1
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Moreno S, Lorenzo G, López-Valiñas Á, de la Losa N, Alonso C, Charro E, Núñez JI, Sánchez-Cordón PJ, Borrego B, Brun A. Safety and Efficacy upon Infection in Sheep with Rift Valley Fever Virus ZH548-rA2, a Triple Mutant Rescued Virus. Viruses 2024; 16:87. [PMID: 38257787 PMCID: PMC10819402 DOI: 10.3390/v16010087] [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: 12/20/2023] [Revised: 12/29/2023] [Accepted: 01/02/2024] [Indexed: 01/24/2024] Open
Abstract
The introduction of three single nucleotide mutations into the genome of the virulent RVFV ZH548 strain allows for the rescue of a fully attenuated virus in mice (ZH548-rA2). These mutations are located in the viral genes encoding the RdRp and the non-structural protein NSs. This paper shows the results obtained after the subcutaneous inoculation of ZH548-rA2 in adult sheep and the subsequent challenge with the parental virus (ZH548-rC1). Inoculation with the ZH548-rA2 virus caused no detectable clinical or pathological effect in sheep, whereas inoculation of the parental rC1 virus caused lesions compatible with viral infection characterised by the presence of scattered hepatic necrosis. Viral infection was confirmed via immunohistochemistry, with hepatocytes within the necrotic foci appearing as the main cells immunolabelled against viral antigen. Furthermore, the inoculation of sheep with the rA2 virus prevented the liver damage expected after rC1 virus inoculation, suggesting a protective efficacy in sheep which correlated with the induction of both humoral and cell-mediated immune responses.
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Affiliation(s)
- Sandra Moreno
- Centro de Investigación en Sanidad Animal (CISA), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Consejo Superior de Investigaciones Científicas (INIA-CSIC), Valdeolmos, 28130 Madrid, Spain; (S.M.); (G.L.); (P.J.S.-C.)
| | - Gema Lorenzo
- Centro de Investigación en Sanidad Animal (CISA), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Consejo Superior de Investigaciones Científicas (INIA-CSIC), Valdeolmos, 28130 Madrid, Spain; (S.M.); (G.L.); (P.J.S.-C.)
| | - Álvaro López-Valiñas
- Centre de Recerca en Sanitat Animal (CReSA), Institut de Recerca i Tecnologia Agroalimentàries (IRTA), Bellaterra, 08193 Barcelona, Spain (J.I.N.)
| | - Nuria de la Losa
- Centro de Investigación en Sanidad Animal (CISA), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Consejo Superior de Investigaciones Científicas (INIA-CSIC), Valdeolmos, 28130 Madrid, Spain; (S.M.); (G.L.); (P.J.S.-C.)
| | - Celia Alonso
- Centro de Investigación en Sanidad Animal (CISA), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Consejo Superior de Investigaciones Científicas (INIA-CSIC), Valdeolmos, 28130 Madrid, Spain; (S.M.); (G.L.); (P.J.S.-C.)
| | - Elena Charro
- Centro de Investigación en Sanidad Animal (CISA), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Consejo Superior de Investigaciones Científicas (INIA-CSIC), Valdeolmos, 28130 Madrid, Spain; (S.M.); (G.L.); (P.J.S.-C.)
| | - José I. Núñez
- Centre de Recerca en Sanitat Animal (CReSA), Institut de Recerca i Tecnologia Agroalimentàries (IRTA), Bellaterra, 08193 Barcelona, Spain (J.I.N.)
| | - Pedro J. Sánchez-Cordón
- Centro de Investigación en Sanidad Animal (CISA), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Consejo Superior de Investigaciones Científicas (INIA-CSIC), Valdeolmos, 28130 Madrid, Spain; (S.M.); (G.L.); (P.J.S.-C.)
| | - Belén Borrego
- Centro de Investigación en Sanidad Animal (CISA), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Consejo Superior de Investigaciones Científicas (INIA-CSIC), Valdeolmos, 28130 Madrid, Spain; (S.M.); (G.L.); (P.J.S.-C.)
| | - Alejandro Brun
- Centro de Investigación en Sanidad Animal (CISA), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Consejo Superior de Investigaciones Científicas (INIA-CSIC), Valdeolmos, 28130 Madrid, Spain; (S.M.); (G.L.); (P.J.S.-C.)
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2
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Doores KJ. Humoral immunity to phlebovirus infection. Ann N Y Acad Sci 2023; 1530:23-31. [PMID: 37936483 PMCID: PMC10952791 DOI: 10.1111/nyas.15080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
Phleboviruses are zoonotic pathogens found in parts of Africa, Asia, Europe, and North America and cause disease symptoms ranging from self-limiting febrile illness to severe disease, including hemorrhagic diathesis, encephalitis, and ocular pathologies. There are currently no approved preventative vaccines against phlebovirus infection or antivirals for the treatment of the disease. Here, we discuss the roles of neutralizing antibodies in phlebovirus infection, the antigenic targets present on the mature polyproteins Gn and Gc, progress in vaccine development, and the prospects of identifying conserved neutralizing epitopes across multiple phleboviruses. Further research in this area will pave the way for the rational design of pan-phlebovirus vaccines that will protect against both known phleboviruses but also newly emerging phleboviruses that may have pandemic potential.
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Affiliation(s)
- Katie J. Doores
- Department of Infectious Diseases, King's College LondonGuy's HospitalLondonUK
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3
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Du S, Peng R, Xu W, Qu X, Wang Y, Wang J, Li L, Tian M, Guan Y, Wang J, Wang G, Li H, Deng L, Shi X, Ma Y, Liu F, Sun M, Wei Z, Jin N, Liu W, Qi J, Liu Q, Liao M, Li C. Cryo-EM structure of severe fever with thrombocytopenia syndrome virus. Nat Commun 2023; 14:6333. [PMID: 37816705 PMCID: PMC10564799 DOI: 10.1038/s41467-023-41804-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 09/19/2023] [Indexed: 10/12/2023] Open
Abstract
The severe fever with thrombocytopenia syndrome virus (SFTSV) is a tick-borne human-infecting bunyavirus, which utilizes two envelope glycoproteins, Gn and Gc, to enter host cells. However, the structure and organization of these glycoproteins on virion surface are not yet known. Here we describe the structure of SFTSV determined by single particle reconstruction, which allows mechanistic insights into bunyavirus assembly at near-atomic resolution. The SFTSV Gn and Gc proteins exist as heterodimers and further assemble into pentameric and hexameric peplomers, shielding the Gc fusion loops by both intra- and inter-heterodimer interactions. Individual peplomers are associated mainly through the ectodomains, in which the highly conserved glycans on N914 of Gc play a crucial role. This elaborate assembly stabilizes Gc in the metastable prefusion conformation and creates some cryptic epitopes that are only accessible in the intermediate states during virus entry. These findings provide an important basis for developing vaccines and therapeutic drugs.
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Affiliation(s)
- Shouwen Du
- Key Laboratory of Livestock Disease Prevention of Guangdong Province, Scientific Observation and Experiment Station of Veterinary Drugs and Diagnostic Techniques of Guangdong Province, Ministry of Agriculture and Rural Affairs, Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou, China
- The First Affiliated Hospital (Shenzhen People's Hospital), Southern University of Science and Technology, Shenzhen, China
- Department of Infectious Diseases and Center for Infectious Diseases and Pathogen Biology, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, The First Hospital of Jilin University, Changchun, China
| | - Ruchao Peng
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Wang Xu
- Research Unit of Key Technologies for Prevention and Control of Virus Zoonoses, Chinese Academy of Medical Sciences, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China
| | - Xiaoyun Qu
- Key Laboratory of Livestock Disease Prevention of Guangdong Province, Scientific Observation and Experiment Station of Veterinary Drugs and Diagnostic Techniques of Guangdong Province, Ministry of Agriculture and Rural Affairs, Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou, China
- Key Laboratory of Zoonosis of Ministry of Agriculture and Rural Affairs, South China Agricultural University, Guangzhou, China
| | - Yuhang Wang
- The First Affiliated Hospital (Shenzhen People's Hospital), Southern University of Science and Technology, Shenzhen, China
| | - Jiamin Wang
- Research Unit of Key Technologies for Prevention and Control of Virus Zoonoses, Chinese Academy of Medical Sciences, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China
| | - Letian Li
- Research Unit of Key Technologies for Prevention and Control of Virus Zoonoses, Chinese Academy of Medical Sciences, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China
| | - Mingyao Tian
- Research Unit of Key Technologies for Prevention and Control of Virus Zoonoses, Chinese Academy of Medical Sciences, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China
| | - Yudong Guan
- The First Affiliated Hospital (Shenzhen People's Hospital), Southern University of Science and Technology, Shenzhen, China
| | - Jigang Wang
- The First Affiliated Hospital (Shenzhen People's Hospital), Southern University of Science and Technology, Shenzhen, China
| | - Guoqing Wang
- Department of Infectious Diseases and Center for Infectious Diseases and Pathogen Biology, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, The First Hospital of Jilin University, Changchun, China
| | - Hao Li
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Lingcong Deng
- Research Unit of Key Technologies for Prevention and Control of Virus Zoonoses, Chinese Academy of Medical Sciences, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China
| | - Xiaoshuang Shi
- Research Unit of Key Technologies for Prevention and Control of Virus Zoonoses, Chinese Academy of Medical Sciences, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China
| | - Yidan Ma
- Research Unit of Key Technologies for Prevention and Control of Virus Zoonoses, Chinese Academy of Medical Sciences, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China
| | - Fengting Liu
- The First Affiliated Hospital (Shenzhen People's Hospital), Southern University of Science and Technology, Shenzhen, China
| | - Minhua Sun
- Key Laboratory of Livestock Disease Prevention of Guangdong Province, Scientific Observation and Experiment Station of Veterinary Drugs and Diagnostic Techniques of Guangdong Province, Ministry of Agriculture and Rural Affairs, Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou, China
| | - Zhengkai Wei
- Key Laboratory of Livestock Disease Prevention of Guangdong Province, Scientific Observation and Experiment Station of Veterinary Drugs and Diagnostic Techniques of Guangdong Province, Ministry of Agriculture and Rural Affairs, Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou, China
| | - Ningyi Jin
- Research Unit of Key Technologies for Prevention and Control of Virus Zoonoses, Chinese Academy of Medical Sciences, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China
| | - Wei Liu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.
| | - Jianxun Qi
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
- Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China.
| | - Quan Liu
- Key Laboratory of Livestock Disease Prevention of Guangdong Province, Scientific Observation and Experiment Station of Veterinary Drugs and Diagnostic Techniques of Guangdong Province, Ministry of Agriculture and Rural Affairs, Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou, China.
- Department of Infectious Diseases and Center for Infectious Diseases and Pathogen Biology, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, The First Hospital of Jilin University, Changchun, China.
- Guangdong Key Laboratory of Animal Conservation and Resource Utilization, Institute of Zoology, Guangdong Academy of Sciences, Foshan University, Foshan, China.
| | - Ming Liao
- Key Laboratory of Livestock Disease Prevention of Guangdong Province, Scientific Observation and Experiment Station of Veterinary Drugs and Diagnostic Techniques of Guangdong Province, Ministry of Agriculture and Rural Affairs, Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou, China.
- Key Laboratory of Zoonosis of Ministry of Agriculture and Rural Affairs, South China Agricultural University, Guangzhou, China.
| | - Chang Li
- Department of Infectious Diseases and Center for Infectious Diseases and Pathogen Biology, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, The First Hospital of Jilin University, Changchun, China.
- Research Unit of Key Technologies for Prevention and Control of Virus Zoonoses, Chinese Academy of Medical Sciences, Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China.
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4
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Nair N, Osterhaus ADME, Rimmelzwaan GF, Prajeeth CK. Rift Valley Fever Virus-Infection, Pathogenesis and Host Immune Responses. Pathogens 2023; 12:1174. [PMID: 37764982 PMCID: PMC10535968 DOI: 10.3390/pathogens12091174] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 09/09/2023] [Accepted: 09/14/2023] [Indexed: 09/29/2023] Open
Abstract
Rift Valley Fever Virus is a mosquito-borne phlebovirus causing febrile or haemorrhagic illness in ruminants and humans. The virus can prevent the induction of the antiviral interferon response through its NSs proteins. Mutations in the NSs gene may allow the induction of innate proinflammatory immune responses and lead to attenuation of the virus. Upon infection, virus-specific antibodies and T cells are induced that may afford protection against subsequent infections. Thus, all arms of the adaptive immune system contribute to prevention of disease progression. These findings will aid the design of vaccines using the currently available platforms. Vaccine candidates have shown promise in safety and efficacy trials in susceptible animal species and these may contribute to the control of RVFV infections and prevention of disease progression in humans and ruminants.
