1
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Mudedla S, Lee H, Kim JJ, Jang SH, Doddareddy MR, Sanam SY, Gundabathula R, Park JJ, Wu S. Molecular Dynamics Simulation on the Suppression Mechanism of Phosphorylation to Ser222 by Allosteric Inhibitors Targeting MEK1/2 Kinase. ACS OMEGA 2024; 9:31946-31956. [PMID: 39072081 PMCID: PMC11270731 DOI: 10.1021/acsomega.4c03615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 06/18/2024] [Accepted: 06/20/2024] [Indexed: 07/30/2024]
Abstract
Allosteric inhibitors of mitogen-activated protein kinase 1 (MEK1) reveal distinct interactions with MEK1 activation loop residues. The structural analyses will determine whether, and how, distinct inhibitors suppress the phosphorylation of MEK1 and may guide future therapeutic development. In this study, we explored the suppression mechanism of the phosphorylation process in the presence of MEK allosteric inhibitors, such as selumetinib, trametinib, cobimetinib, and CH5126766, by employing molecular dynamics simulations accompanied by principal component analysis. The simulations of wildtype MEK1 show that Ser222 can come close to γ-phosphate but not Ser218. We have found the conformation where Ser222 is within 5 Å of distance, which makes Ser222 accessible for γ-phosphate. The conformation analysis from the simulations of MEK1 in the presence of allosteric inhibitors reveals that the inhibitor restricts the flexibility of Ser222 through strong interactions with the activation loop, Lys97, and water mediates interactions with amino acids in the vicinity. The results reveal that all the inhibitors act as screeners between the activation loop and Mg-ATP and restricting the flexibility of the activation loop through strong interaction causes the suppression of the phosphorylation process of MEK1. The results conclude that a strong interaction of allosteric inhibitors with the activation loop restricts the movement of Ser222 toward Mg-ATP, which could be the dominant factor for the suppression of phosphorylation in MEK1. This research will provide novel insights to design effective anticancer therapeutics for targeting MEK1 in the future.
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Affiliation(s)
- Sathish
K. Mudedla
- PharmCADD,
224, Engineering Building 7, Sinseon-Ro 365, Namgu, Busan 48548, Korea
| | - Hayoung Lee
- Drug
Discovery Division, ISU Abxis, Bundang-gu, Seongnam-si, Gyeonggi-do 13488, Korea
| | - Jeom Ji Kim
- Drug
Discovery Division, ISU Abxis, Bundang-gu, Seongnam-si, Gyeonggi-do 13488, Korea
| | - Seong Hun Jang
- PharmCADD,
224, Engineering Building 7, Sinseon-Ro 365, Namgu, Busan 48548, Korea
| | | | - Swetha Y. Sanam
- PharmCADD,
224, Engineering Building 7, Sinseon-Ro 365, Namgu, Busan 48548, Korea
| | - Rochish Gundabathula
- PharmCADD,
224, Engineering Building 7, Sinseon-Ro 365, Namgu, Busan 48548, Korea
| | - Jang-June Park
- Drug
Discovery Division, ISU Abxis, Bundang-gu, Seongnam-si, Gyeonggi-do 13488, Korea
| | - Sangwook Wu
- PharmCADD,
224, Engineering Building 7, Sinseon-Ro 365, Namgu, Busan 48548, Korea
- Department
of Physics, Pukyong National University, Busan 48513, Korea
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2
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Lee SC, Naik NG, Tombácz D, Gulyás G, Kakuk B, Boldogkői Z, Hall K, Papp B, Boulant S, Toth Z. Hypoxia and HIF-1α promote lytic de novo KSHV infection. J Virol 2023; 97:e0097223. [PMID: 37909728 PMCID: PMC10688315 DOI: 10.1128/jvi.00972-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Accepted: 10/12/2023] [Indexed: 11/03/2023] Open
Abstract
IMPORTANCE The current view is that the default pathway of Kaposi's sarcoma-associated herpesvirus (KSHV) infection is the establishment of latency, which is a prerequisite for lifelong infection and viral oncogenesis. This view about KSHV infection is supported by the observations that KSHV latently infects most of the cell lines cultured in vitro in the absence of any environmental stresses that may occur in vivo. The goal of this study was to determine the effect of hypoxia, a natural stress stimulus, on primary KSHV infection. Our data indicate that hypoxia promotes euchromatin formation on the KSHV genome following infection and supports lytic de novo KSHV infection. We also discovered that hypoxia-inducible factor-1α is required and sufficient for allowing lytic KSHV infection. Based on our results, we propose that hypoxia promotes lytic de novo infection in cells that otherwise support latent infection under normoxia; that is, the environmental conditions can determine the outcome of KSHV primary infection.
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Affiliation(s)
- See-Chi Lee
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, Florida, USA
| | - Nenavath Gopal Naik
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, Florida, USA
| | - Dóra Tombácz
- Department of Medical Biology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Gábor Gulyás
- Department of Medical Biology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Balázs Kakuk
- Department of Medical Biology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Zsolt Boldogkői
- Department of Medical Biology, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Kevin Hall
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, Florida, USA
| | - Bernadett Papp
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, Florida, USA
- UF Genetics Institute, Gainesville, Florida, USA
- UF Health Cancer Center, Gainesville, Florida, USA
- UF Center for Orphaned Autoimmune Disorders, Gainesville, Florida, USA
- UF Informatics Institute, Gainesville, Florida, USA
| | - Steeve Boulant
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Zsolt Toth
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, Florida, USA
- UF Genetics Institute, Gainesville, Florida, USA
- UF Health Cancer Center, Gainesville, Florida, USA
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3
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Han L, Haefner V, Yu Y, Han B, Ren H, Irmler M, Beckers J, Liu Q, Feuchtinger A, Yildirim AO, Adler H, Stoeger T. Nanoparticle-Exposure-Triggered Virus Reactivation Induces Lung Emphysema in Mice. ACS NANO 2023; 17:21056-21072. [PMID: 37856828 PMCID: PMC10655245 DOI: 10.1021/acsnano.3c04111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 10/04/2023] [Accepted: 10/05/2023] [Indexed: 10/21/2023]
Abstract
Nanoparticles (NPs) released from engineered materials or combustion processes as well as persistent herpesvirus infection are omnipresent and are associated with chronic lung diseases. Previously, we showed that pulmonary exposure of a single dose of soot-like carbonaceous NPs (CNPs) or fiber-shaped double-walled carbon nanotubes (DWCNTs) induced an increase of lytic virus protein expression in mouse lungs latently infected with murine γ-herpesvirus 68 (MHV-68), with a similar pattern to acute infection suggesting virus reactivation. Here we investigate the effects of a more relevant repeated NP exposure on lung disease development as well as herpesvirus reactivation mechanistically and suggest an avenue for therapeutic prevention. In the MHV-68 mouse model, progressive lung inflammation and emphysema-like injury were detected 1 week after repetitive CNP and DWCNT exposure. NPs reactivated the latent herpesvirus mainly in CD11b+ macrophages in the lungs. In vitro, in persistently MHV-68 infected bone marrow-derived macrophages, ERK1/2, JNK, and p38 MAPK were rapidly activated after CNP and DWCNT exposure, followed by viral gene expression and increased viral titer but without generating a pro-inflammatory signature. Pharmacological inhibition of p38 activation abrogated CNP- but not DWCNT-triggered virus reactivation in vitro, and inhibitor pretreatment of latently infected mice attenuated CNP-exposure-induced pulmonary MHV-68 reactivation. Our findings suggest a crucial contribution of particle-exposure-triggered herpesvirus reactivation for nanomaterial exposure or air pollution related lung emphysema development, and pharmacological p38 inhibition might serve as a protective target to alleviate air pollution related chronic lung disease exacerbations. Because of the required precondition of latent infection described here, the use of single hit models might have severe limitations when assessing the respiratory toxicity of nanoparticle exposure.
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Affiliation(s)
- Lianyong Han
- Institute
of Lung Health and Immunity (LHI), Comprehensive Pneumology Center, Helmholtz Zentrum München, German Research
Center for Environmental Health, 85764 Neuherberg, Germany
- Member
of the German Center of Lung Research (DZL), 81377 Munich, Germany
| | - Verena Haefner
- Institute
of Lung Health and Immunity (LHI), Comprehensive Pneumology Center, Helmholtz Zentrum München, German Research
Center for Environmental Health, 85764 Neuherberg, Germany
- Member
of the German Center of Lung Research (DZL), 81377 Munich, Germany
| | - Youjia Yu
- Department
of Forensic Medicine, Nanjing Medical University, 211166 Nanjing, Jiangsu, China
| | - Bing Han
- Laboratory
of Translational Research “Stress and Immunity”, Department
of Anesthesiology, LMU Hospital, Ludwig-Maximilians-University
Munich, 81377 Munich, Germany
| | - Hongyu Ren
- Institute
of Lung Health and Immunity (LHI), Comprehensive Pneumology Center, Helmholtz Zentrum München, German Research
Center for Environmental Health, 85764 Neuherberg, Germany
- Member
of the German Center of Lung Research (DZL), 81377 Munich, Germany
| | - Martin Irmler
- Institute
of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764 Neuherberg, Germany
| | - Johannes Beckers
- Institute
of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764 Neuherberg, Germany
- German Center
for Diabetes Research (DZD), 85764 Neuherberg, Germany
- Technische
Universität München, Chair
of Experimental Genetics, 80539 Munich, Germany
| | - Qiongliang Liu
- Institute
of Lung Health and Immunity (LHI), Comprehensive Pneumology Center, Helmholtz Zentrum München, German Research
Center for Environmental Health, 85764 Neuherberg, Germany
- Member
of the German Center of Lung Research (DZL), 81377 Munich, Germany
| | - Annette Feuchtinger
- Research
Unit Analytical Pathology, Helmholtz Zentrum
München, German Research Center for Environmental Health, 85764 Neuherberg, Germany
| | - Ali Oender Yildirim
- Institute
of Lung Health and Immunity (LHI), Comprehensive Pneumology Center, Helmholtz Zentrum München, German Research
Center for Environmental Health, 85764 Neuherberg, Germany
- Institute
of Experimental Pneumology, University Hospital, Ludwig-Maximilians University, 81377 Munich, Germany
- Member
of the German Center of Lung Research (DZL), 81377 Munich, Germany
| | - Heiko Adler
- Institute
of Asthma and Allergy Prevention, Helmholtz
Zentrum München, German Research Center for Environmental Health, 85764 Neuherberg, Germany
- Walther Straub
Institute of Pharmacology and Toxicology, Ludwig-Maximilians-University Munich, 80336 Munich, Germany
- Member
of the German Center of Lung Research (DZL), 81377 Munich, Germany
| | - Tobias Stoeger
- Institute
of Lung Health and Immunity (LHI), Comprehensive Pneumology Center, Helmholtz Zentrum München, German Research
Center for Environmental Health, 85764 Neuherberg, Germany
- Member
of the German Center of Lung Research (DZL), 81377 Munich, Germany
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4
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Olson AT, Kang Y, Ladha AM, Zhu S, Lim CB, Nabet B, Lagunoff M, Gujral TS, Geballe AP. Polypharmacology-based kinome screen identifies new regulators of KSHV reactivation. PLoS Pathog 2023; 19:e1011169. [PMID: 37669313 PMCID: PMC10503724 DOI: 10.1371/journal.ppat.1011169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 09/15/2023] [Accepted: 08/16/2023] [Indexed: 09/07/2023] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) causes several human diseases including Kaposi's sarcoma (KS), a leading cause of cancer in Africa and in patients with AIDS. KS tumor cells harbor KSHV predominantly in a latent form, while typically <5% contain lytic replicating virus. Because both latent and lytic stages likely contribute to cancer initiation and progression, continued dissection of host regulators of this biological switch will provide insights into fundamental pathways controlling the KSHV life cycle and related disease pathogenesis. Several cellular protein kinases have been reported to promote or restrict KSHV reactivation, but our knowledge of these signaling mediators and pathways is incomplete. We employed a polypharmacology-based kinome screen to identify specific kinases that regulate KSHV reactivation. Those identified by the screen and validated by knockdown experiments included several kinases that enhance lytic reactivation: ERBB2 (HER2 or neu), ERBB3 (HER3), ERBB4 (HER4), MKNK2 (MNK2), ITK, TEC, and DSTYK (RIPK5). Conversely, ERBB1 (EGFR1 or HER1), MKNK1 (MNK1) and FRK (PTK5) were found to promote the maintenance of latency. Mechanistic characterization of ERBB2 pro-lytic functions revealed a signaling connection between ERBB2 and the activation of CREB1, a transcription factor that drives KSHV lytic gene expression. These studies provided a proof-of-principle application of a polypharmacology-based kinome screen for the study of KSHV reactivation and enabled the discovery of both kinase inhibitors and specific kinases that regulate the KSHV latent-to-lytic replication switch.
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Affiliation(s)
- Annabel T. Olson
- Division of Human Biology, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Yuqi Kang
- Division of Human Biology, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Anushka M. Ladha
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Songli Zhu
- Division of Human Biology, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Chuan Bian Lim
- Division of Human Biology, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Behnam Nabet
- Division of Human Biology, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
| | - Michael Lagunoff
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Taranjit S. Gujral
- Division of Human Biology, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
- Department of Pharmacology, University of Washington, Seattle, Washington, United States of America
| | - Adam P. Geballe
- Division of Human Biology, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
- Division of Clinical Research, Fred Hutchinson Cancer Center, Seattle, Washington, United States of America
- Department of Medicine, University of Washington, Seattle, Washington, United States of America
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5
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Atyeo N, Chae MY, Toth Z, Sharma A, Papp B. Kaposi's Sarcoma-Associated Herpesvirus Immediate Early Proteins Trigger FOXQ1 Expression in Oral Epithelial Cells, Engaging in a Novel Lytic Cycle-Sustaining Positive Feedback Loop. J Virol 2023; 97:e0169622. [PMID: 36815831 PMCID: PMC10062149 DOI: 10.1128/jvi.01696-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 02/02/2023] [Indexed: 02/24/2023] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) is an oncogenic gammaherpesvirus that can replicate in oral epithelial cells to promote viral transmission via saliva. To identify novel regulators of KSHV oral infection, we performed a transcriptome analysis of KSHV-infected primary human gingival epithelial (HGEP) cells, which identified the gene coding for the host transcription factor FOXQ1 as the top induced host gene. FOXQ1 is nearly undetectable in uninfected HGEP and telomerase-immortalized gingival keratinocytes (TIGK) cells but is highly expressed within hours of KSHV infection. We found that while the FOXQ1 promoter lacks activating histone acetylation marks in uninfected oral epithelial cells, these marks accumulate in the FOXQ1 promoter in infected cells, revealing a rapid epigenetic reprogramming event. To evaluate FOXQ1 function, we depleted FOXQ1 in KSHV-infected TIGK cells, which resulted in reduced accumulation of KSHV lytic proteins and viral DNA over the course of 4 days of infection, uncovering a novel lytic cycle-sustaining role of FOXQ1. A screen of KSHV lytic proteins demonstrated that the immediate early proteins ORF45 and replication and transcription activator (RTA) were both sufficient for FOXQ1 induction in oral epithelial cells, indicating active involvement of incoming and rapidly expressed factors in altering host gene expression. ORF45 is known to sustain extracellular signal-regulated kinase (ERK) p90 ribosomal s6 kinase (RSK) pathway activity to promote lytic infection. We found that an ORF45 mutant lacking RSK activation function failed to induce FOXQ1 in TIGK cells, revealing that ORF45 uses a shared mechanism to rapidly induce both host and viral genes to sustain lytic infection in oral epithelial cells. IMPORTANCE The oral cavity is a primary site of initial contact and entry for many viruses. Viral replication in the oral epithelium promotes viral shedding in saliva, allowing interpersonal transmission, as well as spread to other cell types, where chronic infection can be established. Understanding the regulation of KSHV infection in the oral epithelium would allow for the design of universal strategies to target the first stage of viral infection, thereby halting systemic viral pathogenesis. Overall, we uncover a novel positive feedback loop in which immediate early KSHV factors drive rapid host reprogramming of oral epithelial cells to sustain the lytic cycle in the oral cavity.
