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PLX8394, a RAF inhibitor, inhibits enterovirus 71 replication by blocking RAF/MEK/ERK signaling. Virol Sin 2023; 38:276-284. [PMID: 36669700 PMCID: PMC10176437 DOI: 10.1016/j.virs.2023.01.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 01/13/2023] [Indexed: 01/19/2023] Open
Abstract
Enterovirus 71 (EV71) poses a serious threat to human health, with scattered outbreaks worldwide. There are several vaccines against a few EV71 strains but no efficient drug for the treatment of EV71 infection. Therefore, it is urgent and of significance to develop anti-EV71 drugs. Here, we found that PLX8394, a RAF inhibitor, possesses high antiviral activity against EV71 in vitro, being superior to the traditional clinical drug ribavirin. Moreover, PLX8394 exhibits broad-spectrum antiviral activity against enteroviruses. Notably, in a suckling mouse model, PLX8394 provided a 70% protection rate for EV71-infected mice, reduced the viral load in liver and heart tissues, and relieved the inflammatory response. A mechanistic study showed that PLX8394 inhibited EV71 by suppressing the RAF/MEK/ERK signaling pathway. Thus, PLX8394 lays a foundation for the development of new drugs against EV71.
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2
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Mariita RM, Davis JH, Randive RV. Illuminating Human Norovirus: A Perspective on Disinfection of Water and Surfaces Using UVC, Norovirus Model Organisms, and Radiation Safety Considerations. Pathogens 2022; 11:pathogens11020226. [PMID: 35215169 PMCID: PMC8879714 DOI: 10.3390/pathogens11020226] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 01/22/2022] [Accepted: 02/03/2022] [Indexed: 02/04/2023] Open
Abstract
Human noroviruses (HuNoVs) are a major cause of gastroenteritis and are associated with high morbidity because of their ability to survive in the environment and small inoculum size required for infection. Norovirus is transmitted through water, food, high touch-surfaces, and human-to-human contact. Ultraviolet Subtype C (UVC) light-emitting diodes (LEDs) can disrupt the norovirus transmission chain for water, food, and surfaces. Here, we illuminate considerations to be adhered to when picking norovirus surrogates for disinfection studies and shine light on effective use of UVC for norovirus infection control in water and air and validation for such systems and explore the blind spot of radiation safety considerations when using UVC disinfection strategies. This perspective also discusses the promise of UVC for norovirus mitigation to save and ease life.
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3
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Smolko CM, Janes KA. An ultrasensitive fiveplex activity assay for cellular kinases. Sci Rep 2019; 9:19409. [PMID: 31857650 PMCID: PMC6923413 DOI: 10.1038/s41598-019-55998-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 09/30/2019] [Indexed: 02/06/2023] Open
Abstract
Protein kinases are enzymes whose abundance, protein-protein interactions, and posttranslational modifications together determine net signaling activity in cells. Large-scale data on cellular kinase activity are limited, because existing assays are cumbersome, poorly sensitive, low throughput, and restricted to measuring one kinase at a time. Here, we surmount the conventional hurdles of activity measurement with a multiplexing approach that leverages the selectivity of individual kinase-substrate pairs. We demonstrate proof of concept by designing an assay that jointly measures activity of five pleiotropic signaling kinases: Akt, IκB kinase (IKK), c-jun N-terminal kinase (JNK), mitogen-activated protein kinase (MAPK)-extracellular regulated kinase kinase (MEK), and MAPK-activated protein kinase-2 (MK2). The assay operates in a 96-well format and specifically measures endogenous kinase activation with coefficients of variation less than 20%. Multiplex tracking of kinase-substrate pairs reduces input requirements by 25-fold, with ~75 µg of cellular extract sufficient for fiveplex activity profiling. We applied the assay to monitor kinase signaling during coxsackievirus B3 infection of two different host-cell types and identified multiple differences in pathway dynamics and coordination that warrant future study. Because the Akt–IKK–JNK–MEK–MK2 pathways regulate many important cellular functions, the fiveplex assay should find applications in inflammation, environmental-stress, and cancer research.
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Affiliation(s)
- Christian M Smolko
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, 22908, USA
| | - Kevin A Janes
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, 22908, USA. .,Department of Biochemistry & Molecular Genetics, University of Virginia, Charlottesville, VA, 22908, USA.
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4
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Kraft L, Erdenesukh T, Sauter M, Tschöpe C, Klingel K. Blocking the IL-1β signalling pathway prevents chronic viral myocarditis and cardiac remodeling. Basic Res Cardiol 2019; 114:11. [DOI: 10.1007/s00395-019-0719-0] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 01/16/2019] [Indexed: 12/18/2022]
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5
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The Dietary Restriction-Like Gene drl-1, Which Encodes a Putative Serine/Threonine Kinase, Is Essential for Orsay Virus Infection in Caenorhabditis elegans. J Virol 2019; 93:JVI.01400-18. [PMID: 30429346 DOI: 10.1128/jvi.01400-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Accepted: 11/07/2018] [Indexed: 12/16/2022] Open
Abstract
Orsay virus is the only known natural virus pathogen of Caenorhabditis elegans, and its discovery has enabled virus-host interaction studies in this model organism. Host genes required for viral infection remain understudied. We previously established a forward genetic screen based on a virus-inducible green fluorescent protein transcriptional reporter to identify novel host factors essential for virus infection. Here, we report the essential role in Orsay virus infection of the dietary restriction-like (drl-1) gene, which encodes a serine/threonine kinase similar to the mammalian MEKK3 kinase. Ablation of drl-1 led to a >10,000-fold reduction in Orsay virus RNA levels, which could be rescued by ectopic expression of DRL-1. DRL-1 was dispensable for Orsay replication from an endogenous transgene replicon, suggesting that DRL-1 affects a prereplication stage of the Orsay life cycle. Thus, this study demonstrates the power of C. elegans as a model to identify novel virus-host interactions essential for virus infection.IMPORTANCE The recent discovery of Orsay virus, the only known natural virus of Caenorhabditis elegans, provides a unique opportunity to study virus-host interactions that mediate infection in a genetically tractable multicellular model organism. As viruses remain a global threat to human health, better insights into cellular components that enable virus infection and replication can ultimately lead to the development of new targets for antiviral therapeutics.
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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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Nyalwidhe JO, Gallagher GR, Glenn LM, Morris MA, Vangala P, Jurczyk A, Bortell R, Harlan DM, Wang JP, Nadler JL. Coxsackievirus-Induced Proteomic Alterations in Primary Human Islets Provide Insights for the Etiology of Diabetes. J Endocr Soc 2017; 1:1272-1286. [PMID: 29264452 PMCID: PMC5686651 DOI: 10.1210/js.2017-00278] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 09/06/2017] [Indexed: 12/15/2022] Open
Abstract
Enteroviral infections have been associated with the development of type 1 diabetes (T1D), a chronic inflammatory disease characterized by autoimmune destruction of insulin-producing pancreatic beta cells. Cultured human islets, including the insulin-producing beta cells, can be infected with coxsackievirus B4 (CVB4) and thus are useful for understanding cellular responses to infection. We performed quantitative mass spectrometry analysis on cultured primary human islets infected with CVB4 to identify molecules and pathways altered upon infection. Corresponding uninfected controls were included in the study for comparative protein expression analyses. Proteins were significantly and differentially regulated in human islets challenged with virus compared with their uninfected counterparts. Complementary analyses of gene transcripts in CVB4-infected primary islets over a time course validated the induction of RNA transcripts for many of the proteins that were increased in the proteomics studies. Notably, infection with CVB4 results in a considerable decrease in insulin. Genes/proteins modulated during CVB4 infection also include those involved in activation of immune responses, including type I interferon pathways linked to T1D pathogenesis and with antiviral, cell repair, and inflammatory properties. Our study applies proteomics analyses to cultured human islets challenged with virus and identifies target proteins that could be useful in T1D interventions.
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Affiliation(s)
- Julius O Nyalwidhe
- Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, Virginia 23501.,Leroy T. Canoles Jr. Cancer Research Center, Eastern Virginia Medical School, Norfolk, Virginia 23501
| | - Glen R Gallagher
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Lindsey M Glenn
- Department of Internal Medicine and Strelitz Diabetes Center, Eastern Virginia Medical School, Norfolk, Virginia 23501
| | - Margaret A Morris
- Department of Internal Medicine and Strelitz Diabetes Center, Eastern Virginia Medical School, Norfolk, Virginia 23501
| | - Pranitha Vangala
- Department of Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Agata Jurczyk
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Rita Bortell
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - David M Harlan
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Jennifer P Wang
- Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Jerry L Nadler
- Department of Internal Medicine and Strelitz Diabetes Center, Eastern Virginia Medical School, Norfolk, Virginia 23501
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Duan H, Zhu M, Xiong Q, Wang Y, Xu C, Sun J, Wang C, Zhang H, Xu P, Peng Y. Regulation of enterovirus 2A protease-associated viral IRES activities by the cell's ERK signaling cascade: Implicating ERK as an efficiently antiviral target. Antiviral Res 2017; 143:13-21. [PMID: 28351508 DOI: 10.1016/j.antiviral.2017.03.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 03/22/2017] [Accepted: 03/24/2017] [Indexed: 10/19/2022]
Abstract
In a previous study the ERK1/2 pathway was found to be crucially involved in positive regulation of the enterovirus A 71(EV-A71) IRES (vIRES), thereby contributing to the efficient replication of an important human enterovirus causing death in young children (<5yrs) worldwide. This study focuses on unraveling more about the detailed mechanism of ERK's involvement in this regulation of vIRES. Through the use of siRNAs and specifically pharmacological inhibitor U0126, the ERK cascade was shown to positively regulate EV-A71-mediated cleavage of eIF4GI that established the cellular conditions which favour vIRES-dependent translation. Site-directed mutagenesis of the viral 2A protease (2Apro) was undertaken to show that the positive regulation of virus replication by the ERK cascade was mediated through effects on both the cis-cleavage of the viral polyprotein by 2Apro and its trans-cleavage of cellular eIF4GI. This ERK-2Apro linked network coordinating vIRES efficiency was also found in other important human enteroviruses. This identification of the ERK cascade as having a key role in maintaining the 2Apro proteolytic activity required to maximize enterovirus IRES activity, expands current understanding of the diverse functions of the ERK signaling cascade in the regulation of viral translation, therefore providing a potentially comprehensive drug target for anti-enterovirus infection.
