article: 61.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Members of the interferon-regulatory factor (IRF) proteins family were originally identified as transcriptional regulators of the Type I interferon system. Thanks to consistent advances made in our understanding of the immunobiology of innate receptors, it is now clear that several IRFs are critical for the elicitation of innate pattern recognition receptors, and—as a consequence—for adaptive immunity. In addition, IRFs have attracted great attentions as they modulate cellular responses that are involved in tumorigenesis. The regulation of oncogenesis by IRFs has important implications for understanding the host susceptibility to several Types of cancers, their progression, as well as the potential for therapeutic interventions.
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Affiliation(s)
- Hideyuki Yanai
- Department of Molecular Immunology; Institute of Industrial Science; The University of Tokyo; Tokyo, Japan ; Core Research for Evolution Science and Technology; Japan Science and Technology Agency; Chiyoda-ku, Tokyo, Japan
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Choi YB, Cousins E, Nicholas J. Novel Functions and Virus-Host Interactions Implicated in Pathogenesis and Replication of Human Herpesvirus 8. Recent Results Cancer Res 2021; 217:245-301. [PMID: 33200369 DOI: 10.1007/978-3-030-57362-1_11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Human herpesvirus 8 (HHV-8) is classified as a γ2-herpesvirus and is related to Epstein-Barr virus (EBV), a γ1-herpesvirus. One important aspect of the γ-herpesviruses is their association with neoplasia, either naturally or in animal model systems. HHV-8 is associated with B-cell-derived primary effusion lymphoma (PEL) and multicentric Castleman's disease (MCD), endothelial-derived Kaposi's sarcoma (KS), and KSHV inflammatory cytokine syndrome (KICS). EBV is also associated with a number of B-cell malignancies, such as Burkitt's lymphoma, Hodgkin's lymphoma, and posttransplant lymphoproliferative disease, in addition to epithelial nasopharyngeal and gastric carcinomas. Despite the similarities between these viruses and their associated malignancies, the particular protein functions and activities involved in key aspects of virus biology and neoplastic transformation appear to be quite distinct. Indeed, HHV-8 specifies a number of proteins for which counterparts had not previously been identified in EBV, other herpesviruses, or even viruses in general, and these proteins are believed to play vital functions in virus biology and to be involved centrally in viral pathogenesis. Additionally, a set of microRNAs encoded by HHV-8 appears to modulate the expression of multiple host proteins to provide conditions conductive to virus persistence within the host and possibly contributing to HHV-8-induced neoplasia. Here, we review the molecular biology underlying these novel virus-host interactions and their potential roles in both virus biology and virus-associated disease.
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Affiliation(s)
- Young Bong Choi
- Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Department of Oncology, Johns Hopkins University School of Medicine, 1650 Orleans Street, Baltimore, MD, 21287, USA.
| | - Emily Cousins
- Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Department of Oncology, Johns Hopkins University School of Medicine, 1650 Orleans Street, Baltimore, MD, 21287, USA
| | - John Nicholas
- Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Department of Oncology, Johns Hopkins University School of Medicine, 1650 Orleans Street, Baltimore, MD, 21287, USA
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Kaposi's Sarcoma-Associated Herpesvirus Drives a Super-Enhancer-Mediated Survival Gene Expression Program in Primary Effusion Lymphoma. mBio 2020; 11:mBio.01457-20. [PMID: 32843547 PMCID: PMC7448273 DOI: 10.1128/mbio.01457-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) causes primary effusion lymphoma (PEL). The cellular transcription factor (TF) interferon (IFN) regulatory factor 4 (IRF4) is an essential oncogene in PEL, but its specific role in PEL and how KSHV deregulates IRF4 remain unknown. Here, we report that the KSHV latency protein viral interferon regulatory factor 3 (vIRF3) cooperates with IRF4 and cellular BATF (basic leucine zipper ATF-like TF) to drive a super-enhancer (SE)-mediated oncogenic transcriptional program in PEL. Chromatin immunoprecipitation coupled with next-generation sequencing (ChIP-Seq) experiments demonstrated that IRF4, vIRF3, and BATF cooccupy the SEs of key survival genes, in a pattern that is distinct from those seen with other IRF4-driven malignancies. All three proteins cooperatively drive SE-mediated IRF4 overexpression. Inactivation of vIRF3 and, to a lesser extent, BATF phenocopies the gene expression changes and loss of cellular viability observed upon inactivation of IRF4. In sum, this work suggests that KSHV vIRF3 and cellular IRF4 and BATF cooperate as oncogenic transcription factors on SEs to promote cellular survival and proliferation in KSHV-associated lymphomas.IMPORTANCE Kaposi's sarcoma-associated herpesvirus (KSHV) causes the aggressive disease primary effusion lymphoma (PEL). Here, we show that a viral transcription factor (vIRF3) cooperates with the cellular transcription factor IRF4 to control an oncogenic gene expression program in PEL cells. These proteins promote KSHV-mediated B cell transformation by activating the expression of prosurvival genes through super-enhancers. Our report thus demonstrates that this DNA tumor virus encodes a transcription factor that functions with cellular IRF4 to drive oncogenic transcriptional reprogramming.
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Xiang Q, Ju H, Nicholas J. USP7-Dependent Regulation of TRAF Activation and Signaling by a Viral Interferon Regulatory Factor Homologue. J Virol 2020; 94:e01553-19. [PMID: 31666375 PMCID: PMC6955280 DOI: 10.1128/jvi.01553-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 10/22/2019] [Indexed: 01/12/2023] Open
Abstract
Human herpesvirus 8 (HHV-8) encodes four viral interferon regulatory factors (vIRFs 1 to 4), all of which are expressed during lytic replication and inhibit a variety of antiviral signaling pathways. Viral IRFs 1, 2, and 3 are also expressed during latency in primary effusion lymphoma (PEL) cells, and vIRF-1 and vIRF-3 have been reported to promote PEL cell viability. Viral IRFs 1, 3, and 4 are known to interact with ubiquitin-specific protease 7 (USP7); interactions of vIRF-1 and vIRF-3 with USP7 promote PEL cell viability and regulate productive replication. Here, we report that vIRF-2 also targets USP7, utilizing a PSTS motif matching the USP7 N-terminal domain-binding A/PxxS consensus, but uniquely requires catalytic domain residues for intracellular interaction. In functional and mechanistic analyses, tumor necrosis factor receptor-associated factor (TRAF)-mediated signaling and associated polyubiquitination of TRAFs 3 and 6, specifically, were regulated negatively by USP7 and positively by vIRF-2-USP7 interaction, the latter competing for USP7-TRAF association. Using depletion, depletion-complementation, and targeted mutagenesis approaches, vIRF-2 was determined to promote latent PEL cell viability, likely independently of USP7 interaction, while lytic replication was inhibited by vIRF-2, in part or in whole via USP7 interaction. Together, our data identify a new molecular determinant of USP7 recognition, TRAF3/6-specific targeting by the deubiquitinase, associated activation of these TRAFs by vIRF-2, and activities of vIRF-2 and vIRF-2-USP7 interaction in HHV-8 latent and lytic biology.IMPORTANCE Human herpesvirus 8-encoded IRF homologues were the first to be identified in a virus. Through inhibitory interactions with cellular IRFs and other mediators of antiviral signaling, the vIRFs are believed to be essential for productive replication and also for latency in particular cell types. The deubiquitinase USP7 is a regulator of key cellular pathways, modulates HHV-8 latent and lytic infection, and is targeted by vIRFs 1, 3, and 4. Here, we report that vIRF-2 also interacts with USP7, via a means distinguishable from USP7 interactions with other vIRFs and other proteins, that this interaction modulates antiviral signaling via disruption of USP7 interactions with innate immune signaling proteins TRAF3 and TRAF6, and that vIRF-2 targeting of USP7 regulates HHV-8 productive replication. The presented data are the first to identify vIRF-2 targeting of USP7 and its role in HHV-8 biology, expanding our understanding of the repertoire and importance of virus-host interactions.
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Affiliation(s)
- Qiwang Xiang
- Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Hyunwoo Ju
- Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - John Nicholas
- Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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8
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Yilmaz V, Strati K. Regulating cellular plasticity to persist: a way for tumor viruses to triumph. Curr Opin Virol 2019; 39:1-7. [PMID: 31302443 DOI: 10.1016/j.coviro.2019.06.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 06/12/2019] [Accepted: 06/13/2019] [Indexed: 12/11/2022]
Affiliation(s)
- Vural Yilmaz
- University of Cyprus, Department of Biological Sciences, 1 University Avenue, 2109, Nicosia, Cyprus
| | - Katerina Strati
- University of Cyprus, Department of Biological Sciences, 1 University Avenue, 2109, Nicosia, Cyprus.
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9
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He B, Tran JT, Sanchez DJ. Manipulation of Type I Interferon Signaling by HIV and AIDS-Associated Viruses. J Immunol Res 2019; 2019:8685312. [PMID: 31089479 PMCID: PMC6476103 DOI: 10.1155/2019/8685312] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 02/14/2019] [Indexed: 12/20/2022] Open
Abstract
Type I Interferons were first described for their profound antiviral abilities in cell culture and animal models, and later, they were translated into potent antiviral therapeutics. However, as additional studies into the function of Type I Interferons progressed, it was also seen that pathogenic viruses have coevolved to encode potent mechanisms allowing them to evade or suppress the impact of Type I Interferons on their replication. For chronic viral infections, such as HIV and many of the AIDS-associated viruses, including HTLV, HCV, KSHV, and EBV, the clinical efficacy of Type I Interferons is limited by these mechanisms. Here, we review some of the ways that HIV and AIDS-associated viruses thrive in Type I Interferon-rich environments via mechanisms that block the function of this important antiviral cytokine. Overall, a better understanding of these mechanisms creates avenues to better understand the innate immune response to these viruses as well as plan the development of antivirals that would allow the natural antiviral effect of Type I Interferons to manifest during these infections.
