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Velez-Brochero M, Behera P, Afreen KS, Odle A, Rajsbaum R. Ubiquitination in viral entry and replication: Mechanisms and implications. Adv Virus Res 2024; 119:1-38. [PMID: 38897707 DOI: 10.1016/bs.aivir.2024.05.001] [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] [Indexed: 06/21/2024]
Abstract
The ubiquitination process is a reversible posttranslational modification involved in many essential cellular functions, such as innate immunity, cell signaling, trafficking, protein stability, and protein degradation. Viruses can use the ubiquitin system to efficiently enter host cells, replicate and evade host immunity, ultimately enhancing viral pathogenesis. Emerging evidence indicates that enveloped viruses can carry free (unanchored) ubiquitin or covalently ubiquitinated viral structural proteins that can increase the efficiency of viral entry into host cells. Furthermore, viruses continuously evolve and adapt to take advantage of the host ubiquitin machinery, highlighting its importance during virus infection. This review discusses the battle between viruses and hosts, focusing on how viruses hijack the ubiquitination process at different steps of the replication cycle, with a specific emphasis on viral entry. We discuss how ubiquitination of viral proteins may affect tropism and explore emerging therapeutics strategies targeting the ubiquitin system for antiviral drug discovery.
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Affiliation(s)
- Maria Velez-Brochero
- Center for Virus-Host-Innate Immunity and Department of Medicine, Rutgers Biomedical and Health Sciences, Institute for Infectious and Inflammatory Diseases, Rutgers University, Newark, NJ, United States
| | - Padmanava Behera
- Center for Virus-Host-Innate Immunity and Department of Medicine, Rutgers Biomedical and Health Sciences, Institute for Infectious and Inflammatory Diseases, Rutgers University, Newark, NJ, United States
| | - Kazi Sabrina Afreen
- Center for Virus-Host-Innate Immunity and Department of Medicine, Rutgers Biomedical and Health Sciences, Institute for Infectious and Inflammatory Diseases, Rutgers University, Newark, NJ, United States
| | - Abby Odle
- Center for Virus-Host-Innate Immunity and Department of Medicine, Rutgers Biomedical and Health Sciences, Institute for Infectious and Inflammatory Diseases, Rutgers University, Newark, NJ, United States
| | - Ricardo Rajsbaum
- Center for Virus-Host-Innate Immunity and Department of Medicine, Rutgers Biomedical and Health Sciences, Institute for Infectious and Inflammatory Diseases, Rutgers University, Newark, NJ, United States.
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Collados Rodríguez M, Maillard P, Journeaux A, Komarova AV, Najburg V, David RYS, Helynck O, Guo M, Zhong J, Baize S, Tangy F, Jacob Y, Munier-Lehmann H, Meurs EF. Novel Antiviral Molecules against Ebola Virus Infection. Int J Mol Sci 2023; 24:14791. [PMID: 37834238 PMCID: PMC10573436 DOI: 10.3390/ijms241914791] [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: 08/30/2023] [Revised: 09/19/2023] [Accepted: 09/22/2023] [Indexed: 10/15/2023] Open
Abstract
Infection with Ebola virus (EBOV) is responsible for hemorrhagic fever in humans with a high mortality rate. Combined efforts of prevention and therapeutic intervention are required to tackle highly variable RNA viruses, whose infections often lead to outbreaks. Here, we have screened the 2P2I3D chemical library using a nanoluciferase-based protein complementation assay (NPCA) and isolated two compounds that disrupt the interaction of the EBOV protein fragment VP35IID with the N-terminus of the dsRNA-binding proteins PKR and PACT, involved in IFN response and/or intrinsic immunity, respectively. The two compounds inhibited EBOV infection in cell culture as well as infection by measles virus (MV) independently of IFN induction. Consequently, we propose that the compounds are antiviral by restoring intrinsic immunity driven by PACT. Given that PACT is highly conserved across mammals, our data support further testing of the compounds in other species, as well as against other negative-sense RNA viruses.
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Affiliation(s)
- Mila Collados Rodríguez
- School of Infection & Immunity (SII), College of Medical, Veterinary and Life Sciences (MVLS), Sir Michael Stoker Building, MRC-University of Glasgow Centre for Virus Research (CVR), Glasgow G61 1QH, UK
- Unité Hépacivirus et Immunité Innée, CNRS, UMR 3569, Département de Virologie, Institut Pasteur, 75015 Paris, France; (P.M.); (E.F.M.)
| | - Patrick Maillard
- Unité Hépacivirus et Immunité Innée, CNRS, UMR 3569, Département de Virologie, Institut Pasteur, 75015 Paris, France; (P.M.); (E.F.M.)
| | - Alexandra Journeaux
- Unit of Biology of Emerging Viral Infections, Institut Pasteur, 69007 Lyon, France; (A.J.); (S.B.)
| | - Anastassia V. Komarova
- Interactomics, RNA and Immunity Laboratory, Institut Pasteur, 75015 Paris, France;
- Unité de Génomique Virale et Vaccination, Institut Pasteur, 75015 Paris, France; (V.N.); (R.-Y.S.D.); (F.T.)
- Université Paris Cité, 75013 Paris, France;
| | - Valérie Najburg
- Unité de Génomique Virale et Vaccination, Institut Pasteur, 75015 Paris, France; (V.N.); (R.-Y.S.D.); (F.T.)
- Université Paris Cité, 75013 Paris, France;
| | - Raul-Yusef Sanchez David
- Unité de Génomique Virale et Vaccination, Institut Pasteur, 75015 Paris, France; (V.N.); (R.-Y.S.D.); (F.T.)
- Blizard Institute—Faculty of Medicine and Dentistry, Queen Mary University of London, London E1 2AT, UK
| | - Olivier Helynck
- Unité de Chimie et Biocatalyse, CNRS, UMR 3523, Institut Pasteur, Université de Paris, 75015 Paris, France; (O.H.); (H.M.-L.)
| | - Mingzhe Guo
- CAS Key Laboratory of Molecular Virology and Immunology, Unit of Viral Hepatitis, Shanghai Institute of Immunity and Infection, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Shanghai 200023, China; (M.G.); (J.Z.)
| | - Jin Zhong
- CAS Key Laboratory of Molecular Virology and Immunology, Unit of Viral Hepatitis, Shanghai Institute of Immunity and Infection, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Shanghai 200023, China; (M.G.); (J.Z.)
| | - Sylvain Baize
- Unit of Biology of Emerging Viral Infections, Institut Pasteur, 69007 Lyon, France; (A.J.); (S.B.)
| | - Frédéric Tangy
- Unité de Génomique Virale et Vaccination, Institut Pasteur, 75015 Paris, France; (V.N.); (R.-Y.S.D.); (F.T.)
- Université Paris Cité, 75013 Paris, France;
| | - Yves Jacob
- Université Paris Cité, 75013 Paris, France;
- Unité Génétique Moléculaire des Virus à ARN, CNRS, UMR 3569, Département de Virologie, Institut Pasteur, 75015 Paris, France
| | - Hélène Munier-Lehmann
- Unité de Chimie et Biocatalyse, CNRS, UMR 3523, Institut Pasteur, Université de Paris, 75015 Paris, France; (O.H.); (H.M.-L.)
| | - Eliane F. Meurs
- Unité Hépacivirus et Immunité Innée, CNRS, UMR 3569, Département de Virologie, Institut Pasteur, 75015 Paris, France; (P.M.); (E.F.M.)
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Escudero-Pérez B, Lalande A, Mathieu C, Lawrence P. Host–Pathogen Interactions Influencing Zoonotic Spillover Potential and Transmission in Humans. Viruses 2023; 15:v15030599. [PMID: 36992308 PMCID: PMC10060007 DOI: 10.3390/v15030599] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 02/13/2023] [Accepted: 02/20/2023] [Indexed: 02/24/2023] Open
Abstract
Emerging infectious diseases of zoonotic origin are an ever-increasing public health risk and economic burden. The factors that determine if and when an animal virus is able to spill over into the human population with sufficient success to achieve ongoing transmission in humans are complex and dynamic. We are currently unable to fully predict which pathogens may appear in humans, where and with what impact. In this review, we highlight current knowledge of the key host–pathogen interactions known to influence zoonotic spillover potential and transmission in humans, with a particular focus on two important human viruses of zoonotic origin, the Nipah virus and the Ebola virus. Namely, key factors determining spillover potential include cellular and tissue tropism, as well as the virulence and pathogenic characteristics of the pathogen and the capacity of the pathogen to adapt and evolve within a novel host environment. We also detail our emerging understanding of the importance of steric hindrance of host cell factors by viral proteins using a “flytrap”-type mechanism of protein amyloidogenesis that could be crucial in developing future antiviral therapies against emerging pathogens. Finally, we discuss strategies to prepare for and to reduce the frequency of zoonotic spillover occurrences in order to minimize the risk of new outbreaks.
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Affiliation(s)
- Beatriz Escudero-Pérez
- WHO Collaborating Centre for Arbovirus and Haemorrhagic Fever Reference and Research, Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany
- German Center for Infection Research (DZIF), Partner Site Hamburg-Luebeck-Borstel-Reims, 38124 Braunschweig, Germany
| | - Alexandre Lalande
- CIRI (Centre International de Recherche en Infectiologie), Team Neuro-Invasion, TROpism and VIRal Encephalitis, INSERM U1111, CNRS UMR5308, Université Claude Bernard Lyon 1, Ecole Normale Supérieure de Lyon, 69007 Lyon, France
| | - Cyrille Mathieu
- CIRI (Centre International de Recherche en Infectiologie), Team Neuro-Invasion, TROpism and VIRal Encephalitis, INSERM U1111, CNRS UMR5308, Université Claude Bernard Lyon 1, Ecole Normale Supérieure de Lyon, 69007 Lyon, France
| | - Philip Lawrence
- CONFLUENCE: Sciences et Humanités (EA 1598), Université Catholique de Lyon (UCLy), 69002 Lyon, France
- Correspondence:
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Namer LS, Harwig A, Heynen SP, Das AT, Berkhout B, Kaempfer R. HIV co-opts a cellular antiviral mechanism, activation of stress kinase PKR by its RNA, to enable splicing of rev/tat mRNA. Cell Biosci 2023; 13:28. [PMID: 36774495 PMCID: PMC9922466 DOI: 10.1186/s13578-023-00972-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 01/24/2023] [Indexed: 02/13/2023] Open
Abstract
BACKGROUND Activation of RNA-dependent stress kinase PKR, especially by viral double-stranded RNA, induces eukaryotic initiation factor 2 α-chain (eIF2α) phosphorylation, attenuating thereby translation. We report that this RNA-mediated negative control mechanism, considered a cornerstone of the cell's antiviral response, positively regulates splicing of a viral mRNA. RESULTS Excision of the large human immunodeficiency virus (HIV) rev/tat intron depends strictly on activation of PKR by the viral RNA and on eIF2α phosphorylation. Rev/tat mRNA splicing was blocked by viral PKR antagonists Vaccinia E3L and Ebola VP35, as well as by a trans-dominant negative mutant of PKR, yet enhanced by overexpressing PKR. Expression of non-phosphorylatable mutant eIF2αS51A, but not of wild type eIF2α, abrogated efficient splicing of rev/tat mRNA. By contrast, expression of eIF2αS51D, a phosphomimetic mutant of eIF2α, left rev/tat mRNA splicing intact. Unlike eIF2αS51A, eIF2αS51D does not inhibit eIF2α phosphorylation by activated PKR. All HIV mRNA species contain terminal trans-activation response (TAR) stem-loop sequences that potentially could activate PKR, yet even upon TAR deletion, HIV mRNA production remained sensitive to inhibitors of PKR activation. Bioinformatic and mutational analyses revealed a compact RNA pseudoknot upstream of 3'-terminal TAR that promotes splicing by activating PKR. Supporting its essential role in control of splicing, this pseudoknot is conserved among diverse HIV and nonhuman primate SIVcpz isolates. The pseudoknot and 3'-terminal TAR collaborate in mediating PKR-regulated splicing of rev/tat intron, the pseudoknot being dominant. CONCLUSIONS Our results on HIV provide the first example of a virus co-opting activation of PKR by its RNA, a cellular antiviral mechanism, to promote splicing. They raise the question whether other viruses may use local activation of host kinase PKR through RNA elements within their genome to achieve efficient splicing of their mRNA. Our experiments reveal an indispensable role for eIF2α phosphorylation in HIV rev/tat mRNA splicing that accounts for the need for PKR activation.
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Affiliation(s)
- Lise Sarah Namer
- grid.9619.70000 0004 1937 0538Department of Biochemistry and Molecular Biology, Institute of Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, 9112102 Jerusalem, Israel
| | - Alex Harwig
- grid.509540.d0000 0004 6880 3010Laboratory of Experimental Virology, Department of Medical Microbiology, Amsterdam UMC, 1105 AZ Amsterdam, The Netherlands
| | - Stephan P. Heynen
- grid.509540.d0000 0004 6880 3010Laboratory of Experimental Virology, Department of Medical Microbiology, Amsterdam UMC, 1105 AZ Amsterdam, The Netherlands
| | - Atze T. Das
- grid.509540.d0000 0004 6880 3010Laboratory of Experimental Virology, Department of Medical Microbiology, Amsterdam UMC, 1105 AZ Amsterdam, The Netherlands
| | - Ben Berkhout
- grid.509540.d0000 0004 6880 3010Laboratory of Experimental Virology, Department of Medical Microbiology, Amsterdam UMC, 1105 AZ Amsterdam, The Netherlands
| | - Raymond Kaempfer
- Department of Biochemistry and Molecular Biology, Institute of Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, 9112102, Jerusalem, Israel.
