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Li X, Yang Y, López CB. Indiscriminate activities of different henipavirus polymerase complex proteins allow for efficient minigenome replication in hybrid systems. J Virol 2024:e0050324. [PMID: 38780245 DOI: 10.1128/jvi.00503-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2024] [Accepted: 04/24/2024] [Indexed: 05/25/2024] Open
Abstract
The henipaviruses, including Nipah virus (NiV) and Hendra virus (HeV), are biosafety level 4 (BSL-4) zoonotic pathogens that cause severe neurological and respiratory disease in humans. To study the replication machinery of these viruses, we developed robust minigenome systems that can be safely used in BSL-2 conditions. The nucleocapsid (N), phosphoprotein (P), and large protein (L) of henipaviruses are critical elements of their replication machinery and thus essential support components of the minigenome systems. Here, we tested the effects of diverse combinations of the replication support proteins on the replication capacity of the NiV and HeV minigenomes by exchanging the helper plasmids coding for these proteins among the two viruses. We demonstrate that all combinations including one or more heterologous proteins were capable of replicating both the NiV and HeV minigenomes. Sequence alignment showed identities of 92% for the N protein, 67% for P, and 87% for L. Notably, variations in amino acid residues were not concentrated in the N-P and P-L interacting regions implying that dissimilarities in amino acid composition among NiV and HeV polymerase complex proteins may not impact their interactions. The observed indiscriminate activity of NiV and HeV polymerase complex proteins is different from related viruses, which can support the replication of heterologous genomes only when the whole polymerase complex belongs to the same virus. This newly observed promiscuous property of the henipavirus polymerase complex proteins likely attributed to their conserved interaction regions could potentially be harnessed to develop universal anti-henipavirus antivirals.IMPORTANCEGiven the severity of disease induced by Hendra and Nipah viruses in humans and the continuous emergence of new henipaviruses as well as henipa-like viruses, it is necessary to conduct a more comprehensive investigation of the biology of henipaviruses and their interaction with the host. The replication of henipaviruses and the development of antiviral agents can be studied in systems that allow experiments to be performed under biosafety level 2 conditions. Here, we developed robust minigenome systems for the Nipah virus (NiV) and Hendra virus (HeV) that provide a convenient alternative for studying NiV and HeV replication. Using these systems, we demonstrate that any combination of the three polymerase complex proteins of NiV and HeV could effectively initiate the replication of both viral minigenomes, which suggests that the interaction regions of the polymerase complex proteins could be effective targets for universal and effective anti-henipavirus interventions.
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Affiliation(s)
- Xiao Li
- Department of Molecular Microbiology and Center for Women's Infectious Diseases Research, Washington University in St Louis, St. Louis, Missouri, USA
| | - Yanling Yang
- Department of Molecular Microbiology and Center for Women's Infectious Diseases Research, Washington University in St Louis, St. Louis, Missouri, USA
| | - Carolina B López
- Department of Molecular Microbiology and Center for Women's Infectious Diseases Research, Washington University in St Louis, St. Louis, Missouri, USA
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Bodmer BS, Hoenen T, Wendt L. Molecular insights into the Ebola virus life cycle. Nat Microbiol 2024:10.1038/s41564-024-01703-z. [PMID: 38783022 DOI: 10.1038/s41564-024-01703-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [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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3
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Xie SZ, Yao K, Li B, Peng C, Yang XL, Shi ZL. Development of a Měnglà virus minigenome and comparison of its polymerase complexes those of other filoviruses. Virol Sin 2024:S1995-820X(24)00074-9. [PMID: 38782261 DOI: 10.1016/j.virs.2024.03.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 03/25/2024] [Indexed: 05/25/2024] Open
Abstract
Ebola virus (EBOV) and Marburg virus (MARV), members of the Filoviridae family, are highly pathogenic and can cause hemorrhagic fevers, significantly impacting human society. Bats are considered reservoirs of these viruses because related filoviruses have been discovered in bats. However, due to requirement for maximum containment laboratories when studying infectious virus, the characterization of bat filoviruses often relies on pseudoviruses and minigenome systems. In this study, we used RACE technology to sequence the 3'-leader and 5'-trailer of MLAV and constructed a minigenome. Similar to MARV, the transcription activities of the MLAV minigenome are independent of VP30. We further assessed the effects of polymorphisms at the 5' end on MLAV minigenome activity and identified certain mutations that decrease minigenome reporter efficiency, probably due to alterations in the RNA secondary structure. The reporter activity upon recombination of the 3'-leaders and 5'-trailers of MLAV, MARV, and EBOV with those of the homologous or heterologous minigenomes was compared and it was found that the polymerase complex and leader and trailer sequences exhibit intrinsic specificities. Additionally, we investigated whether the polymerase complex proteins from EBOV and MARV support MLAV minigenome RNA synthesis and found that the homologous system is more efficient than the heterologous system. Remdesivir efficiently inhibited MLAV as well as EBOV replication. In summary, this study provided new information about bat filoviruses and the minigenome will be a useful tool for high-throughput antiviral drug screening.
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Affiliation(s)
- Shi-Zhe Xie
- State Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ke Yao
- State Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Bei Li
- State Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Cheng Peng
- State Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Xing-Lou Yang
- Yunnan Key Laboratory of Biodiversity Information, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650201, China; Hubei Jiangxia Laboratory, Wuhan, 430200, China.
| | - Zheng-Li Shi
- State Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China.
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4
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Lyu Y, Li W, Guo Q, Wu H. Mapping knowledge landscapes and emerging trends of Marburg virus: A text-mining study. Heliyon 2024; 10:e29691. [PMID: 38655363 PMCID: PMC11036101 DOI: 10.1016/j.heliyon.2024.e29691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 04/11/2024] [Accepted: 04/12/2024] [Indexed: 04/26/2024] Open
Abstract
Background Marburg virus (MARV), a close relative of Ebola virus, could induce hemorrhagic fevers in humans with high mortality rate. In recent years, increasing attention has been paid to this highly lethal virus due to sporadic outbreaks observed in various African nations. This bibliometric analysis endeavors to elucidate the trends, dynamics, and focal points of knowledge that have delineated the landscape of research concerning MARV. Methods Relevant literature on MARV from 1968 to 2023 was extracted from the Web of Science Core Collection database. Following this, the data underwent bibliometric analysis and visualization procedures utilizing online analysis platform, CiteSpace 6.2R6, and VOSviewer 1.6.20. Three different types of bibliometric indicators including quantitative indicator, qualitative indicators, and structural indicators were used to gauge a researcher's productivity, assess the quality of their work, and analyze publication relationships, respectively. Results MARV is mainly prevalent in Africa. And approximately 643 confirmed cases have been described in the literature to date, and mortality observed was 81.2 % in overall patients. A total of 1014 papers comprising 869 articles and 145 reviews were included. The annual publications showed an increasing growth pattern from 1968 to 2023 (R2 = 0.8838). The United States stands at the forefront of this discipline, having dedicated substantial financial and human resources to scientific inquiry. However, co-authorship analysis showed the international research collaboration needs to be further strengthened. Based on reference and keywords analysis, contemporary MARV research encompasses pivotal areas: primarily, prioritizing the creation of prophylactic vaccines to impede viral spread, and secondarily, exploring targeted antiviral strategies, including small-molecule antivirals or MARV-specific monoclonal antibodies. Additionally, a comprehensive grasp of viral transmission, transcription, and replication mechanisms remains a central focus in ongoing investigations. And future MARV studies are expected to focus on evaluating clinical trial safety and efficacy, developing inhibitors to contain viral spread, exploring vaccine immunogenicity, virus-host association studies, and elucidating the role of neutralizing antibodies in MARV treatment. Conclusion The present study offered comprehensive insights into the contemporary status and trajectories of MARV over the past decades. This enables researchers to discern novel collaborative prospects, institutional partnerships, emerging topics, and research forefronts within this domain.
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Affiliation(s)
- Yuanjun Lyu
- Department of Geriatric Respiratory and Sleep, The First Affiliated Hospital of Zhengzhou University Zhengzhou 450052, Henan, China
| | - Wanqing Li
- Department of Operating Room, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, China
| | - Qiang Guo
- Department of Orthopaedics, Baodi Clinical College of Tianjin Medical University, Tianjin, China
| | - Haiyang Wu
- Department of Orthopaedics, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
- Department of Clinical College of Neurology, Neurosurgery and Neurorehabilitation, Tianjin Medical University, Tianjin, China
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Rodríguez-Salazar CA, van Tol S, Mailhot O, Gonzalez-Orozco M, Galdino GT, Warren AN, Teruel N, Behera P, Afreen KS, Zhang L, Juelich TL, Smith JK, Zylber MI, Freiberg AN, Najmanovich RJ, Giraldo MI, Rajsbaum R. Ebola virus VP35 interacts non-covalently with ubiquitin chains to promote viral replication. PLoS Biol 2024; 22:e3002544. [PMID: 38422166 PMCID: PMC10942258 DOI: 10.1371/journal.pbio.3002544] [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: 01/23/2024] [Revised: 03/15/2024] [Accepted: 02/09/2024] [Indexed: 03/02/2024] Open
Abstract
Ebolavirus (EBOV) belongs to a family of highly pathogenic viruses that cause severe hemorrhagic fever in humans. EBOV replication requires the activity of the viral polymerase complex, which includes the cofactor and Interferon antagonist VP35. We previously showed that the covalent ubiquitination of VP35 promotes virus replication by regulating interactions with the polymerase complex. In addition, VP35 can also interact non-covalently with ubiquitin (Ub); however, the function of this interaction is unknown. Here, we report that VP35 interacts with free (unanchored) K63-linked polyUb chains. Ectopic expression of Isopeptidase T (USP5), which is known to degrade unanchored polyUb chains, reduced VP35 association with Ub and correlated with diminished polymerase activity in a minigenome assay. Using computational methods, we modeled the VP35-Ub non-covalent interacting complex, identified the VP35-Ub interacting surface, and tested mutations to validate the interface. Docking simulations identified chemical compounds that can block VP35-Ub interactions leading to reduced viral polymerase activity. Treatment with the compounds reduced replication of infectious EBOV in cells and in vivo in a mouse model. In conclusion, we identified a novel role of unanchored polyUb in regulating Ebola virus polymerase function and discovered compounds that have promising anti-Ebola virus activity.
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Affiliation(s)
- Carlos A. Rodríguez-Salazar
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Molecular Biology and Virology Laboratory, Faculty of Medicine and Health Sciences, Corporación Universitaria Empresarial Alexander von Humboldt, Armenia, Colombia
| | - Sarah van Tol
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Olivier Mailhot
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, Canada
| | - Maria Gonzalez-Orozco
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Gabriel T. Galdino
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, Canada
| | - Abbey N. Warren
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Center for Virus-Host-Innate Immunity and Department of Medicine; Rutgers Biomedical and Health Sciences, Institute for Infectious and Inflammatory Diseases, Rutgers University, Newark, New Jersey, United States of America
| | - Natalia Teruel
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, Canada
| | - 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, New Jersey, United States of America
| | - 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, New Jersey, United States of America
| | - Lihong Zhang
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Terry L. Juelich
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Jennifer K. Smith
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - María Inés Zylber
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, Canada
| | - Alexander N. Freiberg
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Rafael J. Najmanovich
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, Canada
| | - Maria I. Giraldo
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Ricardo Rajsbaum
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Center for Virus-Host-Innate Immunity and Department of Medicine; Rutgers Biomedical and Health Sciences, Institute for Infectious and Inflammatory Diseases, Rutgers University, Newark, New Jersey, United States of America
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6
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Corda PO, Bollen M, Ribeiro D, Fardilha M. Emerging roles of the Protein Phosphatase 1 (PP1) in the context of viral infections. Cell Commun Signal 2024; 22:65. [PMID: 38267954 PMCID: PMC10807198 DOI: 10.1186/s12964-023-01468-8] [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: 10/16/2023] [Accepted: 12/30/2023] [Indexed: 01/26/2024] Open
Abstract
Protein Phosphatase 1 (PP1) is a major serine/threonine phosphatase in eukaryotes, participating in several cellular processes and metabolic pathways. Due to their low substrate specificity, PP1's catalytic subunits do not exist as free entities but instead bind to Regulatory Interactors of Protein Phosphatase One (RIPPO), which regulate PP1's substrate specificity and subcellular localization. Most RIPPOs bind to PP1 through combinations of short linear motifs (4-12 residues), forming highly specific PP1 holoenzymes. These PP1-binding motifs may, hence, represent attractive targets for the development of specific drugs that interfere with a subset of PP1 holoenzymes. Several viruses exploit the host cell protein (de)phosphorylation machinery to ensure efficient virus particle formation and propagation. While the role of many host cell kinases in viral life cycles has been extensively studied, the targeting of phosphatases by viral proteins has been studied in less detail. Here, we compile and review what is known concerning the role of PP1 in the context of viral infections and discuss how it may constitute a putative host-based target for the development of novel antiviral strategies.
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Affiliation(s)
- Pedro O Corda
- Institute of Biomedicine (iBiMED), Department of Medical Sciences, University of Aveiro, Aveiro, Portugal
| | - Mathieu Bollen
- Department of Cellular and Molecular Medicine, Laboratory of Biosignaling & Therapeutics, Katholieke Universiteit Leuven, Louvain, Belgium
| | - Daniela Ribeiro
- Institute of Biomedicine (iBiMED), Department of Medical Sciences, University of Aveiro, Aveiro, Portugal.
| | - Margarida Fardilha
- Institute of Biomedicine (iBiMED), Department of Medical Sciences, University of Aveiro, Aveiro, Portugal.