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Affiliation(s)
- Natalie Atyeo
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - Min Young Chae
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - Zsolt Toth
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
- Genetics Institute, University of Florida, Gainesville, Florida, USA
- Health Cancer Center, University of Florida, Gainesville, Florida, USA
| | - Aria Sharma
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - Bernadett Papp
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, Florida, USA
- Genetics Institute, University of Florida, Gainesville, Florida, USA
- Health Cancer Center, University of Florida, Gainesville, Florida, USA
- Informatics Institute, University of Florida, Gainesville, Florida, USA
- Center for Orphaned Autoimmune Disorders, University of Florida, Gainesville, Florida, USA
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6
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Lari A, Glaunsinger BA. Murine Gammaherpesvirus 68 ORF45 Stimulates B2 Retrotransposon and Pre-tRNA Activation in a Manner Dependent on Mitogen-Activated Protein Kinase (MAPK) Signaling. Microbiol Spectr 2023; 11:e0017223. [PMID: 36752632 PMCID: PMC10100704 DOI: 10.1128/spectrum.00172-23] [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: 01/13/2023] [Accepted: 01/21/2023] [Indexed: 02/09/2023] Open
Abstract
RNA polymerase III (RNAPIII) transcribes a variety of noncoding RNAs, including tRNA (tRNA) and the B2 family of short interspersed nuclear elements (SINEs). B2 SINEs are noncoding retrotransposons that possess tRNA-like promoters and are normally silenced in healthy somatic tissue. Infection with the murine gammaherpesvirus MHV68 induces transcription of both SINEs and tRNAs, in part through the activity of the viral protein kinase ORF36. Here, we identify the conserved MHV68 tegument protein ORF45 as an additional activator of these RNAPIII loci. MHV68 ORF45 and ORF36 form a complex, resulting in an additive induction RNAPIII and increased ORF45 expression. ORF45-induced RNAPIII transcription is dependent on its activation of the extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase (MAPK) signaling pathway, which in turn increases the abundance of the RNAPIII transcription factor Brf1. Other viral and nonviral activators of MAPK/ERK signaling also increase the levels of Brf1 protein, B2 SINE RNA, and tRNA, suggesting that this is a common strategy to increase RNAPIII activity. IMPORTANCE Gammaherpesviral infection alters the gene expression landscape of a host cell, including through the induction of noncoding RNAs transcribed by RNA polymerase III (RNAPIII). Among these are a class of repetitive genes known as retrotransposons, which are normally silenced elements and can copy and spread throughout the genome, and transfer RNAs (tRNAs), which are fundamental components of protein translation machinery. How these loci are activated during infection is not well understood. Here, we identify ORF45 from the model murine gammaherpesvirus MHV68 as a novel activator of RNAPIII transcription. To do so, it engages the MAPK/ERK signaling pathway, which is a central regulator of cellular response to environmental stimuli. Activation of this pathway leads to the upregulation of a key factor required for RNAPIII activity, Brf1. These findings expand our understanding of the regulation and dysregulation of RNAPIII transcription and highlight how viral cooption of key signaling pathways can impact host gene expression.
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Affiliation(s)
- Azra Lari
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, USA
| | - Britt A. Glaunsinger
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, USA
- Howard Hughes Medical Institute, Berkeley, California, USA
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7
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Olson AT, Kang Y, Ladha AM, Lim CB, Lagunoff M, Gujral TS, Geballe AP. Polypharmacology-based kinome screen identifies new regulators of KSHV reactivation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.01.526589. [PMID: 36778430 PMCID: PMC9915688 DOI: 10.1101/2023.02.01.526589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) causes several human diseases including Kaposi's sarcoma (KS), a leading cause of cancer in Africa and in patients with AIDS. KS tumor cells harbor KSHV predominantly in a latent form, while typically <5% contain lytic replicating virus. Because both latent and lytic stages likely contribute to cancer initiation and progression, continued dissection of host regulators of this biological switch will provide insights into fundamental pathways controlling the KSHV life cycle and related disease pathogenesis. Several cellular protein kinases have been reported to promote or restrict KSHV reactivation, but our knowledge of these signaling mediators and pathways is incomplete. We employed a polypharmacology-based kinome screen to identifiy specific kinases that regulate KSHV reactivation. Those identified by the screen and validated by knockdown experiments included several kinases that enhance lytic reactivation: ERBB2 (HER2 or neu ), ERBB3 (HER3), ERBB4 (HER4), MKNK2 (MNK2), ITK, TEC, and DSTYK (RIPK5). Conversely, ERBB1 (EGFR1 or HER1), MKNK1 (MNK1) and FRK (PTK5) were found to promote the maintenance of latency. Mechanistic characterization of ERBB2 pro-lytic functions revealed a signaling connection between ERBB2 and the activation of CREB1, a transcription factor that drives KSHV lytic gene expression. These studies provided a proof-of-principle application of a polypharmacology-based kinome screen for the study of KSHV reactivation and enabled the discovery of both kinase inhibitors and specific kinases that regulate the KSHV latent-to-lytic replication switch. Author Summary Kaposi's sarcoma-associated herpesvirus (KSHV) causes Kaposi's sarcoma, a cancer particularly prevalent in Africa. In cancer cells, the virus persists in a quiescent form called latency, in which only a few viral genes are made. Periodically, the virus switches into an active replicative cycle in which most of the viral genes are made and new virus is produced. What controls the switch from latency to active replication is not well understood, but cellular kinases, enzymes that control many cellular processes, have been implicated. Using a cell culture model of KSHV reactivation along with an innovative screening method that probes the effects of many cellular kinases simultaneously, we identified drugs that significantly limit KSHV reactivation, as well as specific kinases that either enhance or restrict KSHV replicative cycle. Among these were the ERBB kinases which are known to regulate growth of cancer cells. Understanding how these and other kinases contribute to the switch leading to production of more infectious virus helps us understand the mediators and mechanisms of KSHV diseases. Additionally, because kinase inhibitors are proving to be effective for treating other diseases including some cancers, identifying ones that restrict KSHV replicative cycle may lead to new approaches to treating KSHV-related diseases.
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Affiliation(s)
- Annabel T. Olson
- Division of Human Biology, Fred Hutchinson Cancer Center, University of Washington, Seattle, WA, USA
| | - Yuqi Kang
- Division of Human Biology, Fred Hutchinson Cancer Center, University of Washington, Seattle, WA, USA
| | - Anushka M. Ladha
- Department of Microbiology, University of Washington, Seattle, WA, USA
| | - Chuan Bian Lim
- Division of Human Biology, Fred Hutchinson Cancer Center, University of Washington, Seattle, WA, USA
| | - Michael Lagunoff
- Department of Microbiology, University of Washington, Seattle, WA, USA
| | - Taran S. Gujral
- Division of Human Biology, Fred Hutchinson Cancer Center, University of Washington, Seattle, WA, USA
- Department of Pharmacology, University of Washington, Seattle, WA, USA
| | - Adam P. Geballe
- Division of Human Biology, Fred Hutchinson Cancer Center, University of Washington, Seattle, WA, USA
- Division of Clinical Research, Fred Hutchinson Cancer Center, University of Washington, Seattle, WA, USA
- Department of Microbiology, University of Washington, Seattle, WA, USA
- Department of Medicine, University of Washington, Seattle, WA, USA
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8
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Li X, Wang F, Zhang X, Sun Q, Kuang E. Suppression of KSHV lytic replication and primary effusion lymphoma by selective RNF5 inhibition. PLoS Pathog 2023; 19:e1011103. [PMID: 36656913 PMCID: PMC9888681 DOI: 10.1371/journal.ppat.1011103] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 01/31/2023] [Accepted: 01/06/2023] [Indexed: 01/20/2023] Open
Abstract
Primary effusion lymphoma (PEL), a rare aggressive B-cell lymphoma in immunosuppressed patients, is etiologically associated with oncogenic γ-herpesvirus infection. Chemotherapy is commonly used to treat PEL but usually results in poor prognosis and survival; thus, novel therapies and drug development are urgently needed for PEL treatment. Here, we demonstrated that inhibition of Ring finger protein 5 (RNF5), an ER-localized E3 ligase, suppresses multiple cellular pathways and lytic replication of Kaposi sarcoma-associated herpesvirus (KSHV) in PEL cells. RNF5 interacts with and induces Ephrin receptors A3 (EphA3) and EphA4 ubiquitination and degradation. RNF5 inhibition increases the levels of EphA3 and EphA4, thereby reducing ERK and Akt activation and KSHV lytic replication. RNF5 inhibition decreased PEL xenograft tumor growth and downregulated viral gene expression, cell cycle gene expression, and hedgehog signaling in xenograft tumors. Our study suggests that RNF5 plays the critical roles in KSHV lytic infection and tumorigenesis of primary effusion lymphoma.
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Affiliation(s)
- Xiaojuan Li
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
- College of Clinical Medicine, Hubei University of Chinese Medicine, Wuhan, China
| | - Fan Wang
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Xiaolin Zhang
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Qinqin Sun
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Ersheng Kuang
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
- Key Laboratory of Tropical Disease Control (Sun Yat-Sen University), Ministry of Education, Guangzhou, China
- * E-mail:
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9
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Wang Y, Xu S, Han C, Huang Y, Wei J, Wei S, Qin Q. Modulatory effects of curcumin on Singapore grouper iridovirus infection-associated apoptosis and autophagy in vitro. FISH & SHELLFISH IMMUNOLOGY 2022; 131:84-94. [PMID: 36206994 DOI: 10.1016/j.fsi.2022.09.074] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 09/30/2022] [Accepted: 09/30/2022] [Indexed: 06/16/2023]
Abstract
Singapore grouper iridovirus (SGIV) with high pathogenicity can cause great economic losses to aquaculture industry. Thus, it is of urgency to find effective antiviral strategies to combat SGIV. Curcumin has been demonstrated effective antiviral activity on SGIV infection. However, the molecular mechanism behind this action needs to be further explanations. In view of the fact that apoptosis (type I programmed cell death) and autophagy (type II programmed cell death) were key regulators during SGIV infection, we aimed to investigate the relevance between antiviral activity of curcumin and SGIV-associated programmed and clarify the role of potential signaling pathways. Our results showed that curcumin suppressed SGIV-induced apoptosis. At the same time, the activities of caspase-3/8/9 and activating protein-1 (AP-1), P53, nuclear factor-κB (NF-ΚB) promoters were inhibited. Besides, the activation of extracellular regulated protein kinases (ERK), c-Jun N-terminal kinase (JNK) and p38 mitogen activate protein kinase (p38 MAPK) signal pathways were suppressed in curcumin-treated cells. On the other hand, curcumin down-regulated protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway to promote autophagy representing by increased LC3 II and Beclin1 expression. Curcumin also hindered the transition of cells from G1 to S phase, as well as down-regulating the expression of CyclinD1. Our findings revealed the resistance curcumin induced to the effects of DNA virus on cell apoptosis and autophagy and the insights gained from this study may be of assistance to understand the molecular mechanism of curcumin against DNA virus infection.
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Affiliation(s)
- Yuexuan Wang
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Suifeng Xu
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Chengzong Han
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Youhua Huang
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Jingguang Wei
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Shina Wei
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China.
| | - Qiwei Qin
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China; Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai, 528478, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266000, China.
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10
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Rusu-Zota G, Manole OM, Galeș C, Porumb-Andrese E, Obadă O, Mocanu CV. Kaposi Sarcoma, a Trifecta of Pathogenic Mechanisms. Diagnostics (Basel) 2022; 12:1242. [PMID: 35626397 PMCID: PMC9140574 DOI: 10.3390/diagnostics12051242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 04/29/2022] [Accepted: 05/13/2022] [Indexed: 01/10/2023] Open
Abstract
Kaposi's sarcoma is a rare disease with four known variants: classic, epidemic, endemic and iatrogenic (transplant-related), all caused by an oncogenic virus named Human Herpes Virus 8. The viral infection in itself, along with the oncogenic properties of HHV8 and with immune system dysfunction, forms the grounds on which Kaposi's Sarcoma may develop. Infection with HHV8 occurs through saliva via close contacts, blood, blood products, solid organ donation and, rarely, vertical transmission. Chronic inflammation and oncogenesis are promoted by a mix of viral genes that directly promote cell survival and transformation or interfere with the regular cell cycle and cell signaling (of particular note: LANA-1, v-IL6, vBCL-2, vIAP, vIRF3, vGPCR, gB, K1, K8.1, K15). The most common development sites for Kaposi's sarcoma are the skin, mucocutaneous zones, lymph nodes and visceral organs, but it can also rarely appear in the musculoskeletal system, urinary system, endocrine organs, heart or eye. Histopathologically, spindle cell proliferation with slit-like vascular spaces, plasma cell and lymphocyte infiltrate are characteristic. The clinical presentation is heterogenic depending on the variant; some patients have indolent disease and others have aggressive disease. The treatment options include highly active antiretroviral therapy, surgery, radiation therapy, chemotherapy, and immunotherapy. A literature search was carried out using the MEDLINE/PubMed, SCOPUS and Google Scholar databases with a combination of keywords with the aim to provide critical, concise, and comprehensive insights into advances in the pathogenic mechanism of Kaposi's sarcoma.
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Affiliation(s)
- Gabriela Rusu-Zota
- Department of Pharmacology, Clinical Pharmacology and Algesiology, Faculty of Medicine, University of Medicine and Pharmacy “Grigore T. Popa” Iasi, 700115 Iasi, Romania;
| | - Oana Mădălina Manole
- Faculty of Medicine, University of Medicine and Pharmacy “Grigore T. Popa” Iasi, 700115 Iasi, Romania
| | - Cristina Galeș
- Department of Histology, University of Medicine and Pharmacy “Grigore T. Popa” Iasi, 700115 Iasi, Romania;
| | - Elena Porumb-Andrese
- Department of Dermatology, University of Medicine and Pharmacy “Grigore T. Popa” Iasi, 700115 Iasi, Romania;
| | - Otilia Obadă
- Department of Ophthalmology, University of Medicine and Pharmacy “Grigore T. Popa” Iasi, 700115 Iasi, Romania;
| | - Cezar Valentin Mocanu
- Department of Anatomical Pathology, University of Medicine and Pharmacy “Grigore T. Popa” Iasi, 700115 Iasi, Romania;
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11
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Sandhu PK, Damania B. The regulation of KSHV lytic reactivation by viral and cellular factors. Curr Opin Virol 2022; 52:39-47. [PMID: 34872030 PMCID: PMC8844089 DOI: 10.1016/j.coviro.2021.11.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 11/03/2021] [Indexed: 02/03/2023]
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) is an oncogenic herpesvirus that exhibits two distinct phases of infection in the host-latent and lytic. The quiescent latent phase is defined by limited expression of a subset of viral proteins and microRNAs, and an absence of virus production. KSHV periodically reactivates from latency to undergo active lytic replication, leading to production of new infectious virions. This switch from the latent to the lytic phase requires the viral protein regulator of transcription activator (RTA). RTA, along with other virally encoded proteins, is aided by host factors to facilitate this transition. Herein, we highlight the key host proteins that are involved in mediating RTA activation and KSHV lytic replication and discuss the cellular processes in which they function. We will also focus on the modulation of viral reactivation by the innate immune system, and how KSHV influences key immune signaling pathways to aid its own lifecycle.
