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Torne AS, Robertson ES. Epigenetic Mechanisms in Latent Epstein-Barr Virus Infection and Associated Cancers. Cancers (Basel) 2024; 16:991. [PMID: 38473352 PMCID: PMC10931536 DOI: 10.3390/cancers16050991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 02/25/2024] [Accepted: 02/25/2024] [Indexed: 03/14/2024] Open
Abstract
The Epstein-Barr Virus (EBV) is a double-stranded DNA-based human tumor virus that was first isolated in 1964 from lymphoma biopsies. Since its initial discovery, EBV has been identified as a major contributor to numerous cancers and chronic autoimmune disorders. The virus is particularly efficient at infecting B-cells but can also infect epithelial cells, utilizing an array of epigenetic strategies to establish long-term latent infection. The association with histone modifications, alteration of DNA methylation patterns in host and viral genomes, and microRNA targeting of host cell factors are core epigenetic strategies that drive interactions between host and virus, which are necessary for viral persistence and progression of EBV-associated diseases. Therefore, understanding epigenetic regulation and its role in post-entry viral dynamics is an elusive area of EBV research. Here, we present current outlooks of EBV epigenetic regulation as it pertains to viral interactions with its host during latent infection and its propensity to induce tumorigenesis. We review the important epigenetic regulators of EBV latency and explore how the strategies involved during latent infection drive differential epigenetic profiles and host-virus interactions in EBV-associated cancers.
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Affiliation(s)
| | - Erle S. Robertson
- Tumor Virology Program, Department of Otorhinolaryngology-Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA;
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2
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Gouzouasis V, Tastsoglou S, Giannakakis A, Hatzigeorgiou AG. Virus-Derived Small RNAs and microRNAs in Health and Disease. Annu Rev Biomed Data Sci 2023; 6:275-298. [PMID: 37159873 DOI: 10.1146/annurev-biodatasci-122220-111429] [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] [Indexed: 05/11/2023]
Abstract
MicroRNAs (miRNAs) are short noncoding RNAs that can regulate all steps of gene expression (induction, transcription, and translation). Several virus families, primarily double-stranded DNA viruses, encode small RNAs (sRNAs), including miRNAs. These virus-derived miRNAs (v-miRNAs) help the virus evade the host's innate and adaptive immune system and maintain an environment of chronic latent infection. In this review, the functions of the sRNA-mediated virus-host interactions are highlighted, delineating their implication in chronic stress, inflammation, immunopathology, and disease. We provide insights into the latest viral RNA-based research-in silico approaches for functional characterization of v-miRNAs and other RNA types. The latest research can assist toward the identification of therapeutic targets to combat viral infections.
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Affiliation(s)
- Vasileios Gouzouasis
- Department of Molecular Biology and Genetics, Democritus University of Thrace, Alexandroupolis, Greece
- Laboratory of Molecular Genetics, Department of Immunology, Hellenic Pasteur Institute, Athens, Greece
- DIANA-Lab, Department of Computer Science and Biomedical Informatics, University of Thessaly, Lamia, Greece;
- DIANA-Lab, Hellenic Pasteur Institute, Athens, Greece
| | - Spyros Tastsoglou
- DIANA-Lab, Department of Computer Science and Biomedical Informatics, University of Thessaly, Lamia, Greece;
- DIANA-Lab, Hellenic Pasteur Institute, Athens, Greece
| | - Antonis Giannakakis
- Department of Molecular Biology and Genetics, Democritus University of Thrace, Alexandroupolis, Greece
- University Research Institute of Maternal and Child Health and Precision Medicine, UNESCO Chair on Adolescent Health Care, National and Kapodistrian University of Athens, Athens, Greece
| | - Artemis G Hatzigeorgiou
- DIANA-Lab, Department of Computer Science and Biomedical Informatics, University of Thessaly, Lamia, Greece;
- DIANA-Lab, Hellenic Pasteur Institute, Athens, Greece
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3
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Diggins NL, Hancock MH. Viral miRNA regulation of host gene expression. Semin Cell Dev Biol 2022; 146:2-19. [PMID: 36463091 PMCID: PMC10101914 DOI: 10.1016/j.semcdb.2022.11.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 11/16/2022] [Accepted: 11/22/2022] [Indexed: 12/05/2022]
Abstract
Viruses have evolved a multitude of mechanisms to combat barriers to productive infection in the host cell. Virally-encoded miRNAs are one such means to regulate host gene expression in ways that benefit the virus lifecycle. miRNAs are small non-coding RNAs that regulate protein expression but do not trigger the adaptive immune response, making them powerful tools encoded by viruses to regulate cellular processes. Diverse viruses encode for miRNAs but little sequence homology exists between miRNAs of different viral species. Despite this, common cellular pathways are targeted for regulation, including apoptosis, immune evasion, cell growth and differentiation. Herein we will highlight the viruses that encode miRNAs and provide mechanistic insight into how viral miRNAs aid in lytic and latent infection by targeting common cellular processes. We also highlight how viral miRNAs can mimic host cell miRNAs as well as how viral miRNAs have evolved to regulate host miRNA expression. These studies dispel the myth that viral miRNAs are subtle regulators of gene expression, and highlight the critical importance of viral miRNAs to the virus lifecycle.
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Affiliation(s)
- Nicole L Diggins
- Vaccine and Gene Therapy Institute, Oregon Health & Science University, Portland, OR, USA
| | - Meaghan H Hancock
- Vaccine and Gene Therapy Institute, Oregon Health & Science University, Portland, OR, USA.
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4
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Skalsky RL. MicroRNA-mediated control of Epstein-Barr virus infection and potential diagnostic and therapeutic implications. Curr Opin Virol 2022; 56:101272. [PMID: 36242893 DOI: 10.1016/j.coviro.2022.101272] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 09/07/2022] [Accepted: 09/15/2022] [Indexed: 11/03/2022]
Abstract
Herpesviruses, such as Epstein-Barr virus (EBV), encode multiple viral microRNAs that are expressed throughout various infection stages. While much progress has been made in evaluating both the viral and host microRNAs (miRNAs) that are detected during infection as well as elucidating their molecular targets in vitro, our understanding of their contributions to pathogenesis in vivo, viral oncogenesis, and clinical implications for these small molecules remains limited. miRNAs are widely recognized as key regulators of global cellular processes, including apoptosis, cell differentiation, and development of immune responses. This review discusses the roles of miRNAs in EBV infection and current advances in miRNA-based diagnostic and therapeutic strategies potentially applicable toward EBV-associated diseases.
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Affiliation(s)
- Rebecca L Skalsky
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Beaverton, OR, USA.
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5
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Heidari M, Zhang H, Sunkara L. MDV-induced differential microRNA expression in the primary lymphoid organ of thymus. Microb Pathog 2022; 170:105688. [PMID: 35917989 DOI: 10.1016/j.micpath.2022.105688] [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: 03/10/2022] [Revised: 07/12/2022] [Accepted: 07/19/2022] [Indexed: 11/20/2022]
Abstract
Marek's disease virus (MDV), a highly contagious cell associated virus, is the etiological agent of Marek's disease (MD), a lymphoproliferative and neuropathic disease of domestic chickens. Clinical signs of MD include transient paralysis, bursal/thymic atrophy, and T cell lymphomas. MicroRNAs (miRNAs) are short single-stranded non-coding RNAs that regulate gene expression by transcriptional suppression or mRNA degradation. Herpesviruses, including MDV, encode for miRNAs that are known to play essential roles in viral pathogenicity, oncogenesis, and evasion of immune responses. In this study, we performed miRNA sequencing in thymuses of control and MDV-infected chickens of MD-resistant (63) and susceptible (72) lines at 21 days post infection (dpi). The thymus is a lymphoid organ that undergoes severe atrophy due to MDV-induced apoptotic mediated destruction of T cells. Sequence analysis identified 658 total chicken miRNAs in the thymuses of control and MDV-infected birds of both lines. Of these, 453 were novel and 205 were known microRNAs. All novel miRNAs mapped to chicken genome with no sequence homology to existing miRNAs in the chicken miRbase. Comparative analysis between the thymuses of control and infected birds of resistant and susceptible lines identified 78 differentially expressed microRNAs that might provide insights into mechanisms of thymus atrophy.
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Affiliation(s)
- Mohammad Heidari
- Avian Disease and Oncology Laboratory, Agriculture Research Service, United States; Department of Agriculture, East Lansing, MI, USA.
| | - Huanmin Zhang
- Avian Disease and Oncology Laboratory, Agriculture Research Service, United States; Department of Agriculture, East Lansing, MI, USA.
| | - Lakshmi Sunkara
- Clemson Center for Human Genetics, Clemson University, Greenwood, SC, USA.
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6
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Zhou Y, Sotcheff SL, Routh AL. Next-generation sequencing: A new avenue to understand viral RNA-protein interactions. J Biol Chem 2022; 298:101924. [PMID: 35413291 PMCID: PMC8994257 DOI: 10.1016/j.jbc.2022.101924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 04/01/2022] [Accepted: 04/02/2022] [Indexed: 10/25/2022] Open
Abstract
The genomes of RNA viruses present an astonishing source of both sequence and structural diversity. From intracellular viral RNA-host interfaces to interactions between the RNA genome and structural proteins in virus particles themselves, almost the entire viral lifecycle is accompanied by a myriad of RNA-protein interactions that are required to fulfill their replicative potential. It is therefore important to characterize such rich and dynamic collections of viral RNA-protein interactions to understand virus evolution and their adaptation to their hosts and environment. Recent advances in next-generation sequencing technologies have allowed the characterization of viral RNA-protein interactions, including both transient and conserved interactions, where molecular and structural approaches have fallen short. In this review, we will provide a methodological overview of the high-throughput techniques used to study viral RNA-protein interactions, their biochemical mechanisms, and how they evolved from classical methods as well as one another. We will discuss how different techniques have fueled virus research to characterize how viral RNA and proteins interact, both locally and on a global scale. Finally, we will present examples on how these techniques influence the studies of clinically important pathogens such as HIV-1 and SARS-CoV-2.
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Affiliation(s)
- Yiyang Zhou
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, Texas, USA.
| | - Stephanea L Sotcheff
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, Texas, USA
| | - Andrew L Routh
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, Texas, USA; Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, Galveston, Texas, USA; Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, USA
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7
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Kondo S, Okuno Y, Murata T, Dochi H, Wakisaka N, Mizokami H, Moriyama-Kita M, Kobayashi E, Kano M, Komori T, Hirai N, Ueno T, Nakanishi Y, Endo K, Sugimoto H, Kimura H, Yoshizaki T. EBV genome variations enhance clinicopathological features of nasopharyngeal carcinoma in a non-endemic region. Cancer Sci 2022; 113:2446-2456. [PMID: 35485636 PMCID: PMC9277247 DOI: 10.1111/cas.15381] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 02/17/2022] [Accepted: 04/20/2022] [Indexed: 11/17/2022] Open
Abstract
Nasopharyngeal carcinoma (NPC) is caused by infection with Epstein–Barr virus (EBV) and endemic in certain geographic regions. EBV lytic gene, BALF2, closely associates with viral reactivation and BALF2 gene variation, the H‐H‐H strain, causes NPC in endemic region, southern China. Here, we investigate whether such EBV variations also affect NPC in a non‐endemic region, Japan. Viral genome sequencing with 47 EBV isolates of Japanese NPC were performed and compared with those of other EBV‐associated diseases from Japan or NPC in Southern China. EBV genomes of Japanese NPC are different from those of other diseases in Japan or endemic NPC; Japanese NPC was not affected by the endemic strain (the BALF2 H‐H‐H) but frequently carried the type 2 EBV or the strain with intermediate risk of endemic NPC (the BALF2 H‐H‐L). Seven single nucleotide variations were specifically associated with Japanese NPC, of which six were present in both type 1 and 2 EBV genomes, suggesting the contribution of the type 2 EBV‐derived haplotype. This observation was supported by a higher viral titer and stronger viral reactivation in NPC with either type 2 or H‐H‐L strains. Our results highlight the importance of viral strains and viral reactivation in the pathogenesis of non‐endemic NPC.