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5
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Chapman NS, Hulswit RJG, Westover JLB, Stass R, Paesen GC, Binshtein E, Reidy JX, Engdahl TB, Handal LS, Flores A, Gowen BB, Bowden TA, Crowe JE. Multifunctional human monoclonal antibody combination mediates protection against Rift Valley fever virus at low doses. Nat Commun 2023; 14:5650. [PMID: 37704627 PMCID: PMC10499838 DOI: 10.1038/s41467-023-41171-3] [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: 09/10/2022] [Accepted: 08/22/2023] [Indexed: 09/15/2023] Open
Abstract
The zoonotic Rift Valley fever virus (RVFV) can cause severe disease in humans and has pandemic potential, yet no approved vaccine or therapy exists. Here we describe a dual-mechanism human monoclonal antibody (mAb) combination against RVFV that is effective at minimal doses in a lethal mouse model of infection. We structurally analyze and characterize the binding mode of a prototypical potent Gn domain-A-binding antibody that blocks attachment and of an antibody that inhibits infection by abrogating the fusion process as previously determined. Surprisingly, the Gn domain-A antibody does not directly block RVFV Gn interaction with the host receptor low density lipoprotein receptor-related protein 1 (LRP1) as determined by a competitive assay. This study identifies a rationally designed combination of human mAbs deserving of future investigation for use in humans against RVFV infection. Using a two-pronged mechanistic approach, we demonstrate the potent efficacy of a rationally designed combination mAb therapeutic.
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Affiliation(s)
- Nathaniel S Chapman
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Ruben J G Hulswit
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN, UK
| | - Jonna L B Westover
- Department of Animal, Dairy and Veterinary Sciences, Utah State University, Logan, UT, 84322, USA
| | - Robert Stass
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN, UK
| | - Guido C Paesen
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN, UK
| | - Elad Binshtein
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Joseph X Reidy
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Taylor B Engdahl
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Laura S Handal
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Alejandra Flores
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Brian B Gowen
- Department of Animal, Dairy and Veterinary Sciences, Utah State University, Logan, UT, 84322, USA
| | - Thomas A Bowden
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN, UK
| | - James E Crowe
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA.
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, 37232, USA.
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, 37232, USA.
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6
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Koch J, Xin Q, Obr M, Schäfer A, Rolfs N, Anagho HA, Kudulyte A, Woltereck L, Kummer S, Campos J, Uckeley ZM, Bell-Sakyi L, Kräusslich HG, Schur FKM, Acuna C, Lozach PY. The phenuivirus Toscana virus makes an atypical use of vacuolar acidity to enter host cells. PLoS Pathog 2023; 19:e1011562. [PMID: 37578957 PMCID: PMC10449198 DOI: 10.1371/journal.ppat.1011562] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 08/24/2023] [Accepted: 07/17/2023] [Indexed: 08/16/2023] Open
Abstract
Toscana virus is a major cause of arboviral disease in humans in the Mediterranean basin during summer. However, early virus-host cell interactions and entry mechanisms remain poorly characterized. Investigating iPSC-derived human neurons and cell lines, we found that virus binding to the cell surface was specific, and 50% of bound virions were endocytosed within 10 min. Virions entered Rab5a+ early endosomes and, subsequently, Rab7a+ and LAMP-1+ late endosomal compartments. Penetration required intact late endosomes and occurred within 30 min following internalization. Virus entry relied on vacuolar acidification, with an optimal pH for viral membrane fusion at pH 5.5. The pH threshold increased to 5.8 with longer pre-exposure of virions to the slightly acidic pH in early endosomes. Strikingly, the particles remained infectious after entering late endosomes with a pH below the fusion threshold. Overall, our study establishes Toscana virus as a late-penetrating virus and reveals an atypical use of vacuolar acidity by this virus to enter host cells.
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Affiliation(s)
- Jana Koch
- Center for Integrative Infectious Diseases Research (CIID), University Hospital Heidelberg, Heidelberg, Germany
- CellNetworks–Cluster of Excellence, Heidelberg, Germany
- Univ. Lyon, INRAE, EPHE, IVPC, Lyon, France
| | - Qilin Xin
- Univ. Lyon, INRAE, EPHE, IVPC, Lyon, France
| | - Martin Obr
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Alicia Schäfer
- Center for Integrative Infectious Diseases Research (CIID), University Hospital Heidelberg, Heidelberg, Germany
- CellNetworks–Cluster of Excellence, Heidelberg, Germany
| | - Nina Rolfs
- Center for Integrative Infectious Diseases Research (CIID), University Hospital Heidelberg, Heidelberg, Germany
- CellNetworks–Cluster of Excellence, Heidelberg, Germany
| | - Holda A. Anagho
- Center for Integrative Infectious Diseases Research (CIID), University Hospital Heidelberg, Heidelberg, Germany
- CellNetworks–Cluster of Excellence, Heidelberg, Germany
| | - Aiste Kudulyte
- Center for Integrative Infectious Diseases Research (CIID), University Hospital Heidelberg, Heidelberg, Germany
- CellNetworks–Cluster of Excellence, Heidelberg, Germany
| | - Lea Woltereck
- Center for Integrative Infectious Diseases Research (CIID), University Hospital Heidelberg, Heidelberg, Germany
- CellNetworks–Cluster of Excellence, Heidelberg, Germany
| | - Susann Kummer
- Center for Integrative Infectious Diseases Research (CIID), University Hospital Heidelberg, Heidelberg, Germany
| | - Joaquin Campos
- Chica and Heinz Schaller Research Group, Institute of Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - Zina M. Uckeley
- Center for Integrative Infectious Diseases Research (CIID), University Hospital Heidelberg, Heidelberg, Germany
- CellNetworks–Cluster of Excellence, Heidelberg, Germany
| | - Lesley Bell-Sakyi
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, United-Kingdom
| | - Hans-Georg Kräusslich
- Center for Integrative Infectious Diseases Research (CIID), University Hospital Heidelberg, Heidelberg, Germany
| | - Florian KM. Schur
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Claudio Acuna
- Chica and Heinz Schaller Research Group, Institute of Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - Pierre-Yves Lozach
- Center for Integrative Infectious Diseases Research (CIID), University Hospital Heidelberg, Heidelberg, Germany
- CellNetworks–Cluster of Excellence, Heidelberg, Germany
- Univ. Lyon, INRAE, EPHE, IVPC, Lyon, France
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7
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New Isolation of Ponticelli III Virus ( Bunyavirales: Phenuiviridae) in Emilia-Romagna Region, Italy. Viruses 2023; 15:v15020422. [PMID: 36851636 PMCID: PMC9964127 DOI: 10.3390/v15020422] [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: 10/13/2022] [Revised: 01/16/2023] [Accepted: 01/29/2023] [Indexed: 02/05/2023] Open
Abstract
The number of newly described sandfly-borne phleboviruses has been steadily growing in recent years. Some phleboviruses are human pathogens, but their health relevance is largely uncharacterized. We aimed to investigate the circulation of these viruses in the Emilia-Romagna region where several have already been described. A total of 482 sandflies were collected in a site in Reggio Emilia in 2019 and 2020. Sandflies collected in 2020 were grouped in 21 pools with a maximum of 25 sandflies per pool, submitted to real time PCR, and isolated in Vero cell culture. Complete genome sequencing showed the isolation of a strain of a Ponticelli III virus. This virus, which belongs to the species Adana phlebovirus, differed in the M segment from the Ponticelli I and Ponticelli II viruses. Analysis performed on the genomic segments of the newly isolated virus compared with other phleboviruses highlighted a strong purifying selection in the L segments, and different substitution saturation, highest in the M segments. Future research should address the ecological processes driving the occurrence of these novel phleboviruses and their possible impact on public health.
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8
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Hao M, Bian T, Fu G, Chen Y, Fang T, Zhao C, Liu S, Yu C, Li J, Chen W. An adenovirus-vectored RVF vaccine confers complete protection against lethal RVFV challenge in A129 mice. Front Microbiol 2023; 14:1114226. [PMID: 36925463 PMCID: PMC10011166 DOI: 10.3389/fmicb.2023.1114226] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 02/10/2023] [Indexed: 03/08/2023] Open
Abstract
Instruction: Rift valley fever virus (RVFV) is a mosquito-transmitted bunyavirus that causes severe disease in animals and humans. Nevertheless, there are no vaccines applied to prevent RVFV infection for human at present. Therefore, it is necessary to develop a safe and effective RVFV vaccine. Methods: We generated Ad5-GnGcopt, a replication-deficient recombinant Ad5 vector (human adenovirus serotype 5) expressing codon-optimized RVFV glycoproteins Gn and Gc, and evaluated its immunogenicity and protective efficacy in mice. Results and Discussion: Intramuscular immunization of Ad5-GnGcopt in mice induces strong and durable antibody production and robust cellular immune responses. Additionally, a single vaccination with Ad5-GnGcopt vaccination can completely protect interferon-α/β receptor-deficient A129 mice from lethal RVFV infection. Our work indicates that Ad5-GnGcopt might represent a potential vaccine candidate against RVFV. However, further research is needed, first to confirm its efficacy in a natural animal host, and ultimately escalate as a potential vaccine candidate for humans.
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Affiliation(s)
- Meng Hao
- Vaccine and Antibody Engineer Laboratory, Beijing Institute of Biotechnology, Beijing, China
| | - Ting Bian
- Vaccine and Antibody Engineer Laboratory, Beijing Institute of Biotechnology, Beijing, China
| | - Guangcheng Fu
- Vaccine and Antibody Engineer Laboratory, Beijing Institute of Biotechnology, Beijing, China
| | - Yi Chen
- Vaccine and Antibody Engineer Laboratory, Beijing Institute of Biotechnology, Beijing, China
| | - Ting Fang
- Vaccine and Antibody Engineer Laboratory, Beijing Institute of Biotechnology, Beijing, China
| | - Chuanyi Zhao
- Vaccine and Antibody Engineer Laboratory, Beijing Institute of Biotechnology, Beijing, China
| | - Shuling Liu
- Vaccine and Antibody Engineer Laboratory, Beijing Institute of Biotechnology, Beijing, China
| | - Changming Yu
- Vaccine and Antibody Engineer Laboratory, Beijing Institute of Biotechnology, Beijing, China
| | - Jianmin Li
- Vaccine and Antibody Engineer Laboratory, Beijing Institute of Biotechnology, Beijing, China.,Frontier Biotechnology Laboratory, Zhejiang University-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou, China
| | - Wei Chen
- Vaccine and Antibody Engineer Laboratory, Beijing Institute of Biotechnology, Beijing, China
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9
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Bracci N, de la Fuente C, Saleem S, Pinkham C, Narayanan A, García-Sastre A, Balaraman V, Richt JA, Wilson W, Kehn-Hall K. Rift Valley fever virus Gn V5-epitope tagged virus enables identification of UBR4 as a Gn interacting protein that facilitates Rift Valley fever virus production. Virology 2022; 567:65-76. [PMID: 35032865 PMCID: PMC8877469 DOI: 10.1016/j.virol.2021.12.010] [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: 08/04/2021] [Revised: 11/15/2021] [Accepted: 12/31/2021] [Indexed: 02/03/2023]
Abstract
Rift Valley fever virus (RVFV) is an arbovirus that was first reported in the Rift Valley of Kenya which causes significant disease in humans and livestock. RVFV is a tri-segmented, negative-sense RNA virus consisting of a L, M, and S segments with the M segment encoding the glycoproteins Gn and Gc. Host factors that interact with Gn are largely unknown. To this end, two viruses containing an epitope tag (V5) on the Gn protein in position 105 or 229 (V5Gn105 and V5Gn229) were generated using the RVFV MP-12 vaccine strain as a backbone. The V5-tag insertion minimally impacted Gn functionality as measured by replication kinetics, Gn localization, and antibody neutralization assays. A proteomics-based approach was used to identify novel Gn-binding host proteins, including the E3 ubiquitin-protein ligase, UBR4. Depletion of UBR4 resulted in a significant decrease in RVFV titers and a reduction in viral RNA production.