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7
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Bodmer BS, Hoenen T. Reverse Genetics Systems for Filoviruses. Methods Mol Biol 2024; 2733:1-14. [PMID: 38064023 DOI: 10.1007/978-1-0716-3533-9_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
Filoviruses are causative agents of severe hemorrhagic fevers with high case fatality rates in humans. For studies of virus biology and the subsequent development of countermeasures, reverse genetic systems, and especially those facilitating the generation of recombinant filoviruses, are indispensable. Here, we describe the generation of recombinant filoviruses from cDNA.
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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.
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Chen YK, Gahtani RM, Al Shahrani M, Hani U, Alshabrmi FM, Alam S, Almohaimeed HM, Basabrain AA, Shahab M, Xie MZ. Identification of potential inhibitors targeting Ebola virus VP35 protein: a computational strategy. J Biomol Struct Dyn 2023:1-13. [PMID: 38124513 DOI: 10.1080/07391102.2023.2294384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 12/04/2023] [Indexed: 12/23/2023]
Abstract
Ebola virus (EBOV) poses a severe threat as a highly infectious pathogen, causing devastating hemorrhagic fever in both humans and animals. The EBOV virus VP35 protein plays a crucial role in viral replication and exhibits the ability to suppress the host interferon cascade, leading to immune system depletion. As a potential drug target, VP35 protein inhibition holds promise for combating EBOV. To discover new drug candidates, we employed a computer-aided drug design approach, focusing on compounds capable of inhibiting VP35 protein replication. In this connection, a pharmacophore model was generated using molecular interactions between the VP35 protein and its inhibitor. ZINC and Cambridge database were screened using validated pharmacophore model. Further the compounds were filtered based on Lipinski's rule of five and subjected to MD simulation and relative binding free energy calculation. Six compounds manifest a significant docking score and strong binding interaction towards VP35 protein. MD simulations further confirmed the remarkable stability of these six complexes. Relative binding free energy calculations also showed significant ΔG value in the range of -132.3 and -49.3 kcal/mol. This study paves the way for further optimization of these compounds as potential inhibitors of VP35, facilitating subsequent experimental in vitro studies.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Yan-Kun Chen
- School of Chinese Medicine, Hunan University of Chinese Medicine, Changsha, China
- Precision Medicine R&D Center, Zhuhai Institute of Advanced Technology, Zhuhai, China
| | - Reem M Gahtani
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Khalid University, Abha, Saudi Arabia
| | - Mesfer Al Shahrani
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Khalid University, Abha, Saudi Arabia
| | - Umme Hani
- Department of Pharmaceutics, College of Pharmacy, King Khalid University, Abha,Saudia Arabia
| | - Fahad M Alshabrmi
- Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Saudi Arabia
| | - Sarfaraz Alam
- Tunneling Group, Biotechnology Centre, Silesian University of Technology, Gliwice, Poland
| | - Hailah M Almohaimeed
- Department of Basic Science, College of Medicine, Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia
| | - Ammar A Basabrain
- Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
- Hematology Research Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Muhammad Shahab
- State Key Laboratories of Chemical Resources Engineering, Beijing University of Chemical Technology, Beijing, China
| | - Meng-Zhou Xie
- School of Chinese Medicine, Hunan University of Chinese Medicine, Changsha, China
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9
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Bodmer BS, Breithaupt A, Heung M, Brunetti JE, Henkel C, Müller-Guhl J, Rodríguez E, Wendt L, Winter SL, Vallbracht M, Müller A, Römer S, Chlanda P, Muñoz-Fontela C, Hoenen T, Escudero-Pérez B. In vivo characterization of the novel ebolavirus Bombali virus suggests a low pathogenic potential for humans. Emerg Microbes Infect 2023; 12:2164216. [PMID: 36580440 PMCID: PMC9858441 DOI: 10.1080/22221751.2022.2164216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Ebolaviruses cause outbreaks of haemorrhagic fever in Central and West Africa. Some members of this genus such as Ebola virus (EBOV) are highly pathogenic, with case fatality rates of up to 90%, whereas others such as Reston virus (RESTV) are apathogenic for humans. Bombali virus (BOMV) is a novel ebolavirus for which complete genome sequences were recently found in free-tailed bats, although no infectious virus could be isolated. Its pathogenic potential for humans is unknown. To address this question, we first determined whether proteins encoded by the available BOMV sequence found in Chaerephon pumilus were functional in in vitro assays. The correction of an apparent sequencing error in the glycoprotein based on these data then allowed us to generate infectious BOMV using reverse genetics and characterize its infection of human cells. Furthermore, we used HLA-A2-transgenic, NOD-scid-IL-2γ receptor-knockout (NSG-A2) mice reconstituted with human haematopoiesis as a model to evaluate the pathogenicity of BOMV in vivo in a human-like immune environment. These data demonstrate that not only does BOMV show a slower growth rate than EBOV in vitro, but it also shows low pathogenicity in humanized mice, comparable to previous studies using RESTV. Taken together, these findings suggest a low pathogenic potential of BOMV for humans.
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Affiliation(s)
- B. S. Bodmer
- Institute for Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald – Insel Riems, Germany
| | - A. Breithaupt
- Department of Experimental Animal Facilities and Biorisk Management, Friedrich-Loeffler-Institut, Greifswald – Insel Riems, Germany
| | - M. Heung
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - J. E. Brunetti
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - C. Henkel
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - J. Müller-Guhl
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany,Leibniz Institute of Virology, Hamburg, Germany
| | - E. Rodríguez
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany,German Center for Infection Research (DZIF), Partner Site Hamburg-Luebeck-Borstel, Braunschweig, Germany
| | - L. Wendt
- Institute for Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald – Insel Riems, Germany
| | - S. L. Winter
- Schaller Research Groups, Department of Infectious Diseases, Virology, Heidelberg University Hospital, Heidelberg, Germany
| | - M. Vallbracht
- Schaller Research Groups, Department of Infectious Diseases, Virology, Heidelberg University Hospital, Heidelberg, Germany
| | - A. Müller
- Institute for Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald – Insel Riems, Germany
| | - S. Römer
- Institute for Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald – Insel Riems, Germany
| | - P. Chlanda
- Schaller Research Groups, Department of Infectious Diseases, Virology, Heidelberg University Hospital, Heidelberg, Germany
| | - C. Muñoz-Fontela
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany,German Center for Infection Research (DZIF), Partner Site Hamburg-Luebeck-Borstel, Braunschweig, Germany
| | - T. Hoenen
- Institute for Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald – Insel Riems, Germany, T. Hoenen Institute for Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Südufer 10, Greifswald – Insel Riems, 17493Germany
| | - B. Escudero-Pérez
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany,German Center for Infection Research (DZIF), Partner Site Hamburg-Luebeck-Borstel, Braunschweig, Germany
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10
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Debroy B, Chowdhury S, Pal K. Designing a novel and combinatorial multi-antigenic epitope-based vaccine "MarVax" against Marburg virus-a reverse vaccinology and immunoinformatics approach. J Genet Eng Biotechnol 2023; 21:143. [PMID: 38012426 PMCID: PMC10681968 DOI: 10.1186/s43141-023-00575-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Accepted: 10/26/2023] [Indexed: 11/29/2023]
Abstract
CONTEXT Marburg virus (MARV) is a member of the Filoviridae family and causes Marburg virus disease (MVD) among humans and primates. With fatality rates going up to 88%, there is currently no commercialized cure or vaccine to combat the infection. The National Institute of Allergy and Infectious Diseases (NIAID) classified MARV as priority pathogen A, which presages the need for a vaccine candidate which can provide stable, long-term adaptive immunity. The surface glycoprotein (GP) and fusion protein (FP) mediate the adherence, fusion, and entry of the virus into the host cell via the TIM-I receptor. Being important antigenic determinants, studies reveal that GP and FP are prone to evolutionary mutations, underscoring the requirement of a vaccine construct capable of eliciting a robust and sustained immune response. In this computational study, a reverse vaccinology approach was employed to design a combinatorial vaccine from conserved and antigenic epitopes of essential viral proteins of MARV, namely GP, VP24, VP30, VP35, and VP40 along with an endogenous protein large polymerase (L). METHODS Epitopes for T-cell and B-cell were predicted using TepiTool and ElliPro, respectively. The surface-exposed TLRs like TLR2, TLR4, and TLR5 were used to screen high-binding affinity epitopes using the protein-peptide docking platform MdockPeP. The best binding epitopes were selected and assembled with linkers to design a recombinant multi-epitope vaccine construct which was then modeled in Robetta. The in silico biophysical and biochemical analyses of the recombinant vaccine were performed. The docking and MD simulation of the vaccine using WebGro and CABS-Flex against TLRs support the stable binding of vaccine candidates. A virtual immune simulation to check the immediate and long-term immunogenicity was carried out using the C-ImmSim server. RESULTS The biochemical characteristics and docking studies with MD simulation establish the recombinant protein vaccine construct MarVax as a stable, antigenic, and potent vaccine molecule. Immune simulation studies reveal 1-year passive immunity which needs to be validated by in vivo studies.
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Affiliation(s)
- Bishal Debroy
- Department of Biological Sciences, School of Life Science and Biotechnology, Adamas University, Barasat-Barrackpore Road, Kolkata, West Bengal, 700126, India
| | - Sribas Chowdhury
- Department of Biotechnology, School of Life Science and Biotechnology, Adamas University, Barasat-Barrackpore Road, Kolkata, West Bengal, 700126, India
| | - Kuntal Pal
- Cancer Biology Laboratory, Adamas University, Barasat-Barrackpore Road, Kolkata, West Bengal, 700126, India.
- School of Biosciences and Technology (SBST), Vellore Institute of Technology, Vellore, Tamil Nadu, 632014, India.
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11
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Hsu CJ, Chen CH, Chen WT, Liu PC, Chang TY, Lin MH, Chen CC, Chen HY, Huang CH, Cheng YH, Sun JR. Development of an EBOV MiniG plus system as an advanced tool for anti-Ebola virus drug screening. Heliyon 2023; 9:e22138. [PMID: 38045158 PMCID: PMC10692823 DOI: 10.1016/j.heliyon.2023.e22138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 10/21/2023] [Accepted: 11/05/2023] [Indexed: 12/05/2023] Open
Abstract
The incidence of zoonotic diseases, such as coronavirus disease 2019 and Ebola virus disease, is increasing worldwide. However, drug and vaccine development for zoonotic diseases has been hampered because the experiments involving live viruses are limited to high-containment laboratories. The Ebola virus minigenome system enables researchers to study the Ebola virus under BSL-2 conditions. Here, we found that the addition of the nucleocapsid protein of human coronaviruses, such as severe acute respiratory syndrome coronavirus 2, can increase the ratio of green fluorescent protein-positive cells by 1.5-2 folds in the Ebola virus minigenome system. Further analysis showed that the nucleocapsid protein acts as an activator of the Ebola virus minigenome system. Here, we developed an EBOV MiniG Plus system based on the Ebola virus minigenome system by adding the SARS-CoV-2 nucleocapsid protein. By evaluating the antiviral effect of remdesivir and rupintrivir, we demonstrated that compared to that of the traditional Ebola virus minigenome system, significant concentration-dependent activity was observed in the EBOV MiniG Plus system. Taken together, these results demonstrate the utility of adding nucleocapsid protein to the Ebola virus minigenome system to create a powerful platform for screening antiviral drugs against the Ebola virus.
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Affiliation(s)
- Chi-Ju Hsu
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
- Graduate Institute of Medical Science, National Defense Medical Center, Taipei, Taiwan
| | - Cheng-Hsiu Chen
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
- Graduate Institute of Medical Science, National Defense Medical Center, Taipei, Taiwan
| | - Wen-Ting Chen
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
| | - Ping-Cheng Liu
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
- Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taiwan
| | - Tein-Yao Chang
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
- Department of Pathology and Graduate Institute of Pathology and Parasitology, Tri-Service General Hospital, National Defense Medical Center, Taiwan
| | - Meng-He Lin
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
| | - Cheng-Cheung Chen
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
- Graduate Institute of Medical Science, National Defense Medical Center, Taipei, Taiwan
| | - Hsing-Yu Chen
- Department of Medical Techniques, Taipei City Hospital Ren-Ai Branch, Taiwan
| | - Chih-Heng Huang
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
- Graduate Institute of Medical Science, National Defense Medical Center, Taipei, Taiwan
| | - Yun-Hsiang Cheng
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
- Department of Physiology and Biophysics, Graduate Institute of Physiology, National Defense Medical Center, Taiwan
| | - Jun-Ren Sun
- Institute of Preventive Medicine, National Defense Medical Center, Taipei, Taiwan
- Graduate Institute of Medical Science, National Defense Medical Center, Taipei, Taiwan
- Department of Physiology and Biophysics, Graduate Institute of Physiology, National Defense Medical Center, Taiwan
- Division of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taiwan
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12
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Srivastava S, Sharma D, Kumar S, Sharma A, Rijal R, Asija A, Adhikari S, Rustagi S, Sah S, Al-qaim ZH, Bashyal P, Mohanty A, Barboza JJ, Rodriguez-Morales AJ, Sah R. Emergence of Marburg virus: a global perspective on fatal outbreaks and clinical challenges. Front Microbiol 2023; 14:1239079. [PMID: 37771708 PMCID: PMC10526840 DOI: 10.3389/fmicb.2023.1239079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 08/25/2023] [Indexed: 09/30/2023] Open
Abstract
The Marburg virus (MV), identified in 1967, has caused deadly outbreaks worldwide, the mortality rate of Marburg virus disease (MVD) varies depending on the outbreak and virus strain, but the average case fatality rate is around 50%. However, case fatality rates have varied from 24 to 88% in past outbreaks depending on virus strain and case management. Designated a priority pathogen by the National Institute of Allergy and Infectious Diseases (NIAID), MV induces hemorrhagic fever, organ failure, and coagulation issues in both humans and non-human primates. This review presents an extensive exploration of MVD outbreak evolution, virus structure, and genome, as well as the sources and transmission routes of MV, including human-to-human spread and involvement of natural hosts such as the Egyptian fruit bat (Rousettus aegyptiacus) and other Chiroptera species. The disease progression involves early viral replication impacting immune cells like monocytes, macrophages, and dendritic cells, followed by damage to the spleen, liver, and secondary lymphoid organs. Subsequent spread occurs to hepatocytes, endothelial cells, fibroblasts, and epithelial cells. MV can evade host immune response by inhibiting interferon type I (IFN-1) synthesis. This comprehensive investigation aims to enhance understanding of pathophysiology, cellular tropism, and injury sites in the host, aiding insights into MVD causes. Clinical data and treatments are discussed, albeit current methods to halt MVD outbreaks remain elusive. By elucidating MV infection's history and mechanisms, this review seeks to advance MV disease treatment, drug development, and vaccine creation. The World Health Organization (WHO) considers MV a high-concern filovirus causing severe and fatal hemorrhagic fever, with a death rate ranging from 24 to 88%. The virus often spreads through contact with infected individuals, originating from animals. Visitors to bat habitats like caves or mines face higher risk. We tailored this search strategy for four databases: Scopus, Web of Science, Google Scholar, and PubMed. we primarily utilized search terms such as "Marburg virus," "Epidemiology," "Vaccine," "Outbreak," and "Transmission." To enhance comprehension of the virus and associated disease, this summary offers a comprehensive overview of MV outbreaks, pathophysiology, and management strategies. Continued research and learning hold promise for preventing and controlling future MVD outbreaks. GRAPHICAL ABSTRACT.
