1
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Pallavi R, Gatti E, Durfort T, Stendardo M, Ravasio R, Leonardi T, Falvo P, Duso BA, Punzi S, Xieraili A, Polazzi A, Verrelli D, Trastulli D, Ronzoni S, Frascolla S, Perticari G, Elgendy M, Varasi M, Colombo E, Giorgio M, Lanfrancone L, Minucci S, Mazzarella L, Pelicci PG. Caloric restriction leads to druggable LSD1-dependent cancer stem cells expansion. Nat Commun 2024; 15:828. [PMID: 38280853 PMCID: PMC10821871 DOI: 10.1038/s41467-023-44348-y] [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: 08/07/2023] [Accepted: 12/10/2023] [Indexed: 01/29/2024] Open
Abstract
Caloric Restriction (CR) has established anti-cancer effects, but its clinical relevance and molecular mechanism remain largely undefined. Here, we investigate CR's impact on several mouse models of Acute Myeloid Leukemias, including Acute Promyelocytic Leukemia, a subtype strongly affected by obesity. After an initial marked anti-tumor effect, lethal disease invariably re-emerges. Initially, CR leads to cell-cycle restriction, apoptosis, and inhibition of TOR and insulin/IGF1 signaling. The relapse, instead, is associated with the non-genetic selection of Leukemia Initiating Cells and the downregulation of double-stranded RNA (dsRNA) sensing and Interferon (IFN) signaling genes. The CR-induced adaptive phenotype is highly sensitive to pharmacological or genetic ablation of LSD1, a lysine demethylase regulating both stem cells and dsRNA/ IFN signaling. CR + LSD1 inhibition leads to the re-activation of dsRNA/IFN signaling, massive RNASEL-dependent apoptosis, and complete leukemia eradication in ~90% of mice. Importantly, CR-LSD1 interaction can be modeled in vivo and in vitro by combining LSD1 ablation with pharmacological inhibitors of insulin/IGF1 or dual PI3K/MEK blockade. Mechanistically, insulin/IGF1 inhibition sensitizes blasts to LSD1-induced death by inhibiting the anti-apoptotic factor CFLAR. CR and LSD1 inhibition also synergize in patient-derived AML and triple-negative breast cancer xenografts. Our data provide a rationale for epi-metabolic pharmacologic combinations across multiple tumors.
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Affiliation(s)
- Rani Pallavi
- Department of Experimental Oncology, IEO European Institute of Oncology IRCCS, Milan, Italy
| | - Elena Gatti
- Department of Experimental Oncology, IEO European Institute of Oncology IRCCS, Milan, Italy
| | - Tiphanie Durfort
- Department of Experimental Oncology, IEO European Institute of Oncology IRCCS, Milan, Italy
| | - Massimo Stendardo
- Department of Experimental Oncology, IEO European Institute of Oncology IRCCS, Milan, Italy
| | - Roberto Ravasio
- Department of Experimental Oncology, IEO European Institute of Oncology IRCCS, Milan, Italy
| | - Tommaso Leonardi
- Center for Genomic Science of IIT@SEMM, Fondazione Istituto Italiano di Tecnologia, Milan, Italy
| | - Paolo Falvo
- Department of Experimental Oncology, IEO European Institute of Oncology IRCCS, Milan, Italy
| | - Bruno Achutti Duso
- Department of Experimental Oncology, IEO European Institute of Oncology IRCCS, Milan, Italy
| | - Simona Punzi
- Department of Experimental Oncology, IEO European Institute of Oncology IRCCS, Milan, Italy
| | - Aobuli Xieraili
- Department of Experimental Oncology, IEO European Institute of Oncology IRCCS, Milan, Italy
| | - Andrea Polazzi
- Department of Experimental Oncology, IEO European Institute of Oncology IRCCS, Milan, Italy
| | - Doriana Verrelli
- Department of Experimental Oncology, IEO European Institute of Oncology IRCCS, Milan, Italy
| | - Deborah Trastulli
- Department of Experimental Oncology, IEO European Institute of Oncology IRCCS, Milan, Italy
| | - Simona Ronzoni
- Department of Experimental Oncology, IEO European Institute of Oncology IRCCS, Milan, Italy
| | - Simone Frascolla
- Department of Experimental Oncology, IEO European Institute of Oncology IRCCS, Milan, Italy
| | - Giulia Perticari
- Department of Experimental Oncology, IEO European Institute of Oncology IRCCS, Milan, Italy
| | - Mohamed Elgendy
- Department of Experimental Oncology, IEO European Institute of Oncology IRCCS, Milan, Italy
- Institute for Clinical Chemistry and Laboratory Medicine, University Hospital and Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
- Medical Clinic I, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
- Mildred-Scheel Early Career Center, National Center for Tumor Diseases Dresden (NCT/UCC) University Hospital and Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
- Cancer Cell Biology, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, CZ-14220, Czech Republic
| | - Mario Varasi
- IFOM ETS - The AIRC Institute of Molecular Oncology, Milan, Italy
| | - Emanuela Colombo
- Department of Experimental Oncology, IEO European Institute of Oncology IRCCS, Milan, Italy
- Department of Hemato-Oncology, Universita' Statale di Milano, Milan, Italy
| | - Marco Giorgio
- Department of Experimental Oncology, IEO European Institute of Oncology IRCCS, Milan, Italy
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Luisa Lanfrancone
- Department of Experimental Oncology, IEO European Institute of Oncology IRCCS, Milan, Italy
| | - Saverio Minucci
- Department of Experimental Oncology, IEO European Institute of Oncology IRCCS, Milan, Italy
- Department of Hemato-Oncology, Universita' Statale di Milano, Milan, Italy
| | - Luca Mazzarella
- Department of Experimental Oncology, IEO European Institute of Oncology IRCCS, Milan, Italy.
| | - Pier Giuseppe Pelicci
- Department of Experimental Oncology, IEO European Institute of Oncology IRCCS, Milan, Italy.
- Department of Hemato-Oncology, Universita' Statale di Milano, Milan, Italy.
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Jadaa N, Aldor N, Jenik K, Oberhoffner S, Butkowsky C, Tran A, Lewis A, DeWitte-Orr SJ, Poynter S. Evaluating Cationic Nanoparticles as Carriers of Antiviral Nucleic Acids. Methods Mol Biol 2024; 2813:309-320. [PMID: 38888786 DOI: 10.1007/978-1-0716-3890-3_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
Nanoparticle carriers enable the multivalent delivery of nucleic acids to cells and protect them from degradation. In this chapter, we present a comprehensive overview of four methodologies: electrophoretic mobility shift assay (EMSA), alamarBlue/CFDA-AM cell viability dyes, fluorescence microscopy, and antiviral assays, which collectively are tools to explore interactions between nucleic acids and nanoparticles, and their biological efficacy. These assays provide insights into binding potential, cytotoxicity, and antiviral efficacy of nucleic acid-based nanoparticle treatments furthering the development of effective antiviral therapeutics.
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Affiliation(s)
| | | | | | | | | | - Andy Tran
- Wilfrid Laurier University, Waterloo, ON, Canada
| | - Aaron Lewis
- Wilfrid Laurier University, Waterloo, ON, Canada
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3
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Schindewolf C, Lokugamage K, Vu MN, Johnson BA, Scharton D, Plante JA, Kalveram B, Crocquet-Valdes PA, Sotcheff S, Jaworski E, Alvarado RE, Debbink K, Daugherty MD, Weaver SC, Routh AL, Walker DH, Plante KS, Menachery VD. SARS-CoV-2 Uses Nonstructural Protein 16 To Evade Restriction by IFIT1 and IFIT3. J Virol 2023; 97:e0153222. [PMID: 36722972 PMCID: PMC9973020 DOI: 10.1128/jvi.01532-22] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 01/13/2023] [Indexed: 02/02/2023] Open
Abstract
Understanding the molecular basis of innate immune evasion by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an important consideration for designing the next wave of therapeutics. Here, we investigate the role of the nonstructural protein 16 (NSP16) of SARS-CoV-2 in infection and pathogenesis. NSP16, a ribonucleoside 2'-O-methyltransferase (MTase), catalyzes the transfer of a methyl group to mRNA as part of the capping process. Based on observations with other CoVs, we hypothesized that NSP16 2'-O-MTase function protects SARS-CoV-2 from cap-sensing host restriction. Therefore, we engineered SARS-CoV-2 with a mutation that disrupts a conserved residue in the active site of NSP16. We subsequently show that this mutant is attenuated both in vitro and in vivo, using a hamster model of SARS-CoV-2 infection. Mechanistically, we confirm that the NSP16 mutant is more sensitive than wild-type SARS-CoV-2 to type I interferon (IFN-I) in vitro. Furthermore, silencing IFIT1 or IFIT3, IFN-stimulated genes that sense a lack of 2'-O-methylation, partially restores fitness to the NSP16 mutant. Finally, we demonstrate that sinefungin, an MTase inhibitor that binds the catalytic site of NSP16, sensitizes wild-type SARS-CoV-2 to IFN-I treatment and attenuates viral replication. Overall, our findings highlight the importance of SARS-CoV-2 NSP16 in evading host innate immunity and suggest a target for future antiviral therapies. IMPORTANCE Similar to other coronaviruses, disruption of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) NSP16 function attenuates viral replication in a type I interferon-dependent manner. In vivo, our results show reduced disease and viral replication at late times in the hamster lung, but an earlier titer deficit for the NSP16 mutant (dNSP16) in the upper airway. In addition, our results confirm a role for IFIT1 but also demonstrate the necessity of IFIT3 in mediating dNSP16 attenuation. Finally, we show that targeting NSP16 activity with a 2'-O-methyltransferase inhibitor in combination with type I interferon offers a novel avenue for antiviral development.
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Affiliation(s)
- Craig Schindewolf
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, USA
| | - Kumari Lokugamage
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Michelle N. Vu
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Bryan A. Johnson
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Dionna Scharton
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
- World Reference Center for Emerging Viruses and Arboviruses, University of Texas Medical Branch, Galveston, Texas, USA
| | - Jessica A. Plante
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
- World Reference Center for Emerging Viruses and Arboviruses, University of Texas Medical Branch, Galveston, Texas, USA
| | - Birte Kalveram
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas, USA
| | | | - Stephanea Sotcheff
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Elizabeth Jaworski
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas, USA
| | - Rojelio E. Alvarado
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
- Institute for Translational Sciences, University of Texas Medical Branch, Galveston, Texas, USA
| | - Kari Debbink
- Department of Microbiology and Immunology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Matthew D. Daugherty
- Department of Molecular Biology, University of California, San Diego, California, USA
| | - Scott C. Weaver
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, USA
- World Reference Center for Emerging Viruses and Arboviruses, University of Texas Medical Branch, Galveston, Texas, USA
| | - Andrew L. Routh
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, USA
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas, USA
| | - David H. Walker
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, USA
- Center for Biodefense and Emerging Infectious Disease, University of Texas Medical Branch, Galveston, Texas, USA
| | - Kenneth S. Plante
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, USA
- World Reference Center for Emerging Viruses and Arboviruses, University of Texas Medical Branch, Galveston, Texas, USA
| | - Vineet D. Menachery
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, USA
- World Reference Center for Emerging Viruses and Arboviruses, University of Texas Medical Branch, Galveston, Texas, USA
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Differential Cellular Sensing of Fusion from within and Fusion from without during Virus Infection. Viruses 2023; 15:v15020301. [PMID: 36851515 PMCID: PMC9962872 DOI: 10.3390/v15020301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 01/18/2023] [Accepted: 01/19/2023] [Indexed: 01/24/2023] Open
Abstract
The physical entry of virus particles into cells triggers an innate immune response that is dependent on both calcium and nucleic acid sensors, with particles containing RNA or DNA genomes detected by RNA or DNA sensors, respectively. While membrane fusion in the absence of viral nucleic acid causes an innate immune response that is dependent on calcium, the involvement of nucleic acid sensors is poorly understood. Here, we used lipoplexes containing purified reovirus p14 fusion protein as a model of exogenous or fusion from without and a cell line expressing inducible p14 protein as a model of endogenous or fusion from within to examine cellular membrane fusion sensing events. We show that the cellular response to membrane fusion in both models is dependent on calcium, IRF3 and IFN. The method of sensing fusion, however, differs between fusion from without and fusion from within. Exogenous p14 lipoplexes are detected by RIG-I-like RNA sensors, whereas fusion by endogenous p14 requires both RIG-I and STING to trigger an IFN response. The source of nucleic acid that is sensed appears to be cellular in origin. Future studies will investigate the source of endogenous nucleic acids recognized following membrane fusion events.