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Affiliation(s)
- Satoru Kondo
- Division of Otolaryngology and Head and Neck Surgery, Graduate School of Medical science, Kanazawa University. Kanazawa, Ishikawa, Japan.,These authors contributed equally to this work
| | - Yusuke Okuno
- Department of Virology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan.,Pediatric Cancer Treatment Center, Nagoya University Hospital, Nagoya, Aichi, Japan.,These authors contributed equally to this work
| | - Takayuki Murata
- Department of Virology and Parasitology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan
| | - Hirotomo Dochi
- Division of Otolaryngology and Head and Neck Surgery, Graduate School of Medical science, Kanazawa University. Kanazawa, Ishikawa, Japan
| | - Naohiro Wakisaka
- Division of Otolaryngology and Head and Neck Surgery, Graduate School of Medical science, Kanazawa University. Kanazawa, Ishikawa, Japan
| | - Harue Mizokami
- Division of Otolaryngology and Head and Neck Surgery, Graduate School of Medical science, Kanazawa University. Kanazawa, Ishikawa, Japan
| | - Makiko Moriyama-Kita
- Division of Otolaryngology and Head and Neck Surgery, Graduate School of Medical science, Kanazawa University. Kanazawa, Ishikawa, Japan
| | - Eiji Kobayashi
- Division of Otolaryngology and Head and Neck Surgery, Graduate School of Medical science, Kanazawa University. Kanazawa, Ishikawa, Japan
| | - Makoto Kano
- Division of Otolaryngology and Head and Neck Surgery, Graduate School of Medical science, Kanazawa University. Kanazawa, Ishikawa, Japan
| | - Takeshi Komori
- Division of Otolaryngology and Head and Neck Surgery, Graduate School of Medical science, Kanazawa University. Kanazawa, Ishikawa, Japan
| | - Nobuyuki Hirai
- Division of Otolaryngology and Head and Neck Surgery, Graduate School of Medical science, Kanazawa University. Kanazawa, Ishikawa, Japan
| | - Takayoshi Ueno
- Division of Otolaryngology and Head and Neck Surgery, Graduate School of Medical science, Kanazawa University. Kanazawa, Ishikawa, Japan
| | - Yosuke Nakanishi
- Division of Otolaryngology and Head and Neck Surgery, Graduate School of Medical science, Kanazawa University. Kanazawa, Ishikawa, Japan
| | - Kazuhira Endo
- Division of Otolaryngology and Head and Neck Surgery, Graduate School of Medical science, Kanazawa University. Kanazawa, Ishikawa, Japan
| | - Hisashi Sugimoto
- Division of Otolaryngology and Head and Neck Surgery, Graduate School of Medical science, Kanazawa University. Kanazawa, Ishikawa, Japan
| | - Hiroshi Kimura
- Department of Virology, Nagoya University, Graduate school of Medicine, Nagoya, Aichi, Japan
| | - Tomokazu Yoshizaki
- Division of Otolaryngology and Head and Neck Surgery, Graduate School of Medical science, Kanazawa University. Kanazawa, Ishikawa, Japan
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8
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Epstein-Barr virus miR-BHRF1-3 targets the BZLF1 3'UTR and regulates the lytic cycle. J Virol 2021; 96:e0149521. [PMID: 34878852 DOI: 10.1128/jvi.01495-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Suppression of lytic viral gene expression is a key aspect of the Epstein-Barr virus (EBV) life cycle to facilitate the establishment of latent infection. Molecular mechanisms regulating transitions between EBV lytic replication and latency are not fully understood. Here, we investigated the impact of viral microRNAs on the EBV lytic cycle. Through functional assays, we found that miR-BHRF1-3 attenuates EBV lytic gene expression following reactivation. To understand the miRNA targets contributing to this activity, we performed Ago PAR-CLIP analysis on EBV-positive, reactivated Burkitt's lymphoma cells and identified multiple miR-BHRF1-3 interactions with viral transcripts. Using luciferase reporter assays, we confirmed a miRNA interaction site within the 3'UTR of BZLF1 which encodes the essential immediate early (IE) transactivator Zta. Comparison of >850 published EBV genomes identified sequence polymorphisms within the miR-BHRF1-3 locus that deleteriously affect miRNA expression and function. Molecular interactions between the homologous viral miRNA, miR-rL1-17, and IE transcripts encoded by rhesus lymphocryptovirus were further identified. Our data demonstrate that regulation of IE gene expression by a BHRF1 miRNA is conserved amongst lymphocryptoviruses, and further reveal virally-encoded genetic elements that orchestrate viral antigen expression during the lytic cycle. Importance Epstein-Barr virus infection is predominantly latent in healthy individuals, while periodic cycles of reactivation are thought to facilitate persistent lifelong infection. Lytic infection has been linked to development of certain EBV-associated diseases. Here, we demonstrate that EBV miR-BHRF1-3 can suppress lytic replication by directly inhibiting Zta expression. Moreover, we identify nucleotide variants that impact the function of miR-BHRF1-3, which may contribute to specific EBV pathologies.
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9
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Shi D, Zhang Y, Mao T, Liu D, Liu W, Luo B. MiR-BART2-3p targets Unc-51-like kinase 1 and inhibits cell autophagy and migration in Epstein-Barr virus-associated gastric cancer. Virus Res 2021; 305:198567. [PMID: 34555439 DOI: 10.1016/j.virusres.2021.198567] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 09/01/2021] [Accepted: 09/07/2021] [Indexed: 12/29/2022]
Abstract
ULK1 (Unc-51-like kinase 1) is an evolutionarily conserved serine/threonine kinase that plays a central role in the regulation of autophagy. ULK1 is associated with prognosis for metastasis and survival in several tumors. However, its relationship with Epstein-Barr virus (EBV) has not been studied. We found that the expression of ULK1 in EBV-associated gastric cancer cells was lower than that in EBV-negative gastric cancer cells. Further, a luciferase reporter gene assay showed that miR-BART2-3p directly targets ULK1. EBV-miR-BART2-3p attenuated endogenous protein expression levels of some autophagy-related genes. MiR-BART2-3p could thus be involved in the regulation of autophagy. Most important, our research indicates that miR-BART2-3p targets ULK1, resulting in downregulation of epithelial-mesenchymal transformation (EMT) -associated marker proteins and reducing EMT and cell migration. Our study shows that modulation of ULK1 is the likely mechanism by which miR-BART2-3p participates in the regulation of autophagy and cancer cell migration.
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Affiliation(s)
- Duo Shi
- Department of Pathogeny Biology, School of Basic Medicine, Qingdao University, Qingdao, 266071, China
| | - Yan Zhang
- Department of Pathogeny Biology, School of Basic Medicine, Qingdao University, Qingdao, 266071, China; Department of Clinical Laboratory, Zibo Central Hospital, ZiBo, 255000, China
| | - Tao Mao
- Department of Gastroenterology, The Affiliated Hospital of Qingdao University, Qingdao, 266003, China
| | - Dandan Liu
- Department of Pathogeny Biology, School of Basic Medicine, Qingdao University, Qingdao, 266071, China
| | - Wen Liu
- Department of Pathogeny Biology, School of Basic Medicine, Qingdao University, Qingdao, 266071, China
| | - Bing Luo
- Department of Pathogeny Biology, School of Basic Medicine, Qingdao University, Qingdao, 266071, China.
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Abstract
Antigen recognition by the B cell receptor (BCR) is a physiological trigger for reactivation of Epstein-Barr virus (EBV) and can be recapitulated in vitro by cross-linking of surface immunoglobulins. Previously, we identified a subset of EBV microRNAs (miRNAs) that attenuate BCR signal transduction and subsequently dampen lytic reactivation in B cells. The roles of host miRNAs in the EBV lytic cycle are not completely understood. Here, we profiled the small RNAs in reactivated Burkitt lymphoma cells and identified several miRNAs, such as miR-141, that are induced upon BCR cross-linking. Notably, EBV encodes a viral miRNA, miR-BART9, with sequence homology to miR-141. To better understand the functions of these two miRNAs, we examined their molecular targets and experimentally validated multiple candidates commonly regulated by both miRNAs. Targets included B cell transcription factors and known regulators of EBV immediate-early genes, leading us to hypothesize that these miRNAs modulate kinetics of the lytic cascade in B cells. Through functional assays, we identified roles for miR-141 and EBV miR-BART9 and one specific target, FOXO3, in progression of the lytic cycle. Our data support a model whereby EBV exploits BCR-responsive miR-141 and further mimics activity of this miRNA family via a viral miRNA to promote productive lytic replication. IMPORTANCE EBV is a human pathogen associated with several malignancies. A key aspect of lifelong virus persistence is the ability to switch between latent and lytic replication modes. The mechanisms governing latency, reactivation, and progression of the lytic cycle are only partly understood. This study reveals that specific miRNAs can act to support the EBV lytic phase following BCR-mediated reactivation triggers. Furthermore, this study identifies a role for FOXO3, commonly suppressed by both host and viral miRNAs, in modulating progression of the EBV lytic cycle.
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11
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Bouvet M, Voigt S, Tagawa T, Albanese M, Chen YFA, Chen Y, Fachko DN, Pich D, Göbel C, Skalsky RL, Hammerschmidt W. Multiple Viral microRNAs Regulate Interferon Release and Signaling Early during Infection with Epstein-Barr Virus. mBio 2021; 12:e03440-20. [PMID: 33785626 PMCID: PMC8092300 DOI: 10.1128/mbio.03440-20] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 02/18/2021] [Indexed: 12/15/2022] Open
Abstract
Epstein-Barr virus (EBV), a human herpesvirus, encodes 44 microRNAs (miRNAs), which regulate many genes with various functions in EBV-infected cells. Multiple target genes of the EBV miRNAs have been identified, some of which play important roles in adaptive antiviral immune responses. Using EBV mutant derivatives, we identified additional roles of viral miRNAs in governing versatile type I interferon (IFN) responses upon infection of human primary mature B cells. We also found that Epstein-Barr virus-encoded small RNAs (EBERs) and LF2, viral genes with previously reported functions in inducing or regulating IFN-I pathways, had negligible or even contrary effects on secreted IFN-α in our model. Data mining and Ago PAR-CLIP experiments uncovered more than a dozen previously uncharacterized, direct cellular targets of EBV miRNA associated with type I IFN pathways. We also identified indirect targets of EBV miRNAs in B cells, such as TRL7 and TLR9, in the prelatent phase of infection. The presence of epigenetically naive, non-CpG methylated viral DNA was essential to induce IFN-α secretion during EBV infection in a TLR9-dependent manner. In a newly established fusion assay, we verified that EBV virions enter a subset of plasmacytoid dendritic cells (pDCs) and determined that these infected pDCs are the primary producers of IFN-α in EBV-infected peripheral blood mononuclear cells. Our findings document that many EBV-encoded miRNAs regulate type I IFN response in newly EBV infected primary human B cells in the prelatent phase of infection and dampen the acute release of IFN-α in pDCs upon their encounter with EBV.IMPORTANCE Acute antiviral functions of all nucleated cells rely on type I interferon (IFN-I) pathways triggered upon viral infection. Host responses encompass the sensing of incoming viruses, the activation of specific transcription factors that induce the transcription of IFN-I genes, the secretion of different IFN-I types and their recognition by the heterodimeric IFN-α/β receptor, the subsequent activation of JAK/STAT signaling pathways, and, finally, the transcription of many IFN-stimulated genes (ISGs). In sum, these cellular functions establish a so-called antiviral state in infected and neighboring cells. To counteract these cellular defense mechanisms, viruses have evolved diverse strategies and encode gene products that target antiviral responses. Among such immune-evasive factors are viral microRNAs (miRNAs) that can interfere with host gene expression. We discovered that multiple miRNAs of Epstein-Barr virus (EBV) control over a dozen cellular genes that contribute to the antiviral states of immune cells, specifically B cells and plasmacytoid dendritic cells (pDCs). We identified the viral DNA genome as the activator of IFN-α and question the role of abundant EBV EBERs, that, contrary to previous reports, do not have an apparent inducing function in the IFN-I pathway early after infection.
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Affiliation(s)
- Mickaël Bouvet
- Research Unit Gene Vectors, Helmholtz Zentrum München, German Research Center for Environmental Health and German Center for Infection Research (DZIF), Partner site Munich, Munich, Germany
| | - Stefanie Voigt
- Research Unit Gene Vectors, Helmholtz Zentrum München, German Research Center for Environmental Health and German Center for Infection Research (DZIF), Partner site Munich, Munich, Germany
| | - Takanobu Tagawa
- Research Unit Gene Vectors, Helmholtz Zentrum München, German Research Center for Environmental Health and German Center for Infection Research (DZIF), Partner site Munich, Munich, Germany
| | - Manuel Albanese
- Research Unit Gene Vectors, Helmholtz Zentrum München, German Research Center for Environmental Health and German Center for Infection Research (DZIF), Partner site Munich, Munich, Germany
| | - Yen-Fu Adam Chen
- Research Unit Gene Vectors, Helmholtz Zentrum München, German Research Center for Environmental Health and German Center for Infection Research (DZIF), Partner site Munich, Munich, Germany
| | - Yan Chen
- Vaccine and Gene Therapy Institute, Oregon Health & Science University, Beaverton, Oregon, USA
| | - Devin N Fachko
- Vaccine and Gene Therapy Institute, Oregon Health & Science University, Beaverton, Oregon, USA
| | - Dagmar Pich
- Research Unit Gene Vectors, Helmholtz Zentrum München, German Research Center for Environmental Health and German Center for Infection Research (DZIF), Partner site Munich, Munich, Germany
| | - Christine Göbel
- Research Unit Gene Vectors, Helmholtz Zentrum München, German Research Center for Environmental Health and German Center for Infection Research (DZIF), Partner site Munich, Munich, Germany
| | - Rebecca L Skalsky
- Vaccine and Gene Therapy Institute, Oregon Health & Science University, Beaverton, Oregon, USA
| | - Wolfgang Hammerschmidt
- Research Unit Gene Vectors, Helmholtz Zentrum München, German Research Center for Environmental Health and German Center for Infection Research (DZIF), Partner site Munich, Munich, Germany
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12
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Ahmad I, Valverde A, Siddiqui H, Schaller S, Naqvi AR. Viral MicroRNAs: Interfering the Interferon Signaling. Curr Pharm Des 2020; 26:446-454. [PMID: 31924149 DOI: 10.2174/1381612826666200109181238] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 12/22/2019] [Indexed: 12/23/2022]
Abstract
Interferons are secreted cytokines with potent antiviral, antitumor and immunomodulatory functions. As the first line of defense against viruses, this pathway restricts virus infection and spread. On the contrary, viruses have evolved ingenious strategies to evade host immune responses including the interferon pathway. Multiple families of viruses, in particular, DNA viruses, encode microRNA (miR) that are small, non-protein coding, regulatory RNAs. Virus-derived miRNAs (v-miR) function by targeting host and virus-encoded transcripts and are critical in shaping host-pathogen interaction. The role of v-miRs in viral pathogenesis is emerging as demonstrated by their function in subverting host defense mechanisms and regulating fundamental biological processes such as cell survival, proliferation, modulation of viral life-cycle phase. In this review, we will discuss the role of v-miRs in the suppression of host genes involved in the viral nucleic acid detection, JAK-STAT pathway, and cytokine-mediated antiviral gene activation to favor viral replication and persistence. This information has yielded new insights into our understanding of how v-miRs promote viral evasion of host immunity and likely provide novel antiviral therapeutic targets.