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Affiliation(s)
- Buyuan He
- Pharmaceutical Sciences Department, College of Pharmacy, Western University of Health Sciences, Pomona 91766, California, USA
| | - James T. Tran
- Pharmaceutical Sciences Department, College of Pharmacy, Western University of Health Sciences, Pomona 91766, California, USA
| | - David Jesse Sanchez
- Pharmaceutical Sciences Department, College of Pharmacy, Western University of Health Sciences, Pomona 91766, California, USA
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10
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Fatima I, Kanwal S, Mahmood T. Natural Products Mediated Targeting of Virally Infected Cancer. Dose Response 2019; 17:1559325818813227. [PMID: 30670935 PMCID: PMC6328957 DOI: 10.1177/1559325818813227] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Revised: 10/01/2018] [Accepted: 10/10/2018] [Indexed: 12/18/2022] Open
Abstract
The role of viral infection in developing cancer was determined in the start of 20th century. Until now, 8 different virus-associated cancers have been discovered and most of them progressed in immunosuppressed individuals. The aim of the present study is to look into the benefits of natural products in treating virally infected cancers. The study focuses on bioactive compounds derived from natural sources. Numerous pharmaceutical agents have been identified from plants (vincristine, vinblastine, stilbenes, combretastatin, and silymarin), marine organisms (bryostatins, cephalostatin, ecteinascidins, didemnin, and dolastatin), insects (cantharidin, mastoparan, parectadial, and cecropins), and microorganisms (vancomycin, rhizoxin, ansamitocins, mitomycin, and rapamycin). Beside these, various compounds have been observed from fruits and vegetables which can be utilized in anticancer therapy. These include curcumin in turmeric, resveratrol in red grapes, S-allyl cysteine in allium, allicin in garlic, catechins in green tea, and β-carotene in carrots. The present study addresses various types of virally infected cancers, their mechanism of action, and the role of different cell surface molecules elicited during viral binding and entry into the target cell along with the anticancer drugs derived from natural products by targeting screening of bioactive compounds from natural sources.
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Affiliation(s)
- Iram Fatima
- Department of Plant Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
| | - Sobia Kanwal
- Department of Zoology, University of Gujrat Sub-campus Rawalpindi, Rawalpindi, Pakistan
| | - Tariq Mahmood
- Department of Plant Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, Pakistan
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11
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Mariggiò G, Koch S, Schulz TF. Kaposi sarcoma herpesvirus pathogenesis. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0275. [PMID: 28893942 PMCID: PMC5597742 DOI: 10.1098/rstb.2016.0275] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/09/2017] [Indexed: 12/15/2022] Open
Abstract
Kaposi sarcoma herpesvirus (KSHV), taxonomical name human gammaherpesvirus 8, is a phylogenetically old human virus that co-evolved with human populations, but is now only common (seroprevalence greater than 10%) in sub-Saharan Africa, around the Mediterranean Sea, parts of South America and in a few ethnic communities. KSHV causes three human malignancies, Kaposi sarcoma, primary effusion lymphoma, and many cases of the plasmablastic form of multicentric Castleman's disease (MCD) as well as occasional cases of plasmablastic lymphoma arising from MCD; it has also been linked to rare cases of bone marrow failure and hepatitis. As it has colonized humans physiologically for many thousand years, cofactors are needed to allow it to unfold its pathogenic potential. In most cases, these include immune defects of genetic, iatrogenic or infectious origin, and inflammation appears to play an important role in disease development. Our much improved understanding of its life cycle and its role in pathogenesis should now allow us to develop new therapeutic strategies directed against key viral proteins or intracellular pathways that are crucial for virus replication or persistence. Likewise, its limited (for a herpesvirus) distribution and transmission should offer an opportunity for the development and use of a vaccine to prevent transmission. This article is part of the themed issue ‘Human oncogenic viruses’.
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Affiliation(s)
- Giuseppe Mariggiò
- Institute of Virology, Hannover Medical School, Carl Neuberg Strasse 1, 30625 Hannover, Germany.,German Centre for Infection Research, Hannover-Braunschweig site, Hannover, Germany
| | - Sandra Koch
- Institute of Virology, Hannover Medical School, Carl Neuberg Strasse 1, 30625 Hannover, Germany.,German Centre for Infection Research, Hannover-Braunschweig site, Hannover, Germany
| | - Thomas F Schulz
- Institute of Virology, Hannover Medical School, Carl Neuberg Strasse 1, 30625 Hannover, Germany .,German Centre for Infection Research, Hannover-Braunschweig site, Hannover, Germany
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12
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Marsili G, Perrotti E, Remoli AL, Acchioni C, Sgarbanti M, Battistini A. IFN Regulatory Factors and Antiviral Innate Immunity: How Viruses Can Get Better. J Interferon Cytokine Res 2018; 36:414-32. [PMID: 27379864 DOI: 10.1089/jir.2016.0002] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The interferon regulatory factor (IRF) family consists of transcriptional regulators that exert multifaceted and versatile functions in multiple biological processes. Their crucial role as central mediators in the establishment and execution of host immunity in response to pathogen-derived signals downstream pattern recognition receptors (PRRs) makes IRFs a hallmark of the host antiviral response. They function as hub molecules at the crossroad of different signaling pathways for the induction of interferon (IFN) and inflammatory cytokines, as well as of antiviral and immunomodulatory genes even in an IFN-independent manner. By regulating the development and activity of immune cells, IRFs also function as a bridge between innate and adaptive responses. As such, IRFs represent attractive and compulsive targets in viral strategies to subvert antiviral signaling. In this study, we discuss current knowledge on the wide array of strategies put in place by pathogenic viruses to evade, subvert, and/or hijack these essential components of host antiviral immunity.
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Affiliation(s)
- Giulia Marsili
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità , Rome, Italy
| | - Edvige Perrotti
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità , Rome, Italy
| | - Anna Lisa Remoli
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità , Rome, Italy
| | - Chiara Acchioni
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità , Rome, Italy
| | - Marco Sgarbanti
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità , Rome, Italy
| | - Angela Battistini
- Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità , Rome, Italy
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Watanabe T, Sugimoto A, Hosokawa K, Fujimuro M. Signal Transduction Pathways Associated with KSHV-Related Tumors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1045:321-355. [PMID: 29896674 DOI: 10.1007/978-981-10-7230-7_15] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Signal transduction pathways play a key role in the regulation of cell growth, cell differentiation, cell survival, apoptosis, and immune responses. Bacterial and viral pathogens utilize the cell signal pathways by encoding their own proteins or noncoding RNAs to serve their survival and replication in infected cells. Kaposi's sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus 8 (HHV-8), is classified as a rhadinovirus in the γ-herpesvirus subfamily and was the eighth human herpesvirus to be discovered from Kaposi's sarcoma specimens. KSHV is closely associated with an endothelial cell malignancy, Kaposi's sarcoma, and B-cell malignancies, primary effusion lymphoma, and multicentric Castleman's disease. Recent studies have revealed that KSHV manipulates the cellular signaling pathways to achieve persistent infection, viral replication, cell proliferation, anti-apoptosis, and evasion of immune surveillance in infected cells. This chapter summarizes recent developments in our understanding of the molecular mechanisms used by KSHV to interact with the cell signaling machinery.
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Affiliation(s)
- Tadashi Watanabe
- Department of Cell Biology, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Atsuko Sugimoto
- Department of Cell Biology, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Kohei Hosokawa
- Department of Cell Biology, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Masahiro Fujimuro
- Department of Cell Biology, Kyoto Pharmaceutical University, Kyoto, Japan.
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14
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Koch S, Schulz TF. Rhadinoviral interferon regulatory factor homologues. Biol Chem 2017; 398:857-870. [PMID: 28455950 DOI: 10.1515/hsz-2017-0111] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 04/20/2017] [Indexed: 01/17/2023]
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV), or human herpesvirus 8 (HHV8) is a gammaherpesvirus and the etiological agent of Kaposi's sarcoma, primary effusion lymphoma and multicentric Castleman disease. The KSHV genome contains genes for a unique group of proteins with homology to cellular interferon regulatory factors, termed viral interferon regulatory factors (vIRFs). This review will give an overview over the oncogenic, antiapoptotic and immunomodulatory characteristics of KSHV and related vIRFs.
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15
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Williamson SJ, Nicol SM, Stürzl M, Sabbah S, Hislop AD. Azidothymidine Sensitizes Primary Effusion Lymphoma Cells to Kaposi Sarcoma-Associated Herpesvirus-Specific CD4+ T Cell Control and Inhibits vIRF3 Function. PLoS Pathog 2016; 12:e1006042. [PMID: 27893813 PMCID: PMC5125715 DOI: 10.1371/journal.ppat.1006042] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 11/04/2016] [Indexed: 01/06/2023] Open
Abstract
Kaposi sarcoma-associated herpesvirus (KSHV) is linked with the development of Kaposi sarcoma and the B lymphocyte disorders primary effusion lymphoma (PEL) and multi-centric Castleman disease. T cell immunity limits KSHV infection and disease, however the virus employs multiple mechanisms to inhibit efficient control by these effectors. Thus KSHV-specific CD4+ T cells poorly recognize most PEL cells and even where they can, they are unable to kill them. To make KSHV-infected cells more sensitive to T cell control we treated PEL cells with the thymidine analogue azidothymidine (AZT), which sensitizes PEL lines to Fas-ligand and TRAIL challenge; effector mechanisms which T cells use. PELs co-cultured with KSHV-specific CD4+ T cells in the absence of AZT showed no control of PEL outgrowth. However in the presence of AZT PEL outgrowth was controlled in an MHC-restricted manner. To investigate how AZT sensitizes PELs to immune control we first examined BJAB cells transduced with individual KSHV-latent genes for their ability to resist apoptosis mediated by stimuli delivered through Fas and TRAIL receptors. This showed that in addition to the previously described vFLIP protein, expression of vIRF3 also inhibited apoptosis delivered by these stimuli. Importantly vIRF3 mediated protection from these apoptotic stimuli was inhibited in the presence of AZT as was a second vIRF3 associated phenotype, the downregulation of surface MHC class II. Although both vFLIP and vIRF3 are expressed in PELs, we propose that inhibiting vIRF3 function with AZT may be sufficient to restore T cell control of these tumor cells. Kaposi sarcoma-associated herpesvirus (KSHV) can cause disease in humans in the form of B lymphocyte disorders such as primary effusion lymphoma (PEL) and multicentric Castleman disease. Where tested, these are highly resistant to immune control by KSHV-specific T cells. To investigate how such KSHV-infected cells can be made more sensitive to T cell control we treated PEL lines with azidothymidine (AZT), which has been shown to induce sensitivity in such lines to the mechanisms which T cells use to kill targets. We found this allowed the T cells to control in vitro lymphoma growth. The ability of the T cells to control PEL cell growth was found to correlate with AZT mediated inhibition of function of the KSHV protein vIRF3 which we show has the ability to protect cells from killing by immune effector mechanisms. These studies suggest that the therapeutic drug AZT may be of use to tip the virus host balance away from the virus by interfering with this immune evasion and pro-survival protein, potentially allowing better control by the host.