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Li X, Liu X, Lu W, Yin X, An S. Application progress of plant-mediated RNAi in pest control. Front Bioeng Biotechnol 2022; 10:963026. [PMID: 36003536 PMCID: PMC9393288 DOI: 10.3389/fbioe.2022.963026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 07/11/2022] [Indexed: 01/09/2023] Open
Abstract
RNA interference (RNAi)-based biopesticides are novel biologic products, developed using RNAi principles. They are engineered to target genes of agricultural diseases, insects, and weeds, interfering with their target gene expression so as to hinder their growth and alleviate their damaging effects on crops. RNAi-based biopesticides are broadly classified into resistant plant-based plant-incorporated protectants (PIPs) and non-plant-incorporated protectants. PIP RNAi-based biopesticides are novel biopesticides that combine the advantages of RNAi and resistant transgenic crops. Such RNAi-based biopesticides are developed through nuclear or plastid transformation to breed resistant plants, i.e., dsRNA-expressing transgenic plants. The dsRNA of target genes is expressed in the plant cell, with pest and disease control being achieved through plant-target organism interactions. Here, we review the action mechanism and strategies of RNAi for pest management, the development of RNAi-based transgenic plant, and the current status and advantages of deploying these products for pest control, as well as the future research directions and problems in production and commercialization. Overall, this study aims to elucidate the current development status of RNAi-based biopesticides and provide guidelines for future research.
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6
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Semple SL, Au SKW, Jacob RA, Mossman KL, DeWitte-Orr SJ. Discovery and Use of Long dsRNA Mediated RNA Interference to Stimulate Antiviral Protection in Interferon Competent Mammalian Cells. Front Immunol 2022; 13:859749. [PMID: 35603190 PMCID: PMC9120774 DOI: 10.3389/fimmu.2022.859749] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 04/04/2022] [Indexed: 12/20/2022] Open
Abstract
In invertebrate cells, RNA interference (RNAi) acts as a powerful immune defense that stimulates viral gene knockdown thereby preventing infection. With this pathway, virally produced long dsRNA (dsRNA) is cleaved into short interfering RNA (siRNA) by Dicer and loaded into the RNA-induced silencing complex (RISC) which can then destroy/disrupt complementary viral mRNA sequences. Comparatively, in mammalian cells it is believed that the type I interferon (IFN) pathway is the cornerstone of the innate antiviral response. In these cells, dsRNA acts as a potent inducer of the IFN system, which is dependent on dsRNA length, but not sequence, to stimulate an antiviral state. Although the cellular machinery for RNAi is intact and functioning in mammalian cells, its role to trigger an antiviral response using long dsRNA (dsRNAi) remains controversial. Here we show that dsRNAi is not only functional but has a significant antiviral effect in IFN competent mammalian cells. We found that pre-soaking mammalian cells with concentrations of sequence specific dsRNA too low to induce IFN production could significantly inhibit vesicular stomatitis virus expressing green fluorescent protein (VSV-GFP), and the human coronaviruses (CoV) HCoV-229E and SARS-CoV-2 replication. This phenomenon was shown to be dependent on dsRNA length, was comparable in effect to transfected siRNAs, and could knockdown multiple sequences at once. Additionally, knockout cell lines revealed that functional Dicer was required for viral inhibition, revealing that the RNAi pathway was indeed responsible. These results provide the first evidence that soaking with gene-specific long dsRNA can generate viral knockdown in mammalian cells. We believe that this novel discovery provides an explanation as to why the mammalian lineage retained its RNAi machinery and why vertebrate viruses have evolved methods to suppress RNAi. Furthermore, demonstrating RNAi below the threshold of IFN induction has uses as a novel therapeutic platform, both antiviral and gene targeting in nature.
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Affiliation(s)
- Shawna L. Semple
- Department of Health Sciences, Wilfrid Laurier University, Waterloo, ON, Canada
| | - Sarah K. W. Au
- Department of Health Sciences, Wilfrid Laurier University, Waterloo, ON, Canada
| | - Rajesh A. Jacob
- Department of Medicine, McMaster University, Hamilton, ON, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada
- McMaster Immunology Research Centre, McMaster University, Hamilton, ON, Canada
| | - Karen L. Mossman
- Department of Medicine, McMaster University, Hamilton, ON, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada
- McMaster Immunology Research Centre, McMaster University, Hamilton, ON, Canada
| | - Stephanie J. DeWitte-Orr
- Department of Health Sciences, Wilfrid Laurier University, Waterloo, ON, Canada
- *Correspondence: Stephanie J. DeWitte-Orr,
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PRMT7 ablation stimulates anti-tumor immunity and sensitizes melanoma to immune checkpoint blockade. Cell Rep 2022; 38:110582. [PMID: 35354055 PMCID: PMC9838175 DOI: 10.1016/j.celrep.2022.110582] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 01/08/2022] [Accepted: 03/07/2022] [Indexed: 01/17/2023] Open
Abstract
Despite the success of immune checkpoint inhibitor (ICI) therapy for cancer, resistance and relapse are frequent. Combination therapies are expected to enhance response rates and overcome this resistance. Herein, we report that combining PRMT7 inhibition with ICI therapy induces a strong anti-tumor T cell immunity and restrains tumor growth in vivo by increasing immune cell infiltration. PRMT7-deficient B16.F10 melanoma exhibits increased expression of genes in the interferon pathway, antigen presentation, and chemokine signaling. PRMT7 deficiency or inhibition with SGC3027 in B16.F10 melanoma results in reduced DNMT expression, loss of DNA methylation in the regulatory regions of endogenous retroviral elements (ERVs) causing their increased expression. PRMT7-deficient cells increase RIG-I and MDA5 expression with a reduction in the H4R3me2s repressive histone mark at their gene promoters. Our findings identify PRMT7 as a regulatory checkpoint for RIG-I, MDA5, and their ERV-double-stranded RNA (dsRNA) ligands, facilitating immune escape and anti-tumor T cell immunity to restrain tumor growth.
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8
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Störk T, de le Roi M, Haverkamp AK, Jesse ST, Peters M, Fast C, Gregor KM, Könenkamp L, Steffen I, Ludlow M, Beineke A, Hansmann F, Wohlsein P, Osterhaus ADME, Baumgärtner W. Analysis of avian Usutu virus infections in Germany from 2011 to 2018 with focus on dsRNA detection to demonstrate viral infections. Sci Rep 2021; 11:24191. [PMID: 34921222 PMCID: PMC8683490 DOI: 10.1038/s41598-021-03638-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 12/07/2021] [Indexed: 11/11/2022] Open
Abstract
Usutu virus (USUV) is a zoonotic arbovirus causing avian mass mortalities. The first outbreak in North-Western Germany occurred in 2018. This retrospective analysis focused on combining virological and pathological findings in birds and immunohistochemistry. 25 common blackbirds, one great grey owl, and one kingfisher collected from 2011 to 2018 and positive for USUV by qRT-PCR were investigated. Macroscopically, most USUV infected birds showed splenomegaly and hepatomegaly. Histopathological lesions included necrosis and lymphohistiocytic inflammation within spleen, Bursa fabricii, liver, heart, brain, lung and intestine. Immunohistochemistry revealed USUV antigen positive cells in heart, spleen, pancreas, lung, brain, proventriculus/gizzard, Bursa fabricii, kidney, intestine, skeletal muscle, and liver. Analysis of viral genome allocated the virus to Europe 3 or Africa 2 lineage. This study investigated whether immunohistochemical detection of double-stranded ribonucleic acid (dsRNA) serves as an alternative tool to detect viral intermediates. Tissue samples of six animals with confirmed USUV infection by qRT-PCR but lacking viral antigen in liver and spleen, were further examined immunohistochemically. Two animals exhibited a positive signal for dsRNA. This could indicate either an early state of infection without sufficient formation of virus translation products, occurrence of another concurrent virus infection or endogenous dsRNA not related to infectious pathogens and should be investigated in more detail in future studies.
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McGarry N, Murray CL, Garvey S, Wilkinson A, Tortorelli L, Ryan L, Hayden L, Healy D, Griffin EW, Hennessy E, Arumugam M, Skelly DT, Mitchell KJ, Cunningham C. Double stranded RNA drives anti-viral innate immune responses, sickness behavior and cognitive dysfunction dependent on dsRNA length, IFNAR1 expression and age. Brain Behav Immun 2021; 95:413-428. [PMID: 33892139 PMCID: PMC8447494 DOI: 10.1016/j.bbi.2021.04.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 04/08/2021] [Accepted: 04/18/2021] [Indexed: 02/08/2023] Open
Abstract
Double stranded RNA is generated during viral replication. The synthetic analogue poly I:C is frequently used to mimic anti-viral innate immune responses in models of psychiatric and neurodegenerative disorders including schizophrenia, autism, Parkinson's disease and Alzheimer's disease. Many studies perform limited analysis of innate immunity despite these responses potentially differing as a function of dsRNA molecular weight and age. Therefore fundamental questions relevant to impacts of systemic viral infection on brain function and integrity remain. Here, we studied innate immune-inducing properties of poly I:C preparations of different lengths and responses in adult and aged mice. High molecular weight (HMW) poly I:C (1-6 kb, 12 mg/kg) produced more robust sickness behavior and more robust IL-6, IFN-I and TNF-α responses than poly I:C of < 500 bases (low MW) preparations. This was partly overcome with higher doses of LMW (up to 80 mg/kg), but neither circulating IFNβ nor brain transcription of Irf7 were significantly induced by LMW poly I:C, despite brain Ifnb transcription, suggesting that brain IFN-dependent gene expression is predominantly triggered by circulating IFNβ binding of IFNAR1. In aged animals, poly I:C induced exaggerated IL-6, IL-1β and IFN-I in the plasma and similar exaggerated brain cytokine responses. This was associated with acute working memory deficits selectively in aged mice. Thus, we demonstrate dsRNA length-, IFNAR1- and age-dependent effects on anti-viral inflammation and cognitive function. The data have implications for CNS symptoms of acute systemic viral infection such as those with SARS-CoV-2 and for models of maternal immune activation.
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Affiliation(s)
- Niamh McGarry
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute & Trinity College Institute of Neuroscience, Trinity College Dublin, Ireland
| | - Carol L Murray
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute & Trinity College Institute of Neuroscience, Trinity College Dublin, Ireland
| | - Sean Garvey
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute & Trinity College Institute of Neuroscience, Trinity College Dublin, Ireland
| | - Abigail Wilkinson
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute & Trinity College Institute of Neuroscience, Trinity College Dublin, Ireland
| | - Lucas Tortorelli
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute & Trinity College Institute of Neuroscience, Trinity College Dublin, Ireland
| | - Lucy Ryan
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute & Trinity College Institute of Neuroscience, Trinity College Dublin, Ireland
| | - Lorna Hayden
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute & Trinity College Institute of Neuroscience, Trinity College Dublin, Ireland
| | - Daire Healy
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute & Trinity College Institute of Neuroscience, Trinity College Dublin, Ireland
| | - Eadaoin W Griffin
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute & Trinity College Institute of Neuroscience, Trinity College Dublin, Ireland
| | - Edel Hennessy
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute & Trinity College Institute of Neuroscience, Trinity College Dublin, Ireland
| | - Malathy Arumugam
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute & Trinity College Institute of Neuroscience, Trinity College Dublin, Ireland
| | - Donal T Skelly
- Nuffield Department of Clinical Neurosciences, University of Oxford, United Kingdom
| | - Kevin J Mitchell
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - Colm Cunningham
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute & Trinity College Institute of Neuroscience, Trinity College Dublin, Ireland.
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10
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Mcgarry N, Murray CL, Garvey S, Wilkinson A, Tortorelli L, Ryan L, Hayden L, Healy D, Griffin EW, Hennessy E, Arumugam M, Skelly DT, Mitchell KJ, Cunningham C. Double stranded RNA drives innate immune responses, sickness behavior and cognitive impairment dependent on dsRNA length, IFNAR1 expression and age.. [PMID: 33442686 PMCID: PMC7805443 DOI: 10.1101/2021.01.09.426034] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Double stranded RNA is generated during viral replication. The synthetic analogue poly I:C is frequently used to mimic anti-viral innate immune responses in models of psychiatric and neurodegenerative disorders including schizophrenia, autism, Parkinson’s disease and Alzheimer’s disease. Many studies perform limited analysis of innate immunity despite these responses potentially differing as a function of dsRNA molecular weight and age. Therefore fundamental questions relevant to impacts of systemic viral infection on brain function and integrity remain. Here, we studied innate immune-inducing properties of poly I:C preparations of different lengths and responses in adult and aged mice. High molecular weight (HMW) poly I:C (1–6kb, 12 mg/kg) produced more robust sickness behavior and more robust IL-6, IFN-I and TNFα responses than poly I:C of <500 bases (low MW) preparations. This was partly overcome with higher doses of LMW (up to 80 mg/kg), but neither circulating IFNβ nor brain transcription of Irf7 were significantly induced by LMW poly I:C, despite brain Ifnb transcription, suggesting that brain IFN-dependent gene expression is predominantly triggered by circulating IFNβ binding of IFNAR1. In aged animals, poly I:C induced exaggerated IL-6, IL-1β and IFN-I in the plasma and similar exaggerated brain cytokine responses. This was associated with acute working memory deficits selectively in aged mice. Thus, we demonstrate dsRNA length-, IFNAR1- and age-dependent effects on anti-viral inflammation and cognitive function. The data have implications for CNS symptoms of acute systemic viral infection such as those with SARS-CoV-2 and for models of maternal immune activation.
