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Mehedi M, Ricklefs S, Takada A, Sturdevant D, Porcella SF, Marzi A, Feldmann H. RNA Editing as a General Trait of Ebolaviruses. J Infect Dis 2023; 228:S498-S507. [PMID: 37348869 PMCID: PMC10651210 DOI: 10.1093/infdis/jiad228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 06/06/2023] [Accepted: 06/20/2023] [Indexed: 06/24/2023] Open
Abstract
RNA editing has been discovered as an essential mechanism for the transcription of the glycoprotein (GP) gene of Ebola virus but not Marburg virus. We developed a rapid transcript quantification assay (RTQA) to analyze RNA transcripts generated through RNA editing and used immunoblotting with a pan-ebolavirus monoclonal antibody to confirm different GP gene-derived products. RTQA successfully quantified GP gene transcripts during infection with representative members of 5 ebolavirus species. Immunoblotting verified expression of the soluble GP and the transmembrane GP. Our results defined RNA editing as a general trait of ebolaviruses. The degree of editing, however, varies among ebolaviruses with Reston virus showing the lowest and Bundibugyo virus the highest degree of editing.
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Affiliation(s)
| | - Stacy Ricklefs
- Genomics Unit, Research Technology Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana
| | - Ayato Takada
- Division of Global Epidemiology, International Institute for Zoonosis Control, Hokkaido University, Sapporo, Japan
| | - Dan Sturdevant
- Genomics Unit, Research Technology Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana
| | - Stephen F Porcella
- Genomics Unit, Research Technology Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana
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2
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Sekrecka A, Kluzek K, Sekrecki M, Boroujeni ME, Hassani S, Yamauchi S, Sada K, Wesoly J, Bluyssen HAR. Time-dependent recruitment of GAF, ISGF3 and IRF1 complexes shapes IFNα and IFNγ-activated transcriptional responses and explains mechanistic and functional overlap. Cell Mol Life Sci 2023; 80:187. [PMID: 37347298 DOI: 10.1007/s00018-023-04830-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 05/09/2023] [Accepted: 06/08/2023] [Indexed: 06/23/2023]
Abstract
To understand in detail the transcriptional and functional overlap of IFN-I- and IFN-II-activated responses, we used an integrative RNAseq-ChIPseq approach in Huh7.5 cells and characterized the genome-wide role of pSTAT1, pSTAT2, IRF9 and IRF1 in time-dependent ISG expression. For the first time, our results provide detailed insight in the timely steps of IFNα- and IFNγ-induced transcription, in which pSTAT1- and pSTAT2-containing ISGF3 and GAF-like complexes and IRF1 are recruited to individual or combined ISRE and GAS composite sites in a phosphorylation- and time-dependent manner. Interestingly, composite genes displayed a more heterogeneous expression pattern, as compared to GAS (early) and ISRE genes (late), with the time- and phosphorylation-dependent recruitment of GAF, ISGF3 and IRF1 after IFNα stimulation and GAF and IRF1 after IFNγ. Moreover, functional composite genes shared features of GAS and ISRE genes through transcription factor co-binding to closely located sites, and were able to sustain IFN responsiveness in STAT1-, STAT2-, IRF9-, IRF1- and IRF9/IRF1-mutant Huh7.5 cells compared to Wt cells. Thus, the ISRE + GAS composite site acted as a molecular switch, depending on the timely available components and transcription factor complexes. Consequently, STAT1, STAT2 and IRF9 were identified as functional composite genes that are part of a positive feedback loop controlling long-term IFNα and IFNγ responses. More important, in the absence of any one of the components, the positive feedback regulation of the ISGF3 and GAF components appeared to be preserved. Together, these findings provide further insight in the existence of a novel ISRE + GAS composite-dependent intracellular amplifier circuit prolonging ISG expression and controlling cellular responsiveness to different types of IFNs and subsequent antiviral activity. It also offers an explanation for the existing molecular and functional overlap between IFN-I- and IFN-II-activated ISG expression.
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Affiliation(s)
- Agata Sekrecka
- Human Molecular Genetics Research Unit, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Poznan, Poland
| | - Katarzyna Kluzek
- Human Molecular Genetics Research Unit, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Poznan, Poland
| | - Michal Sekrecki
- Human Molecular Genetics Research Unit, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Poznan, Poland
| | - Mahdi Eskandarian Boroujeni
- Human Molecular Genetics Research Unit, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Poznan, Poland
| | - Sanaz Hassani
- Human Molecular Genetics Research Unit, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Poznan, Poland
| | - Shota Yamauchi
- Department of Genome Science and Microbiology, Faculty of Medical Sciences, University of Fukui, Fukui, Japan
| | - Kiyonao Sada
- Department of Genome Science and Microbiology, Faculty of Medical Sciences, University of Fukui, Fukui, Japan
| | - Joanna Wesoly
- High Throughput Technologies Laboratory, Faculty of Biology, Adam Mickiewicz University, Poznan, Poland
| | - Hans A R Bluyssen
- Human Molecular Genetics Research Unit, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Poznan, Poland.
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3
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Riera E, García-Belmonte R, Madrid R, Pérez-Núñez D, Revilla Y. African swine fever virus ubiquitin-conjugating enzyme pI215L inhibits IFN-I signaling pathway through STAT2 degradation. Front Microbiol 2023; 13:1081035. [PMID: 36713190 PMCID: PMC9880986 DOI: 10.3389/fmicb.2022.1081035] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 12/20/2022] [Indexed: 01/15/2023] Open
Abstract
African swine fever virus (ASFV) is the causative agent of one of the most lethal diseases affecting domestic pig and wild boar, which is endangering the swine industry due to its rapid expansion. ASFV has developed different mechanisms to evade the host immune response, including inhibition of type I IFN (IFN-I) production and signaling, since IFN-I is a key element in the cellular antiviral response. Here, we report a novel mechanism of evasion of the IFN-I signaling pathway carried out by the ASFV ubiquitin-conjugating enzyme pI215L. Our data showed that pI215L inhibited IFN-stimulated response element (ISRE) activity and the consecutive mRNA induction of the IFN-stimulated genes ISG15 and IFIT1 through the ubiquitination and proteasomal degradation of STAT2. Additionally, by immunofluorescence, co-immunoprecipitation and nucleus-cytoplasm fractionation approaches, we have confirmed the interaction and colocalization of STAT2 and pI215L, in ectopic experiments and during ASFV infection. Moreover, expression of the catalytic mutant (I215L-C85A) did not inhibit the induction of ISG15 and IFIT1, nor the activity of ISRE. Furthermore, we confirmed that STAT2 degradation by pI215L is dependent on its catalytic activity, since expression of the pI215L-C85A mutant did not affect STAT2 levels, compared to the wild-type protein. Yet, our data reveal that the interaction of pI215L with STAT2 does not require the integrity of its catalytic domain since the pI215L-C85A mutant co-immunoprecipitates with STAT2. All these findings reveal, for the first time, the involvement of E2-ubiquitin-conjugating enzyme activity of pI215L in the immune response modulation.
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Affiliation(s)
- Elena Riera
- Microbes in Health and Welfare Department, Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain
| | - Raquel García-Belmonte
- Microbes in Health and Welfare Department, Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain
| | - Ricardo Madrid
- Bioassays SL, UAM, Madrid, Spain,Department of Genetics, Physiology and Microbiology, Faculty of Biological Sciences, Biology, UCM, Madrid, Spain
| | - Daniel Pérez-Núñez
- Microbes in Health and Welfare Department, Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain
| | - Yolanda Revilla
- Microbes in Health and Welfare Department, Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain,*Correspondence: Yolanda Revilla, ✉
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Type I and Type II Interferon Antagonism Strategies Used by Paramyxoviridae: Previous and New Discoveries, in Comparison. Viruses 2022; 14:v14051107. [PMID: 35632848 PMCID: PMC9145045 DOI: 10.3390/v14051107] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 05/15/2022] [Accepted: 05/18/2022] [Indexed: 02/04/2023] Open
Abstract
Paramyxoviridae is a viral family within the order of Mononegavirales; they are negative single-strand RNA viruses that can cause significant diseases in both humans and animals. In order to replicate, paramyxoviruses–as any other viruses–have to bypass an important protective mechanism developed by the host’s cells: the defensive line driven by interferon. Once the viruses are recognized, the cells start the production of type I and type III interferons, which leads to the activation of hundreds of genes, many of which encode proteins with the specific function to reduce viral replication. Type II interferon is produced by active immune cells through a different signaling pathway, and activates a diverse range of genes with the same objective to block viral replication. As a result of this selective pressure, viruses have evolved different strategies to avoid the defensive function of interferons. The strategies employed by the different viral species to fight the interferon system include a number of sophisticated mechanisms. Here we analyzed the current status of the various strategies used by paramyxoviruses to subvert type I, II, and III interferon responses.
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Siering O, Cattaneo R, Pfaller CK. C Proteins: Controllers of Orderly Paramyxovirus Replication and of the Innate Immune Response. Viruses 2022; 14:v14010137. [PMID: 35062341 PMCID: PMC8778822 DOI: 10.3390/v14010137] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 01/07/2022] [Accepted: 01/09/2022] [Indexed: 01/07/2023] Open
Abstract
Particles of many paramyxoviruses include small amounts of proteins with a molecular weight of about 20 kDa. These proteins, termed “C”, are basic, have low amino acid homology and some secondary structure conservation. C proteins are encoded in alternative reading frames of the phosphoprotein gene. Some viruses express nested sets of C proteins that exert their functions in different locations: In the nucleus, they interfere with cellular transcription factors that elicit innate immune responses; in the cytoplasm, they associate with viral ribonucleocapsids and control polymerase processivity and orderly replication, thereby minimizing the activation of innate immunity. In addition, certain C proteins can directly bind to, and interfere with the function of, several cytoplasmic proteins required for interferon induction, interferon signaling and inflammation. Some C proteins are also required for efficient virus particle assembly and budding. C-deficient viruses can be grown in certain transformed cell lines but are not pathogenic in natural hosts. C proteins affect the same host functions as other phosphoprotein gene-encoded proteins named V but use different strategies for this purpose. Multiple independent systems to counteract host defenses may ensure efficient immune evasion and facilitate virus adaptation to new hosts and tissue environments.
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Affiliation(s)
- Oliver Siering
- Division of Veterinary Medicine, Paul-Ehrlich-Institute, 63225 Langen, Germany;
| | - Roberto Cattaneo
- Department of Molecular Medicine, Mayo Clinic, Rochester, MN 55906, USA
- Correspondence: (R.C.); (C.K.P.)
| | - Christian K. Pfaller
- Division of Veterinary Medicine, Paul-Ehrlich-Institute, 63225 Langen, Germany;
- Correspondence: (R.C.); (C.K.P.)
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Barik S. Mechanisms of Viral Degradation of Cellular Signal Transducer and Activator of Transcription 2. Int J Mol Sci 2022; 23:ijms23010489. [PMID: 35008916 PMCID: PMC8745392 DOI: 10.3390/ijms23010489] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 12/28/2021] [Accepted: 12/31/2021] [Indexed: 12/31/2022] Open
Abstract
Virus infection of eukaryotes triggers cellular innate immune response, a major arm of which is the type I interferon (IFN) family of cytokines. Binding of IFN to cell surface receptors triggers a signaling cascade in which the signal transducer and activator of transcription 2 (STAT2) plays a key role, ultimately leading to an antiviral state of the cell. In retaliation, many viruses counteract the immune response, often by the destruction and/or inactivation of STAT2, promoted by specific viral proteins that do not possess protease activities of their own. This review offers a summary of viral mechanisms of STAT2 subversion with emphasis on degradation. Some viruses also destroy STAT1, another major member of the STAT family, but most viruses are selective in targeting either STAT2 or STAT1. Interestingly, degradation of STAT2 by a few viruses requires the presence of both STAT proteins. Available evidence suggests a mechanism in which multiple sites and domains of STAT2 are required for engagement and degradation by a multi-subunit degradative complex, comprising viral and cellular proteins, including the ubiquitin–proteasomal system. However, the exact molecular nature of this complex and the alternative degradation mechanisms remain largely unknown, as critically presented here with prospective directions of future study.