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Affiliation(s)
- Imran Ahmad
- Mucosal Immunology Lab, College of Dentistry, University of Illinois at Chicago, Chicago, Illinois, IL 60612, United States
| | - Araceli Valverde
- Mucosal Immunology Lab, College of Dentistry, University of Illinois at Chicago, Chicago, Illinois, IL 60612, United States
| | - Hasan Siddiqui
- Mucosal Immunology Lab, College of Dentistry, University of Illinois at Chicago, Chicago, Illinois, IL 60612, United States
| | - Samantha Schaller
- Mucosal Immunology Lab, College of Dentistry, University of Illinois at Chicago, Chicago, Illinois, IL 60612, United States
| | - Afsar R Naqvi
- Mucosal Immunology Lab, College of Dentistry, University of Illinois at Chicago, Chicago, Illinois, IL 60612, United States
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13
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Tagawa T, Serquiña A, Kook I, Ziegelbauer J. Viral non-coding RNAs: Stealth strategies in the tug-of-war between humans and herpesviruses. Semin Cell Dev Biol 2020; 111:135-147. [PMID: 32631785 DOI: 10.1016/j.semcdb.2020.06.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 06/20/2020] [Accepted: 06/24/2020] [Indexed: 12/23/2022]
Abstract
Oncogenic DNA viruses establish lifelong infections in humans, and they cause cancers, often in immunocompromised patients, despite anti-viral immune surveillance targeted against viral antigens. High-throughput sequencing techniques allowed the field to identify novel viral non-coding RNAs (ncRNAs). ncRNAs are ideal factors for DNA viruses to exploit; they are non-immunogenic to T cells, thus viral ncRNAs can manipulate host cells without evoking adaptive immune responses. Viral ncRNAs may still trigger the host innate immune response, but many viruses encode decoys/inhibitors to counter-act and evade recognition. In addition, ncRNAs can be secreted to the extracellular space and influence adjacent cells to create a pro-viral microenvironment. In this review, we present recent progress in understanding interactions between oncoviruses and ncRNAs including small and long ncRNAs, microRNAs, and recently identified viral circular RNAs. In addition, potential clinical applications for ncRNA will be discussed. Extracellular ncRNAs are suggested to be diagnostic and prognostic biomarkers and, with the realization of the importance of viral ncRNAs in tumorigenesis, approaches to target critical viral ncRNAs are emerging. Further understanding of viral utilization of ncRNAs will advance anti-viral therapeutics beyond conventional medication and vaccination.
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Affiliation(s)
- Takanobu Tagawa
- HIV and AIDS Malignancy Branch, National Cancer Institute, Bethesda, Maryland 20892, United States
| | - Anna Serquiña
- HIV and AIDS Malignancy Branch, National Cancer Institute, Bethesda, Maryland 20892, United States
| | - Insun Kook
- HIV and AIDS Malignancy Branch, National Cancer Institute, Bethesda, Maryland 20892, United States
| | - Joseph Ziegelbauer
- HIV and AIDS Malignancy Branch, National Cancer Institute, Bethesda, Maryland 20892, United States.
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14
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Heidari M, Zhang L, Zhang H. MicroRNA profiling in the bursae of Marek's disease virus-infected resistant and susceptible chicken lines. Genomics 2020; 112:2564-2571. [PMID: 32059995 DOI: 10.1016/j.ygeno.2020.02.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 01/14/2020] [Accepted: 02/10/2020] [Indexed: 12/16/2022]
Abstract
Marek's disease (MD) is a lymphoproliferative disease of domestic chickens caused by a cell-associated oncogenic alpha-herpesvirus, Marek's disease virus (MDV). Clinical signs of MD include bursal/thymic atrophy, neurologic disorders, and T cell lymphomas. MiRNAs play key roles in regulation of gene expression by targeting translational suppression or mRNA degradation. MDV encodes miRNAs that are associated with viral pathogenicity and oncogenesis. In this study, we performed miRNA sequencing in the bursal tissues, non-tumorous but viral-induced atrophied lymphoid organ, from control and infected MD-resistant and susceptible chickens at 21 days post infection. In addition to some known miRNAs, a minimum of 300 novel miRNAs were identified in each group that mapped to the chicken genome with no sequence homology to existing miRNAs in chicken miRbase. Comparative analysis identified 54 deferentially expressed miRNAs between the chicken lines that might shed light on underlying mechanism of bursal atrophy and resistance or susceptibility to MD.
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Affiliation(s)
- Mohammad Heidari
- Avian Disease and Oncology Laboratory, Agriculture Research Service, United States Department of Agriculture, East Lansing, MI, USA.
| | - Lei Zhang
- Institute of Special Wild Economic Animal and Plant Science, Chinese Academy of Agricultural Sciences, No 4899, Jv Ye Street, Changchun, Jilin 130112, China
| | - Huanmin Zhang
- Avian Disease and Oncology Laboratory, Agriculture Research Service, United States Department of Agriculture, East Lansing, MI, USA
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15
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Münz C. Latency and lytic replication in Epstein-Barr virus-associated oncogenesis. Nat Rev Microbiol 2019; 17:691-700. [PMID: 31477887 DOI: 10.1038/s41579-019-0249-7] [Citation(s) in RCA: 227] [Impact Index Per Article: 45.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/18/2019] [Indexed: 12/19/2022]
Abstract
Epstein-Barr virus (EBV) was the first tumour virus identified in humans. The virus is primarily associated with lymphomas and epithelial cell cancers. These tumours express latent EBV antigens and the oncogenic potential of individual latent EBV proteins has been extensively explored. Nevertheless, it was presumed that the pro-proliferative and anti-apoptotic functions of these oncogenes allow the virus to persist in humans; however, recent evidence suggests that cellular transformation is not required for virus maintenance. Vice versa, lytic EBV replication was assumed to destroy latently infected cells and thereby inhibit tumorigenesis, but at least the initiation of the lytic cycle has now been shown to support EBV-driven malignancies. In addition to these changes in the roles of latent and lytic EBV proteins during tumorigenesis, the function of non-coding RNAs has become clearer, suggesting that they might mainly mediate immune escape rather than cellular transformation. In this Review, these recent findings will be discussed with respect to the role of EBV-encoded oncogenes in viral persistence and the contributions of lytic replication as well as non-coding RNAs in virus-driven tumour formation. Accordingly, early lytic EBV antigens and attenuated viruses without oncogenes and microRNAs could be harnessed for immunotherapies and vaccination.
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Affiliation(s)
- Christian Münz
- Viral Immunobiology, Institute of Experimental Immunology, University of Zürich, Zürich, Switzerland.
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16
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Bullard WL, Kara M, Gay LA, Sethuraman S, Wang Y, Nirmalan S, Esemenli A, Feswick A, Hoffman BA, Renne R, Tibbetts SA. Identification of murine gammaherpesvirus 68 miRNA-mRNA hybrids reveals miRNA target conservation among gammaherpesviruses including host translation and protein modification machinery. PLoS Pathog 2019; 15:e1007843. [PMID: 31393953 PMCID: PMC6687095 DOI: 10.1371/journal.ppat.1007843] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 05/15/2019] [Indexed: 02/07/2023] Open
Abstract
Gammaherpesviruses, including the human pathogens Epstein-Barr virus (EBV) and Kaposi’s sarcoma-associated herpesvirus (KSHV), establish lifelong latent infection in B cells and are associated with a variety of tumors. In addition to protein coding genes, these viruses encode numerous microRNAs (miRNAs) within their genomes. While putative host targets of EBV and KSHV miRNAs have been previously identified, the specific functions of these miRNAs during in vivo infection are largely unknown. Murine gammaherpesvirus 68 (MHV68) is a natural pathogen of rodents that is genetically related to both EBV and KSHV, and thus serves as an excellent model for the study of EBV and KSHV genetic elements such as miRNAs in the context of infection and disease. However, the specific targets of MHV68 miRNAs remain completely unknown. Using a technique known as qCLASH (quick crosslinking, ligation, and sequencing of hybrids), we have now identified thousands of Ago-associated, direct miRNA-mRNA interactions during lytic infection, latent infection and reactivation from latency. Validating this approach, detailed molecular analyses of specific interactions demonstrated repression of numerous host mRNA targets of MHV68 miRNAs, including Arid1a, Ctsl, Ifitm3 and Phc3. Notably, of the 1,505 MHV68 miRNA-host mRNA targets identified in B cells, 86% were shared with either EBV or KSHV, and 64% were shared among all three viruses, demonstrating significant conservation of gammaherpesvirus miRNA targeting. Pathway analysis of MHV68 miRNA targets further revealed enrichment of cellular pathways involved in protein synthesis and protein modification, including eIF2 Signaling, mTOR signaling and protein ubiquitination, pathways also enriched for targets of EBV and KSHV miRNAs. These findings provide substantial new information about specific targets of MHV68 miRNAs and shed important light on likely conserved functions of gammaherpesvirus miRNAs. Gammaherpesviruses, including the human pathogens Epstein-Barr virus (EBV) and Kaposi’s sarcoma-associated herpesvirus (KSHV), establish lifelong infections and are associated with a variety of tumors. These viruses encode numerous molecules called microRNAs (miRNAs) within their genomes, which target and suppress the products of specific genes within infected host cells. However, the function of these miRNAs during in vivo infection is largely unknown. Murine gammaherpesvirus 68 (MHV68) is a natural pathogen of rodents that is genetically related to both EBV and KSHV, and thus serves as an excellent model for the study of EBV and KSHV. Here, we describe the identification and validation of thousands of new MHV68 miRNA targets. Notably, 86% of the MHV68 miRNA targets identified were shared with either EBV or KSHV, and 64% were shared among all three viruses. Further analyses revealed enrichment of cellular pathways involved in protein synthesis and protein modification, including pathways also enriched for targets of EBV and KSHV miRNAs. These findings provide substantial new information about specific targets of MHV68 miRNAs and shed important light on likely conserved functions of gammaherpesvirus miRNAs.
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Affiliation(s)
- Whitney L. Bullard
- Dept. of Molecular Genetics and Microbiology, UF Health Cancer Center, University of Florida, Gainesville, Florida, United States of America
| | - Mehmet Kara
- Dept. of Molecular Genetics and Microbiology, UF Health Cancer Center, University of Florida, Gainesville, Florida, United States of America
| | - Lauren A. Gay
- Dept. of Molecular Genetics and Microbiology, UF Health Cancer Center, University of Florida, Gainesville, Florida, United States of America
| | - Sunantha Sethuraman
- Dept. of Molecular Genetics and Microbiology, UF Health Cancer Center, University of Florida, Gainesville, Florida, United States of America
| | - Yiping Wang
- Dept. of Molecular Genetics and Microbiology, UF Health Cancer Center, University of Florida, Gainesville, Florida, United States of America
| | - Shreya Nirmalan
- Dept. of Molecular Genetics and Microbiology, UF Health Cancer Center, University of Florida, Gainesville, Florida, United States of America
| | - Alim Esemenli
- Dept. of Molecular Genetics and Microbiology, UF Health Cancer Center, University of Florida, Gainesville, Florida, United States of America
| | - April Feswick
- Dept. of Molecular Genetics and Microbiology, UF Health Cancer Center, University of Florida, Gainesville, Florida, United States of America
| | - Brett A. Hoffman
- Dept. of Molecular Genetics and Microbiology, UF Health Cancer Center, University of Florida, Gainesville, Florida, United States of America
| | - Rolf Renne
- Dept. of Molecular Genetics and Microbiology, UF Health Cancer Center, University of Florida, Gainesville, Florida, United States of America
| | - Scott A. Tibbetts
- Dept. of Molecular Genetics and Microbiology, UF Health Cancer Center, University of Florida, Gainesville, Florida, United States of America
- * E-mail:
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17
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Hancock MH, Skalsky RL. Roles of Non-coding RNAs During Herpesvirus Infection. Curr Top Microbiol Immunol 2019; 419:243-280. [PMID: 28674945 DOI: 10.1007/82_2017_31] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Non-coding RNAs (ncRNAs) play essential roles in multiple aspects of the life cycles of herpesviruses and contribute to lifelong persistence of herpesviruses within their respective hosts. In this chapter, we discuss the types of ncRNAs produced by the different herpesvirus families during infection, some of the cellular ncRNAs manipulated by these viruses, and the overall contributions of ncRNAs to the viral life cycle, influence on the host environment, and pathogenesis.
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Affiliation(s)
- Meaghan H Hancock
- Vaccine and Gene Therapy Institute at Oregon Health and Science University, Beaverton, OR, USA
| | - Rebecca L Skalsky
- Vaccine and Gene Therapy Institute at Oregon Health and Science University, Beaverton, OR, USA.