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11
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Vats A, Gautam D, Maharana J, Singh Chera J, Kumar S, Rout PK, Werling D, De S. Poly I:C stimulation in-vitro as a marker for an antiviral response in different cell types generated from Buffalo (Bubalus bubalis). Mol Immunol 2020; 121:136-143. [PMID: 32200171 DOI: 10.1016/j.molimm.2020.03.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 02/06/2020] [Accepted: 03/09/2020] [Indexed: 01/17/2023]
Abstract
The innate immune system is activated upon virus invasion of a host cell by recognizing viral component, such as dsRNA through specific receptors, resulting in the production of type- I IFNs, which confer an antiviral state within the invaded as well as surrounding cells. In the present study, fibroblast, monocyte and macrophage cells derived from water Buffalo (Bubalus bubalis) were exposed to a synthetic dsRNA analogue, poly I:C to mimic viral invasion in each cell type. Recognition of poly I:C through cytosolic helicase receptors RIG-I and MDA5 molecule lead to the activation of the RLR pathway, subsequently activating the MAVS-IRF3/7 cascade and the production of antiviral effector molecule like IFNβ and ISGs. Within the different cell types, we identified variability in RLR receptor and IFNβ expression after poly I:C administration. Fibroblasts responded quickly and strongly with IFNβ production, followed by macrophages and monocytes. Despite absolute expression variability among different cell types the expression trend of RLRs pathway genes were similar. Length of poly I:C molecule also influence IFNβ expression in response of RLR pathway. Short (LMW) poly I:C induce stronger IFN-β expression in myeloid (macrophage and monocyte) cells. In contrast long (HMW) poly I:C preferably elicit higher IFNβ expression in non-myeloid (fibroblast) cell. Therefore, MDA5 and RIG-1 plays an indispensable role in eliciting antiviral response in non- immune (fibroblast) host cell. Thus, stimulation of RLR pathway with suitable and potentially cell-type specific agonist molecules successfully elicit antiviral state in the host animal, with fibroblasts conferring a stronger antiviral state compared with the monocytes and macrophages.
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Affiliation(s)
- Ashutosh Vats
- Animal Genomics Lab., Animal Biotechnology Centre, ICAR-National Dairy Research Institute, Karnal, Haryana, India
| | - Devika Gautam
- Animal Genomics Lab., Animal Biotechnology Centre, ICAR-National Dairy Research Institute, Karnal, Haryana, India
| | - Jitendra Maharana
- Institute of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan
| | - Jatinder Singh Chera
- Animal Genomics Lab., Animal Biotechnology Centre, ICAR-National Dairy Research Institute, Karnal, Haryana, India
| | - Sushil Kumar
- Animal Genomics Lab., Animal Biotechnology Centre, ICAR-National Dairy Research Institute, Karnal, Haryana, India
| | - Pramod K Rout
- ICAR-Central Institute for Research on Goats, Mathura, Uttar Pradesh, India
| | - Dirk Werling
- The Royal Veterinary College, University of London, Hawkshead Lane, North Mymms, Hatfield, AL9 7TA, UK
| | - Sachinandan De
- Animal Genomics Lab., Animal Biotechnology Centre, ICAR-National Dairy Research Institute, Karnal, Haryana, India.
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12
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Fletcher SJ, Reeves PT, Hoang BT, Mitter N. A Perspective on RNAi-Based Biopesticides. FRONTIERS IN PLANT SCIENCE 2020; 11:51. [PMID: 32117388 PMCID: PMC7028687 DOI: 10.3389/fpls.2020.00051] [Citation(s) in RCA: 84] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 01/15/2020] [Indexed: 05/20/2023]
Abstract
Sustainable agriculture relies on practices and technologies that combine effectiveness with a minimal environmental footprint. RNA interference (RNAi), a eukaryotic process in which transcript expression is reduced in a sequence-specific manner, can be co-opted for the control of plant pests and pathogens in a topical application system. Double-stranded RNA (dsRNA), the key trigger molecule of RNAi, has been shown to provide protection without the need for integration of dsRNA-expressing constructs as transgenes. Consequently, development of RNA-based biopesticides is gaining momentum as a narrow-spectrum alternative to chemical-based control measures, with pests and pathogens targeted with accuracy and specificity. Limitations for a commercially viable product to overcome include stable delivery of the topically applied dsRNA and extension of the duration of protection. In addition to the research focus on delivery of dsRNA, development of regulatory frameworks, risk identification, and establishing avoidance and mitigation strategies is key to widespread deployment of topical RNAi technologies. Once in place, these measures will provide the crop protection industry with the certainty necessary to expend resources on the development of innovative dsRNA-based products. Readily evident risks to human health appear minimal, with multiple barriers to uptake and a long history of consumption of dsRNA from plant material. Unintended impacts to the environment are expected to be most apparent in species closely related to the target. Holistic design practices, which incorporate bioinformatics-based dsRNA selection along with experimental testing, represent important techniques for elimination of adverse impacts.
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Affiliation(s)
- Stephen J. Fletcher
- Centre for Horticultural Science, Queensland Alliance for Agriculture and Food Innovation, University of Queensland, Saint Lucia, QLD, Australia
| | | | - Bao Tram Hoang
- Centre for Horticultural Science, Queensland Alliance for Agriculture and Food Innovation, University of Queensland, Saint Lucia, QLD, Australia
| | - Neena Mitter
- Centre for Horticultural Science, Queensland Alliance for Agriculture and Food Innovation, University of Queensland, Saint Lucia, QLD, Australia
- *Correspondence: Neena Mitter,
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13
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Danilenko ED, Belkina AO, Sysoeva GM. Development of Drugs Based on High-Polymeric Double-Stranded RNA for Antiviral and Antitumor Therapy. BIOCHEMISTRY (MOSCOW) SUPPLEMENT. SERIES B, BIOMEDICAL CHEMISTRY 2019; 13:308-323. [PMID: 32288939 PMCID: PMC7104317 DOI: 10.1134/s1990750819040036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 05/14/2019] [Accepted: 05/16/2019] [Indexed: 12/24/2022]
Abstract
Abstract-The review summarizes literature data on the development of drugs based on natural and synthetic high-polymeric double-stranded RNA (dsRNA), their antiviral, immunoadjuvant, and antitumor properties. Special attention is paid to cell receptors responding to exogenous dsRNA, pathways of dsRNA-dependent antiviral reaction, ability of dsRNA to inhibit growth and induce apoptosis of malignant cells. It has been shown that enhancing the innate immune response with dsRNA can be an effective component in improving methods for treating and preventing infectious and cancer diseases. The further use of dsRNA for the correction of pathological processes of different origin is discussed.
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Affiliation(s)
- E. D. Danilenko
- Institute of Medical Biotechnology, State Research Center of Virology and Biotechnology (SRC VB) “Vector”, Khimzavodskaya ul. 9, 633010 Berdsk, Novosibirsk region Russia
| | - A. O. Belkina
- Institute of Medical Biotechnology, State Research Center of Virology and Biotechnology (SRC VB) “Vector”, Khimzavodskaya ul. 9, 633010 Berdsk, Novosibirsk region Russia
| | - G. M. Sysoeva
- Institute of Medical Biotechnology, State Research Center of Virology and Biotechnology (SRC VB) “Vector”, Khimzavodskaya ul. 9, 633010 Berdsk, Novosibirsk region Russia
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14
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Abram QH, Rodriguez-Ramos T, Bols NC, Katzenback BA, Dixon B. Effect of suboptimal temperature on the regulation of endogenous antigen presentation in a rainbow trout hypodermal fibroblast cell line. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2019; 100:103423. [PMID: 31254564 DOI: 10.1016/j.dci.2019.103423] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 06/08/2019] [Accepted: 06/25/2019] [Indexed: 06/09/2023]
Abstract
Rainbow trout (Oncorhynchus mykiss) face low environmental temperatures over winter months and during extreme low temperature events. Suboptimal temperatures are known to negatively impact the teleost immune system, although there is mixed evidence in rainbow trout as to the effect on the endogenous antigen processing and presentation pathway (EAPP). The EAPP is an important pathway for antiviral defense that involves the presentation of endogenous peptides on the cell surface for recognition by cytotoxic T cells. Using a rainbow trout hypodermal fibroblast (RTHDF) cell line as an in vitro model, we determined that constitutive EAPP transcript levels are not impaired at low temperature, but induction of up-regulation of these transcripts is delayed at the suboptimal temperature following exposure to poly(I:C) or viral haemorrhagic septicaemia virus IVb, which was still able to enter and replicate in the cell line at 4 °C, albeit with reduced efficiency. The delay in the induction of EAPP mRNA level up-regulation following poly(I:C) stimulation coincided with a delay in ifn1 transcript levels and secretion, which is important since interferon-stimulated response elements were identified in the promoter regions of the EAPP-specific members of the pathway, implying that IFN1 is involved in the regulation of these genes. Our results suggest that the ability of rainbow trout to mount an effective immune response to viral pathogens may be lessened at suboptimal temperatures.
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Affiliation(s)
- Quinn H Abram
- Department of Biology, University of Waterloo, Waterloo, Ontario, N2L3G1, Canada.
| | | | - Niels C Bols
- Department of Biology, University of Waterloo, Waterloo, Ontario, N2L3G1, Canada.
| | - Barbara A Katzenback
- Department of Biology, University of Waterloo, Waterloo, Ontario, N2L3G1, Canada.
| | - Brian Dixon
- Department of Biology, University of Waterloo, Waterloo, Ontario, N2L3G1, Canada.
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15
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Danilenko ED, Belkina AO, Sysoeva GM. [Development of drugs on the basis of high-polymeric double-stranded RNA for antiviral and antitumor therapy]. BIOMEDIT︠S︡INSKAI︠A︡ KHIMII︠A︡ 2019; 65:277-293. [PMID: 31436169 DOI: 10.18097/pbmc20196504277] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The review summarizes literature data on the development of drugs based on natural and synthetic high-polymeric double-stranded RNA, and their antiviral, immunoadjuvant and antitumor properties. Special attention is paid to cell receptors responding to exogenous dsRNA, the paths of dsRNA-dependent antiviral reaction, ability of dsRNA to inhibit growth and induce apoptosis ofmalignant cells. It has been shown that enhancing the innate immune response with dsRNA can be an effective component in improving methods for treating and preventing infectious and cancer diseases. The further use of dsRNA for the correction of pathological processes of different origin is discussed.
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Affiliation(s)
- E D Danilenko
- Institute of Medical Biotechnology, State Research Center of Virology and Biotechnology "Vector", Berdsk, Russia
| | - A O Belkina
- Institute of Medical Biotechnology, State Research Center of Virology and Biotechnology "Vector", Berdsk, Russia
| | - G M Sysoeva
- Institute of Medical Biotechnology, State Research Center of Virology and Biotechnology "Vector", Berdsk, Russia
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16
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Panda D, Gjinaj E, Bachu M, Squire E, Novatt H, Ozato K, Rabin RL. IRF1 Maintains Optimal Constitutive Expression of Antiviral Genes and Regulates the Early Antiviral Response. Front Immunol 2019; 10:1019. [PMID: 31156620 PMCID: PMC6529937 DOI: 10.3389/fimmu.2019.01019] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 04/23/2019] [Indexed: 12/13/2022] Open
Abstract
Viral defense at mucosal sites depends on interferons (IFN) and IFN stimulated genes (ISGs), either of which may be constitutively expressed to maintain an “antiviral state” (AVS). However, the mechanisms that govern the AVS are poorly defined. Using a BEAS-2B respiratory epithelial cell line deficient in IRF1, we demonstrate higher susceptibility to infection with vesicular stomatitis virus (VSV) and influenza virus. IRF1-mediated restriction of VSV is IFN-independent, as blockade of types I and III IFNs and JAK-STAT signaling before infection did not affect VSV infection of either parent or IRF1 KO cells. Transcriptome analysis revealed that IRF1 regulates constitutive expression of ~300 genes, including antiviral ISGs: OAS2, BST2, and RNASEL and knockdown of any of these IRF1-dependent genes increased VSV infection. Additionally, IRF1 enhances rapid expression of IFNβ and IFNλ after stimulation with poly I:C and also regulates ISG expression. Mechanistically, IRF1 enhances recruitment of BRD4 to promotor-enhancer regions of ISGs for rapid expression and maintains levels of histone H3K4me1 for optimal constitutive expression. Finally, IRF1 also regulates constitutive expression of TLR2 and TLR3 and promotes signaling through these pattern recognition receptors (PRR). These data reveal multiple roles for IRF1 toward effective anti-viral responses by maintaining IFN-independent constitutive expression of anti-viral ISGs and supporting early IFN-dependent responses to PRR stimulation.