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Affiliation(s)
- Sailen Barik
- EonBio, 3780 Pelham Drive, Mobile, AL 36619, USA
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Clementi N, Ghosh S, De Santis M, Castelli M, Criscuolo E, Zanoni I, Clementi M, Mancini N. Viral Respiratory Pathogens and Lung Injury. Clin Microbiol Rev 2021; 34:e00103-20. [PMID: 33789928 PMCID: PMC8142519 DOI: 10.1128/cmr.00103-20] [Citation(s) in RCA: 73] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Several viruses target the human respiratory tract, causing different clinical manifestations spanning from mild upper airway involvement to life-threatening acute respiratory distress syndrome (ARDS). As dramatically evident in the ongoing SARS-CoV-2 pandemic, the clinical picture is not always easily predictable due to the combined effect of direct viral and indirect patient-specific immune-mediated damage. In this review, we discuss the main RNA (orthomyxoviruses, paramyxoviruses, and coronaviruses) and DNA (adenoviruses, herpesviruses, and bocaviruses) viruses with respiratory tropism and their mechanisms of direct and indirect cell damage. We analyze the thin line existing between a protective immune response, capable of limiting viral replication, and an unbalanced, dysregulated immune activation often leading to the most severe complication. Our comprehension of the molecular mechanisms involved is increasing and this should pave the way for the development and clinical use of new tailored immune-based antiviral strategies.
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Affiliation(s)
- Nicola Clementi
- Laboratory of Microbiology and Virology, Vita-Salute San Raffaele University, Milan, Italy
- Laboratory of Microbiology and Virology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Sreya Ghosh
- Harvard Medical School, Boston Children's Hospital, Division of Immunology, Boston, Massachusetts, USA
| | - Maria De Santis
- Department of Rheumatology and Clinical Immunology, Humanitas Clinical and Research Center-IRCCS, Rozzano, Italy
| | - Matteo Castelli
- Laboratory of Microbiology and Virology, Vita-Salute San Raffaele University, Milan, Italy
| | - Elena Criscuolo
- Laboratory of Microbiology and Virology, Vita-Salute San Raffaele University, Milan, Italy
| | - Ivan Zanoni
- Harvard Medical School, Boston Children's Hospital, Division of Immunology, Boston, Massachusetts, USA
- Harvard Medical School, Boston Children's Hospital, Division of Gastroenterology, Boston, Massachusetts, USA
| | - Massimo Clementi
- Laboratory of Microbiology and Virology, Vita-Salute San Raffaele University, Milan, Italy
- Laboratory of Microbiology and Virology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Nicasio Mancini
- Laboratory of Microbiology and Virology, Vita-Salute San Raffaele University, Milan, Italy
- Laboratory of Microbiology and Virology, IRCCS San Raffaele Scientific Institute, Milan, Italy
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8
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Douglas J, Drummond AJ, Kingston RL. Evolutionary history of cotranscriptional editing in the paramyxoviral phosphoprotein gene. Virus Evol 2021; 7:veab028. [PMID: 34141448 PMCID: PMC8204654 DOI: 10.1093/ve/veab028] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The phosphoprotein gene of the paramyxoviruses encodes multiple protein products. The P, V, and W proteins are generated by transcriptional slippage. This process results in the insertion of non-templated guanosine nucleosides into the mRNA at a conserved edit site. The P protein is an essential component of the viral RNA polymerase and is encoded by a faithful copy of the gene in the majority of paramyxoviruses. However, in some cases, the non-essential V protein is encoded by default and guanosines must be inserted into the mRNA in order to encode P. The number of guanosines inserted into the P gene can be described by a probability distribution, which varies between viruses. In this article, we review the nature of these distributions, which can be inferred from mRNA sequencing data, and reconstruct the evolutionary history of cotranscriptional editing in the paramyxovirus family. Our model suggests that, throughout known history of the family, the system has switched from a P default to a V default mode four times; complete loss of the editing system has occurred twice, the canonical zinc finger domain of the V protein has been deleted or heavily mutated a further two times, and the W protein has independently evolved a novel function three times. Finally, we review the physical mechanisms of cotranscriptional editing via slippage of the viral RNA polymerase.
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Affiliation(s)
- Jordan Douglas
- Centre for Computational Evolution, University of Auckland, Auckland 1010, New Zealand
- School of Computer Science, University of Auckland, Auckland 1010, New Zealand
| | - Alexei J Drummond
- Centre for Computational Evolution, University of Auckland, Auckland 1010, New Zealand
- School of Biological Sciences, University of Auckland, Auckland 1010, New Zealand
| | - Richard L Kingston
- School of Biological Sciences, University of Auckland, Auckland 1010, New Zealand
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9
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Stat2 stability regulation: an intersection between immunity and carcinogenesis. Exp Mol Med 2020; 52:1526-1536. [PMID: 32973222 PMCID: PMC8080578 DOI: 10.1038/s12276-020-00506-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 07/28/2020] [Accepted: 07/28/2020] [Indexed: 11/18/2022] Open
Abstract
Signal transducer and activator of transcription (STAT2) is a member of the STAT family that plays an essential role in immune responses to extracellular and intracellular stimuli, including inflammatory reactions, invasion of foreign materials, and cancer initiation. Although the majority of STAT2 studies in the last few decades have focused on interferon (IFN)-α/β (IFNα/β) signaling pathway-mediated host defense against viral infections, recent studies have revealed that STAT2 also plays an important role in human cancer development. Notably, strategic research on STAT2 function has provided evidence that transient regulatory activity by homo- or heterodimerization induces its nuclear localization where it to forms a ternary IFN-stimulated gene factor 3 (ISGF3) complex, which is composed of STAT1 and/or STAT2 and IFN regulatory factor 9 (IEF9). The molecular mechanisms of ISGF3-mediated ISG gene expression provide the basic foundation for the regulation of STAT2 protein activity but not protein quality control. Recently, previously unknown molecular mechanisms of STAT2-mediated cell proliferation via STAT2 protein quality control were elucidated. In this review, we briefly summarize the role of STAT2 in immune responses and carcinogenesis with respect to the molecular mechanisms of STAT2 stability regulation via the proteasomal degradation pathway. The activity of STAT2, a protein stimulated by molecular signalling systems to activate selected genes in ways that can lead to cancer, is regulated by factors controlling its rate of degradation. Yong-Yeon Cho and colleagues at The Catholic University of Korea in South Korea review the role of STAT2 in links between molecular signals of the immune response and the onset of cancer. They focus on the significance of factors that regulate the stability of STAT2. One key factor appears to be the molecular mechanisms controlling the degradation of STAT2 by cellular structures called proteasomes. These structures break down proteins as part of routine cell maintenance. Deeper understanding of the stimulation, action and degradation of STAT2 will assist efforts to treat the many cancers in which STAT2 activity is involved.
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Wignall-Fleming EB, Vasou A, Young D, Short JAL, Hughes DJ, Goodbourn S, Randall RE. Innate Intracellular Antiviral Responses Restrict the Amplification of Defective Virus Genomes of Parainfluenza Virus 5. J Virol 2020; 94:e00246-20. [PMID: 32295916 PMCID: PMC7307174 DOI: 10.1128/jvi.00246-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 04/08/2020] [Indexed: 12/24/2022] Open
Abstract
During the replication of parainfluenza virus 5 (PIV5), copyback defective virus genomes (DVGs) are erroneously produced and are packaged into "infectious" virus particles. Copyback DVGs are the primary inducers of innate intracellular responses, including the interferon (IFN) response. While DVGs can interfere with the replication of nondefective (ND) virus genomes and activate the IFN-induction cascade before ND PIV5 can block the production of IFN, we demonstrate that the converse is also true, i.e., high levels of ND virus can block the ability of DVGs to activate the IFN-induction cascade. By following the replication and amplification of DVGs in A549 cells that are deficient in a variety of innate intracellular antiviral responses, we show that DVGs induce an uncharacterized IFN-independent innate response(s) that limits their replication. High-throughput sequencing was used to characterize the molecular structure of copyback DVGs. While there appears to be no sequence-specific break or rejoining points for the generation of copyback DVGs, our findings suggest there are region, size, and/or structural preferences selected for during for their amplification.IMPORTANCE Copyback defective virus genomes (DVGs) are powerful inducers of innate immune responses both in vitro and in vivo They impact the outcome of natural infections, may help drive virus-host coevolution, and promote virus persistence. Due to their potent interfering and immunostimulatory properties, DVGs may also be used therapeutically as antivirals and vaccine adjuvants. However, little is known of the host cell restrictions which limit their amplification. We show here that the generation of copyback DVGs readily occurs during parainfluenza virus 5 (PIV5) replication, but that their subsequent amplification is restricted by the induction of innate intracellular responses. Molecular characterization of PIV5 copyback DVGs suggests that while there are no genome sequence-specific breaks or rejoin points for the generation of copyback DVGs, genome region, size, and structural preferences are selected for during their evolution and amplification.
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Affiliation(s)
| | - Andri Vasou
- School of Biology, Centre for Biomolecular Sciences, University of St. Andrews, St. Andrews, United Kingdom
| | - Dan Young
- School of Biology, Centre for Biomolecular Sciences, University of St. Andrews, St. Andrews, United Kingdom
| | - John A L Short
- School of Biology, Centre for Biomolecular Sciences, University of St. Andrews, St. Andrews, United Kingdom
| | - David J Hughes
- School of Biology, Centre for Biomolecular Sciences, University of St. Andrews, St. Andrews, United Kingdom
| | - Steve Goodbourn
- Institute for Infection and Immunity, St. George's, University of London, London, United Kingdom
| | - Richard E Randall
- School of Biology, Centre for Biomolecular Sciences, University of St. Andrews, St. Andrews, United Kingdom
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11
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Mandhana R, Qian LK, Horvath CM. Constitutively Active MDA5 Proteins Are Inhibited by Paramyxovirus V Proteins. J Interferon Cytokine Res 2019; 38:319-332. [PMID: 30130154 DOI: 10.1089/jir.2018.0049] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Excessive interferon (IFN) production and signaling can lead to immunological and developmental defects giving rise to autoimmune diseases referred to collectively as "type I interferonopathies." A subset of these diseases is caused by monogenic mutations affecting proteins involved in nucleic acid sensing, homeostasis, and metabolism. Interferonopathic mutations in the cytosolic antiviral sensor MDA5 render it constitutively hyperactive, resulting in chronic IFN production and IFN-stimulated gene expression. Few therapeutic options are available for patients with interferonopathic diseases, but a large number of IFN evasion and antagonism strategies have evolved in viral pathogens that can counteract IFN production and signaling to enhance virus replication. To test the hypothesis that these natural IFN suppressors could be used to subdue the activity of interferonopathic signaling proteins, hyperactive MDA5 variants were assessed for susceptibility to a family of viral MDA5 inhibitors. In this study, Paramyxovirus V proteins were tested for their ability to counteract constitutively active MDA5 proteins. Results indicate that the V proteins are able to bind to and disrupt the signaling activity of these MDA5 proteins, irrespective of their specific mutations, reducing IFN production and IFN-stimulated gene expression to effectively suppress the hyperactive antiviral response.