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Affiliation(s)
- Samantha J. Williamson
- Institute of Immunology and Immunotherapy, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Samantha M. Nicol
- Institute of Immunology and Immunotherapy, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Michael Stürzl
- Division of Molecular and Experimental Surgery, Department of Surgery, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Shereen Sabbah
- Department of Immunobiology, King's College London, London, United Kingdom
| | - Andrew D. Hislop
- Institute of Immunology and Immunotherapy, University of Birmingham, Edgbaston, Birmingham, United Kingdom
- * E-mail:
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Cha S, Choe J, Seo T. vIRF3 encoded by Kaposi's sarcoma-associated herpesvirus inhibits T-cell factor-dependent transcription via a CREB-binding protein-interaction motif. Biochem Biophys Res Commun 2016; 479:697-702. [DOI: 10.1016/j.bbrc.2016.09.150] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 09/28/2016] [Indexed: 01/14/2023]
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17
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Crow MS, Lum KK, Sheng X, Song B, Cristea IM. Diverse mechanisms evolved by DNA viruses to inhibit early host defenses. Crit Rev Biochem Mol Biol 2016; 51:452-481. [PMID: 27650455 PMCID: PMC5285405 DOI: 10.1080/10409238.2016.1226250] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
In mammalian cells, early defenses against infection by pathogens are mounted through a complex network of signaling pathways shepherded by immune-modulatory pattern-recognition receptors. As obligate parasites, the survival of viruses is dependent on the evolutionary acquisition of mechanisms that tactfully dismantle and subvert the cellular intrinsic and innate immune responses. Here, we review the diverse mechanisms by which viruses that accommodate DNA genomes are able to circumvent activation of cellular immunity. We start by discussing viral manipulation of host defense protein levels by either transcriptional regulation or protein degradation. We next review viral strategies used to repurpose or inhibit these cellular immune factors by molecular hijacking or by regulating their post-translational modification status. Additionally, we explore the infection-induced temporal modulation of apoptosis to facilitate viral replication and spread. Lastly, the co-evolution of viruses with their hosts is highlighted by the acquisition of elegant mechanisms for suppressing host defenses via viral mimicry of host factors. In closing, we present a perspective on how characterizing these viral evasion tactics both broadens the understanding of virus-host interactions and reveals essential functions of the immune system at the molecular level. This knowledge is critical in understanding the sources of viral pathogenesis, as well as for the design of antiviral therapeutics and autoimmunity treatments.
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Affiliation(s)
- Marni S. Crow
- Department of Molecular Biology, Princeton University, Lewis Thomas Laboratory, Washington Road, Princeton, NJ 08544
| | - Krystal K. Lum
- Department of Molecular Biology, Princeton University, Lewis Thomas Laboratory, Washington Road, Princeton, NJ 08544
| | - Xinlei Sheng
- Department of Molecular Biology, Princeton University, Lewis Thomas Laboratory, Washington Road, Princeton, NJ 08544
| | - Bokai Song
- Department of Molecular Biology, Princeton University, Lewis Thomas Laboratory, Washington Road, Princeton, NJ 08544
| | - Ileana M. Cristea
- Department of Molecular Biology, Princeton University, Lewis Thomas Laboratory, Washington Road, Princeton, NJ 08544
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18
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Abstract
Multicentric Castleman disease (MCD) encompasses a spectrum of conditions that give rise to overlapping clinicopathological manifestations. The fundamental pathogenetic mechanism involves dysregulated cytokine activity that causes systemic inflammatory symptoms as well as lymphadenopathy. The histological changes in lymph nodes resemble in part the findings originally described in the unicentric forms Castleman disease, both hyaline vascular and plasma cell variants. In MCD caused by Kaposi sarcoma-associated herpesvirus/human herpesvirus-8 (KSHV/HHV8), the cytokine over activity is caused by viral products, which can also lead to atypical lymphoproliferations and potential progression to lymphoma. In cases negative for KSHV/HHV8, so-called idiopathic MCD, the hypercytokinemia can result from various mechanisms, which ultimately lead to different constellations of clinical presentations and varied pathology in lymphoid tissues. In this article, we review the evolving concepts and definitions of the various conditions under the eponym of Castleman disease, and summarize current knowledge regarding the histopathology and pathogenesis of lesions within the MCD spectrum.
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Affiliation(s)
- Hao-Wei Wang
- Hematopathology Section, Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - Stefania Pittaluga
- Hematopathology Section, Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD
| | - Elaine S Jaffe
- Hematopathology Section, Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD.
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Purushothaman P, Uppal T, Sarkar R, Verma SC. KSHV-Mediated Angiogenesis in Tumor Progression. Viruses 2016; 8:E198. [PMID: 27447661 PMCID: PMC4974533 DOI: 10.3390/v8070198] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 06/18/2016] [Accepted: 07/07/2016] [Indexed: 12/14/2022] Open
Abstract
Human herpesvirus 8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus (KSHV), is a malignant human oncovirus belonging to the gamma herpesvirus family. HHV-8 is closely linked to the pathogenesis of Kaposi's sarcoma (KS) and two other B-cell lymphoproliferative diseases: primary effusion lymphoma (PEL) and a plasmablastic variant of multicentric Castleman's disease (MCD). KS is an invasive tumor of endothelial cells most commonly found in untreated HIV-AIDS or immuno-compromised individuals. KS tumors are highly vascularized and have abnormal, excessive neo-angiogenesis, inflammation, and proliferation of infected endothelial cells. KSHV directly induces angiogenesis in an autocrine and paracrine fashion through a complex interplay of various viral and cellular pro-angiogenic and inflammatory factors. KS is believed to originate due to a combination of KSHV's efficient strategies for evading host immune systems and several pro-angiogenic and pro-inflammatory stimuli. In addition, KSHV infection of endothelial cells produces a wide array of viral oncoproteins with transforming capabilities that regulate multiple host-signaling pathways involved in the activation of angiogenesis. It is likely that the cellular-signaling pathways of angiogenesis and lymph-angiogenesis modulate the rate of tumorigenesis induction by KSHV. This review summarizes the current knowledge on regulating KSHV-mediated angiogenesis by integrating the findings reported thus far on the roles of host and viral genes in oncogenesis, recent developments in cell-culture/animal-model systems, and various anti-angiogenic therapies for treating KSHV-related lymphoproliferative disorders.
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Affiliation(s)
- Pravinkumar Purushothaman
- Department of Microbiology and Immunology, University of Nevada, Reno, School of Medicine, 1664 N Virginia Street, MS 320, Reno, NV 89557, USA.
| | - Timsy Uppal
- Department of Microbiology and Immunology, University of Nevada, Reno, School of Medicine, 1664 N Virginia Street, MS 320, Reno, NV 89557, USA.
| | - Roni Sarkar
- Department of Microbiology and Immunology, University of Nevada, Reno, School of Medicine, 1664 N Virginia Street, MS 320, Reno, NV 89557, USA.
| | - Subhash C Verma
- Department of Microbiology and Immunology, University of Nevada, Reno, School of Medicine, 1664 N Virginia Street, MS 320, Reno, NV 89557, USA.
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20
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Karouni M, Kurban M, Abbas O. Plasmacytoid dendritic cells in skin lesions of classic Kaposi's sarcoma. Arch Dermatol Res 2016; 308:487-92. [PMID: 27372661 DOI: 10.1007/s00403-016-1671-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 06/05/2016] [Accepted: 06/27/2016] [Indexed: 11/29/2022]
Abstract
Plasmacytoid dendritic cells (pDCs) are the most potent producers of type I interferons (IFNs), which allows them to provide anti-viral resistance and to link the innate and adaptive immunity by controlling the function of myeloid DCs, lymphocytes, and natural killer cells. pDCs are involved in the pathogenesis of several infectious [especially viral, such as Molluscum contagiosum (MC)], inflammatory/autoimmune, and neoplastic entities. Kaposi's sarcoma (KS) is a multifocal, systemic lympho-angioproliferative tumor associated with Kaposi's sarcoma-associated herpesvirus (KSHV) infection. Microscopy typically exhibits a chronic inflammatory lymphoplasmacytic infiltrate in addition to the vascular changes and spindle cell proliferation. Despite the extensive research done on the immune evasion strategies employed by KSHV, pDCs role in relation to KS has only rarely been investigated. Given this, we intend to investigate pDC occurrence and activity in the skin lesions of KS. Immunohistochemical staining for BDCA-2 (specific pDC marker) and MxA (surrogate marker for local type I IFN production) was performed on classic KS (n = 20) with the control group comprising inflamed MC (n = 20). As expected, BDCA-2+ pDCs were present in abundance with diffuse and intense MxA expression (indicative of local type I IFN production) in all inflamed MC cases (20 of 20, 100 %). Though present in all the KS cases, pDCs were significantly less abundant in KS than in inflamed MC cases, and MxA expression was patchy/weak in most KS cases. In summary, pDCs are part of the inflammatory host response in KS; however, they were generally low in number with decreased type I IFN production which is probably related to KSHV's ability to evade the immune system through the production of different viral proteins capable of suppressing IFN production as well as pDC function.
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Affiliation(s)
- Mirna Karouni
- Dermatology Department, American University of Beirut Medical Center, Riad El Solh St, P.O.Box 11-0236, Beirut, Lebanon
| | - Mazen Kurban
- Dermatology Department, American University of Beirut Medical Center, Riad El Solh St, P.O.Box 11-0236, Beirut, Lebanon
| | - Ossama Abbas
- Dermatology Department, American University of Beirut Medical Center, Riad El Solh St, P.O.Box 11-0236, Beirut, Lebanon.
