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Bodmer BS, Hoenen T, Wendt L. Molecular insights into the Ebola virus life cycle. Nat Microbiol 2024; 9:1417-1426. [PMID: 38783022 DOI: 10.1038/s41564-024-01703-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 04/17/2024] [Indexed: 05/25/2024]
Abstract
Ebola virus and other orthoebolaviruses cause severe haemorrhagic fevers in humans, with very high case fatality rates. Their non-segmented single-stranded RNA genome encodes only seven structural proteins and a small number of non-structural proteins to facilitate the virus life cycle. The basics of this life cycle are well established, but recent advances have substantially increased our understanding of its molecular details, including the viral and host factors involved. Here we provide a comprehensive overview of our current knowledge of the molecular details of the orthoebolavirus life cycle, with a special focus on proviral host factors. We discuss the multistep entry process, viral RNA synthesis in specialized phase-separated intracellular compartments called inclusion bodies, the expression of viral proteins and ultimately the assembly of new virus particles and their release at the cell surface. In doing so, we integrate recent studies into the increasingly detailed model that has developed for these fundamental aspects of orthoebolavirus biology.
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Affiliation(s)
- Bianca S Bodmer
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald - Insel Riems, Germany
| | - Thomas Hoenen
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald - Insel Riems, Germany.
| | - Lisa Wendt
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald - Insel Riems, Germany
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2
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Małkowska P, Niedźwiedzka-Rystwej P. Factors affecting RIG-I-Like receptors activation - New research direction for viral hemorrhagic fevers. Front Immunol 2022; 13:1010635. [PMID: 36248895 PMCID: PMC9557057 DOI: 10.3389/fimmu.2022.1010635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 09/13/2022] [Indexed: 11/13/2022] Open
Abstract
Viral hemorrhagic fever (VHF) is a term referring to a group of life-threatening infections caused by several virus families (Arenaviridae, Bunyaviridae, Filoviridae and Flaviviridae). Depending on the virus, the infection can be mild and can be also characterized by an acute course with fever accompanied by hypervolemia and coagulopathy, resulting in bleeding and shock. It has been suggested that the course of the disease is strongly influenced by the activation of signaling pathways leading to RIG-I-like receptor-dependent interferon production. RIG-I-like receptors (RLRs) are one of two major receptor families that detect viral nucleic acid. RLR receptor activation is influenced by a number of factors that may have a key role in the differences that occur during the antiviral immune response in VHF. In the present study, we collected data on RLR receptors in viral hemorrhagic fevers and described factors that may influence the activation of the antiviral response. RLR receptors seem to be a good target for VHF research, which may contribute to better therapeutic and diagnostic strategies. However, due to the difficulty of conducting such studies in humans, we suggest using Lagovirus europaeus as an animal model for VHF.
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Affiliation(s)
- Paulina Małkowska
- Doctoral School, University of Szczecin, Szczecin, Poland
- Institute of Biology, University of Szczecin, Szczecin, Poland
- *Correspondence: Paulina Małkowska,
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3
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Hargreaves A, Brady C, Mellors J, Tipton T, Carroll MW, Longet S. Filovirus Neutralising Antibodies: Mechanisms of Action and Therapeutic Application. Pathogens 2021; 10:pathogens10091201. [PMID: 34578233 PMCID: PMC8468515 DOI: 10.3390/pathogens10091201] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 09/10/2021] [Accepted: 09/12/2021] [Indexed: 12/02/2022] Open
Abstract
Filoviruses, especially Ebola virus, cause sporadic outbreaks of viral haemorrhagic fever with very high case fatality rates in Africa. The 2013–2016 Ebola epidemic in West Africa provided large survivor cohorts spurring a large number of human studies which showed that specific neutralising antibodies played a key role in protection following a natural Ebola virus infection, as part of the overall humoral response and in conjunction with the cellular adaptive response. This review will discuss the studies in survivors and animal models which described protective neutralising antibody response. Their mechanisms of action will be detailed. Furthermore, the importance of neutralising antibodies in antibody-based therapeutics and in vaccine-induced responses will be explained, as well as the strategies to avoid immune escape from neutralising antibodies. Understanding the neutralising antibody response in the context of filoviruses is crucial to furthering our understanding of virus structure and function, in addition to improving current vaccines & antibody-based therapeutics.