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Affiliation(s)
- Roli Mandhana
- Department of Molecular Biosciences, Northwestern University , Evanston, Illinois
| | - Lily K Qian
- Department of Molecular Biosciences, Northwestern University , Evanston, Illinois
| | - Curt M Horvath
- Department of Molecular Biosciences, Northwestern University , Evanston, Illinois
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12
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Michalska A, Blaszczyk K, Wesoly J, Bluyssen HAR. A Positive Feedback Amplifier Circuit That Regulates Interferon (IFN)-Stimulated Gene Expression and Controls Type I and Type II IFN Responses. Front Immunol 2018; 9:1135. [PMID: 29892288 PMCID: PMC5985295 DOI: 10.3389/fimmu.2018.01135] [Citation(s) in RCA: 200] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 05/07/2018] [Indexed: 12/14/2022] Open
Abstract
Interferon (IFN)-I and IFN-II both induce IFN-stimulated gene (ISG) expression through Janus kinase (JAK)-dependent phosphorylation of signal transducer and activator of transcription (STAT) 1 and STAT2. STAT1 homodimers, known as γ-activated factor (GAF), activate transcription in response to all types of IFNs by direct binding to IFN-II activation site (γ-activated sequence)-containing genes. Association of interferon regulatory factor (IRF) 9 with STAT1–STAT2 heterodimers [known as interferon-stimulated gene factor 3 (ISGF3)] or with STAT2 homodimers (STAT2/IRF9) in response to IFN-I, redirects these complexes to a distinct group of target genes harboring the interferon-stimulated response element (ISRE). Similarly, IRF1 regulates expression of ISGs in response to IFN-I and IFN-II by directly binding the ISRE or IRF-responsive element. In addition, evidence is accumulating for an IFN-independent and -dependent role of unphosphorylated STAT1 and STAT2, with or without IRF9, and IRF1 in basal as well as long-term ISG expression. This review provides insight into the existence of an intracellular amplifier circuit regulating ISG expression and controlling long-term cellular responsiveness to IFN-I and IFN-II. The exact timely steps that take place during IFN-activated feedback regulation and the control of ISG transcription and long-term cellular responsiveness to IFN-I and IFN-II is currently not clear. Based on existing literature and our novel data, we predict the existence of a multifaceted intracellular amplifier circuit that depends on unphosphorylated and phosphorylated ISGF3 and GAF complexes and IRF1. In a combinatorial and timely fashion, these complexes mediate prolonged ISG expression and control cellular responsiveness to IFN-I and IFN-II. This proposed intracellular amplifier circuit also provides a molecular explanation for the existing overlap between IFN-I and IFN-II activated ISG expression.
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Affiliation(s)
- Agata Michalska
- Department of Human Molecular Genetics, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznan, Poland
| | - Katarzyna Blaszczyk
- Department of Human Molecular Genetics, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznan, Poland
| | - Joanna Wesoly
- Laboratory of High Throughput Technologies, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznan, Poland
| | - Hans A R Bluyssen
- Department of Human Molecular Genetics, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznan, Poland
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Sánchez-Aparicio MT, Feinman LJ, García-Sastre A, Shaw ML. Paramyxovirus V Proteins Interact with the RIG-I/TRIM25 Regulatory Complex and Inhibit RIG-I Signaling. J Virol 2018; 92:e01960-17. [PMID: 29321315 PMCID: PMC5827389 DOI: 10.1128/jvi.01960-17] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 12/18/2017] [Indexed: 02/06/2023] Open
Abstract
Paramyxovirus V proteins are known antagonists of the RIG-I-like receptor (RLR)-mediated interferon induction pathway, interacting with and inhibiting the RLR MDA5. We report interactions between the Nipah virus V protein and both RIG-I regulatory protein TRIM25 and RIG-I. We also observed interactions between these host proteins and the V proteins of measles virus, Sendai virus, and parainfluenza virus. These interactions are mediated by the conserved C-terminal domain of the V protein, which binds to the tandem caspase activation and recruitment domains (CARDs) of RIG-I (the region of TRIM25 ubiquitination) and to the SPRY domain of TRIM25, which mediates TRIM25 interaction with the RIG-I CARDs. Furthermore, we show that V interaction with TRIM25 and RIG-I prevents TRIM25-mediated ubiquitination of RIG-I and disrupts downstream RIG-I signaling to the mitochondrial antiviral signaling protein. This is a novel mechanism for innate immune inhibition by paramyxovirus V proteins, distinct from other known V protein functions such as MDA5 and STAT1 antagonism.IMPORTANCE The host RIG-I signaling pathway is a key early obstacle to paramyxovirus infection, as it results in rapid induction of an antiviral response. This study shows that paramyxovirus V proteins interact with and inhibit the activation of RIG-I, thereby interrupting the antiviral signaling pathway and facilitating virus replication.
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Affiliation(s)
- Maria T Sánchez-Aparicio
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Leighland J Feinman
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Adolfo García-Sastre
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Department of Medicine, Division of Infectious Diseases, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Megan L Shaw
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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Ribaudo M, Barik S. The nonstructural proteins of Pneumoviruses are remarkably distinct in substrate diversity and specificity. Virol J 2017; 14:215. [PMID: 29110727 PMCID: PMC5674761 DOI: 10.1186/s12985-017-0881-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 10/27/2017] [Indexed: 11/23/2022] Open
Abstract
Background Interferon (IFN) inhibits viruses by inducing several hundred cellular genes, aptly named ‘interferon (IFN)-stimulated genes’ (ISGs). The only two RNA viruses of the Pneumovirus genus of the Paramyxoviridae family, namely Respiratory Syncytial Virus (RSV) and Pneumonia Virus of Mice (PVM), each encode two nonstructural (NS) proteins that share no sequence similarity but yet suppress IFN. Since suppression of IFN underlies the ability of these viruses to replicate in the host cells, the mechanism of such suppression has become an important area of research. This Short Report is an important extension of our previous efforts in defining this mechanism. Results We show that, like their PVM counterparts, the RSV NS proteins also target multiple members of the ISG family. While significantly extending the substrate repertoire of the RSV NS proteins, these results, unexpectedly, also reveal that the target preferences of the NS proteins of the two viruses are entirely different. This is surprising since the two Pneumoviruses are phylogenetically close with similar genome organization and gene function, and the NS proteins of both also serve as suppressors of host IFN response. Conclusion The finding that the NS proteins of the two highly similar viruses suppress entirely different members of the ISG family raises intriguing questions of pneumoviral NS evolution and mechanism of action.
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Affiliation(s)
- Michael Ribaudo
- Department of Biological, Geological and Environmental Sciences, and Center for Gene Regulation in Health and Disease, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH, 44115, USA
| | - Sailen Barik
- Department of Biological, Geological and Environmental Sciences, and Center for Gene Regulation in Health and Disease, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH, 44115, USA. .,3780 Pelham Drive, Mobile, AL, 36619, USA.
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Liu Y, Olagnier D, Lin R. Host and Viral Modulation of RIG-I-Mediated Antiviral Immunity. Front Immunol 2017; 7:662. [PMID: 28096803 PMCID: PMC5206486 DOI: 10.3389/fimmu.2016.00662] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 12/16/2016] [Indexed: 12/21/2022] Open
Abstract
Innate immunity is the first line of defense against invading pathogens. Rapid and efficient detection of pathogen-associated molecular patterns via pattern-recognition receptors is essential for the host to mount defensive and protective responses. Retinoic acid-inducible gene-I (RIG-I) is critical in triggering antiviral and inflammatory responses for the control of viral replication in response to cytoplasmic virus-specific RNA structures. Upon viral RNA recognition, RIG-I recruits the mitochondrial adaptor protein mitochondrial antiviral signaling protein, which leads to a signaling cascade that coordinates the induction of type I interferons (IFNs), as well as a large variety of antiviral interferon-stimulated genes. The RIG-I activation is tightly regulated via various posttranslational modifications for the prevention of aberrant innate immune signaling. By contrast, viruses have evolved mechanisms of evasion, such as sequestrating viral structures from RIG-I detections and targeting receptor or signaling molecules for degradation. These virus–host interactions have broadened our understanding of viral pathogenesis and provided insights into the function of the RIG-I pathway. In this review, we summarize the recent advances regarding RIG-I pathogen recognition and signaling transduction, cell-intrinsic control of RIG-I activation, and the viral antagonism of RIG-I signaling.
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Affiliation(s)
- Yiliu Liu
- Jewish General Hospital, Lady Davis Institute, McGill University, Montreal, QC, Canada; Division of Experimental Medicine, McGill University, Montreal, QC, Canada
| | - David Olagnier
- Jewish General Hospital, Lady Davis Institute, McGill University, Montreal, QC, Canada; Division of Experimental Medicine, McGill University, Montreal, QC, Canada
| | - Rongtuan Lin
- Jewish General Hospital, Lady Davis Institute, McGill University, Montreal, QC, Canada; Division of Experimental Medicine, McGill University, Montreal, QC, Canada; Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
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Young DF, Andrejeva J, Li X, Inesta-Vaquera F, Dong C, Cowling VH, Goodbourn S, Randall RE. Human IFIT1 Inhibits mRNA Translation of Rubulaviruses but Not Other Members of the Paramyxoviridae Family. J Virol 2016; 90:9446-56. [PMID: 27512068 PMCID: PMC5044818 DOI: 10.1128/jvi.01056-16] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 08/03/2016] [Indexed: 12/24/2022] Open
Abstract
UNLABELLED We have previously shown that IFIT1 is primarily responsible for the antiviral action of interferon (IFN) alpha/beta against parainfluenza virus type 5 (PIV5), selectively inhibiting the translation of PIV5 mRNAs. Here we report that while PIV2, PIV5, and mumps virus (MuV) are sensitive to IFIT1, nonrubulavirus members of the paramyxoviridae such as PIV3, Sendai virus (SeV), and canine distemper virus (CDV) are resistant. The IFIT1 sensitivity of PIV5 was not rescued by coinfection with an IFIT1-resistant virus (PIV3), demonstrating that PIV3 does not specifically inhibit the antiviral activity of IFIT1 and that the inhibition of PIV5 mRNAs is regulated by cis-acting elements. We developed an in vitro translation system using purified human IFIT1 to further investigate the mechanism of action of IFIT1. While the translations of PIV2, PIV5, and MuV mRNAs were directly inhibited by IFIT1, the translations of PIV3, SeV, and CDV mRNAs were not. Using purified human mRNA-capping enzymes, we show biochemically that efficient inhibition by IFIT1 is dependent upon a 5' guanosine nucleoside cap (which need not be N7 methylated) and that this sensitivity is partly abrogated by 2'O methylation of the cap 1 ribose. Intriguingly, PIV5 M mRNA, in contrast to NP mRNA, remained sensitive to inhibition by IFIT1 following in vitro 2'O methylation, suggesting that other structural features of mRNAs may influence their sensitivity to IFIT1. Thus, surprisingly, the viral polymerases (which have 2'-O-methyltransferase activity) of rubulaviruses do not protect these viruses from inhibition by IFIT1. Possible biological consequences of this are discussed. IMPORTANCE Paramyxoviruses cause a wide variety of diseases, and yet most of their genes encode structural proteins and proteins involved in their replication cycle. Thus, the amount of genetic information that determines the type of disease that paramyxoviruses cause is relatively small. One factor that will influence disease outcomes is how they interact with innate host cell defenses, including the interferon (IFN) system. Here we show that different paramyxoviruses interact in distinct ways with cells in a preexisting IFN-induced antiviral state. Strikingly, all the rubulaviruses tested were sensitive to the antiviral action of ISG56/IFIT1, while all the other paramyxoviruses tested were resistant. We developed novel in vitro biochemical assays to investigate the mechanism of action of IFIT1, demonstrating that the mRNAs of rubulaviruses can be directly inhibited by IFIT1 and that this is at least partially because their mRNAs are not correctly methylated.
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Affiliation(s)
- D F Young
- School of Biology, Centre for Biomolecular Sciences, University of St. Andrews, St. Andrews, Fife, United Kingdom
| | - J Andrejeva
- School of Biology, Centre for Biomolecular Sciences, University of St. Andrews, St. Andrews, Fife, United Kingdom
| | - X Li
- Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, United Kingdom
| | - F Inesta-Vaquera
- School of Life Sciences, Centre for Gene Regulation and Expression, University of Dundee, Dundee, United Kingdom
| | - C Dong
- Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, United Kingdom
| | - V H Cowling
- School of Life Sciences, Centre for Gene Regulation and Expression, University of Dundee, Dundee, United Kingdom
| | - S Goodbourn
- Institute for Infection and Immunity, St. George's, University of London, London, United Kingdom
| | - R E Randall
- School of Biology, Centre for Biomolecular Sciences, University of St. Andrews, St. Andrews, Fife, United Kingdom
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The unique role of STAT2 in constitutive and IFN-induced transcription and antiviral responses. Cytokine Growth Factor Rev 2016; 29:71-81. [PMID: 27053489 DOI: 10.1016/j.cytogfr.2016.02.010] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 02/27/2016] [Indexed: 11/20/2022]
Abstract
In the canonical pathway of IFN-I-mediated signaling, phosphorylation of STAT1 and STAT2 leads to heterodimerization and interaction with IRF9. This complex, also known as IFN-stimulated gene factor 3 (ISGF3), then translocates into the nucleus and binds the IFN-I-stimulated response element (ISRE) leading to the activation of transcription of over 300 interferon stimulated genes (ISGs). In addition, STAT1 homodimers [known as γ-activated factor (GAF)] are formed and translocate to the nucleus, where they target genes containing the γ-activated sequence (GAS). The primary function of ISGF3 is to mediate a rapid and robust IFN-I activated response by regulating transient transcription of antiviral ISGs. This requires the quick assembly of ISGF3 from its pre-existing components STAT1, STAT2 and IRF9 and transport to the nucleus to bind ISRE-containing ISGs. The exact events that take place in formation, nuclear translocation and DNA-binding of active ISGF3 are still not clear. Over the years many studies have provided evidence for the existence of a multitude of alternative STAT2-containing (ISRE or GAS-binding) complexes involved in IFN-I signaling, emphasizing the importance of STAT2 in the regulation of specific IFN-I-induced transcriptional programs, independent of its involvement in the classical ISGF3 complex. This review describes the unique role of STAT2 in differential complex formation of unphosphorylated and phosphorylated ISGF3 components that direct constitutive and IFN-I-stimulated transcriptional responses. In addition, we highlight the existence of a STAT1-independent IFN-I signaling pathway, where STAT2/IRF9 can potentially substitute for the role of ISGF3 and offer a back-up response against viral infection.