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Affiliation(s)
- Praneet Kaur Sandhu
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Department of Microbiology and Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Blossom Damania
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Department of Microbiology and Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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12
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Kang SK, Lee MJ, Ryu HH, Lee J, Lee MS. Dimethyl Sulfoxide Enhances Kaposi’s Sarcoma-Associated Herpesvirus Production During Lytic Replication. Front Microbiol 2021; 12:778525. [PMID: 34975802 PMCID: PMC8716793 DOI: 10.3389/fmicb.2021.778525] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 11/19/2021] [Indexed: 02/05/2023] Open
Abstract
Kaposi’s sarcoma-associated herpesvirus (KSHV) is an etiologic agent of Kaposi’s sarcoma, primary effusion lymphoma, and multicentric Castleman disease. In studies of KSHV, efficient virus production and isolation are essential. Reactivation of KSHV can be initiated by treating latently infected cells with chemicals, such as 12-O-tetradecanoyl-phorbol-13-acetate and sodium butyrate. These chemicals have been used as tools to induce lytic replication and viral production in KSHV-producing cell lines. Dimethyl sulfoxide (DMSO) is an organosulfur compound that is frequently used as an aprotic solvent similar to water. In experiments exploring signaling pathways in KSHV-infected cells, DMSO treatment alone as a vehicle affected the lytic gene expression of KSHV. However, to the best of our knowledge, the effects of DMSO on KSHV-producing cells have not yet been reported. Therefore, in this study, we investigated whether DMSO could be used as a reagent to enhance viral production during lytic replication in KSHV-producing cells and assessed the underlying mechanisms. The effects of DMSO on KSHV production were analyzed in iSLK BAC16 cells, which have been widely used for recombinant KSHV production. We found that the production of KSHV virions was significantly increased by treatment with DMSO during the induction of lytic replication. Mechanistically, lytic genes of KSHV were enhanced by DMSO treatment, which was correlated with virion production. Additionally, DMSO induced the phosphorylation of JNK during lytic replication, and inhibition of JNK abolished the effects of DMSO on lytic replication and virion production. Our findings showed that additional treatment with DMSO during the induction of lytic replication significantly improved the yield of KSHV production.
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Affiliation(s)
- Su-Kyung Kang
- Department of Microbiology and Immunology, Eulji University School of Medicine, Daejeon, South Korea
| | - Myung-Ju Lee
- Department of Microbiology and Immunology, Eulji University School of Medicine, Daejeon, South Korea
| | - Ho-Hyun Ryu
- Department of Microbiology and Immunology, Eulji University School of Medicine, Daejeon, South Korea
| | - Jisu Lee
- Department of Microbiology and Immunology, Eulji University School of Medicine, Daejeon, South Korea
| | - Myung-Shin Lee
- Department of Microbiology and Immunology, Eulji University School of Medicine, Daejeon, South Korea
- Eulji Biomedical Science Research Institute, Eulji University School of Medicine, Daejeon, South Korea
- *Correspondence: Myung-Shin Lee,
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13
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Markazi A, Meng W, Bracci PM, McGrath MS, Gao SJ. The Role of Bacteria in KSHV Infection and KSHV-Induced Cancers. Cancers (Basel) 2021; 13:cancers13174269. [PMID: 34503079 PMCID: PMC8428360 DOI: 10.3390/cancers13174269] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Revised: 08/05/2021] [Accepted: 08/19/2021] [Indexed: 12/12/2022] Open
Abstract
Simple Summary The aim of this article is to review the complex interactions of bacteria with Kaposi’s sarcoma-associated herpesvirus (KSHV) infection and KSHV-induced cancers. KSHV is causally associated with multiple cancers including Kaposi’s sarcoma (KS) and primary effusion lymphoma. Among patients coinfected by HIV and KSHV, patients with KS have a distinct oral microbiome compared to patients without KS. Moreover, KSHV patients have increased levels of salivary bacterial pathogen-associated molecular patterns compared to KSHV-negative patients. KSHV-associated bacterial species can increase KSHV replication and dissemination, and enhance cell proliferation of KSHV-transformed cells. The analysis of bacterial biomarkers associated with KSHV may help improve our understanding of the mechanisms driving KSHV-induced oncogenesis and identify novel targets for improving therapies of KSHV-related cancers. Abstract The objective of this article is to review the current status of the bacteria-virus interplay in Kaposi’s sarcoma-associated herpesvirus (KSHV) infection and KSHV-driven cancers. KSHV is the etiological agent of several cancers, including Kaposi’s sarcoma (KS) and primary effusion lymphoma. Due to immunosuppression, patients with KSHV are at an increased risk for bacterial infections. Moreover, among patients coinfected by HIV and KSHV, patients with KS have distinct oral microbiota compared to non-KS patients. Bacterial biomarkers associated with KSHV-driven cancers can provide insights in discerning the mechanisms of KSHV-induced oncogenesis. For example, pathogen-associated molecular patterns and bacterial products of certain bacterial species can regulate the expression of KSHV lytic and latent genes, thereby affecting viral replication and dissemination. In addition, infection with distinct opportunistic bacterial species have been associated with increased cell proliferation and tumorigenesis in KSHV-induced cancers through activation of pro-survival and -mitogenic cell signaling pathways. By elucidating the various mechanisms in which bacteria affect KSHV-associated pathogenesis, we will be able to pinpoint therapeutic targets for KSHV infection and KSHV-related cancers.
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Affiliation(s)
- Ashley Markazi
- Cancer Virology Program, UPMC Hillman Cancer Center, Pittsburgh, PA 15213, USA; (A.M.); (W.M.)
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA
| | - Wen Meng
- Cancer Virology Program, UPMC Hillman Cancer Center, Pittsburgh, PA 15213, USA; (A.M.); (W.M.)
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA
| | - Paige M. Bracci
- Department of Epidemiology and Biostatistics, University of California at San Francisco, San Francisco, CA 94158, USA;
| | - Michael S. McGrath
- Department of Laboratory Medicine, Pathology and Medicine, University of California at San Francisco, San Francisco, CA 94143, USA;
| | - Shou-Jiang Gao
- Cancer Virology Program, UPMC Hillman Cancer Center, Pittsburgh, PA 15213, USA; (A.M.); (W.M.)
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA
- Correspondence:
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HMGB1 Knockout Decreases Kaposi's Sarcoma-Associated Herpesvirus Virion Production in iSLK BAC16 Cells by Attenuating Viral Gene Expression. J Virol 2021; 95:e0079921. [PMID: 34105998 DOI: 10.1128/jvi.00799-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Multiple host proteins affect the gene expression of Kaposi's sarcoma-associated herpesvirus (KSHV) during latent and lytic replication. High-mobility group box 1 (HMGB1) serves as a highly conserved chromosomal protein inside the cell and a prototypical damage-associated molecular pattern molecule outside the cell. HMGB1 has been shown to play a pathogenic role in viral infectious diseases and to regulate the lytic replication of KSHV. However, its functional effects on the KSHV life cycle in KSHV-infected cells have not been fully elucidated. Here, we explored the role of intracellular and extracellular HMGB1 in KSHV virion production by employing CRISPR/Cas9-mediated HMGB1 knockout in the KSHV-producing iSLK BAC16 cell line. Intracellular HMGB1 formed complexes with various proteins, and the abundance of HMGB1-interacting proteins changed during latent and lytic replication. Moreover, extracellular HMGB1 was found to enhance lytic replication by phosphorylating JNK. Of note, the expression of viral genes was attenuated during lytic replication in HMGB1 knockout iSLK BAC16 cells, with significantly decreased production of infectious virions compared to that of wild-type cells. Collectively, our results demonstrate that HMGB1 is an important cellular cofactor that affects the generation of infectious KSHV progeny during lytic replication. IMPORTANCE The high-mobility group box 1 (HMGB1) protein has many intra- and extracellular biological functions with an intricate role in various diseases. In certain viral infections, HMGB1 affects the viral life cycle and pathogenesis. In this study, we explored the effects of HMGB1 knockout on the production of Kaposi's sarcoma-associated herpesvirus (KSHV). HMGB1 knockout decreased virion production in KSHV-producing cells by decreasing the expression of viral genes. The processes by which HMGB1 affects KSHV production may occur inside or outside infected cells. For instance, several cellular and viral proteins interacted with intracellular HMGB1 in a nucleosomal complex, whereas extracellular HMGB1 induced JNK phosphorylation, thereby enhancing lytic replication. Our results suggest that both intracellular and extracellular HMGB1 are necessary for efficient KSHV replication. Thus, HMGB1 may represent an effective therapeutic target for the regulation of KSHV production.
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15
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KDM2B Overexpression Facilitates Lytic De Novo KSHV Infection by Inducing AP-1 Activity Through Interaction with the SCF E3 Ubiquitin Ligase Complex. J Virol 2021; 95:JVI.00331-21. [PMID: 33692209 PMCID: PMC8139688 DOI: 10.1128/jvi.00331-21] [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] [Indexed: 12/26/2022] Open
Abstract
It is still largely unknown what host factors are involved in controlling the expression of the lytic viral gene RTA during primary infection, which determines if Kaposi's sarcoma-associated herpesvirus (KSHV) establishes latent or lytic infection. We have recently identified the histone demethylase KDM2B as a repressor of RTA expression during both de novo KSHV infection and latency based on an epigenetic factor siRNA screen. Here, we report that surprisingly, KDM2B overexpression can promote lytic de novo infection by using a mechanism that differs from what is needed for its repressor function. Our study revealed that while the DNA-binding and demethylase activities of KDM2B linked to its transcription repressive function are dispensable, its C-terminal F-box and LRR domains are required for the lytic infection-inducing function of KDM2B. We found that overexpressed KDM2B increases the half-life of the AP-1 subunit c-Jun protein and induces the AP-1 signaling pathway. This effect is dependent upon the binding of KDM2B to the SKP1-CUL1-F-box (SCF) E3 ubiquitin ligase complex via its F-box domain. Importantly, the inhibition of AP-1 reduces KDM2B-mediated lytic de novo KSHV infection. Overall, our findings indicate that KDM2B may induce the degradation of some host factors by using the SCF complex resulting in the enrichment of c-Jun. This leads to increased AP-1 transcriptional activity, which facilitates lytic gene expression following de novo infection interfering with the establishment of viral latency.SignificanceThe expression of epigenetic factors is often dysregulated in cancers or upon specific stress signals, which often results in a display of non-canonical functions of the epigenetic factors that are independent from their chromatin-modifying roles. We have previously demonstrated that KDM2B normally inhibits KSHV lytic cycle using its histone demethylase activity. Surprisingly, we found that KDM2B overexpression can promote lytic de novo infection, which does not require its histone demethylase or DNA-binding functions. Instead, KDM2B uses the SKP1-CUL1-F-box (SCF) E3 ubiquitin ligase complex to induce AP-1 transcriptional activity, which promotes lytic gene expression. This is the first report that demonstrates a functional link between SFCKDM2B and AP-1 in the regulation of KSHV lytic cycle.
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16
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Mohanta TK, Sharma N, Arina P, Defilippi P. Molecular Insights into the MAPK Cascade during Viral Infection: Potential Crosstalk between HCQ and HCQ Analogues. BIOMED RESEARCH INTERNATIONAL 2020; 2020:8827752. [PMID: 33426074 PMCID: PMC7780227 DOI: 10.1155/2020/8827752] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 12/09/2020] [Accepted: 12/17/2020] [Indexed: 12/21/2022]
Abstract
The mitogen-activated protein kinase (MAPK) pathway links the cell-surface receptors to the transcription machinery, transducing the extracellular signals into several outputs, which may also adapt the host defense mechanism to viral attacks. The Severe Acute Respiratory Syndrome CoronaVirus 2 (SARS-CoV-2) that causes the COrona VIrus Disease 2019 (COVID-19) has infected upwards of nearly 70 million people and worldwide has claimed more than 1,600,000 deaths. So far, there continues to be no specific treatment for this novel coronavirus-induced disease. In the search to control the global COVID-19 pandemic, some eastern and developing countries have approved a variety of treatments with controversial efficacy, among which is the use of the antimalarial hydroxychloroquine (HCQ). Interestingly, prior data had indicated that the HCQ/CQ could influence the MAPK cascade. The main aim of this review is to address molecular mechanisms, beyond drugs, that can be helpful against viral infection for this and future pandemics. We will highlight (1) the contribution of the MAPK cascade in viral infection and (2) the possible use of MAPK inhibitors in curbing viral infections, alone or in combination with HCQ and quinoline analogues. We are convinced that understanding the molecular patterns of viral infections will be critical for new therapeutical approaches to control this and other severe diseases.
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Affiliation(s)
- Tapan Kumar Mohanta
- Natural and Medical Sciences Research Center, University of Nizwa, Nizwa 616, Oman
| | - Nanaocha Sharma
- Institute of Bioresources and Sustainable Development (IBSD), Imphal 795001, India
| | - Pietro Arina
- UCL Division of Medicine, Bloomsbury Institute for Intensive Care Medicine, London, WC1E 6BT, UK
| | - Paola Defilippi
- Department of Molecular Biotechnology and Health Sciences, University of Turin, Turin 10126, Italy
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Dai L, Barrett L, Plaisance-Bonstaff K, Post SR, Qin Z. Porphyromonas gingivalis coinfects with KSHV in oral cavities of HIV+ patients and induces viral lytic reactivation. J Med Virol 2020; 92:3862-3867. [PMID: 32436999 PMCID: PMC7679274 DOI: 10.1002/jmv.26028] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 05/14/2020] [Accepted: 05/15/2020] [Indexed: 11/06/2022]
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) infection causes several human cancers, including Kaposi's sarcoma (KS), one of the most common AIDS-associated tumors. The involvement of the oral cavity represents one common clinical manifestation of AIDS-KS individuals with periodontal diseases and an oral carriage of a variety of pathogenic bacteria, including Porphyromonas gingivalis. In the current study, we report the clinical relevance of P. gingivalis and KSHV coinfection in the oral cavity of a cohort of HIV+ patients. Furthermore, we found that P. gingivalis conditioned medium or derived lipopolysaccharide effectively induced KSHV lytic reactivation from infected oral cells. This reactivation requires TLR4 as well as the activities of p38 and Jun N-terminal kinase- mitogen-activated protein kinase signaling pathways. Our findings reveal the mechanisms through which coinfected periodontal pathogens potentially promote oncogenic virus pathogenesis in the unique niche of immunocompromised patients.