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Affiliation(s)
- Hao Duan
- Department of Microbiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Meng Zhu
- Department of Microbiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Qing Xiong
- Department of Microbiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Yuya Wang
- Department of Microbiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Chao Xu
- Department of Microbiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Jing Sun
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Medicinal Chemistry, School of Pharmaceutical Science, Peking University Health Science Center, Beijing 100191, China
| | - Chao Wang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Medicinal Chemistry, School of Pharmaceutical Science, Peking University Health Science Center, Beijing 100191, China
| | - Hao Zhang
- Department of Microbiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Ping Xu
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Medicinal Chemistry, School of Pharmaceutical Science, Peking University Health Science Center, Beijing 100191, China
| | - Yihong Peng
- Department of Microbiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China.
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Shah M, Smolko CM, Kinicki S, Chapman ZD, Brautigan DL, Janes KA. Profiling Subcellular Protein Phosphatase Responses to Coxsackievirus B3 Infection of Cardiomyocytes. Mol Cell Proteomics 2017; 16:S244-S262. [PMID: 28174228 DOI: 10.1074/mcp.o116.063487] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 01/31/2017] [Indexed: 01/23/2023] Open
Abstract
Cellular responses to stimuli involve dynamic and localized changes in protein kinases and phosphatases. Here, we report a generalized functional assay for high-throughput profiling of multiple protein phosphatases with subcellular resolution and apply it to analyze coxsackievirus B3 (CVB3) infection counteracted by interferon signaling. Using on-plate cell fractionation optimized for adherent cells, we isolate protein extracts containing active endogenous phosphatases from cell membranes, the cytoplasm, and the nucleus. The extracts contain all major classes of protein phosphatases and catalyze dephosphorylation of plate-bound phosphosubstrates in a microtiter format, with cellular activity quantified at the end point by phosphospecific ELISA. The platform is optimized for six phosphosubstrates (ERK2, JNK1, p38α, MK2, CREB, and STAT1) and measures specific activities from extracts of fewer than 50,000 cells. The assay was exploited to examine viral and antiviral signaling in AC16 cardiomyocytes, which we show can be engineered to serve as susceptible and permissive hosts for CVB3. Phosphatase responses were profiled in these cells by completing a full-factorial experiment for CVB3 infection and type I/II interferon signaling. Over 850 functional measurements revealed several independent, subcellular changes in specific phosphatase activities. During CVB3 infection, we found that type I interferon signaling increases subcellular JNK1 phosphatase activity, inhibiting nuclear JNK1 activity that otherwise promotes viral protein synthesis in the infected host cell. Our assay provides a high-throughput way to capture perturbations in important negative regulators of intracellular signal-transduction networks.
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Affiliation(s)
- Millie Shah
- From the ‡Department of Biomedical Engineering
| | | | | | | | - David L Brautigan
- the ‖Center for Cell Signaling and Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville, Virginia 22908
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Li X, Kong J, Meng X, Luo K, Luan S, Cao B, Liu N. Isolation and expression analysis of an MAPKK gene from Fenneropenaeus chinensis in response to white spot syndrome virus infection. FISH & SHELLFISH IMMUNOLOGY 2016; 55:116-122. [PMID: 27164214 DOI: 10.1016/j.fsi.2016.05.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 05/04/2016] [Accepted: 05/05/2016] [Indexed: 06/05/2023]
Abstract
Mitogen-activated kinase kinase (MAPKK) is an important gene involved in the host-virus interaction process. To obtain a better understanding of MAPKK in the interaction process between the Chinese shrimp Fenneropenaeus chinensis and white spot syndrome virus (WSSV), we cloned the sequence of an MAPKK cDNA from F. chinensis (FcMAPKK) and investigated the effect of FcMAPKK on WSSV infection. The results showed that the FcMAPKK gene contained a 1227 bp open reading frame (ORF), which encoded a highly conserved protein with a serine/threonine protein kinase catalytic (S_TKc) domain. The deduced amino acid sequence of FcMAPKK shared identities between 11.9 and 92.6% with MAPKKs from vertebrate, invertebrate, plant and fungus species. The FcMAPKK was expressed in all the examined tissues in the normal F. chinensis. FcMAPKK expression level was highest in the hepatopancreas where it was approximately 2.6-fold the expression level in the gill, and lowest in the muscle where it was approximately 0.3-fold the expression level in the hepatopancreas. The FcMAPKK expression levels in the muscle, gill, and hepatopancreas were all changed post WSSV challenge. The FcMAPKK expression was significantly (P < 0.01) up-regulated in the muscle of F. chinensis at 48 h post WSSV infection. The WSSV began to replicate quickly in the normal F. chinensis at 48 h post infection, while the WSSV replication in the U0126-treated F. chinensis could be significantly (P < 0.05) inhibited. The results suggested that FcMAPKK might be involved in the WSSV infection process, and hijacking of FcMAPKK might be required for WSSV replication in F. chinensis.
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Affiliation(s)
- Xupeng Li
- Key Laboratory for Sustainable Utilization of Marine Fisheries Resources, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 106 Nanjing Road, Qingdao, 266071, PR China
| | - Jie Kong
- Key Laboratory for Sustainable Utilization of Marine Fisheries Resources, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 106 Nanjing Road, Qingdao, 266071, PR China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, 1 Wenhai Road, Qingdao, 266300, PR China.
| | - Xianhong Meng
- Key Laboratory for Sustainable Utilization of Marine Fisheries Resources, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 106 Nanjing Road, Qingdao, 266071, PR China
| | - Kun Luo
- Key Laboratory for Sustainable Utilization of Marine Fisheries Resources, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 106 Nanjing Road, Qingdao, 266071, PR China
| | - Sheng Luan
- Key Laboratory for Sustainable Utilization of Marine Fisheries Resources, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 106 Nanjing Road, Qingdao, 266071, PR China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, 1 Wenhai Road, Qingdao, 266300, PR China
| | - Baoxiang Cao
- Key Laboratory for Sustainable Utilization of Marine Fisheries Resources, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 106 Nanjing Road, Qingdao, 266071, PR China
| | - Ning Liu
- Key Laboratory for Sustainable Utilization of Marine Fisheries Resources, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, 106 Nanjing Road, Qingdao, 266071, PR China
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Effects of Synthetic Anti-Inflammatory Sterol in CB3V-Induced Myocarditis: A Morphological Study on Heart Muscle Tissue. J Funct Morphol Kinesiol 2016. [DOI: 10.3390/jfmk1010069] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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12
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Xin L, Ma X, Xiao Z, Yao H, Liu Z. Coxsackievirus B3 induces autophagy in HeLa cells via the AMPK/MEK/ERK and Ras/Raf/MEK/ERK signaling pathways. INFECTION GENETICS AND EVOLUTION 2015; 36:46-54. [PMID: 26305625 DOI: 10.1016/j.meegid.2015.08.026] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 05/09/2015] [Revised: 08/17/2015] [Accepted: 08/20/2015] [Indexed: 12/19/2022]
Abstract
In a previous study, the number of autophagosomes increased after coxsackievirus B3 (CVB3) infection. However, the exact mechanism by which CVB3 regulates the number of autophagosomes is unclear. Earlier studies have found that infection with CVB3 activates extracellular signal-regulated kinase (ERK). ERK is essential for CVB3 replication and can increase the number of autophagosomes. In the current study, extracellular signal-regulated kinase 1/2 was activated in HeLa cells after CVB3 infection. The ERK kinase inhibitor, U0126, was then used to inhibit the activity of ERK. Treatment with U0126 led to a significant reduction in the number of autophagosomes indicating that the CVB3-induced autophagosome accumulation may have occurred via the ERK pathway. The relationship between CVB3 infection and ERK pathway activation was also investigated. The results showed that the RasGAP protein could be further cleaved, leading to the activation of the Ras/Raf/MEK (mitogen/extracellular signal-regulated kinase)/ERK pathway and that CVB3 infection could result in an increase in the concentration of calcium in the cytoplasm, resulting in mitochondrial damage, a decrease in the concentration of ATP and activation of the AMPK (AMP-activated protein kinase)/MEK/ERK pathway. In summary, CVB3 might directly or indirectly induce autophagy via AMPK/MEK/ERK and Ras/Raf/MEK/ERK signaling pathways in the host cells, representing a pivotal mechanism for CVB3 pathogenesis.
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Affiliation(s)
- Le Xin
- Department of Molecular Immunology, Capital Institute of Pediatrics, China
| | - Xiaolin Ma
- Department of Molecular Immunology, Capital Institute of Pediatrics, China
| | - Zonghui Xiao
- Department of Molecular Immunology, Capital Institute of Pediatrics, China
| | - Hailan Yao
- Department of Molecular Immunology, Capital Institute of Pediatrics, China.
| | - Zhewei Liu
- Department of Molecular Immunology, Capital Institute of Pediatrics, China.
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Zhang H, Cong H, Song L, Tien P. The nuclear protein Sam68 is redistributed to the cytoplasm and is involved in PI3K/Akt activation during EV71 infection. Virus Res 2014; 180:1-11. [DOI: 10.1016/j.virusres.2013.11.020] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 11/09/2013] [Accepted: 11/26/2013] [Indexed: 10/25/2022]
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14
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Henke A, Jarasch N, Wutzler P. Coxsackievirus B3 vaccines: use as an expression vector for prevention of myocarditis. Expert Rev Vaccines 2014; 7:1557-67. [DOI: 10.1586/14760584.7.10.1557] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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15
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Ye X, Hemida MG, Qiu Y, Hanson PJ, Zhang HM, Yang D. MiR-126 promotes coxsackievirus replication by mediating cross-talk of ERK1/2 and Wnt/β-catenin signal pathways. Cell Mol Life Sci 2013; 70:4631-44. [PMID: 23811937 PMCID: PMC11113642 DOI: 10.1007/s00018-013-1411-4] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 06/10/2013] [Accepted: 06/17/2013] [Indexed: 12/11/2022]
Abstract
Coxsackievirus B3 (CVB3) is one of the most prevalent causes of viral myocarditis and is associated with many other pathological conditions. CVB3 replication relies on host cellular machineries and causes direct damage to host cells. MicroRNAs have been found to regulate viral infections but their roles in CVB3 infection are still poorly understood. Here we describe a novel mechanism by which miR-126 regulates two signal pathways essential for CVB3 replication. We found that CVB3-induced ERK1/2 activation triggered the phosphorylation of ETS-1 and ETS-2 transcription factors, which induced miR-126 upregulation. By using both microRNA mimics and inhibitors, we proved that the upregulated miR-126 suppressed sprouty-related, EVH1 domain containing 1 (SPRED1) and in turn enhanced ERK1/2 activation. This positive feedback loop of ERK1/2-miR-126-ERK1/2 promoted CVB3 replication. Meanwhile, miR-126 expression stimulated GSK-3β activity and induced degradation of β-catenin through suppressing LRP6 and WRCH1, two newly identified targets in the Wnt/β-catenin pathway, which sensitized the cells to virus-induced cell death and increased viral progeny release to initiate new infections. Our results demonstrate that upregulated miR-126 upon CVB3 infection targets SPRED1, LRP6, and WRCH1 genes, mediating cross-talk between ERK1/2 and Wnt/β-catenin pathways, and thus promoting viral replication and contributes to the viral cytopathogenicity.