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18
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Pisanelli G, Laurent-Rolle M, Manicassamy B, Belicha-Villanueva A, Morrison J, Lozano-Dubernard B, Castro-Peralta F, Iovane G, García-Sastre A. La Piedad Michoacán Mexico Virus V protein antagonizes type I interferon response by binding STAT2 protein and preventing STATs nuclear translocation. Virus Res 2015; 213:11-22. [PMID: 26546155 DOI: 10.1016/j.virusres.2015.10.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Revised: 10/30/2015] [Accepted: 10/30/2015] [Indexed: 12/24/2022]
Abstract
La Piedad Michoacán Mexico Virus (LPMV) is a member of the Rubulavirus genus within the Paramyxoviridae family. LPMV is the etiologic agent of "blue eye disease", causing a significant disease burden in swine in Mexico with long-term implications for the agricultural industry. This virus mainly affects piglets and is characterized by meningoencephalitis and respiratory distress. It also affects adult pigs, causing reduced fertility and abortions in females, and orchitis and epididymitis in males. Viruses of the Paramyxoviridae family evade the innate immune response by targeting components of the interferon (IFN) signaling pathway. The V protein, expressed by most paramyxoviruses, is a well-characterized IFN signaling antagonist. Until now, there were no reports on the role of the LPMV-V protein in inhibiting the IFN response. In this study we demonstrate that LPMV-V protein antagonizes type I but not type II IFN signaling by binding STAT2, a component of the type I IFN cascade. Our results indicate that the last 18 amino acids of LPMV-V protein are required for binding to STAT2 in human and swine cells. While LPMV-V protein does not affect the protein levels of STAT1 or STAT2, it does prevent the IFN-induced phosphorylation and nuclear translocation of STAT1 and STAT2 thereby inhibiting cellular responses to IFN α/β.
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Affiliation(s)
- Giuseppe Pisanelli
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, United States; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, United States; Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Via Federico Delpino 1, 80137 Naples, Italy
| | - Maudry Laurent-Rolle
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, United States; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, United States
| | - Balaji Manicassamy
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, United States; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, United States
| | - Alan Belicha-Villanueva
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, United States; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, United States
| | - Juliet Morrison
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, United States; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, United States
| | - Bernardo Lozano-Dubernard
- Departamento de Investigación y Desarrollo, Laboratorio Avi-Mex, SA de CV, Bartolache 1862, Colonia del Valle, D.F. México 01900, Mexico
| | - Felipa Castro-Peralta
- Departamento de Investigación y Desarrollo, Laboratorio Avi-Mex, SA de CV, Bartolache 1862, Colonia del Valle, D.F. México 01900, Mexico
| | - Giuseppe Iovane
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Via Federico Delpino 1, 80137 Naples, Italy
| | - Adolfo García-Sastre
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, United States; Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, United States; Department of Medicine, Division of Infectious Disease, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, United States.
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19
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Abdul-Sater AA, Majoros A, Plumlee CR, Perry S, Gu AD, Lee C, Shresta S, Decker T, Schindler C. Different STAT Transcription Complexes Drive Early and Delayed Responses to Type I IFNs. THE JOURNAL OF IMMUNOLOGY 2015; 195:210-216. [PMID: 26019270 DOI: 10.4049/jimmunol.1401139] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 04/24/2015] [Indexed: 01/12/2023]
Abstract
IFNs, which transduce pivotal signals through Stat1 and Stat2, effectively suppress the replication of Legionella pneumophila in primary murine macrophages. Although the ability of IFN-γ to impede L. pneumophila growth is fully dependent on Stat1, IFN-αβ unexpectedly suppresses L. pneumophila growth in both Stat1- and Stat2-deficient macrophages. New studies demonstrating that the robust response to IFN-αβ is lost in Stat1-Stat2 double-knockout macrophages suggest that Stat1 and Stat2 are functionally redundant in their ability to direct an innate response toward L. pneumophila. Because the ability of IFN-αβ to signal through Stat1-dependent complexes (i.e., Stat1-Stat1 and Stat1-Stat2 dimers) has been well characterized, the current studies focus on how Stat2 is able to direct a potent response to IFN-αβ in the absence of Stat1. These studies reveal that IFN-αβ is able to drive the formation of a Stat2 and IFN regulatory factor 9 complex that drives the expression of a subset of IFN-stimulated genes, but with substantially delayed kinetics. These observations raise the possibility that this pathway evolved in response to microbes that have devised strategies to subvert Stat1-dependent responses.
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Affiliation(s)
- Ali A Abdul-Sater
- Department of Microbiology & Immunology, Columbia University, New York, NY 10032 USA
| | - Andrea Majoros
- Department of Microbiology, Immunology & Genetics, University of Vienna, Vienna A-1030 Austria
| | - Courtney R Plumlee
- Department of Microbiology & Immunology, Columbia University, New York, NY 10032 USA
| | - Stuart Perry
- Division of Vaccine Discovery, La Jolla Inst. for Allergy and Immunology, La Jolla, CA 92037 USA
| | - Ai Di Gu
- Department of Microbiology & Immunology, Columbia University, New York, NY 10032 USA
| | - Carolyn Lee
- Department of Microbiology & Immunology, Columbia University, New York, NY 10032 USA
| | - Sujan Shresta
- Division of Vaccine Discovery, La Jolla Inst. for Allergy and Immunology, La Jolla, CA 92037 USA
| | - Thomas Decker
- Department of Microbiology, Immunology & Genetics, University of Vienna, Vienna A-1030 Austria
| | - Christian Schindler
- Department of Microbiology & Immunology, Columbia University, New York, NY 10032 USA.,Department of Medicine, Columbia University, New York, NY 10032 USA
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Pfaller CK, Cattaneo R, Schnell MJ. Reverse genetics of Mononegavirales: How they work, new vaccines, and new cancer therapeutics. Virology 2015; 479-480:331-44. [PMID: 25702088 DOI: 10.1016/j.virol.2015.01.029] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Revised: 01/26/2015] [Accepted: 01/30/2015] [Indexed: 12/24/2022]
Abstract
The order Mononegavirales includes five families: Bornaviridae, Filoviridae, Nyamaviridae, Paramyxoviridae, and Rhabdoviridae. The genome of these viruses is one molecule of negative-sense single strand RNA coding for five to ten genes in a conserved order. The RNA is not infectious until packaged by the nucleocapsid protein and transcribed by the polymerase and co-factors. Reverse genetics approaches have answered fundamental questions about the biology of Mononegavirales. The lack of icosahedral symmetry and modular organization in the genome of these viruses has facilitated engineering of viruses expressing fluorescent proteins, and these fluorescent proteins have provided important insights about the molecular and cellular basis of tissue tropism and pathogenesis. Studies have assessed the relevance for virulence of different receptors and the interactions with cellular proteins governing the innate immune responses. Research has also analyzed the mechanisms of attenuation. Based on these findings, ongoing clinical trials are exploring new live attenuated vaccines and the use of viruses re-engineered as cancer therapeutics.
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Affiliation(s)
| | - Roberto Cattaneo
- Department of Molecular Medicine, Mayo Clinic, Rochester, MN 55905, USA.
| | - Matthias J Schnell
- Department of Microbiology and Immunology, Philadelphia, PA 19107, USA; Jefferson Vaccine Center, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA.
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Stahl P, Schwarz RT, Debierre-Grockiego F, Meyer T. Trypanosoma cruzi parasites fight for control of the JAK-STAT pathway by disarming their host. JAKSTAT 2015; 3:e1012964. [PMID: 26413423 DOI: 10.1080/21623996.2015.1012964] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2015] [Revised: 01/23/2015] [Accepted: 01/26/2015] [Indexed: 12/13/2022] Open
Abstract
The zoonotic Chagas' disease is caused by infections with the hemoflagellate Trypanosoma cruzi (T. cruzi) which is endemic in Latin America. Despite recent advances in our understanding of the pathogenesis of the disease, the underlying molecular processes involved in host-parasite interactions are only poorly understood. In particular, the mechanisms for parasite persistence in host cells remain largely unknown. Cytokine-driven transcription factors from the family of STAT (signal transducer and activator of transcription) proteins appear to play a central role in the fight against T. cruzi infection. However, amastigotes proliferating in the cytoplasm of infected host cells develop effective strategies to circumvent the attack executed by STAT proteins. This review highlights the interactions between T. cruzi parasites and human host cells in terms of cytokine signaling and, in particular, discusses the impact of STATs on the balance between parasite invasion and clearance.
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Affiliation(s)
- Philipp Stahl
- Institute of Virology; Parasitology Unit; University of Marburg ; Marburg, Germany
| | - Ralph T Schwarz
- Institute of Virology; Parasitology Unit; University of Marburg ; Marburg, Germany ; Laboratory for Structural and Functional Glycobiology; University of Lille 1 for Sciences and Technologies ; Lille, France
| | - Françoise Debierre-Grockiego
- Mixed Research Unit 1282; François Rabelais University of Tours-INRA; Infectious Diseases and Public Health ; Tours, France
| | - Thomas Meyer
- Department of Psychosomatic Medicine and Psychotherapy; University of Göttingen ; Göttingen, Germany ; German Center for Cardiovascular Research ; Göttingen, Germany
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Disruption of type I interferon signaling by the nonstructural protein of severe fever with thrombocytopenia syndrome virus via the hijacking of STAT2 and STAT1 into inclusion bodies. J Virol 2015; 89:4227-36. [PMID: 25631085 DOI: 10.1128/jvi.00154-15] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The type I interferon (IFN) system, including IFN induction and signaling, is the critical component of the host defense line against viral infection, which, in turn, is also a vulnerable target for viral immune evasion. Severe fever with thrombocytopenia syndrome virus (SFTSV) is an emerging bunyavirus. Previous data have shown that SFTSV can interfere with the early induction of type I IFNs through targeting host kinases TBK1/IKKε. In this study, we demonstrated that SFTSV also can suppress type I IFN-triggered signaling and interferon-stimulated gene (ISG) expression. Interestingly, we observed the significant inhibition of IFN signaling in cells transfected with the plasmids encoding the nonstructural protein (NSs) but not the nucleocapsid protein (NP), indicating the role of NSs as an antagonist of IFN signaling. Furthermore, coimmunoprecipitation (Co-IP) and pulldown assays indicated that NSs interacts with the cellular signal transducer and activator of transcription 2 (STAT2), and the DNA-binding domain of STAT2 may contribute to the NSs-STAT2 interaction. Combined with confocal microscopy analyses, we demonstrated that NSs sequesters STAT2 and STAT1 into viral inclusion bodies (IBs) and impairs IFN-induced STAT2 phosphorylation and nuclear translocation of both STATs, resulting in the inhibition of IFN signaling and ISG expression. SFTSV NSs-mediated hijacking of STATs in IBs represents a novel mechanism of viral suppression of IFN signaling, highlighting the role of viral IBs as the virus-built "jail" sequestering some crucial host factors and interfering with the corresponding cellular processes. IMPORTANCE SFTSV is an emerging bunyavirus which can cause a severe hemorrhagic fever-like disease with high case fatality rates in humans, posing a serious health threat. However, there are no specific antivirals available, and the pathogenesis and virus-host interactions are largely unclear. Here, we demonstrated that SFTSV can inhibit type I IFN antiviral signaling by the NSs-mediated hijacking of STAT2 and STAT1 into viral IBs, highlighting the interesting role of viral IBs in virus-host interactions as the virus-built jail. Sequestering signaling molecules into IBs represents a novel and, perhaps, also a general mechanism of viral suppression of IFN signaling, the understanding of which may benefit the study of viral pathogenesis and the development of antiviral therapies.