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21
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Banerjee S, Uppal T, Strahan R, Dabral P, Verma SC. The Modulation of Apoptotic Pathways by Gammaherpesviruses. Front Microbiol 2016; 7:585. [PMID: 27199919 PMCID: PMC4847483 DOI: 10.3389/fmicb.2016.00585] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Accepted: 04/11/2016] [Indexed: 12/11/2022] Open
Abstract
Apoptosis or programmed cell death is a tightly regulated process fundamental for cellular development and elimination of damaged or infected cells during the maintenance of cellular homeostasis. It is also an important cellular defense mechanism against viral invasion. In many instances, abnormal regulation of apoptosis has been associated with a number of diseases, including cancer development. Following infection of host cells, persistent and oncogenic viruses such as the members of the Gammaherpesvirus family employ a number of different mechanisms to avoid the host cell’s “burglar” alarm and to alter the extrinsic and intrinsic apoptotic pathways by either deregulating the expressions of cellular signaling genes or by encoding the viral homologs of cellular genes. In this review, we summarize the recent findings on how gammaherpesviruses inhibit cellular apoptosis via virus-encoded proteins by mediating modification of numerous signal transduction pathways. We also list the key viral anti-apoptotic proteins that could be exploited as effective targets for novel antiviral therapies in order to stimulate apoptosis in different types of cancer cells.
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Affiliation(s)
- Shuvomoy Banerjee
- Amity Institute of Virology and Immunology, Amity University Noida, India
| | - Timsy Uppal
- Department of Microbiology and Immunology, Center for Molecular Medicine, School of Medicine, University of Nevada, Reno Reno, NV, USA
| | - Roxanne Strahan
- Department of Microbiology and Immunology, Center for Molecular Medicine, School of Medicine, University of Nevada, Reno Reno, NV, USA
| | - Prerna Dabral
- Department of Microbiology and Immunology, Center for Molecular Medicine, School of Medicine, University of Nevada, Reno Reno, NV, USA
| | - Subhash C Verma
- Department of Microbiology and Immunology, Center for Molecular Medicine, School of Medicine, University of Nevada, Reno Reno, NV, USA
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22
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Lee HR, Amatya R, Jung JU. Multi-step regulation of innate immune signaling by Kaposi's sarcoma-associated herpesvirus. Virus Res 2015; 209:39-44. [PMID: 25796211 PMCID: PMC4575611 DOI: 10.1016/j.virusres.2015.03.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 03/06/2015] [Accepted: 03/09/2015] [Indexed: 12/15/2022]
Abstract
The innate immune system provides an immediate and relatively non-specific response to infection with the aim of eliminating the pathogen before an infection can be fully established. Activation of innate immune response is achieved by production of pro-inflammatory cytokines and type I interferon (IFN). The IFN response in particular is one of the primary defenses utilized by the host innate immune system to control pathogen infection, like virus infection. Hence, viruses have learned to manipulate host immune control mechanisms to facilitate their propagation. Due to this, much work has been dedicated to the elucidation of the Kaposi's sarcoma-associated herpesvirus (KSHV)-mediated immune evasion tactics that antagonize a host's immune system. This review presents our current knowledge of the immune evasion strategies employed by KSHV at distinct stages of its life cycle to control a host's immune system with a focus on interferon signaling.
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Affiliation(s)
- Hye-Ra Lee
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Harlyne J. Norris Cancer Research Tower, 1450 Biggy Street, Los Angeles, CA 90033, USA.
| | - Rina Amatya
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Harlyne J. Norris Cancer Research Tower, 1450 Biggy Street, Los Angeles, CA 90033, USA
| | - Jae U Jung
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Harlyne J. Norris Cancer Research Tower, 1450 Biggy Street, Los Angeles, CA 90033, USA; Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, HMR Rm 401, 2011 Zonal Avenue, Los Angeles, CA 90033, USA
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23
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Schulz TF, Cesarman E. Kaposi Sarcoma-associated Herpesvirus: mechanisms of oncogenesis. Curr Opin Virol 2015; 14:116-28. [PMID: 26431609 DOI: 10.1016/j.coviro.2015.08.016] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 08/30/2015] [Indexed: 10/23/2022]
Abstract
Kaposi Sarcoma-associated Herpesvirus (KSHV, HHV8) causes three human malignancies, Kaposi Sarcoma (KS), an endothelial tumor, as well as Primary Effusion Lymphoma (PEL) and the plasma cell variant of Multicentric Castleman's Disease (MCD), two B-cell lymphoproliferative diseases. All three cancers occur primarily in the context of immune deficiency and/or HIV infection, but their pathogenesis differs. KS most likely results from the combined effects of an endotheliotropic virus with angiogenic properties and inflammatory stimuli and thus represents an interesting example of a cancer that arises in an inflammatory context. Viral and cellular angiogenic and inflammatory factors also play an important role in the pathogenesis of MCD. In contrast, PEL represents an autonomously growing malignancy that is, however, still dependent on the continuous presence of KSHV and the action of several KSHV proteins.
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Affiliation(s)
- Thomas F Schulz
- Institute of Virology, Hannover Medical School, Hannover, Germany; German Centre of Infection Research, Hannover-Braunschweig Site, Hannover, Germany.
| | - Ethel Cesarman
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, USA.
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24
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Matar CG, Jacobs NT, Speck SH, Lamb TJ, Moormann AM. Does EBV alter the pathogenesis of malaria? Parasite Immunol 2015; 37:433-45. [DOI: 10.1111/pim.12212] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 05/20/2015] [Indexed: 02/06/2023]
Affiliation(s)
- C. G. Matar
- Department of Microbiology and Immunology; Emory University School of Medicine; Atlanta GA USA
| | - N. T. Jacobs
- Department of Pediatrics; Emory University School of Medicine; Atlanta GA USA
| | - S. H. Speck
- Department of Microbiology and Immunology; Emory University School of Medicine; Atlanta GA USA
- Emory Vaccine Center; Emory University; Atlanta GA USA
| | - T. J. Lamb
- Department of Pediatrics; Emory University School of Medicine; Atlanta GA USA
| | - A. M. Moormann
- Program in Molecular Medicine; University of Massachusetts Medical School; Worcester MA USA
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25
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A Rhesus Rhadinovirus Viral Interferon (IFN) Regulatory Factor Is Virion Associated and Inhibits the Early IFN Antiviral Response. J Virol 2015; 89:7707-21. [PMID: 25972548 DOI: 10.1128/jvi.01175-15] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 05/08/2015] [Indexed: 01/14/2023] Open
Abstract
UNLABELLED The interferon (IFN) response is the earliest host immune response dedicated to combating viral infection. As such, viruses have evolved strategies to subvert this potent antiviral response. Two closely related gammaherpesviruses, Kaposi's sarcoma-associated herpesvirus (KSHV) and rhesus macaque rhadinovirus (RRV), are unique in that they express viral homologues to cellular interferon regulatory factors (IRFs), termed viral IRFs (vIRFs). Cellular IRFs are a family of transcription factors that are particularly important for the transcription of type I IFNs. Here, we demonstrate a strategy employed by RRV to ensure rapid inhibition of virus-induced type I IFN induction. We found that RRV vIRF R6, when expressed ectopically, interacts with a transcriptional coactivator, CREB-binding protein (CBP), in the nucleus. As a result, phosphorylated IRF3, an important transcriptional regulator in beta interferon (IFN-β) transcription, fails to effectively bind to the IFN-β promoter, thus inhibiting the activation of IFN-β genes. In addition, we found R6 within RRV virion particles via immunoelectron microscopy and, furthermore, that virion-associated R6 is capable of inhibiting the type I IFN response by preventing efficient binding of IRF3/CBP complexes to the IFN-β promoter in the context of infection. The work shown here is the first example of a vIRF being associated with either the KSHV or RRV virion. The presence of this immunomodulatory protein in the RRV virion provides the virus with an immediate mechanism to evade the host IFN response, thus enabling the virus to effectively establish an infection within the host. IMPORTANCE Kaposi's sarcoma-associated herpesvirus (KSHV) and the closely related rhesus macaque rhadinovirus (RRV) are the only viruses known to encode viral homologues to cellular interferon regulatory factors (IRFs), known as vIRFs. In KSHV, these proteins have been shown to play major roles in a variety of cellular processes and are particularly important in the evasion of the host type I interferon (IFN) response. In this study, we delineate the immunomodulatory mechanism of an RRV vIRF and its ability to assist the virus in rapid immune evasion by being prepackaged within the virion, thus providing evidence, for the first time, of a virion-associated vIRF. This work further contributes to our understanding of the mechanisms behind immunomodulation by the RRV vIRFs during infection.
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26
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Kumari P, Narayanan S, Kumar H. Herpesviruses: interfering innate immunity by targeting viral sensing and interferon pathways. Rev Med Virol 2015; 25:187-201. [DOI: 10.1002/rmv.1836] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 03/03/2015] [Accepted: 03/04/2015] [Indexed: 12/26/2022]
Affiliation(s)
- Puja Kumari
- Laboratory of Immunology, Department of Biological Sciences; Indian Institute of Science Education and Research (IISER); Bhopal India
| | - Sathish Narayanan
- Laboratory of Virology, Department of Biological Sciences; Indian Institute of Science Education and Research (IISER); Bhopal India
| | - Himanshu Kumar
- Laboratory of Immunology, Department of Biological Sciences; Indian Institute of Science Education and Research (IISER); Bhopal India
- Laboratory of Host Defense; WPI Immunology Frontier Research Centre, Osaka University; Osaka Japan
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27
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Abstract
ABSTRACT Viruses have evolved to subvert host cell pathways to enable their replication and persistence. In particular, virus-encoded gene products target the host's immune system to evade elimination by antiviral immune defenses. Cytokines are soluble, secreted proteins, which regulate many aspects of immune responses, by providing signals through cell surface receptors on target cells. Cytokine pathways are therefore attractive targets for modulation by viruses during their replication cycle. This review deals with modulation of cytokine pathways by the human herpesvirus, a family of viruses that are capable of life-long persistence in the host and cause severe disease particularly in immunocompromised individuals.