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Affiliation(s)
- Xin Ye
- Department of Pathology and Laboratory Medicine, The Institute for Heart and Lung Health, St. Paul’s Hospital, University of British Columbia, Rm 166, 1081 Burrard Street, Vancouver, BC V6Z1Y6 Canada
| | - Maged Gomaa Hemida
- Department of Pathology and Laboratory Medicine, The Institute for Heart and Lung Health, St. Paul’s Hospital, University of British Columbia, Rm 166, 1081 Burrard Street, Vancouver, BC V6Z1Y6 Canada
| | - Ye Qiu
- Department of Pathology and Laboratory Medicine, The Institute for Heart and Lung Health, St. Paul’s Hospital, University of British Columbia, Rm 166, 1081 Burrard Street, Vancouver, BC V6Z1Y6 Canada
| | - Paul J. Hanson
- Department of Pathology and Laboratory Medicine, The Institute for Heart and Lung Health, St. Paul’s Hospital, University of British Columbia, Rm 166, 1081 Burrard Street, Vancouver, BC V6Z1Y6 Canada
| | - Huifang Mary Zhang
- Department of Pathology and Laboratory Medicine, The Institute for Heart and Lung Health, St. Paul’s Hospital, University of British Columbia, Rm 166, 1081 Burrard Street, Vancouver, BC V6Z1Y6 Canada
| | - Decheng Yang
- Department of Pathology and Laboratory Medicine, The Institute for Heart and Lung Health, St. Paul’s Hospital, University of British Columbia, Rm 166, 1081 Burrard Street, Vancouver, BC V6Z1Y6 Canada
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16
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Jensen KJ, Garmaroudi FS, Zhang J, Lin J, Boroomand S, Zhang M, Luo Z, Yang D, Luo H, McManus BM, Janes KA. An ERK-p38 subnetwork coordinates host cell apoptosis and necrosis during coxsackievirus B3 infection. Cell Host Microbe 2013; 13:67-76. [PMID: 23332156 DOI: 10.1016/j.chom.2012.11.009] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Revised: 08/30/2012] [Accepted: 11/12/2012] [Indexed: 11/17/2022]
Abstract
The host response to a virus is determined by intracellular signaling pathways that are modified during infection. These pathways converge as networks and produce interdependent phenotypes, making it difficult to link virus-induced signals and responses at a systems level. Coxsackievirus B3 (CVB3) infection induces death of cardiomyocytes, causing tissue damage and virus dissemination, through incompletely characterized host cell signaling networks. We built a statistical model that quantitatively predicts cardiomyocyte responses from time-dependent measurements of phosphorylation events modified by CVB3. Model analysis revealed that CVB3-stimulated cytotoxicity involves tight coupling between the host ERK and p38 MAPK pathways, which are generally thought to control distinct cellular responses. The kinase ERK5 requires p38 kinase activity and inhibits apoptosis caused by CVB3 infection. By contrast, p38 indirectly promotes apoptosis via ERK1/2 inhibition but directly causes CVB3-induced necrosis. Thus, the cellular events governing pathogenesis are revealed when virus-host programs are monitored systematically and deconvolved mathematically.
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Affiliation(s)
- Karin J Jensen
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, USA
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17
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Gruhle S, Sauter M, Szalay G, Ettischer N, Kandolf R, Klingel K. The prostacyclin agonist iloprost aggravates fibrosis and enhances viral replication in enteroviral myocarditis by modulation of ERK signaling and increase of iNOS expression. Basic Res Cardiol 2012; 107:287. [PMID: 22836587 DOI: 10.1007/s00395-012-0287-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Revised: 07/06/2012] [Accepted: 07/13/2012] [Indexed: 12/19/2022]
Abstract
Enteroviruses, such as coxsackieviruses of group B (CVB), are able to induce a chronic inflammation of the myocardium, which may finally lead to the loss of functional tissue, remodeling processes and the development of fibrosis, thus affecting the proper contractile function of the heart. In other fibrotic diseases like scleroderma, the prostacyclin agonist iloprost was found to inhibit the extracellular signal-regulated kinase (ERK, p44/42 MAPK), a mitogen-activated protein kinase, and consecutively, the expression of the profibrotic cytokine connective tissue growth factor (CTGF), thereby preventing the development of fibrosis. As CTGF was found to mediate fibrosis in chronic CVB3 myocarditis as well, we evaluated whether the in vivo application of iloprost is capable to reduce the development of ERK/CTGF-mediated fibrosis in enteroviral myocarditis. Unexpectedly, the application of iloprost resulted in a prolonged myocardial inflammation and an aggravated fibrosis and failed to reduce activation of ERK and expression of CTGF at later stages of the disease. In addition, viral replication was found to be increased in iloprost-treated mice. Notably, the expression of cardiac inducible nitric oxide synthase (iNOS), which is known to aggravate myocardial damage in CVB3-infected mice, was strongly enhanced by iloprost. Using cultivated bone marrow macrophages (BMM), we confirmed these results, proving that iloprost potentiates the expression of iNOS mRNA and protein in CVB3-infected and IFN-gamma stimulated BMM. In conclusion, these results suggest a critical reflection of the clinical use of iloprost, especially in patients possibly suffering from an enteroviral myocarditis.
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Affiliation(s)
- Stefan Gruhle
- Department of Molecular Pathology, Institute for Pathology and Neuropathology, University Hospital Tübingen, Liebermeisterstrasse 8, Tübingen, Germany
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18
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Lawrence P, Schafer EA, Rieder E. The nuclear protein Sam68 is cleaved by the FMDV 3C protease redistributing Sam68 to the cytoplasm during FMDV infection of host cells. Virology 2012; 425:40-52. [PMID: 22280896 DOI: 10.1016/j.virol.2011.12.019] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Revised: 11/23/2011] [Accepted: 12/31/2011] [Indexed: 01/28/2023]
Abstract
Picornavirus infection can lead to disruption of nuclear pore traffic, shut-off of cell translation machinery, and cleavage of proteins involved in cellular signal transduction and the innate response to infection. Here, we demonstrated that the FMDV 3C(pro) induced the cleavage of nuclear RNA-binding protein Sam68 C-terminus containing the nuclear localization sequence (NLS). Consequently, it stimulated the redistribution of Sam68 to the cytoplasm. The siRNA knockdown of Sam68 resulted in a 1000-fold reduction in viral titers, which prompted us to study the effect of Sam68 on FMDV post-entry events. Interestingly, Sam68 interacts with the internal ribosomal entry site within the 5' non-translated region of the FMDV genome, and Sam68 knockdown decreased FMDV IRES-driven activity in vitro suggesting that it could modulate translation of the viral genome. The results uncover a novel role for Sam68 in the context of picornaviruses and the proteolysis of a new cellular target of the FMDV 3C(pro).
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Affiliation(s)
- Paul Lawrence
- Foreign Animal Disease Research Unit, United States Department of Agriculture, Agricultural Research Service, Plum Island Animal Disease Center, Greenport, NY 11944, USA
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19
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Activation of the Ras/Raf/MEK pathway facilitates hepatitis C virus replication via attenuation of the interferon-JAK-STAT pathway. J Virol 2011; 86:1544-54. [PMID: 22114332 DOI: 10.1128/jvi.00688-11] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Hepatitis C virus (HCV) is a major cause of chronic liver diseases worldwide, often leading to the development of hepatocellular carcinoma (HCC). Constitutive activation of the Ras/Raf/MEK pathway is responsible for approximately 30% of cancers. Here we attempted to address the correlation between activation of this pathway and HCV replication. We showed that knockdown of Raf1 inhibits HCV replication, while activation of the Ras/Raf/MEK pathway by V12, a constitutively active form of Ras, stimulates HCV replication. We further demonstrated that this effect is regulated through attenuation of the interferon (IFN)-JAK-STAT pathway. Activation of the Ras/Raf/MEK pathway downregulates the expression of IFN-stimulated genes (ISGs), attenuates the phosphorylation of STAT1/2, and inhibits the expression of interferon (alpha, beta, and omega) receptors 1 and 2 (IFNAR1/2). Furthermore, we observed that HCV infection activates the Ras/Raf/MEK pathway. Thus, we propose that during HCV infection, the Ras/Raf/MEK pathway is activated, which in turn attenuates the IFN-JAK-STAT pathway, resulting in stimulation of HCV replication.
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20
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Comparative RNAi screening reveals host factors involved in enterovirus infection of polarized endothelial monolayers. Cell Host Microbe 2011; 9:70-82. [PMID: 21238948 DOI: 10.1016/j.chom.2011.01.001] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Revised: 11/12/2010] [Accepted: 12/14/2010] [Indexed: 11/23/2022]
Abstract
Enteroviruses, including coxsackievirus B (CVB) and poliovirus (PV), can access the CNS through the blood brain barrier (BBB) endothelium to cause aseptic meningitis. To identify cellular components required for CVB and PV infection of human brain microvascular endothelial cells, an in vitro BBB model, we performed comparative RNAi screens and identified 117 genes that influenced infection. Whereas a large proportion of genes whose depletion enhanced infection (17 of 22) were broadly antienteroviral, only 46 of the 95 genes whose depletion inhibited infection were required by both CVB and PV and included components of cell signaling pathways such as adenylate cyclases. Downregulation of genes including Rab GTPases, Src tyrosine kinases, and tyrosine phosphatases displayed specificity in their requirement for either CVB or PV infection. These findings highlight the pathways hijacked by enteroviruses for entry and replication in the BBB endothelium, a specialized and clinically relevant cell type for these viruses.