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Affiliation(s)
- Debasis Panda
- Center for Biologics Evaluation and Research, US Food and Drug Administration, Silver Spring, MD, United States
| | - Erisa Gjinaj
- Center for Biologics Evaluation and Research, US Food and Drug Administration, Silver Spring, MD, United States
| | - Mahesh Bachu
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, United States
| | - Erica Squire
- Center for Biologics Evaluation and Research, US Food and Drug Administration, Silver Spring, MD, United States
| | - Hilary Novatt
- Center for Biologics Evaluation and Research, US Food and Drug Administration, Silver Spring, MD, United States
| | - Keiko Ozato
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD, United States
| | - Ronald L Rabin
- Center for Biologics Evaluation and Research, US Food and Drug Administration, Silver Spring, MD, United States
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17
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Visconti V, Eychenne M, Darboux I. Modulation of antiviral immunity by the ichnovirus HdIV in Spodoptera frugiperda. Mol Immunol 2019; 108:89-101. [PMID: 30784767 DOI: 10.1016/j.molimm.2019.02.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2019] [Revised: 02/13/2019] [Accepted: 02/13/2019] [Indexed: 12/12/2022]
Abstract
Polydnaviruses (PDVs) are obligatory symbionts found in thousands of endoparasitoid species and essential for successful parasitism. The two genera of PDVs, ichnovirus (IV) and bracovirus (BV), use different sets of virulence factors to ensure successful parasitization of the host. Previous studies have shown that PDVs target apoptosis, one of the innate antiviral responses in many host organisms. However, IV and BV have been shown to have opposite effects on this process. BV induces apoptosis in host cells, whereas some IV proteins have been shown to have anti-apoptotic activity. The different biological contexts in which the assays were performed may account for this difference. In this study, we evaluated the interplay between apoptosis and the ichnovirus HdIV from the parasitoid Hyposoter didymator, in the HdIV-infected hemocytes and fat bodies of S. frugiperda larvae, and in the Sf9 insect cell line challenged with HdIV. We found that HdIV induced cell death in hemocytes and fat bodies, whereas anti-apoptotic activity was observed in HdIV-infected Sf9 cells, with and without stimulation with viral PAMPs or chemical inducers. We also used an RT-qPCR approach to determine the expression profiles of a set of genes known to encode key components of the other main antiviral immune pathways described in insects. The analysis of immune gene transcription highlighted differences in antiviral responses to HdIV as a function of host cell type. However, all these antiviral pathways appeared to be neutralized by low levels of expression for the genes encoding the key components of these pathways, in all biological contexts. Finally, we investigated the effect of HdIV on the general antiviral defenses of the lepidopteran larvae in more detail, by studying the survival of S. frugiperda co-infected with HdIV and the entomopathogenic densovirus JcDV. Coinfected S. frugiperda larvae have increased resistance to JcDV at an early phase of infection, whereas HdIV effects enhance the virulence of the virus at later stages of infection. Overall, these results reveal complex interactions between HdIV and its cellular environment.
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Affiliation(s)
- Vincent Visconti
- UMR 1333 INRA - Université de Montpellier Diversité, Génomes & Interactions Microorganismes-Insectes (DGIMI), 34095 Montpellier, France.
| | - Magali Eychenne
- UMR 1333 INRA - Université de Montpellier Diversité, Génomes & Interactions Microorganismes-Insectes (DGIMI), 34095 Montpellier, France
| | - Isabelle Darboux
- UMR 1333 INRA - Université de Montpellier Diversité, Génomes & Interactions Microorganismes-Insectes (DGIMI), 34095 Montpellier, France.
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18
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Interferon Regulatory Factor 3-Mediated Signaling Limits Middle-East Respiratory Syndrome (MERS) Coronavirus Propagation in Cells from an Insectivorous Bat. Viruses 2019; 11:v11020152. [PMID: 30781790 PMCID: PMC6410008 DOI: 10.3390/v11020152] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 02/08/2019] [Accepted: 02/11/2019] [Indexed: 12/14/2022] Open
Abstract
Insectivorous bats are speculated to be ancestral hosts of Middle-East respiratory syndrome (MERS) coronavirus (CoV). MERS-CoV causes disease in humans with thirty-five percent fatality, and has evolved proteins that counteract human antiviral responses. Since bats experimentally infected with MERS-CoV do not develop signs of disease, we tested the hypothesis that MERS-CoV would replicate less efficiently in bat cells than in human cells because of its inability to subvert antiviral responses in bat cells. We infected human and bat (Eptesicus fuscus) cells with MERS-CoV and observed that the virus grew to higher titers in human cells. MERS-CoV also effectively suppressed the antiviral interferon beta (IFNβ) response in human cells, unlike in bat cells. To determine if IRF3, a critical mediator of the interferon response, also regulated the response in bats, we examined the response of IRF3 to poly(I:C), a synthetic analogue of viral double-stranded RNA. We observed that bat IRF3 responded to poly(I:C) by nuclear translocation and post-translational modifications, hallmarks of IRF3 activation. Suppression of IRF3 by small-interfering RNA (siRNA) demonstrated that IRF3 was critical for poly(I:C) and MERS-CoV induced induction of IFNβ in bat cells. Our study demonstrates that innate antiviral signaling in E. fuscus bat cells is resistant to MERS-CoV-mediated subversion.
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19
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Tachypleus tridentatus Lectin Enhances Oncolytic Vaccinia Virus Replication to Suppress In Vivo Hepatocellular Carcinoma Growth. Mar Drugs 2018; 16:md16060200. [PMID: 29880736 PMCID: PMC6025575 DOI: 10.3390/md16060200] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Revised: 06/01/2018] [Accepted: 06/05/2018] [Indexed: 02/06/2023] Open
Abstract
Lectins play diverse roles in physiological processes as biological recognition molecules. In this report, a gene encoding Tachypleus tridentatus Lectin (TTL) was inserted into an oncolytic vaccinia virus (oncoVV) vector to form oncoVV-TTL, which showed significant antitumor activity in a hepatocellular carcinoma mouse model. Furthermore, TTL enhanced oncoVV replication through suppressing antiviral factors expression such as interferon-inducible protein 16 (IFI16), mitochondrial antiviral signaling protein (MAVS) and interferon-beta (IFN-β). Further investigations revealed that oncoVV-TTL replication was highly dependent on ERK activity. This study might provide insights into a novel way of the utilization of TTL in oncolytic viral therapies.
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20
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Poynter SJ, Monjo AL, DeWitte-Orr SJ. Identification of three class A scavenger receptors from rainbow trout (Oncorhynchus mykiss): SCARA3, SCARA4, and SCARA5. FISH & SHELLFISH IMMUNOLOGY 2018; 76:121-125. [PMID: 29471060 DOI: 10.1016/j.fsi.2018.02.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 02/06/2018] [Accepted: 02/14/2018] [Indexed: 06/08/2023]
Abstract
Class A scavenger receptors (SR-As) are a family of five surface receptors whose functions in mammals are associated with innate immunity; however, their role in fish immunity requires further elucidation. The present study identifies, performs sequence analysis, and constitutive transcript expression analysis for three SR-A family members, SCARA3, SCARA4 and SCARA5, from rainbow trout. This work will provide a basis for future studies on SR-A function and their role in innate immunity in this economically important fish.
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Affiliation(s)
- S J Poynter
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
| | - A L Monjo
- Department of Biology, Wilfrid Laurier University, Waterloo, Ontario, Canada
| | - S J DeWitte-Orr
- Department of Biology, Wilfrid Laurier University, Waterloo, Ontario, Canada; Department of Health Sciences, Wilfrid Laurier University, Waterloo, Ontario, Canada.
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21
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Baid K, Nellimarla S, Huynh A, Boulton S, Guarné A, Melacini G, Collins SE, Mossman KL. Direct binding and internalization of diverse extracellular nucleic acid species through the collagenous domain of class A scavenger receptors. Immunol Cell Biol 2018; 96:922-934. [DOI: 10.1111/imcb.12052] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 03/24/2018] [Accepted: 03/29/2018] [Indexed: 01/12/2023]
Affiliation(s)
- Kaushal Baid
- Biochemistry and Biomedical Sciences; McMaster Immunology Research Centre; Michael DeGroote Institute for Infectious Disease Research; McMaster University; Hamilton ON Canada
| | - Srinivas Nellimarla
- Department of Pathology and Molecular Medicine; McMaster Immunology Research Centre; Michael DeGroote Institute for Infectious Disease Research; McMaster University; Hamilton ON Canada
| | - Angela Huynh
- Biochemistry and Biomedical Sciences; McMaster Immunology Research Centre; Michael DeGroote Institute for Infectious Disease Research; McMaster University; Hamilton ON Canada
| | - Stephen Boulton
- Biochemistry and Biomedical Sciences; McMaster Immunology Research Centre; Michael DeGroote Institute for Infectious Disease Research; McMaster University; Hamilton ON Canada
| | - Alba Guarné
- Biochemistry and Biomedical Sciences; McMaster Immunology Research Centre; Michael DeGroote Institute for Infectious Disease Research; McMaster University; Hamilton ON Canada
| | - Giuseppe Melacini
- Biochemistry and Biomedical Sciences; McMaster Immunology Research Centre; Michael DeGroote Institute for Infectious Disease Research; McMaster University; Hamilton ON Canada
- Department of Chemistry and Chemical Biology; McMaster University; Hamilton ON Canada
| | - Susan E Collins
- Department of Pathology and Molecular Medicine; McMaster Immunology Research Centre; Michael DeGroote Institute for Infectious Disease Research; McMaster University; Hamilton ON Canada
| | - Karen L Mossman
- Biochemistry and Biomedical Sciences; McMaster Immunology Research Centre; Michael DeGroote Institute for Infectious Disease Research; McMaster University; Hamilton ON Canada
- Department of Pathology and Molecular Medicine; McMaster Immunology Research Centre; Michael DeGroote Institute for Infectious Disease Research; McMaster University; Hamilton ON Canada
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22
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Poynter SJ, DeWitte-Orr SJ. Understanding Viral dsRNA-Mediated Innate Immune Responses at the Cellular Level Using a Rainbow Trout Model. Front Immunol 2018; 9:829. [PMID: 29740439 PMCID: PMC5924774 DOI: 10.3389/fimmu.2018.00829] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 04/05/2018] [Indexed: 12/20/2022] Open
Abstract
Viruses across genome types produce long dsRNA molecules during replication [viral (v-) dsRNA]. dsRNA is a potent signaling molecule and inducer of type I interferon (IFN), leading to the production of interferon-stimulated genes (ISGs), and a protective antiviral state within the cell. Research on dsRNA-induced immune responses has relied heavily on a commercially available, and biologically irrelevant dsRNA, polyinosinic:polycytidylic acid (poly I:C). Alternatively, dsRNA can be produced by in vitro transcription (ivt-) dsRNA, with a defined sequence and length. We hypothesized that ivt-dsRNA, containing legitimate viral sequence and length, would be a more appropriate proxy for v-dsRNA, compared with poly I:C. This is the first study to investigate the effects of v-dsRNA on the innate antiviral response and to compare v-dsRNA to ivt-dsRNA-induced responses in fish cells, specifically rainbow trout. Previously, class A scavenger receptors (SR-As) were found to be surface receptors for poly I:C in rainbow trout cells. In this study, ivt-dsRNA binding was blocked by poly I:C and v-dsRNA, as well as SR-A competitive ligands, suggesting all three dsRNA molecules are recognized by SR-As. Downstream innate antiviral effects were determined by measuring IFN and ISG transcript levels using qRT-PCR and antiviral assays. Similar to what has been shown previously with ivt-dsRNA, v-dsRNA was able to induce IFN and ISG transcript production between 3 and 24 h, and its effects were length dependent (i.e., longer v-dsRNA produced a stronger response). Interestingly, when v-dsRNA and ivt-dsRNA were length and sequence matched both molecules induced statistically similar IFN and ISG transcript levels, which resulted in similar antiviral states against two aquatic viruses. To pursue sequence effects further, three ivt-dsRNA molecules of the same length but different sequences (including host and viral sequences) were tested for their ability to induce IFN/ISG transcripts and an antiviral state. All three induced responses similarly. This study is the first of its kind to look at the effects v-dsRNA in fish cells as well as to compare ivt-dsRNA to v-dsRNA, and suggests that ivt-dsRNA may be a good surrogate for v-dsRNA in the study of dsRNA-induced responses and potential future antiviral therapies.
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Affiliation(s)
- Sarah J. Poynter
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
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23
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Collet B, Collins C, Lester K. Engineered cell lines for fish health research. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2018; 80:34-40. [PMID: 28108246 DOI: 10.1016/j.dci.2017.01.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 01/13/2017] [Accepted: 01/16/2017] [Indexed: 06/06/2023]
Abstract
As fish farming continues to increase worldwide, the related research areas of fish disease and immunology are also expanding, aided by the revolution in access to genomic information and molecular technology. The genomes of most fish species of economic importance are now available and annotation based on sequence homology with characterised genomes is underway. However, while useful, functional homology is more difficult to determine, there being a lack of widely distributed and well characterised reagents such as monoclonal antibodies, traditionally used in mammalian studies, to help with confirming functions and cellular interactions of fish molecules. In this context, fish cell lines and the possibility of their genetic engineering offer good prospects for studying functional genomics with respect to fish diseases. In this review, we will give an overview of available permanently genetically engineered fish cell lines, as cell-based reporter systems or platforms for expression of endogenous immune or pathogen genes, to investigate interactions and function. The advantages of such systems and the technical challenge for their development will be discussed.