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28
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IRF5 is a novel regulator of CXCL13 expression in breast cancer that regulates CXCR5
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B‐ and T‐cell trafficking to tumor‐conditioned media. Immunol Cell Biol 2014; 93:486-99. [DOI: 10.1038/icb.2014.110] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 11/25/2014] [Accepted: 11/25/2014] [Indexed: 02/07/2023]
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29
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Interferon induction by RNA viruses and antagonism by viral pathogens. Viruses 2014; 6:4999-5027. [PMID: 25514371 PMCID: PMC4276940 DOI: 10.3390/v6124999] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 11/04/2014] [Accepted: 12/04/2014] [Indexed: 12/22/2022] Open
Abstract
Interferons are a group of small proteins that play key roles in host antiviral innate immunity. Their induction mainly relies on host pattern recognition receptors (PRR). Host PRR for RNA viruses include Toll-like receptors (TLR) and retinoic acid-inducible gene I (RIG-I) like receptors (RLR). Activation of both TLR and RLR pathways can eventually lead to the secretion of type I IFNs, which can modulate both innate and adaptive immune responses against viral pathogens. Because of the important roles of interferons, viruses have evolved multiple strategies to evade host TLR and RLR mediated signaling. This review focuses on the mechanisms of interferon induction and antagonism of the antiviral strategy by RNA viruses.
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30
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Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV; also known as human herpesvirus 8) is the etiologic agent of Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease. These cancers often occur in the context of immunosuppression, which has made KSHV-associated malignancies an increasing global health concern with the persistence of the AIDS epidemic. KSHV has also been linked to several acute inflammatory diseases. KSHV exists between a lytic and latent lifecycle, which allows the virus to transition between active replication and quiescent infection. KSHV encodes a number of proteins and small RNAs that are thought to inadvertently transform host cells while performing their functions of helping the virus persist in the infected host. KSHV also has an arsenal of components that aid the virus in evading the host immune response, which help the virus establish a successful lifelong infection. In this comprehensive chapter, we will discuss the diseases associated with KSHV infection, the biology of latent and lytic infection, and individual proteins and microRNAs that are known to contribute to host cell transformation and immune evasion.
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Affiliation(s)
- Louise Giffin
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Blossom Damania
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
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31
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Hu Z, Usherwood EJ. Immune escape of γ-herpesviruses from adaptive immunity. Rev Med Virol 2014; 24:365-78. [PMID: 24733560 DOI: 10.1002/rmv.1791] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 03/06/2014] [Accepted: 03/07/2014] [Indexed: 01/23/2023]
Abstract
Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV) are two γ-herpesviruses identified in humans and are strongly associated with the development of malignancies. Murine γ-herpesvirus (MHV-68) is a naturally occurring rodent pathogen, representing a unique experimental model for dissecting γ-herpesvirus infection and the immune response. These γ-herpesviruses actively antagonize the innate and adaptive antiviral responses, thereby efficiently establishing latent or persistent infections and even promoting development of malignancies. In this review, we summarize immune evasion strategies of γ-herpesviruses. These include suppression of MHC-I-restricted and MHC-II-restricted antigen presentation, impairment of dendritic cell functions, downregulation of costimulatory molecules, activation of virus-specific regulatory T cells, and induction of inhibitory cytokines. There is a focus on how both γ-herpesvirus-derived and host-derived immunomodulators interfere with adaptive antiviral immunity. Understanding immune-evasive mechanisms is essential for developing future immunotherapies against EBV-driven and KSHV-driven tumors.
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Affiliation(s)
- Zhuting Hu
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Lebanon, NH, USA
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Cousins E, Nicholas J. Molecular biology of human herpesvirus 8: novel functions and virus-host interactions implicated in viral pathogenesis and replication. Recent Results Cancer Res 2014; 193:227-68. [PMID: 24008302 PMCID: PMC4124616 DOI: 10.1007/978-3-642-38965-8_13] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Human herpesvirus 8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus (KSHV), is the second identified human gammaherpesvirus. Like its relative Epstein-Barr virus, HHV-8 is linked to B-cell tumors, specifically primary effusion lymphoma and multicentric Castleman's disease, in addition to endothelial-derived KS. HHV-8 is unusual in its possession of a plethora of "accessory" genes and encoded proteins in addition to the core, conserved herpesvirus and gammaherpesvirus genes that are necessary for basic biological functions of these viruses. The HHV-8 accessory proteins specify not only activities deducible from their cellular protein homologies but also novel, unsuspected activities that have revealed new mechanisms of virus-host interaction that serve virus replication or latency and may contribute to the development and progression of virus-associated neoplasia. These proteins include viral interleukin-6 (vIL-6), viral chemokines (vCCLs), viral G protein-coupled receptor (vGPCR), viral interferon regulatory factors (vIRFs), and viral antiapoptotic proteins homologous to FLICE (FADD-like IL-1β converting enzyme)-inhibitory protein (FLIP) and survivin. Other HHV-8 proteins, such as signaling membrane receptors encoded by open reading frames K1 and K15, also interact with host mechanisms in unique ways and have been implicated in viral pathogenesis. Additionally, a set of micro-RNAs encoded by HHV-8 appear to modulate expression of multiple host proteins to provide conditions conducive to virus persistence within the host and could also contribute to HHV-8-induced neoplasia. Here, we review the molecular biology underlying these novel virus-host interactions and their potential roles in both virus biology and virus-associated disease.
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Affiliation(s)
- Emily Cousins
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, 1650 Orleans Street, Baltimore, MD, 21287, USA,
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Cai Q, Banerjee S, Cervini A, Lu J, Hislop AD, Dzeng R, Robertson ES. IRF-4-mediated CIITA transcription is blocked by KSHV encoded LANA to inhibit MHC II presentation. PLoS Pathog 2013; 9:e1003751. [PMID: 24204280 PMCID: PMC3814934 DOI: 10.1371/journal.ppat.1003751] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Accepted: 09/23/2013] [Indexed: 01/18/2023] Open
Abstract
Peptides presentation to T cells by MHC class II molecules is of importance in initiation of immune response to a pathogen. The level of MHC II expression directly influences T lymphocyte activation and is often targeted by various viruses. Kaposi's sarcoma-associated herpesvirus (KSHV) encoded LANA is known to evade MHC class I peptide processing, however, the effect of LANA on MHC class II remains unclear. Here, we report that LANA down-regulates MHC II expression and presentation by inhibiting the transcription of MHC II transactivator (CIITA) promoter pIII and pIV in a dose-dependent manner. Strikingly, although LANA knockdown efficiently disrupts the inhibition of CIITA transcripts from its pIII and pIV promoter region, the expression of HLA-DQβ but no other MHC II molecules was significantly restored. Moreover, we revealed that the presentation of HLA-DQβ enhanced by LANA knockdown did not help LANA-specific CD4+ T cell recognition of PEL cells, and the inhibition of CIITA by LANA is independent of IL-4 or IFN-γ signaling but dependent on the direct interaction of LANA with IRF-4 (an activator of both the pIII and pIV CIITA promoters). This interaction dramatically blocked the DNA-binding ability of IRF-4 on both pIII and pIV promoters. Thus, our data implies that LANA can evade MHC II presentation and suppress CIITA transcription to provide a unique strategy of KSHV escape from immune surveillance by cytotoxic T cells.
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Affiliation(s)
- Qiliang Cai
- MOE&MOH Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, People's Republic of China
| | - Shuvomoy Banerjee
- Department of Microbiology and the Tumor Virology Program of Abramson Comprehensive Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States of America
| | - Amanda Cervini
- Department of Microbiology and the Tumor Virology Program of Abramson Comprehensive Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States of America
| | - Jie Lu
- Department of Microbiology and the Tumor Virology Program of Abramson Comprehensive Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States of America
| | - Andrew D. Hislop
- School of Cancer Sciences and Medical Research Council Centre for Immune Regulation, The University of Birmingham, Birmingham, United Kingdom
| | - Richard Dzeng
- Department of Microbiology and the Tumor Virology Program of Abramson Comprehensive Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States of America
| | - Erle S. Robertson
- Department of Microbiology and the Tumor Virology Program of Abramson Comprehensive Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, United States of America
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Distinct roles of Kaposi's sarcoma-associated herpesvirus-encoded viral interferon regulatory factors in inflammatory response and cancer. J Virol 2013; 87:9398-410. [PMID: 23785197 DOI: 10.1128/jvi.03315-12] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiologic agent associated with Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman disease (MCD). Similar to other herpesviruses, KSHV has two life cycles, latency and lytic replication. In latency, the KSHV genome persists as a circular episome in the nucleus of the host cell and only a few viral genes are expressed. In this review, we focus on oncogenic, antiapoptotic, and immunomodulating properties of KSHV-encoded homologues of cellular interferon regulatory factors (IRFs)--viral IRF1 (vIRF1) to vIRF4--and their possible role in the KSHV-mediated antiviral response, apoptosis, and oncogenicity.
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Feng P, Moses A, Früh K. Evasion of adaptive and innate immune response mechanisms by γ-herpesviruses. Curr Opin Virol 2013; 3:285-95. [PMID: 23735334 DOI: 10.1016/j.coviro.2013.05.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 05/01/2013] [Accepted: 05/14/2013] [Indexed: 01/05/2023]
Abstract
γ-Herpesviral immune evasion mechanisms are optimized to support the acute, lytic and the longterm, latent phase of infection. During acute infection, specific immune modulatory proteins limit, but also exploit, the antiviral activities of cell intrinsic innate immune responses as well as those of innate and adaptive immune cells. During latent infection, a restricted gene expression program limits immune targeting and cis-acting mechanisms to reduce the antigen presentation as well as antigenicity of latency-associated proteins. Here, we will review recent progress in our understanding of γ-herpesviral immune evasion strategies.
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Affiliation(s)
- Pinghui Feng
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA
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36
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Jochmann R, Pfannstiel J, Chudasama P, Kuhn E, Konrad A, Stürzl M. O-GlcNAc transferase inhibits KSHV propagation and modifies replication relevant viral proteins as detected by systematic O-GlcNAcylation analysis. Glycobiology 2013; 23:1114-30. [PMID: 23580777 DOI: 10.1093/glycob/cwt028] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
O-GlcNAcylation is an inducible, highly dynamic and reversible post-translational modification, mediated by a unique enzyme named O-linked N-acetyl-d-glucosamine (O-GlcNAc) transferase (OGT). In response to nutrients, O-GlcNAc levels are differentially regulated on many cellular proteins involved in gene expression, translation, immune reactions, protein degradation, protein-protein interaction, apoptosis and signal transduction. In contrast to eukaryotic cells, little is known about the role of O-GlcNAcylation in the viral life cycle. Here, we show that the overexpression of the OGT reduces the replication efficiency of Kaposi's sarcoma-associated herpesvirus (KSHV) in a dose-dependent manner. In order to investigate the global impact of O-GlcNAcylation in the KSHV life cycle, we systematically analyzed the 85 annotated KSHV-encoded open reading frames for O-GlcNAc modification. For this purpose, an immunoprecipitation (IP) strategy with three different approaches was carried out and the O-GlcNAc signal of the identified proteins was properly controlled for specificity. Out of the 85 KSHV-encoded proteins, 18 proteins were found to be direct targets for O-GlcNAcylation. Selected proteins were further confirmed by mass spectrometry for O-GlcNAc modification. Correlation of the functional annotation and the O-GlcNAc status of KSHV proteins showed that the predominant targets were proteins involved in viral DNA synthesis and replication. These results indicate that O-GlcNAcylation plays a major role in the regulation of KSHV propagation.