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Escudero-Pérez B, Lawrence P, Castillo-Olivares J. Immune correlates of protection for SARS-CoV-2, Ebola and Nipah virus infection. Front Immunol 2023; 14:1156758. [PMID: 37153606 PMCID: PMC10158532 DOI: 10.3389/fimmu.2023.1156758] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 03/20/2023] [Indexed: 05/09/2023] Open
Abstract
Correlates of protection (CoP) are biological parameters that predict a certain level of protection against an infectious disease. Well-established correlates of protection facilitate the development and licensing of vaccines by assessing protective efficacy without the need to expose clinical trial participants to the infectious agent against which the vaccine aims to protect. Despite the fact that viruses have many features in common, correlates of protection can vary considerably amongst the same virus family and even amongst a same virus depending on the infection phase that is under consideration. Moreover, the complex interplay between the various immune cell populations that interact during infection and the high degree of genetic variation of certain pathogens, renders the identification of immune correlates of protection difficult. Some emerging and re-emerging viruses of high consequence for public health such as SARS-CoV-2, Nipah virus (NiV) and Ebola virus (EBOV) are especially challenging with regards to the identification of CoP since these pathogens have been shown to dysregulate the immune response during infection. Whereas, virus neutralising antibodies and polyfunctional T-cell responses have been shown to correlate with certain levels of protection against SARS-CoV-2, EBOV and NiV, other effector mechanisms of immunity play important roles in shaping the immune response against these pathogens, which in turn might serve as alternative correlates of protection. This review describes the different components of the adaptive and innate immune system that are activated during SARS-CoV-2, EBOV and NiV infections and that may contribute to protection and virus clearance. Overall, we highlight the immune signatures that are associated with protection against these pathogens in humans and could be used as CoP.
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Affiliation(s)
- Beatriz Escudero-Pérez
- WHO Collaborating Centre for Arbovirus and Haemorrhagic Fever Reference and Research, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- German Center for Infection Research (DZIF), Partner Site Hamburg-Luebeck-Borstel-Reims, Braunschweig, Germany
- *Correspondence: Beatriz Escudero-Pérez, ; Javier Castillo-Olivares,
| | - Philip Lawrence
- CONFLUENCE: Sciences et Humanités (EA 1598), Université Catholique de Lyon (UCLy), Lyon, France
| | - Javier Castillo-Olivares
- Laboratory of Viral Zoonotics, University of Cambridge, Cambridge, United Kingdom
- *Correspondence: Beatriz Escudero-Pérez, ; Javier Castillo-Olivares,
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Wu C, Holehouse AS, Leung DW, Amarasinghe GK, Dutch RE. Liquid Phase Partitioning in Virus Replication: Observations and Opportunities. Annu Rev Virol 2022; 9:285-306. [PMID: 35709511 DOI: 10.1146/annurev-virology-093020-013659] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Viruses frequently carry out replication in specialized compartments within cells. The effect of these structures on virus replication is poorly understood. Recent research supports phase separation as a foundational principle for organization of cellular components with the potential to influence viral replication. In this review, phase separation is described in the context of formation of viral replication centers, with an emphasis on the nonsegmented negative-strand RNA viruses. Consideration is given to the interplay between phase separation and the critical processes of viral transcription and genome replication, and the role of these regions in pathogen-host interactions is discussed. Finally, critical questions that must be addressed to fully understand how phase separation influences viral replication and the viral life cycle are presented, along with information about new approaches that could be used to make important breakthroughs in this emerging field.
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Affiliation(s)
- Chao Wu
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Alex S Holehouse
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
- Center for Science and Engineering Living Systems, Washington University, St. Louis, Missouri, USA
| | - Daisy W Leung
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Gaya K Amarasinghe
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Rebecca Ellis Dutch
- Department of Molecular and Cellular Biochemistry, University of Kentucky, College of Medicine, Lexington, Kentucky, USA;
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7
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Fang J, Pietzsch C, Tsaprailis G, Crynen G, Cho KF, Ting AY, Bukreyev A, de la Torre JC, Saphire EO. Functional interactomes of the Ebola virus polymerase identified by proximity proteomics in the context of viral replication. Cell Rep 2022; 38:110544. [PMID: 35320713 PMCID: PMC10496643 DOI: 10.1016/j.celrep.2022.110544] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 12/26/2021] [Accepted: 03/01/2022] [Indexed: 11/21/2022] Open
Abstract
Ebola virus (EBOV) critically depends on the viral polymerase to replicate and transcribe the viral RNA genome in the cytoplasm of host cells, where cellular factors can antagonize or facilitate the virus life cycle. Here we leverage proximity proteomics and conduct a small interfering RNA (siRNA) screen to define the functional interactome of EBOV polymerase. As a proof of principle, we validate two cellular mRNA decay factors from 35 identified host factors: eukaryotic peptide chain release factor subunit 3a (eRF3a/GSPT1) and up-frameshift protein 1 (UPF1). Our data suggest that EBOV can subvert restrictions of cellular mRNA decay and repurpose GSPT1 and UPF1 to promote viral replication. Treating EBOV-infected human hepatocytes with a drug candidate that targets GSPT1 for degradation significantly reduces viral RNA load and particle production. Our work demonstrates the utility of proximity proteomics to capture the functional host interactome of the EBOV polymerase and to illuminate host-dependent regulation of viral RNA synthesis.
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Affiliation(s)
- Jingru Fang
- La Jolla Institute for Immunology, La Jolla, CA 92037, USA; Department of Immunology and Microbiology, Scripps Research, La Jolla, CA 92037, USA
| | - Colette Pietzsch
- Department of Pathology and Galveston National Laboratory, University of Texas Medical Branch, Galveston, TX 77555, USA
| | | | - Gogce Crynen
- Bioinformatics and Statistics Core, Scripps Research, Jupiter, FL 33458, USA
| | - Kelvin Frank Cho
- Cancer Biology Program, Stanford University, Stanford, CA 94305, USA
| | - Alice Y Ting
- Department of Genetics, Department of Biology, and Department of Chemistry, Stanford University, Stanford, CA 94305, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA
| | - Alexander Bukreyev
- Department of Pathology and Galveston National Laboratory, University of Texas Medical Branch, Galveston, TX 77555, USA; Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77550, USA.
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Miorin L, Mire CE, Ranjbar S, Hume AJ, Huang J, Crossland NA, White KM, Laporte M, Kehrer T, Haridas V, Moreno E, Nambu A, Jangra S, Cupic A, Dejosez M, Abo KA, Tseng AE, Werder RB, Rathnasinghe R, Mutetwa T, Ramos I, de Aja JS, de Alba Rivas CG, Schotsaert M, Corley RB, Falvo JV, Fernandez-Sesma A, Kim C, Rossignol JF, Wilson AA, Zwaka T, Kotton DN, Mühlberger E, García-Sastre A, Goldfeld AE. The oral drug nitazoxanide restricts SARS-CoV-2 infection and attenuates disease pathogenesis in Syrian hamsters. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2022:2022.02.08.479634. [PMID: 35169796 PMCID: PMC8845418 DOI: 10.1101/2022.02.08.479634] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
A well-tolerated and cost-effective oral drug that blocks SARS-CoV-2 growth and dissemination would be a major advance in the global effort to reduce COVID-19 morbidity and mortality. Here, we show that the oral FDA-approved drug nitazoxanide (NTZ) significantly inhibits SARS-CoV-2 viral replication and infection in different primate and human cell models including stem cell-derived human alveolar epithelial type 2 cells. Furthermore, NTZ synergizes with remdesivir, and it broadly inhibits growth of SARS-CoV-2 variants B.1.351 (beta), P.1 (gamma), and B.1617.2 (delta) and viral syncytia formation driven by their spike proteins. Strikingly, oral NTZ treatment of Syrian hamsters significantly inhibits SARS-CoV-2-driven weight loss, inflammation, and viral dissemination and syncytia formation in the lungs. These studies show that NTZ is a novel host-directed therapeutic that broadly inhibits SARS-CoV-2 dissemination and pathogenesis in human and hamster physiological models, which supports further testing and optimization of NTZ-based therapy for SARS-CoV-2 infection alone and in combination with antiviral drugs.
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9
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Yamaoka S, Ebihara H. Pathogenicity and Virulence of Ebolaviruses with Species- and Variant-specificity. Virulence 2021; 12:885-901. [PMID: 33734027 PMCID: PMC7993122 DOI: 10.1080/21505594.2021.1898169] [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] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 02/10/2021] [Accepted: 02/19/2021] [Indexed: 01/05/2023] Open
Abstract
Ebola virus (EBOV), belonging to the species Zaire ebolavirus in the genus Ebolavirus, causes a severe febrile illness in humans with case fatality rates (CFRs) up to 90%. While there have been six virus species classified, which each have a single type virus in the genus Ebolavirus, CFRs of ebolavirus infections vary among viruses belonging to each distinct species. In this review, we aim to define the ebolavirus species-specific virulence on the basis of currently available laboratory and experimental findings. In addition, this review will also cover the variant-specific virulence of EBOV by referring to the unique biological and pathogenic characteristics of EBOV variant Makona, a new EBOV variant isolated from the 2013-2016 EBOV disease outbreak in West Africa. A better definition of species-specific and variant-specific virulence of ebolaviruses will facilitate our comprehensive knowledge on genus Ebolavirus biology, leading to the development of therapeutics against well-focused pathogenic mechanisms of each Ebola disease.
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Affiliation(s)
- Satoko Yamaoka
- Department of Molecular Medicine, Mayo Clinic, Rochester, USA
| | - Hideki Ebihara
- Department of Molecular Medicine, Mayo Clinic, Rochester, USA
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10
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Downs I, Johnson JC, Rossi F, Dyer D, Saunders DL, Twenhafel NA, Esham HL, Pratt WD, Trefry J, Zumbrun E, Facemire PR, Johnston SC, Tompkins EL, Jansen NK, Honko A, Cardile AP. Natural History of Aerosol-Induced Ebola Virus Disease in Rhesus Macaques. Viruses 2021; 13:v13112297. [PMID: 34835103 PMCID: PMC8619410 DOI: 10.3390/v13112297] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 11/03/2021] [Accepted: 11/12/2021] [Indexed: 02/06/2023] Open
Abstract
Ebola virus disease (EVD) is a serious global health concern because case fatality rates are approximately 50% due to recent widespread outbreaks in Africa. Well-defined nonhuman primate (NHP) models for different routes of Ebola virus exposure are needed to test the efficacy of candidate countermeasures. In this natural history study, four rhesus macaques were challenged via aerosol with a target titer of 1000 plaque-forming units per milliliter of Ebola virus. The course of disease was split into the following stages for descriptive purposes: subclinical, clinical, and decompensated. During the subclinical stage, high levels of venous partial pressure of carbon dioxide led to respiratory acidemia in three of four of the NHPs, and all developed lymphopenia. During the clinical stage, all animals had fever, viremia, and respiratory alkalosis. The decompensatory stage involved coagulopathy, cytokine storm, and liver and renal injury. These events were followed by hypotension, elevated lactate, metabolic acidemia, shock and mortality similar to historic intramuscular challenge studies. Viral loads in the lungs of aerosol-exposed animals were not distinctly different compared to previous intramuscularly challenged studies. Differences in the aerosol model, compared to intramuscular model, include an extended subclinical stage, shortened clinical stage, and general decompensated stage. Therefore, the shortened timeframe for clinical detection of the aerosol-induced disease can impair timely therapeutic administration. In summary, this nonhuman primate model of aerosol-induced EVD characterizes early disease markers and additional details to enable countermeasure development.
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Affiliation(s)
- Isaac Downs
- US Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, MD 21702, USA; (J.C.J.); (F.R.); (D.D.); (D.L.S.); (N.A.T.); (H.L.E.); (W.D.P.); (J.T.); (E.Z.); (P.R.F.); (S.C.J.); (E.L.T.); (N.K.J.); (A.H.); (A.P.C.)
- Correspondence: ; Tel.: +1-301-619-0369
| | - Joshua C. Johnson
- US Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, MD 21702, USA; (J.C.J.); (F.R.); (D.D.); (D.L.S.); (N.A.T.); (H.L.E.); (W.D.P.); (J.T.); (E.Z.); (P.R.F.); (S.C.J.); (E.L.T.); (N.K.J.); (A.H.); (A.P.C.)
- Moderna, Inc., Cambridge, MA 02139, USA
| | - Franco Rossi
- US Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, MD 21702, USA; (J.C.J.); (F.R.); (D.D.); (D.L.S.); (N.A.T.); (H.L.E.); (W.D.P.); (J.T.); (E.Z.); (P.R.F.); (S.C.J.); (E.L.T.); (N.K.J.); (A.H.); (A.P.C.)
| | - David Dyer
- US Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, MD 21702, USA; (J.C.J.); (F.R.); (D.D.); (D.L.S.); (N.A.T.); (H.L.E.); (W.D.P.); (J.T.); (E.Z.); (P.R.F.); (S.C.J.); (E.L.T.); (N.K.J.); (A.H.); (A.P.C.)
| | - David L. Saunders
- US Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, MD 21702, USA; (J.C.J.); (F.R.); (D.D.); (D.L.S.); (N.A.T.); (H.L.E.); (W.D.P.); (J.T.); (E.Z.); (P.R.F.); (S.C.J.); (E.L.T.); (N.K.J.); (A.H.); (A.P.C.)
| | - Nancy A. Twenhafel
- US Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, MD 21702, USA; (J.C.J.); (F.R.); (D.D.); (D.L.S.); (N.A.T.); (H.L.E.); (W.D.P.); (J.T.); (E.Z.); (P.R.F.); (S.C.J.); (E.L.T.); (N.K.J.); (A.H.); (A.P.C.)
| | - Heather L. Esham
- US Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, MD 21702, USA; (J.C.J.); (F.R.); (D.D.); (D.L.S.); (N.A.T.); (H.L.E.); (W.D.P.); (J.T.); (E.Z.); (P.R.F.); (S.C.J.); (E.L.T.); (N.K.J.); (A.H.); (A.P.C.)
| | - William D. Pratt
- US Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, MD 21702, USA; (J.C.J.); (F.R.); (D.D.); (D.L.S.); (N.A.T.); (H.L.E.); (W.D.P.); (J.T.); (E.Z.); (P.R.F.); (S.C.J.); (E.L.T.); (N.K.J.); (A.H.); (A.P.C.)
| | - John Trefry
- US Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, MD 21702, USA; (J.C.J.); (F.R.); (D.D.); (D.L.S.); (N.A.T.); (H.L.E.); (W.D.P.); (J.T.); (E.Z.); (P.R.F.); (S.C.J.); (E.L.T.); (N.K.J.); (A.H.); (A.P.C.)