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Affiliation(s)
- Alexander Hargreaves
- Nuffield Department of Medicine, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK; (A.H.); (C.B.); (J.M.); (T.T.); (M.W.C.)
- Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK
| | - Caolann Brady
- Nuffield Department of Medicine, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK; (A.H.); (C.B.); (J.M.); (T.T.); (M.W.C.)
| | - Jack Mellors
- Nuffield Department of Medicine, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK; (A.H.); (C.B.); (J.M.); (T.T.); (M.W.C.)
- National Infection Service, Public Health England, Porton Down, Salisbury SP4 0JG, UK
- Department of Infection Biology, Institute of Infection and Global Health, University of Liverpool, Liverpool L69 7ZX, UK
| | - Tom Tipton
- Nuffield Department of Medicine, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK; (A.H.); (C.B.); (J.M.); (T.T.); (M.W.C.)
| | - Miles W. Carroll
- Nuffield Department of Medicine, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK; (A.H.); (C.B.); (J.M.); (T.T.); (M.W.C.)
- National Infection Service, Public Health England, Porton Down, Salisbury SP4 0JG, UK
| | - Stephanie Longet
- Nuffield Department of Medicine, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK; (A.H.); (C.B.); (J.M.); (T.T.); (M.W.C.)
- Correspondence: ; Tel.: +44-18-6561-7892
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4
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Diallo I, Ho J, Laffont B, Laugier J, Benmoussa A, Lambert M, Husseini Z, Soule G, Kozak R, Kobinger GP, Provost P. Altered microRNA Transcriptome in Cultured Human Liver Cells upon Infection with Ebola Virus. Int J Mol Sci 2021; 22:ijms22073792. [PMID: 33917562 PMCID: PMC8038836 DOI: 10.3390/ijms22073792] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 03/27/2021] [Accepted: 03/30/2021] [Indexed: 02/07/2023] Open
Abstract
Ebola virus (EBOV) is a virulent pathogen, notorious for inducing life-threatening hemorrhagic fever, that has been responsible for several outbreaks in Africa and remains a public health threat. Yet, its pathogenesis is still not completely understood. Although there have been numerous studies on host transcriptional response to EBOV, with an emphasis on the clinical features, the impact of EBOV infection on post-transcriptional regulatory elements, such as microRNAs (miRNAs), remains largely unexplored. MiRNAs are involved in inflammation and immunity and are believed to be important modulators of the host response to viral infection. Here, we have used small RNA sequencing (sRNA-Seq), qPCR and functional analyses to obtain the first comparative miRNA transcriptome (miRNome) of a human liver cell line (Huh7) infected with one of the following three EBOV strains: Mayinga (responsible for the first Zaire outbreak in 1976), Makona (responsible for the West Africa outbreak in 2013–2016) and the epizootic Reston (presumably innocuous to humans). Our results highlight specific miRNA-based immunity pathways and substantial differences between the strains beyond their clinical manifestation and pathogenicity. These analyses shed new light into the molecular signature of liver cells upon EBOV infection and reveal new insights into miRNA-based virus attack and host defense strategy.
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Affiliation(s)
- Idrissa Diallo
- CHU de Québec Research Center, Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université Laval, Quebec, QC G1V 4G2, Canada; (I.D.); (J.H.); (B.L.); (J.L.); (A.B.); (M.L.); (Z.H.); (G.P.K.)
| | - Jeffrey Ho
- CHU de Québec Research Center, Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université Laval, Quebec, QC G1V 4G2, Canada; (I.D.); (J.H.); (B.L.); (J.L.); (A.B.); (M.L.); (Z.H.); (G.P.K.)
| | - Benoit Laffont
- CHU de Québec Research Center, Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université Laval, Quebec, QC G1V 4G2, Canada; (I.D.); (J.H.); (B.L.); (J.L.); (A.B.); (M.L.); (Z.H.); (G.P.K.)