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Affiliation(s)
- Lu Dai
- Department of Pathology, Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, 4301 W Markham St, Little Rock, AR 72205, USA
| | - Lindsey Barrett
- Department of Pathology, Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, 4301 W Markham St, Little Rock, AR 72205, USA
| | - Karlie Plaisance-Bonstaff
- Departments of Medicine, Louisiana State University Health Sciences Center, Louisiana Cancer Research Center, 1700 Tulane Ave., New Orleans, LA 70112, USA
| | - Steven R. Post
- Department of Pathology, Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, 4301 W Markham St, Little Rock, AR 72205, USA
| | - Zhiqiang Qin
- Department of Pathology, Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, 4301 W Markham St, Little Rock, AR 72205, USA
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Pseudomonas aeruginosa Stimulates Inflammation and Enhances Kaposi's Sarcoma Herpesvirus-Induced Cell Proliferation and Cellular Transformation through both Lipopolysaccharide and Flagellin. mBio 2020; 11:mBio.02843-20. [PMID: 33173008 PMCID: PMC7667028 DOI: 10.1128/mbio.02843-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Inflammation triggered by innate immunity promotes carcinogenesis in cancer. Kaposi's sarcoma (KS), a hyperproliferative and inflammatory tumor caused by Kaposi's sarcoma-associated herpesvirus (KSHV) infection, is the most common cancer in AIDS patients. KSHV infection sensitizes cells to pathogen-associated molecular patterns (PAMPs). We examined the role of Pseudomonas aeruginosa, an opportunistic bacterium that can affect AIDS patients, in inflammation and cell proliferation of KSHV-transformed cells. P. aeruginosa stimulation increased cell proliferation and efficiency of colony formation in soft agar of KSHV-transformed rat primary mesenchymal precursor (KMM) cells but had no significant effect on the untransformed (MM) cells. P. aeruginosa stimulation also increased cell proliferation of KSHV-infected human B cells, BJAB, but not the uninfected cells. Mechanistically, P. aeruginosa stimulation resulted in increased inflammatory cytokines and activation of p38, ERK1/2, and JNK mitogen-activated protein kinase (MAPK) pathways in KMM cells while having no obvious effect on MM cells. P. aeruginosa induction of inflammation and MAPKs was observed with and without inhibition of the Toll-like receptor 4 (TLR4) pathway, while a flagellin-deleted mutant of P. aeruginosa required a functional TLR4 pathway to induce inflammation and MAPKs. Furthermore, treatment with either lipopolysaccharide (LPS) or flagellin alone was sufficient to induce inflammatory cytokines, activate MAPKs, and increase cell proliferation and efficiency of colony formation in soft agar of KMM cells. These results demonstrate that both LPS and flagellin are PAMPs that contribute to P. aeruginosa induction of inflammation in KSHV-transformed cells. Because AIDS-KS patients are susceptible to P. aeruginosa infection, our work highlights the preventive and therapeutic potential of targeting P. aeruginosa infection in these patients.IMPORTANCE Kaposi's sarcoma (KS), caused by infection with Kaposi's sarcoma-associated herpesvirus (KSHV), is one of the most common cancers in AIDS patients. KS is a highly inflammatory tumor, but how KSHV infection induces inflammation remains unclear. We have previously shown that KSHV infection upregulates Toll-like receptor 4 (TLR4), sensitizing cells to lipopolysaccharide (LPS) and Escherichia coli In the current study, we examined the role of Pseudomonas aeruginosa, an opportunistic bacterium that can affect AIDS patients, in inflammation and cell proliferation of KSHV-transformed cells. P. aeruginosa stimulation increased cell proliferation, inflammatory cytokines, and activation of growth and survival pathways in KSHV-transformed cells through two pathogen-associated molecular patterns, LPS and flagellin. Because AIDS-KS patients are susceptible to P. aeruginosa infection, our work highlights the preventive and therapeutic potential of targeting P. aeruginosa infection in these patients.
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Regulation of KSHV Latency and Lytic Reactivation. Viruses 2020; 12:v12091034. [PMID: 32957532 PMCID: PMC7551196 DOI: 10.3390/v12091034] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 09/10/2020] [Accepted: 09/12/2020] [Indexed: 02/06/2023] Open
Abstract
Kaposi’s sarcoma-associated herpesvirus (KSHV) is associated with three malignancies— Kaposi’s sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman’s disease (MCD). Central to the pathogenesis of these diseases is the KSHV viral life cycle, which is composed of a quiescent latent phase and a replicative lytic phase. While the establishment of latency enables persistent KSHV infection and evasion of the host immune system, lytic replication is essential for the dissemination of the virus between hosts and within the host itself. The transition between these phases, known as lytic reactivation, is controlled by a complex set of environmental, host, and viral factors. The effects of these various factors converge on the regulation of two KSHV proteins whose functions facilitate each phase of the viral life cycle—latency-associated nuclear antigen (LANA) and the master switch of KSHV reactivation, replication and transcription activator (RTA). This review presents the current understanding of how the transition between the phases of the KSHV life cycle is regulated, how the various phases contribute to KSHV pathogenesis, and how the viral life cycle can be exploited as a therapeutic target.
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20
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Sperm associated antigen 9 promotes oncogenic KSHV-encoded interferon regulatory factor-induced cellular transformation and angiogenesis by activating the JNK/VEGFA pathway. PLoS Pathog 2020; 16:e1008730. [PMID: 32776977 PMCID: PMC7446834 DOI: 10.1371/journal.ppat.1008730] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 08/20/2020] [Accepted: 06/21/2020] [Indexed: 12/12/2022] Open
Abstract
Kaposi's sarcoma (KS), caused by Kaposi's sarcoma-associated herpesvirus (KSHV), is a highly angioproliferative disseminated tumor of endothelial cells commonly found in AIDS patients. We have recently shown that KSHV-encoded viral interferon regulatory factor 1 (vIRF1) mediates KSHV-induced cell motility (PLoS Pathog. 2019 Jan 30;15(1):e1007578). However, the role of vIRF1 in KSHV-induced cellular transformation and angiogenesis remains unknown. Here, we show that vIRF1 promotes angiogenesis by upregulating sperm associated antigen 9 (SPAG9) using two in vivo angiogenesis models including the chick chorioallantoic membrane assay (CAM) and the matrigel plug angiogenesis assay in mice. Mechanistically, vIRF1 interacts with transcription factor Lef1 to promote SPAG9 transcription. vIRF1-induced SPAG9 promotes the interaction of mitogen-activated protein kinase kinase 4 (MKK4) with JNK1/2 to increase their phosphorylation, resulting in enhanced VEGFA expression, angiogenesis, cell proliferation and migration. Finally, genetic deletion of ORF-K9 from KSHV genome abolishes KSHV-induced cellular transformation and impairs angiogenesis. Our results reveal that vIRF1 transcriptionally activates SPAG9 expression to promote angiogenesis and tumorigenesis via activating JNK/VEGFA signaling. These novel findings define the mechanism of KSHV induction of the SPAG9/JNK/VEGFA pathway and establish the scientific basis for targeting this pathway for treating KSHV-associated cancers.
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Liu Y, Zhu J, Guo X, Huang T, Han J, Gao J, Xu D, Han W. How oncogenic mutations activate human MAP kinase 1 (MEK1): a molecular dynamics simulation study. J Biomol Struct Dyn 2020; 38:3942-3958. [PMID: 31658877 PMCID: PMC8177546 DOI: 10.1080/07391102.2019.1686065] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 07/19/2019] [Accepted: 09/10/2019] [Indexed: 01/03/2023]
Abstract
Approximately 30% of all types of human cancers possess a constitutively activated the mitogen-activated protein kinase (MAPK) signaling pathway while MAP kinase 1 (MEK1) is a critical component of this pathway. It has been reported mutations could improve the activity of MEK1 to result in cell proliferation and transformation, which is a known oncogenic event in various cancer types. In this study, eight molecular dynamics simulations, molecular mechanics Poisson-Boltzmann surface area (MM-PBSA), combined with protein structure network were performed to explore the mechanism that mutations activate MEK1. Protein structure networks and hydrogen bonds analysis demonstrated that active mutations broke the interaction between activation segments (residues 216-222) and C-helix (residues 105-121) in MEK1, leading to it transform inactive form to active form. Moreover, hydrogen bond analysis and MM-PBSA calculation indicated that activating mutations decrease the binding affinity between MEK1 and inhibitor to reduce the inhibitory effect of inhibitors. In addition, some active mutations cause structural changes in the Pro-rich loop (residues 261-268) of MEK1. These changes may stabilize the interaction between the MEK1 mutants and the ligands by increasing the number of exposed hydrophobic residues in the active site of MEK1. Our results may provide useful theoretical evidences for the mechanism underlying the role of human MEK1 in human cancers.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Ye Liu
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, School of Life Science, Jilin University, Changchun, China
| | - Jingxuan Zhu
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, School of Life Science, Jilin University, Changchun, China
| | - Xiaoqing Guo
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, School of Life Science, Jilin University, Changchun, China
| | - Tianci Huang
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, School of Life Science, Jilin University, Changchun, China
| | - Jiarui Han
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, School of Life Science, Jilin University, Changchun, China
| | - Jianjiong Gao
- Marie-Josée and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Dong Xu
- Department of Electric Engineering and Computer Science, C.S. Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
- College of Computer Science and Technology, Jilin University, Changchun, China
| | - Weiwei Han
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, School of Life Science, Jilin University, Changchun, China
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22
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Fiches GN, Zhou D, Kong W, Biswas A, Ahmed EH, Baiocchi RA, Zhu J, Santoso N. Profiling of immune related genes silenced in EBV-positive gastric carcinoma identified novel restriction factors of human gammaherpesviruses. PLoS Pathog 2020; 16:e1008778. [PMID: 32841292 PMCID: PMC7473590 DOI: 10.1371/journal.ppat.1008778] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 09/04/2020] [Accepted: 07/05/2020] [Indexed: 12/24/2022] Open
Abstract
EBV-associated gastric cancer (EBVaGC) is characterized by high frequency of DNA methylation. In this study, we investigated how epigenetic alteration of host genome contributes to pathogenesis of EBVaGC through the analysis of transcriptomic and epigenomic datasets from NIH TCGA (The Cancer Genome Atlas) consortium. We identified that immune related genes (IRGs) is a group of host genes preferentially silenced in EBV-positive gastric cancers through DNA hypermethylation. Further functional characterizations of selected IRGs reveal their novel antiviral activity against not only EBV but also KSHV. In particular, we showed that metallothionein-1 (MT1) and homeobox A (HOXA) gene clusters are down-regulated via EBV-driven DNA hypermethylation. Several MT1 isoforms suppress EBV lytic replication and release of progeny virions as well as KSHV lytic reactivation, suggesting functional redundancy of these genes. In addition, single HOXA10 isoform exerts antiviral activity against both EBV and KSHV. We also confirmed the antiviral effect of other dysregulated IRGs, such as IRAK2 and MAL, in scenario of EBV and KSHV lytic reactivation. Collectively, our results demonstrated that epigenetic silencing of IRGs is a viral strategy to escape immune surveillance and promote viral propagation, which is overall beneficial to viral oncogenesis of human gamma-herpesviruses (EBV and KSHV), considering that these IRGs possess antiviral activities against these oncoviruses.
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Affiliation(s)
- Guillaume N. Fiches
- Department of Pathology, Ohio State University College of Medicine, Columbus, Ohio, United States of America
| | - Dawei Zhou
- Department of Pathology, Ohio State University College of Medicine, Columbus, Ohio, United States of America
| | - Weili Kong
- Gladstone Institute of Virology and Immunology, University of California, San Francisco, California, United States of America
| | - Ayan Biswas
- Department of Pathology, Ohio State University College of Medicine, Columbus, Ohio, United States of America
| | - Elshafa H. Ahmed
- Division of Hematology, Department of Internal Medicine, Ohio State University College of Medicine, Columbus, Ohio, United States of America
| | - Robert A. Baiocchi
- Division of Hematology, Department of Internal Medicine, Ohio State University College of Medicine, Columbus, Ohio, United States of America
| | - Jian Zhu
- Department of Pathology, Ohio State University College of Medicine, Columbus, Ohio, United States of America
| | - Netty Santoso
- Department of Pathology, Ohio State University College of Medicine, Columbus, Ohio, United States of America
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23
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Liu S, Chu B, Cai C, Wu X, Yao W, Wu Z, Yang Z, Li F, Liu Y, Dong P, Gong W. DGCR5 Promotes Gallbladder Cancer by Sponging MiR-3619-5p via MEK/ERK1/2 and JNK/p38 MAPK Pathways. J Cancer 2020; 11:5466-5477. [PMID: 32742494 PMCID: PMC7391188 DOI: 10.7150/jca.46351] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 06/15/2020] [Indexed: 02/05/2023] Open
Abstract
Gallbladder cancer (GBC) is a highly aggressive malignant cancer with poor prognosis. Long noncoding RNA (lncRNA) DiGeorge syndrome critical region gene (DGCR5) has been reported to participate in various types of cancers, but its role in GBC remains largely unknown. This study aimed to explore the functions and mechanisms of DGCR5 in GBC. Here, we found that DGCR5 was upregulated in GBC tissues and cell lines. Through functional experiments, it was demonstrated that silence of DGCR5 significantly suppressed the cell proliferation, migration, invasion, and induced apoptosis and cell cycle arrest in GBC cells. In addition, miR-3619-5p was predicted and further verified as the target of DGCR5. Moreover, miR-3619-5p was observed downregulated in GBC tissues and cell lines, and miR-3619-5p mimics repressed the GBC cell proliferation, migration, invasion and could be rescued by DGCR5 overexpression. Mechanistically, it was found that DGCR5 knockdown and miR-3619-5p mimics inactivated the MEK/ERK1/2 and JNK/p38 MAPK pathways. In addition, rescue experiments indicated that inhibition of MEK/ERK1/2 and JNK/p38 MAPK pathways could reverse the effects of DGCR5 overexpression on cell proliferation, migration and invasion. Finally, xenograft model assay was used to validate that knockdown of DGCR5 suppressed GBC via regulating MEK/ERK1/2 and JNK/p38 MAPK pathways in vivo. Taken together, it was uncovered in our study that DGCR5 exerts an oncogenic role by sponging miR-3619-5p and activating MEK/ERK1/2 and JNK/p38 MAPK pathways in GBC progression.
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Affiliation(s)
- Shilei Liu
- Department of General Surgery, Xinhua Hospital, Affiliated to Shanghai Jiao Tong University School of Medicine, No. 1665 Kongjiang Road, Shanghai 200092, China.,Shanghai Key Laboratory of Biliary Tract Disease Research, No. 1665 Kongjiang Road, Shanghai 200092, China
| | - Bingfeng Chu
- Department of General Surgery, Xinhua Hospital, Affiliated to Shanghai Jiao Tong University School of Medicine, No. 1665 Kongjiang Road, Shanghai 200092, China.,Shanghai Key Laboratory of Biliary Tract Disease Research, No. 1665 Kongjiang Road, Shanghai 200092, China
| | - Chen Cai
- Department of General Surgery, Xinhua Hospital, Affiliated to Shanghai Jiao Tong University School of Medicine, No. 1665 Kongjiang Road, Shanghai 200092, China.,Shanghai Key Laboratory of Biliary Tract Disease Research, No. 1665 Kongjiang Road, Shanghai 200092, China
| | - Xiangsong Wu
- Department of General Surgery, Xinhua Hospital, Affiliated to Shanghai Jiao Tong University School of Medicine, No. 1665 Kongjiang Road, Shanghai 200092, China.,Shanghai Key Laboratory of Biliary Tract Disease Research, No. 1665 Kongjiang Road, Shanghai 200092, China
| | - Wenyan Yao
- Department of General Surgery, Xinhua Hospital, Affiliated to Shanghai Jiao Tong University School of Medicine, No. 1665 Kongjiang Road, Shanghai 200092, China
| | - Ziyou Wu
- Department of General Surgery, Xinhua Hospital, Affiliated to Shanghai Jiao Tong University School of Medicine, No. 1665 Kongjiang Road, Shanghai 200092, China
| | - Ziyi Yang
- Department of General Surgery, Xinhua Hospital, Affiliated to Shanghai Jiao Tong University School of Medicine, No. 1665 Kongjiang Road, Shanghai 200092, China.,Shanghai Key Laboratory of Biliary Tract Disease Research, No. 1665 Kongjiang Road, Shanghai 200092, China
| | - Fengnan Li
- Department of General Surgery, Xinhua Hospital, Affiliated to Shanghai Jiao Tong University School of Medicine, No. 1665 Kongjiang Road, Shanghai 200092, China.,Shanghai Key Laboratory of Biliary Tract Disease Research, No. 1665 Kongjiang Road, Shanghai 200092, China
| | - Yingbin Liu
- Department of General Surgery, Xinhua Hospital, Affiliated to Shanghai Jiao Tong University School of Medicine, No. 1665 Kongjiang Road, Shanghai 200092, China.,Shanghai Key Laboratory of Biliary Tract Disease Research, No. 1665 Kongjiang Road, Shanghai 200092, China
| | - Ping Dong
- Department of General Surgery, Xinhua Hospital, Affiliated to Shanghai Jiao Tong University School of Medicine, No. 1665 Kongjiang Road, Shanghai 200092, China.,Shanghai Key Laboratory of Biliary Tract Disease Research, No. 1665 Kongjiang Road, Shanghai 200092, China
| | - Wei Gong
- Department of General Surgery, Xinhua Hospital, Affiliated to Shanghai Jiao Tong University School of Medicine, No. 1665 Kongjiang Road, Shanghai 200092, China.,Shanghai Key Laboratory of Biliary Tract Disease Research, No. 1665 Kongjiang Road, Shanghai 200092, China
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24
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Hiura K, Strahan R, Uppal T, Prince B, Rossetto CC, Verma SC. KSHV ORF59 and PAN RNA Recruit Histone Demethylases to the Viral Chromatin during Lytic Reactivation. Viruses 2020; 12:v12040420. [PMID: 32283586 PMCID: PMC7232192 DOI: 10.3390/v12040420] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Revised: 04/02/2020] [Accepted: 04/02/2020] [Indexed: 12/17/2022] Open
Abstract
Kaposi’s sarcoma-associated herpesvirus (KSHV) causes multiple malignancies in immunocompromised individuals. KSHV primarily establishes a lifelong latency in infected humans during which only a subset of viral genes is expressed while most of the viral genome remains transcriptionally silent with condensed chromatin. However, during the lytic phase, the viral genome undergoes dramatic changes in chromatin landscape leading to a transcriptionally active state with the expression of most of the viral genes and production of progeny virions. Multiple cellular and viral factors influence the epigenetic gene regulation and transitioning of virus from latency to the lytic state. We have earlier shown that KSHV ORF59, viral processivity factor, binds to a protein arginine methyl transferase 5 (PRMT5) to alter the histone arginine methylation during reactivation. Additionally, ORF59 has been shown to interact with most abundantly expressed KSHV long noncoding polyadenylated nuclear RNA (PAN RNA), which associates with the viral epigenome during reactivation. Interestingly, PAN RNA interacts with UTX and JMJD3, cellular H3K27me3 demethylases, and removes the repressive marks on the chromatin. In this study, we report that the recruitment of histone demethylases to the viral chromatin is facilitated by the expression of ORF59 protein and PAN RNA. Using biochemical and localization assays including co-immunoprecipitation and immunofluorescence, we demonstate ORF59 localizes with UTX and JMJD3. Our results confirm that PAN RNA enhances the interaction of ORF59 with the chromatin modifying enzymes UTX and JMJD3.