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24
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Eichwald C, De Lorenzo G, Schraner EM, Papa G, Bollati M, Swuec P, de Rosa M, Milani M, Mastrangelo E, Ackermann M, Burrone OR, Arnoldi F. Identification of a Small Molecule That Compromises the Structural Integrity of Viroplasms and Rotavirus Double-Layered Particles. J Virol 2018; 92:e01943-17. [PMID: 29142132 PMCID: PMC5774888 DOI: 10.1128/jvi.01943-17] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 11/08/2017] [Indexed: 01/12/2023] Open
Abstract
Despite the availability of two attenuated vaccines, rotavirus (RV) gastroenteritis remains an important cause of mortality among children in developing countries, causing about 215,000 infant deaths annually. Currently, there are no specific antiviral therapies available. RV is a nonenveloped virus with a segmented double-stranded RNA genome. Viral genome replication and assembly of transcriptionally active double-layered particles (DLPs) take place in cytoplasmic viral structures called viroplasms. In this study, we describe strong impairment of the early stages of RV replication induced by a small molecule known as an RNA polymerase III inhibitor, ML-60218 (ML). This compound was found to disrupt already assembled viroplasms and to hamper the formation of new ones without the need for de novo transcription of cellular RNAs. This phenotype was correlated with a reduction in accumulated viral proteins and newly made viral genome segments, disappearance of the hyperphosphorylated isoforms of the viroplasm-resident protein NSP5, and inhibition of infectious progeny virus production. In in vitro transcription assays with purified DLPs, ML showed dose-dependent inhibitory activity, indicating the viral nature of its target. ML was found to interfere with the formation of higher-order structures of VP6, the protein forming the DLP outer layer, without compromising its ability to trimerize. Electron microscopy of ML-treated DLPs showed dose-dependent structural damage. Our data suggest that interactions between VP6 trimers are essential, not only for DLP stability, but also for the structural integrity of viroplasms in infected cells.IMPORTANCE Rotavirus gastroenteritis is responsible for a large number of infant deaths in developing countries. Unfortunately, in the countries where effective vaccines are urgently needed, the efficacy of the available vaccines is particularly low. Therefore, the development of antivirals is an important goal, as they might complement the available vaccines or represent an alternative option. Moreover, they may be decisive in fighting the acute phase of infection. This work describes the inhibitory effect on rotavirus replication of a small molecule initially reported as an RNA polymerase III inhibitor. The molecule is the first chemical compound identified that is able to disrupt viroplasms, the viral replication machinery, and to compromise the stability of DLPs by targeting the viral protein VP6. This molecule thus represents a starting point in the development of more potent and less cytotoxic compounds against rotavirus infection.
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Affiliation(s)
| | - Giuditta De Lorenzo
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
| | | | - Guido Papa
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
| | - Michela Bollati
- Biophysics Institute of the National Research Council (CNR-IBF), Department of Biosciences, University of Milan, Milan, Italy
| | - Paolo Swuec
- Pediatric Clinical Research Center Fondazione Romeo ed Enrica Invernizzi, Department of Biosciences, University of Milan, Milan, Italy
| | - Matteo de Rosa
- Biophysics Institute of the National Research Council (CNR-IBF), Department of Biosciences, University of Milan, Milan, Italy
| | - Mario Milani
- Biophysics Institute of the National Research Council (CNR-IBF), Department of Biosciences, University of Milan, Milan, Italy
| | - Eloise Mastrangelo
- Biophysics Institute of the National Research Council (CNR-IBF), Department of Biosciences, University of Milan, Milan, Italy
| | | | - Oscar R Burrone
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
| | - Francesca Arnoldi
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
- Department of Medicine, Surgery and Health Sciences, University of Trieste, Trieste, Italy
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Poynter SJ, Monjo AL, Micheli G, DeWitte-Orr SJ. Scavengers for bacteria: Rainbow trout have two functional variants of MARCO that bind to gram-negative and -positive bacteria. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2017; 77:95-105. [PMID: 28743433 DOI: 10.1016/j.dci.2017.07.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 07/21/2017] [Accepted: 07/21/2017] [Indexed: 06/07/2023]
Abstract
Class A scavenger receptors (SR-As) are a family of surface-expressed receptors who bind a wide range of polyanionic ligands including bacterial components and nucleic acids and play a role in innate immunity. Macrophage receptor with collagenous structure (MARCO) is a SR-A family member that has been studied in mammals largely for its role in binding bacteria. To date there is little information about SR-As in general and MARCO specifically in fish, particularly what ligands individual SR-A family members bind remains largely unknown. In the present study two novel rainbow trout MARCO transcript variants have been identified and their sequence and putative protein domains have been analyzed. When overexpressed in CHSE-214, a cell line that appears to lack functional scavenger receptors, GFP-tagged rtMARCO-1 and rtMARCO-2 were able to bind gram-positive, and gram-negative bacteria of both mammalian and aquatic sources. rtMARCO appears to bind bacteria via its scavenger receptor cysteine-rich (SRCR) domain, because SRCR deleted rtMARCO-1 and -2 were unable to bind bacteria. rtMARCO did not show any binding to the yeast cell wall component zymosan or to double-stranded (ds)RNA. This is the first time rainbow trout MARCO sequences have been identified and the first in-depth study exploring their ligand binding profile. This study provides novel insight into the role of rainbow trout MARCO in bacterial innate immunity.
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Affiliation(s)
- Sarah J Poynter
- Department of Biology, University of Waterloo, 200 University Ave W, Waterloo, ON N2L 3G1, Canada
| | - Andrea L Monjo
- Department of Biology, Wilfrid Laurier University, 75 University Ave W, Waterloo, ON N2L 3C5, Canada
| | - Gabriella Micheli
- Department of Health Sciences, Wilfrid Laurier University, 75 University Ave W, Waterloo, ON N2L 3C5, Canada
| | - Stephanie J DeWitte-Orr
- Department of Biology, Wilfrid Laurier University, 75 University Ave W, Waterloo, ON N2L 3C5, Canada; Department of Health Sciences, Wilfrid Laurier University, 75 University Ave W, Waterloo, ON N2L 3C5, Canada.
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26
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Tree MO, McKellar DR, Kieft KJ, Watson AM, Ryman KD, Conway MJ. Insect-specific flavivirus infection is restricted by innate immunity in the vertebrate host. Virology 2016; 497:81-91. [DOI: 10.1016/j.virol.2016.07.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 06/18/2016] [Accepted: 07/05/2016] [Indexed: 11/15/2022]
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27
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Doherty L, Poynter SJ, Aloufi A, DeWitte-Orr SJ. Fish viruses make dsRNA in fish cells: characterization of dsRNA production in rainbow trout (Oncorhynchus mykiss) cells infected with viral haemorrhagic septicaemia virus, chum salmon reovirus and frog virus 3. JOURNAL OF FISH DISEASES 2016; 39:1133-1137. [PMID: 26775727 DOI: 10.1111/jfd.12443] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 10/30/2015] [Accepted: 10/30/2015] [Indexed: 06/05/2023]
Affiliation(s)
- L Doherty
- Department of Health Sciences, Wilfrid Laurier University, Waterloo, ON, Canada
| | - S J Poynter
- Department of Health Sciences, Wilfrid Laurier University, Waterloo, ON, Canada
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
| | - A Aloufi
- Department of Health Sciences, Wilfrid Laurier University, Waterloo, ON, Canada
| | - S J DeWitte-Orr
- Department of Health Sciences, Wilfrid Laurier University, Waterloo, ON, Canada
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Membrane Perturbation-Associated Ca2+ Signaling and Incoming Genome Sensing Are Required for the Host Response to Low-Level Enveloped Virus Particle Entry. J Virol 2015; 90:3018-27. [PMID: 26719279 DOI: 10.1128/jvi.02642-15] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 12/23/2015] [Indexed: 12/25/2022] Open
Abstract
UNLABELLED The type I interferon (IFN) response is an important aspect of innate antiviral defense, and the transcription factor IRF3 plays an important role in its induction. Membrane perturbation during fusion, a necessary step for enveloped virus particle entry, appears sufficient to induce transcription of a subset of IFN-stimulated genes (ISGs) in an IRF3-dependent, IFN-independent fashion. IRF3 is emerging as a central node in host cell stress responses, although it remains unclear how different forms of stress activate IRF3. Here, we investigated the minimum number of Sendai virus (SeV) and human cytomegalovirus (HCMV) particles required to activate IRF3 and trigger an antiviral response. We found that Ca(2+) signaling associated with membrane perturbation and recognition of incoming viral genomes by cytosolic nucleic acid receptors are required to activate IRF3 in response to fewer than 13 particles of SeV and 84 particles of HCMV per cell. Moreover, it appears that Ca(2+) signaling is important for activation of STING and IRF3 following HCMV particle entry, suggesting that Ca(2+) signaling sensitizes cells to recognize genomes within incoming virus particles. To our knowledge, this is the first evidence that cytosolic nucleic acid sensors recognize genomes within incoming virus particles prior to virus replication. These studies highlight the exquisite sensitivity of the cellular response to low-level stimuli and suggest that virus particle entry is sensed as a stress signal. IMPORTANCE The mechanism by which replicating viruses trigger IRF3 activation and type I IFN induction through the generation and accumulation of viral pathogen-associated molecular patterns has been well characterized. However, the mechanism by which enveloped virus particle entry mediates a stress response, leading to IRF3 activation and the IFN-independent response, remained elusive. Here, we find that Ca(2+) signaling associated with membrane perturbation appears to sensitize cells to recognize genomes within incoming virus particles. To our knowledge, this is the first study to show that cytosolic receptors recognize genomes within incoming virus particles prior to virus replication. These findings not only highlight the sensitivity of cellular responses to low-level virus particle stimulation, but provide important insights into how nonreplicating virus vectors or synthetic lipid-based carriers used as clinical delivery vehicles activate innate immune responses.
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Jin HY, Gonzalez-Martin A, Miletic AV, Lai M, Knight S, Sabouri-Ghomi M, Head SR, Macauley MS, Rickert RC, Xiao C. Transfection of microRNA Mimics Should Be Used with Caution. Front Genet 2015; 6:340. [PMID: 26697058 PMCID: PMC4667072 DOI: 10.3389/fgene.2015.00340] [Citation(s) in RCA: 124] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 11/12/2015] [Indexed: 12/19/2022] Open
Abstract
Transient transfection of chemically synthesized microRNA (miRNA) mimics is being used extensively to study the functions and mechanisms of endogenous miRNAs. However, it remains unclear whether transfected miRNAs behave similarly to endogenous miRNAs. Here we show that transient transfection of miRNA mimics into HeLa cells by a commonly used method led to the accumulation of high molecular weight RNA species and a few hundred fold increase in mature miRNA levels. In contrast, expression of the same miRNAs through lentiviral infection or plasmid transfection of HeLa cells, transgenic expression in primary lymphocytes, and endogenous overexpression in lymphoma and leukemia cell lines did not lead to the appearance of high molecular weight RNA species. The increase of mature miRNA levels in these cells was below 10-fold, which was sufficient to suppress target gene expression and to drive lymphoma development in mice. Moreover, transient transfection of miRNA mimics at high concentrations caused non-specific alterations in gene expression, while at low concentrations achieved expression levels comparable to other methods but failed to efficiently suppress target gene expression. Small RNA deep sequencing analysis revealed that the guide strands of miRNA mimics were frequently mutated, while unnatural passenger strands of some miRNA mimics accumulated to high levels. The high molecular weight RNA species were a heterogeneous mixture of several classes of RNA species generated by concatemerization, 5'- and 3'-end tailing of miRNA mimics. We speculate that the supraphysiological levels of mature miRNAs and these artifactual RNA species led to non-specific changes in gene expression. Our results have important implications for the design and interpretation of experiments primarily employing transient transfection of miRNA mimics.