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21
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Nucleoporin phosphorylation triggered by the encephalomyocarditis virus leader protein is mediated by mitogen-activated protein kinases. J Virol 2010; 84:12538-48. [PMID: 20881039 DOI: 10.1128/jvi.01484-09] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cardioviruses disrupt nucleocytoplasmic transport through the activity of their leader (L) protein. We have shown that hyperphosphorylation of nuclear pore proteins (nucleoporins or Nups), including Nup62, Nup153, and Nup214, is central to this L protein function and requires one or more cytosolic kinases. In this study, potential cellular enzymes involved in encephalomyocarditis virus (EMCV) L-directed Nup phosphorylation were screened with a panel of specific, cell-permeating kinase inhibitors. Extracellular signal-regulated receptor kinase (ERK) and p38 mitogen-activated protein kinase inhibitors (U0126 and SB203580) were sufficient to block Nup hyperphosphorylation in EMCV-infected or L-expressing cells. Recombinant L alone, in the absence of infection, triggered activation of ERK and p38, independent of their upstream signaling cascades. Conserved residues within the L zinc finger (Cys(19)) and acidic domain (Asp(48),(51),(52),(55)) were essential for this activation and for the phosphorylation of Nups, suggesting that the phenomena are linked. Analysis of the hyperphosphorylated Nup species revealed only phosphoserine and phosphothreonine residues. The sizes of the tryptic phosphopeptides derived from Nup62 were compatible with sites in the Phe/Gly repeat domain which display common consensus sequences for ERK and p38 substrates. The results provide strong evidence that ERK and p38 are the probable effector kinases required for L-dependent inhibition of nuclear trafficking.
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22
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Lin JY, Chen TC, Weng KF, Chang SC, Chen LL, Shih SR. Viral and host proteins involved in picornavirus life cycle. J Biomed Sci 2009; 16:103. [PMID: 19925687 PMCID: PMC2785775 DOI: 10.1186/1423-0127-16-103] [Citation(s) in RCA: 131] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2009] [Accepted: 11/20/2009] [Indexed: 01/11/2023] Open
Abstract
Picornaviruses cause several diseases, not only in humans but also in various animal hosts. For instance, human enteroviruses can cause hand-foot-and-mouth disease, herpangina, myocarditis, acute flaccid paralysis, acute hemorrhagic conjunctivitis, severe neurological complications, including brainstem encephalitis, meningitis and poliomyelitis, and even death. The interaction between the virus and the host is important for viral replication, virulence and pathogenicity. This article reviews studies of the functions of viral and host factors that are involved in the life cycle of picornavirus. The interactions of viral capsid proteins with host cell receptors is discussed first, and the mechanisms by which the viral and host cell factors are involved in viral replication, viral translation and the switch from translation to RNA replication are then addressed. Understanding how cellular proteins interact with viral RNA or viral proteins, as well as the roles of each in viral infection, will provide insights for the design of novel antiviral agents based on these interactions.
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Affiliation(s)
- Jing-Yi Lin
- Research Center for Emerging Viral Infections, Chang Gung University, Tao-Yuan, Taiwan.
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23
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Kandolf R, Bültmann B, Klingel K, Bock CT. [Molecular mechanisms and consequences of cardiac viral infections]. DER PATHOLOGE 2009; 29 Suppl 2:112-7. [PMID: 18820926 DOI: 10.1007/s00292-008-1027-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Molecular biological methods have confirmed the pathogenetic role of enteroviruses, primarily coxsackieviruses of group B (CVB), in the induction and maintenance of inflammatory cardiomyopathy. More recently, adenoviruses, various herpes viruses, and increasingly parvovirus B19 (B19) have been identified as potential cardiotropic agents. While cardiac myocytes are target cells for enterovirus and adenovirus infections with virus-induced cytolysis, B19-associated inflammatory cardiomyopathy is characterized by infection of intracardiac endothelial cells of small arterioles and veins, which may be associated with endothelial dysfunction, impairment of myocardial microcirculation, penetration of inflammatory cells, and secondary myocyte necrosis. Recent observations showed that B19 is involved in intracellular calcium regulation by the viral phospholipase. B19-induced caspase activation can lead to proinflammatory/proapoptotic processes through dysregulation of STAT signaling. These cellular interactions may contribute to mechanisms by which B19 establishes persistent infection in endothelial cells and play a critical role in viral pathogenesis of inflammatory cardiomyopathy.
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Affiliation(s)
- R Kandolf
- Abteilung Molekulare Pathologie, Universitätsklinikum Tübingen, Liebermeisterstrasse 8, 72076 Tübingen.
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24
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Pleschka S. RNA viruses and the mitogenic Raf/MEK/ERK signal transduction cascade. Biol Chem 2008; 389:1273-82. [DOI: 10.1515/bc.2008.145] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
AbstractThe Raf/MEK/ERK signal transduction cascade belongs to the mitogen-activated protein kinase (MAPK) cascades. Raf/MEK/ERK signaling leads to stimulus-specific changes in gene expression, alterations in cell metabolism or induction of programmed cell death (apoptosis), and thus controls cell differentiation and proliferation. It is induced by extracellular agents, including pathogens such as RNA viruses. Many DNA viruses are known to induce cellular signaling via this pathway. As these pathogens partly use the DNA synthesis machinery for their replication, they aim to drive cells into a proliferative state. In contrast, the consequences of RNA virus-induced Raf/MEK/ERK signaling were less clear for a long time, but since the turn of the century the number of publications on this topic has rapidly increased. Research on this virus/host-interaction will broaden our understanding of its relevance in viral replication. This important control center of cellular responses is differently employed to support the replication of several important human pathogenic RNA viruses including influenza, Ebola, hepatitis C and SARS corona viruses.
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25
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Esfandiarei M, McManus BM. Molecular biology and pathogenesis of viral myocarditis. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2008; 3:127-55. [PMID: 18039131 DOI: 10.1146/annurev.pathmechdis.3.121806.151534] [Citation(s) in RCA: 273] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Myocarditis is a cardiac disease associated with inflammation and injury of the myocardium. Several viruses have been associated with myocarditis in humans. However, coxsackievirus B3 is still considered the dominant etiological agent. The observed pathology in viral myocarditis is a result of cooperation or teamwork between viral processes and host immune responses at various stages of disease. Both innate and adaptive immune responses are crucial determinants of the severity of myocardial damage, and contribute to the development of chronic myocarditis and dilated cardiomyopathy following acute viral myocarditis. Advances in genomics and proteomics, and in the use of informatics and biostatistics, are allowing unbiased initial evaluations that can be the basis for testable hypotheses about virus pathogenesis and new therapies.
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Affiliation(s)
- Mitra Esfandiarei
- The James Hogg iCAPTURE Center for Cardiovascular and Pulmonary Research, St. Paul's Hospital, Providence Health Care Research Institute, Vancouver, Canada.
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26
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Iwashita S, Song SY. RasGAPs: a crucial regulator of extracellular stimuli for homeostasis of cellular functions. MOLECULAR BIOSYSTEMS 2008; 4:213-22. [PMID: 18437264 DOI: 10.1039/b716357f] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Ras and its GTPase activating proteins (GAPs) are among the crucial regulators of extracelluar ligands. Information about these regulators has been elucidated during the course of studies in signal transduction over the last two decades. RasGAPs such as p120GAP and neurofibromin have been studied extensively for their roles as either "negative" regulators or effectors of Ras. Accumulating evidence suggests that these molecules are crucial regulators of extracellular stimuli that serve to maintain the homeostasis of cellular functions. This compendium highlights cellular functions of RasGAPs and their signaling characteristics from the viewpoint of homeostasis, including our recent finding of the phenotype of R-RasGAP mutant mice whose GAP activity is down-regulated.
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Affiliation(s)
- Shintaro Iwashita
- Faculty of Pharmacy, Iwaki Meisei University, Iwaki, Fukushima 970-8551, Japan.
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27
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Martin U, Jarasch N, Nestler M, Rassmann A, Munder T, Seitz S, Zell R, Wutzler P, Henke A. Antiviral effects of pan-caspase inhibitors on the replication of coxsackievirus B3. Apoptosis 2007; 12:525-33. [PMID: 17211569 DOI: 10.1007/s10495-006-0015-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2006] [Accepted: 11/14/2006] [Indexed: 11/27/2022]
Abstract
The induction of apoptosis during coxsackievirus B3 (CVB3) infection is well documented. In order to study whether the inhibition of apoptosis has an impact on CVB3 replication, the pan-caspase inhibitor Z-VAD-FMK was used. The decreased CVB3 replication is based on reduced accumulation of both viral RNA and viral proteins. These effects are due to an inhibitory influence of Z-VAD-FMK on the proteolytic activity of the CVB3 proteases 2A and 3C, which was demonstrated by using the target protein poly(A)-binding protein (PABP). The antiviral effect of the structurally different pan-caspase inhibitor Q-VD-OPH was independently of the viral protease inhibition and resulted in suppression of virus progeny production and impaired release of newly produced CVB3 from infected cells. A delayed release of cytochrome c into the cytoplasm was detected in Q-VD-OPH-treated CVB3-infected cells pointing to an involvement of caspases in the initial steps of mitochondrial membrane-permeabilization.
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Affiliation(s)
- Ulrike Martin
- Institute of Virology and Antiviral Therapy, Medical Center, Friedrich Schiller University, Jena, Germany
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28
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Lyman MG, Randall JA, Calton CM, Banfield BW. Localization of ERK/MAP kinase is regulated by the alphaherpesvirus tegument protein Us2. J Virol 2006; 80:7159-68. [PMID: 16809321 PMCID: PMC1489020 DOI: 10.1128/jvi.00592-06] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Many different viruses activate the extracellular signal-regulated kinase (ERK)/mitogen-activated protein (MAP) kinase signaling pathway during infection and require ERK activation for the efficient execution of their replication programs. Despite these findings, no virus-encoded proteins have been identified that directly modulate ERK activities. In an effort to determine the function of a conserved alphaherpesvirus structural protein called Us2, we screened a yeast two-hybrid library derived from NIH 3T3 cells and identified ERK as a Us2-interacting protein. Our studies indicate that Us2 binds to ERK in virus-infected cells, mediates the incorporation of ERK into the virion, and inhibits the activation of ERK nuclear substrates. The association of Us2 with ERK leads to the sequestration of ERK at the plasma membrane and to a perinuclear vesicular compartment, thereby keeping ERK out of the nucleus. Us2 can bind to activated ERK, and the data suggest that Us2 does not inhibit ERK enzymatic activity. The treatment of cells with U0126, a specific inhibitor of ERK activation, resulted in a substantial delay in the release of virus from infected cells that was more pronounced with a virus deleted for Us2 than with parental and repaired strains, suggesting that both ERK and Us2 activities are required for efficient virus replication. This study highlights an additional complexity to the activation of ERK by viruses, namely, that localization of active ERK can be altered by virus-encoded proteins.