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18
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Ungerleider NA, Jain V, Wang Y, Maness NJ, Blair RV, Alvarez X, Midkiff C, Kolson D, Bai S, Roberts C, Moss WN, Wang X, Serfecz J, Seddon M, Lehman T, Ma T, Dong Y, Renne R, Tibbetts SA, Flemington EK. Comparative Analysis of Gammaherpesvirus Circular RNA Repertoires: Conserved and Unique Viral Circular RNAs. J Virol 2019; 93:e01952-18. [PMID: 30567979 PMCID: PMC6401440 DOI: 10.1128/jvi.01952-18] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 12/11/2018] [Indexed: 01/02/2023] Open
Abstract
Recent studies have identified circular RNAs (circRNAs) expressed from the Epstein-Barr virus (EBV) and Kaposi's sarcoma herpesvirus (KSHV) human DNA tumor viruses. To gain initial insights into the potential relevance of EBV circRNAs in virus biology and disease, we assessed the circRNAome of the interspecies homologue rhesus macaque lymphocryptovirus (rLCV) in a naturally occurring lymphoma from a simian immunodeficiency virus (SIV)-infected rhesus macaque. This analysis revealed rLCV orthologues of the latency-associated EBV circular RNAs circRPMS1_E4_E3a and circEBNA_U. Also identified in two samples displaying unusually high lytic gene expression was a novel rLCV circRNA that contains both conserved and rLCV-specific RPMS1 exons and whose backsplice junctions flank an rLCV lytic origin of replication (OriLyt). Analysis of a lytic infection model for the murid herpesvirus 68 (MHV68) rhadinovirus identified a cluster of circRNAs near an MHV68 lytic origin of replication, with the most abundant of these, circM11_ORF69, spanning the OriLyt. Lastly, analysis of KSHV latency and reactivation models revealed the latency associated circRNA originating from the vIRF4 gene as the predominant viral circRNA. Together, the results of this study broaden our appreciation for circRNA repertoires in the Lymphocryptovirus and Rhadinovirus genera of gammaherpesviruses and provide evolutionary support for viral circRNA functions in latency and viral replication.IMPORTANCE Infection with oncogenic gammaherpesviruses leads to long-term viral persistence through a dynamic interplay between the virus and the host immune system. Critical for remodeling of the host cell environment after the immune responses are viral noncoding RNAs that modulate host signaling pathways without attracting adaptive immune recognition. Despite the importance of noncoding RNAs in persistent infection, the circRNA class of noncoding RNAs has only recently been identified in gammaherpesviruses. Accordingly, their roles in virus infection and associated oncogenesis are unknown. Here we report evolutionary conservation of EBV-encoded circRNAs determined by assessing the circRNAome in rLCV-infected lymphomas from an SIV-infected rhesus macaque, and we report latent and lytic circRNAs from KSHV and MHV68. These experiments demonstrate utilization of the circular RNA class of RNAs across 4 members of the gammaherpesvirus subfamily, and they identify orthologues and potential homoplastic circRNAs, implying conserved circRNA functions in virus biology and associated malignancies.
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Affiliation(s)
- Nathan A Ungerleider
- Department of Pathology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, Louisiana, USA
| | - Vaibhav Jain
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, Florida, USA
| | - Yiping Wang
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, USA
| | - Nicholas J Maness
- Department of Microbiology and Immunology, Tulane Regional Primate Center, Covington, Louisiana, USA
| | - Robert V Blair
- Division of Comparative Pathology, Tulane Regional Primate Center, Covington, Louisiana, USA
| | - Xavier Alvarez
- Division of Comparative Pathology, Tulane Regional Primate Center, Covington, Louisiana, USA
| | - Cecily Midkiff
- Division of Comparative Pathology, Tulane Regional Primate Center, Covington, Louisiana, USA
| | - Dennis Kolson
- Division of Comparative Pathology, Tulane Regional Primate Center, Covington, Louisiana, USA
| | - Shanshan Bai
- Department of Neurology, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Claire Roberts
- Department of Pathology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, Louisiana, USA
| | - Walter N Moss
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa, USA
| | - Xia Wang
- Department of Pathology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, Louisiana, USA
| | - Jacqueline Serfecz
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, USA
| | | | | | - Tianfang Ma
- Department of Structural and Cellular Biology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, Louisiana, USA
| | - Yan Dong
- Department of Structural and Cellular Biology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, Louisiana, USA
| | - Rolf Renne
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, Florida, USA
| | - Scott A Tibbetts
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, Florida, USA
| | - Erik K Flemington
- Department of Pathology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, Louisiana, USA
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19
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Chen Y, Fachko D, Ivanov NS, Skinner CM, Skalsky RL. Epstein-Barr virus microRNAs regulate B cell receptor signal transduction and lytic reactivation. PLoS Pathog 2019; 15:e1007535. [PMID: 30615681 PMCID: PMC6336353 DOI: 10.1371/journal.ppat.1007535] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 01/17/2019] [Accepted: 12/17/2018] [Indexed: 12/15/2022] Open
Abstract
MicroRNAs (miRNAs) are post-transcriptional regulatory RNAs that can modulate cell signaling and play key roles in cell state transitions. Epstein-Barr virus (EBV) expresses >40 viral miRNAs that manipulate both viral and cellular gene expression patterns and contribute to reprogramming of the host environment during infection. Here, we identified a subset of EBV miRNAs that desensitize cells to B cell receptor (BCR) stimuli, and attenuate the downstream activation of NF-kappaB or AP1-dependent transcription. Bioinformatics and pathway analysis of Ago PAR-CLIP datasets identified multiple EBV miRNA targets related to BCR signal transduction, including GRB2, SOS1, MALT1, RAC1, and INPP5D, which we validated in reporter assays. BCR signaling is critical for B cell activation, proliferation, and differentiation, and for EBV, is linked to reactivation. In functional assays, we demonstrate that EBV miR-BHRF1-2-5p contributes to the growth of latently infected B cells through GRB2 regulation. We further determined that activities of EBV miR-BHRF1-2-5p, EBV miR-BART2-5p, and a cellular miRNA, miR-17-5p, directly regulate virus reactivation triggered by BCR engagement. Our findings provide mechanistic insight into some of the key miRNA interactions impacting the proliferation of latently infected B cells and importantly, governing the latent to lytic switch.
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Affiliation(s)
- Yan Chen
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Beaverton, Oregon, United States of America
| | - Devin Fachko
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Beaverton, Oregon, United States of America
| | - Nikita S. Ivanov
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Beaverton, Oregon, United States of America
| | - Camille M. Skinner
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Beaverton, Oregon, United States of America
| | - Rebecca L. Skalsky
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Beaverton, Oregon, United States of America
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20
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HCMV miRNA Targets Reveal Important Cellular Pathways for Viral Replication, Latency, and Reactivation. Noncoding RNA 2018; 4:ncrna4040029. [PMID: 30360396 PMCID: PMC6315856 DOI: 10.3390/ncrna4040029] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 10/12/2018] [Accepted: 10/17/2018] [Indexed: 02/06/2023] Open
Abstract
It is now well appreciated that microRNAs (miRNAs) play a critical role in the lifecycles of many herpes viruses. The human cytomegalovirus (HCMV) replication cycle varies significantly depending on the cell type infected, with lytic replication occurring in fully-differentiated cells such as fibroblasts, endothelial cells, or macrophages, and latent infection occurring in less-differentiated CD14+ monocytes and CD34+ hematopoietic progenitor cells where viral gene expression is severely diminished and progeny virus is not produced. Given their non-immunogenic nature and their capacity to target numerous cellular and viral transcripts, miRNAs represent a particularly advantageous means for HCMV to manipulate viral gene expression and cellular signaling pathways during lytic and latent infection. This review will focus on our current knowledge of HCMV miRNA viral and cellular targets, and discuss their importance in lytic and latent infection, highlight the challenges of studying HCMV miRNAs, and describe how viral miRNAs can help us to better understand the cellular processes involved in HCMV latency.
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21
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Wu J, Yang J, Ding J, Guo X, Zhu XQ, Zheng Y. Exosomes in virus-associated cancer. Cancer Lett 2018; 438:44-51. [PMID: 30219505 DOI: 10.1016/j.canlet.2018.09.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 08/30/2018] [Accepted: 09/10/2018] [Indexed: 12/13/2022]
Abstract
Exosomes are phospholipid bilayer membrane-enclosed vesicles in a size from 30 to 150 nm, carrying a variety of active components, such as proteins, mRNA and miRNAs, and are involved in intercellular communication. Exosomes are released by almost all living cells and detected in various biological fluids. Viruses especially oncogenic viruses have been reported to influence the formation of virus-associated cancer through reshaping the tumor microenvironment via exosomes. In this review, a role of exosomes released by oncogenic virus-infected cells in promoting or inhibiting cancer formation is outlined. Moreover, the prospects and challenges of exosome applications in cancer therapies are critically discussed.
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Affiliation(s)
- Jin'en Wu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, CAAS, Lanzhou, 730046, China
| | - Jing Yang
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, CAAS, Lanzhou, 730046, China
| | - Juntao Ding
- College of Life Science and Technology, Xinjiang University, Urumqi, 830046, China
| | - Xiaola Guo
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, CAAS, Lanzhou, 730046, China
| | - Xing-Quan Zhu
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, CAAS, Lanzhou, 730046, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University College of Veterinary Medicine, Yangzhou, 225009, China
| | - Yadong Zheng
- State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, CAAS, Lanzhou, 730046, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University College of Veterinary Medicine, Yangzhou, 225009, China.
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22
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Ungerleider N, Concha M, Lin Z, Roberts C, Wang X, Cao S, Baddoo M, Moss WN, Yu Y, Seddon M, Lehman T, Tibbetts S, Renne R, Dong Y, Flemington EK. The Epstein Barr virus circRNAome. PLoS Pathog 2018; 14:e1007206. [PMID: 30080890 PMCID: PMC6095625 DOI: 10.1371/journal.ppat.1007206] [Citation(s) in RCA: 100] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 08/16/2018] [Accepted: 07/11/2018] [Indexed: 11/18/2022] Open
Abstract
Our appreciation for the extent of Epstein Barr virus (EBV) transcriptome complexity continues to grow through findings of EBV encoded microRNAs, new long non-coding RNAs as well as the more recent discovery of over a hundred new polyadenylated lytic transcripts. Here we report an additional layer to the EBV transcriptome through the identification of a repertoire of latent and lytic viral circular RNAs. Utilizing RNase R-sequencing with cell models representing latency types I, II, and III, we identified EBV encoded circular RNAs expressed from the latency Cp promoter involving backsplicing from the W1 and W2 exons to the C1 exon, from the EBNA BamHI U fragment exon, and from the latency long non-coding RPMS1 locus. In addition, we identified circular RNAs expressed during reactivation including backsplicing from exon 8 to exon 2 of the LMP2 gene and a highly expressed circular RNA derived from intra-exonic backsplicing within the BHLF1 gene. While expression of most of these circular RNAs was found to depend on the EBV transcriptional program utilized and the transcription levels of the associated loci, expression of LMP2 exon 8 to exon 2 circular RNA was found to be cell model specific. Altogether we identified over 30 unique EBV circRNAs candidates and we validated and determined the structural features, expression profiles and nuclear/cytoplasmic distributions of several predominant and notable viral circRNAs. Further, we show that two of the EBV circular RNAs derived from the RPMS1 locus are detected in EBV positive clinical stomach cancer specimens. This study increases the known EBV latency and lytic transcriptome repertoires to include viral circular RNAs and it provides an essential foundation and resource for investigations into the functions and roles of this new class of EBV transcripts in EBV biology and diseases. Our understanding of the extent of EBV transcriptome complexity has recently come to light with discoveries of viral microRNAs, snoRNAs, and a diverse set of transcript isoforms expressed during reactivation. While EBV utilizes distinct transcriptional programs during it’s normal infection cycle, the latency programs are critical drivers of EBV associated oncogenesis where they activate oncogenic pathways without killing the cell via lytic viral replication. Further, pathogenic latency programs typically express minimal levels of viral protein coding genes and instead rely on non-coding RNA mechanisms to alter the host cell environment. The utilization of non-coding RNAs in these settings is presumably an effort to minimize infected cell killing by the immune system through adaptive immune responses. Using tissue culture models representing the spectrum of EBV transcriptional states that occur in vivo, we report here that EBV expresses the circular class of predominantly non-coding RNAs. This stands to reveal a previously unknown set of players in EBV associated biology and disease. The findings reported here set a key platform from which future functional and potentially clinical related studies can be carried out to bring the initial findings from discovery to a new understanding of EBV biology and disease.
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Affiliation(s)
- Nathan Ungerleider
- Department of Pathology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, LA, United States of America
| | - Monica Concha
- Department of Pathology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, LA, United States of America
| | - Zhen Lin
- Department of Pathology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, LA, United States of America
| | - Claire Roberts
- Department of Pathology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, LA, United States of America
| | - Xia Wang
- Department of Pathology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, LA, United States of America
| | - Subing Cao
- Department of Structural and Cellular Biology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, LA, United States of America
| | - Melody Baddoo
- Department of Pathology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, LA, United States of America
| | - Walter N. Moss
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, United States of America
| | - Yi Yu
- Department of Pathology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, LA, United States of America
| | | | - Terri Lehman
- Reprocell USA, Beltsville, MD, United States of America
| | - Scott Tibbetts
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, FL, United States of America
| | - Rolf Renne
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, United States of America
| | - Yan Dong
- Department of Structural and Cellular Biology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, LA, United States of America
| | - Erik K. Flemington
- Department of Pathology, Tulane University School of Medicine, Tulane Cancer Center, New Orleans, LA, United States of America
- * E-mail:
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23
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Fan C, Tang Y, Wang J, Xiong F, Guo C, Wang Y, Xiang B, Zhou M, Li X, Wu X, Li Y, Li X, Li G, Xiong W, Zeng Z. The emerging role of Epstein-Barr virus encoded microRNAs in nasopharyngeal carcinoma. J Cancer 2018; 9:2852-2864. [PMID: 30123354 PMCID: PMC6096363 DOI: 10.7150/jca.25460] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 06/16/2018] [Indexed: 12/24/2022] Open
Abstract
Epstein-Barr virus (EBV) is an oncogenic herpes virus that is closely associated with the initiation and development of nasopharyngeal carcinoma (NPC), lymphoma and other malignant tumors. EBV encodes 44 mature miRNAs that regulate viral and host cell gene expression and plays a variety of roles in biological functions and the development of cancer. In this review, we summarized the biological functions and molecular mechanisms of Epstein-Barr virus-encoded microRNAs (EBV miRNAs) in tumor immune evasion, proliferation, anti-apoptosis, invasion, metastasis and as a potential biomarker for NPC diagnosis and prognosis. The knowledge generated by EBV miRNAs can be used for EBV miRNA-based precision cancer treatments in the near future.