- Defense Threat Reduction Agency, Fort Belvoir, VA 22060, USA
| | - Elizabeth Zumbrun
- US Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, MD 21702, USA; (J.C.J.); (F.R.); (D.D.); (D.L.S.); (N.A.T.); (H.L.E.); (W.D.P.); (J.T.); (E.Z.); (P.R.F.); (S.C.J.); (E.L.T.); (N.K.J.); (A.H.); (A.P.C.)
| | - Paul R. Facemire
- US Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, MD 21702, USA; (J.C.J.); (F.R.); (D.D.); (D.L.S.); (N.A.T.); (H.L.E.); (W.D.P.); (J.T.); (E.Z.); (P.R.F.); (S.C.J.); (E.L.T.); (N.K.J.); (A.H.); (A.P.C.)
| | - Sara C. Johnston
- US Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, MD 21702, USA; (J.C.J.); (F.R.); (D.D.); (D.L.S.); (N.A.T.); (H.L.E.); (W.D.P.); (J.T.); (E.Z.); (P.R.F.); (S.C.J.); (E.L.T.); (N.K.J.); (A.H.); (A.P.C.)
| | - Erin L. Tompkins
- US Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, MD 21702, USA; (J.C.J.); (F.R.); (D.D.); (D.L.S.); (N.A.T.); (H.L.E.); (W.D.P.); (J.T.); (E.Z.); (P.R.F.); (S.C.J.); (E.L.T.); (N.K.J.); (A.H.); (A.P.C.)
| | - Nathan K. Jansen
- US Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, MD 21702, USA; (J.C.J.); (F.R.); (D.D.); (D.L.S.); (N.A.T.); (H.L.E.); (W.D.P.); (J.T.); (E.Z.); (P.R.F.); (S.C.J.); (E.L.T.); (N.K.J.); (A.H.); (A.P.C.)
| | - Anna Honko
- US Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, MD 21702, USA; (J.C.J.); (F.R.); (D.D.); (D.L.S.); (N.A.T.); (H.L.E.); (W.D.P.); (J.T.); (E.Z.); (P.R.F.); (S.C.J.); (E.L.T.); (N.K.J.); (A.H.); (A.P.C.)
- Investigator at National Emerging Infectious Diseases Laboratories, Boston University School of Medicine, Boston, MA 02118, USA
| | - Anthony P. Cardile
- US Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, Frederick, MD 21702, USA; (J.C.J.); (F.R.); (D.D.); (D.L.S.); (N.A.T.); (H.L.E.); (W.D.P.); (J.T.); (E.Z.); (P.R.F.); (S.C.J.); (E.L.T.); (N.K.J.); (A.H.); (A.P.C.)
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11
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Chukwurah E, Farabaugh KT, Guan BJ, Ramakrishnan P, Hatzoglou M. A tale of two proteins: PACT and PKR and their roles in inflammation. FEBS J 2021; 288:6365-6391. [PMID: 33387379 PMCID: PMC9248962 DOI: 10.1111/febs.15691] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 12/14/2020] [Accepted: 12/29/2020] [Indexed: 12/12/2022]
Abstract
Inflammation is a pathological hallmark associated with bacterial and viral infections, autoimmune diseases, genetic disorders, obesity and diabetes, as well as environmental stresses including physical and chemical trauma. Among numerous proteins regulating proinflammatory signaling, very few such as Protein kinase R (PKR), have been shown to play an all-pervading role in inflammation induced by varied stimuli. PKR was initially characterized as an interferon-inducible gene activated by viral double-stranded RNA with a role in protein translation inhibition. However, it has become increasingly clear that PKR is involved in multiple pathways that promote inflammation in response to stress activation, both dependent on and independent of its cellular protein activator of PKR (PACT). In this review, we discuss the signaling pathways that contribute to the initiation of inflammation, including Toll-like receptor, interferon, and RIG-I-like receptor signaling, as well as inflammasome activation. We go on to discuss the specific roles that PKR and PACT play in such proinflammatory signaling, as well as in metabolic syndrome- and environmental stress-induced inflammation.
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Affiliation(s)
- Evelyn Chukwurah
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH 44106
| | - Kenneth T. Farabaugh
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH 44106
| | - Bo-Jhih Guan
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH 44106
| | | | - Maria Hatzoglou
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH 44106
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12
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[The latest research findings on Ebola virus]. Uirusu 2021; 71:137-150. [PMID: 37245976 DOI: 10.2222/jsv.71.137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
013-2016 Ebola virus disease (EVD) outbreak was the largest EVD outbreak ever documented that started earlier in Guinea and later widely spread throughout West Africa, ending up a total of > 28,000 human infections. In this review, we outline research findings on Ebola virus (EBOV) variant Makona, a new EBOV variant isolated from the 2013-2016 EVD outbreak, and introduce the unique biological and pathogenic characteristics of Makona variant. We also discuss about the relevance of persistent infection of EBOV in EVD survivors with resurgence of EVD outbreak in Guinea in 2021. Moreover, this review covers a recent case report of EVD relapse and deliberates new interpretations of EBOV biology and EVD outbreak.
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13
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Banerjee A, Mitra P. Ebola Virus VP35 Protein: Modeling of the Tetrameric Structure and an Analysis of Its Interaction with Human PKR. J Proteome Res 2020; 19:4533-4542. [PMID: 32871072 PMCID: PMC7640970 DOI: 10.1021/acs.jproteome.0c00473] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Indexed: 01/12/2023]
Abstract
The Viral Protein 35 (VP35), a crucial protein of the Zaire Ebolavirus (EBOV), interacts with a plethora of human proteins to cripple the human immune system. Despite its importance, the entire structure of the tetrameric assembly of EBOV VP35 and the means by which it antagonizes the autophosphorylation of the kinase domain of human protein kinase R (PKRK) is still elusive. We consult existing structural information to model a tetrameric assembly of the VP35 protein where 93% of the protein is modeled using crystal structure templates. We analyze our modeled tetrameric structure to identify interchain bonding networks and use molecular dynamics simulations and normal-mode analysis to unravel the flexibility and deformability of the different regions of the VP35 protein. We establish that the C-terminal of VP35 (VP35C) directly interacts with PKRK to prevent it from autophosphorylation. Further, we identify three plausible VP35C-PKRK complexes with better affinity than the PKRK dimer formed during autophosphorylation and use protein design to establish a new stretch in VP35C that interacts with PKRK. The proposed tetrameric assembly will aid in better understanding of the VP35 protein, and the reported VP35C-PKRK complexes along with their interacting sites will help in the shortlisting of small molecule inhibitors.
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Affiliation(s)
- Anupam Banerjee
- Advanced
Technology Development Centre, Indian Institute of Technology Kharagpur, West Bengal 721302, India
| | - Pralay Mitra
- Department
of Computer Science and Engineering, Indian
Institute of Technology Kharagpur, West Bengal 721302, India
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14
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Dutta S, Das N, Mukherjee P. Picking up a Fight: Fine Tuning Mitochondrial Innate Immune Defenses Against RNA Viruses. Front Microbiol 2020; 11:1990. [PMID: 32983015 PMCID: PMC7487669 DOI: 10.3389/fmicb.2020.01990] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 07/28/2020] [Indexed: 12/20/2022] Open
Abstract
As the world faces the challenge of the COVID-19 pandemic, it has become an urgent need of the hour to understand how our immune system sense and respond to RNA viruses that are often life-threatening. While most vaccine strategies for these viruses are developed around a programmed antibody response, relatively less attention is paid to our innate immune defenses that can determine the outcome of a viral infection via the production of antiviral cytokines like Type I Interferons. However, it is becoming increasingly evident that the "cytokine storm" induced by aberrant activation of the innate immune response against a viral pathogen may sometimes offer replicative advantage to the virus thus promoting disease pathogenesis. Thus, it is important to fine tune the responses of the innate immune network that can be achieved via a deeper insight into the candidate molecules involved. Several pattern recognition receptors (PRRs) like the Toll like receptors (TLRs), NOD-like receptors (NLRs), and the retinoic acid inducible gene-I (RIG-I) like receptors (RLRs) recognize cytosolic RNA viruses and mount an antiviral immune response. RLRs recognize invasive viral RNA produced during infection and mediate the induction of Type I Interferons via the mitochondrial antiviral signaling (MAVS) molecule. It is an intriguing fact that the mitochondrion, one of the cell's most vital organelle, has evolved to be a central hub in this antiviral defense. However, cytokine responses and interferon signaling via MAVS signalosome at the mitochondria must be tightly regulated to prevent overactivation of the immune responses. This review focuses on our current understanding of the innate immune sensing of the host mitochondria by the RLR-MAVS signalosome and its specificity against some of the emerging/re-emerging RNA viruses like Ebola, Zika, Influenza A virus (IAV), and severe acute respiratory syndrome-coronavirus (SARS-CoV) that may expand our understanding for novel pharmaceutical development.
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15
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Impact of Měnglà Virus Proteins on Human and Bat Innate Immune Pathways. J Virol 2020; 94:JVI.00191-20. [PMID: 32295912 DOI: 10.1128/jvi.00191-20] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 04/07/2020] [Indexed: 12/31/2022] Open
Abstract
Měnglà virus (MLAV), identified in Rousettus bats, is a phylogenetically distinct member of the family Filoviridae Because the filoviruses Ebola virus (EBOV) and Marburg virus (MARV) modulate host innate immunity, MLAV VP35, VP40, and VP24 proteins were compared with their EBOV and MARV homologs for innate immune pathway modulation. In human and Rousettus cells, MLAV VP35 behaved like EBOV and MARV VP35s, inhibiting virus-induced activation of the interferon beta (IFN-β) promoter and interferon regulatory factor 3 (IRF3) phosphorylation. MLAV VP35 also interacted with PACT, a host protein engaged by EBOV VP35 to inhibit RIG-I signaling. MLAV VP35 also inhibits PKR activation. MLAV VP40 was demonstrated to inhibit type I IFN-induced gene expression in human and bat cells. It blocked STAT1 tyrosine phosphorylation induced either by type I IFN or overexpressed Jak1, paralleling MARV VP40. MLAV VP40 also inhibited virus-induced IFN-β promoter activation, a property shared by MARV VP40 and EBOV VP24. A Jak kinase inhibitor did not recapitulate this inhibition in the absence of viral proteins. Therefore, inhibition of Jak-STAT signaling is insufficient to explain inhibition of IFN-β promoter activation. MLAV VP24 did not inhibit IFN-induced gene expression or bind karyopherin α proteins, properties of EBOV VP24. MLAV VP24 differed from MARV VP24 in that it failed to interact with Keap1 or activate an antioxidant response element reporter gene due to the absence of a Keap1-binding motif. These functional observations support a closer relationship of MLAV to MARV than to EBOV but also are consistent with MLAV belonging to a distinct genus.IMPORTANCE EBOV and MARV, members of the family Filoviridae, are highly pathogenic zoonotic viruses that cause severe disease in humans. Both viruses use several mechanisms to modulate the host innate immune response, and these likely contribute to the severity of disease. Here, we demonstrate that MLAV, a filovirus newly discovered in a bat, suppresses antiviral type I interferon responses in both human and bat cells. Inhibitory activities are possessed by MLAV VP35 and VP40, which parallels how MARV blocks IFN responses. However, whereas MARV activates cellular antioxidant responses through an interaction between its VP24 protein and host protein Keap1, MLAV VP24 lacks a Keap1-binding motif and fails to activate this cytoprotective response. These data indicate that MLAV possesses immune-suppressing functions that could facilitate human infection. They also support the placement of MLAV in a different genus than either EBOV or MARV.
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16
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Fanunza E, Frau A, Corona A, Tramontano E. Insights into Ebola Virus VP35 and VP24 Interferon Inhibitory Functions and their Initial Exploitation as Drug Targets. Infect Disord Drug Targets 2020; 19:362-374. [PMID: 30468131 DOI: 10.2174/1871526519666181123145540] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 11/14/2018] [Accepted: 11/16/2018] [Indexed: 12/15/2022]
Abstract
Upon viral infection, the interferon (IFN) system triggers potent antiviral mechanisms limiting viral growth and spread. Hence, to sustain their infection, viruses evolved efficient counteracting strategies to evade IFN control. Ebola virus (EBOV), member of the family Filoviridae, is one of the most virulent and deadly pathogen ever faced by humans. The etiological agent of the Ebola Virus Disease (EVD), EBOV can be undoubtedly considered the perfect example of a powerful inhibitor of the host organism immune response activation. Particularly, the efficacious suppression of the IFN cascade contributes to disease progression and severity. Among the EBOVencoded proteins, the Viral Proteins 35 (VP35) and 24 (VP24) are responsible for the EBOV extreme virulence, representing the core of such inhibitory function through which EBOV determines its very effective shield to the cellular immune defenses. VP35 inhibits the activation of the cascade leading to IFN production, while VP24 inhibits the activation of the IFN-stimulated genes. A number of studies demonstrated that both VP35 and VP24 is validated target for drug development. Insights into the structural characteristics of VP35 and VP24 domains revealed crucial pockets exploitable for drug development. Considered the lack of therapy for EVD, restoring the immune activation is a promising approach for drug development. In the present review, we summarize the importance of VP35 and VP24 proteins in counteracting the host IFN cellular response and discuss their potential as druggable viral targets as a promising approach toward attenuation of EBOV virulence.