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Affiliation(s)
- Shriyansh Srivastava
- Department of Pharmacology, Delhi Pharmaceutical Sciences and Research University (DPSRU), New Delhi, India
- Department of Pharmacy, School of Medical and Allied Sciences, Galgotias University, Greater Noida, India
| | - Deepika Sharma
- Department of Pharmacy, School of Medical and Allied Sciences, Galgotias University, Greater Noida, India
| | - Sachin Kumar
- Department of Pharmacology, Delhi Pharmaceutical Sciences and Research University (DPSRU), New Delhi, India
| | - Aditya Sharma
- Department of Pharmacy, School of Medical and Allied Sciences, Galgotias University, Greater Noida, India
| | - Rishikesh Rijal
- Division of Infectious Diseases, University of Louisville, Louisville, KY, United States
| | - Ankush Asija
- WVU United Hospital Center, Bridgeport, WV, United States
| | | | - Sarvesh Rustagi
- School of Applied and Life Sciences, Uttaranchal University, Dehradun, Uttarakhand, India
| | - Sanjit Sah
- Global Consortium for Public Health and Research, Datta Meghe Institute of Higher Education and Research, Jawaharlal Nehru Medical College, Wardha, India
- Department of Anesthesia Techniques, SR Sanjeevani Hospital, Siraha, Nepal
| | | | - Prashant Bashyal
- Lumbini Medical College and Teaching Hospital, Kathmandu University Parvas, Palpa, Nepal
| | - Aroop Mohanty
- Department of Clinical Microbiology, All India Institute of Medical Sciences, Gorakhpur, Uttar Pradesh, India
| | | | - Alfonso J. Rodriguez-Morales
- Master Program on Clinical Epidemiology and Biostatistics, Universidad Científica del Sur, Lima, Peru
- Gilbert and Rose-Marie Chagoury School of Medicine, Lebanese American University, Beirut, Lebanon
| | - Ranjit Sah
- Department of Microbiology, Tribhuvan University Teaching Spital, Institute of Medicine, Kathmandu, Nepal
- Department of Microbiology, Dr. D. Y. Patil Medical College, Hospital and Research Centre, Dr. D. Y. Patil Vidyapeeth, Pune, Maharashtra, India
- Department of Public Health Dentistry, Dr. D. Y. Patil Dental College and Hospital, Dr. D. Y. Patil Vidyapeeth, Pune, Maharashtra, India
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13
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Werner AD, Schauflinger M, Norris MJ, Klüver M, Trodler A, Herwig A, Brandstädter C, Dillenberger M, Klebe G, Heine A, Saphire EO, Becker K, Becker S. The C-terminus of Sudan ebolavirus VP40 contains a functionally important CX nC motif, a target for redox modifications. Structure 2023; 31:1038-1051.e7. [PMID: 37392738 DOI: 10.1016/j.str.2023.06.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 05/10/2023] [Accepted: 06/06/2023] [Indexed: 07/03/2023]
Abstract
The Ebola virus matrix protein VP40 mediates viral budding and negatively regulates viral RNA synthesis. The mechanisms by which these two functions are exerted and regulated are unknown. Using a high-resolution crystal structure of Sudan ebolavirus (SUDV) VP40, we show here that two cysteines in the flexible C-terminal arm of VP40 form a stabilizing disulfide bridge. Notably, the two cysteines are targets of posttranslational redox modifications and interact directly with the host`s thioredoxin system. Mutation of the cysteines impaired the budding function of VP40 and relaxed its inhibitory role for viral RNA synthesis. In line with these results, the growth of recombinant Ebola viruses carrying cysteine mutations was impaired and the released viral particles were elongated. Our results revealed the exact positions of the cysteines in the C-terminal arm of SUDV VP40. The cysteines and/or their redox status are critically involved in the differential regulation of viral budding and viral RNA synthesis.
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Affiliation(s)
| | | | - Michael J Norris
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Michael Klüver
- Institute for Virology, Philipps-University of Marburg, Marburg, Germany
| | - Anna Trodler
- Institute for Virology, Philipps-University of Marburg, Marburg, Germany
| | - Astrid Herwig
- Institute for Virology, Philipps-University of Marburg, Marburg, Germany
| | - Christina Brandstädter
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University Giessen, Giessen, Germany
| | - Melissa Dillenberger
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University Giessen, Giessen, Germany
| | - Gerhard Klebe
- Institute for Pharmaceutical Chemistry, Philipps-University of Marburg, Marburg, Germany
| | - Andreas Heine
- Institute for Pharmaceutical Chemistry, Philipps-University of Marburg, Marburg, Germany
| | | | - Katja Becker
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University Giessen, Giessen, Germany
| | - Stephan Becker
- Institute for Virology, Philipps-University of Marburg, Marburg, Germany.
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14
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Rodríguez-Salazar CA, van Tol S, Mailhot O, Galdino G, Teruel N, Zhang L, Warren AN, González-Orozco M, Freiberg AN, Najmanovich RJ, Giraldo MI, Rajsbaum R. Ebola Virus VP35 Interacts Non-Covalently with Ubiquitin Chains to Promote Viral Replication Creating New Therapeutic Opportunities. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.14.549057. [PMID: 37503276 PMCID: PMC10369991 DOI: 10.1101/2023.07.14.549057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Ebolavirus (EBOV) belongs to a family of highly pathogenic viruses that cause severe hemorrhagic fever in humans. EBOV replication requires the activity of the viral polymerase complex, which includes the co-factor and Interferon antagonist VP35. We previously showed that the covalent ubiquitination of VP35 promotes virus replication by regulating interactions with the polymerase complex. In addition, VP35 can also interact non-covalently with ubiquitin (Ub); however, the function of this interaction is unknown. Here, we report that VP35 interacts with free (unanchored) K63-linked polyUb chains. Ectopic expression of Isopeptidase T (USP5), which is known to degrade unanchored polyUb chains, reduced VP35 association with Ub and correlated with diminished polymerase activity in a minigenome assay. Using computational methods, we modeled the VP35-Ub non-covalent interacting complex, identified the VP35-Ub interacting surface and tested mutations to validate the interface. Docking simulations identified chemical compounds that can block VP35-Ub interactions leading to reduced viral polymerase activity that correlated with reduced replication of infectious EBOV. In conclusion, we identified a novel role of unanchored polyUb in regulating Ebola virus polymerase function and discovered compounds that have promising anti-Ebola virus activity.
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Affiliation(s)
- Carlos A. Rodríguez-Salazar
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston 77555, Texas, USA
- Molecular Biology and Virology Laboratory, Faculty of Medicine and Health Sciences, Corporación Universitaria Empresarial Alexander von Humboldt, Armenia 630003, Colombia
| | - Sarah van Tol
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston 77555, Texas, USA
| | - Olivier Mailhot
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, Canada
| | - Gabriel Galdino
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, Canada
| | - Natalia Teruel
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, Canada
| | - Lihong Zhang
- Department of Pathology, University of Texas Medical Branch, Galveston 77555, Texas, USA
| | - Abbey N. Warren
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston 77555, Texas, USA
- Center for Virus-Host-Innate Immunity and Department of Medicine; Rutgers Biomedical and Health Sciences, Institute for Infectious and Inflammatory Diseases, Rutgers University, Newark, New Jersey 07103
| | - María González-Orozco
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston 77555, Texas, USA
| | - Alexander N. Freiberg
- Department of Pathology, University of Texas Medical Branch, Galveston 77555, Texas, USA
| | - Rafael J. Najmanovich
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, Canada
| | - María I. Giraldo
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston 77555, Texas, USA
| | - Ricardo Rajsbaum
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston 77555, Texas, USA
- Center for Virus-Host-Innate Immunity and Department of Medicine; Rutgers Biomedical and Health Sciences, Institute for Infectious and Inflammatory Diseases, Rutgers University, Newark, New Jersey 07103
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15
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Fang J, Castillon G, Phan S, McArdle S, Hariharan C, Adams A, Ellisman MH, Deniz AA, Saphire EO. Spatial and functional arrangement of Ebola virus polymerase inside phase-separated viral factories. Nat Commun 2023; 14:4159. [PMID: 37443171 PMCID: PMC10345124 DOI: 10.1038/s41467-023-39821-7] [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: 12/21/2022] [Accepted: 06/29/2023] [Indexed: 07/15/2023] Open
Abstract
Ebola virus (EBOV) infection induces the formation of membrane-less, cytoplasmic compartments termed viral factories, in which multiple viral proteins gather and coordinate viral transcription, replication, and assembly. Key to viral factory function is the recruitment of EBOV polymerase, a multifunctional machine that mediates transcription and replication of the viral RNA genome. We show that intracellularly reconstituted EBOV viral factories are biomolecular condensates, with composition-dependent internal exchange dynamics that likely facilitates viral replication. Within the viral factory, we found the EBOV polymerase clusters into foci. The distance between these foci increases when viral replication is enabled. In addition to the typical droplet-like viral factories, we report the formation of network-like viral factories during EBOV infection. Unlike droplet-like viral factories, network-like factories are inactive for EBOV nucleocapsid assembly. This unique view of EBOV propagation suggests a form-to-function relationship that describes how physical properties and internal structures of biomolecular condensates influence viral biogenesis.
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Affiliation(s)
- Jingru Fang
- La Jolla Institute for Immunology, La Jolla, CA, USA
- Scripps Research, La Jolla, CA, USA
| | - Guillaume Castillon
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, Department of Neurosciences, University of California San Diego, School of Medicine, La Jolla, CA, USA
| | - Sebastien Phan
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, Department of Neurosciences, University of California San Diego, School of Medicine, La Jolla, CA, USA
| | - Sara McArdle
- La Jolla Institute for Immunology, La Jolla, CA, USA
| | | | - Aiyana Adams
- La Jolla Institute for Immunology, La Jolla, CA, USA
| | - Mark H Ellisman
- National Center for Microscopy and Imaging Research, Center for Research in Biological Systems, Department of Neurosciences, University of California San Diego, School of Medicine, La Jolla, CA, USA
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16
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Hu S, Fujita-Fujiharu Y, Sugita Y, Wendt L, Muramoto Y, Nakano M, Hoenen T, Noda T. Cryoelectron microscopic structure of the nucleoprotein-RNA complex of the European filovirus, Lloviu virus. PNAS NEXUS 2023; 2:pgad120. [PMID: 37124400 PMCID: PMC10139700 DOI: 10.1093/pnasnexus/pgad120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 03/17/2023] [Accepted: 03/27/2023] [Indexed: 05/02/2023]
Abstract
Lloviu virus (LLOV) is a novel filovirus detected in Schreiber's bats in Europe. The isolation of the infectious LLOV from bats has raised public health concerns. However, the virological and molecular characteristics of LLOV remain largely unknown. The nucleoprotein (NP) of LLOV encapsidates the viral genomic RNA to form a helical NP-RNA complex, which acts as a scaffold for nucleocapsid formation and de novo viral RNA synthesis. In this study, using single-particle cryoelectron microscopy, we determined two structures of the LLOV NP-RNA helical complex, comprising a full-length and a C-terminally truncated NP. The two helical structures were identical, demonstrating that the N-terminal region determines the helical arrangement of the NP. The LLOV NP-RNA protomers displayed a structure similar to that in the Ebola and Marburg virus, but the spatial arrangements in the helix differed. Structure-based mutational analysis identified amino acids involved in the helical assembly and viral RNA synthesis. These structures advance our understanding of the filovirus nucleocapsid formation and provide a structural basis for the development of antifiloviral therapeutics.