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Affiliation(s)
- Mathew G Lyman
- Department of Microbiology, University of Colorado at Denver and Health Sciences Center, Mail Stop 8333, P.O. Box 6511, Aurora, 80045, USA
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29
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Battcock SM, Collier TW, Zu D, Hirasawa K. Negative regulation of the alpha interferon-induced antiviral response by the Ras/Raf/MEK pathway. J Virol 2006; 80:4422-30. [PMID: 16611902 PMCID: PMC1472035 DOI: 10.1128/jvi.80.9.4422-4430.2006] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Interferon (IFN) is one of the molecules released by virus-infected cells, resulting in the establishment of an antiviral state within infected and neighboring cells. IFN-induced antiviral response may be subject to modulation by the cellular signaling environment of host cells which impact the effectiveness of viral replication. Here, we show that cells with an activated Ras/Raf/MEK signaling cascade allow propagation of viruses in the presence of IFN. Ras-transformed (RasV12) and vector control NIH 3T3 cells were infected with vesicular stomatitis virus (VSV) or an IFN-sensitive vaccinia virus (delE3L) in the presence of alpha interferon. While IFN protected vector control cells from infection by both viruses, RasV12 cells were susceptible to viral infection regardless of the presence of IFN. IFN sensitivity was restored in RasV12 cells upon RNA interference (RNAi) knockdown of Ras. We further investigated which elements downstream of Ras are responsible for counteracting IFN-induced antiviral responses. A Ras effector domain mutant that can only stimulate the Raf kinase family of effectors was able to suppress the IFN response and allow VSV replication. IFN-induced antiviral mechanisms were also restored in RasV12 cells by treatment with a MEK inhibitor (U0126 or PD98059). Moreover, by using RNAi to MEK1 and MEK2, we determined that MEK2, rather than MEK1, is responsible for suppression of the IFN response. In conclusion, our results suggest that activation of the Ras/Raf/MEK pathway downregulates IFN-induced antiviral response.
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Affiliation(s)
- Sarah M Battcock
- Division of Basic Medical Sciences, Faculty of Medicine, Memorial University of Newfoundland, Rm. 1810, 300 Prince Philip Dr., St. John's A1B3V6, Canada
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30
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Lim BK, Nam JH, Gil CO, Yun SH, Choi JH, Kim DK, Jeon ES. Coxsackievirus B3 replication is related to activation of the late extracellular signal-regulated kinase (ERK) signal. Virus Res 2005; 113:153-7. [PMID: 15993506 DOI: 10.1016/j.virusres.2005.04.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2005] [Revised: 04/24/2005] [Accepted: 04/27/2005] [Indexed: 10/25/2022]
Abstract
MAP kinase signaling has been implicated in coxsackievirus B3 (CVB3) pathogenesis and as necessary in the virus lifecycle. We studied the correlation with extracellular signal-regulated kinase 1/2 (ERK1/2) signaling and virus replication in the presence of coxsackievirus and adenovirus receptor (CAR). In CHO cells that do not expressed CAR, specific ERK1/2 phosphorylation (pERK1/2) was not detected, and progeny virus was not produced after infection. By contrast, in HeLa and CHO-CAR cells, which expressed CAR, the specific early and late pERK1/2 at 0.5 and 8 h were induced, and progeny viruses were produced progressively through 24 h after infection. However, when CHO-CAR cells were infected with replication-defective CVB3, specific pERK1/2 was not detected. In addition, when late pERK1/2 is inhibited by the MEK1 inhibitor PD98059, at 4 h after infection, virus replication significantly decreased. Therefore, our findings suggest that early pERK1/2 is a response to virus binding to CAR, whereas late pERK1/2 is related to the viral replication.
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Affiliation(s)
- Byung-Kwan Lim
- Department of Medicine, Sungkyunkwan University School of Medicine, Cardiac and Vascular Center, Samsung Medical Center, 50 Il-Won Dong, Seoul 135-710, South Korea
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31
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Wong WR, Chen YY, Yang SM, Chen YL, Horng JT. Phosphorylation of PI3K/Akt and MAPK/ERK in an early entry step of enterovirus 71. Life Sci 2005; 78:82-90. [PMID: 16150462 PMCID: PMC7094582 DOI: 10.1016/j.lfs.2005.04.076] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2005] [Accepted: 04/08/2005] [Indexed: 11/24/2022]
Abstract
Viruses have been known to subvert the anti-apoptotic pathways of the host cell in order to delay apoptosis. However, the mechanisms utilized by enterovirus 71 (EV71) to mediate anti-apoptotic activity remained undetermined. We observed that EV71 infection induced an early activation of both phosphatidylinositol 3-kinase (PI3K)/Akt and MAPK/ERK signaling pathways. The activity of GSK3β, a downstream target of these pathways, was negatively regulated by the activation of both MAPK/ERK and PI3K/Akt. The phosphorylation of GSK3 could be inhibited by treatment with the specific inhibitors of MAPK/ERK and PI3K/Akt. Other Akt downstream targets, BAD, caspase-9 and the Forkhead transcription factor (FKHR), were not phosphorylated during the course of infection by EV71. We further demonstrated that infection by UV-irradiated, inactivated virus triggered early Akt activation but was insufficient to trigger late Akt activation. These data suggest that with the phosphorylation of MAPK/ERK and PI3K/Akt the subsequent inactivation of GSK3β is utilized by EV71 as a potential mechanism to delay host cell apoptosis.
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Affiliation(s)
- Wen-Rou Wong
- Department of Dermatology, Chang Gung Memorial Hospital, 199 Tung-Hwa North Road, Taipei 105, Taiwan
| | - Yu-Yun Chen
- Department of Biochemistry, Chang Gung University, 259 Wen-Hwa First Road, Kweishan, Taoyuan 333, Taiwan
| | - Shun-Min Yang
- Department of Biochemistry, Chang Gung University, 259 Wen-Hwa First Road, Kweishan, Taoyuan 333, Taiwan
| | - Yin-Li Chen
- Department of Biochemistry, Chang Gung University, 259 Wen-Hwa First Road, Kweishan, Taoyuan 333, Taiwan
| | - Jim-Tong Horng
- Department of Biochemistry, Chang Gung University, 259 Wen-Hwa First Road, Kweishan, Taoyuan 333, Taiwan
- Chang Gung Bioinformatics Center, Chang Gung University, 259 Wen-Hwa first Road, Taoyuan 333, Taiwan
- Corresponding author. Department of Biochemistry, Chang Gung University, 259 Wen-Hwa First Road, Kweishan, Taoyuan 333, Taiwan. Tel./fax: +886 3 2118407.
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32
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Si X, McManus BM, Zhang J, Yuan J, Cheung C, Esfandiarei M, Suarez A, Morgan A, Luo H. Pyrrolidine dithiocarbamate reduces coxsackievirus B3 replication through inhibition of the ubiquitin-proteasome pathway. J Virol 2005; 79:8014-23. [PMID: 15956547 PMCID: PMC1143712 DOI: 10.1128/jvi.79.13.8014-8023.2005] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Coxsackievirus B3 (CVB3) is one of the most common pathogens for viral myocarditis. The lack of effective therapeutics for CVB3-caused viral diseases underscores the importance of searching for antiviral compounds. Pyrrolidine dithiocarbamate (PDTC) is an antioxidant and is recently reported to inhibit ubiquitin-proteasome-mediated proteolysis. Previous studies have shown that PDTC inhibits replication of rhinovirus, influenza virus, and poliovirus. In the present study, we report that PDTC is a potent inhibitor of CVB3. Coxsackievirus-infected HeLa cells treated with PDTC showed a significant reduction of CVB3 viral RNA synthesis, viral protein VP1 expression, and viral progeny release. Similar to previous observation that divalent ions mediate the function of PDTC, we further report that serum-containing copper and zinc are required for its antiviral activity. CVB3 infection resulted in massive generation of reactive oxygen species (ROS). Although PDTC alleviated ROS generation, the antiviral activity was unlikely dependent on its antioxidant effect because the potent antioxidant, N-acetyl-L-cysteine, failed to inhibit CVB3 replication. Consistent with previous reports that PDTC inhibits ubiquitin-proteasome-mediated protein degradation, we found that PDTC treatment led to the accumulation of several short-lived proteins in infected cells. We further provide evidence that the inhibitory effect of PDTC on protein degradation was not due to inhibition of proteasome activity but likely modulation of ubiquitination. Together with our previous findings that proteasome inhibition reduces CVB3 replication (H. Luo, J. Zhang, C. Cheung, A. Suarez, B. M. McManus, and D. Yang, Am. J. Pathol. 163:381-385, 2003), results in this study suggest a strong antiviral effect of PDTC on coxsackievirus, likely through inhibition of the ubiquitin-proteasome pathway.
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Affiliation(s)
- Xiaoning Si
- Department of Pathology and Laboratory Medicine, The James HoggiCAPTURE Centre for Cardiovascular and Pulmonary Research, University of British Columbia-St. Paul's Hospital, Vancouver, British Columbia, Canada V6Z 1Y6
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Kühl U, Pauschinger M, Noutsias M, Seeberg B, Bock T, Lassner D, Poller W, Kandolf R, Schultheiss HP. High prevalence of viral genomes and multiple viral infections in the myocardium of adults with "idiopathic" left ventricular dysfunction. Circulation 2005; 111:887-93. [PMID: 15699250 DOI: 10.1161/01.cir.0000155616.07901.35] [Citation(s) in RCA: 465] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND For a long time, enteroviruses have been considered to be the most common cause of acute viral myocarditis (MC), with possible transition from MC to dilated cardiomyopathy (DCM). Recent investigations have shown, however, that other viruses are also frequently encountered in MC patients, suggesting that persistence of various virus species may play a pathogenic role in the transition from MC to DCM. The purpose of this study was to screen endomyocardial biopsies (EMBs) from patients with "idiopathic" DCM for the presence of viral genomes by using polymerase chain reaction (PCR) to assess the frequency of cardiac viral infections that may be involved in the pathogenesis of the disease. METHODS AND RESULTS EMBs were obtained for PCR analysis from 245 consecutive patients (median left ventricular ejection fraction, 35.0%; range, 9% to 59%). PCR and reverse transcription-PCR were performed to detect the genomic sequences of enterovirus (EV), adenovirus (ADV), human cytomegalovirus (HCMV), herpes simplex virus, Epstein-Barr virus (EBV), human herpesvirus 6 (HHV-6), parvovirus B19 (PVB19), and influenza A and B viruses. Myocardial inflammation was assessed by histological and immunohistological analyses. Viral genomes could be amplified from EMBs of 165 (67.4%) of the 245 DCM patients: EV=23 (9.4%), ADV=4 (1.6%), PVB19=126 (51.4%), HHV-6=53 (21.6%), EBV=5 (2.0%), HCMV=2 (0.8%), including n=45 cases (27.3%) with multiple infections. Active or borderline myocarditis according to the Dallas classification did not exist in any case. Lymphocyte and macrophage infiltrates were not significantly different in virus-positive versus virus-negative patients. CONCLUSIONS Viral genomes were frequently detected in EMBs of patients with systolic left ventricular dysfunction. Our data suggest that myocardial persistence of various viruses, often presenting as multiple infections, may play a role in the pathogenesis of DCM far more frequently than suspected so far.