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Affiliation(s)
- Elisa Fanunza
- Department of Life and Environmental Sciences, University of Cagliari, Sardinia, Italy
| | - Aldo Frau
- Department of Life and Environmental Sciences, University of Cagliari, Sardinia, Italy
| | - Angela Corona
- Department of Life and Environmental Sciences, University of Cagliari, Sardinia, Italy
| | - Enzo Tramontano
- Department of Life and Environmental Sciences, University of Cagliari, Sardinia, Italy.,Genetics and Biomedical Research Institute, National Research Council, Monserrato, Italy
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17
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Jacob ST, Crozier I, Fischer WA, Hewlett A, Kraft CS, Vega MADL, Soka MJ, Wahl V, Griffiths A, Bollinger L, Kuhn JH. Ebola virus disease. Nat Rev Dis Primers 2020; 6:13. [PMID: 32080199 PMCID: PMC7223853 DOI: 10.1038/s41572-020-0147-3] [Citation(s) in RCA: 278] [Impact Index Per Article: 69.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/10/2020] [Indexed: 12/16/2022]
Abstract
Ebola virus disease (EVD) is a severe and frequently lethal disease caused by Ebola virus (EBOV). EVD outbreaks typically start from a single case of probable zoonotic transmission, followed by human-to-human transmission via direct contact or contact with infected bodily fluids or contaminated fomites. EVD has a high case-fatality rate; it is characterized by fever, gastrointestinal signs and multiple organ dysfunction syndrome. Diagnosis requires a combination of case definition and laboratory tests, typically real-time reverse transcription PCR to detect viral RNA or rapid diagnostic tests based on immunoassays to detect EBOV antigens. Recent advances in medical countermeasure research resulted in the recent approval of an EBOV-targeted vaccine by European and US regulatory agencies. The results of a randomized clinical trial of investigational therapeutics for EVD demonstrated survival benefits from two monoclonal antibody products targeting the EBOV membrane glycoprotein. New observations emerging from the unprecedented 2013-2016 Western African EVD outbreak (the largest in history) and the ongoing EVD outbreak in the Democratic Republic of the Congo have substantially improved the understanding of EVD and viral persistence in survivors of EVD, resulting in new strategies toward prevention of infection and optimization of clinical management, acute illness outcomes and attendance to the clinical care needs of patients.
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Affiliation(s)
- Shevin T Jacob
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
- Global Health Security Department, Infectious Diseases Institute, Makerere University, Kampala, Uganda
| | - Ian Crozier
- Integrated Research Facility at Fort Detrick, Clinical Monitoring Research Program Directorate, Frederick National Laboratory for Cancer Research supported by the National Cancer Institute, Frederick, MD, USA
| | - William A Fischer
- Department of Medicine, Division of Pulmonary Disease and Critical Care Medicine, Chapel Hill, NC, USA
| | - Angela Hewlett
- Nebraska Biocontainment Unit, Division of Infectious Diseases, University of Nebraska Medical Center, Omaha, NE, USA
| | - Colleen S Kraft
- Microbiology Section, Emory Medical Laboratory, Emory University School of Medicine, Atlanta, GA, USA
| | - Marc-Antoine de La Vega
- Department of Microbiology, Immunology & Infectious Diseases, Université Laval, Quebec City, QC, Canada
| | - Moses J Soka
- Partnership for Ebola Virus Disease Research in Liberia, Monrovia Medical Units ELWA-2 Hospital, Monrovia, Liberia
| | - Victoria Wahl
- National Biodefense Analysis and Countermeasures Center, Fort Detrick, Frederick, MD, USA
| | - Anthony Griffiths
- Department of Microbiology and National Emerging Infectious Diseases Laboratories, Boston University School of Medicine, Boston, MA, USA
| | - Laura Bollinger
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, MD, USA
| | - Jens H Kuhn
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, MD, USA.
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18
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Clarke EC, Bradfute SB. The use of mice lacking type I or both type I and type II interferon responses in research on hemorrhagic fever viruses. Part 1: Potential effects on adaptive immunity and response to vaccination. Antiviral Res 2020; 174:104703. [DOI: 10.1016/j.antiviral.2019.104703] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 12/10/2019] [Accepted: 12/20/2019] [Indexed: 12/25/2022]
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19
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Conservation of Structure and Immune Antagonist Functions of Filoviral VP35 Homologs Present in Microbat Genomes. Cell Rep 2020; 24:861-872.e6. [PMID: 30044983 DOI: 10.1016/j.celrep.2018.06.045] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 04/29/2018] [Accepted: 06/11/2018] [Indexed: 11/20/2022] Open
Abstract
Non-retroviral integrated RNA viral sequences (NIRVs) potentially encoding ∼280 amino acid homologs to filovirus VP35 proteins are present across the Myotis genus of bats. These are estimated to have been maintained for ∼18 million years, indicating their co-option. To address the reasons for co-option, 16 Myotis VP35s were characterized in comparison to VP35s from the extant filoviruses Ebola virus and Marburg virus, in which VP35s play critical roles in immune evasion and RNA synthesis. The Myotis VP35s demonstrated a conserved suppression of innate immune signaling, albeit with reduced potency, in either human or Myotis cells. Their attenuation reflects a lack of dsRNA binding that in the filoviral VP35s correlates with potent suppression of interferon responses. Despite divergent function, evolution has preserved in Myotis the structure of the filoviral VP35s, indicating that this structure is critical for co-opted function, possibly as a regulator of innate immune signaling.
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20
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[Molecular mechanisms of highly pathogenic viruses' replication and their applications for a novel drug discovery]. Uirusu 2020; 70:69-82. [PMID: 33967116 DOI: 10.2222/jsv.70.69] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Productive (lytic) replication of DNA viruses elicits host cell DNA damage responses, which cause both beneficial and detrimental effects on viral replication. Viruses utilize them and selectively cancel the 'noisy' downstream signaling pathways, leading to maintain high S-phase CDK activities required for viral replication. To achieve this fine tuning of cellular environment, herpesviruses encode many (>70) genes in their genome, which are expressed in a strictly regulated temporal cascade (immediate-early, early, and late). Here, I introduce and discuss how Epstein-Barr virus, an oncogenic herpesvirus, hijacks the cellular environment and adapt it for the progeny production.
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21
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Ebola virus replication is regulated by the phosphorylation of viral protein VP35. Biochem Biophys Res Commun 2019; 521:687-692. [PMID: 31694758 DOI: 10.1016/j.bbrc.2019.10.147] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Accepted: 10/22/2019] [Indexed: 02/04/2023]
Abstract
Ebola virus (EBOV) is a zoonotic pathogen, the infection often results in severe, potentially fatal, systematic disease in human and nonhuman primates. VP35, an essential viral RNA-dependent RNA polymerase cofactor, is indispensable for Ebola viral replication and host innate immune escape. In this study, VP35 was demonstrated to be phosphorylated at Serine/Threonine by immunoblotting, and the major phosphorylation sites was S187, S205, T206, S208 and S317 as revealed by LC-MS/MS. By an EBOV minigenomic system, EBOV minigenome replication was shown to be significantly inhibited by the phosphorylation-defective mutant, VP35 S187A, but was potentiated by the phosphorylation mimic mutant VP35 S187D. Together, our findings demonstrate that EBOV VP35 is phosphorylated on multiple residues in host cells, especially on S187, which may contribute to efficient viral genomic replication and viral proliferation.
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22
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Hume A, Mühlberger E. Marburg Virus Viral Protein 35 Inhibits Protein Kinase R Activation in a Cell Type-Specific Manner. J Infect Dis 2019; 218:S403-S408. [PMID: 30165526 DOI: 10.1093/infdis/jiy473] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Protein kinase R (PKR) is a key antiviral protein involved in sensing and restricting viral infections. Here we analyzed the ability of Marburg virus (MARV) viral protein 35 (VP35) to inhibit PKR activation in human and bat cells. Similar to the related Ebola and Lloviu viruses, MARV VP35 was able to inhibit PKR activation in 293T cells. In contrast, we found that MARV VP35 did not inhibit human or bat PKR activation in human glioblastoma U-251-MG cells or a Rousettus aegyptiacus cell line. Additional experiments revealed that PACT, a known PKR regulator, was insufficient to rescue the ability of VP35 to inhibit PKR activation in these cells. Taken together, this study indicates that the ability of VP35 to inhibit PKR is cell type specific, potentially explaining discrepancies between the ability of filoviruses to potently block innate immune responses, and the high levels of interferon and interferon-stimulated genes observed in filovirus patients.
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Affiliation(s)
- Adam Hume
- Department of Microbiology, Boston University School of Medicine
- National Emerging Infectious Diseases Laboratories, Boston University, Massachusetts
| | - Elke Mühlberger
- Department of Microbiology, Boston University School of Medicine
- National Emerging Infectious Diseases Laboratories, Boston University, Massachusetts
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23
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Jasenosky LD, Cadena C, Mire CE, Borisevich V, Haridas V, Ranjbar S, Nambu A, Bavari S, Soloveva V, Sadukhan S, Cassell GH, Geisbert TW, Hur S, Goldfeld AE. The FDA-Approved Oral Drug Nitazoxanide Amplifies Host Antiviral Responses and Inhibits Ebola Virus. iScience 2019; 19:1279-1290. [PMID: 31402258 PMCID: PMC6831822 DOI: 10.1016/j.isci.2019.07.003] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 06/03/2019] [Accepted: 06/28/2019] [Indexed: 12/24/2022] Open
Abstract
Here, we show that the US Food and Drug Administration-approved oral drug nitazoxanide (NTZ) broadly amplifies the host innate immune response to viruses and inhibits Ebola virus (EBOV) replication. We find that NTZ enhances retinoic-acid-inducible protein I (RIG-I)-like-receptor, mitochondrial antiviral signaling protein, interferon regulatory factor 3, and interferon activities and induces transcription of the antiviral phosphatase GADD34. NTZ significantly inhibits EBOV replication in human cells through its effects on RIG-I and protein kinase R (PKR), suggesting that it counteracts EBOV VP35 protein's ability to block RIG-I and PKR sensing of EBOV. NTZ also inhibits a second negative-strand RNA virus, vesicular stomatitis virus (VSV), through RIG-I and GADD34, but not PKR, consistent with VSV's distinct host innate immune evasion mechanisms. Thus, NTZ counteracts varied virus-specific immune evasion strategies by generally enhancing the RNA sensing and interferon axis that is triggered by foreign cytoplasmic RNA exposure, and holds promise as an oral therapy against EBOV. NTZ amplifies RNA sensor and type I interferon activities and induces GADD34 expression NTZ inhibits infectious Ebola virus (EBOV) via RIG-I and PKR, but not GADD34 NTZ inhibits a second negative-strand RNA virus, VSV, via RIG-I and GADD34, but not PKR NTZ holds promise as an oral therapy against EBOV
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Affiliation(s)
- Luke D Jasenosky
- Program in Cellular and Molecular Medicine, Children's Hospital Boston, Harvard Medical School, Boston, MA 02115, USA
| | - Cristhian Cadena
- Program in Cellular and Molecular Medicine, Children's Hospital Boston, Harvard Medical School, Boston, MA 02115, USA
| | - Chad E Mire
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Viktoriya Borisevich
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Viraga Haridas
- Program in Cellular and Molecular Medicine, Children's Hospital Boston, Harvard Medical School, Boston, MA 02115, USA
| | - Shahin Ranjbar
- Program in Cellular and Molecular Medicine, Children's Hospital Boston, Harvard Medical School, Boston, MA 02115, USA
| | - Aya Nambu
- Program in Cellular and Molecular Medicine, Children's Hospital Boston, Harvard Medical School, Boston, MA 02115, USA
| | - Sina Bavari
- U.S. Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD 21702, USA
| | - Veronica Soloveva
- U.S. Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD 21702, USA
| | - Supriya Sadukhan
- Program in Cellular and Molecular Medicine, Children's Hospital Boston, Harvard Medical School, Boston, MA 02115, USA
| | - Gail H Cassell
- Department of Global Health and Social Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Thomas W Geisbert
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Sun Hur
- Program in Cellular and Molecular Medicine, Children's Hospital Boston, Harvard Medical School, Boston, MA 02115, USA
| | - Anne E Goldfeld
- Program in Cellular and Molecular Medicine, Children's Hospital Boston, Harvard Medical School, Boston, MA 02115, USA; Infectious Disease Division, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA; Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
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Abstract
The filoviruses are etiological agents of life-threatening hemorrhagic fever with high mortality rate and risk of potential outbreak. Among members of this family, the Ebola (EBOV), Sudan (SUDV), and Marburg (MARV) viruses are considered the most pathogenic for humans. The ebolavirus nucleoprotein (NP) is the most abundant protein in infected cells and is essential for viral transcription and replication; thus, it represents an attractive target for therapeutic intervention. Here, we present the structure of SUDV NP in complex with the amino-terminal portion of the phosphoprotein VP35 at 2.3 Å. This structure captures VP35 chaperoning SUDV NP in a monomeric and RNA-free state. This transient state has been proposed to be key to maintaining a pool of monomeric and RNA-free NPs prior to NP-NP polymerization and encapsidation of the viral RNA genome. This structure also reveals a newly visualized interaction between NP and VP35, a well-defined beta sheet that is not present in previous structures. Affinity binding assays demonstrate that this beta sheet is essential for maintaining the high-affinity interaction between VP35 and a hydrophobic pocket on SUDV NP, and electron microscopy indicates the importance of this binding interaction to the oligomeric state and assembly of NP in human cells. Complementary structure-directed mutagenesis identifies critical residues conserved across the filovirus family that could be targeted by broadly effective antivirals.IMPORTANCE Outbreaks of the filoviruses can be unpredictable in timing, location, and identity of the causative virus, with each of Ebola virus, Sudan virus, Bundibugyo virus, and Marburg virus reemerging in the last several years to cause human disease with 30 to 90% lethality. The 2014-2016 outbreak in particular, with nearly 30,000 patients, highlighted the ability of these viruses to emerge unexpectedly and spread rapidly. Two ebolavirus outbreaks have emerged this year, yet we still lack FDA-approved drugs with pan-filovirus activity to treat existing and emergent ebolaviruses. For all filoviruses, the interaction between the nucleoprotein and the phosphoprotein is essential for the virus life cycle and is a potential target for therapeutic intervention. In this report, we describe the crystal structure of the SUDV nucleoprotein with the interacting domain of the viral phosphoprotein, and we identify residues critical for high-affinity interaction and for control of the oligomeric state of the nucleoprotein. Structural comparison of this heterodimer with other members of the filovirus family allowed us to find conserved and essential atomic features that will facilitate understanding of the virus life cycle and the rational design of antivirals.