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25
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Wong JP, Stuhlmiller TJ, Giffin LC, Lin C, Bigi R, Zhao J, Zhang W, Bravo Cruz AG, Park SI, Earp HS, Dittmer DP, Frye SV, Wang X, Johnson GL, Damania B. Kinome profiling of non-Hodgkin lymphoma identifies Tyro3 as a therapeutic target in primary effusion lymphoma. Proc Natl Acad Sci U S A 2019; 116:16541-16550. [PMID: 31346082 PMCID: PMC6697815 DOI: 10.1073/pnas.1903991116] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Non-Hodgkin lymphomas (NHLs) make up the majority of lymphoma diagnoses and represent a very diverse set of malignancies. We sought to identify kinases uniquely up-regulated in different NHL subtypes. Using multiplexed inhibitor bead-mass spectrometry (MIB/MS), we found Tyro3 was uniquely up-regulated and important for cell survival in primary effusion lymphoma (PEL), which is a viral lymphoma infected with Kaposi's sarcoma-associated herpesvirus (KSHV). Tyro3 was also highly expressed in PEL cell lines as well as in primary PEL exudates. Based on this discovery, we developed an inhibitor against Tyro3 named UNC3810A, which hindered cell growth in PEL, but not in other NHL subtypes where Tyro3 was not highly expressed. UNC3810A also significantly inhibited tumor progression in a PEL xenograft mouse model that was not seen in a non-PEL NHL model. Taken together, our data suggest Tyro3 is a therapeutic target for PEL.
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Affiliation(s)
- Jason P Wong
- Department of Microbiology and Immunology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Timothy J Stuhlmiller
- Department of Pharmacology and Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599
| | - Louise C Giffin
- Department of Microbiology and Immunology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Carolina Lin
- Department of Microbiology and Immunology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Rachele Bigi
- Department of Microbiology and Immunology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
- Department of Microbiology and Immunology and Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Jichen Zhao
- Center for Integrative Chemical Biology and Drug Discovery, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
- Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Weihe Zhang
- Center for Integrative Chemical Biology and Drug Discovery, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
- Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Ariana G Bravo Cruz
- Department of Microbiology and Immunology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Steven I Park
- Department of Medicine and Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599
| | - H Shelton Earp
- Department of Medicine and Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599
| | - Dirk P Dittmer
- Department of Microbiology and Immunology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
- Department of Microbiology and Immunology and Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Stephen V Frye
- Center for Integrative Chemical Biology and Drug Discovery, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
- Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Xiaodong Wang
- Center for Integrative Chemical Biology and Drug Discovery, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599;
- Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Gary L Johnson
- Department of Pharmacology and Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC 27599;
| | - Blossom Damania
- Department of Microbiology and Immunology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599;
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DuShane JK, Maginnis MS. Human DNA Virus Exploitation of the MAPK-ERK Cascade. Int J Mol Sci 2019; 20:ijms20143427. [PMID: 31336840 PMCID: PMC6679023 DOI: 10.3390/ijms20143427] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 07/09/2019] [Accepted: 07/11/2019] [Indexed: 12/19/2022] Open
Abstract
The extracellular signal-regulated kinases (ERKs) comprise a particular branch of the mitogen-activated protein kinase cascades (MAPK) that transmits extracellular signals into the intracellular environment to trigger cellular growth responses. Similar to other MAPK cascades, the MAPK-ERK pathway signals through three core kinases—Raf, MAPK/ERK kinase (MEK), and ERK—which drive the signaling mechanisms responsible for the induction of cellular responses from extracellular stimuli including differentiation, proliferation, and cellular survival. However, pathogens like DNA viruses alter MAPK-ERK signaling in order to access DNA replication machineries, induce a proliferative state in the cell, or even prevent cell death mechanisms in response to pathogen recognition. Differential utilization of this pathway by multiple DNA viruses highlights the dynamic nature of the MAPK-ERK pathway within the cell and the importance of its function in regulating a wide variety of cellular fates that ultimately influence viral infection and, in some cases, result in tumorigenesis.
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Affiliation(s)
- Jeanne K DuShane
- Department of Molecular and Biomedical Sciences, The University of Maine, Orono, ME 04401, USA
| | - Melissa S Maginnis
- Department of Molecular and Biomedical Sciences, The University of Maine, Orono, ME 04401, USA.
- Graduate School in Biomedical Sciences and Engineering, The University of Maine, Orono, ME 04401, USA.
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27
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Yan L, Majerciak V, Zheng ZM, Lan K. Towards Better Understanding of KSHV Life Cycle: from Transcription and Posttranscriptional Regulations to Pathogenesis. Virol Sin 2019; 34:135-161. [PMID: 31025296 PMCID: PMC6513836 DOI: 10.1007/s12250-019-00114-3] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 03/14/2019] [Indexed: 02/08/2023] Open
Abstract
Kaposi’s sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus-8 (HHV-8), is etiologically linked to the development of Kaposi’s sarcoma, primary effusion lymphoma, and multicentric Castleman’s disease. These malignancies often occur in immunosuppressed individuals, making KSHV infection-associated diseases an increasing global health concern with persistence of the AIDS epidemic. KSHV exhibits biphasic life cycles between latent and lytic infection and extensive transcriptional and posttranscriptional regulation of gene expression. As a member of the herpesvirus family, KSHV has evolved many strategies to evade the host immune response, which help the virus establish a successful lifelong infection. In this review, we summarize the current research status on the biology of latent and lytic viral infection, the regulation of viral life cycles and the related pathogenesis.
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Affiliation(s)
- Lijun Yan
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Vladimir Majerciak
- National Cancer Institute, National Institutes of Health, Frederick, MD, 21702, USA
| | - Zhi-Ming Zheng
- National Cancer Institute, National Institutes of Health, Frederick, MD, 21702, USA.
| | - Ke Lan
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
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28
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Moriguchi M, Watanabe T, Kadota A, Fujimuro M. Capsaicin Induces Apoptosis in KSHV-Positive Primary Effusion Lymphoma by Suppressing ERK and p38 MAPK Signaling and IL-6 Expression. Front Oncol 2019; 9:83. [PMID: 30838176 PMCID: PMC6389641 DOI: 10.3389/fonc.2019.00083] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 01/29/2019] [Indexed: 01/28/2023] Open
Abstract
Primary effusion lymphoma (PEL) is defined as a rare subtype of non-Hodgkin's B-cell lymphoma which is caused by Kaposi's sarcoma-associated herpesvirus (KSHV) in immunosuppressed patients. PEL is an aggressive lymphoma and is frequently resistant to conventional chemotherapies. Therefore, it is critical to investigate novel therapeutic options for PEL. Capsaicin is a pungent component of chili pepper and possesses unique pharmacological effects, such as pain relief, anti-microbial and anti-cancer properties. Here, we demonstrate that capsaicin markedly inhibited the growth of KSHV latently infected PEL cells by inhibiting ERK, p38 MAPK and expression hIL-6, which are known to contribute to PEL growth and survival. The underlying mechanism of action by capsaicin was through the inhibition of ERK and p38 MAPK phosphorylation and signaling that affected hIL-6 expression. As a result, capsaicin induced apoptosis in PEL cells in a caspase-9 dependent manner. In line with these results, ERK (U0126) and p38 MAPK (SB203580) specific signaling inhibitors suppressed hIL-6 expression and attenuated cell growth in PEL cells. Furthermore, the addition of hIL-6 neutralizing antibody to culture medium suppressed the growth of PEL cells. We also demonstrate that capsaicin suppressed PEL cell growth in the absence of nascent viral replication. Finally, we confirmed ex vivo treatment of capsaicin attenuated PEL development in SCID mice. Taken together, capsaicin could represent a lead compound for PEL therapy without the risk of de novo KSHV infection.
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Affiliation(s)
- Misato Moriguchi
- Department of Cell Biology, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Tadashi Watanabe
- Department of Cell Biology, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Ayano Kadota
- Department of Cell Biology, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Masahiro Fujimuro
- Department of Cell Biology, Kyoto Pharmaceutical University, Kyoto, Japan
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29
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Gao R, Li T, Tan B, Ramos da Silva S, Jung JU, Feng P, Gao SJ. FoxO1 Suppresses Kaposi's Sarcoma-Associated Herpesvirus Lytic Replication and Controls Viral Latency. J Virol 2019; 93:JVI.01681-18. [PMID: 30404794 PMCID: PMC6340022 DOI: 10.1128/jvi.01681-18] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Accepted: 10/31/2018] [Indexed: 02/05/2023] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) has latent and lytic replication phases, both of which contribute to the development of KSHV-induced malignancies. Among the numerous factors identified to regulate the KSHV life cycle, oxidative stress, caused by imbalanced clearing and production of reactive oxygen species (ROS), has been shown to robustly disrupt KSHV latency and induce viral lytic replication. In this study, we identified an important role of the antioxidant defense factor forkhead box protein O1 (FoxO1) in the KSHV life cycle. Either chemical inhibition of the FoxO1 function or knockdown of FoxO1 expression led to an increase in the intracellular ROS level that was subsequently sufficient to disrupt KSHV latency and induce viral lytic reactivation. On the other hand, treatment with N-acetyl-l-cysteine (NAC), an oxygen free radical scavenger, led to a reduction in the FoxO1 inhibition-induced ROS level and, ultimately, the attenuation of KSHV lytic reactivation. These findings reveal that FoxO1 plays a critical role in keeping KSHV latency in check by maintaining the intracellular redox balance.IMPORTANCE Kaposi's sarcoma-associated herpesvirus (KSHV) is associated with several cancers, including Kaposi's sarcoma (KS). Both the KSHV latent and lytic replication phases are important for the development of KS. Identification of factors regulating the KSHV latent phase-to-lytic phase switch can provide insights into the pathogenesis of KSHV-induced malignancies. In this study, we show that the antioxidant defense factor forkhead box protein O1 (FoxO1) maintains KSHV latency by suppressing viral lytic replication. Inhibition of FoxO1 disrupts KSHV latency and induces viral lytic replication by increasing the intracellular ROS level. Significantly, treatment with an oxygen free radical scavenger, N-acetyl-l-cysteine (NAC), attenuated the FoxO1 inhibition-induced intracellular ROS level and KSHV lytic replication. Our works reveal a critical role of FoxO1 in suppressing KSHV lytic replication, which could be targeted for antiviral therapy.
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Affiliation(s)
- Ruoyun Gao
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Tingting Li
- UPMC Hillman Cancer Center, Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Brandon Tan
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Suzane Ramos da Silva
- UPMC Hillman Cancer Center, Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Jae U Jung
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Pinghui Feng
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Shou-Jiang Gao
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
- UPMC Hillman Cancer Center, Department of Microbiology and Molecular Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Laboratory of Human Virology and Oncology, Shantou University Medical College, Shantou, Guangdong, China
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Hopcraft SE, Pattenden SG, James LI, Frye S, Dittmer DP, Damania B. Chromatin remodeling controls Kaposi's sarcoma-associated herpesvirus reactivation from latency. PLoS Pathog 2018; 14:e1007267. [PMID: 30212584 PMCID: PMC6136816 DOI: 10.1371/journal.ppat.1007267] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 08/07/2018] [Indexed: 01/08/2023] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiologic agent of three human malignancies, the endothelial cell cancer Kaposi's sarcoma, and two B cell cancers, Primary Effusion Lymphoma and multicentric Castleman's disease. KSHV has latent and lytic phases of the viral life cycle, and while both contribute to viral pathogenesis, lytic proteins contribute to KSHV-mediated oncogenesis. Reactivation from latency is driven by the KSHV lytic gene transactivator RTA, and RTA transcription is controlled by epigenetic modifications. To identify host chromatin-modifying proteins that are involved in the latent to lytic transition, we screened a panel of inhibitors that target epigenetic regulatory proteins for their ability to stimulate KSHV reactivation. We found several novel regulators of viral reactivation: an inhibitor of Bmi1, PTC-209, two additional histone deacetylase inhibitors, Romidepsin and Panobinostat, and the bromodomain inhibitor (+)-JQ1. All of these compounds stimulate lytic gene expression, viral genome replication, and release of infectious virions. Treatment with Romidepsin, Panobinostat, and PTC-209 induces histone modifications at the RTA promoter, and results in nucleosome depletion at this locus. Finally, silencing Bmi1 induces KSHV reactivation, indicating that Bmi1, a member of the Polycomb repressive complex 1, is critical for maintaining KSHV latency.
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Affiliation(s)
- Sharon E. Hopcraft
- Lineberger Comprehensive Cancer Center, Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America
| | - Samantha G. Pattenden
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America
| | - Lindsey I. James
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America
| | - Stephen Frye
- Center for Integrative Chemical Biology and Drug Discovery, Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America
| | - Dirk P. Dittmer
- Lineberger Comprehensive Cancer Center, Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America
| | - Blossom Damania
- Lineberger Comprehensive Cancer Center, Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America
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Kumar R, Khandelwal N, Thachamvally R, Tripathi BN, Barua S, Kashyap SK, Maherchandani S, Kumar N. Role of MAPK/MNK1 signaling in virus replication. Virus Res 2018; 253:48-61. [PMID: 29864503 PMCID: PMC7114592 DOI: 10.1016/j.virusres.2018.05.028] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 04/16/2018] [Accepted: 05/31/2018] [Indexed: 12/23/2022]
Abstract
Viruses are known to exploit cellular signaling pathways. MAPK is a major cell signaling pathway activated by diverse group of viruses. MNK1 regulates both cap-dependent and IRES-mediated mRNA translation. This review discuss the role of MAPK, particularly the role of MNK1 in virus replication.
Viruses are obligate intracellular parasites; they heavily depend on the host cell machinery to effectively replicate and produce new progeny virus particles. Following viral infection, diverse cell signaling pathways are initiated by the cells, with the major goal of establishing an antiviral state. However, viruses have been shown to exploit cellular signaling pathways for their own effective replication. Genome-wide siRNA screens have also identified numerous host factors that either support (proviral) or inhibit (antiviral) virus replication. Some of the host factors might be dispensable for the host but may be critical for virus replication; therefore such cellular factors may serve as targets for development of antiviral therapeutics. Mitogen activated protein kinase (MAPK) is a major cell signaling pathway that is known to be activated by diverse group of viruses. MAPK interacting kinase 1 (MNK1) has been shown to regulate both cap-dependent and internal ribosomal entry sites (IRES)-mediated mRNA translation. In this review we have discuss the role of MAPK in virus replication, particularly the role of MNK1 in replication and translation of viral genome.