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Affiliation(s)
- Uwe Kühl
- Charite-University Medicine Berlin, Campus Benjamin Franklin, Department of Cardiology and Pneumology, Hindenburgdamm 30, 12200 Berlin, Germany.
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Abstract
The small GTPases of the Ras superfamily mediate numerous biological processes through their ability to cycle between an inactive GDP-bound and an active GTP-bound form. Among the key regulators of GTPase cycling are the GTPase-activating proteins (GAPs), which stimulate the weak intrinsic GTP-hydrolysis activity of the GTPases, thereby inactivating them. Despite the abundance of GAPs and the fact that mutations in GAP-encoding genes underlie several human diseases, these proteins have received relatively little attention. Recent studies have addressed the regulatory mechanisms that influence GAP activity. So far, findings suggest that GAP activity is regulated by several mechanisms, including protein-protein interactions, phospholipid interactions, phosphorylation, subcellular translocation and proteolytic degradation.
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Affiliation(s)
- Andre Bernards
- MGH Cancer Center and Harvard Medical School, 149 13th Street, Charlestown, MA 02129, USA
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35
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Shen Y, Xu W, Chu YW, Wang Y, Liu QS, Xiong SD. Coxsackievirus group B type 3 infection upregulates expression of monocyte chemoattractant protein 1 in cardiac myocytes, which leads to enhanced migration of mononuclear cells in viral myocarditis. J Virol 2004; 78:12548-56. [PMID: 15507642 PMCID: PMC525049 DOI: 10.1128/jvi.78.22.12548-12556.2004] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Coxsackievirus group B type 3 (CVB3) is an important cause of viral myocarditis. The infiltration of mononuclear cells into the myocardial tissue is one of the key events in viral myocarditis. Immediately after CVB3 infects the heart, the expression of chemokine(s) by infected myocardial cells may be the first trigger for inflammatory infiltration and immune response. However, it is unknown whether CVB3 can induce the chemokine expression in cardiac myocytes. Monocyte chemoattractant protein 1 (MCP-1) is a potent chemokine that stimulates the migration of mononuclear cells. The objective of the present study was to investigate the effect of CVB3 infection on MCP-1 expression in murine cardiac myocytes and the role of MCP-1 in migration of mononuclear cells in viral myocarditis. Our results showed that the expression of MCP-1 was significantly increased in cardiac myocytes after wild-type CVB3 infection in a time- and dose-dependent manner, which resulted in enhanced migration of mononuclear cells in mice with viral myocarditis. The migration of mononuclear cells was partially abolished by antibodies specific for MCP-1 in vivo and in vitro. Administration of anti-MCP-1 antibody prevented infiltration of mononuclear cells bearing the MCP-1 receptor CCR2 in mice with viral myocarditis. Infection by UV-irradiated CVB3 induced rapid and transient expression of MCP-1 in cardiac myocytes. In conclusion, our results indicate that CVB3 infection stimulates the expression of MCP-1 in myocardial cells, which subsequently leads to migration of mononuclear cells in viral myocarditis.
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Affiliation(s)
- Yan Shen
- Department of Immunology, Shanghai Medical College of Fudan University, 138 YiXueYuan Rd., Shanghai 200032, People's Republic of China
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Meyer RG, Meyer-Ficca ML, Kaiser H, Selinka HC, Kandolf R, Küpper JH. Plasmid-based generation of recombinant coxsackievirus B3 particles carrying capsid gene replacement replicons. Virus Res 2004; 104:17-26. [PMID: 15177888 DOI: 10.1016/j.virusres.2004.02.037] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2003] [Revised: 02/18/2004] [Accepted: 02/18/2004] [Indexed: 11/24/2022]
Abstract
Recombinant infectious coxsackievirus B3 (CVB3) particles were generated by packaging of modified viral genomes in which the capsid coding P1-region was replaced by an EGFP-luciferase reporter gene. Efficient packaging of the recombinant genome was achieved by a novel method based on cotransfection of a plasmid encoding the subgenomic viral replicon together with two alternative helper plasmids carrying expression cassettes of the CVB3 capsid proteins, and a T7 RNA polymerase expression plasmid. Transcription of a reporter gene and expression of capsid proteins were achieved in a single step, eliminating the need of a helper virus. Recombinant viral stocks were used to infect human embryonal cardiomyocytes (hCMC) and other cell types, and luciferase activity was measured at different timepoints after infection. Neither progeny virus nor wildtype CVB3 was produced upon infection of target cells, facilitating analyses of infected cells without viral spread. The presence of an IRES sequence upstream of the P1 open reading frame in the helper plasmids was indispensable for the generation of recombinant particles, as no packaging was observed using helper plasmids without this feature. Luciferase data obtained by transfection of reporter plasmids with and without upstream 5'-NTR sequences suggests that the CVB3 IRES facilitates translation in T7 RNA polymerase-dependent gene transcription, both in presence and absence of viral replication.
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Affiliation(s)
- Ralph G Meyer
- Department of Molecular Pathology, University Hospital of Tübingen, Liebermeisterstr. 8, D-72076 Tübingen, Germany.
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37
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Esfandiarei M, Luo H, Yanagawa B, Suarez A, Dabiri D, Zhang J, McManus BM. Protein kinase B/Akt regulates coxsackievirus B3 replication through a mechanism which is not caspase dependent. J Virol 2004; 78:4289-98. [PMID: 15047842 PMCID: PMC374262 DOI: 10.1128/jvi.78.8.4289-4298.2004] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The role of signaling pathways including the mitogen-activated protein kinases (MAPKs) and phosphatidylinositol 3-kinase (PI3K) during viral infection has gained much recent attention. Our laboratory reported on an important regulatory role for extracellular signal-regulated kinases (ERK1/2), subfamily members of the MAPKs, during coxsackievirus B3 (CVB3) infection. However, the role of the PI3K pathway in CVB3 infection has not been well characterized. CVB3 is the most common known viral infectant of heart muscle that directly injures and kills infected cardiac myocytes during the myocarditic process. In the present study, we investigated the role of protein kinase B (PKB) (also known as Akt), a general downstream mediator of survival signals through the PI3K cascade, in regulating CVB3 replication and virus-induced apoptosis in a well-established HeLa cell model. We have demonstrated that CVB3 infection leads to phosphorylation of PKB/Akt on both Ser-473 and Thr-308 residues through a PI3K-dependent mechanism. Transfection of HeLa cells with a dominant negative mutant of Akt1 or pretreatment of wild-type HeLa cells with the specific PI3K inhibitor LY294002 significantly suppresses viral RNA expression, as reflected in diminished viral capsid protein expression and viral release. Dominant negative Akt1 and LY294002 also increase apoptosis in infected cells, which can be reversed by addition of the general caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (zVAD.fmk). Interestingly, blocking of apoptosis by zVAD.fmk does not reverse the viral RNA translation blockade, indicating that the inhibitory effect of dominant negative Akt1 on viral protein expression is not caspase dependent. In addition, we showed that the attachment of virus to its receptor-coreceptor complex is not sufficient for PKB/Akt activation and that postentry viral replication is required for Akt phosphorylation. Taken together, these data illustrate a new and imperative role for Akt in CVB3 infection in HeLa cells and show that the PI3K/Akt signaling is beneficial to CVB3 replication.
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Affiliation(s)
- Mitra Esfandiarei
- The James Hogg iCAPTURE Centre for Cardiovascular and Pulmonary Research, Department of Pathology and Laboratory Medicine, St. Paul's Hospital/Providence Health Care-University of British Columbia, Vancouver, Canada
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Feuer R, Mena I, Pagarigan RR, Hassett DE, Whitton JL. Coxsackievirus replication and the cell cycle: a potential regulatory mechanism for viral persistence/latency. Med Microbiol Immunol 2004; 193:83-90. [PMID: 12925877 DOI: 10.1007/s00430-003-0192-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2003] [Indexed: 11/26/2022]
Abstract
Coxsackieviruses (CV) are characterized by their ability to cause cytopathic effects in tissue culture and by their capacity to initiate acute disease by inducing apoptosis within targeted organs in vivo. These viruses are considered highly cytolytic, but can establish persistence/latency in susceptible cells, indicating that a regulatory mechanism may exist to shut off viral protein synthesis and replication under certain situations. The persistence of coxsackieviral RNA is of particular medical interest due to its association with chronic human diseases such as dilated cardiomyopathy and chronic inflammatory myopathy. Here, we discuss the potential mechanisms regulating coxsackievirus replication, and the ability of viral RNA to remain in an apparent latent state within quiescent cells.
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Affiliation(s)
- Ralph Feuer
- Department of Neuropharmacology, CVN-9, The Scripps Research Institute, 10550 N. Torrey Pines Rd., La Jolla, CA 92037, USA
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Selinka HC, Wolde A, Sauter M, Kandolf R, Klingel K. Virus-receptor interactions of coxsackie B viruses and their putative influence on cardiotropism. Med Microbiol Immunol 2004; 193:127-31. [PMID: 12920584 DOI: 10.1007/s00430-003-0193-y] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2003] [Indexed: 10/26/2022]
Abstract
Specific virus-receptor interactions are important determinants in the pathogenesis of viral infections, influencing the location and initiation of primary infection as well as the viral spread to other target organs in the postviremic phase. Coxsackieviruses of group B (CVB) specifically interact with at least two receptor proteins, the coxsackievirus-adenovirus receptor (CAR) and the decay-accelerating factor (DAF), and cause a broad spectrum of diseases, including acute and chronic myocarditis. In the human heart, CAR is predominantly expressed in intercalated discs, regions of utmost importance for the functional integrity of the heart. Since DAF is abundantly expressed in epithelial and endothelial cells, interaction of cardiotropic CVB with the DAF coreceptor protein, in addition to CAR, could therefore be advantageous to the virus by enhancing viral entry into the heart.
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Affiliation(s)
- Hans-Christoph Selinka
- Institut für Medizinische Mikrobiologie und Hygiene, Johannes-Gutenberg-Universität Mainz, Hochhaus am Augustusplatz, 55101 Mainz, Germany.