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Olejnik J, Hume AJ, Leung DW, Amarasinghe GK, Basler CF, Mühlberger E. Filovirus Strategies to Escape Antiviral Responses. Curr Top Microbiol Immunol 2019; 411:293-322. [PMID: 28685291 PMCID: PMC5973841 DOI: 10.1007/82_2017_13] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This chapter describes the various strategies filoviruses use to escape host immune responses with a focus on innate immune and cell death pathways. Since filovirus replication can be efficiently blocked by interferon (IFN), filoviruses have evolved mechanisms to counteract both type I IFN induction and IFN response signaling pathways. Intriguingly, marburg- and ebolaviruses use different strategies to inhibit IFN signaling. This chapter also summarizes what is known about the role of IFN-stimulated genes (ISGs) in filovirus infection. These fall into three categories: those that restrict filovirus replication, those whose activation is inhibited by filoviruses, and those that have no measurable effect on viral replication. In addition to innate immunity, mammalian cells have evolved strategies to counter viral infections, including the induction of cell death and stress response pathways, and we summarize our current knowledge of how filoviruses interact with these pathways. Finally, this chapter delves into the interaction of EBOV with myeloid dendritic cells and macrophages and the associated inflammatory response, which differs dramatically between these cell types when they are infected with EBOV. In summary, we highlight the multifaceted nature of the host-viral interactions during filoviral infections.
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Affiliation(s)
- Judith Olejnik
- Department of Microbiology and National Emerging Infectious Diseases Laboratories, Boston University School of Medicine, 620 Albany Street, Boston, MA, 02118, USA
| | - Adam J Hume
- Department of Microbiology and National Emerging Infectious Diseases Laboratories, Boston University School of Medicine, 620 Albany Street, Boston, MA, 02118, USA
| | - Daisy W Leung
- Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA
| | - Gaya K Amarasinghe
- Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, St. Louis, MO, 63110, USA
| | - Christopher F Basler
- Microbial Pathogenesis, Georgia State University, Institute for Biomedical Sciences, Atlanta, GA, 30303, USA
| | - Elke Mühlberger
- Department of Microbiology and National Emerging Infectious Diseases Laboratories, Boston University School of Medicine, 620 Albany Street, Boston, MA, 02118, USA.
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Essential Role of Enterovirus 2A Protease in Counteracting Stress Granule Formation and the Induction of Type I Interferon. J Virol 2019; 93:JVI.00222-19. [PMID: 30867299 DOI: 10.1128/jvi.00222-19] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 03/04/2019] [Indexed: 12/20/2022] Open
Abstract
Most viruses have acquired mechanisms to suppress antiviral alpha/beta interferon (IFN-α/β) and stress responses. Enteroviruses (EVs) actively counteract the induction of IFN-α/β gene transcription and stress granule (SG) formation, which are increasingly implicated as a platform for antiviral signaling, but the underlying mechanisms remain poorly understood. Both viral proteases (2Apro and 3Cpro) have been implicated in the suppression of these responses, but these conclusions predominantly rely on ectopic overexpression of viral proteases or addition of purified viral proteases to cell lysates. Here, we present a detailed and comprehensive comparison of the effect of individual enterovirus proteases on the formation of SGs and the induction of IFN-α/β gene expression in infected cells for representative members of the enterovirus species EV-A to EV-D. First, we show that SG formation and IFN-β induction are suppressed in cells infected with EV-A71, coxsackie B3 virus (CV-B3), CV-A21, and EV-D68. By introducing genes encoding CV-B3 proteases in a recombinant encephalomyocarditis virus (EMCV) that was designed to efficiently activate antiviral responses, we show that CV-B3 2Apro, but not 3Cpro, is the major antagonist that counters SG formation and IFN-β gene transcription and that 2Apro's proteolytic activity is essential for both functions. 2Apro efficiently suppressed SG formation despite protein kinase R (PKR) activation and α subunit of eukaryotic translation initiation factor 2 phosphorylation, suggesting that 2Apro antagonizes SG assembly or promotes its disassembly. Finally, we show that the ability to suppress SG formation and IFN-β gene transcription is conserved in the 2Apro of EV-A71, CV-A21, and EV-D68. Collectively, our results indicate that enterovirus 2Apro plays a key role in inhibiting innate antiviral cellular responses.IMPORTANCE Enteroviruses are important pathogens that can cause a variety of diseases in humans, including aseptic meningitis, myocarditis, hand-foot-and-mouth disease, conjunctivitis, and acute flaccid paralysis. Like many other viruses, enteroviruses must counteract antiviral cellular responses to establish an infection. It has been suggested that enterovirus proteases cleave cellular factors to perturb antiviral pathways, but the exact contribution of viral proteases 2Apro and 3Cpro remains elusive. Here, we show that 2Apro, but not 3Cpro, of all four human EV species (EV-A to EV-D) inhibits SG formation and IFN-β gene transcription. Our observations suggest that enterovirus 2Apro has a conserved function in counteracting antiviral host responses and thereby is the main enterovirus "security protein." Understanding the molecular mechanisms of enterovirus immune evasion strategies may help to develop countermeasures to control infections with these viruses.
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Role of Type I Interferons on Filovirus Pathogenesis. Vaccines (Basel) 2019; 7:vaccines7010022. [PMID: 30791589 PMCID: PMC6466283 DOI: 10.3390/vaccines7010022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 02/06/2019] [Accepted: 02/15/2019] [Indexed: 01/19/2023] Open
Abstract
Filoviruses, such as Ebola and Marburg virus, encode viral proteins with the ability to counteract the type I interferon (IFN-I) response. These IFN-I antagonist proteins are crucial to ensure virus replication, prevent an antiviral state in infected and bystander cells, and impair the ability of antigen-presenting cells to initiate adaptive immune responses. However, in recent years, a number of studies have underscored the conflicting data between in vitro studies and in vivo data obtained in animal models and clinical studies during outbreaks. This review aims to summarize these data and to discuss the relative contributions of IFN-α and IFN-β to filovirus pathogenesis in animal models and humans. Finally, we evaluate the putative utilization of IFN-I in post-exposure therapy and its implications as a biomarker of vaccine efficacy.
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28
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Di Palma F, Daino GL, Ramaswamy VK, Corona A, Frau A, Fanunza E, Vargiu AV, Tramontano E, Ruggerone P. Relevance of Ebola virus VP35 homo-dimerization on the type I interferon cascade inhibition. Antivir Chem Chemother 2019; 27:2040206619889220. [PMID: 31744306 PMCID: PMC6883671 DOI: 10.1177/2040206619889220] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 08/13/2019] [Indexed: 01/10/2023] Open
Abstract
Ebola virus high lethality relies on its ability to efficiently bypass the host innate antiviral response, which senses the viral dsRNA through the RIG-I receptor and induces type I interferon α/β production. In the bypassing action, the Ebola virus protein VP35 plays a pivotal role at multiple levels of the RIG-I cascade, masking the viral 5′-triphosphorylated dsRNA from RIG-I, and interacting with other cascade components. The VP35 type I interferon inhibition is exerted by the C-terminal domain, while the N-terminal domain, containing a coiled-coil region, is primarily required for oligomerization. However, mutations at key VP35 residues L90/93/107A (VP35-3m) in the coiled-coil region were reported to affect oligomerization and reduce type I interferon antagonism, indicating a possible but unclear role of homo-oligomerization on VP35 interaction with the RIG-I pathway components. In this work, we investigated the VP35 dimerization thermodynamics and its contribution to type I interferon antagonism by computational and biological methods. Focusing on the coiled-coil region, we combined coarse-grained and all-atom simulations on wild type VP35 and VP35-3m homo-dimerization. According to our results, wild type VP35 coiled-coil is able to self-assemble into dimers, while VP35-3m coiled-coil shows poor propensity to even dimerize. Free-energy calculations confirmed the key role of L90, L93 and L107 in stabilizing the coiled-coil homo-dimeric structure. In vitro type I interferon antagonism studies, using full-length wild type VP35 and VP35-3m, revealed that VP35 homo-dimerization is an essential preliminary step for dsRNA binding, which appears to be the main factor of the VP35 RIG-I cascade inhibition, while it is not essential to block the other steps.
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Affiliation(s)
- Francesco Di Palma
- Department of Physics, University of Cagliari, Cittadella
Universitaria, Monserrato, Italy
| | - Gian Luca Daino
- Department of Life and Environmental Sciences, University of
Cagliari, Cittadella Universitaria, Monserrato, Italy
| | | | - Angela Corona
- Department of Life and Environmental Sciences, University of
Cagliari, Cittadella Universitaria, Monserrato, Italy
| | - Aldo Frau
- Department of Life and Environmental Sciences, University of
Cagliari, Cittadella Universitaria, Monserrato, Italy
| | - Elisa Fanunza
- Department of Life and Environmental Sciences, University of
Cagliari, Cittadella Universitaria, Monserrato, Italy
| | - Attilio V Vargiu
- Department of Physics, University of Cagliari, Cittadella
Universitaria, Monserrato, Italy
| | - Enzo Tramontano
- Department of Life and Environmental Sciences, University of
Cagliari, Cittadella Universitaria, Monserrato, Italy
- Istituto di Ricerca Genetica e Biomedica, Consiglio Nazionale
delle Ricerche (CNR), Monserrato, Italy
| | - Paolo Ruggerone
- Department of Physics, University of Cagliari, Cittadella
Universitaria, Monserrato, Italy
- Istituto Officina dei Materiali (CNR-IOM), UOS Cagliari SLACS,
Monserrato, Italy
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29
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Daino GL, Frau A, Sanna C, Rigano D, Distinto S, Madau V, Esposito F, Fanunza E, Bianco G, Taglialatela-Scafati O, Zinzula L, Maccioni E, Corona A, Tramontano E. Identification of Myricetin as an Ebola Virus VP35-Double-Stranded RNA Interaction Inhibitor through a Novel Fluorescence-Based Assay. Biochemistry 2018; 57:6367-6378. [PMID: 30298725 DOI: 10.1021/acs.biochem.8b00892] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ebola virus (EBOV) is a filovirus that causes a severe and rapidly progressing hemorrhagic syndrome; a recent epidemic illustrated the urgent need for novel therapeutic agents because no drugs have been approved for treatment of Ebola virus. A key contribution to the high lethality observed during EBOV outbreaks comes from viral evasion of the host antiviral innate immune response in which viral protein VP35 plays a crucial role, blocking interferon type I production, first by masking the viral double-stranded RNA (dsRNA) and preventing its detection by the pattern recognition receptor RIG-I. Aiming to identify inhibitors of the interaction of VP35 with the viral dsRNA, counteracting the VP35 viral innate immune evasion, we established a new methodology for high-yield recombinant VP35 (rVP35) expression and purification and a novel and robust fluorescence-based rVP35-RNA interaction assay ( Z' factor of 0.69). Taking advantage of such newly established methods, we screened a small library of Sardinian natural extracts, identifying Limonium morisianum as the most potent inhibitor extract. A bioguided fractionation led to the identification of myricetin as the component that can inhibit rVP35-dsRNA interaction with an IC50 value of 2.7 μM. Molecular docking studies showed that myricetin interacts with the highly conserved region of the VP35 RNA binding domain, laying the basis for further structural optimization of potent inhibitors of VP35-dsRNA interaction.
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Affiliation(s)
- Gian Luca Daino
- Department of Life and Environmental Sciences , University of Cagliari , Cagliari 09042 , Italy
| | - Aldo Frau
- Department of Life and Environmental Sciences , University of Cagliari , Cagliari 09042 , Italy
| | - Cinzia Sanna
- Department of Life and Environmental Sciences , University of Cagliari , Cagliari 09042 , Italy
| | - Daniela Rigano
- Department of Pharmacy, School of Medicine and Surgery , University of Naples Federico II , Naples 80131 , Italy
| | - Simona Distinto
- Department of Life and Environmental Sciences , University of Cagliari , Cagliari 09042 , Italy
| | - Veronica Madau
- Department of Life and Environmental Sciences , University of Cagliari , Cagliari 09042 , Italy
| | - Francesca Esposito
- Department of Life and Environmental Sciences , University of Cagliari , Cagliari 09042 , Italy
| | - Elisa Fanunza
- Department of Life and Environmental Sciences , University of Cagliari , Cagliari 09042 , Italy
| | - Giulia Bianco
- Department of Life and Environmental Sciences , University of Cagliari , Cagliari 09042 , Italy
| | - Orazio Taglialatela-Scafati
- Department of Pharmacy, School of Medicine and Surgery , University of Naples Federico II , Naples 80131 , Italy
| | - Luca Zinzula
- The Max-Planck Institute of Biochemistry , Department of Molecular Structural Biology , Martinsried 82152 , Germany
| | - Elias Maccioni
- Department of Life and Environmental Sciences , University of Cagliari , Cagliari 09042 , Italy
| | - Angela Corona
- Department of Life and Environmental Sciences , University of Cagliari , Cagliari 09042 , Italy
| | - Enzo Tramontano
- Department of Life and Environmental Sciences , University of Cagliari , Cagliari 09042 , Italy.,Istituto di Ricerca Genetica e Biomedica , Consiglio Nazionale delle Ricerche (CNR) , Monserrato 09042 , Italy
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30
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Staufen1 Interacts with Multiple Components of the Ebola Virus Ribonucleoprotein and Enhances Viral RNA Synthesis. mBio 2018; 9:mBio.01771-18. [PMID: 30301857 PMCID: PMC6178623 DOI: 10.1128/mbio.01771-18] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Ebola virus (EBOV) is a negative-strand RNA virus with significant public health importance. Currently, no therapeutics are available for Ebola, which imposes an urgent need for a better understanding of EBOV biology. Here we dissected the virus-host interplay between EBOV and host RNA-binding proteins. We identified novel EBOV host factors, including Staufen1, which interacts with multiple viral factors and is required for efficient viral RNA synthesis. Ebola virus (EBOV) genome and mRNAs contain long, structured regions that could hijack host RNA-binding proteins to facilitate infection. We performed RNA affinity chromatography coupled with mass spectrometry to identify host proteins that bind to EBOV RNAs and identified four high-confidence proviral host factors, including Staufen1 (STAU1), which specifically binds both 3′ and 5′ extracistronic regions of the EBOV genome. We confirmed that EBOV infection rate and production of infectious particles were significantly reduced in STAU1-depleted cells. STAU1 was recruited to sites of EBOV RNA synthesis upon infection and enhanced viral RNA synthesis. Furthermore, STAU1 interacts with EBOV nucleoprotein (NP), virion protein 30 (VP30), and VP35; the latter two bridge the viral polymerase to the NP-coated genome, forming the viral ribonucleoprotein (RNP) complex. Our data indicate that STAU1 plays a critical role in EBOV replication by coordinating interactions between the viral genome and RNA synthesis machinery.