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Affiliation(s)
- Hyun Yong Jin
- Department of Immunology and Microbial Science, The Scripps Research Institute La Jolla, CA, USA ; Kellogg School of Science and Technology, The Scripps Research Institute La Jolla, CA, USA
| | - Alicia Gonzalez-Martin
- Department of Immunology and Microbial Science, The Scripps Research Institute La Jolla, CA, USA
| | - Ana V Miletic
- Program on Immunity and Pathogenesis, Sanford-Burnham Medical Research Institute La Jolla, CA, USA
| | - Maoyi Lai
- Department of Immunology and Microbial Science, The Scripps Research Institute La Jolla, CA, USA
| | - Sarah Knight
- Department of Immunology and Microbial Science, The Scripps Research Institute La Jolla, CA, USA ; Department of Cell and Molecular Biology, The Scripps Research Institute La Jolla, CA, USA ; Department of Chemical Physiology, The Scripps Research Institute La Jolla, CA, USA
| | - Mohsen Sabouri-Ghomi
- Department of Immunology and Microbial Science, The Scripps Research Institute La Jolla, CA, USA
| | - Steven R Head
- Next Generation Sequencing Core, The Scripps Research Institute La Jolla, CA, USA
| | - Matthew S Macauley
- Department of Immunology and Microbial Science, The Scripps Research Institute La Jolla, CA, USA ; Department of Cell and Molecular Biology, The Scripps Research Institute La Jolla, CA, USA ; Department of Chemical Physiology, The Scripps Research Institute La Jolla, CA, USA
| | - Robert C Rickert
- Program on Immunity and Pathogenesis, Sanford-Burnham Medical Research Institute La Jolla, CA, USA
| | - Changchun Xiao
- Department of Immunology and Microbial Science, The Scripps Research Institute La Jolla, CA, USA
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Lee CC, Wu CC, Lin TL. Role of chicken melanoma differentiation-associated gene 5 in induction and activation of innate and adaptive immune responses to infectious bursal disease virus in cultured macrophages. Arch Virol 2015; 160:3021-35. [PMID: 26392283 DOI: 10.1007/s00705-015-2612-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 09/13/2015] [Indexed: 01/12/2023]
Abstract
The objective of the present study was to determine if chicken melanoma-differentiation-associated gene 5 (MDA5) senses infectious bursal disease virus infection to induce innate immunity that bridges to adaptive immunity. During IBDV infection in HD11 cells, IBDV titers and RNA loads increased up to 3.4 × 10(7) plaque-forming units (PFU)/mL and 1114 ng/µL, respectively, at 24 hours postinfection (hpi). IBDV infection in HD11 cells induced significantly upregulated (p < 0.05) expression levels of chicken MDA5 (59-fold), interferon-β (IFN-β) (693-fold), dsRNA-dependent protein kinase (PKR) (4-fold), 2', 5'-oligoadenylate synthetase (OAS) (286-fold), myxovirus resistance gene (Mx) (22-fold), interleukin-1β (IL-1β) (5-fold), IL-6 (146-fold), IL-8 (4-fold), IL-10 (4-fold), inducible nitric oxide synthase (iNOS) (15-fold), and major histocompatibility complex class I (MHC class I) (4-fold). Nitric oxide production in the culture supernatants increased significantly (p < 0.05) up to 6.5 μM at 24 hpi. The expressed chMDA5 and IBDV-derived dsRNA were localized in the cytoplasm of HD11 cells during IBDV infection. ChMDA5-knockdown HD11 cells had significantly higher (p < 0.05) IBDV RNA loads at 24 hpi and significantly lower (p < 0.05) nitric oxide production and expression levels of chicken MDA5, IFN-β, PKR, OAS, Mx, IL-1β, IL-6, IL-8, IL-12(p40), IL-18, IL-10, iNOS, MHC class I and CD86 at 24 hpi. In addition, chMDA5 overexpression in HD11 cells resulted in significantly reduced (p < 0.05) IBDV titers and RNA loads and significantly increased (p < 0.05) nitric oxide production at 16 and 24 hpi. It also resulted in significantly higher (p < 0.05) expression levels of chicken MDA5, IFN-β, PKR, OAS, Mx, IL-1β, IL-6, IL-8, IL-12(p40), IL-10 and iNOS at 2 hpi. In conclusion, the results indicate that chMDA5 senses IBDV infection in chicken macrophages, and this is associated with IBDV-induced expression of IFN-β and initiation of an innate immune response that in turn activates the adaptive immune response and limits IBDV replication.
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Affiliation(s)
- Chih-Chun Lee
- Department of Comparative Pathobiology, Purdue University, 406, S. University St, West Lafayette, IN, 47907, USA
| | - Ching Ching Wu
- Department of Comparative Pathobiology, Purdue University, 406, S. University St, West Lafayette, IN, 47907, USA
| | - Tsang Long Lin
- Department of Comparative Pathobiology, Purdue University, 406, S. University St, West Lafayette, IN, 47907, USA.
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Nellimarla S, Baid K, Loo YM, Gale M, Bowdish DME, Mossman KL. Class A Scavenger Receptor-Mediated Double-Stranded RNA Internalization Is Independent of Innate Antiviral Signaling and Does Not Require Phosphatidylinositol 3-Kinase Activity. THE JOURNAL OF IMMUNOLOGY 2015; 195:3858-65. [PMID: 26363049 DOI: 10.4049/jimmunol.1501028] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 08/17/2015] [Indexed: 11/19/2022]
Abstract
dsRNA is a potent trigger of innate immune signaling, eliciting effects within virally infected cells and after release from dying cells. Given its inherent stability, extracellular dsRNA induces both local and systemic effects. Although the class A scavenger receptors (SR-As) mediate dsRNA entry, it is unknown whether they contribute to signaling beyond ligand internalization. In this study, we investigated whether SR-As contribute to innate immune signaling independent of the classic TLR and retinoic acid-inducible gene-I-like receptor (RLR) pathways. We generated a stable A549 human epithelial cell line with inducible expression of the hepatitis C virus protease NS3/4A, which efficiently cleaves TRIF and IFN-β promoter stimulator 1, adaptors for TLR3 and the RLRs, respectively. Cells expressing NS3/4A and TLR3/MyD88/IFN-β promoter stimulator 1(-/-) mouse embryonic fibroblasts completely lacked antiviral activity to extracellular dsRNA relative to control cells, suggesting that SR-As do not possess signaling capacity independent of TLR3 or the RLRs. Previous studies implicated PI3K signaling in SR-A-mediated activities and in downstream production of type I IFN. We found that SR-A-mediated dsRNA internalization occurs independent of PI3K activation, whereas downstream signaling leading to IFN production was partially dependent on PI3K activity. Overall, these findings suggest that SR-A-mediated dsRNA internalization is independent of innate antiviral signaling.
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Affiliation(s)
- Srinivas Nellimarla
- Department of Pathology and Molecular Medicine, McMaster Immunology Research Center, Michael DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada L8S 4K1
| | - Kaushal Baid
- Department of Pathology and Molecular Medicine, McMaster Immunology Research Center, Michael DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada L8S 4K1
| | - Yueh-Ming Loo
- Department of Immunology, Center for Innate Immunity and Immune Disease, School of Medicine, University of Washington, Seattle, WA 98109; and
| | - Michael Gale
- Department of Immunology, Center for Innate Immunity and Immune Disease, School of Medicine, University of Washington, Seattle, WA 98109; and
| | - Dawn M E Bowdish
- Department of Pathology and Molecular Medicine, McMaster Immunology Research Center, Michael DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada L8S 4K1
| | - Karen L Mossman
- Department of Pathology and Molecular Medicine, McMaster Immunology Research Center, Michael DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada L8S 4K1; Department of Biochemistry and Biomedical Sciences, McMaster Immunology Research Center, Michael DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada L8S 4K1
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32
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Double-Stranded RNA Is Detected by Immunofluorescence Analysis in RNA and DNA Virus Infections, Including Those by Negative-Stranded RNA Viruses. J Virol 2015; 89:9383-92. [PMID: 26136565 DOI: 10.1128/jvi.01299-15] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 06/23/2015] [Indexed: 12/14/2022] Open
Abstract
UNLABELLED Early biochemical studies of viral replication suggested that most viruses produce double-stranded RNA (dsRNA), which is essential for the induction of the host immune response. However, it was reported in 2006 that dsRNA could be detected by immunofluorescence antibody staining in double-stranded DNA and positive-strand RNA virus infections but not in negative-strand RNA virus infections. Other reports in the literature seemed to support these observations. This suggested that negative-strand RNA viruses produce little, if any, dsRNA or that more efficient viral countermeasures to mask dsRNA are mounted. Because of our interest in the use of dsRNA antibodies for virus discovery, particularly in pathological specimens, we wanted to determine how universal immunostaining for dsRNA might be in animal virus infections. We have detected the in situ formation of dsRNA in cells infected with vesicular stomatitis virus, measles virus, influenza A virus, and Nyamanini virus, which represent viruses from different negative-strand RNA virus families. dsRNA was also detected in cells infected with lymphocytic choriomeningitis virus, an ambisense RNA virus, and minute virus of mice (MVM), a single-stranded DNA (ssDNA) parvovirus, but not hepatitis B virus. Although dsRNA staining was primarily observed in the cytoplasm, it was also seen in the nucleus of cells infected with influenza A virus, Nyamanini virus, and MVM. Thus, it is likely that most animal virus infections produce dsRNA species that can be detected by immunofluorescence staining. The apoptosis induced in several uninfected cell lines failed to upregulate dsRNA formation. IMPORTANCE An effective antiviral host immune response depends on recognition of viral invasion and an intact innate immune system as a first line of defense. Double-stranded RNA (dsRNA) is a viral product essential for the induction of innate immunity, leading to the production of type I interferons (IFNs) and the activation of hundreds of IFN-stimulated genes. The present study demonstrates that infections, including those by ssDNA viruses and positive- and negative-strand RNA viruses, produce dsRNAs detectable by standard immunofluorescence staining. While dsRNA staining was primarily observed in the cytoplasm, nuclear staining was also present in some RNA and DNA virus infections. The nucleus is unlikely to have pathogen-associated molecular pattern (PAMP) receptors for dsRNA because of the presence of host dsRNA molecules. Thus, it is likely that most animal virus infections produce dsRNA species detectable by immunofluorescence staining, which may prove useful in viral discovery as well.
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Nellimarla S, Mossman KL. Extracellular dsRNA: its function and mechanism of cellular uptake. J Interferon Cytokine Res 2015; 34:419-26. [PMID: 24905198 DOI: 10.1089/jir.2014.0002] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Double-stranded RNA (dsRNA) is arguably the most potent viral trigger of innate immune signaling. Its activity has been recognized for over 5 decades, first as a toxin, then as a central component of the interferon system, as an efficient activator of antiviral responses and an immunomodulator for therapeutic applications. Nucleic acid sensing is the main basis for antiviral defense systems throughout the diverse forms of life from bacteria to plants and animals. Pattern recognition receptors of the host defense system not only sense viral dsRNA as a pathogen-associated molecular pattern in infected cells, but also recognize circulating endogenous dsRNA, a nonmicrobial signal, as a danger-associated molecular pattern, often leading to autoimmunity. Despite the effects of extracellular viral and host dsRNA associated with infection and autoimmunity, respectively, the understanding of cellular mechanisms for its recognition and uptake has only been appreciated in recent years. This review presents an overview of this unique form of nucleic acid, addressing its roles in infection, autoimmunity, and host sensing mechanisms. The goal of this review is to highlight the novel findings with a focus on extracellular recognition and uptake by the cell.
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Affiliation(s)
- Srinivas Nellimarla
- 1 Department of Pathology and Molecular Medicine, McMaster Immunology Research Center, Michael DeGroote Institute for Infectious Disease Research, McMaster University , Hamilton, Ontario, Canada
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34
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Collins SE, Mossman KL. Danger, diversity and priming in innate antiviral immunity. Cytokine Growth Factor Rev 2014; 25:525-31. [PMID: 25081316 DOI: 10.1016/j.cytogfr.2014.07.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 07/03/2014] [Indexed: 12/24/2022]
Abstract
The prototypic response to viral infection involves the recognition of pathogen-associated molecular patterns (PAMPs) by pattern recognition receptors (PRRs), leading to the activation of transcription factors such as IRF3 and NFkB and production of type 1 IFN. While this response can lead to the induction of hundreds of IFN-stimulated genes (ISGs) and recruitment and activation of immune cells, such a comprehensive response is likely inappropriate for routine low level virus exposure. Moreover, viruses have evolved a plethora of immune evasion strategies to subvert antiviral signalling. There is emerging evidence that cells have developed very sensitive methods of detecting not only specific viral PAMPS, but also more general danger or stress signals associated with viral entry and replication. Such stress-induced cellular responses likely serve to prime cells to respond to further PAMP stimulation or allow for a rapid and localized intracellular response independent of IFN production and its potential immune sequelae. This review discusses diversity in innate antiviral players and pathways, the role of "danger" sensing, and how alternative pathways, such as the IFN-independent pathway, may serve to prime cells for further pathogen attack.
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Affiliation(s)
- Susan E Collins
- Department of Pathology and Molecular Medicine, McMaster Immunology Research Center, Institute for Infectious Disease Research, McMaster University, Hamilton, Canada L8S 4K1
| | - Karen L Mossman
- Department of Pathology and Molecular Medicine, McMaster Immunology Research Center, Institute for Infectious Disease Research, McMaster University, Hamilton, Canada L8S 4K1.
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Abstract
UNLABELLED Replication of plus-strand RNA [(+)RNA] viruses of plants is a relatively simple process that involves complementary minus-strand RNA [(-)RNA] synthesis and subsequent (+)RNA synthesis. However, the actual replicative form of the (-)RNA template in the case of plant (+)RNA viruses is not yet established unambiguously. In this paper, using a cell-free replication assay supporting a full cycle of viral replication, we show that replication of Tomato bushy stunt virus (TBSV) leads to the formation of double-stranded RNA (dsRNA). Using RNase digestion, DNAzyme, and RNA mobility shift assays, we demonstrate the absence of naked (-)RNA templates during replication. Time course experiments showed the rapid appearance of dsRNA earlier than the bulk production of new (+)RNAs, suggesting an active role for dsRNA in replication. Radioactive nucleotide chase experiments showed that the mechanism of TBSV replication involves the use of dsRNA templates in strand displacement reactions, where the newly synthesized plus strand replaces the original (+)RNA in the dsRNA. We propose that the use of dsRNA as a template for (+)RNA synthesis by the viral replicase is facilitated by recruited host DEAD box helicases and the viral p33 RNA chaperone protein. Altogether, this replication strategy allows TBSV to separate minus- and plus-strand syntheses in time and regulate asymmetrical RNA replication that leads to abundant (+)RNA progeny. IMPORTANCE Positive-stranded RNA viruses of plants use their RNAs as the templates for replication. First, the minus strand is synthesized by the viral replicase complex (VRC), which then serves as a template for new plus-strand synthesis. To characterize the nature of the (-)RNA in the membrane-bound viral replicase, we performed complete RNA replication of Tomato bushy stunt virus (TBSV) in yeast cell-free extracts and in plant extracts. The experiments demonstrated that the TBSV (-)RNA is present as a double-stranded RNA that serves as the template for TBSV replication. During the production of new plus strands, the viral replicase displaces the old plus strand in the dsRNA template, leading to asymmetrical RNA synthesis. The presented data are in agreement with the model that the dsRNA is present in nuclease-resistant membranous VRCs. This strategy likely allows TBSV to protect the replicating viral RNA from degradation as well as to evade the early detection of viral dsRNAs by the host surveillance system.