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Stahl P, Ruppert V, Schwarz RT, Meyer T. Trypanosoma cruzi evades the protective role of interferon-gamma-signaling in parasite-infected cells. PLoS One 2014; 9:e110512. [PMID: 25340519 PMCID: PMC4207753 DOI: 10.1371/journal.pone.0110512] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 09/23/2014] [Indexed: 12/15/2022] Open
Abstract
The protozoan parasite Trypanosoma cruzi is responsible for the zoonotic Chagas disease, a chronic and systemic infection in humans and warm-blooded animals typically leading to progressive dilated cardiomyopathy and gastrointestinal manifestations. In the present study, we report that the transcription factor STAT1 (signal transducer and activator of transcription 1) reduces the susceptibility of human cells to infection with T. cruzi. Our in vitro data demonstrate that interferon -γ (IFNγ) pre-treatment causes T. cruzi-infected cells to enter an anti-parasitic state through the activation of the transcription factor STAT1. Whereas stimulation of STAT1-expressing cells with IFNγ significantly impaired intracellular replication of parasites, no protective effect of IFNγ was observed in STAT1-deficient U3A cells. The gene encoding indoleamine 2, 3-dioxygenase (ido) was identified as a STAT1-regulated target gene engaged in parasite clearance. Exposure of cells to T. cruzi trypomastigotes in the absence of IFNγ resulted in both sustained tyrosine and serine phosphorylation of STAT1 and its increased DNA binding. Furthermore, we found that in response to T. cruzi the total amount of intracellular STAT1 increased in an infectious dose-dependent manner, both at the mRNA and protein level. While STAT1 activation is a potent strategy of the host in the fight against the invading pathogen, amastigotes replicating intracellularly antagonize this pathway by specifically promoting the dephosphorylation of STAT1 serine 727, thereby partially circumventing its protective effects. These findings point to the crucial role of the IFNγ/STAT1 signal pathway in the evolutionary combat between T. cruzi parasites and their host.
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Affiliation(s)
- Philipp Stahl
- Institut für Virologie, AG Parasitologie, Philipps-Universität Marburg, Marburg, Germany
| | - Volker Ruppert
- Klinik für Kardiologie, Philipps-Universität Marburg, Marburg, Germany
| | - Ralph T. Schwarz
- Institut für Virologie, AG Parasitologie, Philipps-Universität Marburg, Marburg, Germany
- Unité de Glycobiologie Structurale et Fonctionnelle, UMR CNRS/USTL n° 8576, Université de Lille1 Sciences et Technologies, Villeneuve d'Ascq, France
| | - Thomas Meyer
- Klinik für Psychosomatische Medizin und Psychotherapie, Georg-August-Universität Göttingen, Göttingen, Germany
- * E-mail:
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EVM005: an ectromelia-encoded protein with dual roles in NF-κB inhibition and virulence. PLoS Pathog 2014; 10:e1004326. [PMID: 25122471 PMCID: PMC4133408 DOI: 10.1371/journal.ppat.1004326] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 07/07/2014] [Indexed: 11/19/2022] Open
Abstract
Poxviruses contain large dsDNA genomes encoding numerous open reading frames that manipulate cellular signalling pathways and interfere with the host immune response. The NF-κB signalling cascade is an important mediator of innate immunity and inflammation, and is tightly regulated by ubiquitination at several key points. A critical step in NF-κB activation is the ubiquitination and degradation of the inhibitor of kappaB (IκBα), by the cellular SCFβ-TRCP ubiquitin ligase complex. We show here that upon stimulation with TNFα or IL-1β, Orthopoxvirus-infected cells displayed an accumulation of phosphorylated IκBα, indicating that NF-κB activation was inhibited during poxvirus infection. Ectromelia virus is the causative agent of lethal mousepox, a natural disease that is fatal in mice. Previously, we identified a family of four ectromelia virus genes (EVM002, EVM005, EVM154 and EVM165) that contain N-terminal ankyrin repeats and C-terminal F-box domains that interact with the cellular SCF ubiquitin ligase complex. Since degradation of IκBα is catalyzed by the SCFβ-TRCP ubiquitin ligase, we investigated the role of the ectromelia virus ankyrin/F-box protein, EVM005, in the regulation of NF-κB. Expression of Flag-EVM005 inhibited both TNFα- and IL-1β-stimulated IκBα degradation and p65 nuclear translocation. Inhibition of the NF-κB pathway by EVM005 was dependent on the F-box domain, and interaction with the SCF complex. Additionally, ectromelia virus devoid of EVM005 was shown to inhibit NF-κB activation, despite lacking the EVM005 open reading frame. Finally, ectromelia virus devoid of EVM005 was attenuated in both A/NCR and C57BL/6 mouse models, indicating that EVM005 is required for virulence and immune regulation in vivo. Poxviruses are large dsDNA viruses that are renowned for regulating cellular pathways and manipulating the host immune response, including the NF-κB pathway. NF-κB inhibition by poxviruses is a growing area of interest and this family of viruses has developed multiple mechanisms to manipulate the pathway. Here, we focus on regulation of the NF-κB pathway by ectromelia virus, the causative agent of mousepox. We demonstrate that ectromelia virus is a potent inhibitor of the NF-κB pathway. Previously, we identified a family of four ectromelia virus genes that contain N-terminal ankyrin repeats and a C-terminal F-box domain that interacts with the cellular SCF ubiquitin ligase. Significantly, expression of the ankyrin/F-box protein, EVM005, inhibited NF-κB, and the F-box domain was critical for NF-κB inhibition and interaction with the SCF complex. Ectromelia virus devoid of EVM005 still inhibited NF-κB, indicating that multiple gene products contribute to NF-κB inhibition. Importantly, mice infected with ectromelia virus lacking EVM005 had a robust immune response, leading to viral clearance during infection. The data present two mechanisms, one in which EVM005 inhibits NF-κB activation through manipulation of the host SCF ubiquitin ligase complex, and an additional, NF-κB-independent mechanism that drives virulence.
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Holloway G, Dang VT, Jans DA, Coulson BS. Rotavirus inhibits IFN-induced STAT nuclear translocation by a mechanism that acts after STAT binding to importin-α. J Gen Virol 2014; 95:1723-1733. [DOI: 10.1099/vir.0.064063-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The importance of innate immunity to rotaviruses is exemplified by the range of strategies evolved by rotaviruses to interfere with the IFN response. We showed previously that rotaviruses block gene expression induced by type I and II IFNs, through a mechanism allowing activation of signal transducer and activator of transcription (STAT) 1 and STAT2 but preventing their nuclear accumulation. This normally occurs through activated STAT1/2 dimerization, enabling an interaction with importin α5 that mediates transport into the nucleus. In rotavirus-infected cells, STAT1/2 inhibition may limit the antiviral actions of IFN produced early in infection. Here we further analysed the block to STAT1/2 nuclear accumulation, showing that activated STAT1 accumulates in the cytoplasm in rotavirus-infected cells. STAT1/2 nuclear accumulation was inhibited by rotavirus even in the presence of the nuclear export inhibitor Leptomycin B, demonstrating that enhanced nuclear export is not involved in STAT1/2 cytoplasmic retention. The ability to inhibit STAT nuclear translocation was completely conserved amongst the group A rotaviruses tested, including a divergent avian strain. Analysis of mutant rotaviruses indicated that residues after amino acid 47 of NSP1 are dispensable for STAT inhibition. Furthermore, expression of any of the 12 Rhesus monkey rotavirus proteins did not inhibit IFN-stimulated STAT1 nuclear translocation. Finally, co-immunoprecipitation experiments from transfected epithelial cells showed that STAT1/2 binds importin α5 normally following rotavirus infection. These findings demonstrate that rotavirus probably employs a novel strategy to inhibit IFN-induced STAT signalling, which acts after STAT activation and binding to the nuclear import machinery.
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Affiliation(s)
- Gavan Holloway
- Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Victoria 3010, Australia
| | - Vi T. Dang
- Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Victoria 3010, Australia
| | - David A. Jans
- Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia
| | - Barbara S. Coulson
- Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Victoria 3010, Australia
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Mesman AW, Zijlstra-Willems EM, Kaptein TM, de Swart RL, Davis ME, Ludlow M, Duprex WP, Gack MU, Gringhuis SI, Geijtenbeek TBH. Measles virus suppresses RIG-I-like receptor activation in dendritic cells via DC-SIGN-mediated inhibition of PP1 phosphatases. Cell Host Microbe 2014; 16:31-42. [PMID: 25011106 PMCID: PMC4159752 DOI: 10.1016/j.chom.2014.06.008] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 04/02/2014] [Accepted: 05/21/2014] [Indexed: 12/12/2022]
Abstract
Dendritic cells (DCs) are targets of measles virus (MV) and play central roles in viral dissemination. However, DCs express the RIG-I-like receptors (RLRs) RIG-I and Mda5 that sense MV and induce type I interferon (IFN) production. Given the potency of this antiviral response, RLRs are tightly regulated at various steps, including dephosphorylation by PP1 phosphatases, which induces their activation. We demonstrate that MV suppresses RIG-I and Mda5 by activating the C-type lectin DC-SIGN and inducing signaling that prevents RLR dephosphorylation. MV binding to DC-SIGN leads to activation of the kinase Raf-1, which induces the association of PP1 inhibitor I-1 with GADD34-PP1 holoenzymes, thereby inhibiting phosphatase activity. Consequently, GADD34-PP1 holoenzymes are unable to dephosphorylate RIG-I and Mda5, hence suppressing type I IFN responses and enhancing MV replication. Blocking DC-SIGN signaling allows RLR activation and suppresses MV infection of DCs. Thus, MV subverts DC-SIGN to control RLR activation and escape antiviral responses.
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Affiliation(s)
- Annelies W Mesman
- Department of Experimental Immunology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands
| | - Esther M Zijlstra-Willems
- Department of Experimental Immunology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands
| | - Tanja M Kaptein
- Department of Experimental Immunology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands
| | - Rik L de Swart
- Department of Virology, Erasmus MC, 's-Gravendijkwal 230, 3015 CA Rotterdam, the Netherlands
| | - Meredith E Davis
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Martin Ludlow
- Department of Microbiology, Boston University, School of Medicine, Boston, MA 02118, USA
| | - W Paul Duprex
- Department of Microbiology, Boston University, School of Medicine, Boston, MA 02118, USA
| | - Michaela U Gack
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Sonja I Gringhuis
- Department of Experimental Immunology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands.
| | - Teunis B H Geijtenbeek
- Department of Experimental Immunology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands.
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Chowdhury FZ, Farrar JD. STAT2: A shape-shifting anti-viral super STAT. JAKSTAT 2014; 2:e23633. [PMID: 24058798 PMCID: PMC3670274 DOI: 10.4161/jkst.23633] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Revised: 01/11/2013] [Accepted: 01/15/2013] [Indexed: 12/24/2022] Open
Abstract
STAT2 is unique among the STAT family of transcription factors in that its activation is driven predominantly by only two classes of cell surface receptors: Type I and III interferon receptors. As such, STAT2 plays a critical role in host defenses against viral infections. Viruses have evolved to target STAT2 by either inhibiting its expression, blocking its activity, or by targeting it for degradation. Consequently, these viral onslaughts have driven remarkable divergence in the STAT2 gene across species that is not observed in other STAT family members. Thus, the evolution of STAT2 may preserve its activity and protect each species in the face of an ever-changing viral community.