| | - Jonathan Laugier
- CHU de Québec Research Center, Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université Laval, Quebec, QC G1V 4G2, Canada; (I.D.); (J.H.); (B.L.); (J.L.); (A.B.); (M.L.); (Z.H.); (G.P.K.)
| | - Abderrahim Benmoussa
- CHU de Québec Research Center, Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université Laval, Quebec, QC G1V 4G2, Canada; (I.D.); (J.H.); (B.L.); (J.L.); (A.B.); (M.L.); (Z.H.); (G.P.K.)
| | - Marine Lambert
- CHU de Québec Research Center, Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université Laval, Quebec, QC G1V 4G2, Canada; (I.D.); (J.H.); (B.L.); (J.L.); (A.B.); (M.L.); (Z.H.); (G.P.K.)
| | - Zeinab Husseini
- CHU de Québec Research Center, Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université Laval, Quebec, QC G1V 4G2, Canada; (I.D.); (J.H.); (B.L.); (J.L.); (A.B.); (M.L.); (Z.H.); (G.P.K.)
| | - Geoff Soule
- Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB R3B 3M9, Canada; (G.S.); (R.K.)
| | - Robert Kozak
- Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB R3B 3M9, Canada; (G.S.); (R.K.)
- Division of Microbiology, Department of Laboratory Medicine & Molecular Diagnostics, Sunnybrook Health Sciences Centre, Toronto, ON M4N 3M5, Canada
| | - Gary P. Kobinger
- CHU de Québec Research Center, Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université Laval, Quebec, QC G1V 4G2, Canada; (I.D.); (J.H.); (B.L.); (J.L.); (A.B.); (M.L.); (Z.H.); (G.P.K.)
- Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB R3B 3M9, Canada; (G.S.); (R.K.)
- Département de Microbiologie Médicale, Université du Manitoba, Winnipeg, MB R3E 0J9, Canada
| | - Patrick Provost
- CHU de Québec Research Center, Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université Laval, Quebec, QC G1V 4G2, Canada; (I.D.); (J.H.); (B.L.); (J.L.); (A.B.); (M.L.); (Z.H.); (G.P.K.)
- CHUQ Research Center/CHUL Pavilion, 2705 Blvd Laurier, Room T1-65, Quebec, QC G1V 4G2, Canada
- Correspondence: ; Tel.: +1-418-525-4444 (ext. 48842)
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5
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Jain S, Khaiboullina SF, Baranwal M. Immunological Perspective for Ebola Virus Infection and Various Treatment Measures Taken to Fight the Disease. Pathogens 2020; 9:E850. [PMID: 33080902 PMCID: PMC7603231 DOI: 10.3390/pathogens9100850] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 10/07/2020] [Accepted: 10/16/2020] [Indexed: 12/19/2022] Open
Abstract
Ebolaviruses, discovered in 1976, belongs to the Filoviridae family, which also includes Marburg and Lloviu viruses. They are negative-stranded RNA viruses with six known species identified to date. Ebola virus (EBOV) is a member of Zaire ebolavirus species and can cause the Ebola virus disease (EVD), an emerging zoonotic disease that results in homeostatic imbalance and multi-organ failure. There are three EBOV outbreaks documented in the last six years resulting in significant morbidity (> 32,000 cases) and mortality (> 13,500 deaths). The potential factors contributing to the high infectivity of this virus include multiple entry mechanisms, susceptibility of the host cells, employment of multiple immune evasion mechanisms and rapid person-to-person transmission. EBOV infection leads to cytokine storm, disseminated intravascular coagulation, host T cell apoptosis as well as cell mediated and humoral immune response. In this review, a concise recap of cell types targeted by EBOV and EVD symptoms followed by detailed run-through of host innate and adaptive immune responses, virus-driven regulation and their combined effects contributing to the disease pathogenesis has been presented. At last, the vaccine and drug development initiatives as well as challenges related to the management of infection have been discussed.