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Affiliation(s)
- Shangfan Hu
- Laboratory of Ultrastructural Virology, Institute for Life and Medical Sciences, Kyoto University, 53 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan
- Laboratory of Ultrastructural Virology, Graduate School of Biostudies, Kyoto University, 53 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan
- CREST, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Yoko Fujita-Fujiharu
- Laboratory of Ultrastructural Virology, Institute for Life and Medical Sciences, Kyoto University, 53 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan
- Laboratory of Ultrastructural Virology, Graduate School of Biostudies, Kyoto University, 53 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan
- CREST, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Yukihiko Sugita
- Laboratory of Ultrastructural Virology, Institute for Life and Medical Sciences, Kyoto University, 53 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan
- Laboratory of Ultrastructural Virology, Graduate School of Biostudies, Kyoto University, 53 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan
- Hakubi Center for Advanced Research, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
| | - Lisa Wendt
- Laboratory for Integrative Cell and Infection Biology, Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Insel Riems, Greifswald 17493, Germany
| | - Yukiko Muramoto
- Laboratory of Ultrastructural Virology, Institute for Life and Medical Sciences, Kyoto University, 53 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan
- Laboratory of Ultrastructural Virology, Graduate School of Biostudies, Kyoto University, 53 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan
- CREST, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Masahiro Nakano
- Laboratory of Ultrastructural Virology, Institute for Life and Medical Sciences, Kyoto University, 53 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan
- Laboratory of Ultrastructural Virology, Graduate School of Biostudies, Kyoto University, 53 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan
- CREST, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Thomas Hoenen
- Laboratory for Integrative Cell and Infection Biology, Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Insel Riems, Greifswald 17493, Germany
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17
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Inhibiting the transcription and replication of Ebola viruses by disrupting the nucleoprotein and VP30 protein interaction with small molecules. Acta Pharmacol Sin 2023:10.1038/s41401-023-01055-0. [PMID: 36759643 PMCID: PMC9909651 DOI: 10.1038/s41401-023-01055-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 01/10/2023] [Indexed: 02/11/2023] Open
Abstract
Ebola virus (EBOV) causes hemorrhagic fever in humans with high morbidity and fatality. Although over 45 years have passed since the first EBOV outbreak, small molecule drugs are not yet available. Ebola viral protein VP30 is a unique RNA synthesis cofactor, and the VP30/NP interaction plays a critical role in initiating the transcription and propagation of EBOV. Here, we designed a high-throughput screening technique based on a competitive binding assay to bind VP30 between an NP-derived peptide and a chemical compound. By screening a library of 8004 compounds, we obtained two lead compounds, Embelin and Kobe2602. The binding of these compounds to the VP30-NP interface was validated by dose-dependent competitive binding assay, surface plasmon resonance, and thermal shift assay. Moreover, the compounds were confirmed to inhibit the transcription and replication of the Ebola genome by a minigenome assay. Similar results were obtained for their two respective analogs (8-gingerol and Kobe0065). Interestingly, these two structurally different molecules exhibit synergistic binding to the VP30/NP interface. The antiviral efficacy (EC50) increased from 1 μM by Kobe0065 alone to 351 nM when Kobe0065 and Embelin were combined in a 4:1 ratio. The synergistic anti-EBOV effect provides a strong incentive for further developing these lead compounds in future studies.
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18
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Islam MR, Akash S, Rahman MM, Sharma R. Epidemiology, pathophysiology, transmission, genomic structure, treatment, and future perspectives of the novel Marburg virus outbreak. Int J Surg 2023; 109:36-38. [PMID: 36799786 PMCID: PMC10389455 DOI: 10.1097/js9.0000000000000096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Accepted: 11/20/2022] [Indexed: 02/18/2023]
Affiliation(s)
- Md Rezaul Islam
- Department of Pharmacy, Faculty of Allied Health Sciences, Daffodil International University, Dhaka, Bangladesh
| | - Shopnil Akash
- Department of Pharmacy, Faculty of Allied Health Sciences, Daffodil International University, Dhaka, Bangladesh
| | - Md Mominur Rahman
- Department of Pharmacy, Faculty of Allied Health Sciences, Daffodil International University, Dhaka, Bangladesh
| | - Rohit Sharma
- Department of Rasa Shastra and Bhaishajya Kalpana, Faculty of Ayurveda, Institute of Medical Science, Banaras Hindu University, Varanasi, India
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19
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Nahhas AF, Webster TJ. A review of treating viral outbreaks with self-assembled nanomaterial-like peptides: From Ebola to the Marburg virus. OPENNANO 2022. [DOI: 10.1016/j.onano.2022.100094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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20
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Heiden B, Mühlberger E, Lennon CW, Hume AJ. Labeling Ebola Virus with a Self-Splicing Fluorescent Reporter. Microorganisms 2022; 10:2110. [PMID: 36363701 PMCID: PMC9696229 DOI: 10.3390/microorganisms10112110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/20/2022] [Accepted: 10/24/2022] [Indexed: 07/21/2023] Open
Abstract
Inteins (intervening proteins) are polypeptides that interrupt the sequence of other proteins and remove themselves through protein splicing. In this intein-catalyzed reaction, the two peptide bonds surrounding the intein are rearranged to release the intein from the flanking protein sequences, termed N- and C-exteins, which are concurrently joined by a peptide bond. Because of this unique functionality, inteins have proven exceptionally useful in protein engineering. Previous work has demonstrated that heterologous proteins can be inserted within an intein, with both the intein and inserted protein retaining function, allowing for intein-containing genes to coexpress additional coding sequences. Here, we show that a fluorescent protein (ZsGreen) can be inserted within the Pyrococcus horikoshii RadA intein, with the hybrid protein (ZsG-Int) maintaining fluorescence and splicing capability. We used this system to create a recombinant Ebola virus expressing a fluorescent protein. We first tested multiple potential insertion sites for ZsG-Int within individual Ebola virus proteins, identifying a site within the VP30 gene that facilitated efficient intein splicing in mammalian cells while also preserving VP30 function. Next, we successfully rescued a virus containing the ZsG-Int-VP30 fusion protein, which displayed fluorescence in the infected cells. We thus report a new intein-based application for adding reporters to systems without the need to add additional genes. Further, this work highlights a novel reporter design, whereby the reporter is only made if the protein of interest is translated and does not remain fused to the protein of interest.
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Affiliation(s)
- Baylee Heiden
- 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
| | | | - 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
- Center for Emerging Infectious Diseases Policy & Research, Boston University, Boston, MA 02118, USA
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21
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Edwards MR, Vogel OA, Mori H, Davey RA, Basler CF. Marburg Virus VP30 Is Required for Transcription Initiation at the Glycoprotein Gene. mBio 2022; 13:e0224322. [PMID: 35997284 PMCID: PMC9601197 DOI: 10.1128/mbio.02243-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 08/08/2022] [Indexed: 12/04/2022] Open
Abstract
Marburg virus (MARV) is an enveloped, negative-sense RNA virus from the filovirus family that causes outbreaks of severe, frequently fatal illness in humans. Of the seven MARV proteins, the VP30 protein stands out because it is essential for viral growth but lacks a definitive function. Here, we used model MARV genome RNAs for one or two reporter genes and the MARV VP40, glycoprotein (GP), and VP24 genes to demonstrate that VP30 is dispensable for the transcription of some genes but critical for transcription reinitiation at the GP gene. This results in the loss of the expression of GP and downstream genes and the impaired production of infectious particles when VP30 is absent. Bicistronic minigenome assays demonstrate that the VP40 gene end/GP gene start junction specifically confers VP30 dependence. A region at the GP gene start site predicted to form a stem-loop contributes to VP30 dependence because the replacement of the GP stem-loop with corresponding sequences from the MARV VP35 gene relieves VP30 dependence. Finally, a Cys3-His zinc binding motif characteristic of filovirus VP30 proteins was demonstrated to be critical for reinitiation at GP. These findings address a long-standing gap in our understanding of MARV biology by defining a critical role for VP30 in MARV transcription. IMPORTANCE Marburg virus and Ebola virus encode VP30 proteins. While the role of VP30 in Ebola virus transcription has been well studied, the role of VP30 in the Marburg virus life cycle is not well understood. The work here demonstrates that different gene start sites within the Marburg viral genome have variable levels of dependence on Marburg virus VP30, with its expression being critical for transcription reinitiation at the GP gene start site. These findings address a long-standing question regarding Marburg virus VP30 function and further our understanding of how Marburg virus gene expression is regulated.
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Affiliation(s)
- Megan R. Edwards
- Center for Microbial Pathogenesis, Institute for Biomedical Sciences, Georgia State University, Atlanta, Georgia, USA
| | - Olivia A. Vogel
- Center for Microbial Pathogenesis, Institute for Biomedical Sciences, Georgia State University, Atlanta, Georgia, USA
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Hiroyuki Mori
- Department of Microbiology, National Emerging Infectious Diseases Laboratories, Boston University, Boston, Massachusetts, USA
| | - Robert A. Davey
- Department of Microbiology, National Emerging Infectious Diseases Laboratories, Boston University, Boston, Massachusetts, USA
| | - Christopher F. Basler
- Center for Microbial Pathogenesis, Institute for Biomedical Sciences, Georgia State University, Atlanta, Georgia, USA
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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22
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Evidence for Viral mRNA Export from Ebola Virus Inclusion Bodies by the Nuclear RNA Export Factor NXF1. J Virol 2022; 96:e0090022. [PMID: 36040180 PMCID: PMC9517727 DOI: 10.1128/jvi.00900-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Many negative-sense RNA viruses, including the highly pathogenic Ebola virus (EBOV), use cytoplasmic inclusion bodies (IBs) for viral RNA synthesis. However, it remains unclear how viral mRNAs are exported from these IBs for subsequent translation. We recently demonstrated that the nuclear RNA export factor 1 (NXF1) is involved in a late step in viral protein expression, i.e., downstream of viral mRNA transcription, and proposed it to be involved in this mRNA export process. We now provide further evidence for this function by showing that NXF1 is not required for translation of viral mRNAs, thus pinpointing its function to a step between mRNA transcription and translation. We further show that RNA binding of both NXF1 and EBOV NP is necessary for export of NXF1 from IBs, supporting a model in which NP hands viral mRNA over to NXF1 for export. Mapping of NP-NXF1 interactions allowed refinement of this model, revealing two separate interaction sites, one of them directly involving the RNA binding cleft of NP, even though these interactions are RNA-independent. Immunofluorescence analyses demonstrated that individual NXF1 domains are sufficient for its recruitment into IBs, and complementation assays helped to define NXF1 domains important for its function in the EBOV life cycle. Finally, we show that NXF1 is also required for protein expression of other viruses that replicate in cytoplasmic IBs, including Lloviu and Junín virus. These data suggest a role for NXF1 in viral mRNA export from IBs for various viruses, making it a potential target for broadly active antivirals. IMPORTANCE Filoviruses such as the Ebola virus (EBOV) cause severe hemorrhagic fevers with high case fatality rates and limited treatment options. The identification of virus-host cell interactions shared among several viruses would represent promising targets for the development of broadly active antivirals. In this study, we reveal the mechanistic details of how EBOV usurps the nuclear RNA export factor 1 (NXF1) to export viral mRNAs from viral inclusion bodies (IBs). We further show that NXF1 is not only required for the EBOV life cycle but also necessary for other viruses known to replicate in cytoplasmic IBs, including the filovirus Lloviu virus and the highly pathogenic arenavirus Junín virus. This suggests NXF1 as a promising target for the development of broadly active antivirals.
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Abstract
Ebola virus (EBOV) VP30 regulates viral genome transcription and replication by switching its phosphorylation status. However, the importance of VP30 phosphorylation and dephosphorylation in other viral replication processes such as nucleocapsid and virion assembly is unclear. Interestingly, VP30 is predominantly dephosphorylated by cellular phosphatases in viral inclusions, while it is phosphorylated in the released virions. Thus, uncertainties regarding how VP30 phosphorylation in nucleocapsids is achieved and whether VP30 phosphorylation provides any advantages in later steps in viral replication have arisen. In the present study, to characterize the roles of VP30 phosphorylation in nucleocapsid formation, we used electron microscopic analyses and live cell imaging systems. We identified VP30 localized to the surface of protrusions surrounding nucleoprotein (NP)-forming helical structures in the nucleocapsid, suggesting the involvement in assembly and transport of nucleocapsids. Interestingly, VP30 phosphorylation facilitated its association with nucleocapsid-like structures (NCLSs). On the contrary, VP30 phosphorylation does not influence the transport characteristics and NCLS number leaving from and coming back into viral inclusions, indicating that the phosphorylation status of VP30 is not a prerequisite for NCLS departure. Moreover, the phosphorylation status of VP30 did not cause major differences in nucleocapsid transport in authentic EBOV-infected cells. In the following budding step, the association of VP30 and its phosphorylation status did not influence the budding efficiency of virus-like particles. Taken together, it is plausible that EBOV may utilize the phosphorylation of VP30 for its selective association with nucleocapsids, without affecting nucleocapsid transport and virion budding processes. IMPORTANCE Ebola virus (EBOV) causes severe fevers with unusually high case fatality rates. The nucleocapsid provides the template for viral genome transcription and replication. Thus, understanding the regulatory mechanism behind its formation is important for the development of novel therapeutic approaches. Previously, we established a live-cell imaging system based on the ectopic expression of viral fluorescent fusion proteins, allowing the visualization and characterization of intracytoplasmic transport of nucleocapsid-like structures. EBOV VP30 is an essential transcriptional factor for viral genome synthesis, and, although its role in viral genome transcription and replication is well understood, the functional importance of VP30 phosphorylation in assembly of nucleocapsids is still unclear. Our work determines the localization of VP30 at the surface of ruffled nucleocapsids, which differs from the localization of polymerase in EBOV-infected cells. This study sheds light on the novel role of VP30 phosphorylation in nucleocapsid assembly, which is an important prerequisite for virion formation.