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Affiliation(s)
- Chunmei Fan
- Hunan Key Laboratory of Translational Radiation Oncology, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, China.,The Key Laboratory of Carcinogenesis of the Chinese Ministry of Health, Cancer Research Institute and School of Basic Medical Science,, Central South University, Changsha, Hunan, China.,The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yanyan Tang
- Hunan Key Laboratory of Translational Radiation Oncology, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, China.,The Key Laboratory of Carcinogenesis of the Chinese Ministry of Health, Cancer Research Institute and School of Basic Medical Science,, Central South University, Changsha, Hunan, China
| | - Jinpeng Wang
- The Key Laboratory of Carcinogenesis of the Chinese Ministry of Health, Cancer Research Institute and School of Basic Medical Science,, Central South University, Changsha, Hunan, China
| | - Fang Xiong
- The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Can Guo
- The Key Laboratory of Carcinogenesis of the Chinese Ministry of Health, Cancer Research Institute and School of Basic Medical Science,, Central South University, Changsha, Hunan, China
| | - Yumin Wang
- The Key Laboratory of Carcinogenesis of the Chinese Ministry of Health, Cancer Research Institute and School of Basic Medical Science,, Central South University, Changsha, Hunan, China
| | - Bo Xiang
- The Key Laboratory of Carcinogenesis of the Chinese Ministry of Health, Cancer Research Institute and School of Basic Medical Science,, Central South University, Changsha, Hunan, China
| | - Ming Zhou
- The Key Laboratory of Carcinogenesis of the Chinese Ministry of Health, Cancer Research Institute and School of Basic Medical Science,, Central South University, Changsha, Hunan, China
| | - Xiayu Li
- The Key Laboratory of Carcinogenesis of the Chinese Ministry of Health, Cancer Research Institute and School of Basic Medical Science,, Central South University, Changsha, Hunan, China.,Hunan Key Laboratory of Nonresolving Inflammation and Cancer, Disease Genome Research Center, The Third Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Xu Wu
- The Key Laboratory of Carcinogenesis of the Chinese Ministry of Health, Cancer Research Institute and School of Basic Medical Science,, Central South University, Changsha, Hunan, China.,Department of Chemistry, University of North Dakota, Grand Forks, North Dakota, USA
| | - Yong Li
- The Key Laboratory of Carcinogenesis of the Chinese Ministry of Health, Cancer Research Institute and School of Basic Medical Science,, Central South University, Changsha, Hunan, China.,Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Xiaoling Li
- Hunan Key Laboratory of Translational Radiation Oncology, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, China.,The Key Laboratory of Carcinogenesis of the Chinese Ministry of Health, Cancer Research Institute and School of Basic Medical Science,, Central South University, Changsha, Hunan, China.,The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Guiyuan Li
- Hunan Key Laboratory of Translational Radiation Oncology, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, China.,The Key Laboratory of Carcinogenesis of the Chinese Ministry of Health, Cancer Research Institute and School of Basic Medical Science,, Central South University, Changsha, Hunan, China.,The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Wei Xiong
- Hunan Key Laboratory of Translational Radiation Oncology, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, China.,The Key Laboratory of Carcinogenesis of the Chinese Ministry of Health, Cancer Research Institute and School of Basic Medical Science,, Central South University, Changsha, Hunan, China.,The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Zhaoyang Zeng
- Hunan Key Laboratory of Translational Radiation Oncology, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan, China.,The Key Laboratory of Carcinogenesis of the Chinese Ministry of Health, Cancer Research Institute and School of Basic Medical Science,, Central South University, Changsha, Hunan, China.,The Key Laboratory of Carcinogenesis and Cancer Invasion of the Chinese Ministry of Education, Xiangya Hospital, Central South University, Changsha, Hunan, China
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24
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Jiang L, Wang Q, Yu J, Gowda V, Johnson G, Yang J, Kan X, Yang X. miRNAome expression profiles in the gonads of adult Melopsittacus undulatus. PeerJ 2018; 6:e4615. [PMID: 29666766 PMCID: PMC5896495 DOI: 10.7717/peerj.4615] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 03/22/2018] [Indexed: 01/11/2023] Open
Abstract
The budgerigar (Melopsittacus undulatus) is one of the most widely studied parrot species, serving as an excellent animal model for behavior and neuroscience research. Until recently, it was unknown how sexual differences in the behavior, physiology, and development of organisms are regulated by differential gene expression. MicroRNAs (miRNAs) are endogenous short non-coding RNA molecules that can post-transcriptionally regulate gene expression and play a critical role in gonadal differentiation as well as early development of animals. However, very little is known about the role gonadal miRNAs play in the early development of birds. Research on the sex-biased expression of miRNAs in avian gonads are limited, and little is known about M. undulatus. In the current study, we sequenced two small non-coding RNA libraries made from the gonads of adult male and female budgerigars using Illumina paired-end sequencing technology. We obtained 254 known and 141 novel miRNAs, and randomly validated five miRNAs. Of these, three miRNAs were differentially expressed miRNAs and 18 miRNAs involved in sexual differentiation as determined by functional analysis with GO annotation and KEGG pathway analysis. In conclusion, this work is the first report of sex-biased miRNAs expression in the budgerigar, and provides additional sequences to the avian miRNAome database which will foster further functional genomic research.
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Affiliation(s)
- Lan Jiang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China.,The Institute of Bioinformatics, College of Life Sciences, Anhui Normal University, Wuhu, China
| | - Qingqing Wang
- The Institute of Bioinformatics, College of Life Sciences, Anhui Normal University, Wuhu, China.,The Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui, Wuhu, China
| | - Jue Yu
- College of Foreign Studies, Anhui Normal University, Wuhu, China
| | - Vinita Gowda
- Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, Madhya Pradesh, India
| | - Gabriel Johnson
- Department of Botany, National Museum of Natural History, Smithsonian Institution, Washington, District of Columbia, USA
| | - Jianke Yang
- School of Basic Medicine, Wannan Medical College, Wuhu, China
| | - Xianzhao Kan
- The Institute of Bioinformatics, College of Life Sciences, Anhui Normal University, Wuhu, China.,The Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui, Wuhu, China
| | - Xiaojun Yang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
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25
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Wang M, Yu F, Wu W, Wang Y, Ding H, Qian L. Epstein-Barr virus-encoded microRNAs as regulators in host immune responses. Int J Biol Sci 2018; 14:565-576. [PMID: 29805308 PMCID: PMC5968849 DOI: 10.7150/ijbs.24562] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Accepted: 03/06/2018] [Indexed: 12/12/2022] Open
Abstract
Epstein-Barr virus (EBV) is an oncogenic virus that infects over 90% of the world's adult population. EBV can establish life-long latent infection in host due to the balance between EBV and host immune system. EBV latency is associated with various malignancies such as nasopharyngeal carcinoma, gastric carcinoma and Burkitt's lymphoma. EBV is the first human virus that has the capability to encode microRNAs (miRNAs). Remarkably, EBV-encoded miRNAs are abundantly expressed in latently-infected cells and serve important function in viral infection and pathogenesis. Increasing evidence indicates that EBV miRNAs target the host mRNAs involved in cell proliferation, apoptosis and transformation. EBV miRNAs also inhibit the expression of viral antigens, thereby enabling infected cells to escape immune recognition. Intriguingly, EBV miRNAs directly suppress host antiviral immunity by interfering with antigen presentation and immune cell activation. This review will update the current knowledge about EBV miRNAs implicated in host immune responses. An in-depth understanding of the functions of EBV miRNAs in host antiviral immunity will shed light on the EBV-host interactions and provide potential therapeutic targets for the treatment of EBV-associated malignancies.
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Affiliation(s)
- Man Wang
- Institute for Translational Medicine, Medical College of Qingdao University, Dengzhou Road 38, Qingdao 266021, China
| | - Fei Yu
- Institute for Translational Medicine, Medical College of Qingdao University, Dengzhou Road 38, Qingdao 266021, China
| | - Wei Wu
- Institute for Translational Medicine, Medical College of Qingdao University, Dengzhou Road 38, Qingdao 266021, China
| | - Yu Wang
- Institute for Translational Medicine, Medical College of Qingdao University, Dengzhou Road 38, Qingdao 266021, China
| | - Han Ding
- Institute for Translational Medicine, Medical College of Qingdao University, Dengzhou Road 38, Qingdao 266021, China
| | - Lili Qian
- Institute for Translational Medicine, Medical College of Qingdao University, Dengzhou Road 38, Qingdao 266021, China
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26
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Poling BC, Price AM, Luftig MA, Cullen BR. The Epstein-Barr virus miR-BHRF1 microRNAs regulate viral gene expression in cis. Virology 2017; 512:113-123. [PMID: 28950226 DOI: 10.1016/j.virol.2017.09.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 09/05/2017] [Accepted: 09/18/2017] [Indexed: 10/18/2022]
Abstract
The Epstein-Barr virus (EBV) miR-BHRF1 microRNA (miRNA) cluster has been shown to facilitate B-cell transformation and promote the rapid growth of the resultant lymphoblastoid cell lines (LCLs). However, we find that expression of physiological levels of the miR-BHRF1 miRNAs in LCLs transformed with a miR-BHRF1 null mutant (∆123) fails to increase their growth rate. We demonstrate that the pri-miR-BHRF1-2 and 1-3 stem-loops are present in the 3'UTR of transcripts encoding EBNA-LP and that excision of pre-miR-BHRF1-2 and 1-3 by Drosha destabilizes these mRNAs and reduces expression of the encoded protein. Therefore, mutational inactivation of pri-miR-BHRF1-2 and 1-3 in the ∆123 mutant upregulates the expression of not only EBNA-LP but also EBNA-LP-regulated mRNAs and proteins, including LMP1. We hypothesize that this overexpression causes the reduced transformation capacity of the ∆123 EBV mutant. Thus, in addition to regulating cellular mRNAs in trans, miR-BHRF1-2 and 1-3 also regulate EBNA-LP mRNA expression in cis.
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Affiliation(s)
- Brigid Chiyoko Poling
- Department of Molecular Genetics & Microbiology and Center for Virology, Duke University Medical Center, Durham, NC, USA.
| | - Alexander M Price
- Department of Molecular Genetics & Microbiology and Center for Virology, Duke University Medical Center, Durham, NC, USA.
| | - Micah A Luftig
- Department of Molecular Genetics & Microbiology and Center for Virology, Duke University Medical Center, Durham, NC, USA.
| | - Bryan R Cullen
- Department of Molecular Genetics & Microbiology and Center for Virology, Duke University Medical Center, Durham, NC, USA.
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27
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An Epstein-Barr Virus MicroRNA Blocks Interleukin-1 (IL-1) Signaling by Targeting IL-1 Receptor 1. J Virol 2017; 91:JVI.00530-17. [PMID: 28794034 DOI: 10.1128/jvi.00530-17] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 08/04/2017] [Indexed: 12/27/2022] Open
Abstract
Epstein-Barr virus (EBV) encodes >44 viral microRNAs (miRNAs) that are differentially expressed throughout infection, can be detected in Epstein-Barr virus (EBV)-positive tumors, and manipulate several biological processes, including cell proliferation, apoptosis, and immune responses. Here, we show that EBV BHRF1-2 miRNAs block NF-κB activation following treatment with proinflammatory cytokines, specifically interleukin-1β (IL-1β). Analysis of EBV PAR-CLIP miRNA targetome data sets combined with pathway analysis revealed multiple BHRF1-2 miRNA targets involved in interleukin signaling pathways. By further analyzing changes in cellular gene expression patterns, we identified the IL-1 receptor 1 (IL1R1) as a direct target of miR-BHRF1-2-5p. Targeting the IL1R1 3' untranslated region (UTR) by EBV miR-BHRF1-2-5p was confirmed using 3'-UTR luciferase reporter assays and Western blot assays. Manipulation of EBV BHRF1-2 miRNA activity in latently infected B cells altered steady-state cytokine levels and disrupted IL-1β responsiveness. These studies demonstrate functionally relevant BHRF1-2 miRNA interactions during EBV infection, which is an important step in understanding their roles in pathogenesis.IMPORTANCE IL-1 signaling plays an important role in inflammation and early activation of host innate immune responses following virus infection. Here, we demonstrate that a viral miRNA downregulates the IL-1 receptor 1 during EBV infection, which consequently alters the responsiveness of cells to IL-1 stimuli and changes the cytokine expression levels within infected cell populations. We postulate that this viral miRNA activity not only disrupts IL-1 autocrine and paracrine signaling loops that can alert effector cells to sites of infection but also provides a survival advantage by dampening excessive inflammation that may be detrimental to the infected cell.
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28
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Hancock MH, Nelson JA. Modulation of the NFκb Signalling Pathway by Human Cytomegalovirus. VIROLOGY (HYDERABAD) 2017; 1:104. [PMID: 29082387 PMCID: PMC5659363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Many viruses trigger innate and adaptive immune responses and must circumvent the negative consequences to successfully establish infection in their hosts. Human Cytomegalovirus (HCMV) is no exception, and devotes a significant portion of its coding capacity to genes involved in immune evasion. Activation of the NFκB signalling pathway by viral binding and entry results in induction of antiviral and pro-inflammatory genes that have significant negative effects on HCMV infection. However, NFκB signalling stimulates transcription from the Major Immediate Early Promoter (MIEP) and pro-inflammatory signalling is crucial for cellular differentiation and viral reactivation from latency. Accordingly, HCMV encodes proteins that act to both stimulate and inhibit the NFκB signalling pathway. In this Review we will highlight the complex interactions between HCMV and NFκB, discussing the known agonists and antagonists encoded by the virus and suggest why manipulation of the pathway may be critical for both lytic and latent infections.