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Affiliation(s)
- Nicole Bracci
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University,National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University
| | - Cynthia de la Fuente
- The National Institutes of Health, National Institute of Allergy and Infectious Diseases, DEA,National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University
| | - Sahar Saleem
- National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University
| | - Chelsea Pinkham
- National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University
| | - Aarthi Narayanan
- National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University
| | | | - Velmurugan Balaraman
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University
| | - Juergen A. Richt
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University
| | - William Wilson
- National Bio and Agro-Defense Facility, Agricultural Research Service, USDA
| | - Kylene Kehn-Hall
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University,National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University,Center for Zoonotic and Arthropod-borne Pathogens, Virginia Polytechnic Institute and State University,Corresponding Author: Kylene Kehn-Hall, Ph.D., Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Integrated Life Sciences Building, 1981 Kraft Drive, Blacksburg, VA 24060 USA,
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10
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Highly adaptive
Phenuiviridae
with biomedical importance in multiple fields. J Med Virol 2022; 94:2388-2401. [DOI: 10.1002/jmv.27618] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 12/24/2021] [Accepted: 01/21/2022] [Indexed: 11/07/2022]
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11
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Abstract
Rift Valley fever virus (RVFV) belongs to the order Bunyavirales and is the type species of genus Phlebovirus, which accounts for over 50% of family Phenuiviridae species. RVFV is mosquito-borne and causes severe diseases in both humans and livestock, and consists of three segments (S, M, L) in the genome. The L segment encodes an RNA-dependent RNA polymerase (RdRp, L protein) that is responsible for facilitating the replication and transcription of the virus. It is essential for the virus and has multiple drug targets. Here, we established an expression system and purification procedures for full-length L protein, which is composed of an endonuclease domain, RdRp domain, and cap-binding domain. A cryo-EM L protein structure was reported at 3.6 Å resolution. In this first L protein structure of genus Phlebovirus, the priming loop of RVFV L protein is distinctly different from those of other L proteins and undergoes large movements related to its replication role. Structural and biochemical analyses indicate that a single template can induce initiation of RNA synthesis, which is notably enhanced by 5' viral RNA. These findings help advance our understanding of the mechanism of RNA synthesis and provide an important basis for developing antiviral inhibitors. Importance The zoonosis RVF virus (RVFV) is one of the most serious arbovirus threats to both human and animal health. RNA-dependent RNA polymerase (RdRp) is a multifunctional enzyme catalyzing genome replication as well as viral transcription, so the RdRp is essential for studying the virus and has multiple drug targets. In our study, we report the structure of RVFV L protein at 3.6 Å resolution by cryo-EM. This is the first L protein structure of genus Phlebovirus. Strikingly, a single template can initiate RNA replication. The structure and assays provide a comprehensive and in-depth understanding of the catalytic and substrate recognition mechanism of RdRp.
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12
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Peng K, Lozach PY. Rift Valley fever virus: a new avenue of research on the biological functions of amyloids? Future Virol 2021. [DOI: 10.2217/fvl-2021-0094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Rift Valley fever is a mosquito-borne viral zoonosis that was first discovered in the Great Rift Valley, Kenya, in 1930. Rift Valley fever virus (RVFV) primarily infects domestic animals and humans, with clinical outcomes ranging from self-limiting febrile illness to acute hepatitis and encephalitis. The virus left Africa a few decades ago, and there is a risk of introduction into southern Europe and Asia. From this perspective, we introduce RVFV and focus on the capacity of its virulence factor, the nonstructural protein NSs, to form amyloid-like fibrils. Here, we discuss the implications for the NSs biological function, the ability of RVFV to evade innate immunity, and RVFV virulence and neurotoxicity.
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Affiliation(s)
- Ke Peng
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, Hubei, 430071, PR China
- University of the Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Pierre-Yves Lozach
- Cell Networks, CIID (Cluster of Excellence & Center for Integrative Infectious Disease Research), Virology, University Hospital Heidelberg, 69120, Heidelberg, Germany
- University of Lyon, INRAE, EPHE, IVPC (Infections Virales et Pathologie Comparée), 69007, Lyon, France
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13
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Ganaie SS, Schwarz MM, McMillen CM, Price DA, Feng AX, Albe JR, Wang W, Miersch S, Orvedahl A, Cole AR, Sentmanat MF, Mishra N, Boyles DA, Koenig ZT, Kujawa MR, Demers MA, Hoehl RM, Moyle AB, Wagner ND, Stubbs SH, Cardarelli L, Teyra J, McElroy A, Gross ML, Whelan SPJ, Doench J, Cui X, Brett TJ, Sidhu SS, Virgin HW, Egawa T, Leung DW, Amarasinghe GK, Hartman AL. Lrp1 is a host entry factor for Rift Valley fever virus. Cell 2021; 184:5163-5178.e24. [PMID: 34559985 DOI: 10.1016/j.cell.2021.09.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 04/29/2021] [Accepted: 09/01/2021] [Indexed: 12/26/2022]
Abstract
Rift Valley fever virus (RVFV) is a zoonotic pathogen with pandemic potential. RVFV entry is mediated by the viral glycoprotein (Gn), but host entry factors remain poorly defined. Our genome-wide CRISPR screen identified low-density lipoprotein receptor-related protein 1 (mouse Lrp1/human LRP1), heat shock protein (Grp94), and receptor-associated protein (RAP) as critical host factors for RVFV infection. RVFV Gn directly binds to specific Lrp1 clusters and is glycosylation independent. Exogenous addition of murine RAP domain 3 (mRAPD3) and anti-Lrp1 antibodies neutralizes RVFV infection in taxonomically diverse cell lines. Mice treated with mRAPD3 and infected with pathogenic RVFV are protected from disease and death. A mutant mRAPD3 that binds Lrp1 weakly failed to protect from RVFV infection. Together, these data support Lrp1 as a host entry factor for RVFV infection and define a new target to limit RVFV infections.
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Affiliation(s)
- Safder S Ganaie
- Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - Madeline M Schwarz
- Center for Vaccine Research, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Infectious Diseases and Microbiology, School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - Cynthia M McMillen
- Center for Vaccine Research, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Infectious Diseases and Microbiology, School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - David A Price
- Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - Annie X Feng
- Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - Joseph R Albe
- Center for Vaccine Research, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Wenjie Wang
- Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - Shane Miersch
- The Donnelly Centre, University of Toronto, Toronto, ON, Canada
| | - Anthony Orvedahl
- Department of Pediatrics, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - Aidan R Cole
- Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - Monica F Sentmanat
- Genome Engineering and iPSC Center (GEiC), Department of Genetics, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - Nawneet Mishra
- Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - Devin A Boyles
- Center for Vaccine Research, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Zachary T Koenig
- Center for Vaccine Research, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Infectious Diseases and Microbiology, School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - Michael R Kujawa
- Center for Vaccine Research, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Infectious Diseases and Microbiology, School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
| | - Matthew A Demers
- Center for Vaccine Research, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Ryan M Hoehl
- Center for Vaccine Research, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Austin B Moyle
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO, USA
| | - Nicole D Wagner
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO, USA
| | - Sarah H Stubbs
- Department of Microbiology, Harvard Medical School, Boston, MA, USA
| | - Lia Cardarelli
- The Donnelly Centre, University of Toronto, Toronto, ON, Canada
| | - Joan Teyra
- The Donnelly Centre, University of Toronto, Toronto, ON, Canada
| | - Anita McElroy
- Center for Vaccine Research, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Pediatrics, Division of Pediatric Infectious Disease, University of Pittsburgh, Pittsburgh, PA, USA
| | - Michael L Gross
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO, USA
| | - Sean P J Whelan
- Department of Molecular Microbiology, Washington University in St. Louis, St. Louis, MO, USA
| | - John Doench
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Xiaoxia Cui
- Genome Engineering and iPSC Center (GEiC), Department of Genetics, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - Tom J Brett
- Department of Medicine, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - Sachdev S Sidhu
- The Donnelly Centre, University of Toronto, Toronto, ON, Canada
| | - Herbert W Virgin
- Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA; Current address: Vir Biotechnology, San Francisco, CA, USA
| | - Takeshi Egawa
- Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - Daisy W Leung
- Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA; Department of Medicine, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - Gaya K Amarasinghe
- Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA.
| | - Amy L Hartman
- Center for Vaccine Research, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Infectious Diseases and Microbiology, School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA.
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14
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Terasaki K, Kalveram B, Johnson KN, Juelich T, Smith JK, Zhang L, Freiberg AN, Makino S. Rift Valley fever virus 78kDa envelope protein attenuates virus replication in macrophage-derived cell lines and viral virulence in mice. PLoS Negl Trop Dis 2021; 15:e0009785. [PMID: 34516560 PMCID: PMC8460012 DOI: 10.1371/journal.pntd.0009785] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 09/23/2021] [Accepted: 09/02/2021] [Indexed: 12/27/2022] Open
Abstract
Rift Valley fever virus (RVFV) is a mosquito-borne bunyavirus with a wide host range including ruminants and humans. RVFV outbreaks have had devastating effects on public health and the livestock industry in African countries. However, there is no approved RVFV vaccine for human use in non-endemic countries and no FDA-approved antiviral drug for RVFV treatment. The RVFV 78kDa protein (P78), which is a membrane glycoprotein, plays a role in virus dissemination in the mosquito host, but its biological role in mammalian hosts remains unknown. We generated an attenuated RVFV MP-12 strain-derived P78-High virus and a virulent ZH501 strain-derived ZH501-P78-High virus, both of which expressed a higher level of P78 and carried higher levels of P78 in the virion compared to their parental viruses. We also generated another MP-12-derived mutant virus (P78-KO virus) that does not express P78. MP-12 and P78-KO virus replicated to similar levels in fibroblast cell lines and Huh7 cells, while P78-High virus replicated better than MP-12 in Vero E6 cells, fibroblast cell lines, and Huh7 cells. Notably, P78-High virus and P78-KO virus replicated less efficiently and more efficiently, respectively, than MP-12 in macrophage cell lines. ZH501-P78-High virus also replicated poorly in macrophage cell lines. Our data further suggest that inefficient binding of P78-High virus to the cells led to inefficient virus internalization, low virus infectivity and reduced virus replication in a macrophage cell line. P78-High virus and P78-KO virus showed lower and higher virulence than MP-12, respectively, in young mice. ZH501-P78-High virus also exhibited lower virulence than ZH501 in mice. These data suggest that high levels of P78 expression attenuate RVFV virulence by preventing efficient virus replication in macrophages. Genetic alteration leading to increased P78 expression may serve as a novel strategy for the attenuation of RVFV virulence and generation of safe RVFV vaccines.
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Affiliation(s)
- Kaori Terasaki
- Department of Microbiology and Immunology, The University of Texas Medical Branch, Galveston, Texas, United States of America
- Institute of Human Infection and Immunity, The University of Texas Medical Branch, Galveston, Texas, United States of America
- * E-mail: (KT); (SM)
| | - Birte Kalveram
- Department of Pathology, The University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Kendra N. Johnson
- Department of Microbiology and Immunology, The University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Terry Juelich
- Department of Pathology, The University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Jennifer K. Smith
- Department of Pathology, The University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Lihong Zhang
- Department of Pathology, The University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Alexander N. Freiberg
- Institute of Human Infection and Immunity, The University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Pathology, The University of Texas Medical Branch, Galveston, Texas, United States of America
- Center for Biodefense and Emerging Infectious Diseases, the University of Texas Medical Branch, Galveston, Texas, United States of America
- Center for Tropical Diseases, The University of Texas Medical Branch, Galveston, Texas, United States of America
- Sealy Institute for Vaccine Sciences, The University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Shinji Makino
- Department of Microbiology and Immunology, The University of Texas Medical Branch, Galveston, Texas, United States of America
- Institute of Human Infection and Immunity, The University of Texas Medical Branch, Galveston, Texas, United States of America
- Center for Biodefense and Emerging Infectious Diseases, the University of Texas Medical Branch, Galveston, Texas, United States of America
- Center for Tropical Diseases, The University of Texas Medical Branch, Galveston, Texas, United States of America
- Sealy Institute for Vaccine Sciences, The University of Texas Medical Branch, Galveston, Texas, United States of America
- * E-mail: (KT); (SM)
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15
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The Input of Structural Vaccinology in the Search for Vaccines against Bunyaviruses. Viruses 2021; 13:v13091766. [PMID: 34578349 PMCID: PMC8473429 DOI: 10.3390/v13091766] [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: 07/12/2021] [Revised: 08/22/2021] [Accepted: 08/28/2021] [Indexed: 11/26/2022] Open
Abstract
A significant increase in the number of viruses causing unexpected illnesses and epidemics among humans, wildlife and livestock has been observed in recent years. These new or re-emerging viruses have often caught the scientific community off-guard, without sufficient knowledge to combat them, as shown by the current coronavirus pandemic. The bunyaviruses, together with the flaviviruses and filoviruses, are the major etiological agents of viral hemorrhagic fever, and several of them have been listed as priority pathogens by the World Health Organization for which insufficient countermeasures exist. Based on new techniques allowing rapid analysis of the repertoire of protective antibodies induced during infection, combined with atomic-level structural information on viral surface proteins, structural vaccinology is now instrumental in the combat against newly emerging threats, as it allows rapid rational design of novel vaccine antigens. Here, we discuss the contribution of structural vaccinology and the current challenges that remain in the search for an efficient vaccine against some of the deadliest bunyaviruses.