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Affiliation(s)
- Fatema Z Chowdhury
- Department of Immunology and Department of Molecular Biology; UT Southwestern Medical Center; Dallas, TX USA
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Paramyxovirus V protein interaction with the antiviral sensor LGP2 disrupts MDA5 signaling enhancement but is not relevant to LGP2-mediated RLR signaling inhibition. J Virol 2014; 88:8180-8. [PMID: 24829334 DOI: 10.1128/jvi.00737-14] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The interferon antiviral system is a primary barrier to virus replication triggered upon recognition of nonself RNAs by the cytoplasmic sensors encoded by retinoic acid-inducible gene I (RIG-I), melanoma differentiation-associated gene 5 (MDA5), and laboratory of genetics and physiology gene 2 (LGP2). Paramyxovirus V proteins are interferon antagonists that can selectively interact with MDA5 and LGP2 through contact with a discrete helicase domain region. Interaction with MDA5, an activator of antiviral signaling, disrupts interferon gene expression and antiviral responses. LGP2 has more diverse reported roles as both a coactivator of MDA5 and a negative regulator of both RIG-I and MDA5. This functional dichotomy, along with the concurrent interference with both cellular targets, has made it difficult to assess the unique consequences of V protein interaction with LGP2. To directly evaluate the impact of LGP2 interference, MDA5 and LGP2 variants unable to be recognized by measles virus and parainfluenza virus 5 (PIV5) V proteins were tested in signaling assays. Results indicate that interaction with LGP2 specifically prevents coactivation of MDA5 signaling and that LGP2's negative regulatory capacity was not affected. V proteins only partially antagonize RIG-I at high concentrations, and their expression had no additive effects on LGP2-mediated negative regulation. However, conversion of RIG-I to a direct V protein target was accomplished by only two amino acid substitutions that allowed both V protein interaction and efficient interference. These results clarify the unique consequences of MDA5 and LGP2 interference by paramyxovirus V proteins and help resolve the distinct roles of LGP2 in both activation and inhibition of antiviral signal transduction. Importance: Paramyxovirus V proteins interact with two innate immune receptors, MDA5 and LGP2, but not RIG-I. V proteins prevent MDA5 from signaling to the beta interferon promoter, but the consequences of LGP2 targeting are poorly understood. As the V protein targets MDA5 and LGP2 simultaneously, and LGP2 is both a positive and negative regulator of both MDA5 and RIG-I, it has been difficult to evaluate the specific advantages conferred by LGP2 targeting. Experiments with V-insensitive proteins revealed that the primary outcome of LGP2 interference is suppression of its ability to synergize with MDA5. LGP2's negative regulation of MDA5 and RIG-I remains intact irrespective of V protein interaction. Complementary experiments demonstrate that RIG-I can be converted to V protein sensitivity by two amino acid substitutions. These findings clarify the functions of LGP2 as a positive regulator of MDA5 signaling, demonstrate the basis for V-mediated LGP2 targeting, and broaden our understanding of paramyxovirus-host interactions.
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Wiltzer L, Okada K, Yamaoka S, Larrous F, Kuusisto HV, Sugiyama M, Blondel D, Bourhy H, Jans DA, Ito N, Moseley GW. Interaction of Rabies Virus P-Protein With STAT Proteins is Critical to Lethal Rabies Disease. J Infect Dis 2013; 209:1744-53. [DOI: 10.1093/infdis/jit829] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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Vijayan M, Seo YJ, Pritzl CJ, Squires SA, Alexander S, Hahm B. Sphingosine kinase 1 regulates measles virus replication. Virology 2013; 450-451:55-63. [PMID: 24503067 DOI: 10.1016/j.virol.2013.11.039] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Revised: 10/21/2013] [Accepted: 11/26/2013] [Indexed: 12/21/2022]
Abstract
Measles virus (MV) manipulates host factors to facilitate virus replication. Sphingosine kinase (SK) is an enzyme catalyzing the formation of sphingosine 1-phosphate and modulates multiple cellular processes including the host defense system. Here, we determined the role of SK1 in MV replication. Overexpression of SK1 enhanced MV replication. In contrast, inhibition of SK impaired viral protein expression and infectious virus production from cells expressing MV receptor, SLAM or Nectin-4. The inhibition of virus replication was observed when the cells were infected by vaccine strain or wild type MV or V/C gene-deficient MV. Importantly, SK inhibition suppressed MV-induced activation of NF-κB. The inhibitors specific to NF-κB signal pathway repressed the synthesis of MV proteins, revealing the importance of NF-κB activation for efficient MV replication. Therefore, SK inhibition restricts MV replication and modulates the NF-κB signal pathway, demonstrating that SK is a cellular factor critical for MV replication.
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Affiliation(s)
- Madhuvanthi Vijayan
- Departments of Surgery & Molecular Microbiology and Immunology, University of Missouri-Columbia, Columbia, MO 65212, USA
| | - Young-Jin Seo
- Departments of Surgery & Molecular Microbiology and Immunology, University of Missouri-Columbia, Columbia, MO 65212, USA
| | - Curtis John Pritzl
- Departments of Surgery & Molecular Microbiology and Immunology, University of Missouri-Columbia, Columbia, MO 65212, USA
| | - Sarah Angela Squires
- Departments of Surgery & Molecular Microbiology and Immunology, University of Missouri-Columbia, Columbia, MO 65212, USA
| | - Stephen Alexander
- Division of Biological Sciences, University of Missouri-Columbia, Columbia, MO, USA
| | - Bumsuk Hahm
- Departments of Surgery & Molecular Microbiology and Immunology, University of Missouri-Columbia, Columbia, MO 65212, USA.
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31
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Paramyxovirus activation and inhibition of innate immune responses. J Mol Biol 2013; 425:4872-92. [PMID: 24056173 DOI: 10.1016/j.jmb.2013.09.015] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 09/12/2013] [Accepted: 09/12/2013] [Indexed: 12/18/2022]
Abstract
Paramyxoviruses represent a remarkably diverse family of enveloped nonsegmented negative-strand RNA viruses, some of which are the most ubiquitous disease-causing viruses of humans and animals. This review focuses on paramyxovirus activation of innate immune pathways, the mechanisms by which these RNA viruses counteract these pathways, and the innate response to paramyxovirus infection of dendritic cells (DC). Paramyxoviruses are potent activators of extracellular complement pathways, a first line of defense that viruses must face during natural infections. We discuss mechanisms by which these viruses activate and combat complement to delay neutralization. Once cells are infected, virus replication drives type I interferon (IFN) synthesis that has the potential to induce a large number of antiviral genes. Here we describe four approaches by which paramyxoviruses limit IFN induction: by limiting synthesis of IFN-inducing aberrant viral RNAs, through targeted inhibition of RNA sensors, by providing viral decoy substrates for cellular kinase complexes, and through direct blocking of the IFN promoter. In addition, paramyxoviruses have evolved diverse mechanisms to disrupt IFN signaling pathways. We describe three general mechanisms, including targeted proteolysis of signaling factors, sequestering cellular factors, and upregulation of cellular inhibitors. DC are exceptional cells with the capacity to generate adaptive immunity through the coupling of innate immune signals and T cell activation. We discuss the importance of innate responses in DC following paramyxovirus infection and their consequences for the ability to mount and maintain antiviral T cells.
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32
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Dual myxovirus screen identifies a small-molecule agonist of the host antiviral response. J Virol 2013; 87:11076-87. [PMID: 23926334 DOI: 10.1128/jvi.01425-13] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
As we are confronted with an increasing number of emerging and reemerging viral pathogens, the identification of novel pathogen-specific and broad-spectrum antivirals has become a major developmental objective. Targeting of host factors required for virus replication presents a tangible approach toward obtaining novel hits with a broadened indication range. However, the identification of developable host-directed antiviral candidates remains challenging. We describe a novel screening protocol that interrogates the myxovirus host-pathogen interactome for broad-spectrum drug candidates and simultaneously probes for conventional, pathogen-directed hits. With resource efficiency and pan-myxovirus activity as the central developmental parameters, we explored coscreening against two distinct, independently traceable myxoviruses in a single-well setting. Having identified a pair of unrelated pathogenic myxoviruses (influenza A virus and measles virus) with comparable replication kinetics, we observed unimpaired coreplication of both viruses, generated suitable firefly and Renilla luciferase reporter constructs, respectively, and validated the protocol for up to a 384-well plate format. Combined with an independent counterscreen using a recombinant respiratory syncytial virus luciferase reporter, implementation of the protocol identified candidates with a broadened antimyxovirus profile, in addition to pathogen-specific hits. Mechanistic characterization revealed a newly discovered broad-spectrum lead that does not block viral entry but stimulates effector pathways of the innate cellular antiviral response. In summary, we provide proof of concept for the efficient discovery of broad-spectrum myxovirus inhibitors in parallel to para- and orthomyxovirus-specific hit candidates in a single screening campaign. The newly identified compound provides a basis for the development of a novel broad-spectrum small-molecule antiviral class.
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33
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Rajsbaum R, García-Sastre A. Viral evasion mechanisms of early antiviral responses involving regulation of ubiquitin pathways. Trends Microbiol 2013; 21:421-9. [PMID: 23850008 PMCID: PMC3740364 DOI: 10.1016/j.tim.2013.06.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 06/12/2013] [Accepted: 06/14/2013] [Indexed: 12/29/2022]
Abstract
Innate and restriction factors are essential to protect host cells against viruses. Dual roles of antiviral factors: direct viral inhibition versus innate immune signaling. Viruses antagonize the antiviral response by manipulating ubiquitin E3 ligases. Viruses target restriction factors for ubiquitin-dependent degradation.
Early innate and cell-intrinsic responses are essential to protect host cells against pathogens. In turn, viruses have developed sophisticated mechanisms to establish productive infections by counteracting host innate immune responses. Increasing evidence indicates that these antiviral factors may have a dual role by directly inhibiting viral replication as well as by sensing and transmitting signals to induce antiviral cytokines. Recent studies have pointed at new, unappreciated mechanisms of viral evasion of host innate protective responses including manipulating the host ubiquitin (Ub) system. Virus-mediated inhibition of antiviral factors by Ub-dependent degradation is emerging as a crucial mechanism for evading the antiviral response. In addition, recent studies have uncovered new mechanisms by which virus-encoded proteins inhibit Ub and Ub-like (Ubl) modification of host proteins involved in innate immune signaling pathways. Here we discuss recent findings and novel strategies that viruses have developed to counteract these early innate antiviral defenses.
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Affiliation(s)
- Ricardo Rajsbaum
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, USA
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, USA
| | - Adolfo García-Sastre
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, USA
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, USA
- Department of Medicine, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, USA
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Rodriguez KR, Horvath CM. Amino acid requirements for MDA5 and LGP2 recognition by paramyxovirus V proteins: a single arginine distinguishes MDA5 from RIG-I. J Virol 2013; 87:2974-8. [PMID: 23269789 PMCID: PMC3571387 DOI: 10.1128/jvi.02843-12] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 12/14/2012] [Indexed: 01/20/2023] Open
Abstract
Paramyxovirus V proteins bind to MDA5 (melanoma differentiation-associated gene 5) and LGP2 (laboratory of genetics and physiology gene 2) but not RIG-I (retinoic acid-inducible gene I). The results demonstrate MDA5 R806 is essential for inhibition by diverse V proteins. Complementary substitution for the analogous RIG-I L714 confers V protein recognition. The analogous LGP2 R455 is required for recognition by measles V protein, but not other V proteins. These findings indicate that paramyxoviruses use a single amino acid to distinguish MDA5 from RIG-I and have evolved distinct contact sites for LGP2 interference.