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24
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CAPG Is Required for Ebola Virus Infection by Controlling Virus Egress from Infected Cells. Viruses 2022; 14:v14091903. [PMID: 36146710 PMCID: PMC9505868 DOI: 10.3390/v14091903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 08/24/2022] [Accepted: 08/26/2022] [Indexed: 11/16/2022] Open
Abstract
The replication of Ebola virus (EBOV) is dependent upon actin functionality, especially at cell entry through macropinocytosis and at release of virus from cells. Previously, major actin-regulatory factors involved in actin nucleation, such as Rac1 and Arp2/3, were shown important in both steps. However, downstream of nucleation, many other cell factors are needed to control actin dynamics. How these regulate EBOV infection remains largely unclear. Here, we identified the actin-regulating protein, CAPG, as important for EBOV replication. Notably, knockdown of CAPG specifically inhibited viral infectivity and yield of infectious particles. Cell-based mechanistic analysis revealed a requirement of CAPG for virus production from infected cells. Proximity ligation and split-green fluorescent protein reconstitution assays revealed strong association of CAPG with VP40 that was mediated through the S1 domain of CAPG. Overall, CAPG is a novel host factor regulating EBOV infection through connecting actin filament stabilization to viral egress from cells.
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25
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Sun W, Luan F, Wang J, Ma L, Li X, Yang G, Hao C, Qin X, Dong S. Structural insights into the interactions between lloviu virus VP30 and nucleoprotein. Biochem Biophys Res Commun 2022; 616:82-88. [PMID: 35649303 DOI: 10.1016/j.bbrc.2022.05.059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Accepted: 05/17/2022] [Indexed: 11/19/2022]
Abstract
The family Filoviridae comprises many notorious viruses, such as Ebola virus (EBOV) and Marburg virus (MARV), that can infect humans and nonhuman primates. Lloviu virus (LLOV), a less well studied filovirus, is considered a potential pathogen for humans. The VP30 C-terminal domain (CTD) of these filoviruses exhibits nucleoprotein (NP) binding and plays an essential role in viral transcription, replication and assembly. In this study, we confirmed the interactions between LLOV VP30 CTD and its NP fragment, and also determined the crystal structure of the chimeric dimeric LLOV NP-VP30 CTD at 2.50 Å resolution. The structure is highly conserved across the family Filoviridae. While in the dimer structure, only one VP30 CTD binds the NP fragment, which indicates that the interaction between LLOV VP30 CTD and NP is not strong. Our work provides a preliminary model to investigate the interactions between LLOV VP30 and NP and suggests a potential target for anti-filovirus drug development.
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Affiliation(s)
- Weiyan Sun
- School of Biological Science and Technology, University of Jinan, Jinan, China
| | - Fuchen Luan
- School of Biological Science and Technology, University of Jinan, Jinan, China
| | - Jiajia Wang
- School of Biological Science and Technology, University of Jinan, Jinan, China
| | - Lin Ma
- School of Biological Science and Technology, University of Jinan, Jinan, China
| | - Xiuxiu Li
- School of Chemistry and Chemical Engineering, University of Jinan, Jinan, China
| | - Gongxian Yang
- School of Chemistry and Chemical Engineering, University of Jinan, Jinan, China
| | - Chenyang Hao
- School of Biological Science and Technology, University of Jinan, Jinan, China
| | - Xiaochun Qin
- School of Biological Science and Technology, University of Jinan, Jinan, China; School of Chemistry and Chemical Engineering, University of Jinan, Jinan, China.
| | - Shishang Dong
- School of Biological Science and Technology, University of Jinan, Jinan, China.
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26
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Loh D, Reiter RJ. Melatonin: Regulation of Viral Phase Separation and Epitranscriptomics in Post-Acute Sequelae of COVID-19. Int J Mol Sci 2022; 23:8122. [PMID: 35897696 PMCID: PMC9368024 DOI: 10.3390/ijms23158122] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 07/09/2022] [Accepted: 07/20/2022] [Indexed: 01/27/2023] Open
Abstract
The relentless, protracted evolution of the SARS-CoV-2 virus imposes tremendous pressure on herd immunity and demands versatile adaptations by the human host genome to counter transcriptomic and epitranscriptomic alterations associated with a wide range of short- and long-term manifestations during acute infection and post-acute recovery, respectively. To promote viral replication during active infection and viral persistence, the SARS-CoV-2 envelope protein regulates host cell microenvironment including pH and ion concentrations to maintain a high oxidative environment that supports template switching, causing extensive mitochondrial damage and activation of pro-inflammatory cytokine signaling cascades. Oxidative stress and mitochondrial distress induce dynamic changes to both the host and viral RNA m6A methylome, and can trigger the derepression of long interspersed nuclear element 1 (LINE1), resulting in global hypomethylation, epigenetic changes, and genomic instability. The timely application of melatonin during early infection enhances host innate antiviral immune responses by preventing the formation of "viral factories" by nucleocapsid liquid-liquid phase separation that effectively blockades viral genome transcription and packaging, the disassembly of stress granules, and the sequestration of DEAD-box RNA helicases, including DDX3X, vital to immune signaling. Melatonin prevents membrane depolarization and protects cristae morphology to suppress glycolysis via antioxidant-dependent and -independent mechanisms. By restraining the derepression of LINE1 via multifaceted strategies, and maintaining the balance in m6A RNA modifications, melatonin could be the quintessential ancient molecule that significantly influences the outcome of the constant struggle between virus and host to gain transcriptomic and epitranscriptomic dominance over the host genome during acute infection and PASC.
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Affiliation(s)
- Doris Loh
- Independent Researcher, Marble Falls, TX 78654, USA;
| | - Russel J. Reiter
- Department of Cell Systems and Anatomy, UT Health San Antonio, San Antonio, TX 78229, USA
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27
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Abstract
Filovirus-infected cells are characterized by typical cytoplasmic inclusion bodies (IBs) located in the perinuclear region. The formation of these IBs is induced mainly by the accumulation of the filoviral nucleoprotein NP, which recruits the other nucleocapsid proteins, the polymerase co-factor VP35, the polymerase L, the transcription factor VP30 and VP24 via direct or indirect protein-protein interactions. Replication of the negative-strand RNA genomes by the viral polymerase L and VP35 occurs in the IBs, resulting in the synthesis of positive-strand genomes, which are encapsidated by NP, thus forming ribonucleoprotein complexes (antigenomic RNPs). These newly formed antigenomic RNPs in turn serve as templates for the synthesis of negative-strand RNA genomes that are also encapsidated by NP (genomic RNPs). Still in the IBs, genomic RNPs mature into tightly packed transport-competent nucleocapsids (NCs) by the recruitment of the viral protein VP24. NCs are tightly coiled left-handed helices whose structure is mainly determined by the multimerization of NP at its N-terminus, and these helices form the inner layer of the NCs. The RNA genome is fixed by 2 lobes of the NP N-terminus and is thus guided by individual NP molecules along the turns of the helix. Direct interaction of the NP C-terminus with the VP35 and VP24 molecules forms the outer layer of the NCs. Once formed, NCs that are located at the border of the IBs recruit actin polymerization machinery to one of their ends to drive their transport to budding sites for their envelopment and final release. Here, we review the current knowledge on the structure, assembly, and transport of filovirus NCs.
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Affiliation(s)
- Olga Dolnik
- Institute of Virology, Philipps-University Marburg, Marburg, Germany
| | - Stephan Becker
- Institute of Virology, Philipps-University Marburg, Marburg, Germany
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28
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Assessment of Life Cycle Modeling Systems as Prediction Tools for a Possible Attenuation of Recombinant Ebola Viruses. Viruses 2022; 14:v14051044. [PMID: 35632785 PMCID: PMC9147524 DOI: 10.3390/v14051044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 05/12/2022] [Accepted: 05/13/2022] [Indexed: 11/17/2022] Open
Abstract
Ebola virus (EBOV) causes hemorrhagic fever in humans with high case fatality rates. In the past, a number of recombinant EBOVs expressing different reporters from additional transcription units or as fusion proteins have been rescued. These viruses are important tools for the study of EBOV, and their uses include high throughput screening approaches, the analysis of intercellular localization of viral proteins and of tissue distribution of viruses, and the study of pathogenesis in vivo. However, they all show, at least in vivo, attenuation compared to wild type virus, and the basis of this attenuation is only poorly understood. Unfortunately, rescue of these viruses is a lengthy and not always successful process, and working with them is restricted to biosafety level (BSL)-4 laboratories, so that the search for non-attenuated reporter-expressing EBOVs remains challenging. However, several life cycle modeling systems have been developed to mimic different aspects of the filovirus life cycle under BSL-1 or -2 conditions, but it remains unclear whether these systems can be used to predict the viability and possible attenuation of recombinant EBOVs. To address this question, we systematically fused N- or C-terminally either a flag-HA tag or a green fluorescent protein (GFP) to different EBOV proteins, and analyzed the impact of these additions with respect to protein function in life cycle modeling systems. Based on these results, selected recombinant EBOVs encoding these tags/proteins were then rescued and characterized for a possible attenuation in vitro, and results compared with data from the life cycle modeling systems. While the results for the small molecular tags showed mostly good concordance, GFP-expressing viruses were more attenuated than expected based on the results from the life cycle modeling system, demonstrating a limitation of these systems and emphasizing the importance of work with infectious virus. Nevertheless, life cycle modeling system remain useful tools to exclude non-viable tagging strategies.
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29
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Galão RP, Wilson H, Schierhorn KL, Debeljak F, Bodmer BS, Goldhill D, Hoenen T, Wilson SJ, Swanson CM, Neil SJD. TRIM25 and ZAP target the Ebola virus ribonucleoprotein complex to mediate interferon-induced restriction. PLoS Pathog 2022; 18:e1010530. [PMID: 35533151 PMCID: PMC9119685 DOI: 10.1371/journal.ppat.1010530] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 05/19/2022] [Accepted: 04/18/2022] [Indexed: 12/14/2022] Open
Abstract
Ebola virus (EBOV) causes highly pathogenic disease in primates. Through screening a library of human interferon-stimulated genes (ISGs), we identified TRIM25 as a potent inhibitor of EBOV transcription-and-replication-competent virus-like particle (trVLP) propagation. TRIM25 overexpression inhibited the accumulation of viral genomic and messenger RNAs independently of the RNA sensor RIG-I or secondary proinflammatory gene expression. Deletion of TRIM25 strongly attenuated the sensitivity of trVLPs to inhibition by type-I interferon. The antiviral activity of TRIM25 required ZAP and the effect of type-I interferon was modulated by the CpG dinucleotide content of the viral genome. We find that TRIM25 interacts with the EBOV vRNP, resulting in its autoubiquitination and ubiquitination of the viral nucleoprotein (NP). TRIM25 is recruited to incoming vRNPs shortly after cell entry and leads to dissociation of NP from the vRNA. We propose that TRIM25 targets the EBOV vRNP, exposing CpG-rich viral RNA species to restriction by ZAP.
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Affiliation(s)
- Rui Pedro Galão
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King’s College London, United Kingdom
| | - Harry Wilson
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King’s College London, United Kingdom
| | - Kristina L. Schierhorn
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King’s College London, United Kingdom
| | - Franka Debeljak
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King’s College London, United Kingdom
| | - Bianca S. Bodmer
- Institute for Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald, Germany
| | - Daniel Goldhill
- Section of Virology, Department of Medicine, Imperial College London, London, United Kingdom
| | - Thomas Hoenen
- Institute for Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald, Germany
| | - Sam J. Wilson
- MRC Centre for Virus Research, University of Glasgow, United Kingdom
| | - Chad M. Swanson
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King’s College London, United Kingdom
| | - Stuart J. D. Neil
- Department of Infectious Diseases, School of Immunology and Microbial Sciences, King’s College London, United Kingdom
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30
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van Tol S, Kalveram B, Ilinykh PA, Ronk A, Huang K, Aguilera-Aguirre L, Bharaj P, Hage A, Atkins C, Giraldo MI, Wakamiya M, Gonzalez-Orozco M, Warren AN, Bukreyev A, Freiberg AN, Rajsbaum R. Ubiquitination of Ebola virus VP35 at lysine 309 regulates viral transcription and assembly. PLoS Pathog 2022; 18:e1010532. [PMID: 35533195 PMCID: PMC9119628 DOI: 10.1371/journal.ppat.1010532] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 05/19/2022] [Accepted: 04/18/2022] [Indexed: 11/18/2022] Open
Abstract
Ebola virus (EBOV) VP35 is a polyfunctional protein involved in viral genome packaging, viral polymerase function, and host immune antagonism. The mechanisms regulating VP35's engagement in different functions are not well-understood. We previously showed that the host E3 ubiquitin ligase TRIM6 ubiquitinates VP35 at lysine 309 (K309) to facilitate virus replication. However, how K309 ubiquitination regulates the function of VP35 as the viral polymerase co-factor and the precise stage(s) of the EBOV replication cycle that require VP35 ubiquitination are not known. Here, we generated recombinant EBOVs encoding glycine (G) or arginine (R) mutations at VP35/K309 (rEBOV-VP35/K309G/-R) and show that both mutations prohibit VP35/K309 ubiquitination. The K309R mutant retains dsRNA binding and efficient type-I Interferon (IFN-I) antagonism due to the basic residue conservation. The rEBOV-VP35/K309G mutant loses the ability to efficiently antagonize the IFN-I response, while the rEBOV-VP35/K309R mutant's suppression is enhanced. The replication of both mutants was significantly attenuated in both IFN-competent and -deficient cells due to impaired interactions with the viral polymerase. The lack of ubiquitination on VP35/K309 or TRIM6 deficiency disrupts viral transcription with increasing severity along the transcriptional gradient. This disruption of the transcriptional gradient results in unbalanced viral protein production, including reduced synthesis of the viral transcription factor VP30. In addition, lack of ubiquitination on K309 results in enhanced interactions with the viral nucleoprotein and premature nucleocapsid packaging, leading to dysregulation of virus assembly. Overall, we identified a novel role of VP35 ubiquitination in coordinating viral transcription and assembly.