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Affiliation(s)
- Meaghan H Hancock
- Corresponding author: Meaghan H. Hancock, Vaccine and Gene Therapy Institute, Oregon Health and Science University, Beaverton, Oregon, USA, Tel: 503-418-2784;
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29
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An update: Epstein-Barr virus and immune evasion via microRNA regulation. Virol Sin 2017; 32:175-187. [PMID: 28669004 PMCID: PMC6702289 DOI: 10.1007/s12250-017-3996-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Accepted: 06/12/2017] [Indexed: 12/12/2022] Open
Abstract
Epstein-Barr virus (EBV) is an oncogenic virus that ubiquitously establishes
life-long persistence in humans. To ensure its survival and maintain its B cell
transformation function, EBV has developed powerful strategies to evade host immune
responses. Emerging evidence has shown that microRNAs (miRNAs) are powerful
regulators of the maintenance of cellular homeostasis. In this review, we summarize
current progress on how EBV utilizes miRNAs for immune evasion. EBV encodes miRNAs
targeting both viral and host genes involved in the immune response. The miRNAs are
found in two gene clusters, and recent studies have demonstrated that lack of these
clusters increases the CD4+ and
CD8+ T cell response of infected cells. These reports
strongly indicate that EBV miRNAs are critical for immune evasion. In addition, EBV
is able to dysregulate the expression of a variety of host miRNAs, which influence
multiple immune-related molecules and signaling pathways. The transport via exosomes
of EBV-regulated miRNAs and viral proteins contributes to the construction and
modification of the inflammatory tumor microenvironment. During EBV immune evasion,
viral proteins, immune cells, chemokines, pro-inflammatory cytokines, and
pro-apoptosis molecules are involved. Our increasing knowledge of the role of miRNAs
in immune evasion will improve the understanding of EBV persistence and help to
develop new treatments for EBV-associated cancers and other diseases.
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30
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Assadian F, Kamel W, Laurell G, Svensson C, Punga T, Akusjärvi G. Expression profile of Epstein-Barr virus and human adenovirus small RNAs in tonsillar B and T lymphocytes. PLoS One 2017; 12:e0177275. [PMID: 28542273 PMCID: PMC5444648 DOI: 10.1371/journal.pone.0177275] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 04/25/2017] [Indexed: 12/24/2022] Open
Abstract
We have used high-throughput small RNA sequencing to characterize viral small RNA expression in purified tonsillar B and T lymphocytes isolated from patients tested positive for Epstein-Barr virus (EBV) or human adenovirus (HAdV) infections, respectively. In the small set of patients analyzed, the expression profile of EBV and HAdV miRNAs could not distinguish between patients diagnosed with tonsillar hypertrophy or chronic/recurrent tonsillitis. The EBV miR-BART expression profile among the patients diagnosed with tonsillar diseases resembles most closely the pattern seen in EBV+ tumors (Latency II/I). The miR-BARTs that appear to be absent in normal EBV infected cells are essentially all detectable in the diseased tonsillar B lymphocytes. In the EBV+ B cells we detected 44 EBV miR-BARTs derived from the proposed BART precursor hairpins whereof five are not annotated in miRBase v21. One previously undetected miRNA, BART16b-5p, originates from the miR-BART16 precursor hairpin as an alternative 5´ miR-BART16 located precisely upstream of the annotated miR-BART16-5p. Further, our analysis revealed an extensive sequence variation among the EBV miRNAs with isomiRs having a constant 5´ end but alternative 3´ ends. A range of small RNAs was also detected from the terminal stem of the EBER RNAs and the 3´ part of v-snoRNA1. During a lytic HAdV infection in established cell lines the terminal stem of the viral non-coding VA RNAs are processed to highly abundant viral miRNAs (mivaRNAs). In contrast, mivaRNA expression in HAdV positive tonsillar T lymphocytes was very low. The small RNA profile further showed that the 5´ mivaRNA from VA RNAI and the 3´ mivaRNA from VA RNAII were as predicted, whereas the 3´ mivaRNA from VA RNAI showed an aberrant processing upstream of the expected Dicer cleavage site.
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Affiliation(s)
- Farzaneh Assadian
- Department of Medical Biochemistry and Microbiology, Uppsala Biomedical Center, Uppsala University, Uppsala, Sweden
| | - Wael Kamel
- Department of Medical Biochemistry and Microbiology, Uppsala Biomedical Center, Uppsala University, Uppsala, Sweden
| | - Göran Laurell
- Department of Surgical Sciences, Otorhinolaryngology and Head and Neck Surgery, Uppsala University, Uppsala, Sweden
| | - Catharina Svensson
- Department of Medical Biochemistry and Microbiology, Uppsala Biomedical Center, Uppsala University, Uppsala, Sweden
| | - Tanel Punga
- Department of Medical Biochemistry and Microbiology, Uppsala Biomedical Center, Uppsala University, Uppsala, Sweden
| | - Göran Akusjärvi
- Department of Medical Biochemistry and Microbiology, Uppsala Biomedical Center, Uppsala University, Uppsala, Sweden
- * E-mail:
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31
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Human Cytomegalovirus MicroRNAs miR-US5-1 and miR-UL112-3p Block Proinflammatory Cytokine Production in Response to NF-κB-Activating Factors through Direct Downregulation of IKKα and IKKβ. mBio 2017; 8:mBio.00109-17. [PMID: 28270578 PMCID: PMC5340867 DOI: 10.1128/mbio.00109-17] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Emerging evidence indicates that human cytomegalovirus (HCMV) manipulates host cell signaling pathways using both proteins and noncoding RNAs. Several studies have shown that HCMV induces NF-κB signaling early in infection, resulting in the induction of antiviral proinflammatory cytokines with a subsequent reduction of these cytokines late in infection. The mechanism for late cytokine reduction is unknown. In this study, we show that HCMV microRNAs (miRNAs) miR-US5-1 and miR-UL112-3p target the IκB kinase (IKK) complex components IKKα and IKKβ to limit production of proinflammatory cytokines in response to interleukin 1β (IL-1β) and tumor necrosis factor alpha (TNF-α). Transfection of miR-UL112-3p and miR-US5-1 mimics reduced endogenous IKKα and IKKβ protein levels, and site-directed mutagenesis of the 3' untranslated regions (UTRs) identified the binding sites for each miRNA. Infection with mutant viruses lacking these miRNAs resulted in increased levels of IKKα and IKKβ proteins, an impaired ability to control NF-κB signaling at late times of lytic infection, and increased production of proinflammatory cytokines compared to wild-type virus in cell types relevant to HCMV infection in vivo These phenotypes were rescued by preexpression of miR-US5-1 and miR-UL112-3p in infected cells or by a miR-US5-1/miR-UL112-3p double mutant virus that expresses short hairpin RNAs (shRNAs) targeting IKKα and IKKβ, demonstrating the gene specificity of the miRNAs. These observations describe a mechanism through which HCMV miRNAs expressed late in the infectious cycle downregulate proinflammatory cytokine production to create a cellular proviral environment.IMPORTANCE Human cytomegalovirus (HCMV) is a significant cause of morbidity and mortality in transplant recipients and causes hearing loss and mental retardation when acquired congenitally. Initial events during HCMV infection result in the activation of NF-κB signaling, which culminates in the production of IL-6, CCL5, and TNF-α. Several viruses have developed mechanisms to block the antiviral effects of these cytokines. We show here that two HCMV miRNAs, miR-US5-1 and miR-UL112-3p, specifically downregulate IKKα and IKKβ signaling factors necessary to propagate NF-κB signaling and subsequent IL-6, CCL5, and TNF-α production. Regulation of these proinflammatory cytokines during lytic infection and during latency is critical to viral survival in the host.
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32
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Abstract
MicroRNAs are small, noncoding RNAs that posttranscriptionally regulate gene expression. The discovery of this relatively new mode of gene regulation as well as studies showing the prognostic value of viral and cellular miRNAs as biomarkers, such as in cancer progression, has stimulated the development of many methods to characterize miRNAs. EBV encodes 25 viral precursor microRNAs within its genome that are expressed during lytic and latent infection. In addition to viral miRNAs, EBV infection induces the expression of specific cellular oncogenic miRNAs, such as miR-155, miR-146a, miR-21, and others, that can contribute to the persistence of latently infected cells. This chapter describes several current techniques used to identify and detect the expression of viral and cellular miRNAs in EBV-infected cells.
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Affiliation(s)
- Rebecca L Skalsky
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, 505 NW 185th Avenue, Beaverton, OR, USA.
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33
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Choi H, Lee SK. TAX1BP1 downregulation by EBV-miR-BART15-3p enhances chemosensitivity of gastric cancer cells to 5-FU. Arch Virol 2016; 162:369-377. [PMID: 27757686 DOI: 10.1007/s00705-016-3109-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 10/05/2016] [Indexed: 12/11/2022]
Abstract
MicroRNAs (miRNAs) are a class of noncoding RNA molecules approximately 19 to 25 nucleotides in length that downregulate the expression of target genes at the post-transcriptional level by binding to the 3'-untranslated region (3'-UTR). Epstein-Barr virus (EBV) generates at least 44 miRNAs, but the functions of most of these miRNAs have not yet been identified. Previously, we reported BRUCE as a target of miR-BART15-3p, a miRNA produced by EBV, but our data suggested that there might be other apoptosis-associated target genes of miR-BART15-3p. Thus, in this study, we searched for new target genes of miR-BART15-3p using in silico analyses. We found a possible seed match site in the 3'-UTR of Tax1-binding protein 1 (TAX1BP1). The luciferase activity of a reporter vector including the 3'-UTR of TAX1BP1 was decreased by miR-BART15-3p. MiR-BART15-3p downregulated the expression of TAX1BP1 mRNA and protein in AGS cells, while an inhibitor against miR-BART15-3p upregulated the expression of TAX1BP1 mRNA and protein in AGS-EBV cells. Mir-BART15-3p modulated NF-κB activity in gastric cancer cell lines. Moreover, miR-BART15-3p strongly promoted chemosensitivity to 5-fluorouracil (5-FU). Our results suggest that miR-BART15-3p targets the anti-apoptotic TAX1BP1 gene in cancer cells, causing increased apoptosis and chemosensitivity to 5-FU.
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Affiliation(s)
- Hoyun Choi
- Department of Medical Lifescience, College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul, 06591, Republic of Korea
| | - Suk Kyeong Lee
- Department of Medical Lifescience, College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul, 06591, Republic of Korea.
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34
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Japanese Macaque Rhadinovirus Encodes a Viral MicroRNA Mimic of the miR-17 Family. J Virol 2016; 90:9350-63. [PMID: 27512057 DOI: 10.1128/jvi.01123-16] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 08/01/2016] [Indexed: 12/14/2022] Open
Abstract
UNLABELLED Japanese macaque (JM) rhadinovirus (JMRV) is a novel, gamma-2 herpesvirus that was recently isolated from JM with inflammatory demyelinating encephalomyelitis (JME). JME is a spontaneous and chronic disease with clinical characteristics and immunohistopathology comparable to those of multiple sclerosis in humans. Little is known about the molecular biology of JMRV. Here, we sought to identify and characterize the small RNAs expressed during lytic JMRV infection using deep sequencing. Fifteen novel viral microRNAs (miRNAs) were identified in JMRV-infected fibroblasts, all of which were readily detectable by 24 h postinfection and accumulated to high levels by 72 h. Sequence comparisons to human Kaposi's sarcoma-associated herpesvirus (KSHV) miRNAs revealed several viral miRNA homologs. To functionally characterize JMRV miRNAs, we screened for their effects on nuclear factor kappa B (NF-κB) signaling in the presence of two proinflammatory cytokines, tumor necrosis factor alpha (TNF-α) and interleukin-1β (IL-1β). Multiple JMRV miRNAs suppressed cytokine-induced NF-κB activation. One of these miRNAs, miR-J8, has seed sequence homology to members of the cellular miR-17/20/106 and miR-373 families, which are key players in cell cycle regulation as well as inflammation. Using reporters, we show that miR-J8 can target 3' untranslated regions (UTRs) with miR-17-5p or miR-20a cognate sites. Our studies implicate JMRV miRNAs in the suppression of innate antiviral immune responses, which is an emerging feature of many viral miRNAs. IMPORTANCE Gammaherpesviruses are associated with multiple diseases linked to immunosuppression and inflammation, including AIDS-related cancers and autoimmune diseases. JMRV is a recently identified herpesvirus that has been linked to JME, an inflammatory demyelinating disease in Japanese macaques that mimics multiple sclerosis. There are few large-animal models for gammaherpesvirus-associated pathogenesis. Here, we provide the first experimental evidence of JMRV miRNAs in vitro and demonstrate that one of these viral miRNAs can mimic the activity of the cellular miR-17/20/106 family. Our work provides unique insight into the roles of viral miRNAs during rhadinovirus infection and provides an important step toward understanding viral miRNA function in a nonhuman primate model system.