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Affiliation(s)
- Kenny R Rodriguez
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, USA
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35
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Chinnakannan SK, Nanda SK, Baron MD. Morbillivirus v proteins exhibit multiple mechanisms to block type 1 and type 2 interferon signalling pathways. PLoS One 2013; 8:e57063. [PMID: 23431397 PMCID: PMC3576338 DOI: 10.1371/journal.pone.0057063] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2012] [Accepted: 01/17/2013] [Indexed: 12/20/2022] Open
Abstract
Morbilliviruses form a closely related group of pathogenic viruses which encode three non-structural proteins V, W and C in their P gene. Previous studies with rinderpest virus (RPV) and measles virus (MeV) have demonstrated that these non-structural proteins play a crucial role in blocking type I (IFNα/β) and type II (IFNγ) interferon action, and various mechanisms have been proposed for these effects. We have directly compared four important morbilliviruses, rinderpest (RPV), measles virus (MeV), peste des petits ruminants virus (PPRV) and canine distemper virus (CDV). These viruses and their V proteins could all block type I IFN action. However, the viruses and their V proteins had varying abilities to block type II IFN action. The ability to block type II IFN-induced gene transcription correlated with co-precipitation of STAT1 with the respective V protein, but there was no correlation between co-precipitation of either STAT1 or STAT2 and the abilities of the V proteins to block type I IFN-induced gene transcription or the creation of the antiviral state. Further study revealed that the V proteins of RPV, MeV, PPRV and CDV could all interfere with phosphorylation of the interferon-receptor-associated kinase Tyk2, and the V protein of highly virulent RPV could also block the phosphorylation of another such kinase, Jak1. Co-precipitation studies showed that morbillivirus V proteins all form a complex containing Tyk2 and Jak1. This study highlights the ability of morbillivirus V proteins to target multiple components of the IFN signalling pathways to control both type I and type II IFN action.
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36
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Brunen D, Mesman AW, Geijtenbeek TBH. RIG-I-like receptors and intracellular Toll-like receptors in antiviral immunity. Future Virol 2013. [DOI: 10.2217/fvl.12.119] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Viral recognition by pattern recognition receptors is a crucial step in antiviral immunity. Toll-like receptors (TLRs) and RIG-I-like receptors (RLRs) represent two classes of nucleic acid-sensing pattern recognition receptors that play a major role in inducing an antiviral response. Whereas nucleic acid-recognizing TLRs are transmembrane receptors localized in endosomes, RLRs are distributed within the cytoplasm. Recognition of viral nucleic acid by either class of receptors results in activation of downstream signaling pathways. This eventually induces expression of type I IFN and inflammatory cytokines via activation of the transcription factors IRF3, NF-κB and AP-1. Many viruses, such as the extensively studied family of Paramyxoviridae, have evolved sophisticated mechanisms to evade these responses. This review focuses on the differences between viral recognition, signaling pathways and induction of adaptive immunity evoked by RLRs and intracellular TLRs.
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Affiliation(s)
- Diede Brunen
- Department of Experimental Immunology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Annelies W Mesman
- Department of Experimental Immunology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Teunis BH Geijtenbeek
- Department of Experimental Immunology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands.
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37
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Caignard G, Lucas-Hourani M, Dhondt KP, Labernardière JL, Petit T, Jacob Y, Horvat B, Tangy F, Vidalain PO. The V protein of Tioman virus is incapable of blocking type I interferon signaling in human cells. PLoS One 2013; 8:e53881. [PMID: 23342031 PMCID: PMC3544715 DOI: 10.1371/journal.pone.0053881] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Accepted: 12/04/2012] [Indexed: 12/17/2022] Open
Abstract
The capacity of a virus to cross species barriers is determined by the development of bona fide interactions with cellular components of new hosts, and in particular its ability to block IFN-α/β antiviral signaling. Tioman virus (TioV), a close relative of mumps virus (MuV), has been isolated in giant fruit bats in Southeast Asia. Nipah and Hendra viruses, which are present in the same bat colonies, are highly pathogenic in human. Despite serological evidences of close contacts between TioV and human populations, whether TioV is associated to some human pathology remains undetermined. Here we show that in contrast to the V protein of MuV, the V protein of TioV (TioV-V) hardly interacts with human STAT2, does not degrade STAT1, and cannot block IFN-α/β signaling in human cells. In contrast, TioV-V properly binds to human STAT3 and MDA5, and thus interferes with IL-6 signaling and IFN-β promoter induction in human cells. Because STAT2 binding was previously identified as a host restriction factor for some Paramyxoviridae, we established STAT2 sequence from giant fruit bats, and binding to TioV-V was tested. Surprisingly, TioV-V interaction with STAT2 from giant fruit bats is also extremely weak and barely detectable. Altogether, our observations question the capacity of TioV to appropriately control IFN-α/β signaling in both human and giant fruit bats that are considered as its natural host.
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Affiliation(s)
- Grégory Caignard
- Unité de Génomique Virale et Vaccination, Centre National de la Recherche Scientifique, URA-3015, Virology Department, Institut Pasteur, Paris, France
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Andrejeva J, Norsted H, Habjan M, Thiel V, Goodbourn S, Randall RE. ISG56/IFIT1 is primarily responsible for interferon-induced changes to patterns of parainfluenza virus type 5 transcription and protein synthesis. J Gen Virol 2012; 94:59-68. [PMID: 23052390 PMCID: PMC3542720 DOI: 10.1099/vir.0.046797-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Interferon (IFN) induces an antiviral state in cells that results in alterations of the patterns and levels of parainfluenza virus type 5 (PIV5) transcripts and proteins. This study reports that IFN-stimulated gene 56/IFN-induced protein with tetratricopeptide repeats 1 (ISG56/IFIT1) is primarily responsible for these effects of IFN. It was shown that treating cells with IFN after infection resulted in an increase in virus transcription but an overall decrease in virus protein synthesis. As there was no obvious decrease in the overall levels of cellular protein synthesis in infected cells treated with IFN, these results suggested that ISG56/IFIT1 selectively inhibits the translation of viral mRNAs. This conclusion was supported by in vitro translation studies. Previous work has shown that ISG56/IFIT1 can restrict the replication of viruses lacking a 2′-O-methyltransferase activity, an enzyme that methylates the 2′-hydroxyl group of ribose sugars in the 5′-cap structures of mRNA. However, the data in the current study strongly suggested that PIV5 mRNAs are methylated at the 2′-hydroxyl group and thus that ISG56/IFIT1 selectively inhibits the translation of PIV5 mRNA by some as yet unrecognized mechanism. It was also shown that ISG56/IFIT1 is primarily responsible for the IFN-induced inhibition of PIV5.
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Affiliation(s)
- J Andrejeva
- School of Biology, Centre for Biomolecular Sciences, BMS Building, North Haugh, University of St Andrews, St Andrews, Fife, KY16 9ST, UK
| | - H Norsted
- School of Biology, Centre for Biomolecular Sciences, BMS Building, North Haugh, University of St Andrews, St Andrews, Fife, KY16 9ST, UK
| | - M Habjan
- Kantonal Hospital St Gallen, Institute of Immunobiology, CH-9007 St Gallen, Switzerland
| | - V Thiel
- Kantonal Hospital St Gallen, Institute of Immunobiology, CH-9007 St Gallen, Switzerland
| | - S Goodbourn
- Division of Basic Medical Sciences, St George's, University of London, London SW17 0RE, UK
| | - R E Randall
- School of Biology, Centre for Biomolecular Sciences, BMS Building, North Haugh, University of St Andrews, St Andrews, Fife, KY16 9ST, UK
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40
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O'Shea JJ, Plenge R. JAK and STAT signaling molecules in immunoregulation and immune-mediated disease. Immunity 2012; 36:542-50. [PMID: 22520847 DOI: 10.1016/j.immuni.2012.03.014] [Citation(s) in RCA: 826] [Impact Index Per Article: 68.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Indexed: 12/12/2022]
Abstract
The discovery of the Janus kinase (JAK)-signal transducer and activator of transcripton (STAT) signaling pathway, a landmark in cell biology, provided a simple mechanism for gene regulation that dramatically advanced our understanding of the action of hormones, interferons, colony-stimulating factors, and interleukins. As we learn more about the complexities of immune responses, new insights into the functions of this pathway continue to be revealed, aided by technology that permits genome-wide views. As we celebrate the 20(th) anniversary of the discovery of this paradigm in cell signaling, it is particularly edifying to see how this knowledge has rapidly been translated to human immune disease. Not only have genome-wide association studies demonstrated that this pathway is highly relevant to human autoimmunity, but targeting JAKs is now a reality in immune-mediated disease.
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Affiliation(s)
- John J O'Shea
- Molecular Immunology and Inflammation Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
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41
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Abstract
Interferon cytokine family members shape the immune response to protect the host from both pathologic infections and tumorigenesis. To mediate their physiologic function, interferons evoke a robust and complex signal transduction pathway that leads to the induction of interferon-stimulated genes with both proinflammatory and antiviral functions. Numerous mechanisms exist to tightly regulate the extent and duration of these cellular responses. Among such mechanisms, the post-translational conjugation of ubiquitin polypeptides to protein mediators of interferon signaling has emerged as a crucially important mode of control. In this mini-review, we highlight recent advances in our understanding of these ubiquitin-mediated mechanisms, their exploitation by invading viruses, and their possible utilization for medical intervention.
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Affiliation(s)
- Serge Y Fuchs
- Department of Animal Biology and Mari Lowe Comparative Oncology Center, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104-4539, USA.
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42
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Basler CF. Nipah and hendra virus interactions with the innate immune system. Curr Top Microbiol Immunol 2012; 359:123-52. [PMID: 22491899 DOI: 10.1007/82_2012_209] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Nipah virus and Hendra virus are related, highly pathogenic paramyxoviruses with unusually broad host ranges. Henipaviruses encode several proteins that block innate immune responses, and these are likely to serve as virulence factors. Specfically, four virus-encoded proteins, the phosphoprotein (P), the V protein, the W protein, and the C protein have each been demonstrated to counteract aspects of the interferon (IFN)-α/β response, a key component of the innate immune response to virus infection. The available data indicate that V and W can inhibit the production of IFNα/β in response to various stimuli, while the P, V, and W proteins also block the ability of IFNs to signal and induce an antiviral state in cells. The C protein also inhibits the antiviral effects of IFNα/β by a poorly characterized mechanism. Reverse genetics systems, which allow the generation of recombinant viruses bearing specific mutations, have demonstrated the importance of the viral IFN-antagonists for replication. With these systems in hand, the field is now poised to define how specific viral IFN-antagonist functions influence viral pathogenesis.
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Affiliation(s)
- Christopher F Basler
- Department of Microbiology, Mount Sinai School of Medicine, New York, NY 10029, USA.
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43
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Wang YE, Pernet O, Lee B. Regulation of the nucleocytoplasmic trafficking of viral and cellular proteins by ubiquitin and small ubiquitin-related modifiers. Biol Cell 2011; 104:121-38. [PMID: 22188262 PMCID: PMC3625690 DOI: 10.1111/boc.201100105] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Accepted: 11/22/2011] [Indexed: 12/29/2022]
Abstract
Nucleocytoplasmic trafficking of many cellular proteins is regulated by nuclear import/export signals as well as post-translational modifications such as covalent conjugation of ubiquitin and small ubiquitin-related modifiers (SUMOs). Ubiquitination and SUMOylation are rapid and reversible ways to modulate the intracellular localisation and function of substrate proteins. These pathways have been co-opted by some viruses, which depend on the host cell machinery to transport their proteins in and out of the nucleus. In this review, we will summarise our current knowledge on the ubiquitin/SUMO-regulated nuclear/subnuclear trafficking of cellular proteins and describe examples of viral exploitation of these pathways.
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Affiliation(s)
- Yao E Wang
- Department of Microbiology, Immunology, and Molecular Genetics, UCLA, Los Angeles, CA 90095, USA
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44
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Dortmans JCFM, Koch G, Rottier PJM, Peeters BPH. Virulence of Newcastle disease virus: what is known so far? Vet Res 2011; 42:122. [PMID: 22195547 PMCID: PMC3269386 DOI: 10.1186/1297-9716-42-122] [Citation(s) in RCA: 157] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 12/23/2011] [Indexed: 12/22/2022] Open
Abstract
In the last decade many studies have been performed on the virulence of Newcastle disease virus (NDV). This is mainly due to the development of reverse genetics systems which made it possible to genetically modify NDV and to investigate the contribution of individual genes and genome regions to its virulence. However, the available information is scattered and a comprehensive overview of the factors and conditions determining NDV virulence is lacking. This review summarises, compares and discusses the available literature and shows that virulence of NDV is a complex trait determined by multiple genetic factors.
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Affiliation(s)
- Jos C F M Dortmans
- Central Veterinary Institute of Wageningen UR, PO Box 65, 8200 AB Lelystad, The Netherlands.