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31
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Molefe PF, Masamba P, Oyinloye BE, Mbatha LS, Meyer M, Kappo AP. Molecular Application of Aptamers in the Diagnosis and Treatment of Cancer and Communicable Diseases. Pharmaceuticals (Basel) 2018; 11:ph11040093. [PMID: 30274155 PMCID: PMC6315466 DOI: 10.3390/ph11040093] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 09/20/2018] [Accepted: 09/24/2018] [Indexed: 12/18/2022] Open
Abstract
Cancer and infectious diseases such as Ebola, HIV, tuberculosis, Zika, hepatitis, measles and human schistosomiasis are serious global health hazards. The increasing annual morbidities and mortalities of these diseases have been blamed on drug resistance and the inefficacy of available diagnostic tools, particularly those which are immunologically-based. Antibody-based tools rely solely on antibody production for diagnosis and for this reason they are the major cause of diagnostic delays. Unfortunately, the control of these diseases depends on early detection and administration of effective treatment therefore any diagnostic delay is a huge challenge to curbing these diseases. Hence, there is a need for alternative diagnostic tools, discovery and development of novel therapeutic agents. Studies have demonstrated that aptamers could potentially offer one of the best solutions to these problems. Aptamers are short sequences of either DNA or RNA molecules, which are identified in vitro through a SELEX process. They are sensitive and bind specifically to target molecules. Their promising features suggest they may serve as better diagnostic agents and can be used as drug carriers for therapeutic purposes. In this article, we review the applications of aptamers in the theranostics of cancer and some infectious diseases.
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Affiliation(s)
- Philisiwe Fortunate Molefe
- Biotechnology and Structural Biochemistry (BSB) Group, Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Zululand, KwaDlangezwa 3886, South Africa.
| | - Priscilla Masamba
- Biotechnology and Structural Biochemistry (BSB) Group, Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Zululand, KwaDlangezwa 3886, South Africa.
| | - Babatunji Emmanuel Oyinloye
- Biotechnology and Structural Biochemistry (BSB) Group, Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Zululand, KwaDlangezwa 3886, South Africa.
- Department of Biochemistry, College of Sciences, Afe Babalola University, PMB 5454, Ado-Ekiti 360001, Nigeria.
| | - Londiwe Simphiwe Mbatha
- Biotechnology and Structural Biochemistry (BSB) Group, Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Zululand, KwaDlangezwa 3886, South Africa.
| | - Mervin Meyer
- DST/Mintek Nanotechnology Innovation Centre, Biolabels Node, Department of Biotechnology, University of the Western Cape, Bellville 7535, South Africa.
| | - Abidemi Paul Kappo
- Biotechnology and Structural Biochemistry (BSB) Group, Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Zululand, KwaDlangezwa 3886, South Africa.
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32
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Martin S, Chiramel AI, Schmidt ML, Chen YC, Whitt N, Watt A, Dunham EC, Shifflett K, Traeger S, Leske A, Buehler E, Martellaro C, Brandt J, Wendt L, Müller A, Peitsch S, Best SM, Stech J, Finke S, Römer-Oberdörfer A, Groseth A, Feldmann H, Hoenen T. A genome-wide siRNA screen identifies a druggable host pathway essential for the Ebola virus life cycle. Genome Med 2018; 10:58. [PMID: 30081931 PMCID: PMC6090742 DOI: 10.1186/s13073-018-0570-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 07/13/2018] [Indexed: 01/01/2023] Open
Abstract
Background The 2014–2016 Ebola virus (EBOV) outbreak in West Africa highlighted the need for improved therapeutic options against this virus. Approaches targeting host factors/pathways essential for the virus are advantageous because they can potentially target a wide range of viruses, including newly emerging ones and because the development of resistance is less likely than when targeting the virus directly. However, systematic approaches for screening host factors important for EBOV have been hampered by the necessity to work with this virus at biosafety level 4 (BSL4). Methods In order to identify host factors involved in the EBOV life cycle, we performed a genome-wide siRNA screen comprising 64,755 individual siRNAs against 21,566 human genes to assess their activity in EBOV genome replication and transcription. As a screening platform, we used reverse genetics-based life cycle modelling systems that recapitulate these processes without the need for a BSL4 laboratory. Results Among others, we identified the de novo pyrimidine synthesis pathway as an essential host pathway for EBOV genome replication and transcription, and confirmed this using infectious EBOV under BSL4 conditions. An FDA-approved drug targeting this pathway showed antiviral activity against infectious EBOV, as well as other non-segmented negative-sense RNA viruses. Conclusions This study provides a minable data set for every human gene regarding its role in EBOV genome replication and transcription, shows that an FDA-approved drug targeting one of the identified pathways is highly efficacious in vitro, and demonstrates the power of life cycle modelling systems for conducting genome-wide host factor screens for BSL4 viruses. Electronic supplementary material The online version of this article (10.1186/s13073-018-0570-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Scott Martin
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, 31 Center Drive, Bethesda, MD, 20892, USA.,Present address: Department of Discovery Oncology, Genentech, 1 DNA Way, South San Francisco, CA, 94080, USA
| | - Abhilash I Chiramel
- Laboratory of Virology, Division of Intramural Research, National Institute for Allergy and Infectious Diseases, National Institutes of Health, 903 S 4th St., Hamilton, MT, 59840, USA
| | - Marie Luisa Schmidt
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Yu-Chi Chen
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, 31 Center Drive, Bethesda, MD, 20892, USA
| | - Nadia Whitt
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, 31 Center Drive, Bethesda, MD, 20892, USA
| | - Ari Watt
- Laboratory of Virology, Division of Intramural Research, National Institute for Allergy and Infectious Diseases, National Institutes of Health, 903 S 4th St., Hamilton, MT, 59840, USA
| | - Eric C Dunham
- Laboratory of Virology, Division of Intramural Research, National Institute for Allergy and Infectious Diseases, National Institutes of Health, 903 S 4th St., Hamilton, MT, 59840, USA
| | - Kyle Shifflett
- Laboratory of Virology, Division of Intramural Research, National Institute for Allergy and Infectious Diseases, National Institutes of Health, 903 S 4th St., Hamilton, MT, 59840, USA
| | - Shelby Traeger
- Laboratory of Virology, Division of Intramural Research, National Institute for Allergy and Infectious Diseases, National Institutes of Health, 903 S 4th St., Hamilton, MT, 59840, USA
| | - Anne Leske
- Junior Research Group Arenavirus Biology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Eugen Buehler
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, 31 Center Drive, Bethesda, MD, 20892, USA
| | - Cynthia Martellaro
- Laboratory of Virology, Division of Intramural Research, National Institute for Allergy and Infectious Diseases, National Institutes of Health, 903 S 4th St., Hamilton, MT, 59840, USA
| | - Janine Brandt
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Lisa Wendt
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Andreas Müller
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Stephanie Peitsch
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Sonja M Best
- Laboratory of Virology, Division of Intramural Research, National Institute for Allergy and Infectious Diseases, National Institutes of Health, 903 S 4th St., Hamilton, MT, 59840, USA
| | - Jürgen Stech
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Stefan Finke
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Angela Römer-Oberdörfer
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Allison Groseth
- Laboratory of Virology, Division of Intramural Research, National Institute for Allergy and Infectious Diseases, National Institutes of Health, 903 S 4th St., Hamilton, MT, 59840, USA.,Junior Research Group Arenavirus Biology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Heinz Feldmann
- Laboratory of Virology, Division of Intramural Research, National Institute for Allergy and Infectious Diseases, National Institutes of Health, 903 S 4th St., Hamilton, MT, 59840, USA
| | - Thomas Hoenen
- Laboratory of Virology, Division of Intramural Research, National Institute for Allergy and Infectious Diseases, National Institutes of Health, 903 S 4th St., Hamilton, MT, 59840, USA. .,Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald, Insel Riems, Germany.
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Martin B, Decroly É. Mécanismes d’échappement des filovirus à l’immunité innée. Med Sci (Paris) 2018; 34:671-677. [DOI: 10.1051/medsci/20183408013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Le virus Ébola est un pathogène émergent important en Afrique où il a été responsable de plusieurs épidémies de fièvres hémorragiques associées à un taux de mortalité extrêmement élevée (jusqu’à 90 %). La pathogenèse des filovirus est, entre autres, liée à une réponse antivirale inadaptée. Cette famille de virus a en effet développé des stratégies d’échappement aux mécanismes précoces de l’immunité innée. Il en résulte une réplication virale massive qui induit une réponse immunitaire inappropriée à l’origine d’une réaction inflammatoire aiguë associée au syndrome hémorragique. Dans cette revue, nous décrivons les mécanismes utilisés par les filovirus, tels que le virus Ébola, pour échapper à la réponse immunitaire innée.
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Ding Z, Fang L, Yuan S, Zhao L, Wang X, Long S, Wang M, Wang D, Foda MF, Xiao S. The nucleocapsid proteins of mouse hepatitis virus and severe acute respiratory syndrome coronavirus share the same IFN-β antagonizing mechanism: attenuation of PACT-mediated RIG-I/ MDA5 activation. Oncotarget 2018; 8:49655-49670. [PMID: 28591694 PMCID: PMC5564796 DOI: 10.18632/oncotarget.17912] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 05/01/2017] [Indexed: 01/08/2023] Open
Abstract
Coronaviruses (CoVs) are a huge threat to both humans and animals and have evolved elaborate mechanisms to antagonize interferons (IFNs). Nucleocapsid (N) protein is the most abundant viral protein in CoV-infected cells, and has been identified as an innate immunity antagonist in several CoVs, including mouse hepatitis virus (MHV) and severe acute respiratory syndrome (SARS)-CoV. However, the underlying molecular mechanism(s) remain unclear. In this study, we found that MHV N protein inhibited Sendai virus and poly(I:C)-induced IFN-β production by targeting a molecule upstream of retinoic acid-induced gene I (RIG-I) and melanoma differentiation gene 5 (MDA5). Further studies showed that both MHV and SARS-CoV N proteins directly interacted with protein activator of protein kinase R (PACT), a cellular dsRNA-binding protein that can bind to RIG-I and MDA5 to activate IFN production. The N–PACT interaction sequestered the association of PACT and RIG-I/MDA5, which in turn inhibited IFN-β production. However, the N proteins from porcine epidemic diarrhea virus (PEDV) and porcine reproductive and respiratory syndrome virus (PRRSV), which are also classified in the order Nidovirales, did not interact and counteract with PACT. Taken together, our present study confirms that both MHV and SARS-CoV N proteins can perturb the function of cellular PACT to circumvent the innate antiviral response. However, this strategy does not appear to be used by all CoVs N proteins.
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Affiliation(s)
- Zhen Ding
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
| | - Liurong Fang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
| | - Shuangling Yuan
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
| | - Ling Zhao
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
| | - Xunlei Wang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
| | - Siwen Long
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
| | - Mohan Wang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
| | - Dang Wang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
| | - Mohamed Frahat Foda
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
| | - Shaobo Xiao
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China.,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
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35
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Insights into the homo-oligomerization properties of N-terminal coiled-coil domain of Ebola virus VP35 protein. Virus Res 2018; 247:61-70. [PMID: 29427597 DOI: 10.1016/j.virusres.2018.02.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 01/30/2018] [Accepted: 02/06/2018] [Indexed: 12/31/2022]
Abstract
The multifunctional Ebola virus (EBOV) VP35 protein is a key determinant of virulence. VP35 is essential for EBOV replication, is a component of the viral RNA polymerase and participates in nucleocapsid formation. Furthermore, VP35 contributes to EBOV evasion of the host innate immune response by suppressing RNA silencing and blocking RIG-I like receptors' pathways that lead to type I interferon (IFN) production. VP35 homo-oligomerization has been reported to be critical for its replicative function and to increase its IFN-antagonism properties. Moreover, homo-oligomerization is mediated by a predicted coiled-coil (CC) domain located within its N-terminal region. Here we report the homo-oligomerization profile of full-length recombinant EBOV VP35 (rVP35) assessed by size-exclusion chromatography and native polyacrylamide gel electrophoresis. Based on our biochemical results and in agreement with previous experimental observations, we have built an in silico 3D model of the so-far structurally unsolved EBOV VP35 CC domain and performed self-assembly homo-oligomerization simulations by means of molecular dynamics. Our model advances the understanding of how VP35 may associate in different homo-oligomeric species, a crucial process for EBOV replication and pathogenicity.