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Affiliation(s)
- Sahil Jain
- Department of Biotechnology, Thapar Institute of Engineering & Technology, Patiala 147004, Punjab, India;
| | - Svetlana F. Khaiboullina
- Department of Microbiology and Immunology, University of Nevada, Reno, NV 89557, USA
- Institute of Fundamental Medicine and Biology, Kazan Federal University, 420008 Kazan, Tatarstan, Russia
| | - Manoj Baranwal
- Department of Biotechnology, Thapar Institute of Engineering & Technology, Patiala 147004, Punjab, India;
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Woolsey C, Menicucci AR, Cross RW, Luthra P, Agans KN, Borisevich V, Geisbert JB, Mire CE, Fenton KA, Jankeel A, Anand S, Ebihara H, Geisbert TW, Messaoudi I, Basler CF. A VP35 Mutant Ebola Virus Lacks Virulence but Can Elicit Protective Immunity to Wild-Type Virus Challenge. Cell Rep 2020; 28:3032-3046.e6. [PMID: 31533029 DOI: 10.1016/j.celrep.2019.08.047] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 06/20/2019] [Accepted: 08/13/2019] [Indexed: 12/25/2022] Open
Abstract
Zaire ebolavirus (EBOV) VP35 protein is a suppressor of type I interferon (IFN) production, an inhibitor of dendritic cell maturation, and a putative virulence determinant. Here, a recombinant EBOV encoding a mutant VP35 virus (VP35m) is demonstrated to activate RIG-I-like receptor signaling and innate antiviral pathways. When inoculated into cynomolgus macaques, VP35m exhibits dramatic attenuation as compared to wild-type EBOV (wtEBOV), with 20 or 300 times the standard 100% lethal challenge dose not causing EBOV disease (EVD). Further, VP35m infection, despite limited replication in vivo, activates antigen presentation and innate immunity pathways and elicits increased frequencies of proliferating memory T cells and B cells and production of anti-EBOV antibodies. Upon wtEBOV challenge, VP35m-immunized animals survive, exhibiting host responses consistent with an orderly immune response and the absence of excessive inflammation. These data demonstrate that VP35 is a critical EBOV immune evasion factor and provide insights into immune mechanisms of EBOV control.
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Affiliation(s)
- Courtney Woolsey
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA; Galveston National Laboratory, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Andrea R Menicucci
- Department of Molecular Biology and Biochemistry, College of Biological Sciences, University of California, Irvine, Irvine, CA 92697, USA
| | - Robert W Cross
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA; Galveston National Laboratory, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Priya Luthra
- Center for Microbial Pathogenesis, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA 30303, USA
| | - Krystle N Agans
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA; Galveston National Laboratory, 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; Galveston National Laboratory, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Joan B Geisbert
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA; Galveston National Laboratory, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Chad E Mire
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA; Galveston National Laboratory, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Karla A Fenton
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA; Galveston National Laboratory, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Allen Jankeel
- Department of Molecular Biology and Biochemistry, College of Biological Sciences, University of California, Irvine, Irvine, CA 92697, USA
| | - Sneha Anand
- Department of Molecular Biology and Biochemistry, College of Biological Sciences, University of California, Irvine, Irvine, CA 92697, USA
| | - Hideki Ebihara
- Department of Molecular Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | - Thomas W Geisbert
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA; Galveston National Laboratory, University of Texas Medical Branch, Galveston, TX 77555, USA.
| | - Ilhem Messaoudi
- Department of Molecular Biology and Biochemistry, College of Biological Sciences, University of California, Irvine, Irvine, CA 92697, USA.
| | - Christopher F Basler
- Center for Microbial Pathogenesis, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA 30303, USA.