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Affiliation(s)
- Ram Kumar
- Virology Laboratory, National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, Haryana 125001, India; Department of Veterinary Microbiology and Biotechnology, Rajasthan University of Veterinary and Animal Sciences, Bikaner, Rajasthan 334001, India
| | - Nitin Khandelwal
- Virology Laboratory, National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, Haryana 125001, India
| | - Riyesh Thachamvally
- Virology Laboratory, National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, Haryana 125001, India
| | - Bhupendra Nath Tripathi
- Virology Laboratory, National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, Haryana 125001, India
| | - Sanjay Barua
- Virology Laboratory, National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, Haryana 125001, India
| | - Sudhir Kumar Kashyap
- Department of Veterinary Microbiology and Biotechnology, Rajasthan University of Veterinary and Animal Sciences, Bikaner, Rajasthan 334001, India
| | - Sunil Maherchandani
- Department of Veterinary Microbiology and Biotechnology, Rajasthan University of Veterinary and Animal Sciences, Bikaner, Rajasthan 334001, India
| | - Naveen Kumar
- Virology Laboratory, National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, Haryana 125001, India.
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K15 Protein of Kaposi's Sarcoma Herpesviruses Increases Endothelial Cell Proliferation and Migration through Store-Operated Calcium Entry. Viruses 2018; 10:v10060282. [PMID: 29795033 PMCID: PMC6024707 DOI: 10.3390/v10060282] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 05/06/2018] [Accepted: 05/09/2018] [Indexed: 01/11/2023] Open
Abstract
Kaposi's sarcoma (KS) is a tumor of the vascular endothelium that is caused by Kaposi's sarcoma-associated herpesvirus (KSHV). K15 of KSHV is a specific gene encoding a transmembrane protein. Two highly different forms of K15, the predominant (K15P) and minor (K15M) have been identified in different KSHV strains. In genomic locations and protein topology, two K15 alleles resemble the latent membrane protein (LMP) 1 and LMP2A of Epstein⁻Barr virus. Both K15 proteins have motifs similar to those found in LMP1 and LMP2A. K15 therefore seems to be a hybrid of a distant evolutionary relative of LMP1 and LMP2A. Ca2+ is a second messenger and participates in numerous activities in cells, like proliferation, migration and metastasis. It has been found previously that LMP1 increased Ca2+ influx through store-operated calcium channels and blockade of LMP1 reduced store-operated Ca2+ entry (SOCE). LMP2A has similar activity. So we sought to determine whether K15 had similar activity. We showed that K15P induced Ca2+ influx and enhanced expression of Orail1, which is a vital protein in SOCE, and overexpression of K15P improved cell motility. Mutant K15P did not show these activities in HEK-293T and EA.hy 926 cells. Our results showed that K15P increased cell proliferation and migration though SOCE and established a novel mechanism for the development of KS and KSHV-associated diseases.
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Metabolic reprogramming of Kaposi's sarcoma associated herpes virus infected B-cells in hypoxia. PLoS Pathog 2018; 14:e1007062. [PMID: 29746587 PMCID: PMC5963815 DOI: 10.1371/journal.ppat.1007062] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 05/22/2018] [Accepted: 04/27/2018] [Indexed: 12/26/2022] Open
Abstract
Kaposi’s sarcoma associated herpesvirus (KSHV) infection stabilizes hypoxia inducible factors (HIFs). The interaction between KSHV encoded factors and HIFs plays a critical role in KSHV latency, reactivation and associated disease phenotypes. Besides modulation of large-scale signaling, KSHV infection also reprograms the metabolic activity of infected cells. However, the mechanism and cellular pathways modulated during these changes are poorly understood. We performed comparative RNA sequencing analysis on cells with stabilized hypoxia inducible factor 1 alpha (HIF1α) of KSHV negative or positive background to identify changes in global and metabolic gene expression. Our results show that hypoxia induces glucose dependency of KSHV positive cells with high glucose uptake and high lactate release. We identified the KSHV-encoded vGPCR, as a novel target of HIF1α and one of the main viral antigens of this metabolic reprogramming. Bioinformatics analysis of vGPCR promoter identified 9 distinct hypoxia responsive elements which were activated by HIF1α in-vitro. Expression of vGPCR alone was sufficient for induction of changes in the metabolic phenotype similar to those induced by KSHV under hypoxic conditions. Silencing of HIF1α rescued the hypoxia associated phenotype of KSHV positive cells. Analysis of the host transcriptome identified several common targets of hypoxia as well as KSHV encoded factors and other synergistically activated genes belonging to cellular pathways. These include those involved in carbohydrate, lipid and amino acids metabolism. Further DNA methyltranferases, DNMT3A and DNMT3B were found to be regulated by either KSHV, hypoxia, or both synergistically at the transcript and protein levels. This study showed distinct and common, as well as synergistic effects of HIF1α and KSHV-encoded proteins on metabolic reprogramming of KSHV-infected cells in the hypoxia. Hypoxia inducible factors (HIFs) play a critical role in survival and growth of cancerous cells, in addition to modulating cellular metabolism. Kaposi’s sarcoma associated herpesvirus (KSHV) infection stabilizes HIFs. Several factors encoded by KSHV are known to interact with up or downstream targets of HIFs. However, the process by which KSHV infection leads to stabilized HIF1α and modulation of the cellular metabolism is not understood. Comparative RNA sequencing analysis on cells with stabilized hypoxia inducible factor 1 alpha (HIF1α), of KSHV negative or positive cells led to identification of changes in global and metabolic gene expression. Our results show that hypoxia induces glucose dependency of KSHV positive cells with high glucose uptake and high lactate release. KSHV-encoded vGPCR was identified as a novel target of HIF1α regulation and a major viral antigen involved in metabolic reprogramming. Silencing of HIF1α rescued the hypoxia associated phenotype of KSHV positive cells. Analysis of the host transcriptome identified several common targets of hypoxia and KSHV-encoded factors, as well as other synergistically activated genes belonging to cellular metabolic pathways. This study showed unique, common and the synergistic effects of both HIF1α and KSHV-encoded proteins on metabolic reprogramming of KSHV-infected cells in hypoxia.
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Gelgor A, Gam Ze Letova C, Yegorov Y, Kalt I, Sarid R. Nucleolar stress enhances lytic reactivation of the Kaposi's sarcoma-associated herpesvirus. Oncotarget 2018; 9:13822-13833. [PMID: 29568397 PMCID: PMC5862618 DOI: 10.18632/oncotarget.24497] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 02/01/2018] [Indexed: 02/07/2023] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) is a human tumorigenic virus exhibiting two forms of infection, latent and lytic. Latent infection is abortive and allows the virus to establish lifelong infection, while lytic infection is productive, and is needed for virus dissemination within the host and between hosts. Latent infection may reactivate and switch towards the lytic cycle. This switch is a critical step in the maintenance of long-term infection and for the development of KSHV-related neoplasms. In this study, we examined the effect of nucleolar stress, manifested by failure in ribosome biogenesis or function and often coupled with p53 activation, on lytic reactivation of KSHV. To this end, we induced nucleolar stress by treatment with Actinomycin D, CX-5461 or BMH-21. Treatment with these compounds alone did not induce the lytic cycle. However, enhancement of the lytic cycle by these compounds was evident when combined with expression of the viral protein K-Rta. Further experiments employing combined treatments with Nutlin-3, knock-down of p53 and isogenic p53+/+ and p53-/- cells indicated that the enhancement of lytic reactivation by nucleolar stress does not depend on p53. Thus, our study identifies nucleolar stress as a novel regulator of KSHV infection, which synergizes with K-Rta expression to increase lytic reactivation. This suggests that certain therapeutic interventions, which induce nucleolar stress, may affect the outcome of KSHV infection.
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Affiliation(s)
- Anastasia Gelgor
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar Ilan University, Ramat-Gan, Israel
| | - Chen Gam Ze Letova
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar Ilan University, Ramat-Gan, Israel
| | - Yana Yegorov
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar Ilan University, Ramat-Gan, Israel
| | - Inna Kalt
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar Ilan University, Ramat-Gan, Israel
| | - Ronit Sarid
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar Ilan University, Ramat-Gan, Israel
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Tan B, Liu H, Zhang S, da Silva SR, Zhang L, Meng J, Cui X, Yuan H, Sorel O, Zhang SW, Huang Y, Gao SJ. Viral and cellular N 6-methyladenosine and N 6,2'-O-dimethyladenosine epitranscriptomes in the KSHV life cycle. Nat Microbiol 2018; 3:108-120. [PMID: 29109479 PMCID: PMC6138870 DOI: 10.1038/s41564-017-0056-8] [Citation(s) in RCA: 115] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 10/09/2017] [Indexed: 02/05/2023]
Abstract
N6-methyladenosine (m6A) and N6,2'-O-dimethyladenosine (m6Am) modifications (m6A/m) of messenger RNA mediate diverse cellular functions. Oncogenic Kaposi's sarcoma-associated herpesvirus (KSHV) has latent and lytic replication phases that are essential for the development of KSHV-associated cancers. To date, the role of m6A/m in KSHV replication and tumorigenesis is unclear. Here, we provide mechanistic insights by examining the viral and cellular m6A/m epitranscriptomes during KSHV latent and lytic infection. KSHV transcripts contain abundant m6A/m modifications during latent and lytic replication, and these modifications are highly conserved among different cell types and infection systems. Knockdown of YTHDF2 enhanced lytic replication by impeding KSHV RNA degradation. YTHDF2 binds to viral transcripts and differentially mediates their stability. KSHV latent infection induces 5' untranslated region (UTR) hypomethylation and 3'UTR hypermethylation of the cellular epitranscriptome, regulating oncogenic and epithelial-mesenchymal transition pathways. KSHV lytic replication induces dynamic reprogramming of epitranscriptome, regulating pathways that control lytic replication. These results reveal a critical role of m6A/m modifications in KSHV lifecycle and provide rich resources for future investigations.
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Affiliation(s)
- Brandon Tan
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Hui Liu
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
- School of Information and Electrical Engineering, China University of Mining and Technology, Xuzhou, Jiangsu, China
| | - Songyao Zhang
- Department of Electrical and Computer Engineering, University of Texas at San Antonio, San Antonio, TX, USA
- School of Automation, Northwestern Polytechnic University, Xi'an, Shaanxi, China
| | - Suzane Ramos da Silva
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Lin Zhang
- School of Information and Electrical Engineering, China University of Mining and Technology, Xuzhou, Jiangsu, China
- Department of Electrical and Computer Engineering, University of Texas at San Antonio, San Antonio, TX, USA
| | - Jia Meng
- Department of Biological Sciences, Xi'an Jiaotong-Liverpool University, Suzhou, Jiangsu, China
| | - Xiaodong Cui
- Department of Electrical and Computer Engineering, University of Texas at San Antonio, San Antonio, TX, USA
| | - Hongfeng Yuan
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Océane Sorel
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Shao-Wu Zhang
- School of Automation, Northwestern Polytechnic University, Xi'an, Shaanxi, China
| | - Yufei Huang
- Department of Electrical and Computer Engineering, University of Texas at San Antonio, San Antonio, TX, USA.
| | - Shou-Jiang Gao
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
- Laboratory of Human Virology and Oncology, Shantou University Medical College, Shantou, Guangdong, China.
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Watanabe T, Sugimoto A, Hosokawa K, Fujimuro M. Signal Transduction Pathways Associated with KSHV-Related Tumors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1045:321-355. [PMID: 29896674 DOI: 10.1007/978-981-10-7230-7_15] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Signal transduction pathways play a key role in the regulation of cell growth, cell differentiation, cell survival, apoptosis, and immune responses. Bacterial and viral pathogens utilize the cell signal pathways by encoding their own proteins or noncoding RNAs to serve their survival and replication in infected cells. Kaposi's sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus 8 (HHV-8), is classified as a rhadinovirus in the γ-herpesvirus subfamily and was the eighth human herpesvirus to be discovered from Kaposi's sarcoma specimens. KSHV is closely associated with an endothelial cell malignancy, Kaposi's sarcoma, and B-cell malignancies, primary effusion lymphoma, and multicentric Castleman's disease. Recent studies have revealed that KSHV manipulates the cellular signaling pathways to achieve persistent infection, viral replication, cell proliferation, anti-apoptosis, and evasion of immune surveillance in infected cells. This chapter summarizes recent developments in our understanding of the molecular mechanisms used by KSHV to interact with the cell signaling machinery.
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Affiliation(s)
- Tadashi Watanabe
- Department of Cell Biology, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Atsuko Sugimoto
- Department of Cell Biology, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Kohei Hosokawa
- Department of Cell Biology, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Masahiro Fujimuro
- Department of Cell Biology, Kyoto Pharmaceutical University, Kyoto, Japan.
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Antiviral activity of ginsenoside Rg3 isomers against gammaherpesvirus through inhibition of p38- and JNK-associated pathways. J Funct Foods 2018. [DOI: 10.1016/j.jff.2017.11.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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Tsai CY, Chen CY, Chiou YH, Shyu HW, Lin KH, Chou MC, Huang MH, Wang YF. Epigallocatechin-3-Gallate Suppresses Human Herpesvirus 8 Replication and Induces ROS Leading to Apoptosis and Autophagy in Primary Effusion Lymphoma Cells. Int J Mol Sci 2017; 19:ijms19010016. [PMID: 29267216 PMCID: PMC5795967 DOI: 10.3390/ijms19010016] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Revised: 12/15/2017] [Accepted: 12/18/2017] [Indexed: 12/02/2022] Open
Abstract
Epigallocatechin-3-gallate (EGCG), the major constituent of green tea, has been shown to induce cell death in cancer cells. Primary effusion lymphoma (PEL) is an aggressive neoplasm caused by human herpesvirus 8 (HHV8). In this study, we examined the role of EGCG on PEL cells in cell death and HHV8 replication. We performed trypan blue exclusion assay to assess the cell viability of PEL cells, flow cytometry analysis to examine the cell cycle distribution and reactive oxygen species (ROS) generation, caspase-3 activity to assay apoptosis, acridine orange staining to determine autophagy, and immunoblotting to detect the protein levels involved in apoptosis and autophagy as well as mitogen activated protein kinases (MAPKs) activation upon EGCG treatment. The expression of the HHV8 lytic gene was determined by luciferase reporter assay and reverse transcription-PCR, and viral progeny production was determined by PCR. Results revealed that EGCG induced cell death and ROS generation in PEL cells in a dose-dependent manner. N-acetylcysteine (NAC) inhibited the EGCG-induced ROS and rescued the cell from EGCG-induced cell death. Even though EGCG induced ROS generation in PEL cells, it reduced the production of progeny virus from PEL cells without causing HHV8 reactivation. These results suggest that EGCG may represent a novel strategy for the treatment of HHV8 infection and HHV8-associated lymphomas.
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Affiliation(s)
- Ching-Yi Tsai
- Department of Medical Laboratory Science and Biotechnology, Fooyin-University, Kaohsiung 83102, Taiwan.
| | - Chang-Yu Chen
- Department of Medical Laboratory Science and Biotechnology, Fooyin-University, Kaohsiung 83102, Taiwan.
| | - Yee-Hsuan Chiou
- Department of Pediatrics, Kaohsiung Veterans General Hospital, Kaohsiung 83102, Taiwan.
| | - Huey-Wen Shyu
- Department of Medical Laboratory Science and Biotechnology, Fooyin-University, Kaohsiung 83102, Taiwan.
| | - Kuan-Hua Lin
- Department of Medical Laboratory Science and Biotechnology, Fooyin-University, Kaohsiung 83102, Taiwan.
| | - Miao-Chen Chou
- Department of Medical Laboratory Science and Biotechnology, Fooyin-University, Kaohsiung 83102, Taiwan.
| | - Mei-Han Huang
- Department of Medical Laboratory Science and Biotechnology, Fooyin-University, Kaohsiung 83102, Taiwan.
| | - Yi-Fen Wang
- Department of Medical Laboratory Science and Biotechnology, Fooyin-University, Kaohsiung 83102, Taiwan.