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Affiliation(s)
- Ramona Jochmann
- Division of Molecular and Experimental Surgery, University Medical Center Erlangen, Friedrich-Alexander University of Erlangen-Nuremberg, Schwabachanlage 10, 91054 Erlangen, Germany
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37
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Brice A, Moseley GW. Viral interactions with microtubules: orchestrators of host cell biology? Future Virol 2013. [DOI: 10.2217/fvl.12.137] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Viral interaction with the microtubule (MT) cytoskeleton is critical to infection by many viruses. Most data regarding virus–MT interaction indicate key roles in the subcellular transport of virions/viral genomic material to sites of replication, assembly and egress. However, the MT cytoskeleton orchestrates diverse processes in addition to subcellular cargo transport, including regulation of signaling pathways, cell survival and mitosis, suggesting that viruses, expert manipulators of the host cell, may use the virus–MT interface to control multiple aspects of cell biology. Several lines of evidence support this idea, indicating that specific viral proteins can modify MT dynamics and/or structure and regulate processes such as apoptosis and innate immune signaling through MT-dependent mechanisms. Here, the authors review general aspects of virus–MT interactions, with emphasis on viral mechanisms that modify MT dynamics and functions to affect processes beyond virion transport. The emerging importance of discrete viral protein–MT interactions in pathogenic processes indicates that these interfaces may represent new targets for future therapeutics and vaccine development.
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Affiliation(s)
- Aaron Brice
- Viral Immune Evasion & Pathogenicity Laboratory, Department of Biochemistry & Molecular Biology, Monash University, Victoria 3800, Australia
| | - Gregory W Moseley
- Viral Immune Evasion & Pathogenicity Laboratory, Department of Biochemistry & Molecular Biology, Monash University, Victoria 3800, Australia.
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Kaposi's sarcoma-associated herpesvirus-encoded viral IRF3 modulates major histocompatibility complex class II (MHC-II) antigen presentation through MHC-II transactivator-dependent and -independent mechanisms: implications for oncogenesis. J Virol 2013; 87:5340-50. [PMID: 23449805 DOI: 10.1128/jvi.00250-13] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Evasion of immune T cell responses is crucial for persistent viruses to establish a normal carrier state. Most studies on active immune modulation mechanisms have focused on the stage of virus production in infected cells, when large numbers of viral antigens and potential immune modulators are expressed. For oncogenic viruses such as Kaposi's sarcoma-associated herpesvirus (KSHV), which is carried as a lifelong infection, usually with little harmful effect, but can cause various tumors, the immune evasion strategies can also be relevant in the context of tumorigenesis. Here we report that the virus-encoded interferon regulatory factor 3 (vIRF3) latent viral gene expressed in KSHV-related tumors functions as a potent immunevasin. Expression of vIRF3 downregulates surface major histocompatibility complex class II (MHC-II) DR expression with slow kinetics but, more importantly, can substantially inhibit recognition by KSHV-specific CD4 T cells prior to its effects on MHC-II DR downregulation in model cell systems. This property of vIRF3 is only partly due to its ability to inhibit the transcription of CIITA and, thus, MHC-II expression; CIITA-independent inhibition of MHC-II transcripts and another as yet unidentified posttranscriptional mechanism are also involved in qualitatively modulating the availability of specific peptide/MHC-II complexes at the cell surface. Consistent with these observations, the vIRF3-expressing KSHV-associated primary effusion lymphoma (PEL) lines are generally resistant to recognition by KSHV-specific CD4 T cells. Interestingly, some PEL lines exhibit small subpopulations with lower vIRF3 expression that can be recognized. These data implicate vIRF3 as a critical determinant of the MHC-II antigen presentation function in KSHV-associated PELs that is likely to be important in the pathogenesis of these tumors.
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39
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Kaposi's sarcoma-associated herpesvirus lana2 protein interacts with the pocket proteins and inhibits their sumoylation. Oncogene 2013; 33:495-503. [PMID: 23318443 DOI: 10.1038/onc.2012.603] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 10/29/2012] [Accepted: 11/07/2012] [Indexed: 12/16/2022]
Abstract
The pocket proteins retinoblastoma protein (pRb), p107 and p130 are the key targets of oncoproteins expressed by DNA tumor viruses. Some of these viral proteins contain an LXCXE motif that mediates the interaction with the three pocket proteins and the inhibition of the pRb SUMOylation. Kaposi's sarcoma herpesvirus (KSHV) contains at least two proteins that can regulate pRb function but, so far, a KSHV-encoded protein targeting p107 and p130 has not been identified. Here, we show that the KSHV latent protein LANA2 binds to pRb, p107 and p130. LANA2 contains an LXCXE motif that is required for bypassing pRb-mediated cell-cycle arrest and for inhibiting pRb SUMOylation. Finally, we demonstrate that, in addition to pRb, both p107 and p130 can be SUMOylated, and this modification is also inhibited by LANA2 in an LXCXE-dependent manner. These results demonstrate, for the first time, the SUMOylation of p107 or p130 and, so far, they represent the first example of a KSHV protein able to interact with the three pocket proteins and to inhibit their conjugation to SUMO.
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Jacobs SR, Gregory SM, West JA, Wollish AC, Bennett CL, Blackbourn DJ, Heise MT, Damania B. The viral interferon regulatory factors of kaposi's sarcoma-associated herpesvirus differ in their inhibition of interferon activation mediated by toll-like receptor 3. J Virol 2013; 87:798-806. [PMID: 23115281 PMCID: PMC3554052 DOI: 10.1128/jvi.01851-12] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 10/23/2012] [Indexed: 01/11/2023] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) infection is correlated with three human malignancies and can establish lifelong latent infection in multiple cell types within its human host. In order to establish and maintain infection, KSHV utilizes multiple mechanisms to evade the host immune response. One such mechanism is the expression of a family of genes with homology to cellular interferon (IFN) regulatory factors (IRFs), known as viral IRFs (vIRFs). We demonstrate here that KSHV vIRF1, -2, and -3 have a differential ability to block type I interferon signaling mediated by Toll-like receptor 3 (TLR3), a receptor we have previously shown to be activated upon KSHV infection. vIRF1, -2, and -3 inhibited TLR3-driven activation of IFN transcription reporters. However, only vIRF1 and vIRF2 inhibited increases in both IFN-β message and protein levels following TLR3 activation. The expression of vIRF1 and vIRF2 also allowed for increased replication of a virus known to activate TLR3 signaling. Furthermore, vIRF1 and vIRF2 may block TLR3-mediated signaling via different mechanisms. Altogether, this report indicates that vIRFs are able to block IFN mediated by TLRs but that each vIRF has a unique function and mechanism for blocking antiviral IFN responses.
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Affiliation(s)
- Sarah R. Jacobs
- Lineberger Comprehensive Cancer Center and Department of Microbiology & Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Sean M. Gregory
- Lineberger Comprehensive Cancer Center and Department of Microbiology & Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - John A. West
- Lineberger Comprehensive Cancer Center and Department of Microbiology & Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Amy C. Wollish
- Department of Genetics and Department of Microbiology and Immunology, the Carolina Vaccine Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Christopher L. Bennett
- Lineberger Comprehensive Cancer Center and Department of Microbiology & Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - David J. Blackbourn
- School of Cancer Sciences and Cancer Research United Kingdom Centre, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Mark T. Heise
- Department of Genetics and Department of Microbiology and Immunology, the Carolina Vaccine Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Blossom Damania
- Lineberger Comprehensive Cancer Center and Department of Microbiology & Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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41
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Ostermann E, Tuddenham L, Macquin C, Alsaleh G, Schreiber-Becker J, Tanguy M, Bahram S, Pfeffer S, Georgel P. Deregulation of type I IFN-dependent genes correlates with increased susceptibility to cytomegalovirus acute infection of dicer mutant mice. PLoS One 2012; 7:e43744. [PMID: 22916300 PMCID: PMC3423365 DOI: 10.1371/journal.pone.0043744] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Accepted: 07/23/2012] [Indexed: 11/19/2022] Open
Abstract
Regulation of gene expression by microRNAs (miRNAs) is now considered as an essential mechanism for cell development and homeostasis. Indeed, numerous studies have reported that modulating their expression, maturation, or activity can affect cell survival, identity or activation. In particular, miRNAs are key players in the tight regulation of signaling cascades, and as such, they appear as perfectly suited immunomodulators. Several immune-related processes, including inflammation, have recently been demonstrated to require specific miRNAs. In addition, the discovery of herpesvirus-encoded miRNAs has reinforced this assumption. To decipher the potential roles of miRNAs in innate antiviral immune response, we developed an in vivo model based on the inoculation of mouse cytomegalovirus (MCMV) in mice. Furthermore, we exploited a mouse line carrying a hypomorphic mutation in the Dicer gene to visualize the impact of impaired miRNA biogenesis upon the anti-MCMV response. Our data indicate that miRNAs are important actors in mounting an efficient response against herpesviruses. We suggest that a rapid and transient interferon response following viral infection requires miRNA-dependent repressor release. In addition, our in vivo efforts identified several miRNA targets, thus providing a conceptual framework for future analyzes on the regulation of specific actors involved in the Type I interferon pathway.