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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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8
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Pavlovich SS, Darling T, Hume AJ, Davey RA, Feng F, Mühlberger E, Kepler TB. Egyptian Rousette IFN-ω Subtypes Elicit Distinct Antiviral Effects and Transcriptional Responses in Conspecific Cells. Front Immunol 2020; 11:435. [PMID: 32231668 PMCID: PMC7083018 DOI: 10.3389/fimmu.2020.00435] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 02/25/2020] [Indexed: 12/15/2022] Open
Abstract
Bats host a number of viruses that cause severe disease in humans without experiencing overt symptoms of disease themselves. While the mechanisms underlying this ability to avoid sickness are not known, deep sequencing studies of bat genomes have uncovered genetic adaptations that may have functional importance in the antiviral response of these animals. Egyptian rousette bats (Rousettus aegyptiacus) are the natural reservoir hosts of Marburg virus (MARV). In contrast to humans, these bats do not become sick when infected with MARV. A striking difference to the human genome is that Egyptian rousettes have an expanded repertoire of IFNW genes. To probe the biological implications of this expansion, we synthesized IFN-ω4 and IFN-ω9 proteins and tested their antiviral activity in Egyptian rousette cells. Both IFN-ω4 and IFN-ω9 showed antiviral activity against RNA viruses, including MARV, with IFN-ω9 being more efficient than IFN-ω4. Using RNA-Seq, we examined the transcriptional response induced by each protein. Although the sets of genes induced by the two IFNs were largely overlapping, IFN-ω9 induced a more rapid and intense response than did IFN-ω4. About 13% of genes induced by IFN-ω treatment are not found in the Interferome or other ISG databases, indicating that they may be uniquely IFN-responsive in this bat.
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Affiliation(s)
- Stephanie S Pavlovich
- Department of Microbiology, Boston University School of Medicine, Boston, MA, United States.,National Emerging Infectious Diseases Laboratory, Boston University, Boston, MA, United States
| | - Tamarand Darling
- Department of Virology and Immunology, Texas Biomedical Research Institute, San Antonio, TX, United States
| | - Adam J Hume
- Department of Microbiology, Boston University School of Medicine, Boston, MA, United States.,Department of Virology and Immunology, Texas Biomedical Research Institute, San Antonio, TX, United States
| | - Robert A Davey
- Department of Microbiology, Boston University School of Medicine, Boston, MA, United States.,National Emerging Infectious Diseases Laboratory, Boston University, Boston, MA, United States.,Department of Virology and Immunology, Texas Biomedical Research Institute, San Antonio, TX, United States
| | - Feng Feng
- Department of Microbiology, Boston University School of Medicine, Boston, MA, United States
| | - Elke Mühlberger
- Department of Microbiology, Boston University School of Medicine, Boston, MA, United States.,National Emerging Infectious Diseases Laboratory, Boston University, Boston, MA, United States
| | - Thomas B Kepler
- Department of Microbiology, Boston University School of Medicine, Boston, MA, United States.,National Emerging Infectious Diseases Laboratory, Boston University, Boston, MA, United States.,Department of Mathematics and Statistics, Boston University, Boston, MA, United States
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9
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Hume AJ, Mühlberger E. Distinct Genome Replication and Transcription Strategies within the Growing Filovirus Family. J Mol Biol 2019; 431:4290-4320. [PMID: 31260690 PMCID: PMC6879820 DOI: 10.1016/j.jmb.2019.06.029] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 05/31/2019] [Accepted: 06/24/2019] [Indexed: 11/18/2022]
Abstract
Research on filoviruses has historically focused on the highly pathogenic ebola- and marburgviruses. Indeed, until recently, these were the only two genera in the filovirus family. Recent advances in sequencing technologies have facilitated the discovery of not only a new ebolavirus, but also three new filovirus genera and a sixth proposed genus. While two of these new genera are similar to the ebola- and marburgviruses, the other two, discovered in saltwater fishes, are considerably more diverse. Nonetheless, these viruses retain a number of key features of the other filoviruses. Here, we review the key characteristics of filovirus replication and transcription, highlighting similarities and differences between the viruses. In particular, we focus on key regulatory elements in the genomes, replication and transcription strategies, and the conservation of protein domains and functions among the viruses. In addition, using computational analyses, we were able to identify potential homology and functions for some of the genes of the novel filoviruses with previously unknown functions. Although none of the newly discovered filoviruses have yet been isolated, initial studies of some of these viruses using minigenome systems have yielded insights into their mechanisms of replication and transcription. In general, the Cuevavirus and proposed Dianlovirus genera appear to follow the transcription and replication strategies employed by the ebola- and marburgviruses, respectively. While our knowledge of the fish filoviruses is currently limited to sequence analysis, the lack of certain conserved motifs and even entire genes necessitates that they have evolved distinct mechanisms of replication and transcription.