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Lee CC, Wu CC, Lin TL. Chicken melanoma differentiation-associated gene 5 (MDA5) recognizes infectious bursal disease virus infection and triggers MDA5-related innate immunity. Arch Virol 2014; 159:1671-86. [PMID: 24452668 PMCID: PMC7086882 DOI: 10.1007/s00705-014-1983-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 11/09/2013] [Indexed: 12/24/2022]
Abstract
The objective of the present study was to determine if chicken melanoma differentiation-associated gene 5 (MDA5) senses infectious bursal disease virus (IBDV) infection to initiate and amplify an innate immune response in the chicken MDA5 (chMDA5) signaling pathway. Chicken embryo fibroblast DF-1 cells were infected with IBDV LP1 at a multiplicity of infection (MOI) of 0.5 or 10. In addition, knockdown and overexpression of chMDA5 were performed by transfecting DF-1 cells with chMDA5-targeting small interfering RNA (siRNA) or chMDA5-expressing DNA. The transfected cells were infected with IBDV LP1 at an MOI of 10. Cell culture supernatants and lysates were collected at 2, 8, 16 and 24 hours postinfection (hpi) for IBDV titer determination and RNA extraction, respectively. IBDV RNA loads and mRNA expression levels of chicken MDA5, interferon-β (IFN-β) promoter stimulator 1 (IPS-1), interferon regulatory factor-3 (IRF-3), IFN-β, double-stranded RNA-dependent protein kinase (PKR), 2′,5′-oligoadenylate synthetase (OAS), myxovirus resistance gene (Mx), and major histocompatibility complex class I (MHC class I) were determined by real-time RT-PCR. The IBDV titer increased up to 1.4 × 107 plaque-forming units (PFU)/mL at 24 hpi, and the IBDV RNA load reached 464 ng/μL at 24 hpi. The mRNA expression levels of chicken MDA5, IRF-3, IFN-β, PKR, OAS, Mx and MHC class I in IBDV-infected DF-1 cells exhibited significant (p < 0.05) upregulation up to 906-, 199-, 26,310-, 12-, 66,144-, 64,039- and 33-fold, respectively. Expressed chMDA5 from transfection and double-stranded RNA from IBDV infection were localized or colocalized in the cytoplasm of DF-1 cells at 16 hpi. When chMDA5 was knocked down in DF-1 cells, IBDV titers and RNA loads were significantly higher (p < 0.05) than those in DF-1 cells without chMDA5 knockdown at 24 hpi. The expression levels of chicken MDA5, IRF-3, IFN-β and MHC class I in chMDA5-knockdown DF-1 cells were significantly lower (p < 0.05) at 16 and 24 hpi. DF-1 cells overexpressing chMDA5 by transfection with chMDA5 expressing DNA had significantly lower (p < 0.05) IBDV titers and RNA loads at 16 and 24 hpi and showed significantly higher (p < 0.05) expression of chicken MDA5, IRF-3, IFN-β, PKR, OAS, Mx and MHC class I at 2 hpi. The results indicated that chicken MDA5 recognized IBDV infection and that this interaction resulted in the activation of chMDA5-related innate immune genes and upregulation of chicken MHC class I.
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Affiliation(s)
- Chih-Chun Lee
- Department of Comparative Pathobiology, Purdue University, 406, S. University St, West Lafayette, IN, 47907, USA
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Sokolova TM, Shuvalov AN, Telkov MV, Kolodyazhnaya LV, Ershov FI. Ridostin induces transcription of a wide spectrum of interferon genes in human cells. Bull Exp Biol Med 2013; 156:213-6. [PMID: 24319751 DOI: 10.1007/s10517-013-2313-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The effects of Ridostin on the transcription of IFN family genes in human fibroblasts and lymphocytes were studied by quantitative real-time PCR. The degree of gene induction by Ridostin was most pronounced in fibroblasts, and was significantly higher than the induction by Kagocel: transcription of IFN-β, oligoadenylate synthetase, and double-stranded RNA-dependent protein kinase genes increased by about 2000, 100, and 20 times, respectively. In lymphocytes, Ridostin also activated a wide variety of IFN family genes, including genes of IFN-β, IFN-γ, and IFN-dependent enzymes, but this induction was less pronounced than in the fibroblasts. It was shown that gene response in lymphocyte from a child with cancer is reduced in comparison with that of adult healthy participant. Ridostin, and even more so Reaferon up-regulated activities of β-actin, glycerophosphate dehydrogenase, and β2-microglobulin genes, thus making impossible or limiting their use as constitutive stable reference genes (standards) in PCR-assays of IFN and their inductors.
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Affiliation(s)
- T M Sokolova
- N. F. Gamalea Institute of Epidemiology and Microbiology, Ministry of Health of the Russian Federation; D. I. Ivanoskii Institute of Virology, Ministry of Health of the Russian Federation, Moscow, Russia.
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Zinzula L, Tramontano E. Strategies of highly pathogenic RNA viruses to block dsRNA detection by RIG-I-like receptors: hide, mask, hit. Antiviral Res 2013; 100:615-35. [PMID: 24129118 PMCID: PMC7113674 DOI: 10.1016/j.antiviral.2013.10.002] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 09/24/2013] [Accepted: 10/04/2013] [Indexed: 12/24/2022]
Abstract
dsRNA species are byproducts of RNA virus replication and/or transcription. Prompt detection of dsRNA by RIG-I like receptors (RLRs) is a hallmark of the innate immune response. RLRs activation triggers production of the type I interferon (IFN)-based antiviral response. Highly pathogenic RNA viruses encode proteins that block the RLRs pathway. Hide, mask and hit are 3 strategies of RNA viruses to avoid immune system activation.
Double-stranded RNA (dsRNA) is synthesized during the course of infection by RNA viruses as a byproduct of replication and transcription and acts as a potent trigger of the host innate antiviral response. In the cytoplasm of the infected cell, recognition of the presence of viral dsRNA as a signature of “non-self” nucleic acid is carried out by RIG-I-like receptors (RLRs), a set of dedicated helicases whose activation leads to the production of type I interferon α/β (IFN-α/β). To overcome the innate antiviral response, RNA viruses encode suppressors of IFN-α/β induction, which block RLRs recognition of dsRNA by means of different mechanisms that can be categorized into: (i) dsRNA binding and/or shielding (“hide”), (ii) dsRNA termini processing (“mask”) and (iii) direct interaction with components of the RLRs pathway (“hit”). In light of recent functional, biochemical and structural findings, we review the inhibition mechanisms of RLRs recognition of dsRNA displayed by a number of highly pathogenic RNA viruses with different disease phenotypes such as haemorrhagic fever (Ebola, Marburg, Lassa fever, Lujo, Machupo, Junin, Guanarito, Crimean-Congo, Rift Valley fever, dengue), severe respiratory disease (influenza, SARS, Hendra, Hantaan, Sin Nombre, Andes) and encephalitis (Nipah, West Nile).
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Affiliation(s)
- Luca Zinzula
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella di Monserrato, SS554, 09042 Monserrato (Cagliari), Italy.
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La Frazia S, Ciucci A, Arnoldi F, Coira M, Gianferretti P, Angelini M, Belardo G, Burrone OR, Rossignol JF, Santoro MG. Thiazolides, a new class of antiviral agents effective against rotavirus infection, target viral morphogenesis, inhibiting viroplasm formation. J Virol 2013; 87:11096-106. [PMID: 23926336 PMCID: PMC3807293 DOI: 10.1128/jvi.01213-13] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 07/29/2013] [Indexed: 12/31/2022] Open
Abstract
Rotaviruses, nonenveloped viruses presenting a distinctive triple-layered particle architecture enclosing a segmented double-stranded RNA genome, exhibit a unique morphogenetic pathway requiring the formation of cytoplasmic inclusion bodies called viroplasms in a process involving the nonstructural viral proteins NSP5 and NSP2. In these structures the concerted packaging and replication of the 11 positive-polarity single-stranded RNAs take place to generate the viral double-stranded RNA (dsRNA) genomic segments. Rotavirus infection is a leading cause of gastroenteritis-associated severe morbidity and mortality in young children, but no effective antiviral therapy exists. Herein we investigate the antirotaviral activity of the thiazolide anti-infective nitazoxanide and reveal a novel mechanism by which thiazolides act against rotaviruses. Nitazoxanide and its active circulating metabolite, tizoxanide, inhibit simian A/SA11-G3P[2] and human Wa-G1P[8] rotavirus replication in different types of cells with 50% effective concentrations (EC50s) ranging from 0.3 to 2 μg/ml and 50% cytotoxic concentrations (CC50s) higher than 50 μg/ml. Thiazolides do not affect virus infectivity, binding, or entry into target cells and do not cause a general inhibition of viral protein expression, whereas they reduce the size and alter the architecture of viroplasms, decreasing rotavirus dsRNA formation. As revealed by protein/protein interaction analysis, confocal immunofluorescence microscopy, and viroplasm-like structure formation analysis, thiazolides act by hindering the interaction between the nonstructural proteins NSP5 and NSP2. Altogether the results indicate that thiazolides inhibit rotavirus replication by interfering with viral morphogenesis and may represent a novel class of antiviral drugs effective against rotavirus gastroenteritis.
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Affiliation(s)
- Simone La Frazia
- Department of Biology, University of Rome Tor Vergata, Rome, Italy
| | | | - Francesca Arnoldi
- Department of Medicine, Surgery and Health Sciences, University of Trieste, Trieste, Italy
| | - Maurizio Coira
- Department of Biology, University of Rome Tor Vergata, Rome, Italy
| | | | - Mara Angelini
- Department of Biology, University of Rome Tor Vergata, Rome, Italy
| | - Giuseppe Belardo
- Department of Biology, University of Rome Tor Vergata, Rome, Italy
| | - Oscar R. Burrone
- International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
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Novel paradigms of innate immune sensing of viral infections. Cytokine 2013; 63:219-24. [DOI: 10.1016/j.cyto.2013.06.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 06/01/2013] [Indexed: 12/15/2022]
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Mian MF, Ahmed AN, Rad M, Babaian A, Bowdish D, Ashkar AA. Length of dsRNA (poly I:C) drives distinct innate immune responses, depending on the cell type. J Leukoc Biol 2013; 94:1025-36. [PMID: 23911868 DOI: 10.1189/jlb.0312125] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Poly I:C, a synthetic dsRNA analogue, has been used extensively for decades to study innate responses in vivo and in different cell types. We have found substantial variability while using poly I:C from different sources. In this study we found that poly I:C from 2 commercial sources induced sharply opposite responses in myeloid and fibroblasts, depending on the length of the poly I:C. Although short poly I:C (≈ 1-1.5 kb) induced greater amounts of TNF-α, IL-8, and IFN-β and a stronger antiviral response in myeloid cells, it was a poor inducer in fibroblasts. By contrast, long poly I:C (>5 kb) preferentially elicited higher cytokine and antiviral responses in fibroblasts and showed diminished responses in myeloid cells. Poly I:C activated NF-κB and STAT-1 signaling in a length- and cell-type-dependent fashion. Mechanistically, short poly I:C was better internalized in the myeloid cells and long poly I:C in the fibroblasts. Finally, long poly I:C required SR-A, whereas short poly I:C required RIG-I and Raftlin. We provide evidence that the length of dsRNA drives distinct innate responses in different cell lineages. These findings may augment in selecting the appropriate poly I:C type to design cell-type-specific potent adjuvants for vaccines against infectious diseases or cancers.
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Affiliation(s)
- M Firoz Mian
- 2.Department of Pathology and Molecular Medicine, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada.
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Park H, Serti E, Eke O, Muchmore B, Prokunina-Olsson L, Capone S, Folgori A, Rehermann B. IL-29 is the dominant type III interferon produced by hepatocytes during acute hepatitis C virus infection. Hepatology 2012; 56:2060-70. [PMID: 22706965 PMCID: PMC3581145 DOI: 10.1002/hep.25897] [Citation(s) in RCA: 112] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Accepted: 05/30/2012] [Indexed: 12/15/2022]
Abstract
UNLABELLED Early, vigorous intrahepatic induction of interferon (IFN)-stimulated gene (ISG) induction is a feature of hepatitis C virus (HCV) infection, even though HCV inhibits the induction of type I IFNs in vitro. To identify the cytokines and cells that drive ISG induction and mediate antiviral activity during acute HCV infection, type I and III IFN responses were studied in (1) serial liver biopsies and plasma samples obtained from 6 chimpanzees throughout acute HCV infection and (2) primary human hepatocyte (PHH) cultures upon HCV infection. Type I IFNs were minimally induced at the messenger RNA (mRNA) level in the liver and were undetectable at the protein level in plasma during acute HCV infection of chimpanzees. In contrast, type III IFNs, in particular, interleukin (IL)-29 mRNA and protein, were strongly induced and these levels correlated with ISG expression and viremia. However, there was no association between intrahepatic or peripheral type III IFN levels and the outcome of acute HCV infection. Infection of PHH with HCV recapitulated strong type III and weak type I IFN responses. Supernatants from HCV-infected PHH cultures mediated antiviral activity upon transfer to HCV-replicon-containing cells. This effect was significantly reduced by neutralization of type III IFNs and less by neutralization of type I IFNs. Furthermore, IL-29 production by HCV-infected PHH occurred independently from type I IFN signaling and was not enhanced by the presence of plasmacytoid dendritic cells. CONCLUSION Hepatocyte-derived type III IFNs contribute to ISG induction and antiviral activity, but are not the principal determinant of the outcome of HCV infection.