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Dutta M, Robertson SJ, Okumura A, Scott DP, Chang J, Weiss JM, Sturdevant GL, Feldmann F, Haddock E, Chiramel AI, Ponia SS, Dougherty JD, Katze MG, Rasmussen AL, Best SM. A Systems Approach Reveals MAVS Signaling in Myeloid Cells as Critical for Resistance to Ebola Virus in Murine Models of Infection. Cell Rep 2017; 18:816-829. [PMID: 28099857 DOI: 10.1016/j.celrep.2016.12.069] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 11/11/2016] [Accepted: 12/20/2016] [Indexed: 01/08/2023] Open
Abstract
The unprecedented 2013-2016 outbreak of Ebola virus (EBOV) resulted in over 11,300 human deaths. Host resistance to RNA viruses requires RIG-I-like receptor (RLR) signaling through the adaptor protein, mitochondrial antiviral signaling protein (MAVS), but the role of RLR-MAVS in orchestrating anti-EBOV responses in vivo is not known. Here we apply a systems approach to MAVS-/- mice infected with either wild-type or mouse-adapted EBOV. MAVS controlled EBOV replication through the expression of IFNα, regulation of inflammatory responses in the spleen, and prevention of cell death in the liver, with macrophages implicated as a major cell type influencing host resistance. A dominant role for RLR signaling in macrophages was confirmed following conditional MAVS deletion in LysM+ myeloid cells. These findings reveal tissue-specific MAVS-dependent transcriptional pathways associated with resistance to EBOV, and they demonstrate that EBOV adaptation to cause disease in mice involves changes in two distinct events, RLR-MAVS antagonism and suppression of RLR-independent IFN-I responses.
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Affiliation(s)
- Mukta Dutta
- Department of Microbiology, School of Medicine, University of Washington, Seattle, WA 59105, USA
| | - Shelly J Robertson
- Laboratory of Virology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT 59840, USA
| | - Atsushi Okumura
- Department of Microbiology, School of Medicine, University of Washington, Seattle, WA 59105, USA; Laboratory of Virology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT 59840, USA; Center for Infection and Immunity, Mailman School of Public Health, Columbia University, New York, NY 10032, USA
| | - Dana P Scott
- Rocky Mountain Veterinary Branch, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT 59840, USA
| | - Jean Chang
- Department of Microbiology, School of Medicine, University of Washington, Seattle, WA 59105, USA
| | - Jeffrey M Weiss
- Department of Microbiology, School of Medicine, University of Washington, Seattle, WA 59105, USA
| | - Gail L Sturdevant
- Laboratory of Virology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT 59840, USA
| | - Friederike Feldmann
- Laboratory of Virology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT 59840, USA
| | - Elaine Haddock
- Laboratory of Virology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT 59840, USA
| | - Abhilash I Chiramel
- Laboratory of Virology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT 59840, USA
| | - Sanket S Ponia
- Laboratory of Virology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT 59840, USA
| | - Jonathan D Dougherty
- Laboratory of Virology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT 59840, USA
| | - Michael G Katze
- Department of Microbiology, School of Medicine, University of Washington, Seattle, WA 59105, USA
| | - Angela L Rasmussen
- Department of Microbiology, School of Medicine, University of Washington, Seattle, WA 59105, USA; Center for Infection and Immunity, Mailman School of Public Health, Columbia University, New York, NY 10032, USA
| | - Sonja M Best
- Laboratory of Virology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, MT 59840, USA.
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37
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He F, Melén K, Maljanen S, Lundberg R, Jiang M, Österlund P, Kakkola L, Julkunen I. Ebolavirus protein VP24 interferes with innate immune responses by inhibiting interferon-λ1 gene expression. Virology 2017; 509:23-34. [PMID: 28595092 DOI: 10.1016/j.virol.2017.06.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 05/25/2017] [Accepted: 06/01/2017] [Indexed: 10/19/2022]
Abstract
Ebolaviruses (EBOV) cause severe disease with a recent outbreak in West Africa in 2014-2015 leading to more than 28 000 cases and 11 300 fatalities. This emphasizes the urgent need for better knowledge on these highly pathogenic RNA viruses. Host innate immune responses play a key role in restricting the spread of a viral disease. In this study we systematically analyzed the effects of cloned EBOV genes on the main host immune response to RNA viruses: the activation of RIG-I pathway and type I and III interferon (IFN) gene expression. EBOV VP24, in addition of inhibiting IFN-induced antiviral responses, was found to efficiently inhibit type III IFN-λ1 gene expression. This inhibition was found to occur downstream of IRF3 activation and to be dependent on VP24 importin binding residues. These results emphasize the importance of VP24 in EBOV infection cycle, making VP24 as an excellent target for drug development.
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Affiliation(s)
- Felix He
- Institute of Biomedicine/Virology, University of Turku, Kiinamyllynkatu 13, 20520 Turku, Finland.
| | - Krister Melén
- Institute of Biomedicine/Virology, University of Turku, Kiinamyllynkatu 13, 20520 Turku, Finland; Expert Microbiology Unit, National Institute for Health and Welfare, Mannerheimintie 166, 00300 Helsinki, Finland.
| | - Sari Maljanen
- Institute of Biomedicine/Virology, University of Turku, Kiinamyllynkatu 13, 20520 Turku, Finland.
| | - Rickard Lundberg
- Institute of Biomedicine/Virology, University of Turku, Kiinamyllynkatu 13, 20520 Turku, Finland.
| | - Miao Jiang
- Expert Microbiology Unit, National Institute for Health and Welfare, Mannerheimintie 166, 00300 Helsinki, Finland.
| | - Pamela Österlund
- Expert Microbiology Unit, National Institute for Health and Welfare, Mannerheimintie 166, 00300 Helsinki, Finland.
| | - Laura Kakkola
- Institute of Biomedicine/Virology, University of Turku, Kiinamyllynkatu 13, 20520 Turku, Finland.
| | - Ilkka Julkunen
- Institute of Biomedicine/Virology, University of Turku, Kiinamyllynkatu 13, 20520 Turku, Finland.
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38
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An RNA polymerase II-driven Ebola virus minigenome system as an advanced tool for antiviral drug screening. Antiviral Res 2017; 146:21-27. [PMID: 28807685 DOI: 10.1016/j.antiviral.2017.08.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 08/08/2017] [Accepted: 08/09/2017] [Indexed: 11/20/2022]
Abstract
Ebola virus (EBOV) causes a severe disease in humans with the potential for significant international public health consequences. Currently, treatments are limited to experimental vaccines and therapeutics. Therefore, research into prophylaxis and antiviral strategies to combat EBOV infections is of utmost importance. The requirement for high containment laboratories to study EBOV infection is a limiting factor for conducting EBOV research. To overcome this issue, minigenome systems have been used as valuable tools to study EBOV replication and transcription mechanisms and to screen for antiviral compounds at biosafety level 2. The most commonly used EBOV minigenome system relies on the ectopic expression of the T7 RNA polymerase (T7), which can be limiting for certain cell types. We have established an improved EBOV minigenome system that utilizes endogenous RNA polymerase II (pol II) as a driver for the synthesis of minigenome RNA. We show here that this system is as efficient as the T7-based minigenome system, but works in a wider range of cell types, including biologically relevant cell types such as bat cells. Importantly, we were also able to adapt this system to a reliable and cost-effective 96-well format antiviral screening assay with a Z-factor of 0.74, indicative of a robust assay. Using this format, we identified JG40, an inhibitor of Hsp70, as an inhibitor of EBOV replication, highlighting the potential for this system as a tool for antiviral drug screening. In summary, this updated EBOV minigenome system provides a convenient and effective means of advancing the field of EBOV research.
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39
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Abstract
Two of the most important contemporary emerging viruses that affect human health in Africa are Ebola virus (EBOV) and Lassa virus (LASV). The 2013-2016 West African outbreak of EBOV was responsible for more than 11,000 deaths, primarily in Guinea, Sierra Leone and Liberia. LASV is constantly emerging in these and surrounding West African countries, with an estimate of more than 500,000 cases of Lassa fever, and approximately 5,000 deaths, annually. Both EBOV and LASV are zoonotic, and human infection often results in a severe haemorrhagic fever in both cases. However, the contribution of specific immune responses to disease differs between EBOV and LASV. This Review examines innate and adaptive immune responses to these viruses with the goal of delineating responses that are associated with protective versus pathogenic outcomes.
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40
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Groseth A, Hoenen T. Forty Years of Ebolavirus Molecular Biology: Understanding a Novel Disease Agent Through the Development and Application of New Technologies. Methods Mol Biol 2017; 1628:15-38. [PMID: 28573608 DOI: 10.1007/978-1-4939-7116-9_2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Molecular biology is a broad discipline that seeks to understand biological phenomena at a molecular level, and achieves this through the study of DNA, RNA, proteins, and/or other macromolecules (e.g., those involved in the modification of these substrates). Consequently, it relies on the availability of a wide variety of methods that deal with the collection, preservation, inactivation, separation, manipulation, imaging, and analysis of these molecules. As such the state of the art in the field of ebolavirus molecular biology research (and that of all other viruses) is largely intertwined with, if not driven by, advancements in the technical methodologies available for these kinds of studies. Here we review of the current state of our knowledge regarding ebolavirus biology and emphasize the associated methods that made these discoveries possible.
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Affiliation(s)
- Allison Groseth
- Friedrich-Loeffler-Institut, Greifswald - Insel Riems, Germany.
| | - Thomas Hoenen
- Friedrich-Loeffler-Institut, Greifswald - Insel Riems, Germany
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41
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Kirchdoerfer RN, Wasserman H, Amarasinghe GK, Saphire EO. Filovirus Structural Biology: The Molecules in the Machine. Curr Top Microbiol Immunol 2017; 411:381-417. [PMID: 28795188 DOI: 10.1007/82_2017_16] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In this chapter, we describe what is known thus far about the structures and functions of the handful of proteins encoded by filovirus genomes. Amongst the fascinating findings of the last decade is the plurality of functions and structures that these polypeptides can adopt. Many of the encoded proteins can play multiple, distinct roles in the virus life cycle, although the mechanisms by which these functions are determined and controlled remain mostly veiled. Further, some filovirus proteins are multistructural: adopting different oligomeric assemblies and sometimes, different tertiary structures to achieve their separate, and equally essential functions. Structures, and the functions they dictate, are described for components of the nucleocapsid, the matrix, and the surface and secreted glycoproteins.
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Affiliation(s)
- Robert N Kirchdoerfer
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Hal Wasserman
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Gaya K Amarasinghe
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, 63110, USA.
| | - Erica Ollmann Saphire
- Department of Immunology and Microbiology, The Scripps Research Institute, The Skaggs Institute for Chemical Biology, La Jolla, CA, 92037, USA.
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42
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Le Sage V, Cinti A, McCarthy S, Amorim R, Rao S, Daino GL, Tramontano E, Branch DR, Mouland AJ. Ebola virus VP35 blocks stress granule assembly. Virology 2016; 502:73-83. [PMID: 28013103 DOI: 10.1016/j.virol.2016.12.012] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 12/08/2016] [Accepted: 12/12/2016] [Indexed: 10/20/2022]
Abstract
Stress granules (SGs) are dynamic cytoplasmic aggregates of translationally silenced mRNAs that assemble in response to environmental stress. SGs appear to play an important role in antiviral innate immunity and many viruses have evolved to block or subvert SGs components for their own benefit. Here, we demonstrate that intracellular Ebola virus (EBOV) replication and transcription-competent virus like particles (trVLP) infection does not lead to SG assembly but leads to a blockade to Arsenite-induced SG assembly. Moreover we show that EBOV VP35 represses the assembly of canonical and non-canonical SGs induced by a variety of pharmacological stresses. This SG blockade requires, at least in part, the C-terminal domain of VP35. Furthermore, results from our co-immunoprecipitation studies indicate that VP35 interacts with multiple SG components, including G3BP1, eIF3 and eEF2 through a stress- and RNA-independent mechanism. These data suggest a novel function for EBOV VP35 in the repression of SG assembly.
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Affiliation(s)
- Valerie Le Sage
- HIV-1 RNA Trafficking Laboratory, Lady Davis Institute at the Jewish General Hospital, Montréal, Québec, Canada H3T 1E2
| | - Alessandro Cinti
- HIV-1 RNA Trafficking Laboratory, Lady Davis Institute at the Jewish General Hospital, Montréal, Québec, Canada H3T 1E2; Department of Medicine, McGill University, Montréal, Québec, Canada H3A 0G4
| | - Stephen McCarthy
- Centre for Innovation, Canadian Blood Services, Toronto, Ontario, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Ontario, Toronto, Canada
| | - Raquel Amorim
- HIV-1 RNA Trafficking Laboratory, Lady Davis Institute at the Jewish General Hospital, Montréal, Québec, Canada H3T 1E2; Department of Medicine, McGill University, Montréal, Québec, Canada H3A 0G4
| | - Shringar Rao
- HIV-1 RNA Trafficking Laboratory, Lady Davis Institute at the Jewish General Hospital, Montréal, Québec, Canada H3T 1E2; Department of Microbiology and Immunology, McGill University, Montréal, Québec, Canada H3A 0G4
| | - Gian Luca Daino
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, SS 554, 09042 Monserrato, Cagliari, Italy
| | - Enzo Tramontano
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, SS 554, 09042 Monserrato, Cagliari, Italy
| | - Donald R Branch
- Centre for Innovation, Canadian Blood Services, Toronto, Ontario, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Ontario, Toronto, Canada
| | - Andrew J Mouland
- HIV-1 RNA Trafficking Laboratory, Lady Davis Institute at the Jewish General Hospital, Montréal, Québec, Canada H3T 1E2; Department of Medicine, McGill University, Montréal, Québec, Canada H3A 0G4; Department of Microbiology and Immunology, McGill University, Montréal, Québec, Canada H3A 0G4.