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Hooykaas MJG, Kruse E, Wiertz EJHJ, Lebbink RJ. Comprehensive profiling of functional Epstein-Barr virus miRNA expression in human cell lines. BMC Genomics 2016; 17:644. [PMID: 27531524 PMCID: PMC4987988 DOI: 10.1186/s12864-016-2978-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 07/28/2016] [Indexed: 12/21/2022] Open
Abstract
Background Epstein-Barr virus (EBV) establishes lifelong infections in its human host. The virus is associated with a broad range of malignancies of lymphoid and epithelial origin, including Burkitt’s lymphoma, post-transplant lymphoproliferative disease, nasopharyngeal carcinoma and gastric carcinoma. During the latent phase of its life cycle, EBV expresses more than 40 mature miRNAs that are highly abundant in tumor cells and may contribute to oncogenesis. Although multiple studies have assessed the relative expression profiles of EBV miRNAs in tumor cells, data linking these expression levels to functional target knockdown are mostly lacking. Therefore we set out to systematically assess the EBV miRNA expression levels in EBV+ tumor cell lines, and correlate this to their functional silencing capacity in these cells. Results We provide comprehensive EBV miRNA expression profiles of the EBV+ cell lines C666-1 (nasopharyngeal carcinoma), SNU-719 (gastric carcinoma), Jijoye (Burkitt’s lymphoma), and AKBM (Burkitt’s lymphoma) and of EBV− cells ectopically expressing the BART miRNA cluster. By deep sequencing the small RNA population and conducting miRNA-reporter experiments to assay miRNA potency, we were able to compare the expression profiles of the EBV miRNAs with their functional silencing efficacy. We observe a strong correlation between miRNA expression levels and functional miRNA activity. There is large variation in expression levels between EBV miRNAs in a given cell line, whereas the relative expression profiles are well maintained between cell lines. Furthermore, we show that miRNA arm selection bias is less pronounced for gamma-herpesvirus miRNAs than for human miRNAs. Conclusion We provide an in depth assessment of the expression levels and silencing activity of all EBV miRNAs in B- and epithelial cell lines of different latency stages. Our data show a good correlation between relative EBV miRNA expression levels and silencing capacity, and suggest preferential processing of particular EBV miRNAs irrespective of cell-type. In addition to encoding the largest number of precursor miRNAs of all human herpesviruses, EBV expresses many miRNAs precursors that yield two functional miRNA strands, rather than one guide strand and a non-functional passenger strand. This reduced strand bias may increase the size of the EBV miRNA targetome. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-2978-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Marjolein J G Hooykaas
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Elisabeth Kruse
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Emmanuel J H J Wiertz
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands.
| | - Robert Jan Lebbink
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands.
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Dittmer DP, Damania B, Sin SH. Animal models of tumorigenic herpesviruses--an update. Curr Opin Virol 2016; 14:145-50. [PMID: 26476352 DOI: 10.1016/j.coviro.2015.09.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 09/11/2015] [Accepted: 09/16/2015] [Indexed: 01/24/2023]
Abstract
Any one model system, be it culture or animal, only recapitulates one aspect of the viral life cycle in the human host. By providing recent examples of animal models for Epstein-Barr virus and Kaposi sarcoma-associated herpesvirus, we would argue that multiple animal models are needed to gain a comprehensive understanding of the pathogenesis associated with human oncogenic herpesviruses. Transgenic mice, homologous animal herpesviruses, and tumorgraft and humanized mouse models all complement each other in the study of viral pathogenesis. The use of animal model systems facilitates the exploration of novel anti-viral and anti-cancer treatment modalities for diseases associated with oncogenic herpesviruses.
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Affiliation(s)
- Dirk P Dittmer
- Lineberger Comprehensive Cancer Center, Department of Microbiology and Immunology, Center for AIDS Research (CfAR), School of Medicine, University of North Carolina, Chapel Hill, USA.
| | - Blossom Damania
- Lineberger Comprehensive Cancer Center, Department of Microbiology and Immunology, Center for AIDS Research (CfAR), School of Medicine, University of North Carolina, Chapel Hill, USA
| | - Sang-Hoon Sin
- Lineberger Comprehensive Cancer Center, Department of Microbiology and Immunology, Center for AIDS Research (CfAR), School of Medicine, University of North Carolina, Chapel Hill, USA
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Bernhardt K, Haar J, Tsai MH, Poirey R, Feederle R, Delecluse HJ. A Viral microRNA Cluster Regulates the Expression of PTEN, p27 and of a bcl-2 Homolog. PLoS Pathog 2016; 12:e1005405. [PMID: 26800049 PMCID: PMC4723338 DOI: 10.1371/journal.ppat.1005405] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 12/28/2015] [Indexed: 11/19/2022] Open
Abstract
The Epstein-Barr virus (EBV) infects and transforms B-lymphocytes with high efficiency. This process requires expression of the viral latent proteins and of the 3 miR-BHRF1 microRNAs. Here we show that B-cells infected by a virus that lacks these non-coding RNAs (Δ123) grew more slowly between day 5 and day 20, relative to wild type controls. This effect could be ascribed to a reduced S phase entry combined with a moderately increased apoptosis rate. Whilst the first phenotypic trait was consistent with an enhanced PTEN expression in B-cells infected with Δ123, the second could be explained by very low BHRF1 protein and RNA levels in the same cells. Indeed, B-cells infected either by a recombinant virus that lacks the BHRF1 protein, a viral bcl-2 homolog, or by Δ123 underwent a similar degree of apoptosis, whereas knockouts of both BHRF1 microRNAs and protein proved transformation-incompetent. We find that that the miR-BHRF1-3 seed regions, and to a lesser extent those of miR-BHRF1-2 mediate these stimulatory effects. After this critical period, B-cells infected with the Δ123 mutant recovered a normal growth rate and became more resistant to provoked apoptosis. This resulted from an enhanced BHRF1 protein expression relative to cells infected with wild type viruses and correlated with decreased p27 expression, two pro-oncogenic events. The upregulation of BHRF1 can be explained by the observation that large BHRF1 mRNAs are the source of BHRF1 protein but are destroyed following BHRF1 microRNA processing, in particular of miR-BHRF1-2. The BHRF1 microRNAs are unlikely to directly target p27 but their absence may facilitate the selection of B-cells that express low levels of this protein. Thus, the BHRF1 microRNAs allowed a time-restricted expression of the BHRF1 protein to innocuously expand the virus B-cell reservoir during the first weeks post-infection without increasing long-term immune pressure. This paper explains some of the molecular mechanisms used by the Epstein-Barr virus (EBV) BHRF1 microRNA cluster to enhance transformation of B-cells after infection. We find that B-cells exposed to a virus that lacks the BHRF1 microRNAs (Δ123) undergo more apoptosis and grow more slowly between the second and the fourth weeks after infection than cells infected by an intact virus. These effects are partly mediated by the viral protein BHRF1, a homolog of the anti-apoptotic bcl-2 protein. The viral microRNAs allow abundant expression of BHRF1 early after infection and its down-regulation when transformation has been established. The first effect is mediated by the seed regions of miR-BHRF1-2 and -3, whereas the second is dependent on RNA cleavage mediated by processing of miR-BHRF1-2. Furthermore, we found that the ability of the BHRF1 microRNAs to increase cell cycle entry is related to their ability to downregulate PTEN, a crucial negative regulator of the cell cycle. We also study the consequences of the absence of the microRNAs for the infected cells. B-cells infected with Δ123 become more resistant to apoptosis and express lower levels of p27, two events that facilitate the development of genome instability. Thus, the viral microRNAs allow rapid and innocuous expansion of infected B-cells, their long-term reservoir, thereby facilitating the life-long coexistence between the virus and its host.
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Affiliation(s)
- Katharina Bernhardt
- Pathogenesis of Virus Associated Tumors, German Cancer Research Center, Heidelberg, Germany
- Inserm unit U1074, Heidelberg, Germany
| | - Janina Haar
- Pathogenesis of Virus Associated Tumors, German Cancer Research Center, Heidelberg, Germany
- Inserm unit U1074, Heidelberg, Germany
| | - Ming-Han Tsai
- Pathogenesis of Virus Associated Tumors, German Cancer Research Center, Heidelberg, Germany
- Inserm unit U1074, Heidelberg, Germany
| | - Remy Poirey
- Pathogenesis of Virus Associated Tumors, German Cancer Research Center, Heidelberg, Germany
- Inserm unit U1074, Heidelberg, Germany
| | - Regina Feederle
- Pathogenesis of Virus Associated Tumors, German Cancer Research Center, Heidelberg, Germany
- Inserm unit U1074, Heidelberg, Germany
| | - Henri-Jacques Delecluse
- Pathogenesis of Virus Associated Tumors, German Cancer Research Center, Heidelberg, Germany
- Inserm unit U1074, Heidelberg, Germany
- * E-mail:
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Abstract
EBV expresses a number of viral noncoding RNAs (ncRNAs) during latent infection, many of which have known regulatory functions and can post-transcriptionally regulate viral and/or cellular gene expression. With recent advances in RNA sequencing technologies, the list of identified EBV ncRNAs continues to grow. EBV-encoded RNAs (EBERs) , the BamHI-A rightward transcripts (BARTs) , a small nucleolar RNA (snoRNA) , and viral microRNAs (miRNAs) are all expressed during EBV infection in a variety of cell types and tumors. Recently, additional novel EBV ncRNAs have been identified. Viral miRNAs, in particular, have been under extensive investigation since their initial identification over ten years ago. High-throughput studies to capture miRNA targets have revealed a number of miRNA-regulated viral and cellular transcripts that tie into important biological networks. Functions for many EBV ncRNAs are still unknown; however, roles for many EBV miRNAs in latency and in tumorigenesis have begun to emerge. Ongoing mechanistic studies to elucidate the functions of EBV ncRNAs should unravel additional roles for ncRNAs in the viral life cycle. In this chapter, we will discuss our current knowledge of the types of ncRNAs expressed by EBV, their potential roles in viral latency, and their potential involvement in viral pathogenesis.
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Haar J, Contrant M, Bernhardt K, Feederle R, Diederichs S, Pfeffer S, Delecluse HJ. The expression of a viral microRNA is regulated by clustering to allow optimal B cell transformation. Nucleic Acids Res 2015; 44:1326-41. [PMID: 26635399 PMCID: PMC4756819 DOI: 10.1093/nar/gkv1330] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 11/13/2015] [Indexed: 02/02/2023] Open
Abstract
The Epstein-Barr virus (EBV) transforms B cells by expressing latent proteins and the BHRF1 microRNA cluster. MiR-BHRF1–3, its most transforming member, belongs to the recently identified group of weakly expressed microRNAs. We show here that miR-BHRF1–3 displays an unusually low propensity to form a stem–loop structure, an effect potentiated by miR-BHRF1–3's proximity to the BHRF1 polyA site. Cloning miR-BHRF1–2 or a cellular microRNA, but not a ribozyme, 5′ of miR-BHRF1–3 markedly enhanced its expression. However, a virus carrying mutated miR-BHRF1–2 seed regions expressed miR-BHRF1–3 at normal levels and was fully transforming. Therefore, miR-BHRF1–2's role during transformation is independent of its seed regions, revealing a new microRNA function. Increasing the distance between miR-BHRF1–2 and miR-BHRF1–3 in EBV enhanced miR-BHRF1–3's expression but decreased its transforming potential. Thus, the expression of some microRNAs must be restricted to a narrow range, as achieved by placing miR-BHRF1–3 under the control of miR-BHRF1–2.
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Affiliation(s)
- Janina Haar
- Pathogenesis of Virus Associated Tumors, German Cancer Research Center, Im Neuenheimer Feld 242, 69120 Heidelberg, Germany Inserm unit U1074, Im Neuenheimer Feld 242, 69120 Heidelberg, Germany
| | - Maud Contrant
- Architecture et Réactivité de l'ARN - UPR 9002, Institut de Biologie Moléculaire et Cellulaire du CNRS, Université de Strasbourg, 15 rue René Descartes, F-67084 Strasbourg Cedex, France
| | - Katharina Bernhardt
- Pathogenesis of Virus Associated Tumors, German Cancer Research Center, Im Neuenheimer Feld 242, 69120 Heidelberg, Germany Inserm unit U1074, Im Neuenheimer Feld 242, 69120 Heidelberg, Germany
| | - Regina Feederle
- Pathogenesis of Virus Associated Tumors, German Cancer Research Center, Im Neuenheimer Feld 242, 69120 Heidelberg, Germany Inserm unit U1074, Im Neuenheimer Feld 242, 69120 Heidelberg, Germany
| | - Sven Diederichs
- Division of Cancer Research, Clinic for Thoracic Surgery, University Hospital Freiburg, Breisacher Str. 86b, 79110 Freiburg, Germany Division of RNA Biology & Cancer, German Cancer Research Center, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany & Institute of Pathology, University Hospital Heidelberg, Im Neuenheimer Feld 224, 69120 Heidelberg, Germany
| | - Sébastien Pfeffer
- Architecture et Réactivité de l'ARN - UPR 9002, Institut de Biologie Moléculaire et Cellulaire du CNRS, Université de Strasbourg, 15 rue René Descartes, F-67084 Strasbourg Cedex, France
| | - Henri-Jacques Delecluse
- Pathogenesis of Virus Associated Tumors, German Cancer Research Center, Im Neuenheimer Feld 242, 69120 Heidelberg, Germany Inserm unit U1074, Im Neuenheimer Feld 242, 69120 Heidelberg, Germany
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40
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Oxidative stress enables Epstein-Barr virus-induced B-cell transformation by posttranscriptional regulation of viral and cellular growth-promoting factors. Oncogene 2015; 35:3807-16. [PMID: 26592445 DOI: 10.1038/onc.2015.450] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 10/14/2015] [Accepted: 10/22/2015] [Indexed: 12/13/2022]
Abstract
Infection of human B lymphocytes by Epstein-Barr virus (EBV) leads to the establishment of immortalized lymphoblastoid cell lines (LCLs) that are widely used as a model of viral oncogenesis. An early consequence of infection is the induction of DNA damage and activation of the DNA damage response, which limits the efficiency of growth transformation. The cause of the DNA damage remains poorly understood. We have addressed this question by comparing the response of B lymphocytes infected with EBV or stimulated with a potent B-cell mitogen. We found that although the two stimuli induce comparable proliferation during the first 10 days of culture, the EBV-infected blasts showed significantly higher levels of DNA damage, which correlated with stronger and sustained accumulation of reactive oxygen species (ROS). Treatment with ROS scavengers decreased DNA damage in both mitogen-stimulated and EBV-infected cells. However, while mitogen-induced proliferation was slightly improved, the proliferation of EBV-infected cells and the establishment of LCLs were severely impaired. Quenching of ROS did not affect the kinetics and magnitude of viral gene expression but was associated with selective downregulation of the viral LMP1 and phosphorylated cellular transcription factor STAT3 that have key roles in transformation. Analysis of the mechanism by which high levels of ROS support LMP1 expression revealed selective inhibition of viral microRNAs that target the LMP1 transcript. Our study provides novel insights into the role of EBV-induced oxidative stress in promoting B-cell immortalization and malignant transformation.