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Affiliation(s)
- Sarah van Tol
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Birte Kalveram
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Philipp A. Ilinykh
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Galveston National Laboratory, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Adam Ronk
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Galveston National Laboratory, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Kai Huang
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Galveston National Laboratory, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Leopoldo Aguilera-Aguirre
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Preeti Bharaj
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Galveston National Laboratory, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Adam Hage
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Colm Atkins
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Maria I. Giraldo
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Maki Wakamiya
- Transgenic Mouse Core Facility, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Maria Gonzalez-Orozco
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Abbey N. Warren
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Alexander Bukreyev
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Galveston National Laboratory, University of Texas Medical Branch, Galveston, Texas, United States of America
- Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Alexander N. Freiberg
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Galveston National Laboratory, University of Texas Medical Branch, Galveston, Texas, United States of America
- Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, Texas, United States of America
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Ricardo Rajsbaum
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, Texas, United States of America
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31
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Abir MH, Rahman T, Das A, Etu SN, Nafiz IH, Rakib A, Mitra S, Emran TB, Dhama K, Islam A, Siyadatpanah A, Mahmud S, Kim B, Hassan MM. Pathogenicity and virulence of Marburg virus. Virulence 2022; 13:609-633. [PMID: 35363588 PMCID: PMC8986239 DOI: 10.1080/21505594.2022.2054760] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Marburg virus (MARV) has been a major concern since 1967, with two major outbreaks occurring in 1998 and 2004. Infection from MARV results in severe hemorrhagic fever, causing organ dysfunction and death. Exposure to fruit bats in caves and mines, and human-to-human transmission had major roles in the amplification of MARV outbreaks in African countries. The high fatality rate of up to 90% demands the broad study of MARV diseases (MVD) that correspond with MARV infection. Since large outbreaks are rare for MARV, clinical investigations are often inadequate for providing the substantial data necessary to determine the treatment of MARV disease. Therefore, an overall review may contribute to minimizing the limitations associated with future medical research and improve the clinical management of MVD. In this review, we sought to analyze and amalgamate significant information regarding MARV disease epidemics, pathophysiology, and management approaches to provide a better understanding of this deadly virus and the associated infection.
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Affiliation(s)
- Mehedy Hasan Abir
- Faculty of Food Science and Technology, Chattogram Veterinary and Animal Sciences University, Chittagong, Bangladesh
| | - Tanjilur Rahman
- Department of Biochemistry and Molecular Biology, Faculty of Biological Sciences, University of Chittagong, Chittagong, Bangladesh
| | - Ayan Das
- Department of Biochemistry and Molecular Biology, Faculty of Biological Sciences, University of Chittagong, Chittagong, Bangladesh
| | - Silvia Naznin Etu
- Department of Genetic Engineering and Biotechnology, Faculty of Biological Sciences, University of Chittagong, Chittagong, Bangladesh
| | - Iqbal Hossain Nafiz
- Department of Biochemistry and Molecular Biology, Faculty of Biological Sciences, University of Chittagong, Chittagong, Bangladesh
| | - Ahmed Rakib
- Department of Pharmacy, Faculty of Biological Sciences, University of Chittagong, Chittagong, Bangladesh
| | - Saikat Mitra
- Department of Pharmacy, Faculty of Pharmacy, University of Dhaka, Dhaka, Bangladesh
| | - Talha Bin Emran
- Department of Pharmacy, BGC Trust University Bangladesh, Chittagong, Bangladesh
| | - Kuldeep Dhama
- Division of Pathology, ICAR-Indian Veterinary Research Institute, Bareilly, India
| | - Ariful Islam
- EcoHealth Alliance, New York, NY, USA.,Centre for Integrative Ecology, School of Life and Environmental Science, Deakin University, Victoria, Australia
| | - Abolghasem Siyadatpanah
- Ferdows School of Paramedical and Health, Birjand University of Medical Sciences, Birjand, Iran
| | - Shafi Mahmud
- Genetic Engineering and Biotechnology, University of Rajshahi, Rajshahi, Bangladesh
| | - Bonlgee Kim
- Department of Pathology, College of Korean Medicine, Kyung Hee University, Seoul, Korea
| | - Mohammad Mahmudul Hassan
- Queensland Alliance for One Health Sciences, School of Veterinary Sciences, The University of Queensland, Gatton, Australia.,Department of Physiology, Biochemistry and Pharmacology, Faculty of Veterinary Medicine, Chattogram Veterinary and Animal Sciences University, Chattogram, Bangladesh
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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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Liu CH, Hu YT, Wong SH, Lin LT. Therapeutic Strategies against Ebola Virus Infection. Viruses 2022; 14:v14030579. [PMID: 35336986 PMCID: PMC8954160 DOI: 10.3390/v14030579] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 03/03/2022] [Accepted: 03/08/2022] [Indexed: 12/10/2022] Open
Abstract
Since the 2014–2016 epidemic, Ebola virus (EBOV) has spread to several countries and has become a major threat to global health. EBOV is a risk group 4 pathogen, which imposes significant obstacles for the development of countermeasures against the virus. Efforts have been made to develop anti-EBOV immunization and therapeutics, with three vaccines and two antibody-based therapeutics approved in recent years. Nonetheless, the high fatality of Ebola virus disease highlights the need to continuously develop antiviral strategies for the future management of EBOV outbreaks in conjunction with vaccination programs. This review aims to highlight potential EBOV therapeutics and their target(s) of inhibition, serving as a summary of the literature to inform readers of the novel candidates available in the continued search for EBOV antivirals.
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Affiliation(s)
- Ching-Hsuan Liu
- Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan;
| | - Yee-Tung Hu
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei 110, Taiwan;
| | - Shu Hui Wong
- International Ph.D. Program in Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan;
| | - Liang-Tzung Lin
- Department of Microbiology and Immunology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan;
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei 110, Taiwan;
- Correspondence:
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Bhattarai N, Pavadai E, Pokhrel R, Baral P, Hossen L, Stahelin RV, Chapagain PP, Gerstman BS. Ebola virus protein VP40 binding to Sec24c for transport to the plasma membrane. Proteins 2022; 90:340-350. [PMID: 34431571 PMCID: PMC8738135 DOI: 10.1002/prot.26221] [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: 01/29/2021] [Revised: 07/01/2021] [Accepted: 08/16/2021] [Indexed: 02/03/2023]
Abstract
Outbreaks of the Ebola virus (EBOV) continue to occur and while a vaccine and treatment are now available, there remains a dearth of options for those who become sick with EBOV disease. An understanding at the atomic and molecular level of the various steps in the EBOV replication cycle can provide molecular targets for disrupting the virus. An important step in the EBOV replication cycle is the transport of EBOV structural matrix VP40 protein molecules to the plasma membrane inner leaflet, which involves VP40 binding to the host cell's Sec24c protein. Though some VP40 residues involved in the binding are known, the molecular details of VP40-Sec24c binding are not known. We use various molecular computational techniques to investigate the molecular details of how EBOV VP40 binds with the Sec24c complex of the ESCRT-I pathway. We employed different docking programs to identify the VP40-binding site on Sec24c and then performed molecular dynamics simulations to determine the atomic details and binding interactions of the complex. We also investigated how the inter-protein interactions of the complex are affected upon mutations of VP40 amino acids in the Sec24c-binding region. Our results provide a molecular basis for understanding previous coimmunoprecipitation experimental studies. In addition, we found that VP40 can bind to a site on Sec24c that can also bind Sec23 and suggests that VP40 may use the COPII transport mechanism in a manner that may not need the Sec23 protein in order for VP40 to be transported to the plasma membrane.
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Affiliation(s)
- Nisha Bhattarai
- Department of Physics, Florida International University, Miami, FL 33199, USA
| | - Elumalai Pavadai
- Department of Physics, Florida International University, Miami, FL 33199, USA
| | - Rudramani Pokhrel
- Department of Physics, Florida International University, Miami, FL 33199, USA
| | - Prabin Baral
- Department of Physics, Florida International University, Miami, FL 33199, USA
| | - Lokman Hossen
- Department of Physics, Florida International University, Miami, FL 33199, USA
| | - Robert V. Stahelin
- Department of Medicinal Chemistry & Molecular Pharmacology and the Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette IN 47906
| | - Prem P. Chapagain
- Department of Physics, Florida International University, Miami, FL 33199, USA
- Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA
| | - Bernard S. Gerstman
- Department of Physics, Florida International University, Miami, FL 33199, USA
- Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA
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Corona A, Fanunza E, Salata C, Morwitzer MJ, Distinto S, Zinzula L, Sanna C, Frau A, Daino GL, Quartu M, Taglialatela-Scafati O, Rigano D, Reid S, Mirazimi A, Tramontano E. Cynarin blocks Ebola virus replication by counteracting VP35 inhibition of interferon-beta production. Antiviral Res 2022; 198:105251. [DOI: 10.1016/j.antiviral.2022.105251] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 12/16/2021] [Accepted: 01/17/2022] [Indexed: 11/02/2022]
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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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Functional Importance of Hydrophobic Patches on the Ebola Virus VP35 IFN-Inhibitory Domain. Viruses 2021; 13:v13112316. [PMID: 34835122 PMCID: PMC8618116 DOI: 10.3390/v13112316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 11/04/2021] [Accepted: 11/09/2021] [Indexed: 11/23/2022] Open
Abstract
Viral protein 35 (VP35) of Ebola virus (EBOV) is a multifunctional protein that mainly acts as a viral polymerase cofactor and an interferon antagonist. VP35 interacts with the viral nucleoprotein (NP) and double-stranded RNA for viral RNA transcription/replication and inhibition of type I interferon (IFN) production, respectively. The C-terminal portion of VP35, which is termed the IFN-inhibitory domain (IID), is important for both functions. To further identify critical regions in this domain, we analyzed the physical properties of the surface of VP35 IID, focusing on hydrophobic patches, which are expected to be functional sites that are involved in interactions with other molecules. Based on the known structural information of VP35 IID, three hydrophobic patches were identified on its surface and their biological importance was investigated using minigenome and IFN-β promoter-reporter assays. Site-directed mutagenesis revealed that some of the amino acid substitutions that were predicted to disrupt the hydrophobicity of the patches significantly decreased the efficiency of viral genome replication/transcription due to reduced interaction with NP, suggesting that the hydrophobic patches might be critical for the formation of a replication complex through the interaction with NP. It was also found that the hydrophobic patches were involved in the IFN-inhibitory function of VP35. These results highlight the importance of hydrophobic patches on the surface of EBOV VP35 IID and also indicate that patch analysis is useful for the identification of amino acid residues that directly contribute to protein functions.
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38
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Bach S, Demper JC, Klemm P, Schlereth J, Lechner M, Schoen A, Kämper L, Weber F, Becker S, Biedenkopf N, Hartmann RK. Identification and characterization of short leader and trailer RNAs synthesized by the Ebola virus RNA polymerase. PLoS Pathog 2021; 17:e1010002. [PMID: 34699554 PMCID: PMC8547711 DOI: 10.1371/journal.ppat.1010002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 10/04/2021] [Indexed: 11/21/2022] Open
Abstract
Transcription of non-segmented negative sense (NNS) RNA viruses follows a stop-start mechanism and is thought to be initiated at the genome’s very 3’-end. The synthesis of short abortive leader transcripts (leaderRNAs) has been linked to transcription initiation for some NNS viruses. Here, we identified the synthesis of abortive leaderRNAs (as well as trailer RNAs) that are specifically initiated opposite to (anti)genome nt 2; leaderRNAs are predominantly terminated in the region of nt ~ 60–80. LeaderRNA synthesis requires hexamer phasing in the 3’-leader promoter. We determined a steady-state NP mRNA:leaderRNA ratio of ~10 to 30-fold at 48 h after Ebola virus (EBOV) infection, and this ratio was higher (70 to 190-fold) for minigenome-transfected cells. LeaderRNA initiation at nt 2 and the range of termination sites were not affected by structure and length variation between promoter elements 1 and 2, nor the presence or absence of VP30. Synthesis of leaderRNA is suppressed in the presence of VP30 and termination of leaderRNA is not mediated by cryptic gene end (GE) signals in the 3’-leader promoter. We further found different genomic 3’-end nucleotide requirements for transcription versus replication, suggesting that promoter recognition is different in the replication and transcription mode of the EBOV polymerase. We further provide evidence arguing against a potential role of EBOV leaderRNAs as effector molecules in innate immunity. Taken together, our findings are consistent with a model according to which leaderRNAs are abortive replicative RNAs whose synthesis is not linked to transcription initiation. Rather, replication and transcription complexes are proposed to independently initiate RNA synthesis at separate sites in the 3’-leader promoter, i.e., at the second nucleotide of the genome 3’-end and at the more internally positioned transcription start site preceding the first gene, respectively, as reported for Vesicular stomatitis virus. The RNA polymerase (RdRp) of Ebola virus (EBOV) initiates RNA synthesis at the 3’-leader promoter of its encapsidated, non-segmented negative sense (NNS) RNA genome, either at the penultimate 3’-end position of the genome in the replicative mode or more internally (position 56) at the transcription start site (TSS) in its transcription mode. Here we identified the synthesis of abortive replicative RNAs that are specifically initiated opposite to genome nt 2 (termed leaderRNAs) and predominantly terminated in the region of nt ~ 60–80 near the TSS. The functional role of abortive leaderRNA synthesis is still enigmatic; a role in interferon induction could be excluded. Our findings indirectly link leaderRNA termination to nucleoprotein (NP) availability for encapsidation of nascent replicative RNA or to NP removal from the template RNA. Our findings further argue against the model that leaderRNA synthesis is a prerequisite for each transcription initiation event at the TSS. Rather, our findings are in line with the existence of distinct replicase and transcriptase complexes of RdRp that interact differently with the 3’-leader promoter and intiate RNA synthesis independently at different sites (position 2 or 56 of the genome), mechanistically similar to another NNS virus, Vesicular stomatitis virus.