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45
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Jiang X, Chen ZJ. The role of ubiquitylation in immune defence and pathogen evasion. Nat Rev Immunol 2011; 12:35-48. [PMID: 22158412 DOI: 10.1038/nri3111] [Citation(s) in RCA: 260] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Ubiquitylation is a widely used post-translational protein modification that regulates many biological processes, including immune responses. The role of ubiquitin in immune regulation was originally uncovered through studies of antigen presentation and the nuclear factor-κB family of transcription factors, which orchestrate host defence against microorganisms. Recent studies have revealed crucial roles of ubiquitylation in many aspects of the immune system, including innate and adaptive immunity and antimicrobial autophagy. In addition, mounting evidence indicates that microbial pathogens exploit the ubiquitin pathway to evade the host immune system. Here, we review recent advances on the role of ubiquitylation in host defence and pathogen evasion.
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Affiliation(s)
- Xiaomo Jiang
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9148, USA
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46
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Norovirus regulation of the innate immune response and apoptosis occurs via the product of the alternative open reading frame 4. PLoS Pathog 2011; 7:e1002413. [PMID: 22174679 PMCID: PMC3234229 DOI: 10.1371/journal.ppat.1002413] [Citation(s) in RCA: 177] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Accepted: 10/12/2011] [Indexed: 12/25/2022] Open
Abstract
Small RNA viruses have evolved many mechanisms to increase the capacity of their short genomes. Here we describe the identification and characterization of a novel open reading frame (ORF4) encoded by the murine norovirus (MNV) subgenomic RNA, in an alternative reading frame overlapping the VP1 coding region. ORF4 is translated during virus infection and the resultant protein localizes predominantly to the mitochondria. Using reverse genetics we demonstrated that expression of ORF4 is not required for virus replication in tissue culture but its loss results in a fitness cost since viruses lacking the ability to express ORF4 restore expression upon repeated passage in tissue culture. Functional analysis indicated that the protein produced from ORF4 antagonizes the innate immune response to infection by delaying the upregulation of a number of cellular genes activated by the innate pathway, including IFN-Beta. Apoptosis in the RAW264.7 macrophage cell line was also increased during virus infection in the absence of ORF4 expression. In vivo analysis of the WT and mutant virus lacking the ability to express ORF4 demonstrated an important role for ORF4 expression in infection and virulence. STAT1-/- mice infected with a virus lacking the ability to express ORF4 showed a delay in the onset of clinical signs when compared to mice infected with WT virus. Quantitative PCR and histopathological analysis of samples from these infected mice demonstrated that infection with a virus not expressing ORF4 results in a delayed infection in this system. In light of these findings we propose the name virulence factor 1, VF1 for this protein. The identification of VF1 represents the first characterization of an alternative open reading frame protein for the calicivirus family. The immune regulatory function of the MNV VF1 protein provide important perspectives for future research into norovirus biology and pathogenesis. This report describes the identification and characterization of a novel protein of unknown function encoded by a mouse virus genetically similar to human noroviruses. This gene is unique to the mouse virus and occupies the same part of the genome that codes for the major capsid protein. The protein that we have described as virulence factor 1 (VF1) is found in all murine norovirus isolates, absent in all human strains but is indeed expressed during infection. Its expression enables MNV-1 to establish efficient infection of its natural host through interference with interferon-mediated response pathways and apoptosis. Our data would indicate that the VF1 protein is multi-functional with an ability to modulate the host's response to infection. Murine noroviruses are frequently used firstly as a model to study human norovirus replication and pathogenesis, studies hampered by their inability to replicate in cell culture. Secondly, persistent infection of laboratory animals with murine norovirus may affect other models of disease using experimental mice. The role of VF1 in infection and pathology in the differential outcome of infection is the source of continued research in our laboratory.
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47
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Andrus L, Marukian S, Jones CT, Catanese MT, Sheahan TP, Schoggins JW, Barry WT, Dustin LB, Trehan K, Ploss A, Bhatia SN, Rice CM. Expression of paramyxovirus V proteins promotes replication and spread of hepatitis C virus in cultures of primary human fetal liver cells. Hepatology 2011; 54:1901-12. [PMID: 22144107 PMCID: PMC3233237 DOI: 10.1002/hep.24557] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Accepted: 07/01/2011] [Indexed: 12/11/2022]
Abstract
UNLABELLED Here we demonstrate that primary cultures of human fetal liver cells (HFLC) reliably support infection with laboratory strains of hepatitis C virus (HCV), although levels of virus replication vary significantly between different donor cell preparations and frequently decline in a manner suggestive of active viral clearance. To investigate possible contributions of the interferon (IFN) system to control HCV infection in HFLC, we exploited the well-characterized ability of paramyxovirus (PMV) V proteins to counteract both IFN induction and antiviral signaling. The V proteins of measles virus (MV) and parainfluenza virus 5 (PIV5) were introduced into HFLC using lentiviral vectors encoding a fluorescent reporter for visualization of HCV-infected cells. V protein-transduced HFLC supported enhanced (10 to 100-fold) levels of HCV infection relative to untransduced or control vector-transduced HFLC. Infection was assessed by measurement of virus-driven luciferase, by assays for infectious HCV and viral RNA, and by direct visualization of HCV-infected hepatocytes. Live cell imaging between 48 and 119 hours postinfection demonstrated little or no spread of infection in the absence of PMV V protein expression. In contrast, V protein-transduced HFLC showed numerous HCV infection events. V protein expression efficiently antagonized the HCV-inhibitory effects of added IFNs in HFLC. In addition, induction of the type III IFN, IL29, following acute HCV infection was inhibited in V protein-transduced cultures. CONCLUSION These studies suggest that the cellular IFN response plays a significant role in limiting the spread of HCV infection in primary hepatocyte cultures. Strategies aimed at dampening this response may be key to further development of robust HCV culture systems, enabling studies of virus pathogenicity and the mechanisms by which HCV spreads in its natural host cell population.
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Affiliation(s)
- Linda Andrus
- Center for the Study of Hepatitis C, Laboratory of Virology and Infectious Diseases, The Rockefeller University, New York, NY 10021, USA.
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48
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Phillips JE, Jackwood MW, McKinley ET, Thor SW, Hilt DA, Acevedol ND, Williams SM, Kissinger JC, Paterson AH, Robertson JS, Lemke C. Changes in nonstructural protein 3 are associated with attenuation in avian coronavirus infectious bronchitis virus. Virus Genes 2011; 44:63-74. [PMID: 21909766 PMCID: PMC7089577 DOI: 10.1007/s11262-011-0668-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Accepted: 08/25/2011] [Indexed: 01/22/2023]
Abstract
Full-length genome sequencing of pathogenic and attenuated (for chickens) avian coronavirus infectious bronchitis virus (IBV) strains of the same serotype was conducted to identify genetic differences between the pathotypes. Analysis of the consensus full-length genome for three different IBV serotypes (Ark, GA98, and Mass41) showed that passage in embryonated eggs, to attenuate the viruses for chickens, resulted in 34.75–43.66% of all the amino acid changes occurring in nsp 3 within a virus type, whereas changes in the spike glycoprotein, thought to be the most variable protein in IBV, ranged from 5.8 to 13.4% of all changes. The attenuated viruses did not cause any clinical signs of disease and had lower replication rates than the pathogenic viruses of the same serotype in chickens. However, both attenuated and pathogenic viruses of the same serotype replicated similarly in embryonated eggs, suggesting that mutations in nsp 3, which is involved in replication of the virus, might play an important role in the reduced replication observed in chickens leading to the attenuated phenotype.
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Affiliation(s)
- J. E. Phillips
- Department of Population Health, College of Veterinary Medicine, University of Georgia, 953 College Station Road, Athens, GA 30602 USA
| | - M. W. Jackwood
- Department of Population Health, College of Veterinary Medicine, University of Georgia, 953 College Station Road, Athens, GA 30602 USA
| | - E. T. McKinley
- Present Address: Southeast Poultry Research Laboratory, USDA, Agricultural Research Service, 934 College Station Road, Athens, GA 30605 USA
| | - S. W. Thor
- Department of Population Health, College of Veterinary Medicine, University of Georgia, 953 College Station Road, Athens, GA 30602 USA
| | - D. A. Hilt
- Department of Population Health, College of Veterinary Medicine, University of Georgia, 953 College Station Road, Athens, GA 30602 USA
| | - N. D. Acevedol
- Present Address: Veterinary Medical Center of Long Island, 75 Sunrise Highway, West Islip, NY 11795 USA
| | - S. M. Williams
- Department of Population Health, College of Veterinary Medicine, University of Georgia, 953 College Station Road, Athens, GA 30602 USA
| | - J. C. Kissinger
- Department of Genetics, Center for Tropical and Emerging Global Diseases, University of Georgia, 500 D. W. Brooks Drive, Athens, GA 30602 USA
| | - A. H. Paterson
- Plant Genome Mapping Laboratory, Departments of Crop and Soil Sciences, Plant Biology, and Genetics, University of Georgia, 111 Riverbend Road, Athens, GA 30602 USA
| | - J. S. Robertson
- Plant Genome Mapping Laboratory, Departments of Crop and Soil Sciences, Plant Biology, and Genetics, University of Georgia, 111 Riverbend Road, Athens, GA 30602 USA
| | - C. Lemke
- Plant Genome Mapping Laboratory, Departments of Crop and Soil Sciences, Plant Biology, and Genetics, University of Georgia, 111 Riverbend Road, Athens, GA 30602 USA
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Gerlier D, Lyles DS. Interplay between innate immunity and negative-strand RNA viruses: towards a rational model. Microbiol Mol Biol Rev 2011; 75:468-90, second page of table of contents. [PMID: 21885681 PMCID: PMC3165544 DOI: 10.1128/mmbr.00007-11] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The discovery of a new class of cytosolic receptors recognizing viral RNA, called the RIG-like receptors (RLRs), has revolutionized our understanding of the interplay between viruses and host cells. A tremendous amount of work has been accumulating to decipher the RNA moieties required for an RLR agonist, the signal transduction pathway leading to activation of the innate immunity orchestrated by type I interferon (IFN), the cellular and viral regulators of this pathway, and the viral inhibitors of the innate immune response. Previous reviews have focused on the RLR signaling pathway and on the negative regulation of the interferon response by viral proteins. The focus of this review is to put this knowledge in the context of the virus replication cycle within a cell. Likewise, there has been an expansion of knowledge about the role of innate immunity in the pathophysiology of viral infection. As a consequence, some discrepancies have arisen between the current models of cell-intrinsic innate immunity and current knowledge of virus biology. This holds particularly true for the nonsegmented negative-strand viruses (Mononegavirales), which paradoxically have been largely used to build presently available models. The aim of this review is to bridge the gap between the virology and innate immunity to favor the rational building of a relevant model(s) describing the interplay between Mononegavirales and the innate immune system.
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Affiliation(s)
- Denis Gerlier
- INSERM U758, CERVI, 21 avenue Tony Garnier, 69007 Lyon, France.
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50
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Genomic analysis of four human metapneumovirus prototypes. Virus Res 2011; 160:200-5. [PMID: 21740936 DOI: 10.1016/j.virusres.2011.06.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Revised: 06/18/2011] [Accepted: 06/21/2011] [Indexed: 11/22/2022]
Abstract
Human metapneumovirus (HMPV) is an important cause of acute respiratory illness in children. We determined the complete genome sequence of four strains of HMPV representing each of the four lineages. These sequences were compared with published HMPV genome sequences. Most genes were conserved between the genetic lineages (79.5-99.6%), though nucleotide diversity was greater than amino acid diversity, suggesting functional constraints on mutation. However, the SH and G open reading frames were more variable (mean 76.4% and 59.0% aa identity, respectively), with mostly nonsynonymous changes, suggesting selective pressure on the SH and G proteins. Gene-start regions were largely conserved between genes and viruses, while gene-end sequences were conserved between viruses but not between genes. The SH-G and G-L intergenic regions were extremely long (∼200 nt) and have no defined function, yet were highly conserved within major groups. These findings highlight broadly conserved regions of the HMPV genome and suggest unidentified biological roles for SH and G.
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