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Zhang H, Li Y, McClean DR, Richardson PJ, Florio R, Sheppard M, Morrison K, Latif N, Dunn MJ, Archard LC. Detection of enterovirus capsid protein VP1 in myocardium from cases of myocarditis or dilated cardiomyopathy by immunohistochemistry: further evidence of enterovirus persistence in myocytes. Med Microbiol Immunol 2003; 193:109-14. [PMID: 14634804 DOI: 10.1007/s00430-003-0208-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2003] [Indexed: 11/26/2022]
Abstract
The association of enteroviruses with myocardial disease has been investigated extensively by molecular biological techniques to detect viral RNA, but remains controversial. This retrospective study investigated the involvement of enterovirus in myocarditis or dilated cardiomyopathy (DCM) by detection of viral antigens in myocardial samples from a new patient series using an optimized immunohistochemical technique. Formalin-fixed, paraffin-embedded biopsy, autopsy or explanted myocardial tissue samples were obtained from 136 subjects. These comprised histologically proven cases of acute fatal myocarditis (n=10), DCM (n=89, including 10 patients with healing/borderline myocarditis) and a comparison group of samples from 37 unused donor hearts and cases with other conditions. A monoclonal antibody 5-D8/1 directed against a conserved, non-conformational epitope in capsid protein VP1 was employed for broad detection of different enterovirus serotypes. Investigations were performed blindly. Histological sections from 7 of 10 fatal myocarditis cases, 47 of 89 patients (52.8%) with DCM were positive for the viral capsid protein VP1 by immunohistochemical staining. Consecutive sections of positive samples were negative when the antibody was omitted or replaced with subclass- and concentration-matched normal mouse IgG. In contrast, only 3 of 37 samples (8.1%) in the comparison group were positive (Yates corrected chi(2)=19.99, P<0.001: odds ratio =12.68). VP1 staining was distributed in individual or grouped myofibers and localized in the cytoplasm of myocytes. In some cases, VP1 was detected in only a few myofibers within an entire section. These results provide further evidence of enterovirus involvement in a high proportion of DCM cases and demonstrate that VP1 is present in disease stages from acute myocarditis, healing myocarditis to end-stage DCM requiring cardiac transplantation, indicating translation of viral protein during persistent enterovirus infection.
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Affiliation(s)
- Hongyi Zhang
- Cell and Molecular Biology Section, Division of Biomedical Sciences, Faculty of Medicine, Imperial College, London, UK.
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Hirasawa K, Kim A, Han HS, Han J, Jun HS, Yoon JW. Effect of p38 mitogen-activated protein kinase on the replication of encephalomyocarditis virus. J Virol 2003; 77:5649-56. [PMID: 12719557 PMCID: PMC154047 DOI: 10.1128/jvi.77.10.5649-5656.2003] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cellular phosphorylation events during viral infection are necessary for effective viral replication. Encephalomyocarditis (EMC) virus has been used for studies on the molecular mechanisms of viral replication, but little is known about the cellular signaling pathways involved. This investigation was initiated to determine whether mitogen-activated protein kinases (MAPKs), which are central components of signal transduction pathways in the regulation of cell proliferation, play a role in the replication of EMC virus. We examined the phosphorylation of MAPKs, including extracellular signal-regulated kinase (ERK1/2), p38 MAPK, and stress-activated protein kinase 1/c-Jun NH(2)-terminal kinase (SAPK/JNK) in EMC virus-infected L929 cells and found that p38 MAPK and SAPK-JNK, but not ERK1/2, were activated during viral infection. We then examined the effect of these kinases on the replication of EMC virus in L929 cells by using specific inhibitors, including genistein or herbimycin A for tyrosine kinase, SB203580 or SB202190 for p38 MAPK, and PD98059 for ERK1/2. We found that the tyrosine kinase and p38 MAPK inhibitors, but not the ERK1/2 inhibitor, suppressed viral replication and that the inhibitory effect was primarily on viral protein synthesis. Finally, we examined whether p38 MAPK is involved in the translation of EMC viral transcripts by using L929 cells transfected with a gene construct containing the internal ribosomal entry site (IRES) of EMC virus and a luciferase reporter gene. We found that the p38 MAPK inhibitor suppressed the translation of EMC viral RNA. On the basis of these observations, we conclude that p38 MAPK plays a critical role in the replication of EMC virus, probably in the translation of viral RNA.
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Affiliation(s)
- Kensuke Hirasawa
- Laboratory of Viral Immunopathogenesis of Diabetes, Julia McFarlane Diabetes Research Centre, Department of Microbiology and Infectious Diseases, Faculty of Medicine, The University of Calgary, Calgary, Alberta T2N 4N1, Canada
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Cunningham KA, Chapman NM, Carson SD. Caspase-3 activation and ERK phosphorylation during CVB3 infection of cells: influence of the coxsackievirus and adenovirus receptor and engineered variants. Virus Res 2003; 92:179-86. [PMID: 12686427 DOI: 10.1016/s0168-1702(03)00044-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Caspase activation and MAP kinase signaling have been implicated in coxsackievirus B3 (CVB3) pathogenesis, and both have been demonstrated late in the virus life cycle. We studied activation of caspase-3, an effector protease of apoptosis, and ERK phosphorylation, indicative of MAPK signaling pathway activation, following CVB3 infection of cells that express the coxsackievirus and adenovirus receptor (CAR) or CAR constructs lacking the cytoplasmic domain, and cells which express no detectable CAR. These experiments showed that a burst of caspase-3 activity preceded lysis of CVB3-infected cells expressing CAR, irrespective of the CAR cytoplasmic domain. In RD cells, which were infected in the absence of detectable CAR, caspase-3 activity increased progressively over 52 h with no apparent burst. ERK phosphorylation also occurred late in the virus life cycle, preceding caspase-3 activation, and occurred in cells expressing full-length CAR but not in RD. These results show that ERK phosphorylation precedes caspase-3 activation, both occur late in the infection, and both are influenced by the presence of CAR.
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Affiliation(s)
- Kelly A Cunningham
- The Picornaviral Research Unit, Discipline of Immunology and Microbiology, Faculty of Medicine and Health Sciences, The University of Newcastle, Newcastle, New South Wales 2300, Australia
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Opavsky MA, Martino T, Rabinovitch M, Penninger J, Richardson C, Petric M, Trinidad C, Butcher L, Chan J, Liu PP. Enhanced ERK-1/2 activation in mice susceptible to coxsackievirus-induced myocarditis. J Clin Invest 2002; 109:1561-9. [PMID: 12070303 PMCID: PMC151008 DOI: 10.1172/jci13971] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Group B coxsackieviral (CVB) infection commonly causes viral myocarditis. Mice are protected from CVB3 myocarditis by gene-targeted knockout of p56(Lck)(Lck), the Src family kinase (Src) essential for T cell activation. Extracellular signal-regulated kinase 1 and 2 (ERK-1/2) can influence cell function downstream of Lck. Using T cell lines and neonatal cardiac myocytes we investigated the role of ERK-1/2 in CVB3 infection. In Jurkat T cells ERK-1/2 is rapidly activated by CVB3; but, this response is absent in Lck-negative JCaM T cells. Inhibition of ERK-1/2 with UO126 reduced CVB3 titers in Jurkat cells, but not in JCaM cells. In cardiac myocytes CVB3 activation of ERK-1/2 is blocked by the Src inhibitor PP2. In addition, viral production in myocytes is decreased by Src or ERK-1/2 inhibition. In vitro, in both immune and myocardial cells, ERK-1/2 is activated by CVB3 downstream of Lck and other Src's and is necessary for efficient CVB3 replication. In vivo, following CVB3 infection, ERK-1/2 activation is evident in the myocardium. ERK-1/2 activation is intense in the hearts of myocarditis-susceptible A/J mice. In contrast, significantly less ERK-1/2 activation is found in the hearts of myocarditis-resistant C57BL/6 mice. Therefore, the ERK-1/2 response to CVB3 infection may contribute to differential host susceptibility to viral myocarditis.
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Affiliation(s)
- Mary Anne Opavsky
- The Heart and Stroke/Richard Lewar Centre of Excellence, The University of Toronto, Toronto, Ontario, Canada.
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Opavsky MA, Martino T, Rabinovitch M, Penninger J, Richardson C, Petric M, Trinidad C, Butcher L, Chan J, Liu PP. Enhanced ERK-1/2 activation in mice susceptible to coxsackievirus-induced myocarditis. J Clin Invest 2002. [DOI: 10.1172/jci0213971] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Feuer R, Mena I, Pagarigan R, Slifka MK, Whitton JL. Cell cycle status affects coxsackievirus replication, persistence, and reactivation in vitro. J Virol 2002; 76:4430-40. [PMID: 11932410 PMCID: PMC155066 DOI: 10.1128/jvi.76.9.4430-4440.2002] [Citation(s) in RCA: 140] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Enteroviral persistence has been implicated in the pathogenesis of several chronic human diseases, including dilated cardiomyopathy, insulin-dependent diabetes mellitus, and chronic inflammatory myopathy. However, these viruses are considered highly cytolytic, and it is unclear what mechanisms might permit their long-term survival. Here, we describe the generation of a recombinant coxsackievirus B3 (CVB3) expressing the enhanced green fluorescent protein (eGFP), which we used to mark and track infected cells in vitro. Following exposure of quiescent tissue culture cells to either wild-type CVB3 or eGFP-CVB3, virus production was very limited but increased dramatically after cells were permitted to divide. Studies with cell cycle inhibitors revealed that cells arrested at the G(1) or G(1)/S phase could express high levels of viral polyprotein and produced abundant infectious virus. In contrast, both protein expression and virus yield were markedly reduced in quiescent cells (i.e., cells in G(0)) and in cells blocked at the G(2)/M phase. Following infection with eGFP-CVB3, quiescent cells retained viral RNA for several days in the absence of infectious virus production. Furthermore, RNA extracted from nonproductive quiescent cells was infectious when transfected into dividing cells, indicating that CVB3 appears to be capable of establishing a latent infection in G(0) cells, at least in tissue culture. Finally, wounding of infected quiescent cells resulted in viral protein expression limited to cells in and adjacent to the lesion. We suggest that (i) cell cycle status determines the distribution of CVB3 during acute infection and (ii) the persistence of CVB3 in vivo may rely on infection of quiescent (G(0)) cells incapable of supporting viral replication; a subsequent change in the cell cycle status may lead to virus reactivation, triggering chronic viral and/or immune-mediated pathology in the host.