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Affiliation(s)
- Eleonore Ostermann
- Université de Strasbourg, EA 4438 Laboratoire d'Immunogénétique Moléculaire Humaine, Strasbourg, France
| | - Lee Tuddenham
- Université de Strasbourg, Architecture et Réactivité de l′ARN, Institut de Biologie Moléculaire et Cellulaire du CNRS, Strasbourg, France
| | - Cecile Macquin
- Université de Strasbourg, EA 4438 Laboratoire d'Immunogénétique Moléculaire Humaine, Strasbourg, France
| | - Ghada Alsaleh
- Université de Strasbourg, EA 4438 Laboratoire de Physiopathologie des arthrites, Illkirch, France
| | - Julie Schreiber-Becker
- Université de Strasbourg, Architecture et Réactivité de l′ARN, Institut de Biologie Moléculaire et Cellulaire du CNRS, Strasbourg, France
| | - Melanie Tanguy
- Université de Strasbourg, Architecture et Réactivité de l′ARN, Institut de Biologie Moléculaire et Cellulaire du CNRS, Strasbourg, France
| | - Seiamak Bahram
- Université de Strasbourg, EA 4438 Laboratoire d'Immunogénétique Moléculaire Humaine, Strasbourg, France
| | - Sebastien Pfeffer
- Université de Strasbourg, Architecture et Réactivité de l′ARN, Institut de Biologie Moléculaire et Cellulaire du CNRS, Strasbourg, France
- * E-mail: (SP); (PG)
| | - Philippe Georgel
- Université de Strasbourg, EA 4438 Laboratoire d'Immunogénétique Moléculaire Humaine, Strasbourg, France
- * E-mail: (SP); (PG)
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Human herpesvirus 8 interferon regulatory factor-mediated BH3-only protein inhibition via Bid BH3-B mimicry. PLoS Pathog 2012; 8:e1002748. [PMID: 22685405 PMCID: PMC3369933 DOI: 10.1371/journal.ppat.1002748] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 04/27/2012] [Indexed: 12/17/2022] Open
Abstract
Viral replication efficiency is in large part governed by the ability of viruses to counteract pro-apoptotic signals induced by infection of host cells. For HHV-8, viral interferon regulatory factor-1 (vIRF-1) contributes to this process in part via inhibitory interactions with BH3-only protein (BOP) Bim, recently identified as an interaction partner of vIRF-1. Here we recognize that the Bim-binding domain (BBD) of vIRF-1 resembles a region (BH3-B) of Bid, another BOP, which interacts intramolecularly with the functional BH3 domain of Bid to inhibit it pro-apoptotic activity. Indeed, vIRF-1 was found to target Bid in addition to Bim and to interact, via its BBD region, with the BH3 domain of each. In functional assays, BBD could substitute for BH3-B in the context of Bid, to suppress Bid-induced apoptosis in a BH3-binding-dependent manner, and vIRF-1 was able to protect transfected cells from apoptosis induced by Bid. While vIRF-1 can mediate nuclear sequestration of Bim, this was not the case for Bid, and inhibition of Bid and Bim by vIRF-1 could occur independently of nuclear localization of the viral protein. Consistent with this finding, direct BBD-dependent inactivation by vIRF-1 of Bid-induced mitochondrial permeabilization was demonstrable in vitro and isolated BBD sequences were also active in this assay. In addition to Bim and Bid BH3 domains, BH3s of BOPs Bik, Bmf, Hrk, and Noxa also were found to bind BBD, while those of both pro- and anti-apoptotic multi-BH domain Bcl-2 proteins were not. Finally, the significance of Bid to virus replication was demonstrated via Bid-depletion in HHV-8 infected cells, which enhanced virus production. Together, our data demonstrate and characterize BH3 targeting and associated inhibition of BOP pro-apoptotic activity by vIRF-1 via Bid BH3-B mimicry, identifying a novel mechanism of viral evasion from host cell defenses. Viruses possess mechanisms of subverting host cell defenses against infection and virus replication; these mechanisms are essential to the virus life cycle. Here, we identify and characterize a novel mechanism of HHV-8 mediated inhibition of virus-induced programmed cell death (apoptosis). This function is specified by viral interferon regulator factor homologue vIRF-1, which binds to and directly inhibits pro-death activities of so-called BH3-only proteins (BOPs), induced and activated by stress signals such as those occurring in infected cells. The BH3 domains of BOPs mediate their pro-apoptotic functions, and it is these domains that are targeted by vIRF-1, via a region resembling a BH3-interacting and -inhibitory domain, termed BH3-B, present in one of the vIRF-1 targeted BOPs, Bid. The targeted BOP BH3 domains share characteristic and conserved features. As shown previously for Bim, depletion of Bid leads to enhanced HHV-8 productive replication, demonstrating that Bid, also, is a biologically significant negative regulator of virus replication and suggesting that its control by vIRF-1 is of functional importance. To our knowledge, this is the first report of viral targeting and inhibition of BOP activity via Bid BH3-B mimicry; our studies therefore expand the known mechanisms of viral evasion from antiviral defenses of the host.
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Sarek G, Ma L, Enbäck J, Järviluoma A, Moreau P, Haas J, Gessain A, Koskinen PJ, Laakkonen P, Ojala PM. Kaposi's sarcoma herpesvirus lytic replication compromises apoptotic response to p53 reactivation in virus-induced lymphomas. Oncogene 2012; 32:1091-8. [PMID: 22469985 DOI: 10.1038/onc.2012.118] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Primary effusion lymphomas (PELs) are aggressive Kaposi's sarcoma herpesvirus (KSHV)-induced malignancies with median survival time <6 months post-diagnosis. Mutations in the TP53 gene seldom occur in PELs, suggesting that genetic alterations in the TP53 are not selected during PEL progression. We have reported that p53 reactivation by an inhibitor of the p53-MDM2 interaction, Nutlin-3, induces selective and massive apoptosis in PEL cells leading to efficient anti-tumor activity in a subcutaneous xenograft model for PEL. Here, we show compelling anti-tumor activity of Nutlin-3 in the majority of intraperitoneal PEL xenografts in vivo. Interestingly, our results demonstrate that spontaneous induction of viral lytic replication in tumors could drastically attenuate the p53-dependent apoptotic response to Nutlin-3. Moreover, viral reactivation compromised p53-dependent apoptosis in PEL cells treated with genotoxic anti-cancer agents doxorubicin and etoposide. We have recently demonstrated that the Ser/Thr kinases Pim 1 and 3 are required to trigger induction of the lytic replication cascade of KSHV. We have now assessed the ability of a novel Pim kinase inhibitor to restore the Nutlin-3-induced cytotoxicity in lytic PEL cells. PEL cells induced to lytic replication by phorbol esters showed 50% inhibition of active viral replication following treatment with the Pim kinase inhibitor. Importantly, co-treatment of these cells with the kinase inhibitor and Nutlin-3 resulted in a robust restoration of the Nutlin-3-induced cell death. These results highlight the potential impact of activation of viral lytic replication on disease progression and response to treatment in KSHV-induced lymphomas.
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Affiliation(s)
- G Sarek
- Institute of Biotechnology & Research Programs Unit, Genome-Scale-Biology, Biomedicum Helsinki, Institute of Biomedicine, University of Helsinki, Helsinki, Finland
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Baresova P, Pitha PM, Lubyova B. Kaposi sarcoma-associated herpesvirus vIRF-3 protein binds to F-box of Skp2 protein and acts as a regulator of c-Myc protein function and stability. J Biol Chem 2012; 287:16199-208. [PMID: 22453922 DOI: 10.1074/jbc.m111.335216] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The Kaposi sarcoma-associated herpesvirus (KSHV) has been linked to Kaposi sarcoma, body cavity-based lymphoma, and Castleman disease. vIRF-3 is a KSHV latent gene that is critical for proliferation of KSHV-positive lymphoid cells. Furthermore, vIRF-3 contributes to KSHV-associated pathogenesis by stimulating c-Myc transcription activity. Here we show that vIRF-3 can associate with Skp2, a key component of the SCF(skp2) ubiquitin ligase complex. Skp2 is a transcriptional co-factor for c-Myc that was shown to regulate the stability of c-Myc protein as well as c-Myc-dependent transcription. In this study, we show that vIRF-3 binds to the F-box of Skp2 and recruits it to c-Myc-regulated promoters to activate c-Myc-dependent transcription. Additionally, cells overexpressing vIRF-3 exhibit higher levels of c-Myc ubiquitylation, suggesting that ubiquitylation is necessary for c-Myc-mediated transcription. Moreover, vIRF-3 can stabilize the c-Myc protein by increasing its half-life. Collectively, these results indicate that vIRF-3 can effectively manipulate c-Myc stability and function and thus contribute to c-Myc-induced KSHV-associated lymphomagenesis.
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Affiliation(s)
- Petra Baresova
- Institute of Immunology and Microbiology, First Medical Faculty of Charles University, 12800 Prague, Czech Republic
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45
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Lee HR, Brulois K, Wong L, Jung JU. Modulation of Immune System by Kaposi's Sarcoma-Associated Herpesvirus: Lessons from Viral Evasion Strategies. Front Microbiol 2012; 3:44. [PMID: 22403573 PMCID: PMC3293256 DOI: 10.3389/fmicb.2012.00044] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2011] [Accepted: 01/27/2012] [Indexed: 12/14/2022] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV), a member of the herpesvirus family, has evolved to establish a long-term, latent infection of cells such that while they carry the viral genome gene expression is highly restricted. Latency is a state of cryptic viral infection associated with genomic persistence in their host and this hallmark of KSHV infection leads to several clinical-epidemiological diseases such as KS, a plasmablastic variant of multicentric Castleman's disease, and primary effusion lymphoma upon immune suppression of infected hosts. In order to sustain efficient life-long persistency as well as their life cycle, KSHV dedicates a large portion of its genome to encode immunomodulatory proteins that antagonize its host's immune system. In this review, we will describe our current knowledge of the immune evasion strategies employed by KSHV at distinct stages of its viral life cycle to control the host's immune system.