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41
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Kamperschroer C, Gosink MM, Kumpf SW, O'Donnell LM, Tartaro KR. The genomic sequence of lymphocryptovirus from cynomolgus macaque. Virology 2015; 488:28-36. [PMID: 26590795 DOI: 10.1016/j.virol.2015.10.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 11/27/2014] [Accepted: 10/27/2015] [Indexed: 12/12/2022]
Abstract
Lymphocryptoviruses such as Epstein-Barr virus (EBV) cause persistent infections in human and non-human primates, and suppression of the immune system can increase the risk of lymphocryptovirus (LCV)-associated tumor development in both human and non-human primates. To enable LCV infection as a non-clinical model to study effects of therapeutics on EBV immunity, we determined the genomic DNA sequence of the LCV from cynomolgus macaque, a species commonly used for non-clinical testing. Comparison to rhesus macaque LCV and human EBV sequences indicates that LCV from the cynomolgus macaque has the same genomic arrangement and a high degree of similarity in most genes, especially with rhesus macaque LCV. Genes showing lower similarity were those encoding proteins involved in latency and/or tumor promotion or immune evasion. The genomic sequence of LCV from cynomolgus macaque should aid the development of non-clinical tools for identifying therapeutics that impact LCV immunity and carry potential lymphoma risk.
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Affiliation(s)
- Cris Kamperschroer
- Drug Safety Research and Development, Pfizer Global Research and Development, Pfizer, Inc., Groton, CT, USA.
| | - Mark M Gosink
- Drug Safety Research and Development, Pfizer Global Research and Development, Pfizer, Inc., Groton, CT, USA
| | - Steven W Kumpf
- Drug Safety Research and Development, Pfizer Global Research and Development, Pfizer, Inc., Groton, CT, USA
| | - Lynn M O'Donnell
- Drug Safety Research and Development, Pfizer Global Research and Development, Pfizer, Inc., Groton, CT, USA
| | - Karrie R Tartaro
- Drug Safety Research and Development, Pfizer Global Research and Development, Pfizer, Inc., Groton, CT, USA
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42
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Epstein-Barr Viruses (EBVs) Deficient in EBV-Encoded RNAs Have Higher Levels of Latent Membrane Protein 2 RNA Expression in Lymphoblastoid Cell Lines and Efficiently Establish Persistent Infections in Humanized Mice. J Virol 2015; 89:11711-4. [PMID: 26339045 PMCID: PMC4645642 DOI: 10.1128/jvi.01873-15] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 08/25/2015] [Indexed: 01/26/2023] Open
Abstract
Functions of Epstein-Barr virus (EBV)-encoded RNAs (EBERs) were tested in lymphoblastoid cell lines containing EBER mutants of EBV. Binding of EBER1 to ribosomal protein L22 (RPL22) was confirmed. Deletion of EBER1 or EBER2 correlated with increased levels of cytoplasmic EBV LMP2 RNA and with small effects on specific cellular microRNA (miRNA) levels, but protein levels of LMP1 and LMP2A were not affected. Wild-type EBV and EBER deletion EBV had approximately equal abilities to infect immunodeficient mice reconstituted with a human hematopoietic system.
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43
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Wang L, Li G, Yao ZQ, Moorman JP, Ning S. MicroRNA regulation of viral immunity, latency, and carcinogenesis of selected tumor viruses and HIV. Rev Med Virol 2015; 25:320-41. [PMID: 26258805 DOI: 10.1002/rmv.1850] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Revised: 06/09/2015] [Accepted: 06/28/2015] [Indexed: 12/11/2022]
Abstract
MicroRNAs (miRNAs) function as key regulators in immune responses and cancer development. In the contexts of infection with oncogenic viruses, miRNAs are engaged in viral persistence, latency establishment and maintenance, and oncogenesis. In this review, we summarize the potential roles and mechanisms of viral and cellular miRNAs in the host-pathogen interactions during infection with selected tumor viruses and HIV, which include (i) repressing viral replication and facilitating latency establishment by targeting viral transcripts, (ii) evading innate and adaptive immune responses via toll-like receptors, RIG-I-like receptors, T-cell receptor, and B-cell receptor pathways by targeting signaling molecules such as TRAF6, IRAK1, IKKε, and MyD88, as well as downstream targets including regulatory cytokines such as tumor necrosis factor α, interferon γ, interleukin 10, and transforming growth factor β, (iii) antagonizing intrinsic and extrinsic apoptosis pathways by targeting pro-apoptotic or anti-apoptotic gene transcripts such as the Bcl-2 family and caspase-3, (iv) modulating cell proliferation and survival through regulation of the Wnt, PI3K/Akt, Erk/MAPK, and Jak/STAT signaling pathways, as well as the signaling pathways triggered by viral oncoproteins such as Epstein-Barr Virus LMP1, by targeting Wnt-inhibiting factor 1, SHIP, pTEN, and SOCSs, and (v) regulating cell cycle progression by targeting cell cycle inhibitors such as p21/WAF1 and p27/KIP1. Further elucidation of the interaction between miRNAs and these key biological events will facilitate our understanding of the pathogenesis of viral latency and oncogenesis and may lead to the identification of miRNAs as novel targets for developing new therapeutic or preventive interventions.
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Affiliation(s)
- Ling Wang
- Center of Excellence for Inflammation, Infectious Diseases and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA.,Division of Infectious Diseases, Department of Internal Medicine, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | - Guangyu Li
- Center of Excellence for Inflammation, Infectious Diseases and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA.,Division of Infectious Diseases, Department of Internal Medicine, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | - Zhi Q Yao
- Center of Excellence for Inflammation, Infectious Diseases and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA.,Division of Infectious Diseases, Department of Internal Medicine, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA.,Hepatitis (HCV/HIV) Program, James H Quillen VA Medical Center, Johnson City, TN, USA
| | - Jonathan P Moorman
- Center of Excellence for Inflammation, Infectious Diseases and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA.,Division of Infectious Diseases, Department of Internal Medicine, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA.,Hepatitis (HCV/HIV) Program, James H Quillen VA Medical Center, Johnson City, TN, USA
| | - Shunbin Ning
- Center of Excellence for Inflammation, Infectious Diseases and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA.,Division of Infectious Diseases, Department of Internal Medicine, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
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Kang D, Skalsky RL, Cullen BR. EBV BART MicroRNAs Target Multiple Pro-apoptotic Cellular Genes to Promote Epithelial Cell Survival. PLoS Pathog 2015; 11:e1004979. [PMID: 26070070 PMCID: PMC4466530 DOI: 10.1371/journal.ppat.1004979] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 05/26/2015] [Indexed: 01/07/2023] Open
Abstract
Epstein-Barr virus (EBV) is a ubiquitous human γ-herpesvirus that can give rise to cancers of both B-cell and epithelial cell origin. In EBV-induced cancers of epithelial origin, including nasopharyngeal carcinomas (NPCs) and gastric carcinomas, the latent EBV genome expresses very high levels of a cluster of 22 viral pre-miRNAs, called the miR-BARTs, and these have previously been shown to confer a degree of resistance to pro-apoptotic drugs. Here, we present an analysis of the ability of individual miR-BART pre-miRNAs to confer an anti-apoptotic phenotype and report that five of the 22 miR-BARTs demonstrate this ability. We next used photoactivatable ribonucleoside-enhanced crosslinking and immunoprecipitation (PAR-CLIP) to globally identify the mRNA targets bound by these miR-BARTs in latently infected epithelial cells. This led to the identification of ten mRNAs encoding pro-apoptotic mRNA targets, all of which could be confirmed as valid targets for the five anti-apoptotic miR-BARTs by indicator assays and by demonstrating that ectopic expression of physiological levels of the relevant miR-BART in the epithelial cell line AGS resulted in a significant repression of the target mRNA as well as the encoded protein product. Using RNA interference, we further demonstrated that knockdown of at least seven of these cellular miR-BART target transcripts phenocopies the anti-apoptotic activity seen upon expression of the relevant EBV miR-BART miRNA. Together, these observations validate previously published reports arguing that the miR-BARTs can exert an anti-apoptotic effect in EBV-infected epithelial cells and provide a mechanistic explanation for this activity. Moreover, these results identify and validate a substantial number of novel mRNA targets for the anti-apoptotic miR-BARTs.
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Affiliation(s)
- Dong Kang
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
- Center for Virology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Rebecca L. Skalsky
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
- Center for Virology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Bryan R. Cullen
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
- Center for Virology, Duke University Medical Center, Durham, North Carolina, United States of America
- * E-mail:
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45
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Pan-viral-microRNA screening identifies interferon inhibition as a common function of diverse viruses. Proc Natl Acad Sci U S A 2015; 112:1856-61. [PMID: 25624489 DOI: 10.1073/pnas.1417891112] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Diverse viruses encode regulatory RNAs called microRNAs (miRNAs). Despite much progress, the functions of the majority of viral miRNAs remain unknown. Most previous studies have used biochemical methods to uncover targets of viral miRNAs, but it is unclear what fraction of these targets is functionally important. Here, we apply an alternative strategy based on the premise that assorted viral miRNAs will share functionality. Screening a library of >70 human viral miRNAs showed that three unrelated miRNAs from distantly related herpesviruses significantly inhibited IFN signaling. Strikingly, each of these miRNAs directly reduced expression of the cyclic AMP-responsive element-binding protein (CBP), which as part of the p300-CBP complex, mediates IFN signaling. We show that both 5' and 3' derivatives from Epstein-Barr virus (EBV) encoded miR-BART-18 precursor miRNA (pre-miRNA) and the orthologous pre-miRNA from Rhesus lymphocryptovirus contribute to reducing IFN signaling. Thus, through both convergent and divergent evolutionary mechanisms, varied herpesviral miRNAs share the ability to decrease IFN signaling. Restoring miR-BART-18 to cells infected with an EBV miRNA mutant conveyed a cellular growth advantage upon IFN treatment, and relevant miRNAs from other herpesviruses were able to complement this activity. Blocking miR-BART-18 function in an EBV(+) tumor cell line renders cells more susceptible to IFN-mediated effects. These findings provide a mechanism that can at least partially explain the resistance of some EBV-associated tumors to IFN therapy. Our work suggests that similar pan-viral-miRNA functional-based screening strategies are warranted for determining relevant activities of other viral miRNAs.
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Cox JE, Sullivan CS. Balance and Stealth: The Role of Noncoding RNAs in the Regulation of Virus Gene Expression. Annu Rev Virol 2014; 1:89-109. [PMID: 26958716 DOI: 10.1146/annurev-virology-031413-085439] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In the past two decades, our knowledge of gene regulation has been greatly expanded by the discovery of microRNAs (miRNAs). miRNAs are small (19-24 nt) noncoding RNAs (ncRNAs) found in metazoans, plants, and some viruses. They have been shown to regulate many cellular processes, including differentiation, maintenance of homeostasis, apoptosis, and the immune response. At present, there are over 300 known viral miRNAs encoded by diverse virus families. One well-characterized function of some viral miRNAs is the regulation of viral transcripts. Host miRNAs can also regulate viral gene expression. We propose that viruses take advantage of both host and viral ncRNA regulation to balance replication and infectious state (for example, latent versus lytic infection). As miRNA regulation can be reversed upon certain cellular stresses, we hypothesize that ncRNAs can serve viruses as barometers for cellular stress.
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Affiliation(s)
- Jennifer E Cox
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712;
| | - Christopher S Sullivan
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712;
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Cullen BR. Interview with Bryan R Cullen. Future Virol 2014. [DOI: 10.2217/fvl.14.17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Identification of novel, highly expressed retroviral microRNAs in cells infected by bovine foamy virus. J Virol 2014; 88:4679-86. [PMID: 24522910 DOI: 10.1128/jvi.03587-13] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED While numerous viral microRNAs (miRNAs) expressed by DNA viruses, especially herpesvirus family members, have been reported, there have been very few reports of miRNAs derived from RNA viruses. Here we describe three miRNAs expressed by bovine foamy virus (BFV), a member of the spumavirus subfamily of retroviruses, in both BFV-infected cultured cells and BFV-infected cattle. All three viral miRNAs are initially expressed in the form of an ∼ 122-nucleotide (nt) pri-miRNA, encoded within the BFV long terminal repeat U3 region, that is subsequently cleaved to generate two pre-miRNAs that are then processed to yield three distinct, biologically active miRNAs. The BFV pri-miRNA is transcribed by RNA polymerase III, and the three resultant mature miRNAs were found to contribute a remarkable ∼ 70% of all miRNAs expressed in BFV-infected cells. These data document the second example of a retrovirus that is able to express viral miRNAs by using embedded proviral RNA polymerase III promoters. IMPORTANCE Foamy viruses are a ubiquitous family of nonpathogenic retroviruses that have potential as gene therapy vectors in humans. Here we demonstrate that bovine foamy virus (BFV) expresses high levels of three viral microRNAs (miRNAs) in BFV-infected cells in culture and also in infected cattle. The BFV miRNAs are unusual in that they are initially transcribed by RNA polymerase III as a single, ∼ 122-nt pri-miRNA that is subsequently processed to release three fully functional miRNAs. The observation that BFV, a foamy virus, is able to express viral miRNAs in infected cells adds to emerging evidence that miRNA expression is a common, albeit clearly not universal, property of retroviruses and suggests that these miRNAs may exert a significant effect on viral replication in vivo.
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