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Affiliation(s)
- Ralph Feuer
- Department of Neuropharmacology, The Scripps Research Institute, La Jolla, California 92037, USA
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Luo H, Yanagawa B, Zhang J, Luo Z, Zhang M, Esfandiarei M, Carthy C, Wilson JE, Yang D, McManus BM. Coxsackievirus B3 replication is reduced by inhibition of the extracellular signal-regulated kinase (ERK) signaling pathway. J Virol 2002; 76:3365-73. [PMID: 11884562 PMCID: PMC136021 DOI: 10.1128/jvi.76.7.3365-3373.2002] [Citation(s) in RCA: 168] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Coxsackievirus B3 (CVB3) is the most common human pathogen for viral myocarditis. We have previously shown that the signaling protein p21(ras) GTPase-activating protein (RasGAP) is cleaved and that mitogen-activated protein kinases (MAPKs) ERK1/2 are activated in the late phase of CVB3 infection. However, the role of intracellular signaling pathways in CVB3-mediated myocarditis and the relative advantages of such pathways to host or virus remain largely unclear. In this study we extended our prior studies by examining the interaction between CVB3 replication and intracellular signaling pathways in HeLa cells. We observed that CVB3 infection induced a biphasic activation of ERK1/2, early transient activation versus late sustained activation, which were regulated by different mechanisms. Infection by UV-irradiated, inactivated virus capable of receptor binding and endocytosis triggered early ERK1/2 activation, but was insufficient to trigger late ERK1/2 activation. By using a general caspase inhibitor (zVAD.fmk) we further demonstrated that late ERK1/2 activation was not a result of CVB3-mediated caspase cleavage. Treatment of cells with U0126, a selective inhibitor of MAPK kinase (MEK), significantly inhibited CVB3 progeny release and decreased virus protein production. Furthermore, inhibition of ERK1/2 activation circumvented CVB3-induced apoptosis and viral protease-mediated RasGAP cleavage. Taken together, these data suggest that ERK1/2 activation is important for CVB3 replication and contributes to virus-mediated changes in host cells. Our findings demonstrate coxsackievirus takeover of a particular host signaling mechanism and uncover a prospective approach to stymie virus spread and preserve myocardial integrity.
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Affiliation(s)
- Honglin Luo
- Department of Pathology and Laboratory Medicine, McDonald Research Laboratories/The iCAPTURE Center, St. Paul's Hospital/Providence Health Care-University of British Columbia, Vancouver, British Columbia, Canada
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Fujioka S, Kitaura Y. Coxsackie B virus infection in idiopathic dilated cardiomyopathy: clinical and pharmacological implications. BioDrugs 2002; 15:791-9. [PMID: 11784211 DOI: 10.2165/00063030-200115120-00002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Idiopathic dilated cardiomyopathy (IDC) is a myocardial disease characterised by ventricular dilatation, impaired contractility, and the symptoms of congestive heart failure. Although the causes of IDC remain uncertain, much interest has been focused on the enteroviral infection in the myocardium in the pathogenesis of this disease. Enteroviral RNA has been demonstrated in the myocardium at all stages of IDC. Recent studies using sequence analysis of enteroviral polymerase chain reaction (PCR) products have shown that the viruses detected in hearts of patients with IDC are coxsackie B. In addition, active coxsackieviral RNA replication in the myocardium has been demonstrated by strand-specific detection of viral RNA. Viral antigen has also been found in hearts with IDC by immunohistochemical techniques. In tissue culture experiments and transgenic mice, it has been shown that restricted coxsackieviral RNA replication, and not infectious virus progeny, in the myocardium can impair cardiac contractile function and lead to dilated cardiomyopathy. Coxsackieviral RNA in the myocardium can be a marker of a poor clinical outcome after partial left ventriculectomy, and might influence prognosis after heart transplantation. Therefore, there is a therapeutic need to detect replicating coxsackieviral RNA in the myocardium, and a specific therapy for coxsackie B viruses is indicated in the management of patients with virus-positive IDC.
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Affiliation(s)
- S Fujioka
- Third Division, Department of Internal Medicine, Osaka Medical College, Takatsuki, Osaka, Japan
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Barber SA, Bruett L, Douglass BR, Herbst DS, Zink MC, Clements JE. Visna virus-induced activation of MAPK is required for virus replication and correlates with virus-induced neuropathology. J Virol 2002; 76:817-28. [PMID: 11752171 PMCID: PMC136850 DOI: 10.1128/jvi.76.2.817-828.2002] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
It is well accepted that viruses require access to specific intracellular environments in order to proliferate or, minimally, to secure future proliferative potential as latent reservoirs. Hence, identification of essential virus-cell interactions should both refine current models of virus replication and proffer alternative targets for therapeutic intervention. In the present study, we examined the activation states of mitogen-activated protein kinases (MAPKs), ERK-1/2, in primary cells susceptible to visna virus and report that virus infection induces and sustains activation of the ERK/MAPK pathway. Treatment of infected cells with PD98059, a specific inhibitor of the ERK/MAPK pathway, abolishes visna virus replication, as evidenced by extremely low levels of Gag protein expression and reverse transcriptase activity in culture supernatants. In addition, although visna virus-induced activation of MAPK is detectable within 15 min, early events of viral replication (i.e., reverse transcription, integration, and transcription) are largely unaffected by PD98059. Interestingly, further examination demonstrated that treatment with PD98059 results in decreased cytoplasmic expression of gag and env, but not rev, mRNA, highly suggestive of an ERK/MAPK-dependent defect in Rev function. In vivo analysis of ERK-1/2 activation in brains derived from visna virus-infected sheep demonstrates a strong correlation between ERK/MAPK activation and virus-associated encephalitis. Moreover, double-labeling experiments revealed that activation of MAPK occurs not only in cells classically infected by visna virus (i.e., macrophages and microglia), but also in astrocytes, cells not considered to be major targets of visna virus replication, suggesting that activation of the ERK/MAPK pathway may contribute to the virus-induced processes leading to neurodegenerative pathology.
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MESH Headings
- Animals
- Astrocytes/enzymology
- Astrocytes/virology
- Brain/enzymology
- Brain/pathology
- Brain/virology
- Butadienes/pharmacology
- Cells, Cultured
- Encephalitis, Viral/enzymology
- Encephalitis, Viral/pathology
- Encephalitis, Viral/virology
- Enzyme Activation/drug effects
- Enzyme Inhibitors/pharmacology
- Flavonoids/pharmacology
- Gene Products, env/biosynthesis
- Gene Products, env/genetics
- Gene Products, gag/biosynthesis
- Gene Products, gag/genetics
- Gene Products, rev/biosynthesis
- Gene Products, rev/genetics
- Goats/virology
- Immunohistochemistry
- MAP Kinase Kinase 1
- MAP Kinase Signaling System/drug effects
- Macrophages/enzymology
- Macrophages/virology
- Mitogen-Activated Protein Kinase Kinases/antagonists & inhibitors
- Mitogen-Activated Protein Kinase Kinases/metabolism
- Mitogen-Activated Protein Kinases/metabolism
- Nitriles/pharmacology
- Protein Serine-Threonine Kinases/antagonists & inhibitors
- Protein Serine-Threonine Kinases/metabolism
- RNA, Viral/genetics
- RNA, Viral/metabolism
- Sheep/virology
- Virulence
- Virus Replication/drug effects
- Visna-maedi virus/drug effects
- Visna-maedi virus/genetics
- Visna-maedi virus/pathogenicity
- Visna-maedi virus/physiology
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Affiliation(s)
- Sheila A Barber
- Division of Comparative Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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Payne E, Bowles MR, Don A, Hancock JF, McMillan NA. Human papillomavirus type 6b virus-like particles are able to activate the Ras-MAP kinase pathway and induce cell proliferation. J Virol 2001; 75:4150-7. [PMID: 11287564 PMCID: PMC114160 DOI: 10.1128/jvi.75.9.4150-4157.2001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The initial step in viral infection is the attachment of the virus to the host cell via an interaction with its receptor. We have previously shown that a receptor for human papillomavirus is the alpha6 integrin. The alpha6 integrin is involved in the attachment of epithelial cells with the basement membrane, but recent evidence suggests that ligation of many integrins results in intracellular signaling events that influence cell proliferation. Here we present evidence that exposure of A431 human epithelial cells to human papillomavirus type 6b L1 virus-like particles (VLPs) results in a dose-dependent increase in cell proliferation, as measured by bromodeoxyuridine incorporation. This proliferation is lost if VLPs are first denatured or incubated with a monoclonal antibody against L1 protein. The MEK1 inhibitor PB98059 inhibits the VLP-mediated increase in cell proliferation, suggesting involvement of the Ras-MAP kinase pathway. Indeed, VLP binding results in rapid phosphorylation of the beta4 integrin upon tyrosine residues and subsequent recruitment of the adapter protein Shc to beta4. Within 30 min, the activation of Ras, Raf, and Erk2 was observed. Finally, the upregulation of c-myc mRNA was observed at 60 min. These data indicate that human papillomavirus type 6b is able to signal cells via the Ras-MAP kinase pathway to induce cell proliferation. We hypothesize that such a mechanism would allow papillomaviruses to infect hosts more successfully by increasing the potential pool of cells they are able to infect via the initiation of proliferation in resting keratinocyte stem and suprabasal cells.
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Affiliation(s)
- E Payne
- Molecular Virology Laboratory, Centre for Immunology and Cancer Research, P.A. Hospital, University of Queensland, Brisbane, Australia
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Chen J, Stinski MF. Activation of transcription of the human cytomegalovirus early UL4 promoter by the Ets transcription factor binding element. J Virol 2000; 74:9845-57. [PMID: 11024111 PMCID: PMC102021 DOI: 10.1128/jvi.74.21.9845-9857.2000] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The human cytomegalovirus (HCMV) early UL4 promoter has served as a useful model for studying the activation of early viral gene expression. Previous transient-transfection experiments detected cis-acting elements (the NF-Y site and site 2) upstream of the transcriptional start site (L. Huang and M. F. Stinski, J. Virol. 69:7612-7621, 1995). The roles of two of these sites, the NF-Y site and site 2, in the context of the viral genome were investigated further by comparing mRNA levels from the early UL4 promoter in human foreskin fibroblasts infected by recombinant viruses with either wild-type or mutant cis-acting elements. Steady-state mRNA levels from the UL4 promoter with a mutation in the NF-Y site were comparable to that of wild type. A mutation in an Elk-1 site plus putative IE86 protein binding sites decreased the steady-state mRNA levels compared to the wild type at early times after infection. Electrophoretic mobility shift assays and antibody supershifts detected the binding of cellular transcription factor Elk-1 to site 2 DNA with infected nuclear extracts but not with mock-infected nuclear extracts. The role of cellular transcription factors activated by the mitogen activated protein kinase/extracellular signal-regulated kinase pathway in activating transcription from early viral promoters is discussed.
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Affiliation(s)
- J Chen
- Department of Microbiology, College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA
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