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Affiliation(s)
- Hye-Ra Lee
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California Los Angeles, CA, USA
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Robinson BA, Estep RD, Messaoudi I, Rogers KS, Wong SW. Viral interferon regulatory factors decrease the induction of type I and type II interferon during rhesus macaque rhadinovirus infection. J Virol 2012; 86:2197-211. [PMID: 22156526 PMCID: PMC3302421 DOI: 10.1128/jvi.05047-11] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Accepted: 11/17/2011] [Indexed: 01/20/2023] Open
Abstract
Kaposi's sarcoma-associated herpesvirus and rhesus macaque rhadinovirus (RRV), two closely related gammaherpesviruses, are unique in their expression of viral homologs of cellular interferon regulatory factors (IRFs), termed viral IRFs (vIRFs). To assess the role of vIRFs during de novo infection, we have utilized the bacterial artificial chromosome clone of wild-type RRV(17577) (WT(BAC) RRV) to generate a recombinant virus with all 8 of the vIRFs deleted (vIRF-ko RRV). The infection of primary rhesus fibroblasts and peripheral blood mononuclear cells (PBMCs) with vIRF-ko RRV resulted in earlier and increased induction of type I interferon (IFN) (IFN-α/β) and type II IFN (IFN-γ). Additionally, plasmacytoid dendritic cells maintained higher levels of IFN-α production in PBMC cultures infected with vIRF-ko RRV than in cultures infected with WT(BAC) RRV. Moreover, the nuclear accumulation of phosphorylated IRF-3, which is necessary for the induction of type I IFN, was also inhibited following WT(BAC) RRV infection. These findings demonstrate that during de novo RRV infection, vIRFs are inhibiting the induction of IFN at the transcriptional level, and one potential mechanism for this is the disruption of the activation and localization of IRF-3.
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Affiliation(s)
- Bridget A. Robinson
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, USA
- Vaccine and Gene Therapy Institute, Oregon Health & Science University, Beaverton, Oregon, USA
| | - Ryan D. Estep
- Vaccine and Gene Therapy Institute, Oregon Health & Science University, Beaverton, Oregon, USA
| | - Ilhem Messaoudi
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, USA
- Vaccine and Gene Therapy Institute, Oregon Health & Science University, Beaverton, Oregon, USA
- Division of Pathobiology and Immunology, Oregon National Primate Research Center, Beaverton, Oregon, USA
| | - Kelsey S. Rogers
- Vaccine and Gene Therapy Institute, Oregon Health & Science University, Beaverton, Oregon, USA
| | - Scott W. Wong
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, USA
- Vaccine and Gene Therapy Institute, Oregon Health & Science University, Beaverton, Oregon, USA
- Division of Pathobiology and Immunology, Oregon National Primate Research Center, Beaverton, Oregon, USA
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T-cell immunity to Kaposi sarcoma-associated herpesvirus: recognition of primary effusion lymphoma by LANA-specific CD4+ T cells. Blood 2012; 119:2083-92. [PMID: 22234686 DOI: 10.1182/blood-2011-07-366476] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
T-cell immunity is important for controlling Kaposi sarcoma-associated herpesvirus (KSHV) diseases such as the endothelial cell malignancy Kaposi sarcoma, or the B-cell malignancy, primary effusion lymphoma (PEL). However, little is known about KSHV-specific T-cell immunity in healthy donors and immune control of disease. Using PBMCs from healthy KSHV-infected donors, we found weak ex vivo responses to the KSHV latent antigens LANA, vFLIP, vCyclin, and Kaposin, with LANA most frequently recognized. CD4(+) T-cell clones specific to LANA, a protein expressed in all KSHV-infected cells and malignancies, were established to determine whether they could recognize LANA-expressing cells. B-cell targets expressing or fed LANA protein were consistently recognized by the clones; however, most PEL cell lines were not. PELs express the KSHV protein vIRF3 that inhibits promoter function of the HLA class II transactivator, decreasing expression of genes controlled by this transactivator. Re-expressing the class II transactivator in the PELs increased expression of downstream targets such as HLA class II and restored recognition but not killing by the LANA-specific clones. We suggest that PELs are poorly controlled in vivo because of inefficient recognition and killing by T cells.
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Viral interferon regulatory factors are critical for delay of the host immune response against rhesus macaque rhadinovirus infection. J Virol 2011; 86:2769-79. [PMID: 22171275 DOI: 10.1128/jvi.05657-11] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) and the closely related gamma-2 herpesvirus rhesus macaque (RM) rhadinovirus (RRV) are the only known viruses to encode viral homologues of the cellular interferon (IFN) regulatory factors (IRFs). Recent characterization of a viral IRF (vIRF) deletion clone of RRV (vIRF-knockout RRV [vIRF-ko RRV]) demonstrated that vIRFs inhibit induction of type I and type II IFNs during RRV infection of peripheral blood mononuclear cells. Because the IFN response is a key component to a host's antiviral defenses, this study has investigated the role of vIRFs in viral replication and the development of the immune response during in vivo infection in RMs, the natural host of RRV. Experimental infection of RMs with vIRF-ko RRV resulted in decreased viral loads and diminished B cell hyperplasia, a characteristic pathology during acute RRV infection that often develops into more severe lymphoproliferative disorders in immune-compromised animals, similar to pathologies in KSHV-infected individuals. Moreover, in vivo infection with vIRF-ko RRV resulted in earlier and sustained production of proinflammatory cytokines and earlier induction of an anti-RRV T cell response compared to wild-type RRV infection. These findings reveal the broad impact that vIRFs have on pathogenesis and the immune response in vivo and are the first to validate the importance of vIRFs during de novo infection in the host.
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Mandal P, Krueger BE, Oldenburg D, Andry KA, Beard RS, White DW, Barton ES. A gammaherpesvirus cooperates with interferon-alpha/beta-induced IRF2 to halt viral replication, control reactivation, and minimize host lethality. PLoS Pathog 2011; 7:e1002371. [PMID: 22114555 PMCID: PMC3219715 DOI: 10.1371/journal.ppat.1002371] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Accepted: 09/26/2011] [Indexed: 02/06/2023] Open
Abstract
The gammaherpesviruses, including Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV), establish latency in memory B lymphocytes and promote lymphoproliferative disease in immunocompromised individuals. The precise immune mechanisms that prevent gammaherpesvirus reactivation and tumorigenesis are poorly defined. Murine gammaherpesvirus 68 (MHV68) is closely related to EBV and KSHV, and type I (alpha/beta) interferons (IFNαβ) regulate MHV68 reactivation from both B cells and macrophages by unknown mechanisms. Here we demonstrate that IFNβ is highly upregulated during latent infection, in the absence of detectable MHV68 replication. We identify an interferon-stimulated response element (ISRE) in the MHV68 M2 gene promoter that is bound by the IFNαβ-induced transcriptional repressor IRF2 during latency in vivo. The M2 protein regulates B cell signaling to promote establishment of latency and reactivation. Virus lacking the M2 ISRE (ISREΔ) overexpresses M2 mRNA and displays uncontrolled acute replication in vivo, higher latent viral load, and aberrantly high reactivation from latency. These phenotypes of the ISREΔ mutant are B-cell-specific, require IRF2, and correlate with a significant increase in virulence in a model of acute viral pneumonia. We therefore identify a mechanism by which a gammaherpesvirus subverts host IFNαβ signaling in a surprisingly cooperative manner, to directly repress viral replication and reactivation and enforce latency, thereby minimizing acute host disease. Since we find ISREs 5′ to the major lymphocyte latency genes of multiple rodent, primate, and human gammaherpesviruses, we propose that cooperative subversion of IFNαβ-induced IRFs to promote latent infection is an ancient strategy that ensures a stable, minimally-pathogenic virus-host relationship. Herpesviruses establish life-long infection in a non-replicating state termed latency. During immune compromise, herpesviruses can reactivate and cause severe disease, including cancer. We investigated mechanisms by which interferons alpha/beta (IFNαβ), a family of antiviral immune genes, inhibit reactivation of murine gammaherpesvirus 68 (MHV68). MHV68 is related to Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus, human gammaherpesviruses associated with multiple cancers. We made the surprising discovery that during latency, MHV68 cooperates with IFNαβ to inhibit its own replication. Specifically, a viral gene required for reactivation has evolved to be directly repressed by an IFNαβ-induced transcription factor, IRF2. Once virus replication has triggered sufficient IFNαβ production, expression of this viral gene is reduced and reactivation efficiency decreases. This strategy safeguards the health of the host, since a mutant virus that cannot respond to IRF2 replicates uncontrollably and is more virulent. Viral sensing of IFNαβ is also potentially subversive, since it allows MHV68 to detect periods of localized immune quiescence during which it can reactivate and spread to a new host. Thus, we highlight a novel path of virus-host coevolution, toward cooperative subversion of the antiviral immune response. These observations may illuminate new targets for drugs to inhibit herpesvirus reactivation or eliminate herpesvirus-associated tumors.
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Affiliation(s)
- Pratyusha Mandal
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America
- Department of Microbiology and Immunology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Bridgette E. Krueger
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America
| | - Darby Oldenburg
- Department of Health Professions, University of Wisconsin La Crosse, La Crosse, Wisconsin, United States of America
- Rheumatology Research Laboratory, Gundersen Lutheran Medical Center, La Crosse, Wisconsin, United States of America
| | - Katherine A. Andry
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America
| | - R. Suzanne Beard
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America
- Department of Microbiology and Immunology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Douglas W. White
- Rheumatology Research Laboratory, Gundersen Lutheran Medical Center, La Crosse, Wisconsin, United States of America
- Department of Microbiology, University of Wisconsin La Crosse, La Crosse, Wisconsin, United States of America
| | - Erik S. Barton
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America
- Department of Microbiology and Immunology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States of America
- * E-mail:
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Evasion and subversion of interferon-mediated antiviral immunity by Kaposi's sarcoma-associated herpesvirus: an overview. J Virol 2011; 85:10934-44. [PMID: 21775463 DOI: 10.1128/jvi.00687-11] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Viral invasion of a host cell triggers immune responses with both innate and adaptive components. The innate immune response involving the induction of type I interferons (alpha and beta interferons [IFN-α and -β]) constitutes the first line of antiviral defenses. The type I IFNs signal the transcription of a group of antiviral effector proteins, the IFN-stimulated genes (ISGs), which target distinct viral components and distinct stages of the viral life cycle, aiming to eliminate invading viruses. In the case of Kaposi's sarcoma-associated herpesvirus (KSHV), the etiological agent of Kaposi's sarcoma (KS), a sudden upsurge of type I IFN-mediated innate antiviral signals is seen immediately following both primary de novo infection and viral lytic reactivation from latency. Potent subversion of these responses thus becomes mandatory for the successful establishment of a primary infection following viral entry as well as for efficient viral assembly and egress. This review gives a concise overview of the induction of the type I IFN signaling pathways in response to viral infection and provides a comprehensive understanding of the antagonizing effects exerted by KSHV on type I IFN pathways wielded at various stages of the viral life cycle. Information garnered from this review should result in a better understanding of KSHV biology essential for the development of immunotherapeutic strategies targeted toward KSHV-associated malignancies.
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