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16
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Meier K, Thorkelsson SR, Quemin ERJ, Rosenthal M. Hantavirus Replication Cycle-An Updated Structural Virology Perspective. Viruses 2021; 13:1561. [PMID: 34452426 PMCID: PMC8402763 DOI: 10.3390/v13081561] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/31/2021] [Accepted: 08/02/2021] [Indexed: 11/17/2022] Open
Abstract
Hantaviruses infect a wide range of hosts including insectivores and rodents and can also cause zoonotic infections in humans, which can lead to severe disease with possible fatal outcomes. Hantavirus outbreaks are usually linked to the population dynamics of the host animals and their habitats being in close proximity to humans, which is becoming increasingly important in a globalized world. Currently there is neither an approved vaccine nor a specific and effective antiviral treatment available for use in humans. Hantaviruses belong to the order Bunyavirales with a tri-segmented negative-sense RNA genome. They encode only five viral proteins and replicate and transcribe their genome in the cytoplasm of infected cells. However, many details of the viral amplification cycle are still unknown. In recent years, structural biology methods such as cryo-electron tomography, cryo-electron microscopy, and crystallography have contributed essentially to our understanding of virus entry by membrane fusion as well as genome encapsidation by the nucleoprotein. In this review, we provide an update on the hantavirus replication cycle with a special focus on structural virology aspects.
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Affiliation(s)
- Kristina Meier
- Department of Virology, Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany;
| | - Sigurdur R. Thorkelsson
- Centre for Structural Systems Biology, Leibniz Institute for Experimental Virology, University of Hamburg, 22607 Hamburg, Germany;
| | - Emmanuelle R. J. Quemin
- Centre for Structural Systems Biology, Leibniz Institute for Experimental Virology, University of Hamburg, 22607 Hamburg, Germany;
| | - Maria Rosenthal
- Department of Virology, Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany;
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, 22525 Hamburg, Germany
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17
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Sandfly Fever Sicilian Virus-Leishmania major co-infection modulates innate inflammatory response favoring myeloid cell infections and skin hyperinflammation. PLoS Negl Trop Dis 2021; 15:e0009638. [PMID: 34310619 PMCID: PMC8341699 DOI: 10.1371/journal.pntd.0009638] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 08/05/2021] [Accepted: 07/09/2021] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The leishmaniases are a group of sandfly-transmitted diseases caused by species of the protozoan parasite, Leishmania. With an annual incidence of 1 million cases, 1 billion people living in Leishmania-endemic regions, and nearly 30,000 deaths each year, leishmaniasis is a major global public health concern. While phlebotomine sandflies are well-known as vectors of Leishmania, they are also the vectors of various phleboviruses, including Sandfly Fever Sicilian Virus (SFSV). Cutaneous leishmaniasis (CL), caused by Leishmania major (L. major), among other species, results in development of skin lesions on the infected host. Importantly, there exists much variation in the clinical manifestation between individuals. We propose that phleboviruses, vectored by and found in the same sandfly guts as Leishmania, may be a factor in determining CL severity. It was reported by our group that Leishmania exosomes are released into the gut of the sandfly vector and co-inoculated during blood meals, where they exacerbate CL skin lesions. We hypothesized that, when taking a blood meal, the sandfly vector infects the host with Leishmania parasites and exosomes as well as phleboviruses, and that this viral co-infection results in a modulation of leishmaniasis. METHODOLOGY/PRINCIPAL FINDINGS In vitro, we observed modulation by SFSV in MAP kinase signaling as well as in the IRF3 pathway that resulted in a pro-inflammatory phenotype. Additionally, we found that SFSV and L. major co-infection resulted in an exacerbation of leishmaniasis in vivo, and by using endosomal (Toll-like receptor) TLR3, and MAVS knock-out mice, deduced that SFSV's hyperinflammatory effect was TLR3- and MAVS-dependent. Critically, we observed that L. major and SFSV co-infected C57BL/6 mice demonstrated significantly higher parasite burden than mice solely infected with L. major. Furthermore, viral presence increased leukocyte influx in vivo. This influx was accompanied by elevated total extracellular vesicle numbers. Interestingly, L. major displayed higher infectiveness with coincident phleboviral infection compared to L. major infection alone. CONCLUSION/SIGNIFICANCE Overall our work represents novel findings that contribute towards understanding the causal mechanisms governing cutaneous leishmaniasis pathology. Better comprehension of the potential role of viral co-infection could lead to treatment regimens with enhanced effectiveness.
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18
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Rath CT, de Carvalho Vivarini A, Pereira RM, Lopes UG. Production, Quantitation, and Infection of Amazonian Icoaraci Phlebovirus (Bunyaviridae). Bio Protoc 2021; 11:e4072. [PMID: 34327269 PMCID: PMC8292122 DOI: 10.21769/bioprotoc.4072] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 04/01/2021] [Accepted: 04/08/2021] [Indexed: 11/02/2022] Open
Abstract
Phlebotomine vectors, sand flies of the order Diptera, are known to transmit Leishmania parasites as well as RNA viruses (arboviruses) to humans. The arbovirus, Icoaraci Phlebovirus (BeAN 24262 - ICOV), used in this study was isolated from Nectomys rodents, a mammalian species that is the same natural sylvatic reservoir of Leishmania (Leishmania) amazonensis. This Leishmania species is distributed in primary and secondary forests in Brazil and other countries in America and causes localized and diffuse anergic skin lesions. In our recent studies, we observed an aggravation of the protozoan infection by ICOV through the modulation of cytokine expression, such as IL-10 and IFN-β, enhancing the parasite load and possibly the pathogenesis. Efficient viral production and quantitation had to be developed and standardized to ensure that immuno-molecular assays provide consistent and reproducible viral infection results. The standardization of these procedures becomes a particularly useful tool in research, with several applications in understanding the interaction between the host cell and Phlebovirus, as well as co-infections, allowing the study of intracellular signaling pathways. Here, we detail a protocol that allows the production and quantitation of the Icoaraci Phlebovirus using BHK-21 cells (baby hamster kidney cells) and subsequent infection of peritoneal macrophages from C57BL/6 mice.
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Affiliation(s)
- Carolina Torturella Rath
- Department of Medicine, Division of Infectious Diseases, University of British Columbia, Vancouver, British Columbia, Canada
| | - Aislan de Carvalho Vivarini
- Laboratory of Molecular Parasitology, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Renata M. Pereira
- Institute of Microbiology Paulo de Góes, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Ulisses Gazos Lopes
- Laboratory of Molecular Parasitology, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
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19
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Léger P, Lozach PY. [Rift Valley fever virus and the amazing NSs protein]. Med Sci (Paris) 2021; 37:601-608. [PMID: 34180819 DOI: 10.1051/medsci/2021090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Rift Valley Fever Virus (RVFV) is an emerging zoonotic pathogen transmitted to humans and livestock through mosquito bites, which was first isolated in Kenya in 1930. The virus is classified by the WHO among the pathogens for which there is an urgent need to develop research, diagnostics, and therapies. However, the efforts developed to control the virus remain limited, and the virus is not well characterized. In this article, we will introduce RVFV and then focus on its virulence factor, the nonstructural protein NSs. We will mainly discuss the ability of this viral protein to form amyloid-like fibrils and its implication in the neurotoxicity associated with RVFV infection.
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Affiliation(s)
- Psylvia Léger
- CellNetworks, CIID (Cluster of Excellence and Center for Integrative Infectious Disease Research), Virology, University hospital Heidelberg, Im Neuenheimer Feld 344, 69120 Heidelberg, Allemagne
| | - Pierre-Yves Lozach
- CellNetworks, CIID (Cluster of Excellence and Center for Integrative Infectious Disease Research), Virology, University hospital Heidelberg, Im Neuenheimer Feld 344, 69120 Heidelberg, Allemagne - Univ. Lyon, INRAe, EPHE, IVPC (Infections virales et pathologie comparée), 50 avenue Tony Garnier, 69007 Lyon, France
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20
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Chapman NS, Zhao H, Kose N, Westover JB, Kalveram B, Bombardi R, Rodriguez J, Sutton R, Genualdi J, LaBeaud AD, Mutuku FM, Pittman PR, Freiberg AN, Gowen BB, Fremont DH, Crowe JE. Potent neutralization of Rift Valley fever virus by human monoclonal antibodies through fusion inhibition. Proc Natl Acad Sci U S A 2021; 118:e2025642118. [PMID: 33782133 PMCID: PMC8040655 DOI: 10.1073/pnas.2025642118] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Rift Valley fever virus (RVFV), an emerging arboviral and zoonotic bunyavirus, causes severe disease in livestock and humans. Here, we report the isolation of a panel of monoclonal antibodies (mAbs) from the B cells of immune individuals following natural infection in Kenya or immunization with MP-12 vaccine. The B cell responses of individuals who were vaccinated or naturally infected recognized similar epitopes on both Gc and Gn proteins. The Gn-specific mAbs and two mAbs that do not recognize either monomeric Gc or Gn alone but recognized the hetero-oligomer glycoprotein complex (Gc+Gn) when Gc and Gn were coexpressed exhibited potent neutralizing activities in vitro, while Gc-specific mAbs exhibited relatively lower neutralizing capacity. The two Gc+Gn-specific mAbs and the Gn domain A-specific mAbs inhibited RVFV fusion to cells, suggesting that mAbs can inhibit the exposure of the fusion loop in Gc, a class II fusion protein, and thus prevent fusion by an indirect mechanism without direct fusion loop contact. Competition-binding analysis with coexpressed Gc/Gn and mutagenesis library screening indicated that these mAbs recognize four major antigenic sites, with two sites of vulnerability for neutralization on Gn. In experimental models of infection in mice, representative mAbs recognizing three of the antigenic sites reduced morbidity and mortality when used at a low dose in both prophylactic and therapeutic settings. This study identifies multiple candidate mAbs that may be suitable for use in humans against RVFV infection and highlights fusion inhibition against bunyaviruses as a potential contributor to potent antibody-mediated neutralization.
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Affiliation(s)
- Nathaniel S Chapman
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232
| | - Haiyan Zhao
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110
| | - Nurgun Kose
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232
| | - Jonna B Westover
- Department of Animal, Dairy, and Veterinary Sciences, Utah State University, Logan, UT 84322
| | - Birte Kalveram
- Department of Pathology, The University of Texas Medical Branch at Galveston, Galveston, TX 77555
| | - Robin Bombardi
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232
| | - Jessica Rodriguez
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232
| | - Rachel Sutton
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232
| | - Joseph Genualdi
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232
| | - A Desiree LaBeaud
- Department of Pediatrics, Division of Infectious Diseases, Stanford University School of Medicine, Stanford, CA 94305
| | - Francis M Mutuku
- Department of Environment and Health Sciences, Technical University of Mombasa, Mombasa, Kenya
| | - Phillip R Pittman
- Medical Research and Material Command, U.S. Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD 21702
| | - Alexander N Freiberg
- Department of Pathology, The University of Texas Medical Branch at Galveston, Galveston, TX 77555
- Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch at Galveston, Galveston, TX 77555
- Sealy Institute for Vaccine Sciences, University of Texas Medical Branch at Galveston, Galveston, TX 77555
| | - Brian B Gowen
- Department of Animal, Dairy, and Veterinary Sciences, Utah State University, Logan, UT 84322
| | - Daved H Fremont
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110
| | - James E Crowe
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232;
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232
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21
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Bermúdez-Méndez E, Katrukha EA, Spruit CM, Kortekaas J, Wichgers Schreur PJ. Visualizing the ribonucleoprotein content of single bunyavirus virions reveals more efficient genome packaging in the arthropod host. Commun Biol 2021; 4:345. [PMID: 33753850 PMCID: PMC7985392 DOI: 10.1038/s42003-021-01821-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 02/09/2021] [Indexed: 01/31/2023] Open
Abstract
Bunyaviruses have a genome that is divided over multiple segments. Genome segmentation complicates the generation of progeny virus, since each newly formed virus particle should preferably contain a full set of genome segments in order to disseminate efficiently within and between hosts. Here, we combine immunofluorescence and fluorescence in situ hybridization techniques to simultaneously visualize bunyavirus progeny virions and their genomic content at single-molecule resolution in the context of singly infected cells. Using Rift Valley fever virus and Schmallenberg virus as prototype tri-segmented bunyaviruses, we show that bunyavirus genome packaging is influenced by the intracellular viral genome content of individual cells, which results in greatly variable packaging efficiencies within a cell population. We further show that bunyavirus genome packaging is more efficient in insect cells compared to mammalian cells and provide new insights on the possibility that incomplete particles may contribute to bunyavirus spread as well.