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Affiliation(s)
- Simone Bach
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marburg, Germany
| | - Jana-Christin Demper
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marburg, Germany
| | - Paul Klemm
- Zentrum für Synthetische Mikrobiologie, Philipps-Universität Marburg, Marburg, Germany
| | - Julia Schlereth
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marburg, Germany
| | - Marcus Lechner
- Zentrum für Synthetische Mikrobiologie, Philipps-Universität Marburg, Marburg, Germany
| | - Andreas Schoen
- Institut für Virologie, Justus-Liebig-Universität Gießen, Gießen, Germany
| | - Lennart Kämper
- Institut für Virologie, Philipps-Universität Marburg, Marburg, Germany
| | - Friedemann Weber
- Institut für Virologie, Justus-Liebig-Universität Gießen, Gießen, Germany
| | - Stephan Becker
- Institut für Virologie, Philipps-Universität Marburg, Marburg, Germany
| | - Nadine Biedenkopf
- Institut für Virologie, Philipps-Universität Marburg, Marburg, Germany
- * E-mail: (NB); (RKH)
| | - Roland K. Hartmann
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marburg, Germany
- * E-mail: (NB); (RKH)
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Bhattacharyya S. Mechanisms of Immune Evasion by Ebola Virus. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1313:15-22. [PMID: 34661889 DOI: 10.1007/978-3-030-67452-6_2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
The 2013-2016 Ebola virus epidemic in West Africa, which also spread to the USA, UK and Europe, was the largest reported outbreak till date (World Health Organization. 2016. https://apps.who.int/iris/bitstream/handle/10665/208883/ebolasitrep_10Jun2016_eng.pdf;jsessionid=8B7D74BC9D82D2BE1B110BAFFAD3A6E6?sequence=1 ). The recent Ebola outbreak in the Democratic Republic of the Congo has raised immense global concern on this severe and often fatal infection. Although sporadic, the severity and lethality of Ebola virus disease outbreaks has led to extensive research worldwide on this virus. Vaccine (World Health Organization. 2016. https://www.who.int/en/news-room/detail/23-12-2016-final-trial-results-confirm-ebola-vaccine-provides-high-protection-against-disease ; Henao-Restrepo et al. Lancet 389:505-518, 2017) and drug (Hayden. Nature, 557, 475-476, 2018; Dyall et al. J Infect Dis 218(suppl_5), S672-S678, 2018) development efforts against Ebola virus are research hotspots, and a few approved therapeutics are currently available (Centers for Disease Control and Prevention. 2021. https://www.cdc.gov/vhf/ebola/clinicians/vaccine/index.html; Centers for Disease Control and Prevention. 2021. https://www.cdc.gov/vhf/ebola/treatment/index.html). Ebola virus has evolved several mechanisms of host immune evasion, which facilitate its replication and pathogenesis. This chapter describes the Ebola virus morphology, genome, entry, replication, pathogenesis and viral proteins involved in host immune evasion. Further understanding of the underlying molecular mechanisms of immune evasion may facilitate development of additional novel and sustainable strategies against this deadly virus.
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Affiliation(s)
- Suchita Bhattacharyya
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, UK.
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40
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Structural and Functional Aspects of Ebola Virus Proteins. Pathogens 2021; 10:pathogens10101330. [PMID: 34684279 PMCID: PMC8538763 DOI: 10.3390/pathogens10101330] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Revised: 10/11/2021] [Accepted: 10/14/2021] [Indexed: 01/14/2023] Open
Abstract
Ebola virus (EBOV), member of genus Ebolavirus, family Filoviridae, have a non-segmented, single-stranded RNA that contains seven genes: (a) nucleoprotein (NP), (b) viral protein 35 (VP35), (c) VP40, (d) glycoprotein (GP), (e) VP30, (f) VP24, and (g) RNA polymerase (L). All genes encode for one protein each except GP, producing three pre-proteins due to the transcriptional editing. These pre-proteins are translated into four products, namely: (a) soluble secreted glycoprotein (sGP), (b) Δ-peptide, (c) full-length transmembrane spike glycoprotein (GP), and (d) soluble small secreted glycoprotein (ssGP). Further, shed GP is released from infected cells due to cleavage of GP by tumor necrosis factor α-converting enzyme (TACE). This review presents a detailed discussion on various functional aspects of all EBOV proteins and their residues. An introduction to ebolaviruses and their life cycle is also provided for clarity of the available analysis. We believe that this review will help understand the roles played by different EBOV proteins in the pathogenesis of the disease. It will help in targeting significant protein residues for therapeutic and multi-protein/peptide vaccine development.
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41
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On-Demand Patient-Specific Phenotype-to-Genotype Ebola Virus Characterization. Viruses 2021; 13:v13102010. [PMID: 34696439 PMCID: PMC8537714 DOI: 10.3390/v13102010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 09/28/2021] [Accepted: 09/29/2021] [Indexed: 11/17/2022] Open
Abstract
Biosafety, biosecurity, logistical, political, and technical considerations can delay or prevent the wide dissemination of source material containing viable virus from the geographic origin of an outbreak to laboratories involved in developing medical countermeasures (MCMs). However, once virus genome sequence information is available from clinical samples, reverse-genetics systems can be used to generate virus stocks de novo to initiate MCM development. In this study, we developed a reverse-genetics system for natural isolates of Ebola virus (EBOV) variants Makona, Tumba, and Ituri, which have been challenging to obtain. These systems were generated starting solely with in silico genome sequence information and have been used successfully to produce recombinant stocks of each of the viruses for use in MCM testing. The antiviral activity of MCMs targeting viral entry varied depending on the recombinant virus isolate used. Collectively, selecting and synthetically engineering emerging EBOV variants and demonstrating their efficacy against available MCMs will be crucial for answering pressing public health and biosecurity concerns during Ebola disease (EBOD) outbreaks.
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Comparison of Zaire and Bundibugyo ebolavirus polymerase complexes and susceptibility to antivirals through a newly developed Bundibugyo minigenome system. J Virol 2021; 95:e0064321. [PMID: 34379503 DOI: 10.1128/jvi.00643-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Members of the genus Ebolavirus cause lethal disease in humans with Zaire ebolavirus (EBOV) being the most pathogenic (up to 90% morality) and Bundibugyo ebolavirus (BDBV) the least pathogenic (∼37% mortality). Historically, there has been a lack of research on BDBV and there is no means to study BDBV outside of a high-containment laboratory. Here, we describe a minigenome replication system to study BDBV transcription and compare the efficacy of small molecule inhibtors between EBOV and BDBV. Using this system, we examined the ability of the polymerase complex proteins from EBOV and BDBV to interact and form a functional unit as well as the impact of the genomic untranslated ends, known to contain important signals for transcription (3'-untranslated region) and replication (5'-untranslated region). Varying levels of compatibility were observed between proteins of the polymerase complex from each ebolavirus resulting in differences in genome transcription efficiency. Most pronounced was the effect of the nucleoprotein and the 3'-untranslated region. These data suggest that there are intrinsic specificities in the polymerase complex and untranslated signaling regions that could offer insight regarding observed pathogenic differences. Further adding to the differences in the polymerase complexes, post-transfection/infection treatment with the compound remdesivir (GS-5734) showed a greater inhibitory effect against BDBV compared to EBOV. The delayed growth kinetics of BDBV and the greater susceptibility to polymerase inhibitors indicate that disruption of the polymerase complex may be a viable target for therapeutics. Importance Ebolavirus disease is a viral infection and is fatal in 25-90% of cases, depending on the viral species and the amount of supportive care available. Two species have caused outbreaks in the Democratic Republic of the Congo, Zaire ebolavirus (EBOV) and Bundibugyo ebolavirus (BDBV). Pathogenesis and clinical outcome differ between these two species but there is still limited information regarding the viral mechanism for these differences. Previous studies suggest that BDBV replicates slower than EBOV but it is unknown if this is due to differences in the polymerase complex and its role in transcription and replication. This study details the construction of a minigenome replication system which can be used in a biosafety level (BSL) 2 laboartory. This system will be important for studying the polymerase complex of BDBV and comparing it with other filoviruses and can be used as a tool for screening inhibitors of viral growth.
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Batra J, Mori H, Small GI, Anantpadma M, Shtanko O, Mishra N, Zhang M, Liu D, Williams CG, Biedenkopf N, Becker S, Gross ML, Leung DW, Davey RA, Amarasinghe GK, Krogan NJ, Basler CF. Non-canonical proline-tyrosine interactions with multiple host proteins regulate Ebola virus infection. EMBO J 2021; 40:e105658. [PMID: 34260076 DOI: 10.15252/embj.2020105658] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 06/23/2021] [Accepted: 07/09/2021] [Indexed: 01/08/2023] Open
Abstract
The Ebola virus VP30 protein interacts with the viral nucleoprotein and with host protein RBBP6 via PPxPxY motifs that adopt non-canonical orientations, as compared to other proline-rich motifs. An affinity tag-purification mass spectrometry approach identified additional PPxPxY-containing host proteins hnRNP L, hnRNPUL1, and PEG10, as VP30 interactors. hnRNP L and PEG10, like RBBP6, inhibit viral RNA synthesis and EBOV infection, whereas hnRNPUL1 enhances. RBBP6 and hnRNP L modulate VP30 phosphorylation, increase viral transcription, and exert additive effects on viral RNA synthesis. PEG10 has more modest inhibitory effects on EBOV replication. hnRNPUL1 positively affects viral RNA synthesis but in a VP30-independent manner. Binding studies demonstrate variable capacity of the PPxPxY motifs from these proteins to bind VP30, define PxPPPPxY as an optimal binding motif, and identify the fifth proline and the tyrosine as most critical for interaction. Competition binding and hydrogen-deuterium exchange mass spectrometry studies demonstrate that each protein binds a similar interface on VP30. VP30 therefore presents a novel proline recognition domain that is targeted by multiple host proteins to modulate viral transcription.
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Affiliation(s)
- Jyoti Batra
- J. David Gladstone Institutes, San Francisco, CA, USA.,Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA, USA.,Quantitative Biosciences Institute, University of California, San Francisco, CA, USA
| | - Hiroyuki Mori
- Department of Microbiology, NEIDL, Boston University School of Medicine, Boston, MA, USA
| | - Gabriel I Small
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA.,John T. Milliken Department of Medicine, Division of Infectious Diseases, Washington University School of Medicine, St. Louis, MO, USA
| | - Manu Anantpadma
- Department of Microbiology, NEIDL, Boston University School of Medicine, Boston, MA, USA
| | - Olena Shtanko
- Host-Pathogen Interactions, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Nawneet Mishra
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Mengru Zhang
- Department of Chemistry, Washington University School of Medicine, St. Louis, MO, USA
| | - Dandan Liu
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Caroline G Williams
- Center for Microbial Pathogenesis, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, USA
| | - Nadine Biedenkopf
- Institute of Virology, Philipps University of Marburg, Marburg, Germany
| | - Stephan Becker
- Institute of Virology, Philipps University of Marburg, Marburg, Germany
| | - Michael L Gross
- Department of Chemistry, Washington University School of Medicine, St. Louis, MO, USA
| | - Daisy W Leung
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA.,John T. Milliken Department of Medicine, Division of Infectious Diseases, Washington University School of Medicine, St. Louis, MO, USA
| | - Robert A Davey
- Department of Microbiology, NEIDL, Boston University School of Medicine, Boston, MA, USA
| | - Gaya K Amarasinghe
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - Nevan J Krogan
- J. David Gladstone Institutes, San Francisco, CA, USA.,Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA, USA.,Quantitative Biosciences Institute, University of California, San Francisco, CA, USA
| | - Christopher F Basler
- Center for Microbial Pathogenesis, Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, USA
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44
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Remdesivir inhibits the polymerases of the novel filoviruses Lloviu and Bombali virus. Antiviral Res 2021; 192:105120. [PMID: 34126139 DOI: 10.1016/j.antiviral.2021.105120] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 05/21/2021] [Accepted: 06/10/2021] [Indexed: 01/18/2023]
Abstract
In recent years, a number of novel filoviruses (e.g. Lloviu virus (LLOV) and Bombali virus (BOMV)) have been discovered. While antibody-based therapeutics have recently been approved for treatment of infections with the filovirus Ebola virus (EBOV), no treatment options for novel filoviruses currently exist. Further, the development of antivirals against them is complicated by the fact that only sequence information, but no actual virus isolates, are available. To address this issue, we developed a reverse genetics-based minigenome system for BOMV, which allows us to assess the activity of the BOMV polymerase. Together with similar systems that we have developed for other filoviruses in the past (i.e. LLOV and Reston virus (RESTV)), we then assessed the efficiency of remdesivir, a known inhibitor of the EBOV polymerase that has recently been tested in a clinical trial for efficacy against Ebola disease. We show that remdesivir is indeed also active against the polymerases of BOMV, LLOV, and RESTV, with comparable IC50 values to its activity against EBOV. This suggests that treatment with remdesivir might represent a viable option in case of infections with novel filoviruses.