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Full-Length Isoforms of Kaposi's Sarcoma-Associated Herpesvirus Latency-Associated Nuclear Antigen Accumulate in the Cytoplasm of Cells Undergoing the Lytic Cycle of Replication. J Virol 2017; 91:JVI.01532-17. [PMID: 28978712 DOI: 10.1128/jvi.01532-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 09/29/2017] [Indexed: 01/09/2023] Open
Abstract
The latency-associated nuclear antigen (LANA) of the Kaposi's sarcoma-associated herpesvirus (KSHV) performs a variety of functions to establish and maintain KSHV latency. During latency, LANA localizes to discrete punctate spots in the nucleus, where it tethers viral episomes to cellular chromatin and interacts with nuclear components to regulate cellular and viral gene expression. Using highly sensitive tyramide signal amplification, we determined that LANA localizes to the cytoplasm in different cell types undergoing the lytic cycle of replication after de novo primary infection and after spontaneous, tetradecanoyl phorbol acetate-, or open reading frame 50 (ORF50)/replication transactivator (RTA)-induced activation. We confirmed the presence of cytoplasmic LANA in a subset of cells in lytically active multicentric Castleman disease lesions. The induction of cellular migration by scratch-wounding confluent cell cultures, culturing under subconfluent conditions, or induction of cell differentiation in primary cultures upregulated the number of cells permissive for primary lytic KSHV infection. The induction of lytic replication was characterized by high-level expression of cytoplasmic LANA and nuclear ORF59, a marker of lytic replication. Subcellular fractionation studies revealed the presence of multiple isoforms of LANA in the cytoplasm of ORF50/RTA-activated Vero cells undergoing primary infection. Mass spectrometry analysis demonstrated that cytoplasmic LANA isoforms were full length, containing the N-terminal nuclear localization signal. These results suggest that trafficking of LANA to different subcellular locations is a regulated phenomenon, which allows LANA to interact with cellular components in different compartments during both the latent and the replicative stages of the KSHV life cycle.IMPORTANCE Kaposi's sarcoma-associated herpesvirus (KSHV) causes AIDS-related malignancies, including lymphomas and Kaposi's sarcoma. KSHV establishes lifelong infections using its latency-associated nuclear antigen (LANA). During latency, LANA localizes to the nucleus, where it connects viral and cellular DNA complexes and regulates gene expression, allowing the virus to maintain long-term infections. Our research shows that intact LANA traffics to the cytoplasm of cells undergoing permissive lytic infections and latently infected cells in which the virus is induced to replicate. This suggests that LANA plays important roles in the cytoplasm and nuclear compartments of the cell during different stages of the KSHV life cycle. Determining cytoplasmic function and mechanism for regulation of the nuclear localization of LANA will enhance our understanding of the biology of this virus, leading to therapeutic approaches to eliminate infection and block its pathological effects.
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1, 25(OH)2 D3 Induces Reactivation and Death of Kaposi's Sarcoma-Associated Herpesvirus of Primary Effusion Lymphoma cells. Sci Rep 2017; 7:12438. [PMID: 28963501 PMCID: PMC5622028 DOI: 10.1038/s41598-017-12676-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 09/05/2017] [Indexed: 12/31/2022] Open
Abstract
Kaposi's sarcoma associated herpesvirus (KSHV) a gammaherpesvirus establishes perennial latency in the host with periodic reactivation. Occasionally change in the physiological condition like hypoxia, host cell differentiation can trigger the lytic switch and reactivation of the virus. The biologically active form of 1, 25(OH)2 D3 plays a critical role in the regulation of various physiological processes (e.g. regulation of mineral homeostasis and control of bone metabolism). Apart from its role in host physiology, 1, 25(OH)2 D3 has been implicated as a potential agent for the prevention and/or treatment of many a tumors. Here we show that 1, 25(OH)2 D3 induces both death of Kaposi sarcoma associated herpesvirus infected PEL cells and KSHV replication. 1, 25(OH)2 D3 mediated inhibition of proliferation was associated with apoptosis of the PEL cells, and virus reactivation. In addition, p38 signalling is required for KSHV reactivation. Furthermore, treatment of PEL cells with p38 inhibitor abrogated the expression of ORF57, thus blocking lytic switch. Furthermore, silencing of VDR resulted in reduced ORF57 expression compared to the control cells, signifying the potential role of 1, 25(OH)2 D3 in KSHV reactivation. Thus, our studies have revealed a novel role of 1, 25(OH)2 D3 in the regulation of KSHV reactivation and PEL cell death.
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Abere B, Mamo TM, Hartmann S, Samarina N, Hage E, Rückert J, Hotop SK, Büsche G, Schulz TF. The Kaposi's sarcoma-associated herpesvirus (KSHV) non-structural membrane protein K15 is required for viral lytic replication and may represent a therapeutic target. PLoS Pathog 2017; 13:e1006639. [PMID: 28938025 PMCID: PMC5627962 DOI: 10.1371/journal.ppat.1006639] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 10/04/2017] [Accepted: 09/09/2017] [Indexed: 12/18/2022] Open
Abstract
Kaposi’s sarcoma-associated herpesvirus (KSHV) is the infectious cause of the highly vascularized tumor Kaposi’s sarcoma (KS), which is characterized by proliferating spindle cells of endothelial origin, extensive neo-angiogenesis and inflammatory infiltrates. The KSHV K15 protein contributes to the angiogenic and invasive properties of KSHV-infected endothelial cells. Here, we asked whether K15 could also play a role in KSHV lytic replication. Deletion of the K15 gene from the viral genome or its depletion by siRNA lead to reduced virus reactivation, as evidenced by the decreased expression levels of KSHV lytic proteins RTA, K-bZIP, ORF 45 and K8.1 as well as reduced release of infectious virus. Similar results were found for a K1 deletion virus. Deleting either K15 or K1 from the viral genome also compromised the ability of KSHV to activate PLCγ1, Erk1/2 and Akt1. In infected primary lymphatic endothelial (LEC-rKSHV) cells, which have previously been shown to spontaneously display a viral lytic transcription pattern, transfection of siRNA against K15, but not K1, abolished viral lytic replication as well as KSHV-induced spindle cell formation. Using a newly generated monoclonal antibody to K15, we found an abundant K15 protein expression in KS tumor biopsies obtained from HIV positive patients, emphasizing the physiological relevance of our findings. Finally, we used a dominant negative inhibitor of the K15-PLCγ1 interaction to establish proof of principle that pharmacological intervention with K15-dependent pathways may represent a novel approach to block KSHV reactivation and thereby its pathogenesis. Both the latent and lytic replication phases of the KSHV life cycle are thought to contribute to its persistence and pathogenesis. The non-structural signaling membrane protein K15 is involved in the angiogenic and invasive properties of KSHV-infected endothelial cells. Here we show that the K15 protein is required for virus replication, early viral gene expression and virus production through its activation of the cellular signaling pathways PLCγ1 and Erk 1/2. K15 is abundantly expressed in KSHV-infected lymphatic endothelial cells (LECs) and contributes to KSHV-induced endothelial spindle cell formation. The abundant K15 protein expression observed in LECs is also observed in KS tumors. We also show that it may be possible to target K15 in order to intervene therapeutically with KSHV lytic replication and pathogenesis.
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Affiliation(s)
- Bizunesh Abere
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Centre for Infection Research, Hannover–Braunschweig Site, Germany
| | - Tamrat M. Mamo
- Institute of Molecular Biology, Hannover Medical School, Hannover, Germany
| | - Silke Hartmann
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Centre for Infection Research, Hannover–Braunschweig Site, Germany
| | - Naira Samarina
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Centre for Infection Research, Hannover–Braunschweig Site, Germany
| | - Elias Hage
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Centre for Infection Research, Hannover–Braunschweig Site, Germany
| | - Jessica Rückert
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Centre for Infection Research, Hannover–Braunschweig Site, Germany
| | - Sven-Kevin Hotop
- German Centre for Infection Research, Hannover–Braunschweig Site, Germany
- Department of Chemical Biology, Helmholtz Center for Infection Research, Braunschweig, Germany
| | - Guntram Büsche
- Institute of Pathology, Hannover Medical School, Hannover, Germany
| | - Thomas F. Schulz
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Centre for Infection Research, Hannover–Braunschweig Site, Germany
- * E-mail:
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Sarkar R, Verma SC. Egr-1 regulates RTA transcription through a cooperative involvement of transcriptional regulators. Oncotarget 2017; 8:91425-91444. [PMID: 29207655 PMCID: PMC5710935 DOI: 10.18632/oncotarget.20648] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 07/26/2017] [Indexed: 11/25/2022] Open
Abstract
Kaposi's sarcoma associated herpesvirus (KSHV) regulates the host cellular environment to establish life-long persistent infection by manipulating cellular signaling pathways, with approximately 1- 5% of cells undergoing lytic reactivation during the course of infection. Egr-1 (Early Growth Response Factor-1) is one such cellular transcription factor, which gets phosphorylated during the lytic phase of viral life cycle to perpetrate its function. This study demonstrates the mechanism of how Egr-1 mediates transcription of the immediate early gene, RTA (Replication and transcription activator), which is the lytic switch gene of KSHV. Egr-1 depleted KSHV infected cells exhibited reduced expression of RTA. Also, an increase in Egr-1 phosphorylation led to a higher virion production, which was suppressed in the presence of p38 and Raf inhibitors. Reporter assays showed that coexpression of Egr-1 and CBP (CREB-binding protein) enhances RTA promoter activity as compared to the expression of either Egr-1 or CBP alone. Binding of Egr-1 and CBP at RTA promoter was analyzed by chromatin immunoprecipitation assay (ChIP), which showed an enhanced accumulation during viral reactivation. Mutation in Egr-1 binding site of the RTA promoter eliminated Egr-1 response on promoter activation. Furthermore, de novo infection of THP-1 (monocytic) and HUVECs (endothelial) cells showed an upregulation of Egr-1 phosphorylation, whereas depletion of Egr-1 reduced the mRNA levels of RTA during primary infection. Together, these results demonstrate a cooperative role of Egr-1 and CBP in mediating RTA transcription, which significantly improves our understanding of the involvement of cellular factors controlling RTA transcription in KSHV pathogenesis.
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Affiliation(s)
- Roni Sarkar
- Department of Microbiology and Immunology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Subhash C Verma
- Department of Microbiology and Immunology, University of Nevada, Reno School of Medicine, Reno, NV, USA
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Wong JP, Damania B. Modulation of oncogenic signaling networks by Kaposi's sarcoma-associated herpesvirus. Biol Chem 2017; 398:911-918. [PMID: 28284028 DOI: 10.1515/hsz-2017-0101] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Accepted: 03/08/2017] [Indexed: 01/07/2023]
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiological agent of three human malignancies: Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease. To persist and replicate within host cells, KSHV encodes proteins that modulate different signaling pathways. Manipulation of cell survival and proliferative networks by KSHV can promote the development of KSHV-associated malignancies. In this review, we discuss recent updates on KSHV pathogenesis and the viral life cycle. We focus on proteins encoded by KSHV that modulate the phosphatidylinositol-4,5-bisphosphate 3 kinase and extracellular signal-regulated kinases 1/2 pathways to create an environment favorable for viral replication and the development of KSHV malignancies.
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Arnold N, Messaoudi I. Simian varicella virus causes robust transcriptional changes in T cells that support viral replication. Virus Res 2017; 238:226-235. [PMID: 28698046 PMCID: PMC7114558 DOI: 10.1016/j.virusres.2017.07.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Revised: 05/24/2017] [Accepted: 07/04/2017] [Indexed: 12/13/2022]
Abstract
T cells play a major role in varicella viruses dissemination to ganglia and skin. SVV infection of T cells increases the expression of cell cycle genes. SVV infection downregulates genes important for antigen presentation in T cells. SVV T cell infection disrupts expression of genes vital for metabolism and immunity.
Varicella zoster virus (VZV) causes varicella (chickenpox) during acute infection. Several studies have shown that T cells are early and preferential targets of VZV infection that play a critical role in disseminating VZV in to the skin and ganglia. However, the transcriptional changes that occur in VZV-infected T cells remain unclear due to limited access to clinical samples and robust translational animal models. In this study, we used a nonhuman primate model of VZV infection where rhesus macaques are infected with the closely related Simian Varicella Virus (SVV) to provide novel insights into VZV-T cell interactions. RNA sequencing of bronchial alveolar lavage-resident T cells isolated from infected rhesus macaques show that SVV infection alters expression of genes important for regulation of gene expression, cell cycle progression, metabolism, and antiviral immunity. These data provide insight into cellular processes that may support viral replication, facilitate SVV dissemination, and evade host defense.
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Affiliation(s)
- Nicole Arnold
- Graduate Program in Microbiology, University of California, Riverside, CA, USA
| | - Ilhem Messaoudi
- Department of Molecular Biology and Biochemistry, University of California-Irvine, Irvine, CA, 92697, USA.
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Aneja KK, Yuan Y. Reactivation and Lytic Replication of Kaposi's Sarcoma-Associated Herpesvirus: An Update. Front Microbiol 2017; 8:613. [PMID: 28473805 PMCID: PMC5397509 DOI: 10.3389/fmicb.2017.00613] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 03/27/2017] [Indexed: 12/30/2022] Open
Abstract
The life cycle of Kaposi’s sarcoma-associated herpesvirus (KSHV) consists of two phases, latent and lytic. The virus establishes latency as a strategy for avoiding host immune surveillance and fusing symbiotically with the host for lifetime persistent infection. However, latency can be disrupted and KSHV is reactivated for entry into the lytic replication. Viral lytic replication is crucial for efficient dissemination from its long-term reservoir to the sites of disease and for the spread of the virus to new hosts. The balance of these two phases in the KSHV life cycle is important for both the virus and the host and control of the switch between these two phases is extremely complex. Various environmental factors such as oxidative stress, hypoxia, and certain chemicals have been shown to switch KSHV from latency to lytic reactivation. Immunosuppression, unbalanced inflammatory cytokines, and other viral co-infections also lead to the reactivation of KSHV. This review article summarizes the current understanding of the initiation and regulation of KSHV reactivation and the mechanisms underlying the process of viral lytic replication. In particular, the central role of an immediate-early gene product RTA in KSHV reactivation has been extensively investigated. These studies revealed multiple layers of regulation in activation of RTA as well as the multifunctional roles of RTA in the lytic replication cascade. Epigenetic regulation is known as a critical layer of control for the switch of KSHV between latency and lytic replication. The viral non-coding RNA, PAN, was demonstrated to play a central role in the epigenetic regulation by serving as a guide RNA that brought chromatin remodeling enzymes to the promoters of RTA and other lytic genes. In addition, a novel dimension of regulation by microPeptides emerged and has been shown to regulate RTA expression at the protein level. Overall, extensive investigation of KSHV reactivation and lytic replication has revealed a sophisticated regulation network that controls the important events in KSHV life cycle.