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Affiliation(s)
- Erick Bermúdez-Méndez
- Department of Virology, Wageningen Bioveterinary Research, Lelystad, The Netherlands
- Laboratory of Virology, Wageningen University, Wageningen, The Netherlands
| | - Eugene A Katrukha
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Cindy M Spruit
- Department of Virology, Wageningen Bioveterinary Research, Lelystad, The Netherlands
- Department of Chemical Biology & Drug Discovery, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
| | - Jeroen Kortekaas
- Department of Virology, Wageningen Bioveterinary Research, Lelystad, The Netherlands
- Laboratory of Virology, Wageningen University, Wageningen, The Netherlands
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22
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Hulswit RJG, Paesen GC, Bowden TA, Shi X. Recent Advances in Bunyavirus Glycoprotein Research: Precursor Processing, Receptor Binding and Structure. Viruses 2021; 13:353. [PMID: 33672327 PMCID: PMC7926653 DOI: 10.3390/v13020353] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 02/13/2021] [Accepted: 02/15/2021] [Indexed: 01/04/2023] Open
Abstract
The Bunyavirales order accommodates related viruses (bunyaviruses) with segmented, linear, single-stranded, negative- or ambi-sense RNA genomes. Their glycoproteins form capsomeric projections or spikes on the virion surface and play a crucial role in virus entry, assembly, morphogenesis. Bunyavirus glycoproteins are encoded by a single RNA segment as a polyprotein precursor that is co- and post-translationally cleaved by host cell enzymes to yield two mature glycoproteins, Gn and Gc (or GP1 and GP2 in arenaviruses). These glycoproteins undergo extensive N-linked glycosylation and despite their cleavage, remain associated to the virion to form an integral transmembrane glycoprotein complex. This review summarizes recent advances in our understanding of the molecular biology of bunyavirus glycoproteins, including their processing, structure, and known interactions with host factors that facilitate cell entry.
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Affiliation(s)
- Ruben J. G. Hulswit
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK; (R.J.G.H.); (G.C.P.)
| | - Guido C. Paesen
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK; (R.J.G.H.); (G.C.P.)
| | - Thomas A. Bowden
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK; (R.J.G.H.); (G.C.P.)
| | - Xiaohong Shi
- MRC-University of Glasgow Centre for Virus Research, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow G61 1QH, UK
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23
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Entry of Phenuiviruses into Mammalian Host Cells. Viruses 2021; 13:v13020299. [PMID: 33672975 PMCID: PMC7918600 DOI: 10.3390/v13020299] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Revised: 02/08/2021] [Accepted: 02/11/2021] [Indexed: 12/22/2022] Open
Abstract
Phenuiviridae is a large family of arthropod-borne viruses with over 100 species worldwide. Several cause severe diseases in both humans and livestock. Global warming and the apparent geographical expansion of arthropod vectors are good reasons to seriously consider these viruses potential agents of emerging diseases. With an increasing frequency and number of epidemics, some phenuiviruses represent a global threat to public and veterinary health. This review focuses on the early stage of phenuivirus infection in mammalian host cells. We address current knowledge on each step of the cell entry process, from virus binding to penetration into the cytosol. Virus receptors, endocytosis, and fusion mechanisms are discussed in light of the most recent progress on the entry of banda-, phlebo-, and uukuviruses, which together constitute the three prominent genera in the Phenuiviridae family.
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24
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Wright D, Allen ER, Clark MH, Gitonga JN, Karanja HK, Hulswit RJ, Taylor I, Biswas S, Marshall J, Mwololo D, Muriuki J, Bett B, Bowden TA, Warimwe GM. Naturally Acquired Rift Valley Fever Virus Neutralizing Antibodies Predominantly Target the Gn Glycoprotein. iScience 2020; 23:101669. [PMID: 33134899 PMCID: PMC7588868 DOI: 10.1016/j.isci.2020.101669] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 09/28/2020] [Accepted: 10/08/2020] [Indexed: 11/30/2022] Open
Abstract
Rift Valley fever (RVF) is a viral hemorrhagic disease first discovered in Kenya in 1930. Numerous animal studies have demonstrated that protective immunity is acquired following RVF virus (RVFV) infection and that this correlates with acquisition of virus-neutralizing antibodies (nAbs) that target the viral envelope glycoproteins. However, naturally acquired immunity to RVF in humans is poorly described. Here, we characterized the immune response to the viral envelope glycoproteins, Gn and Gc, in RVFV-exposed Kenyan adults. Long-lived IgG (dominated by IgG1 subclass) and T cell responses were detected against both Gn and Gc. However, antigen-specific antibody depletion experiments showed that Gn-specific antibodies dominate the RVFV nAb response. IgG avidity against Gn, but not Gc, correlated with nAb titers. These data are consistent with the greater level of immune accessibility of Gn on the viral envelope surface and confirm the importance of Gn as an integral component for RVF vaccine development.
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Affiliation(s)
- Daniel Wright
- KEMRI-Wellcome Trust Research Programme, CGMRC, PO Box 230-80108, Kilifi, Kenya
- The Jenner Institute, University of Oxford, Oxford OX3 7DQ, UK
| | - Elizabeth R. Allen
- Wellcome Centre for Human Genetics, Division of Structural Biology, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | | | - John N. Gitonga
- KEMRI-Wellcome Trust Research Programme, CGMRC, PO Box 230-80108, Kilifi, Kenya
| | - Henry K. Karanja
- KEMRI-Wellcome Trust Research Programme, CGMRC, PO Box 230-80108, Kilifi, Kenya
| | - Ruben J.G. Hulswit
- Wellcome Centre for Human Genetics, Division of Structural Biology, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Iona Taylor
- The Jenner Institute, University of Oxford, Oxford OX3 7DQ, UK
| | - Sumi Biswas
- The Jenner Institute, University of Oxford, Oxford OX3 7DQ, UK
| | | | - Damaris Mwololo
- International Livestock Research Institute, PO Box 30709, Nairobi 00100, Kenya
| | - John Muriuki
- International Livestock Research Institute, PO Box 30709, Nairobi 00100, Kenya
| | - Bernard Bett
- International Livestock Research Institute, PO Box 30709, Nairobi 00100, Kenya
| | - Thomas A. Bowden
- Wellcome Centre for Human Genetics, Division of Structural Biology, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - George M. Warimwe
- KEMRI-Wellcome Trust Research Programme, CGMRC, PO Box 230-80108, Kilifi, Kenya
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford OX3 7FZ, UK
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25
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Characterization of Two Neutralizing Antibodies against Rift Valley Fever Virus Gn Protein. Viruses 2020; 12:v12030259. [PMID: 32120864 PMCID: PMC7150882 DOI: 10.3390/v12030259] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 02/23/2020] [Accepted: 02/25/2020] [Indexed: 02/06/2023] Open
Abstract
The Rift Valley fever virus (RVFV) is an arthropod-borne virus that can not only cause severe disease in domestic animals but also in humans. However, the licensed vaccines or available therapeutics for humans do not exist. Here, we report two Gn-specific neutralizing antibodies (NAbs), isolated from a rhesus monkey immunized with recombinant human adenoviruses type 4 expressing Rift Valley fever virus Gn and Gc protein (rHAdV4-GnGcopt). The two NAbs were both able to protect host cells from RVFV infection. The interactions between NAbs and Gn were then characterized to demonstrate that these two NAbs might preclude RVFV glycoprotein rearrangement, hindering the exposure of fusion loops in Gc to endosomal membranes after the virus invades the host cell. The target region for the two NAbs is located in the Gn domain III, implying that Gn is a desired target for developing vaccines and neutralizing antibodies against RVFV.
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26
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Allen ER, Krumm SA, Raghwani J, Halldorsson S, Elliott A, Graham VA, Koudriakova E, Harlos K, Wright D, Warimwe GM, Brennan B, Huiskonen JT, Dowall SD, Elliott RM, Pybus OG, Burton DR, Hewson R, Doores KJ, Bowden TA. A Protective Monoclonal Antibody Targets a Site of Vulnerability on the Surface of Rift Valley Fever Virus. Cell Rep 2019; 25:3750-3758.e4. [PMID: 30590046 PMCID: PMC6315105 DOI: 10.1016/j.celrep.2018.12.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 10/30/2018] [Accepted: 11/29/2018] [Indexed: 12/31/2022] Open
Abstract
The Gn subcomponent of the Gn-Gc assembly that envelopes the human and animal pathogen, Rift Valley fever virus (RVFV), is a primary target of the neutralizing antibody response. To better understand the molecular basis for immune recognition, we raised a class of neutralizing monoclonal antibodies (nAbs) against RVFV Gn, which exhibited protective efficacy in a mouse infection model. Structural characterization revealed that these nAbs were directed to the membrane-distal domain of RVFV Gn and likely prevented virus entry into a host cell by blocking fusogenic rearrangements of the Gn-Gc lattice. Genome sequence analysis confirmed that this region of the RVFV Gn-Gc assembly was under selective pressure and constituted a site of vulnerability on the virion surface. These data provide a blueprint for the rational design of immunotherapeutics and vaccines capable of preventing RVFV infection and a model for understanding Ab-mediated neutralization of bunyaviruses more generally.
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Affiliation(s)
- Elizabeth R Allen
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Stefanie A Krumm
- Kings College London, Department of Infectious Diseases, 2nd Floor, Borough Wing, Guy's Hospital, Great Maze Pond, London SE1 9RT, UK
| | - Jayna Raghwani
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, Old Road, Oxford OX3 7LF, UK
| | - Steinar Halldorsson
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Angela Elliott
- MRC-University of Glasgow Centre for Virus Research, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, 464 Bearsden Road, Glasgow G61 1QH, UK
| | - Victoria A Graham
- National Infection Service, Virology & Pathogenesis, Public Health England, Porton Down, Salisbury, SP4 0JG Wiltshire, UK
| | - Elina Koudriakova
- MRC-University of Glasgow Centre for Virus Research, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, 464 Bearsden Road, Glasgow G61 1QH, UK
| | - Karl Harlos
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Daniel Wright
- The Jenner Institute, University of Oxford, Oxford OX3 7DQ, UK
| | - George M Warimwe
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford OX3 7FZ, UK; Kenya Medical Research Institute (KEMRI)-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Benjamin Brennan
- MRC-University of Glasgow Centre for Virus Research, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, 464 Bearsden Road, Glasgow G61 1QH, UK
| | - Juha T Huiskonen
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Stuart D Dowall
- National Infection Service, Virology & Pathogenesis, Public Health England, Porton Down, Salisbury, SP4 0JG Wiltshire, UK
| | - Richard M Elliott
- MRC-University of Glasgow Centre for Virus Research, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, 464 Bearsden Road, Glasgow G61 1QH, UK
| | - Oliver G Pybus
- Department of Zoology, University of Oxford, South Parks Road, Oxford, UK
| | - Dennis R Burton
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA; Ragon Institute of MGH, Harvard, and MIT, Cambridge, MA 02139, USA
| | - Roger Hewson
- National Infection Service, Virology & Pathogenesis, Public Health England, Porton Down, Salisbury, SP4 0JG Wiltshire, UK
| | - Katie J Doores
- Kings College London, Department of Infectious Diseases, 2nd Floor, Borough Wing, Guy's Hospital, Great Maze Pond, London SE1 9RT, UK.
| | - Thomas A Bowden
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK; Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA.
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27
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Li S, Zhu X, Guan Z, Huang W, Zhang Y, Kortekaas J, Lozach PY, Peng K. NSs Filament Formation Is Important but Not Sufficient for RVFV Virulence In Vivo. Viruses 2019; 11:v11090834. [PMID: 31500343 PMCID: PMC6783917 DOI: 10.3390/v11090834] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 08/28/2019] [Accepted: 09/03/2019] [Indexed: 02/06/2023] Open
Abstract
Rift Valley fever virus (RVFV) is a mosquito-borne phlebovirus that represents as a serious health threat to both domestic animals and humans. The viral protein NSs is the key virulence factor of RVFV, and has been proposed that NSs nuclear filament formation is critical for its virulence. However, the detailed mechanisms are currently unclear. Here, we generated a T7 RNA polymerase-driven RVFV reverse genetics system based on a strain imported into China (BJ01). Several NSs mutations (T1, T3 and T4) were introduced into the system for investigating the correlation between NSs filament formation and virulence in vivo. The NSs T1 mutant showed distinct NSs filament in the nuclei of infected cells, the T3 mutant diffusively localized in the cytoplasm and the T4 mutant showed fragmented nuclear filament formation. Infection of BALB/c mice with these NSs mutant viruses revealed that the in vivo virulence was severely compromised for all three NSs mutants, including the T1 mutant. This suggests that NSs filament formation is not directly correlated with RVFV virulence in vivo. Results from this study not only shed new light on the virulence mechanism of RVFV NSs but also provided tools for future in-depth investigations of RVFV pathogenesis and anti-RVFV drug screening.