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Affiliation(s)
- Adam J Hume
- Department of Microbiology, Boston University School of Medicine, Boston, MA 02118, USA; National Emerging Infectious Diseases Laboratories, Boston University, Boston, MA 02118, USA
| | - Elke Mühlberger
- Department of Microbiology, Boston University School of Medicine, Boston, MA 02118, USA; National Emerging Infectious Diseases Laboratories, Boston University, Boston, MA 02118, USA.
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10
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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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11
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Escaffre O, Juelich TL, Freiberg AN. Polyphenylene carboxymethylene (PPCM) in vitro antiviral efficacy against Ebola virus in the context of a sexually transmitted infection. Antiviral Res 2019; 170:104567. [PMID: 31351092 DOI: 10.1016/j.antiviral.2019.104567] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/16/2019] [Accepted: 07/22/2019] [Indexed: 12/12/2022]
Abstract
Ebola virus disease (EVD) is caused by Ebola virus (EBOV) and characterized in humans by hemorrhagic fever with high fatality rates. Human-to-human EBOV transmission occurs by physical contact with infected body fluids, or indirectly by contaminated surfaces. Sexual transmission is a route of infection only recently documented despite isolating EBOV virus or genome in the semen since 1976. Data on dissemination of EBOV from survivors remain limited and EBOV pathogenesis in humans following sexual transmission is unknown. The in vitro antiviral efficacy of polyphenylene carboxymethylene (PPCM) against EBOV was investigated considering the limited countermeasures available to block infection through sexual intercourse. PPCM is a vaginal topical contraceptive microbicide shown to prevent sexual transmission of HIV, herpes virus, and bacterial infections in several different models. Here we demonstrate its antiviral activity against EBOV. No viral replication was detected in the presence of PPCM in cell culture, including vaginal epithelial (VK2/E6E7) cells. Specifically, PPCM reduced viral attachment to cells by interfering with EBOV glycoprotein, and possibly through binding the cell surface glycosaminoglycan heparan sulfate important in the infection process. EBOV-infected VK2/E6E7 cells were found to secrete type III interferon (IFN), suggesting activation of distinct PRRs or downstream signaling factors from those required for type I and II IFN. The addition of PPCM following cell infection prevented notably the increase of these inflammation markers. Therefore, PPCM could potentially be used as a topical microbicide to reduce transmission by EBOV-positive survivors during sexual intercourse.
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Affiliation(s)
| | | | - Alexander N Freiberg
- Department of Pathology, Galveston, TX, 77555, USA; Center for Biodefense and Emerging Infectious Diseases, Galveston, TX, 77555, USA; Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, 77555, USA.
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12
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Abstract
Marburgviruses are closely related to ebolaviruses and cause a devastating disease in humans. In 2012, we published a comprehensive review of the first 45 years of research on marburgviruses and the disease they cause, ranging from molecular biology to ecology. Spurred in part by the deadly Ebola virus outbreak in West Africa in 2013-2016, research on all filoviruses has intensified. Not meant as an introduction to marburgviruses, this article instead provides a synopsis of recent progress in marburgvirus research with a particular focus on molecular biology, advances in animal modeling, and the use of Egyptian fruit bats in infection experiments.