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Affiliation(s)
- Heiyoung Park
- Immunology Section, Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Bethesda, MD
| | - Elisavet Serti
- Immunology Section, Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Bethesda, MD
| | - Onyinyechi Eke
- Immunology Section, Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Bethesda, MD
| | - Brian Muchmore
- Laboratory of Translational Genomics, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, MD
| | - Ludmila Prokunina-Olsson
- Laboratory of Translational Genomics, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, MD
| | | | | | - Barbara Rehermann
- Immunology Section, Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Bethesda, MD
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Cherepanova AV, Bushuev AV, Kharkova MV, Vlassov VV, Laktionov PP. DNA inhibits dsRNA-induced secretion of pro-inflammatory cytokines by gingival fibroblasts. Immunobiology 2012; 218:272-80. [PMID: 22749216 DOI: 10.1016/j.imbio.2012.05.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 04/09/2012] [Accepted: 05/16/2012] [Indexed: 01/05/2023]
Abstract
Nucleic acids interacting with pattern-recognizing receptors (PRRs), such as Toll-like-(TLRs), RIG-I-like receptors (RLRs) and dsDNA-receptors activate innate immune response in non-professional immune cells and thus the production of pro-inflammatory cytokines. Along with bacterial and viral nucleic acids, endogenous cell-free and cell-surface-bound extracellular DNA (exDNA and csbDNA) could interact with PRRs and possess immunomodulating activity. To elucidate if exDNA influence innate immunity a comparative study of exDNA, genomic and plasmid DNA on interleukin production in gingival fibroblasts (GF) has been done. All DNA tested have no effect on IL secretion in a broad concentration range (10 ng/ml-1 μg/ml). Simultaneous treatment of cells with DNA and dsRNA analog poly(I:C) leads to inhibition of poly(I:C)-activated secretion of IL-6 and IL-8. Cell-surface-bound DNA possesses two times stronger inhibiting effect as compared to genomic DNA indicating the enrichment of csbDNA in sequences providing such activity. Effects of several recently found specific DNA sequences tightly bound with cell surface have been tested. Joint stimulation of GF with poly(I:C) and deoxyribooligonucleotides (ODN), containing such sequences, demonstrates that both ssODN and dsODN possess sequence-dependent inhibiting effect. Inhibition of IL production after colipofection of ODN and poly(I:C) into cells indicates the involvement of RLRs or other cytoplasmic factors in the effect. The data obtained indicate that endogenous DNA might be involved in regulation of antiviral immune response and sequence-specific ODNs are potential inhibitors of the inflammation induced by viral infection.
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Affiliation(s)
- Anna V Cherepanova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Division of the Russian Academy of Sciences, Novosibirsk 630090, Russia.
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Pulit-Penaloza JA, Scherbik SV, Brinton MA. Type 1 IFN-independent activation of a subset of interferon stimulated genes in West Nile virus Eg101-infected mouse cells. Virology 2012; 425:82-94. [PMID: 22305622 PMCID: PMC3288888 DOI: 10.1016/j.virol.2012.01.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Revised: 10/10/2011] [Accepted: 01/09/2012] [Indexed: 12/24/2022]
Abstract
Although infection of mouse embryofibroblasts (MEFs) with WNV Eg101 induced interferon (IFN) beta production and STAT1 and STAT2 phosphorylation, these transcription factors (TFs) were not detected in the nucleus or on the promoters of four IRF-3-independent interferon stimulated genes (ISGs): Oas1a and Irf7 (previously characterized as IFN/ISGF3-dependent), Oas1b and Irf1. These ISGs were upregulated in WNV Eg101-infected STAT1-/-, STAT2-/-, and IFN alpha/beta receptor-/- MEFs. Although either IRF-3 or IRF-7 could amplify/sustain Oas1a and Oas1b upregulation at later times after infection, these factors were not required for the initial gene activation. The lack of upregulation of these ISGs in WNV Eg101-infected IRF-3/9-/- MEFs suggested the involvement of IRF-9. Activation of Irf1 in infected MEFs did not depend on any of these IRFs. The data indicate that additional alternative activation mechanisms exist for subsets of ISGs when a virus infection has blocked ISG activation by the canonical IFN-mediated pathway.
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Affiliation(s)
| | | | - Margo A. Brinton
- Department of Biology, Georgia State University, Atlanta, Georgia 30302
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Mehta DR, Ashkar AA, Mossman KL. The nitric oxide pathway provides innate antiviral protection in conjunction with the type I interferon pathway in fibroblasts. PLoS One 2012; 7:e31688. [PMID: 22363706 PMCID: PMC3283670 DOI: 10.1371/journal.pone.0031688] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Accepted: 01/11/2012] [Indexed: 12/30/2022] Open
Abstract
The innate host response to virus infection is largely dominated by the production of type I interferon and interferon stimulated genes. In particular, fibroblasts respond robustly to viral infection and to recognition of viral signatures such as dsRNA with the rapid production of type I interferon; subsequently, fibroblasts are a key cell type in antiviral protection. We recently found, however, that primary fibroblasts deficient for the production of interferon, interferon stimulated genes, and other cytokines and chemokines mount a robust antiviral response against both DNA and RNA viruses following stimulation with dsRNA. Nitric oxide is a chemical compound with pleiotropic functions; its production by phagocytes in response to interferon-γ is associated with antimicrobial activity. Here we show that in response to dsRNA, nitric oxide is rapidly produced in primary fibroblasts. In the presence of an intact interferon system, nitric oxide plays a minor but significant role in antiviral protection. However, in the absence of an interferon system, nitric oxide is critical for the protection against DNA viruses. In primary fibroblasts, NF-κB and interferon regulatory factor 1 participate in the induction of inducible nitric oxide synthase expression, which subsequently produces nitric oxide. As large DNA viruses encode multiple and diverse immune modulators to disable the interferon system, it appears that the nitric oxide pathway serves as a secondary strategy to protect the host against viral infection in key cell types, such as fibroblasts, that largely rely on the type I interferon system for antiviral protection.
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Affiliation(s)
- Devangi R. Mehta
- Department of Pathology and Molecular Medicine, McMaster Immunology Research Centre, Michael DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Ali A. Ashkar
- Department of Pathology and Molecular Medicine, McMaster Immunology Research Centre, Michael DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Karen L. Mossman
- Department of Pathology and Molecular Medicine, McMaster Immunology Research Centre, Michael DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
- * E-mail:
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ACBD3-mediated recruitment of PI4KB to picornavirus RNA replication sites. EMBO J 2011; 31:754-66. [PMID: 22124328 DOI: 10.1038/emboj.2011.429] [Citation(s) in RCA: 137] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Accepted: 10/31/2011] [Indexed: 01/11/2023] Open
Abstract
Phosphatidylinositol 4-kinase IIIβ (PI4KB) is a host factor required for genome RNA replication of enteroviruses, small non-enveloped viruses belonging to the family Picornaviridae. Here, we demonstrated that PI4KB is also essential for genome replication of another picornavirus, Aichi virus (AiV), but is recruited to the genome replication sites by a different strategy from that utilized by enteroviruses. AiV non-structural proteins, 2B, 2BC, 2C, 3A, and 3AB, interacted with a Golgi protein, acyl-coenzyme A binding domain containing 3 (ACBD3). Furthermore, we identified previously unknown interaction between ACBD3 and PI4KB, which provides a novel manner of Golgi recruitment of PI4KB. Knockdown of ACBD3 or PI4KB suppressed AiV RNA replication. The viral proteins, ACBD3, PI4KB, and phophatidylinositol-4-phosphate (PI4P) localized to the viral RNA replication sites. AiV replication and recruitment of PI4KB to the RNA replication sites were not affected by brefeldin A, in contrast to those in enterovirus infection. These results indicate that a viral protein/ACBD3/PI4KB complex is formed to synthesize PI4P at the AiV RNA replication sites and plays an essential role in viral RNA replication.
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Ishibashi O, Ali MM, Luo SS, Ohba T, Katabuchi H, Takeshita T, Takizawa T. Short RNA duplexes elicit RIG-I-mediated apoptosis in a cell type- and length-dependent manner. Sci Signal 2011; 4:ra74. [PMID: 22067459 DOI: 10.1126/scisignal.2001614] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Short double-stranded RNAs (dsRNAs) induce type I interferon (IFN)-mediated innate immune responses. In functional studies with short interfering RNAs or synthetic mimics of microRNA precursors in vitro, we found that short dsRNAs readily induced apoptosis in cells derived from human granulosa cell tumors, but not in other cell types. Apoptosis was independent of the sequence of the dsRNA, but depended on its length, and was induced by 23- and 24-nucleotide (nt) dsRNAs, but not by shorter dsRNAs (< 22 nt) or by the long dsRNA polyinosinic-polycytidylic acid. Microarray analysis revealed that apoptosis was accompanied by the increased expression of IFN-stimulated genes; however, several lines of evidence showed that IFNs did not directly induce apoptosis. Subsequent analyses revealed that the short dsRNAs increased the expression of retinoic acid-inducible gene I (RIG-I) through dsRNA-activated protein kinase (PKR). Although these dsRNAs bore 3' overhangs and nontriphosphate 5' termini, which are not thought to be RIG-I-activating structures, the dsRNAs bound to RIG-I and triggered proapoptotic signaling mostly by activating RIG-I, which was followed by activation of the mitogen-activated protein kinase p38. Thus, we suggest that ligand recognition and subsequent signaling by RNA sensors are more complicated than previously believed. In addition, short dsRNAs may serve as pharmacological agents to target specific tumors, such as granulosa cell tumors.
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Affiliation(s)
- Osamu Ishibashi
- Department of Molecular Medicine and Anatomy, Nippon Medical School, 1-1-5 Sendagi, Tokyo 113-8602, Japan
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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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Membrane perturbation elicits an IRF3-dependent, interferon-independent antiviral response. J Virol 2011; 85:10926-31. [PMID: 21813605 DOI: 10.1128/jvi.00862-11] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
We previously found that enveloped virus binding and penetration are necessary to initiate an interferon-independent, IRF3-mediated antiviral response. To investigate whether membrane perturbations that accompany membrane fusion-dependent enveloped-virus entry are necessary and sufficient for antiviral-state induction, we utilized a reovirus fusion-associated small transmembrane (FAST) protein. Membrane disturbances during FAST protein-mediated fusion, in the absence of additional innate immune response triggers, are sufficient to elicit interferon-stimulated gene induction and establishment of an antiviral state. Using sensors of membrane disruption to activate an IRF3-dependent, interferon-independent antiviral state may provide cells with a rapid, broad-spectrum innate immune response to enveloped-virus infections.
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Jiang M, Osterlund P, Sarin LP, Poranen MM, Bamford DH, Guo D, Julkunen I. Innate immune responses in human monocyte-derived dendritic cells are highly dependent on the size and the 5' phosphorylation of RNA molecules. THE JOURNAL OF IMMUNOLOGY 2011; 187:1713-21. [PMID: 21742966 DOI: 10.4049/jimmunol.1100361] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Recognition of viral genetic material takes place via several different receptor systems, such as retinoic acid-inducible gene I-like receptors and TLRs 3, 7, 8, and 9. At present, systematic comparison of the ability of different types of RNAs to induce innate immune responses in human immune cells has been limited. In this study, we generated bacteriophage 6 and influenza A virus-specific ssRNA and dsRNA molecules ranging from 58 to 2956 nt. In human monocyte-derived dendritic cells (moDCs), short dsRNAs efficiently upregulated the expression of IFN (IFN-α, IFN-β, and IFN-λ1) and proinflammatory (TNF-α, IL-6, IL-12, and CXCL10) cytokine genes. These genes were also induced by ssRNA molecules, but size-specific differences were not as pronounced as with dsRNA molecules. Dephosphorylation of short ssRNA and dsRNA molecules led to a dramatic reduction in their ability to stimulate innate immune responses. Such a difference was not detected for long ssRNAs. RNA-induced cytokine responses correlated well with IFN regulatory factor 3 phosphorylation, suggesting that IFN regulatory factor 3 plays a major role in both ssRNA- and dsRNA-activated responses in human moDCs. We also found that IFN gene expression was efficiently stimulated following recognition of short dsRNAs by retinoic acid-inducible gene I and TLR3 in human embryonic kidney 293 cells, whereas ssRNA-induced responses were less dependent on the size of the RNA molecule. Our data suggest that human moDCs are extremely sensitive in recognizing foreign RNA, and the responses depend on RNA size, form (ssRNA versus dsRNA), and the level of 5' phosphorylation.
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Affiliation(s)
- Miao Jiang
- National Key Laboratory of Virology and Modern Virology Research Center, College of Life Sciences, Wuhan University, Wuhan 430072, China
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