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Affiliation(s)
- Shufen Li
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
- Wuhan National Biosafety Laboratory, Mega-Science Center for Bio-Safety Research, CAS, Wuhan 430071, China.
| | - Xiangtao Zhu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
- University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Zhenqiong Guan
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
- University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Wenfeng Huang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
- University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Yulan Zhang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
- Wuhan National Biosafety Laboratory, Mega-Science Center for Bio-Safety Research, CAS, Wuhan 430071, China.
| | - Jeroen Kortekaas
- Department of Virology, Wageningen Bioveterinary Research, 8211 Lelystad, The Netherlands.
- Laboratory of Virology, Wageningen University, 6701 Wageningen, The Netherlands.
| | - Pierre-Yves Lozach
- Cell Networks-Cluster of Excellence and Center for Integrative Infectious Disease Research, University Hospital Heidelberg, 69115 Heidelberg, Germany.
- IVPC UMR754, INRA, Univ. Lyon, EPHE, 50 Av. Tony Garnier, 69007 Lyon, France.
| | - Ke Peng
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China.
- Wuhan National Biosafety Laboratory, Mega-Science Center for Bio-Safety Research, CAS, Wuhan 430071, China.
- University of Chinese Academy of Sciences, Beijing 100049, China.
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28
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Chen Y, Dessau M, Rotenberg D, Rasmussen DA, Whitfield AE. Entry of bunyaviruses into plants and vectors. Adv Virus Res 2019; 104:65-96. [PMID: 31439153 DOI: 10.1016/bs.aivir.2019.07.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The majority of plant-infecting viruses are transmitted by arthropod vectors that deliver them directly into a living plant cell. There are diverse mechanisms of transmission ranging from direct binding to the insect stylet (non-persistent transmission) to persistent-propagative transmission in which the virus replicates in the insect vector. Despite this diversity in interactions, most arthropods that serve as efficient vectors have feeding strategies that enable them to deliver the virus into the plant cell without extensive damage to the plant and thus effectively inoculate the plant. As such, the primary virus entry mechanism for plant viruses is mediated by the biological vector. Remarkably, viruses that are transmitted in a propagative manner (bunyaviruses, rhabdoviruses, and reoviruses) have developed an ability to replicate in hosts from two kingdoms. Viruses in the order Bunyavirales are of emerging importance and with the advent of new sequencing technologies, we are getting unprecedented glimpses into the diversity of these viruses. Plant-infecting bunyaviruses are transmitted in a persistent, propagative manner must enter two unique types of host cells, plant and insect. In the insect phase of the virus life cycle, the propagative viruses likely use typical cellular entry strategies to traverse cell membranes. In this review, we highlight the transmission and entry strategies of three genera of plant-infecting bunyaviruses: orthotospoviruses, tenuiviruses, and emaraviruses.
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Affiliation(s)
- Yuting Chen
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, United States
| | - Moshe Dessau
- Azrieli Faculty of Medicine, Bar Ilan University, Safed, Israel
| | - Dorith Rotenberg
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, United States
| | - David A Rasmussen
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, United States
| | - Anna E Whitfield
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, United States.
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29
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Abstract
Rift Valley fever (RVF) is a mosquito-borne viral zoonosis that was first discovered in Kenya in 1930 and is now endemic throughout multiple African countries and the Arabian Peninsula. RVF virus primarily infects domestic livestock (sheep, goats, cattle) causing high rates of neonatal mortality and abortion, with human infection resulting in a wide variety of clinical outcomes, ranging from self-limiting febrile illness to life-threatening haemorrhagic diatheses, and miscarriage in pregnant women. Since its discovery, RVF has caused many outbreaks in Africa and the Arabian Peninsula with major impacts on human and animal health. However, options for the control of RVF outbreaks are limited by the lack of licensed human vaccines or therapeutics. For this reason, RVF is prioritized by the World Health Organization for urgent research and development of countermeasures for the prevention and control of future outbreaks. In this review, we highlight the current understanding of RVF, including its epidemiology, pathogenesis, clinical manifestations and status of vaccine development.
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Affiliation(s)
- Daniel Wright
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
- The Jenner Institute, University of Oxford, Oxford OX1 2JD, UK
| | - Jeroen Kortekaas
- Wageningen Bioveterinary Research, Lelystad, The Netherlands
- Laboratory of Virology, Wageningen University, Wageningen, The Netherlands
| | - Thomas A. Bowden
- Wellcome Centre for Human Genetics, Division of Structural Biology, University of Oxford, Oxford OX1 2JD, UK
| | - George M. Warimwe
- KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford OX1 2JD, UK
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30
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Ma J, Chen R, Huang W, Nie J, Liu Q, Wang Y, Yang X. In vitro and in vivo efficacy of a Rift Valley fever virus vaccine based on pseudovirus. Hum Vaccin Immunother 2019; 15:2286-2294. [PMID: 31170027 DOI: 10.1080/21645515.2019.1627820] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Rift Valley fever virus (RVFV), a recognized category A priority pathogen, causes large outbreaks of Rift Valley fever with some fatalities in humans in humans and huge economic losses in livestock. As wild-type RVFV must be handled in BSL-3 or BSL-4 laboratories, we constructed a high-titer vesicular stomatitis virus (VSV) pseudotype bearing RVFV envelope glycoproteins to detect neutralizing antibodies in vitro under BSL-2 conditions. The neutralizing properties of 39 amino acid mutant sites that have occurred naturally over time in the RVFV envelope glycoproteins were analyzed with their corresponding pseudoviral mutants separately. Compared with the results in the primary strain, the variants showed no statistically significant differences. We next established a Balb/c mouse pseudovirus infection model for detecting neutralizing antibodies against pseudovirus. Five immunizations with pseudoviral DNA protected the mice from infection with the pseudovirus. Bioluminescence imaging, which we used to evaluate viral dissemination and distribution in the mice, showed a good relationship between the neutralizing antibodies titers in vitro. These pseudovirus methods will allow for the safe determination of neutralizing antibodies in vivo and in vitro, and will assist with studies on vaccines and drugs against RVFV with the long term objective of Rift Valley fever prevention.
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Affiliation(s)
- Jian Ma
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, National Institutes for Food and Drug Control (NIFDC) , Beijing , China.,National Engineering Technology Research Center of Combination Vaccines , Wuhan , China
| | - Ruifeng Chen
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, National Institutes for Food and Drug Control (NIFDC) , Beijing , China
| | - Weijin Huang
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, National Institutes for Food and Drug Control (NIFDC) , Beijing , China
| | - Jianhui Nie
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, National Institutes for Food and Drug Control (NIFDC) , Beijing , China
| | - Qiang Liu
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, National Institutes for Food and Drug Control (NIFDC) , Beijing , China
| | - Youchun Wang
- Division of HIV/AIDS and Sex-transmitted Virus Vaccines, National Institutes for Food and Drug Control (NIFDC) , Beijing , China
| | - Xiaoming Yang
- National Engineering Technology Research Center of Combination Vaccines , Wuhan , China.,China National Biotec Group Company Limited , Beijing , China
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31
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Rath CT, Schnellrath LC, Damaso CR, de Arruda LB, Vasconcelos PFDC, Gomes C, Laurenti MD, Calegari Silva TC, Vivarini ÁDC, Fasel N, Pereira RMS, Lopes UG. Amazonian Phlebovirus (Bunyaviridae) potentiates the infection of Leishmania (Leishmania) amazonensis: Role of the PKR/IFN1/IL-10 axis. PLoS Negl Trop Dis 2019; 13:e0007500. [PMID: 31216268 PMCID: PMC6602282 DOI: 10.1371/journal.pntd.0007500] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 07/01/2019] [Accepted: 05/30/2019] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Leishmania parasites are transmitted to vertebrate hosts by phlebotomine sandflies and, in humans, may cause tegumentary or visceral leishmaniasis. The role of PKR (dsRNA activated kinase) and Toll-like receptor 3 (TLR3) activation in the control of Leishmania infection highlights the importance of the engagement of RNA sensors, which are usually involved in the antiviral cell response, in the fate of parasitism by Leishmania. We tested the hypothesis that Phlebovirus, a subgroup of the Bunyaviridae, transmitted by sandflies, would interfere with Leishmania infection. METHODOLOGY/PRINCIPAL FINDINGS We tested two Phlebovirus isolates, Icoaraci and Pacui, from the rodents Nectomys sp. and Oryzomys sp., respectively, both natural sylvatic reservoir of Leishmania (Leishmania) amazonensis from the Amazon region. Phlebovirus coinfection with L. (L.) amazonensis in murine macrophages led to increased intracellular growth of L. (L.) amazonensis. Further studies with Icoaraci coinfection revealed the requirement of the PKR/IFN1 axis on the exacerbation of the parasite infection. L. (L.) amazonensis and Phlebovirus coinfection potentiated PKR activation and synergistically induced the expression of IFNβ and IL-10. Importantly, in vivo coinfection of C57BL/6 mice corroborated the in vitro data. The exacerbation effect of RNA virus on parasite infection may be specific because coinfection with dengue virus (DENV2) exerted the opposite effect on parasite load. CONCLUSIONS Altogether, our data suggest that coinfections with specific RNA viruses shared by vectors or reservoirs of Leishmania may enhance and sustain the activation of host cellular RNA sensors, resulting in aggravation of the parasite infection. The present work highlights new perspectives for the investigation of antiviral pathways as important modulators of protozoan infections.
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Affiliation(s)
- Carolina Torturella Rath
- Laboratory of Molecular Parasitology, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Laila Castro Schnellrath
- Laboratory of Molecular Biology of Virus, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Clarissa R. Damaso
- Laboratory of Molecular Biology of Virus, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Luciana Barros de Arruda
- Laboratório de Genética e Imunologia das Infecções Virais, Departamento de Virologia, Instituto de Microbiologia Prof. Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | | | - Claudia Gomes
- Department of Pathology, Medical School, University of São Paulo, Brazil
| | | | - Teresa Cristina Calegari Silva
- Laboratory of Molecular Parasitology, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Áislan de Carvalho Vivarini
- Laboratory of Molecular Parasitology, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Nicolas Fasel
- Department of Biochemistry, University of Lausanne, Switzerland
| | - Renata Meirelles Santos Pereira
- Institute of Microbiology Paulo de Góes, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
- * E-mail: (RMSP); (UGL)
| | - Ulisses Gazos Lopes
- Laboratory of Molecular Parasitology, Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
- * E-mail: (RMSP); (UGL)
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32
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Mbewana S, Meyers AE, Rybicki EP. Chimaeric Rift Valley Fever Virus-Like Particle Vaccine Candidate Production in Nicotiana benthamiana. Biotechnol J 2019; 14:e1800238. [PMID: 30488669 DOI: 10.1002/biot.201800238] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 11/13/2018] [Indexed: 01/21/2023]
Abstract
Rift Valley fever virus (RVFV) is an emerging mosquito-borne virus and hemorrhagic fever agent, which causes abortion storms in farmed small ruminants and potentially causes miscarriages in humans. Although live-attenuated vaccines are available for animals, they can only be used in endemic areas and there are currently no commercially available vaccines for humans. Here the authors describe the production of chimaeric RVFV virus-like particles transiently expressed in Nicotiana benthamiana by Agrobacterium tumefaciens-mediated gene transfer. The glycoprotein (Gn) gene is modified by removing its ectodomain (Gne) and fusing it to the transmembrane domain and cytosolic tail-encoding region of avian influenza H5N1 hemagglutinin. This is expressed transiently in N. benthamiana with purified protein yields calculated to be ≈57 mg kg-1 fresh weight. Transmission electron microscopy shows putative chimaeric RVFV Gne-HA particles of 49-60 nm which are immunogenic, eliciting Gn-specific antibody responses in vaccinated mice without the use of adjuvant. To our knowledge, this is the first demonstration of the synthesis of Gne-HA chimaeric RVFV VLPs and the first demonstration of a detectable yield of RVFV Gn in plants.