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Affiliation(s)
- Judith Olejnik
- Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, 02118, USA.,National Emerging Infectious Diseases Laboratories, Boston University, Boston, Massachusetts, 02118, USA
| | - Elke Mühlberger
- Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, 02118, USA.,National Emerging Infectious Diseases Laboratories, Boston University, Boston, Massachusetts, 02118, USA
| | - Adam J Hume
- Department of Microbiology, Boston University School of Medicine, Boston, Massachusetts, 02118, USA.,National Emerging Infectious Diseases Laboratories, Boston University, Boston, Massachusetts, 02118, USA
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13
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Edwards MR, Basler CF. Current status of small molecule drug development for Ebola virus and other filoviruses. Curr Opin Virol 2019; 35:42-56. [PMID: 31003196 PMCID: PMC6556423 DOI: 10.1016/j.coviro.2019.03.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 03/12/2019] [Indexed: 12/16/2022]
Abstract
The filovirus family includes some of the deadliest viruses known, including Ebola virus and Marburg virus. These viruses cause periodic outbreaks of severe disease that can be spread from person to person, making the filoviruses important public health threats. There remains a need for approved drugs that target all or most members of this virus family. Small molecule inhibitors that target conserved functions hold promise as pan-filovirus therapeutics. To date, compounds that effectively target virus entry, genome replication, gene expression, and virus egress have been described. The most advanced inhibitors are nucleoside analogs that target viral RNA synthesis reactions.
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Affiliation(s)
- Megan R Edwards
- Center for Microbial Pathogenesis, Institute for Biomedical Sciences, Georgia State University, United States
| | - Christopher F Basler
- Center for Microbial Pathogenesis, Institute for Biomedical Sciences, Georgia State University, United States.
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14
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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: 7] [Impact Index Per Article: 1.4] [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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15
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Chanthamontri CK, Jordan DS, Wang W, Wu C, Lin Y, Brett TJ, Gross ML, Leung DW. The Ebola Viral Protein 35 N-Terminus Is a Parallel Tetramer. Biochemistry 2019; 58:657-664. [PMID: 30592210 DOI: 10.1021/acs.biochem.8b01154] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Members of Mononegavirales, the order that includes nonsegmented negative sense RNA viruses (NNSVs), encode a small number of multifunctional proteins. In members of the Filoviridae family, virus protein 35 (VP35) facilitates immune evasion and functions as an obligatory cofactor for viral RNA synthesis. VP35 functions in a manner orthologous to that of phosphoproteins from other NNSVs. Although the critical roles of Ebola viral VP35 (eVP35) in immune evasion and RNA synthesis are well-appreciated, a complete understanding of its organization and its role in carrying out its many functions has yet to be fully realized. In particular, we currently lack information about the role of the oligomerization domain within eVP35. To address this limitation, we report here an investigation of the oligomer structure of eVP35 using hybrid methods that include multiangle light scattering, small-angle X-ray scattering, and cross-linking coupled with mass spectrometry to determine the shape and orientation of the eVP35 oligomer. Our integrative results are consistent with a parallel tetramer in which the N-terminal regions that are required for RNA synthesis are all oriented in the same direction. Furthermore, these results define a framework for targeting the symmetric tetramer for structure-based antiviral discovery.
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Affiliation(s)
- Chamnongsak Ken Chanthamontri
- Department of Chemistry , Washington University in St. Louis , Box 1134, One Brookings Drive , St. Louis , Missouri 63130 , United States
| | - David S Jordan
- Department of Pathology and Immunology , Washington University School of Medicine in St. Louis , St. Louis , Missouri 63110 , United States
| | - Wenjie Wang
- Department of Pathology and Immunology , Washington University School of Medicine in St. Louis , St. Louis , Missouri 63110 , United States
| | - Chao Wu
- Department of Pathology and Immunology , Washington University School of Medicine in St. Louis , St. Louis , Missouri 63110 , United States
| | - Yanchun Lin
- Department of Chemistry , Washington University in St. Louis , Box 1134, One Brookings Drive , St. Louis , Missouri 63130 , United States
| | - Tom J Brett
- Department of Medicine , Washington University School of Medicine in St. Louis , St. Louis , Missouri 63110 , United States