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Affiliation(s)
- Kawalpreet K Aneja
- Department of Microbiology, University of Pennsylvania School of Dental Medicine, PhiladelphiaPA, USA
| | - Yan Yuan
- Department of Microbiology, University of Pennsylvania School of Dental Medicine, PhiladelphiaPA, USA
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Zhong C, Xu M, Wang Y, Xu J, Yuan Y. An APE1 inhibitor reveals critical roles of the redox function of APE1 in KSHV replication and pathogenic phenotypes. PLoS Pathog 2017; 13:e1006289. [PMID: 28380040 PMCID: PMC5381946 DOI: 10.1371/journal.ppat.1006289] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2016] [Accepted: 03/11/2017] [Indexed: 01/04/2023] Open
Abstract
APE1 is a multifunctional protein with a DNA base excision repair function in its C-terminal domain and a redox activity in its N-terminal domain. The redox function of APE1 converts certain transcription factors from inactive oxidized to active reduced forms. Given that among the APE1-regulated transcription factors many are critical for KSHV replication and pathogenesis, we investigated whether inhibition of APE1 redox function blocks KSHV replication and Kaposi’s sarcoma (KS) phenotypes. With an shRNA-mediated silencing approach and a known APE-1 redox inhibitor, we demonstrated that APE1 redox function is indeed required for KSHV replication as well as KSHV-induced angiogenesis, validating APE1 as a therapeutic target for KSHV-associated diseases. A ligand-based virtual screening yielded a small molecular compound, C10, which is proven to bind to APE1. C10 exhibits low cytotoxicity but efficiently inhibits KSHV lytic replication (EC50 of 0.16 μM and selective index of 165) and KSHV-mediated pathogenic phenotypes including cytokine production, angiogenesis and cell invasion, demonstrating its potential to become an effective drug for treatment of KS. As a major AIDS-associated malignancy, Kaposi’s sarcoma (KS) is caused by Kaposi’s sarcoma-associated herpesvirus (KSHV). Currently there is no definitive cure for KS. In this study, we identified a cellular protein, namely APE1, as an effective therapeutic target for blocking KSHV replication and inhibiting the development of KS phenotypes. We showed that the redox function of APE1 is absolutely required for KSHV replication, virally induced cytokine secretion and angiogenesis. Blockade of APE1 expression or inhibition of APE1 redox activity led to inhibition of KSHV replication and reduction of cytokine release and angiogenesis. Furthermore, we identified a novel small molecular compound, C10, which exhibited specific inhibitory activity on APE1 redox function and was demonstrated to efficiently inhibit KSHV replication and paracrine-mediated KS phenotypes such as angiogenesis and cell invasion. As a potent inhibitor of APE1 redox, C10 not only has value in development of a novel therapeutics for KS, but also may be used in therapies for other human diseases such as leukemia, pancreatic cancer and macular degeneration.
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Affiliation(s)
- Canrong Zhong
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China
- Key Laboratory of Tropical Disease Control, Ministry of Education, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Mengyang Xu
- Research Center for Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Yan Wang
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China
- Guanghua School of Stomatology, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Jun Xu
- Research Center for Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou, Guangdong, China
- * E-mail: (YY); (JX)
| | - Yan Yuan
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, China
- Key Laboratory of Tropical Disease Control, Ministry of Education, Sun Yat-Sen University, Guangzhou, Guangdong, China
- Department of Microbiology, University of Pennsylvania School of Dental Medicine, Philadelphia, Pennsylvania, United States of America
- * E-mail: (YY); (JX)
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Balistreri G, Viiliäinen J, Turunen M, Diaz R, Lyly L, Pekkonen P, Rantala J, Ojala K, Sarek G, Teesalu M, Denisova O, Peltonen K, Julkunen I, Varjosalo M, Kainov D, Kallioniemi O, Laiho M, Taipale J, Hautaniemi S, Ojala PM. Oncogenic Herpesvirus Utilizes Stress-Induced Cell Cycle Checkpoints for Efficient Lytic Replication. PLoS Pathog 2016; 12:e1005424. [PMID: 26891221 PMCID: PMC4758658 DOI: 10.1371/journal.ppat.1005424] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2015] [Accepted: 01/07/2016] [Indexed: 12/31/2022] Open
Abstract
Kaposi’s sarcoma herpesvirus (KSHV) causes Kaposi’s sarcoma and certain lymphoproliferative malignancies. Latent infection is established in the majority of tumor cells, whereas lytic replication is reactivated in a small fraction of cells, which is important for both virus spread and disease progression. A siRNA screen for novel regulators of KSHV reactivation identified the E3 ubiquitin ligase MDM2 as a negative regulator of viral reactivation. Depletion of MDM2, a repressor of p53, favored efficient activation of the viral lytic transcription program and viral reactivation. During lytic replication cells activated a p53 response, accumulated DNA damage and arrested at G2-phase. Depletion of p21, a p53 target gene, restored cell cycle progression and thereby impaired the virus reactivation cascade delaying the onset of virus replication induced cytopathic effect. Herpesviruses are known to reactivate in response to different kinds of stress, and our study now highlights the molecular events in the stressed host cell that KSHV has evolved to utilize to ensure efficient viral lytic replication. Herpesviruses are known to wake up and reactivate in response to different kinds of stress. Our study now highlights the key molecular host cell events that KSHV has evolved to utilize for efficient viral lytic replication: the activation of p53 and upregulation of p21, which slows down the cell cycle, but promotes viral replication and transcription of viral lytic genes. Mutations in TP53 gene are rarely found in KSHV-associated malignancies. Therefore, our work now provides a mechanistic explanation as to why the virus has evolved to retain p53.
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Affiliation(s)
- Giuseppe Balistreri
- Translational Cancer Research Program, Research Programs Unit, University of Helsinki, Helsinki, Finland
| | - Johanna Viiliäinen
- Translational Cancer Research Program, Research Programs Unit, University of Helsinki, Helsinki, Finland
| | - Mikko Turunen
- Genome-Scale Biology Program, Research Programs Unit and Department of Pathology, Haartman Institute, University of Helsinki, Helsinki, Finland
| | - Raquel Diaz
- Translational Cancer Research Program, Research Programs Unit, University of Helsinki, Helsinki, Finland
| | - Lauri Lyly
- Genome-Scale Biology Program, Research Programs Unit, University of Helsinki, Biomedicum Helsinki, Helsinki, Finland
| | - Pirita Pekkonen
- Translational Cancer Research Program, Research Programs Unit, University of Helsinki, Helsinki, Finland
| | | | - Krista Ojala
- Translational Cancer Research Program, Research Programs Unit, University of Helsinki, Helsinki, Finland
| | - Grzegorz Sarek
- Translational Cancer Research Program, Research Programs Unit, University of Helsinki, Helsinki, Finland
| | - Mari Teesalu
- Translational Cancer Research Program, Research Programs Unit, University of Helsinki, Helsinki, Finland
| | - Oxana Denisova
- Institute for Molecular Medicine (FIMM), University of Helsinki, Biomedicum Helsinki, Helsinki, Finland
| | - Karita Peltonen
- Centre for Drug Discovery, University of Helsinki, Helsinki, Finland
| | - Ilkka Julkunen
- Department of Virology, University of Turku and National Institute for Health and Welfare, Turku, Finland
| | - Markku Varjosalo
- Translational Cancer Research Program, Research Programs Unit, University of Helsinki, Helsinki, Finland
| | - Denis Kainov
- Institute for Molecular Medicine (FIMM), University of Helsinki, Biomedicum Helsinki, Helsinki, Finland
| | - Olli Kallioniemi
- Institute for Molecular Medicine (FIMM), University of Helsinki, Biomedicum Helsinki, Helsinki, Finland
| | - Marikki Laiho
- Centre for Drug Discovery, University of Helsinki, Helsinki, Finland
- Department of Radiation Oncology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Jussi Taipale
- Genome-Scale Biology Program, Research Programs Unit and Department of Pathology, Haartman Institute, University of Helsinki, Helsinki, Finland
| | - Sampsa Hautaniemi
- Genome-Scale Biology Program, Research Programs Unit, University of Helsinki, Biomedicum Helsinki, Helsinki, Finland
| | - Päivi M. Ojala
- Translational Cancer Research Program, Research Programs Unit, University of Helsinki, Helsinki, Finland
- Foundation for the Finnish Cancer Institute, Helsinki, Finland
- Section of Virology, Division of Infectious Diseases, Department of Medicine, Imperial College London, London, United Kingdom
- * E-mail:
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Purushothaman P, Dabral P, Gupta N, Sarkar R, Verma SC. KSHV Genome Replication and Maintenance. Front Microbiol 2016; 7:54. [PMID: 26870016 PMCID: PMC4740845 DOI: 10.3389/fmicb.2016.00054] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 01/12/2016] [Indexed: 12/04/2022] Open
Abstract
Kaposi's sarcoma associated herpesvirus (KSHV) or human herpesvirus 8 (HHV8) is a major etiological agent for multiple severe malignancies in immune-compromised patients. KSHV establishes lifetime persistence in the infected individuals and displays two distinct life cycles, generally a prolonged passive latent, and a short productive or lytic cycle. During latent phase, the viral episome is tethered to the host chromosome and replicates once during every cell division. Latency-associated nuclear antigen (LANA) is a predominant multifunctional nuclear protein expressed during latency, which plays a central role in episome tethering, replication and perpetual segregation of the episomes during cell division. LANA binds cooperatively to LANA binding sites (LBS) within the terminal repeat (TR) region of the viral episome as well as to the cellular nucleosomal proteins to tether viral episome to the host chromosome. LANA has been shown to modulate multiple cellular signaling pathways and recruits various cellular proteins such as chromatin modifying enzymes, replication factors, transcription factors, and cellular mitotic framework to maintain a successful latent infection. Although, many other regions within the KSHV genome can initiate replication, KSHV TR is important for latent DNA replication and possible segregation of the replicated episomes. Binding of LANA to LBS favors the recruitment of various replication factors to initiate LANA dependent DNA replication. In this review, we discuss the molecular mechanisms relevant to KSHV genome replication, segregation, and maintenance of latency.
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Affiliation(s)
- Pravinkumar Purushothaman
- Department of Microbiology and Immunology, School of Medicine, University of Nevada, Reno Reno, NV, USA
| | - Prerna Dabral
- Department of Microbiology and Immunology, School of Medicine, University of Nevada, Reno Reno, NV, USA
| | - Namrata Gupta
- Department of Microbiology and Immunology, School of Medicine, University of Nevada, Reno Reno, NV, USA
| | - Roni Sarkar
- Department of Microbiology and Immunology, School of Medicine, University of Nevada, Reno Reno, NV, USA
| | - Subhash C Verma
- Department of Microbiology and Immunology, School of Medicine, University of Nevada, Reno Reno, NV, USA
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Tan X, Gao Y, Nan Y, Zhang J, Di C, Wang X, Lian F, Cao Y, Hu Y, Xu L, Ma H, Hong Y, Liu T, Wu Y, Xu X, Yan Y, Yang L. Cellular MicroRNA Let-7a Suppresses KSHV Replication through Targeting MAP4K4 Signaling Pathways. PLoS One 2015. [PMID: 26197270 PMCID: PMC4511191 DOI: 10.1371/journal.pone.0132148] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Background Kaposi’s sarcoma (KS)-associated herpesvirus (KSHV) is the etiologic agent of KS, the most common AIDS-related malignancy. The majority of KS tumor cells harbor latent KSHV virus but only a small percentage undergoes spontaneous lytic replication. Viral reactivation from latency is crucial for the pathogenesis and development of KS, but the cellular mechanisms underlying the switch between viral latency and replication are not well understood. Methods The level of let-7 miRNAs and MAP4K4 in KSHV infected 293T cells were quantified by real-time PCRs. Let-7 expression was silenced by the miRNA sponge technique. In let-7a transfected 293T cells, the expression of MAP4K4 was measured by real-time PCR and western blot. Luciferease expression was employed to examine the effect of let-7a on the 3’-untranslated region (UTR) of the MAP4K4 gene in 293T cells. Real-time PCR was used to quantify the KSHV copy numbers in BC-3 cells in which the expression of let-7a and/or MAP4K4 were altered. Finally, ERK, JNK and p38 protein production and their phosphorylation status were detected by western blots in let-7a or MAP4K4 transfected BCBL-1 cells. Results The expression of microRNA let-7 was dramatically decreased in KSHV infected 293T cells, but that of MAP4K4 was increased significantly. Let-7a is physically associated with and targets the MAP4K4 3’UTR, and inhibits MAP4K4 expression at both mRNA and protein levels. MAP4K4 stimulates KSHV reactivation from latency, whereas let-7a inhibits the function of MAP4K4 by reversing the function of MAP4K4 on JNK, phospho-JNK and phospho-ERK1/2 levels. Conclusion Our results establish that let-7a specifically suppresses MAP4K4 expression, and further inhibits KSHV reactivation by interfering with the function of MAP4K4 on the MAPK pathway, highlighting let-7a as a potential treatment for KS.
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Affiliation(s)
- Xiaohua Tan
- School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang, China
| | - Yuan Gao
- School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang, China
| | - Yulong Nan
- School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang, China
| | - Jinxia Zhang
- School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang, China
| | - Chunhong Di
- School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang, China
| | - Xiaobo Wang
- School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang, China
| | - Fuzhi Lian
- School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang, China
| | - Yifei Cao
- School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang, China
| | - Yu Hu
- School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang, China
| | - Liangwen Xu
- School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang, China
| | - Haiyan Ma
- School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang, China
| | - Yu Hong
- School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang, China
| | - Tingjie Liu
- School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang, China
| | - Yinyin Wu
- School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang, China
| | - Xianrong Xu
- School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang, China
| | - Yutao Yan
- School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang, China
| | - Lei Yang
- School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang, China
- * E-mail:
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50
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Screening of the Human Kinome Identifies MSK1/2-CREB1 as an Essential Pathway Mediating Kaposi's Sarcoma-Associated Herpesvirus Lytic Replication during Primary Infection. J Virol 2015; 89:9262-80. [PMID: 26109721 DOI: 10.1128/jvi.01098-15] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 06/21/2015] [Indexed: 01/10/2023] Open
Abstract
UNLABELLED Viruses often hijack cellular pathways to facilitate infection and replication. Kaposi's sarcoma-associated herpesvirus (KSHV) is an oncogenic gammaherpesvirus etiologically associated with Kaposi's sarcoma, a vascular tumor of endothelial cells. Despite intensive studies, cellular pathways mediating KSHV infection and replication are still not well defined. Using an antibody array approach, we examined cellular proteins phosphorylated during primary KSHV infection of primary human umbilical vein endothelial cells. Enrichment analysis identified integrin/mitogen-activated protein kinase (integrin/MAPK), insulin/epidermal growth factor receptor (insulin/EGFR), and JAK/STAT as the activated networks during primary KSHV infection. The transcriptional factor CREB1 (cyclic AMP [cAMP]-responsive element-binding protein 1) had the strongest increase in phosphorylation. While knockdown of CREB1 had no effect on KSHV entry and trafficking, it drastically reduced the expression of lytic transcripts and proteins and the production of infectious virions. Chemical activation of CREB1 significantly enhanced viral lytic replication. In contrast, CREB1 neither influenced the expression of the latent gene LANA nor affected KSHV infectivity. Mechanistically, CREB1 was not activated through the classic cAMP/protein kinase A (cAMP/PKA) pathway or via the AKT, MK2, and RSK pathways. Rather, CREB1 was activated by the mitogen- and stress-activated protein kinases 1 and 2 (MSK1/2). Consequently, chemical inhibition or knockdown of MSKs significantly inhibited the KSHV lytic replication program; however, it had a minimal effect on LANA expression and KSHV infectivity. Together, these results identify the MSK1/2-CREB1 proteins as novel essential effectors of KSHV lytic replication during primary infection. The differential effect of the MSK1/2-CREB1 pathway on the expression of viral latent and lytic genes might control the robustness of viral lytic replication, and therefore the KSHV replication program, during primary infection. IMPORTANCE Kaposi's sarcoma-associated herpesvirus (KSHV) is a human tumor virus associated with several cancers. Through genome-wide kinase screening, we found that KSHV activates the MSK1/2-CREB1 pathway during primary infection and that it depends on this pathway for viral lytic replication. Inhibition of this pathway blocks KSHV lytic replication. These results illustrate a mechanism by which KSHV hijacks a cellular pathway for its replication, and they identify a potential therapeutic target.
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