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Affiliation(s)
- Sandiswa Mbewana
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Private Bag X3, 22 University Ave, Rondebosch 7700, Cape Town, South Africa
| | - Ann E Meyers
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Private Bag X3, 22 University Ave, Rondebosch 7700, Cape Town, South Africa
| | - Edward P Rybicki
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Private Bag X3, 22 University Ave, Rondebosch 7700, Cape Town, South Africa
- Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Anzio Road, Observatory 7925, South Africa
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33
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Sperber HS, Welke RW, Petazzi RA, Bergmann R, Schade M, Shai Y, Chiantia S, Herrmann A, Schwarzer R. Self-association and subcellular localization of Puumala hantavirus envelope proteins. Sci Rep 2019; 9:707. [PMID: 30679542 PMCID: PMC6345964 DOI: 10.1038/s41598-018-36879-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 11/28/2018] [Indexed: 01/08/2023] Open
Abstract
Hantavirus assembly and budding are governed by the surface glycoproteins Gn and Gc. In this study, we investigated the glycoproteins of Puumala, the most abundant Hantavirus species in Europe, using fluorescently labeled wild-type constructs and cytoplasmic tail (CT) mutants. We analyzed their intracellular distribution, co-localization and oligomerization, applying comprehensive live, single-cell fluorescence techniques, including confocal microscopy, imaging flow cytometry, anisotropy imaging and Number&Brightness analysis. We demonstrate that Gc is significantly enriched in the Golgi apparatus in absence of other viral components, while Gn is mainly restricted to the endoplasmic reticulum (ER). Importantly, upon co-expression both glycoproteins were found in the Golgi apparatus. Furthermore, we show that an intact CT of Gc is necessary for efficient Golgi localization, while the CT of Gn influences protein stability. Finally, we found that Gn assembles into higher-order homo-oligomers, mainly dimers and tetramers, in the ER while Gc was present as mixture of monomers and dimers within the Golgi apparatus. Our findings suggest that PUUV Gc is the driving factor of the targeting of Gc and Gn to the Golgi region, while Gn possesses a significantly stronger self-association potential.
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Affiliation(s)
- Hannah Sabeth Sperber
- Institute for Biology, IRI Life Science, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115, Berlin, Germany.,Vitalant Research Institute, 270 Masonic Ave, San Francisco, CA, 94118, USA
| | - Robert-William Welke
- Institute for Biology, IRI Life Science, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115, Berlin, Germany
| | - Roberto Arturo Petazzi
- University of Potsdam, Institute of Biochemistry and Biology, Karl-Liebknecht-Str. 24-25, 14476, Potsdam, Germany
| | - Ronny Bergmann
- Institute for Biology, IRI Life Science, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115, Berlin, Germany
| | - Matthias Schade
- Institute for Biology, IRI Life Science, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115, Berlin, Germany
| | - Yechiel Shai
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Salvatore Chiantia
- University of Potsdam, Institute of Biochemistry and Biology, Karl-Liebknecht-Str. 24-25, 14476, Potsdam, Germany
| | - Andreas Herrmann
- Institute for Biology, IRI Life Science, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115, Berlin, Germany.
| | - Roland Schwarzer
- Institute for Biology, IRI Life Science, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115, Berlin, Germany. .,Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel. .,Gladstone Institute of Virology and Immunology, 1650 Owens Street, San Francisco, CA, 95158, USA.
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34
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Molecular aspects of Rift Valley fever virus and the emergence of reassortants. Virus Genes 2018; 55:1-11. [PMID: 30426314 DOI: 10.1007/s11262-018-1611-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 11/03/2018] [Indexed: 10/27/2022]
Abstract
Rift Valley fever phlebovirus (RVFV) is a mosquito-transmitted pathogen endemic to sub-Saharan Africa and the Arabian Peninsula. RVFV is a threat to both animal and human health and has costly economic consequences mainly related to livestock production and trade. Competent hosts and vectors for RVFV are widespread, existing outside of endemic countries including the USA. Thus, the possibility of RVFV spreading to the USA or other countries worldwide is of significant concern. RVFV (genus Phlebovirus) is comprised of an enveloped virion containing a three-segmented, negative-stranded RNA genome that is able to undergo genetic reassortment. Reassortment has the potential to produce viruses that are more pathogenic, easily transmissible, and that have wider vector or host range. This is especially concerning because of the wide use of live attenuated vaccine strains throughout endemic countries. This review focuses on the molecular aspects of RVFV, genetic diversity of RVFV strains, and RVFV reassortment.
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35
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Punch EK, Hover S, Blest HTW, Fuller J, Hewson R, Fontana J, Mankouri J, Barr JN. Potassium is a trigger for conformational change in the fusion spike of an enveloped RNA virus. J Biol Chem 2018; 293:9937-9944. [PMID: 29678879 PMCID: PMC6028977 DOI: 10.1074/jbc.ra118.002494] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 04/11/2018] [Indexed: 01/23/2023] Open
Abstract
Many enveloped viruses enter cells through the endocytic network, from which they must subsequently escape through fusion of viral and endosomal membranes. This membrane fusion is mediated by virus-encoded spikes that respond to the dynamic endosomal environment, which triggers conformational changes in the spikes that initiate the fusion process. Several fusion triggers have been identified and include pH, membrane composition, and endosome-resident proteins, and these cues dictate when and where viral fusion occurs. We recently reported that infection with an enveloped bunyavirus requires elevated potassium ion concentrations [K+], controlled by cellular K+ channels, that are encountered during viral transit through maturing endosomes. Here we reveal the molecular basis for the K+ requirement of bunyaviruses through the first direct visualization of a member of the Nairoviridae family, namely Hazara virus (HAZV), using cryo-EM. Using cryo-electron tomography, we observed HAZV spike glycoproteins within infectious HAZV particles exposed to both high and low [K+], which showed that exposure to K+ alone results in dramatic changes to the ultrastructural architecture of the virion surface. In low [K+], the spikes adopted a compact conformation arranged in locally ordered arrays, whereas, following exposure to high [K+], the spikes became extended, and spike–membrane interactions were observed. Viruses exposed to high [K+] also displayed enhanced infectivity, thus identifying K+ as a newly defined trigger that helps promote viral infection. Finally, we confirmed that K+ channel blockers are inhibitory to HAZV infection, highlighting the potential of K+ channels as anti-bunyavirus targets.
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Affiliation(s)
- Emma K Punch
- From the School of Molecular and Cellular Biology and
| | | | | | - Jack Fuller
- From the School of Molecular and Cellular Biology and.,the National Infection Service, Public Health England, Porton Down, Salisbury SP4 0JG, United Kingdom
| | - Roger Hewson
- the National Infection Service, Public Health England, Porton Down, Salisbury SP4 0JG, United Kingdom
| | - Juan Fontana
- From the School of Molecular and Cellular Biology and.,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, United Kingdom and
| | - Jamel Mankouri
- From the School of Molecular and Cellular Biology and.,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, United Kingdom and
| | - John N Barr
- From the School of Molecular and Cellular Biology and .,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, United Kingdom and
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36
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Guardado-Calvo P, Atkovska K, Jeffers SA, Grau N, Backovic M, Pérez-Vargas J, de Boer SM, Tortorici MA, Pehau-Arnaudet G, Lepault J, England P, Rottier PJ, Bosch BJ, Hub JS, Rey FA. A glycerophospholipid-specific pocket in the RVFV class II fusion protein drives target membrane insertion. Science 2018; 358:663-667. [PMID: 29097548 DOI: 10.1126/science.aal2712] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 07/20/2017] [Accepted: 09/25/2017] [Indexed: 12/19/2022]
Abstract
The Rift Valley fever virus (RVFV) is transmitted by infected mosquitoes, causing severe disease in humans and livestock across Africa. We determined the x-ray structure of the RVFV class II fusion protein Gc in its postfusion form and in complex with a glycerophospholipid (GPL) bound in a conserved cavity next to the fusion loop. Site-directed mutagenesis and molecular dynamics simulations further revealed a built-in motif allowing en bloc insertion of the fusion loop into membranes, making few nonpolar side-chain interactions with the aliphatic moiety and multiple polar interactions with lipid head groups upon membrane restructuring. The GPL head-group recognition pocket is conserved in the fusion proteins of other arthropod-borne viruses, such as Zika and chikungunya viruses, which have recently caused major epidemics worldwide.
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Affiliation(s)
- P Guardado-Calvo
- Institut Pasteur, Département de Virologie, Unité de Virologie Structurale, 75724 Paris Cedex 15, France. .,UMR 3569 Virologie, CNRS-Institut Pasteur, 25-28 Rue du Docteur Roux, 75015 Paris, France
| | - K Atkovska
- Institute for Microbiology and Genetics, University of Goettingen, Justus-von-Liebig weg 11, 37077 Göttingen, Germany
| | - S A Jeffers
- Institut Pasteur, Département de Virologie, Unité de Virologie Structurale, 75724 Paris Cedex 15, France.,UMR 3569 Virologie, CNRS-Institut Pasteur, 25-28 Rue du Docteur Roux, 75015 Paris, France
| | - N Grau
- Institut Pasteur, Département de Virologie, Unité de Virologie Structurale, 75724 Paris Cedex 15, France.,UMR 3569 Virologie, CNRS-Institut Pasteur, 25-28 Rue du Docteur Roux, 75015 Paris, France
| | - M Backovic
- Institut Pasteur, Département de Virologie, Unité de Virologie Structurale, 75724 Paris Cedex 15, France.,UMR 3569 Virologie, CNRS-Institut Pasteur, 25-28 Rue du Docteur Roux, 75015 Paris, France
| | - J Pérez-Vargas
- Institut Pasteur, Département de Virologie, Unité de Virologie Structurale, 75724 Paris Cedex 15, France.,UMR 3569 Virologie, CNRS-Institut Pasteur, 25-28 Rue du Docteur Roux, 75015 Paris, France
| | - S M de Boer
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
| | - M A Tortorici
- Institut Pasteur, Département de Virologie, Unité de Virologie Structurale, 75724 Paris Cedex 15, France.,UMR 3569 Virologie, CNRS-Institut Pasteur, 25-28 Rue du Docteur Roux, 75015 Paris, France
| | - G Pehau-Arnaudet
- UMR 3528, CNRS, Institut Pasteur, 25-28 rue du Docteur Roux, 75015 Paris, France
| | - J Lepault
- Institut de Biologie Intégrative de la Cellule, CNRS (UMR 9198), Gif-sur-Yvette, France
| | - P England
- UMR 3528, CNRS, Institut Pasteur, 25-28 rue du Docteur Roux, 75015 Paris, France.,Proteopole, Plateforme de Biophysique des Macromolécules et de leurs Interactions (PFBMI), Institut Pasteur, 25-28 rue du Dr Roux, F-75724 Paris Cedex 15, France
| | - P J Rottier
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
| | - B J Bosch
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands
| | - J S Hub
- Institute for Microbiology and Genetics, University of Goettingen, Justus-von-Liebig weg 11, 37077 Göttingen, Germany.
| | - F A Rey
- Institut Pasteur, Département de Virologie, Unité de Virologie Structurale, 75724 Paris Cedex 15, France. .,UMR 3569 Virologie, CNRS-Institut Pasteur, 25-28 Rue du Docteur Roux, 75015 Paris, France
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37
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Abstract
Rift Valley fever (RVF) is a zoonotic mosquito-borne bunyaviral disease associated with high abortion rates, neonatal deaths, and fetal malformations in ruminants, and mild to severe disease in humans. Outbreaks of RVF cause huge economic losses and public health impacts in endemic countries in Africa and the Arabian Peninsula. A proper vaccination strategy is important for preventing or minimizing outbreaks. Vaccination against RVF is not practiced in many countries, however, due to absence or irregular occurrences of outbreaks, despite serological evidence of RVF viral activity. Nonetheless, effective vaccination strategies, and functional national and international multi-disciplinary networks, remain crucial for ensuring availability of vaccines and supporting execution of vaccination in high risk areas for efficient response to RVF alerts and outbreaks.
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Affiliation(s)
| | - Baratang A Lubisi
- Onderstepoort Veterinary Institute, Onderstepoort, Pretoria, South Africa
| | - Tetsuro Ikegami
- Department of Pathology, The University of Texas Medical Branch, Galveston, TX, USA; Sealy Center for Vaccine Development, The University of Texas Medical Branch, Galveston, TX, USA; Center for Biodefense and Emerging Infectious Diseases, The University of Texas Medical Branch, Galveston, TX, USA.
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38
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Halldorsson S, Li S, Li M, Harlos K, Bowden TA, Huiskonen JT. Shielding and activation of a viral membrane fusion protein. Nat Commun 2018; 9:349. [PMID: 29367607 PMCID: PMC5783950 DOI: 10.1038/s41467-017-02789-2] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 12/28/2017] [Indexed: 11/23/2022] Open
Abstract
Entry of enveloped viruses relies on insertion of hydrophobic residues of the viral fusion protein into the host cell membrane. However, the intermediate conformations during fusion remain unknown. Here, we address the fusion mechanism of Rift Valley fever virus. We determine the crystal structure of the Gn glycoprotein and fit it with the Gc fusion protein into cryo-electron microscopy reconstructions of the virion. Our analysis reveals how the Gn shields the hydrophobic fusion loops of the Gc, preventing premature fusion. Electron cryotomography of virions interacting with membranes under acidic conditions reveals how the fusogenic Gc is activated upon removal of the Gn shield. Repositioning of the Gn allows extension of Gc and insertion of fusion loops in the outer leaflet of the target membrane. These data show early structural transitions that enveloped viruses undergo during host cell entry and indicate that analogous shielding mechanisms are utilized across diverse virus families. Viral fusion proteins undergo extensive conformational changes during entry but intermediate conformations often remain unknown. Here, the authors show how Gn of Rift Valley fever virus fusion protein shields hydrophobic fusion loops of Gc and how these loops embed in the target membrane at acidic conditions.