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Abstract
Ebola virus is among the most dangerous viral pathogens, with a case fatality rate of up to 90%. Since 2013, the two largest and most complex Ebola outbreaks in West Africa have revealed the lack of investigation on this notorious virus. Ebola virus (EBOV) is a highly pathogenic negative-stranded RNA virus that has caused several deadly endemics in the past decades. EBOV reverse genetics systems are available for studying live viruses under biosafety level 4 (BSL-4) or subviral particles under BSL-2 conditions. However, these systems all require cotransfection of multiple plasmids expressing viral genome and viral proteins essential for EBOV replication, which is technically challenging and unable to naturally mimic virus propagation using the subviral particle. Here, we established a new EBOV reverse genetics system only requiring transfection of a single viral RNA genome into an engineered cell line that stably expresses viral nucleoprotein (NP), viral protein 35 (VP35), VP30, and large (L) proteins and has been fine-tuned for its superior permissiveness for EBOV replication. Using this system, subviral particles expressing viral VP40, glycoprotein (GP), and VP24 could be produced and continuously propagated and eventually infect the entire cell population. We demonstrated the authentic response of the subviral system to antivirals and uncovered that the VP35 amount is critical for optimal virus replication. Furthermore, we showed that fully infectious virions can be efficiently rescued by delivering the full-length EBOV genome into the same supporting cell, and the efficiency is not affected by genome polarity or virus variant specificity. In summary, our work provides a new tool for studying EBOV under different biosafety levels. IMPORTANCE Ebola virus is among the most dangerous viral pathogens, with a case fatality rate of up to 90%. Since 2013, the two largest and most complex Ebola outbreaks in Africa have revealed the lack of investigation on this notorious virus. A reverse genetics system is an important tool for studying viruses by producing mutant viruses or generating safer and convenient model systems. Here, we developed an EBOV life cycle modeling system in which subviral particles can spontaneously propagate in cell culture. In addition, this system can be employed to rescue infectious virions of homologous or heterologous EBOV isolates using either sense or antisense viral RNA genomes. In summary, we developed a new tool for EBOV research.
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Braun MR, Noton SL, Blanchard EL, Shareef A, Santangelo PJ, Johnson WE, Fearns R. Respiratory syncytial virus M2-1 protein associates non-specifically with viral messenger RNA and with specific cellular messenger RNA transcripts. PLoS Pathog 2021; 17:e1009589. [PMID: 34003848 PMCID: PMC8162694 DOI: 10.1371/journal.ppat.1009589] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 05/28/2021] [Accepted: 04/26/2021] [Indexed: 11/18/2022] Open
Abstract
Respiratory syncytial virus (RSV) is a major cause of respiratory disease in infants and the elderly. RSV is a non-segmented negative strand RNA virus. The viral M2-1 protein plays a key role in viral transcription, serving as an elongation factor to enable synthesis of full-length mRNAs. M2-1 contains an unusual CCCH zinc-finger motif that is conserved in the related human metapneumovirus M2-1 protein and filovirus VP30 proteins. Previous biochemical studies have suggested that RSV M2-1 might bind to specific virus RNA sequences, such as the transcription gene end signals or poly A tails, but there was no clear consensus on what RSV sequences it binds. To determine if M2-1 binds to specific RSV RNA sequences during infection, we mapped points of M2-1:RNA interactions in RSV-infected cells at 8 and 18 hours post infection using crosslinking immunoprecipitation with RNA sequencing (CLIP-Seq). This analysis revealed that M2-1 interacts specifically with positive sense RSV RNA, but not negative sense genome RNA. It also showed that M2-1 makes contacts along the length of each viral mRNA, indicating that M2-1 functions as a component of the transcriptase complex, transiently associating with nascent mRNA being extruded from the polymerase. In addition, we found that M2-1 binds specific cellular mRNAs. In contrast to the situation with RSV mRNA, M2-1 binds discrete sites within cellular mRNAs, with a preference for A/U rich sequences. These results suggest that in addition to its previously described role in transcription elongation, M2-1 might have an additional role involving cellular RNA interactions.
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Affiliation(s)
- Molly R. Braun
- Department of Microbiology, Boston University School of Medicine; National Emerging Infectious Diseases Laboratories, Boston University, Boston, Massachusetts, United States of America
| | - Sarah L. Noton
- Department of Microbiology, Boston University School of Medicine; National Emerging Infectious Diseases Laboratories, Boston University, Boston, Massachusetts, United States of America
| | - Emmeline L. Blanchard
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, United States of America
| | - Afzaal Shareef
- Department of Microbiology, Boston University School of Medicine; National Emerging Infectious Diseases Laboratories, Boston University, Boston, Massachusetts, United States of America
| | - Philip J. Santangelo
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, United States of America
| | - W. Evan Johnson
- Division of Computational Biomedicine and Bioinformatics Program and Department of Biostatistics, Boston University, Boston, Massachusetts, United States of America
| | - Rachel Fearns
- Department of Microbiology, Boston University School of Medicine; National Emerging Infectious Diseases Laboratories, Boston University, Boston, Massachusetts, United States of America
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Hansen F, Feldmann H, Jarvis MA. Targeting Ebola virus replication through pharmaceutical intervention. Expert Opin Investig Drugs 2021; 30:201-226. [PMID: 33593215 DOI: 10.1080/13543784.2021.1881061] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Introduction. The consistent emergence/reemergence of filoviruses into a world that previously lacked an approved pharmaceutical intervention parallels an experience repeatedly played-out for most other emerging pathogenic zoonotic viruses. Investment to preemptively develop effective and low-cost prophylactic and therapeutic interventions against viruses that have high potential for emergence and societal impact should be a priority.Areas covered. Candidate drugs can be characterized into those that interfere with cellular processes required for Ebola virus (EBOV) replication (host-directed), and those that directly target virally encoded functions (direct-acting). We discuss strategies to identify pharmaceutical interventions for EBOV infections. PubMed/Web of Science databases were searched to establish a detailed catalog of these interventions.Expert opinion. Many drug candidates show promising in vitro inhibitory activity, but experience with EBOV shows the general lack of translation to in vivo efficacy for host-directed repurposed drugs. Better translation is seen for direct-acting antivirals, in particular monoclonal antibodies. The FDA-approved monoclonal antibody treatment, Inmazeb™ is a success story that could be improved in terms of impact on EBOV-associated disease and mortality, possibly by combination with other direct-acting agents targeting distinct aspects of the viral replication cycle. Costs need to be addressed given EBOV emergence primarily in under-resourced countries.
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Affiliation(s)
- Frederick Hansen
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Heinz Feldmann
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Michael A Jarvis
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA.,School of Biomedical Sciences, University of Plymouth, Plymouth, Devon, UK.,The Vaccine Group, Ltd, Plymouth, Devon, UK
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Bach S, Demper JC, Grünweller A, Becker S, Biedenkopf N, Hartmann RK. Regulation of VP30-Dependent Transcription by RNA Sequence and Structure in the Genomic Ebola Virus Promoter. J Virol 2021; 95:JVI.02215-20. [PMID: 33268520 PMCID: PMC8092829 DOI: 10.1128/jvi.02215-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 11/22/2020] [Indexed: 01/16/2023] Open
Abstract
Viral transcription and replication of Ebola virus (EBOV) is balanced by transcription factor VP30, an RNA binding protein. An RNA hairpin at the transcription start site (TSS) of the first gene (NP hairpin) in the 3'-leader promoter is thought to mediate the VP30 dependency of transcription. Here, we investigated the constraints of VP30 dependency using a series of monocistronic minigenomes with sequence, structure and length deviations from the native NP hairpin. Hairpin stabilizations decreased while destabilizations increased transcription in the absence of VP30, but in all cases, transcription activity was higher in the presence versus absence of VP30. This also pertains to a mutant that is unable to form any RNA secondary structure at the TSS, demonstrating that the activity of VP30 is not simply determined by the capacity to form a hairpin structure at the TSS. Introduction of continuous 3'-UN5 hexamer phasing between promoter elements PE1 and PE2 by a single point mutation in the NP hairpin boosted VP30-independent transcription. Moreover, this point mutation, but also hairpin stabilizations, impaired the relative increase of replication in the absence of VP30. Our results suggest that the native NP hairpin is optimized for tight regulation by VP30 while avoiding an extent of hairpin stability that impairs viral transcription, as well as for enabling the switch from transcription to replication when VP30 is not part of the polymerase complex.IMPORTANCE A detailed understanding is lacking how the Ebola virus (EBOV) protein VP30 regulates activity of the viral polymerase complex. Here, we studied how RNA sequence, length and structure at the transcription start site (TSS) in the 3'-leader promoter influence the impact of VP30 on viral polymerase activity. We found that hairpin stabilizations tighten the VP30 dependency of transcription but reduce transcription efficiency and attenuate the switch to replication in the absence of VP30. Upon hairpin destabilization, VP30-independent transcription - already weakly detectable at the native promoter - increases, but never reaches the same extent as in the presence of VP30. We conclude that the native hairpin structure involving the TSS (i) establishes an optimal balance between efficient transcription and tight regulation by VP30, (ii) is linked to hexamer phasing in the promoter, and (iii) favors the switch to replication when VP30 is absent.
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Affiliation(s)
- Simone Bach
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marbacher Weg 6, 35037 Marburg, Germany
| | - Jana-Christin Demper
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marbacher Weg 6, 35037 Marburg, Germany
| | - Arnold Grünweller
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marbacher Weg 6, 35037 Marburg, Germany
| | - Stephan Becker
- Institut für Virologie, Philipps-Universität Marburg, Hans-Meerwein-Str. 2, 35043 Marburg
| | - Nadine Biedenkopf
- Institut für Virologie, Philipps-Universität Marburg, Hans-Meerwein-Str. 2, 35043 Marburg
| | - Roland K Hartmann
- Institut für Pharmazeutische Chemie, Philipps-Universität Marburg, Marbacher Weg 6, 35037 Marburg, Germany
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Misasi J, Sullivan NJ. Immunotherapeutic strategies to target vulnerabilities in the Ebolavirus glycoprotein. Immunity 2021; 54:412-436. [PMID: 33691133 DOI: 10.1016/j.immuni.2021.01.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 01/15/2021] [Accepted: 01/20/2021] [Indexed: 12/18/2022]
Abstract
The 2014 Ebola virus disease (EVD) outbreak in West Africa and the subsequent outbreaks of 2018-2020 in Equator and North Kivu provinces of the Democratic Republic of the Congo illustrate the public health challenges of emerging and reemerging viruses. EVD has a high case fatality rate with a rapidly progressing syndrome of fever, rash, vomiting, diarrhea, and bleeding diathesis. Recently, two monoclonal-antibody-based therapies received United States Food and Drug Administration (FDA) approval, and there are several other passive immunotherapies that hold promise as therapeutics against other species of Ebolavirus. Here, we review concepts needed to understand mechanisms of action, present an expanded schema to define additional sites of vulnerability on the viral glycoprotein, and review current antibody-based therapeutics. The concepts described are used to gain insights into the key characteristics that represent functional targets for immunotherapies against Zaire Ebolavirus and other emerging viruses within the Ebolavirus genus.
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Affiliation(s)
- John Misasi
- National Institutes of Health, National Institute of Allergy and Infectious Diseases, Vaccine Research Center, 40 Convent Drive, Bethesda, MD 20892, USA
| | - Nancy J Sullivan
- National Institutes of Health, National Institute of Allergy and Infectious Diseases, Vaccine Research Center, 40 Convent Drive, Bethesda, MD 20892, USA.
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Transcriptional Analysis of Lymphoid Tissues from Infected Nonhuman Primates Reveals the Basis for Attenuation and Immunogenicity of an Ebola Virus Encoding a Mutant VP35 Protein. J Virol 2021; 95:JVI.01995-20. [PMID: 33408171 DOI: 10.1128/jvi.01995-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 12/16/2020] [Indexed: 12/14/2022] Open
Abstract
Infection with Zaire ebolavirus (EBOV), a member of the Filoviridae family, causes a disease characterized by high levels of viremia, aberrant inflammation, coagulopathy, and lymphopenia. EBOV initially replicates in lymphoid tissues and disseminates via dendritic cells (DCs) and monocytes to liver, spleen, adrenal gland, and other secondary organs. EBOV protein VP35 is a critical immune evasion factor that inhibits type I interferon signaling and DC maturation. Nonhuman primates (NHPs) immunized with a high dose (5 × 105 PFU) of recombinant EBOV containing a mutated VP35 (VP35m) are protected from challenge with wild-type EBOV (wtEBOV). This protection is accompanied by a transcriptional response in the peripheral blood reflecting a regulated innate immune response and a robust induction of adaptive immune genes. However, the host transcriptional response to VP35m in lymphoid tissues has not been evaluated. Therefore, we conducted a transcriptional analysis of axillary and inguinal lymph nodes and spleen tissues of NHPs infected with a low dose (2 × 104 PFU) of VP35m and then back-challenged with a lethal dose of wtEBOV. VP35m induced early transcriptional responses in lymphoid tissues that are distinct from those observed in wtEBOV challenge. Specifically, we detected robust antiviral innate and adaptive responses and fewer transcriptional changes in genes with roles in angiogenesis, apoptosis, and inflammation. Two of three macaques survived wtEBOV back-challenge, with only the nonsurvivor displaying a transcriptional response reflecting Ebola virus disease. These data suggest that VP35 is a key modulator of early host responses in lymphoid tissues, thereby regulating disease progression and severity following EBOV challenge.IMPORTANCE Zaire Ebola virus (EBOV) infection causes a severe and often fatal disease characterized by inflammation, coagulation defects, and organ failure driven by a defective host immune response. Lymphoid tissues are key sites of EBOV pathogenesis and the generation of an effective immune response to infection. A recent study demonstrated that infection with an EBOV encoding a mutant VP35, a viral protein that antagonizes host immunity, can protect nonhuman primates (NHPs) against lethal EBOV challenge. However, no studies have examined the response to this mutant EBOV in lymphoid tissues. Here, we characterize gene expression in lymphoid tissues from NHPs challenged with the mutant EBOV and subsequently with wild-type EBOV to identify signatures of a protective host response. Our findings are critical for elucidating viral pathogenesis, mechanisms of host antagonism, and the role of lymphoid organs in protective responses to EBOV to improve the development of antivirals and vaccines against EBOV.
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