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43
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Middle East Respiratory Coronavirus Accessory Protein 4a Inhibits PKR-Mediated Antiviral Stress Responses. PLoS Pathog 2016; 12:e1005982. [PMID: 27783669 PMCID: PMC5081173 DOI: 10.1371/journal.ppat.1005982] [Citation(s) in RCA: 143] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 10/06/2016] [Indexed: 02/06/2023] Open
Abstract
Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe respiratory infections that can be life-threatening. To establish an infection and spread, MERS-CoV, like most other viruses, must navigate through an intricate network of antiviral host responses. Besides the well-known type I interferon (IFN-α/β) response, the protein kinase R (PKR)-mediated stress response is being recognized as an important innate response pathway. Upon detecting viral dsRNA, PKR phosphorylates eIF2α, leading to the inhibition of cellular and viral translation and the formation of stress granules (SGs), which are increasingly recognized as platforms for antiviral signaling pathways. It is unknown whether cellular infection by MERS-CoV activates the stress response pathway or whether the virus has evolved strategies to suppress this infection-limiting pathway. Here, we show that cellular infection with MERS-CoV does not lead to the formation of SGs. By transiently expressing the MERS-CoV accessory proteins individually, we identified a role of protein 4a (p4a) in preventing activation of the stress response pathway. Expression of MERS-CoV p4a impeded dsRNA-mediated PKR activation, thereby rescuing translation inhibition and preventing SG formation. In contrast, p4a failed to suppress stress response pathway activation that is independent of PKR and dsRNA. MERS-CoV p4a is a dsRNA binding protein. Mutation of the dsRNA binding motif in p4a disrupted its PKR antagonistic activity. By inserting p4a in a picornavirus lacking its natural PKR antagonist, we showed that p4a exerts PKR antagonistic activity also under infection conditions. However, a recombinant MERS-CoV deficient in p4a expression still suppressed SG formation, indicating the expression of at least one other stress response antagonist. This virus also suppressed the dsRNA-independent stress response pathway. Thus, MERS-CoV interferes with antiviral stress responses using at least two different mechanisms, with p4a suppressing the PKR-dependent stress response pathway, probably by sequestering dsRNA. MERS-CoV p4a represents the first coronavirus stress response antagonist described.
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44
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Thi EP, Lee ACH, Geisbert JB, Ursic-Bedoya R, Agans KN, Robbins M, Deer DJ, Fenton KA, Kondratowicz AS, MacLachlan I, Geisbert TW, Mire CE. Rescue of non-human primates from advanced Sudan ebolavirus infection with lipid encapsulated siRNA. Nat Microbiol 2016; 1:16142. [PMID: 27670117 DOI: 10.1038/nmicrobiol.2016.142] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 07/14/2016] [Indexed: 02/03/2023]
Abstract
Although significant progress has been made in developing therapeutics against Zaire ebolavirus, these therapies do not protect against other Ebola species such as Sudan ebolavirus (SUDV). Here, we describe an RNA interference therapeutic comprising siRNA targeting the SUDV VP35 gene encapsulated in lipid nanoparticle (LNP) technology with increased potency beyond formulations used in TKM-Ebola clinical trials. Twenty-five rhesus monkeys were challenged with a lethal dose of SUDV. Twenty animals received siRNA-LNP beginning at 1, 2, 3, 4 or 5 days post-challenge. VP35-targeting siRNA-LNP treatment resulted in up to 100% survival, even when initiated when fever, viraemia and disease signs were evident. Treatment effectively controlled viral replication, mediating up to 4 log10 reductions after dosing. Mirroring clinical findings, a correlation between high viral loads and fatal outcome was observed, emphasizing the importance of stratifying efficacy according to viral load. In summary, strong survival benefit and rapid control of SUDV replication by VP35-targeting LNP confirm its therapeutic potential in combatting this lethal disease.
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Affiliation(s)
- Emily P Thi
- Arbutus Biopharma Corporation, Burnaby, British Columbia V5J 5J8, Canada
| | - Amy C H Lee
- Arbutus Biopharma Corporation, Burnaby, British Columbia V5J 5J8, Canada
| | - Joan B Geisbert
- Galveston National Laboratory, University of Texas Medical Branch, Galveston, Texas 77550, USA.,Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas 77555, USA
| | - Raul Ursic-Bedoya
- Arbutus Biopharma Corporation, Burnaby, British Columbia V5J 5J8, Canada
| | - Krystle N Agans
- Galveston National Laboratory, University of Texas Medical Branch, Galveston, Texas 77550, USA.,Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas 77555, USA
| | - Marjorie Robbins
- Arbutus Biopharma Corporation, Burnaby, British Columbia V5J 5J8, Canada
| | - Daniel J Deer
- Galveston National Laboratory, University of Texas Medical Branch, Galveston, Texas 77550, USA.,Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas 77555, USA
| | - Karla A Fenton
- Galveston National Laboratory, University of Texas Medical Branch, Galveston, Texas 77550, USA.,Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas 77555, USA
| | | | - Ian MacLachlan
- Arbutus Biopharma Corporation, Burnaby, British Columbia V5J 5J8, Canada
| | - Thomas W Geisbert
- Galveston National Laboratory, University of Texas Medical Branch, Galveston, Texas 77550, USA.,Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas 77555, USA
| | - Chad E Mire
- Galveston National Laboratory, University of Texas Medical Branch, Galveston, Texas 77550, USA.,Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas 77555, USA
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45
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Chatterjee S, Basler CF, Amarasinghe GK, Leung DW. Molecular Mechanisms of Innate Immune Inhibition by Non-Segmented Negative-Sense RNA Viruses. J Mol Biol 2016; 428:3467-82. [PMID: 27487481 DOI: 10.1016/j.jmb.2016.07.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 07/25/2016] [Accepted: 07/25/2016] [Indexed: 12/25/2022]
Abstract
The host innate immune system serves as the first line of defense against viral infections. Germline-encoded pattern recognition receptors detect molecular patterns associated with pathogens and activate innate immune responses. Of particular relevance to viral infections are those pattern recognition receptors that activate type I interferon responses, which establish an antiviral state. The order Mononegavirales is composed of viruses that possess single-stranded, non-segmented negative-sense (NNS) RNA genomes and are important human pathogens that consistently antagonize signaling related to type I interferon responses. NNS viruses have limited encoding capacity compared to many DNA viruses, and as a likely consequence, most open reading frames encode multifunctional viral proteins that interact with host factors in order to evade host cell defenses while promoting viral replication. In this review, we will discuss the molecular mechanisms of innate immune evasion by select NNS viruses. A greater understanding of these interactions will be critical in facilitating the development of effective therapeutics and viral countermeasures.
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Affiliation(s)
- Srirupa Chatterjee
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Christopher F Basler
- Center of Microbial Pathogenesis, Georgia State University, Atlanta, GA 30303, USA.
| | - Gaya K Amarasinghe
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Daisy W Leung
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA.
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46
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Ebola Virus Does Not Induce Stress Granule Formation during Infection and Sequesters Stress Granule Proteins within Viral Inclusions. J Virol 2016; 90:7268-7284. [PMID: 27252530 DOI: 10.1128/jvi.00459-16] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 05/25/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED A hallmark of Ebola virus (EBOV) infection is the formation of viral inclusions in the cytoplasm of infected cells. These viral inclusions contain the EBOV nucleocapsids and are sites of viral replication and nucleocapsid maturation. Although there is growing evidence that viral inclusions create a protected environment that fosters EBOV replication, little is known about their role in the host response to infection. The cellular stress response is an effective antiviral strategy that leads to stress granule (SG) formation and translational arrest mediated by the phosphorylation of a translation initiation factor, the α subunit of eukaryotic initiation factor 2 (eIF2α). Here, we show that selected SG proteins are sequestered within EBOV inclusions, where they form distinct granules that colocalize with viral RNA. These inclusion-bound (IB) granules are functionally and structurally different from canonical SGs. Formation of IB granules does not indicate translational arrest in the infected cells. We further show that EBOV does not induce formation of canonical SGs or eIF2α phosphorylation at any time postinfection but is unable to fully inhibit SG formation induced by different exogenous stressors, including sodium arsenite, heat, and hippuristanol. Despite the sequestration of SG marker proteins into IB granules, canonical SGs are unable to form within inclusions, which we propose might be mediated by a novel function of VP35, which disrupts SG formation. This function is independent of VP35's RNA binding activity. Further studies aim to reveal the mechanism for SG protein sequestration and precise function within inclusions. IMPORTANCE Although progress has been made developing antiviral therapeutics and vaccines against the highly pathogenic Ebola virus (EBOV), the cellular mechanisms involved in EBOV infection are still largely unknown. To better understand these intracellular events, we investigated the cellular stress response, an antiviral pathway manipulated by many viruses. We show that EBOV does not induce formation of stress granules (SGs) in infected cells and is therefore unrestricted by their concomitant translational arrest. We identified SG proteins sequestered within viral inclusions, which did not impair protein translation. We further show that EBOV is unable to block SG formation triggered by exogenous stress early in infection. These findings provide insight into potential targets of therapeutic intervention. Additionally, we identified a novel function of the interferon antagonist VP35, which is able to disrupt SG formation.
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47
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Dapiaggi F, Pieraccini S, Sironi M. In silico study of VP35 inhibitors: from computational alanine scanning to essential dynamics. MOLECULAR BIOSYSTEMS 2016; 11:2152-7. [PMID: 26118819 DOI: 10.1039/c5mb00348b] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In recent years the Ebola virus has spread through several countries in Africa, highlighting the need to develop new treatments for this disease and boosting a new research effort on this subject. The Ebola virus Viral Protein 35 (VP35) carries out multiple functions necessary for virus replication and infection, in particular interfering with (IFN)-α/β signaling. Recently, VP35 has been crystallized in complex with small organic molecules able to inhibit its interaction with viral nucleoproteins, thus reducing Ebola infections of cultured cells. In this work, starting from these structures, we carry out a computational study aimed at investigating the energetic and dynamical aspects of the interaction between VP35 and its ligands at the atomic level. Molecular dynamics simulations, computational alanine scanning, root mean square fluctuations bootstrap analysis and essential dynamics analysis were performed. Our results expand the experimental ones obtained in previous works, adding information about the interactions landscape with the identification of a set of new hot-spots residues exerting a critical function in the protein-ligand interaction. Moreover we characterized the dynamics of the complexes, showing that the presence of ligands modifies the overall protein dynamics as well as the behavior of particular protein segments.
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Affiliation(s)
- F Dapiaggi
- Dipartimento di Chimica, Università degli Studi di Milano, Via Golgi 19, 20133 Milano, Italy.
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48
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Radoshevich L, Dussurget O. Cytosolic Innate Immune Sensing and Signaling upon Infection. Front Microbiol 2016; 7:313. [PMID: 27014235 PMCID: PMC4789553 DOI: 10.3389/fmicb.2016.00313] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Accepted: 02/26/2016] [Indexed: 12/13/2022] Open
Abstract
Cytosolic sensing of pathogens is essential to a productive immune response. Recent reports have emphasized the importance of signaling platforms emanating from organelles and cytosolic sensors, particularly during the response to intracellular pathogens. Here, we highlight recent discoveries identifying the key mediators of nucleic acid and cyclic nucleotide sensing and discuss their importance in host defense. This review will also cover strategies evolved by pathogens to manipulate these pathways.
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Affiliation(s)
- Lilliana Radoshevich
- Unité des Interactions Bactéries-Cellules, Institut PasteurParis, France; Institut National de la Santé et de la Recherche Médicale, U604Paris, France; Institut National de la Recherche Agronomique, USC2020Paris, France
| | - Olivier Dussurget
- Unité des Interactions Bactéries-Cellules, Institut PasteurParis, France; Institut National de la Santé et de la Recherche Médicale, U604Paris, France; Institut National de la Recherche Agronomique, USC2020Paris, France; Cellule Pasteur, Université Paris Diderot, Sorbonne Paris CitéParis, France
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49
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Zhang YJ, Ding JN, Feng TT, Han JG. Exploring interaction mechanisms of the inhibitor binding to the VP35 IID region of Ebola virus by all atom molecular dynamics simulation method. Proteins 2015; 83:2263-78. [DOI: 10.1002/prot.24945] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 09/26/2015] [Accepted: 10/11/2015] [Indexed: 12/12/2022]
Affiliation(s)
- Yan-Jun Zhang
- National Synchrotron Radiation Laboratory; University of Science and Technology of China; Hefei 230029 People's Republic of China
| | - Jing-Na Ding
- National Synchrotron Radiation Laboratory; University of Science and Technology of China; Hefei 230029 People's Republic of China
- Anqing Medical College; b) 1588 Jixian North Rd Anqing 246052 People's Republic of China
| | - Ting-Ting Feng
- National Synchrotron Radiation Laboratory; University of Science and Technology of China; Hefei 230029 People's Republic of China
| | - Ju-Guang Han
- National Synchrotron Radiation Laboratory; University of Science and Technology of China; Hefei 230029 People's Republic of China
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50
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Messaoudi I, Amarasinghe GK, Basler CF. Filovirus pathogenesis and immune evasion: insights from Ebola virus and Marburg virus. Nat Rev Microbiol 2015; 13:663-76. [PMID: 26439085 DOI: 10.1038/nrmicro3524] [Citation(s) in RCA: 171] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Ebola viruses and Marburg viruses, members of the filovirus family, are zoonotic pathogens that cause severe disease in people, as highlighted by the latest Ebola virus epidemic in West Africa. Filovirus disease is characterized by uncontrolled virus replication and the activation of host responses that contribute to pathogenesis. Underlying these phenomena is the potent suppression of host innate antiviral responses, particularly the type I interferon response, by viral proteins, which allows high levels of viral replication. In this Review, we describe the mechanisms used by filoviruses to block host innate immunity and discuss the links between immune evasion and filovirus pathogenesis.
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Affiliation(s)
- Ilhem Messaoudi
- School of Medicine, University of California Riverside, Riverside, California 92521, USA
| | - Gaya K Amarasinghe
- The Division of Biology &Biomedical Sciences, Washington University in St. Louis, St. Louis, Missouri 63110, USA
| | - Christopher F Basler
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
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