| | - Michael L Gross
- Department of Chemistry , Washington University in St. Louis , Box 1134, One Brookings Drive , St. Louis , Missouri 63130 , United States
| | - Daisy W Leung
- Department of Pathology and Immunology , Washington University School of Medicine in St. Louis , St. Louis , Missouri 63110 , United States
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16
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Basler CF, Krogan NJ, Leung DW, Amarasinghe GK. Virus and host interactions critical for filoviral RNA synthesis as therapeutic targets. Antiviral Res 2018; 162:90-100. [PMID: 30550800 DOI: 10.1016/j.antiviral.2018.12.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 12/05/2018] [Accepted: 12/08/2018] [Indexed: 01/24/2023]
Abstract
Filoviruses, which include Ebola virus (EBOV) and Marburg virus, are negative-sense RNA viruses associated with sporadic outbreaks of severe viral hemorrhagic fever characterized by uncontrolled virus replication. The extreme virulence and emerging nature of these zoonotic pathogens make them a significant threat to human health. Replication of the filovirus genome and production of viral RNAs require the function of a complex of four viral proteins, the nucleoprotein (NP), viral protein 35 (VP35), viral protein 30 (VP30) and large protein (L). The latter performs the enzymatic activities required for production of viral RNAs and capping of viral mRNAs. Although it has been recognized that interactions between the virus-encoded components of the EBOV RNA polymerase complex are required for viral RNA synthesis reactions, specific molecular details have, until recently, been lacking. New efforts have combined structural biology and molecular virology to reveal in great detail the molecular basis for critical protein-protein interactions (PPIs) necessary for viral RNA synthesis. These efforts include recent studies that have identified a range of interacting host factors and in some instances demonstrated unique mechanisms by which they act. For a select number of these interactions, combined use of mutagenesis, over-expressing of peptides corresponding to PPI interfaces and identification of small molecules that disrupt PPIs have demonstrated the functional significance of virus-virus and virus-host PPIs and suggest several as potential targets for therapeutic intervention.
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Affiliation(s)
- Christopher F Basler
- Center for Microbial Pathogenesis, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA 30303, USA.
| | - Nevan J Krogan
- Quantitative Biosciences Institute (QBI), UCSF, San Francisco, CA, USA; Gladstone Institute of Data Science and Biotechnology, J. David Gladstone Institutes, San Francisco, CA, USA; Department of Cellular and Molecular Pharmacology, UCSF, San Francisco, CA, USA
| | - Daisy W Leung
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Gaya K Amarasinghe
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
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17
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McElroy AK, Mühlberger E, Muñoz-Fontela C. Immune barriers of Ebola virus infection. Curr Opin Virol 2018; 28:152-160. [PMID: 29452995 PMCID: PMC5886007 DOI: 10.1016/j.coviro.2018.01.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 01/23/2018] [Accepted: 01/26/2018] [Indexed: 01/10/2023]
Abstract
Since its initial emergence in 1976 in northern Democratic Republic of Congo (DRC), Ebola virus (EBOV) has been a global health concern due to its virulence in humans, the mystery surrounding the identity of its host reservoir and the unpredictable nature of Ebola virus disease (EVD) outbreaks. Early after the first clinical descriptions of a disease resembling a 'septic-shock-like syndrome', with coagulation abnormalities and multi-system organ failure, researchers began to evaluate the role of the host immune response in EVD pathophysiology. In this review, we summarize how data gathered during the last 40 years in the laboratory as well as in the field have provided insight into EBOV immunity. From molecular mechanisms involved in EBOV recognition in infected cells, to antigen processing and adaptive immune responses, we discuss current knowledge on the main immune barriers of infection as well as outstanding research questions.
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Affiliation(s)
- Anita K McElroy
- Division of Pediatric Infectious Disease, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh of UPMC, 3501 Fifth Ave, Pittsburgh, PA 15261, USA
| | - Elke Mühlberger
- Department of Microbiology and National Emerging Infectious Diseases Laboratories, Boston University School of Medicine, 620 Albany Street, 02118 Boston, MA, USA
| | - César Muñoz-Fontela
- Bernhard Nocht Institute for Tropical Medicine, Bernhard Nocht Strasse 74, 20359 Hamburg, Germany; German Center for Infection Research (DZIF), Partner Site Hamburg, Germany.
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