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Affiliation(s)
- Steinar Halldorsson
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN, UK
| | - Sai Li
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN, UK
| | - Mengqiu Li
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN, UK
| | - Karl Harlos
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN, UK
| | - Thomas A Bowden
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN, UK.
| | - Juha T Huiskonen
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN, UK. .,Helsinki Institute of Life Science and Faculty of Environmental and Biological Sciences, University of Helsinki, Viikinkaari 1, Helsinki, 00014, Finland.
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39
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Abstract
Our understanding of the viral world changed just after the first structures of icosahedral viral particles were unveiled. The structural similarities between capsid proteins of distant viral groups were not anticipated, and the findings suggested the existence of common ancestors for viruses with different host range, genomic structure and multiplication strategies. This way, diverse viruses with icosahedral particles can now be grouped based on the structural homology between their capsid proteins. In the last years, the presence of conserved folds between viral proteins in non-icosahedral viruses has also emerged. Viral particles with radically different morphologies, ranging from naked and filamentous to enveloped and pleomorphic, have shown structural homology between the nucleoproteins that bind directly to their genomes. This chapter overviews recent findings regarding the similar structure found between nucleoproteins of eukaryotic ssRNA viruses. The structural homology includes the coat proteins from all known families of flexible filamentous plant viruses, a group with monopartite (+)ssRNA genomes. Their coat proteins share a core domain with nucleoproteins of previously unrelated families of enveloped viruses that have segmented (-)ssRNA genomes. This last group consists of mostly animals viruses, including influenza virus.
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Affiliation(s)
- Mikel Valle
- Molecular Recognition and Host-Pathogen Interactions, Center for Cooperative Research in Biosciences, CIC bioGUNE, Derio, Spain.
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40
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The Postfusion Structure of the Heartland Virus Gc Glycoprotein Supports Taxonomic Separation of the Bunyaviral Families Phenuiviridae and Hantaviridae. J Virol 2017; 92:JVI.01558-17. [PMID: 29070692 DOI: 10.1128/jvi.01558-17] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 10/17/2017] [Indexed: 11/20/2022] Open
Abstract
Heartland virus (HRTV) is an emerging human pathogen that belongs to the newly defined family Phenuiviridae, order Bunyavirales Gn and Gc are two viral surface glycoproteins encoded by the M segment and are required for early events during infection. HRTV delivers its genome into the cytoplasm by fusion of the viral envelope and endosomal membranes under low-pH conditions. Here, we describe the crystal structure of HRTV Gc in its postfusion conformation. The structure shows that Gc displays a typical class II fusion protein conformation, and the overall structure is identical to severe fever with thrombocytopenia syndrome virus (SFTSV) Gc, which also belongs to the Phenuiviridae family. However, our structural analysis indicates that the hantavirus Gc presents distinct features in the aspects of subdomain orientation, N-linked glycosylation, the interaction pattern between protomers, and the fusion loop conformation. This suggests their family-specific subunit arrangement during the fusogenic process and supports the recent taxonomic revision of bunyaviruses. Our results provide insights into the comprehensive comparison of class II membrane fusion proteins in two bunyavirus families, yielding valuable information for treatments against these human pathogens.IMPORTANCE HRTV is an insect-borne virus found in America that can infect humans. It belongs to the newly defined family Phenuiviridae, order Bunyavirales HRTV contains three single-stranded RNA segments (L, M, and S). The M segment of the virus encodes a polyprotein precursor that is cleaved into two glycoproteins, Gn and Gc. Gc is a fusion protein facilitating virus entry into host cells. Here, we report the crystal structure of the HRTV Gc protein. The structure displays a typical class II fusion protein conformation. Comparison of HRTV Gc with a recently solved structure of another bunyavirus Gc revealed that these Gc structures display a newly defined family specificity, supporting the recent International Committee on Taxonomy of Viruses reclassification of the bunyaviruses. Our results expand the knowledge of bunyavirus fusion proteins and help us to understand bunyavirus characterizations. This study provides useful information to improve protection against and therapies for bunyavirus infections.
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41
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Atkins C, Freiberg AN. Recent advances in the development of antiviral therapeutics for Rift Valley fever virus infection. Future Virol 2017; 12:651-665. [PMID: 29181086 DOI: 10.2217/fvl-2017-0060] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 07/26/2017] [Indexed: 12/25/2022]
Abstract
Rift Valley fever virus (RVFV) is a mosquito-borne bunyavirus endemic to sub-Saharan Africa and the Arabian Peninsula and the etiological agent of Rift Valley fever. Rift Valley fever is a disease of major public health and economic concern, affecting livestock and humans. In ruminants, RVFV infection is characterized by high mortality rates in newborns and near 100% abortion rates in pregnant animals. Infection in humans is typically manifested as a self-limiting febrile illness, but can lead to severe and fatal hepatitis, encephalitis, hemorrhagic fever or retinitis with partial or complete blindness. Currently, there are no specific treatment options available for RVFV infection. This review presents a summary of the therapeutic approaches that have been explored on the treatment of RVFV infection.
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Affiliation(s)
- Colm Atkins
- Department of Pathology, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA.,Department of Pathology, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA
| | - Alexander N Freiberg
- Department of Pathology, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA.,The Sealy Center for Vaccine Development, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA.,The Center for Biodefense & Emerging Infectious Diseases, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA.,Department of Pathology, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA.,The Sealy Center for Vaccine Development, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA.,The Center for Biodefense & Emerging Infectious Diseases, The University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555, USA
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42
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Structural Transitions of the Conserved and Metastable Hantaviral Glycoprotein Envelope. J Virol 2017; 91:JVI.00378-17. [PMID: 28835498 PMCID: PMC5640846 DOI: 10.1128/jvi.00378-17] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 08/10/2017] [Indexed: 01/13/2023] Open
Abstract
Hantaviruses are zoonotic pathogens that cause severe hemorrhagic fever and pulmonary syndrome. The outer membrane of the hantavirus envelope displays a lattice of two glycoproteins, Gn and Gc, which orchestrate host cell recognition and entry. Here, we describe the crystal structure of the Gn glycoprotein ectodomain from the Asiatic Hantaan virus (HTNV), the most prevalent pathogenic hantavirus. Structural overlay analysis reveals that the HTNV Gn fold is highly similar to the Gn of Puumala virus (PUUV), a genetically and geographically distinct and less pathogenic hantavirus found predominantly in northeastern Europe, confirming that the hantaviral Gn fold is architecturally conserved across hantavirus clades. Interestingly, HTNV Gn crystallized at acidic pH, in a compact tetrameric configuration distinct from the organization at neutral pH. Analysis of the Gn, both in solution and in the context of the virion, confirms the pH-sensitive oligomeric nature of the glycoprotein, indicating that the hantaviral Gn undergoes structural transitions during host cell entry. These data allow us to present a structural model for how acidification during endocytic uptake of the virus triggers the dissociation of the metastable Gn-Gc lattice to enable insertion of the Gc-resident hydrophobic fusion loops into the host cell membrane. Together, these data reveal the dynamic plasticity of the structurally conserved hantaviral surface. IMPORTANCE Although outbreaks of Korean hemorrhagic fever were first recognized during the Korean War (1950 to 1953), it was not until 1978 that they were found to be caused by Hantaan virus (HTNV), the most prevalent pathogenic hantavirus. Here, we describe the crystal structure of HTNV envelope glycoprotein Gn, an integral component of the Gn-Gc glycoprotein spike complex responsible for host cell entry. HTNV Gn is structurally conserved with the Gn of a genetically and geographically distal hantavirus, Puumala virus, indicating that the observed α/β fold is well preserved across the Hantaviridae family. The combination of our crystal structure with solution state analysis of recombinant protein and electron cryo-microscopy of acidified hantavirus allows us to propose a model for endosome-induced reorganization of the hantaviral glycoprotein lattice. This provides a molecular-level rationale for the exposure of the hydrophobic fusion loops on the Gc, a process required for fusion of viral and cellular membranes.
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43
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Zamora M, Méndez-López E, Agirrezabala X, Cuesta R, Lavín JL, Sánchez-Pina MA, Aranda MA, Valle M. Potyvirus virion structure shows conserved protein fold and RNA binding site in ssRNA viruses. SCIENCE ADVANCES 2017; 3:eaao2182. [PMID: 28948231 PMCID: PMC5606705 DOI: 10.1126/sciadv.aao2182] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 08/18/2017] [Indexed: 05/16/2023]
Abstract
Potyviruses constitute the second largest genus of plant viruses and cause important economic losses in a large variety of crops; however, the atomic structure of their particles remains unknown. Infective potyvirus virions are long flexuous filaments where coat protein (CP) subunits assemble in helical mode bound to a monopartite positive-sense single-stranded RNA [(+)ssRNA] genome. We present the cryo-electron microscopy (cryoEM) structure of the potyvirus watermelon mosaic virus at a resolution of 4.0 Å. The atomic model shows a conserved fold for the CPs of flexible filamentous plant viruses, including a universally conserved RNA binding pocket, which is a potential target for antiviral compounds. This conserved fold of the CP is widely distributed in eukaryotic viruses and is also shared by nucleoproteins of enveloped viruses with segmented (-)ssRNA (negative-sense ssRNA) genomes, including influenza viruses.
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Affiliation(s)
- Miguel Zamora
- Molecular Recognition and Host-Pathogen Interactions, Center for Cooperative Research in Biosciences, CIC bioGUNE, 48160 Derio, Spain
| | - Eduardo Méndez-López
- Centro de Edafología y Biología Aplicada del Segura (CEBAS), Consejo Superior de Investigaciones Científicas (CSIC), Espinardo, 30100 Murcia, Spain
| | - Xabier Agirrezabala
- Molecular Recognition and Host-Pathogen Interactions, Center for Cooperative Research in Biosciences, CIC bioGUNE, 48160 Derio, Spain
| | - Rebeca Cuesta
- Molecular Recognition and Host-Pathogen Interactions, Center for Cooperative Research in Biosciences, CIC bioGUNE, 48160 Derio, Spain
| | - José L. Lavín
- Molecular Recognition and Host-Pathogen Interactions, Center for Cooperative Research in Biosciences, CIC bioGUNE, 48160 Derio, Spain
| | - M. Amelia Sánchez-Pina
- Centro de Edafología y Biología Aplicada del Segura (CEBAS), Consejo Superior de Investigaciones Científicas (CSIC), Espinardo, 30100 Murcia, Spain
| | - Miguel A. Aranda
- Centro de Edafología y Biología Aplicada del Segura (CEBAS), Consejo Superior de Investigaciones Científicas (CSIC), Espinardo, 30100 Murcia, Spain
| | - Mikel Valle
- Molecular Recognition and Host-Pathogen Interactions, Center for Cooperative Research in Biosciences, CIC bioGUNE, 48160 Derio, Spain
- Corresponding author.
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44
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Abstract
The Bunyavirales Order encompasses nine families of enveloped viruses containing a single-stranded negative-sense RNA genome divided into three segments. The small (S) and large (L) segments encode proteins participating in genome replication in the infected cell cytoplasm. The middle (M) segment encodes the viral glycoproteins Gn and Gc, which are derived from a precursor polyprotein by host cell proteases. Entry studies are available only for a few viruses in the Order, and in each case they were shown to enter cells via receptor-mediated endocytosis. The acidic endosomal pH triggers the fusion of the viral envelope with the membrane of an endosome. Structural studies on two members of this Order, the phleboviruses and the hantaviruses, have shown that the membrane fusion protein Gc displays a class II fusion protein fold and is homologous to its counterparts in flaviviruses and alphaviruses, which are positive-sense, single-stranded RNA viruses. We analyze here recent data on the structure and function of the structure of the phlebovirus Gc and hantavirus Gn and Gc glycoproteins, and extrapolate common features identified in the amino acid sequences to understand also the structure and function of their counterparts in other families of the Bunyavirales Order. Our analysis also identified clear structural homology between the hantavirus Gn and alphavirus E2 glycoproteins, which make a heterodimer with the corresponding fusion proteins Gc and E1, respectively, revealing that not only the fusion protein has been conserved across viral families.
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Affiliation(s)
- Pablo Guardado-Calvo
- Institut Pasteur, Unité de Virologie Structurale, Paris Cedex 15, France; CNRS UMR 3569 Virologie, Paris Cedex 15, France
| | - Félix A Rey
- Institut Pasteur, Unité de Virologie Structurale, Paris Cedex 15, France; CNRS UMR 3569 Virologie, Paris Cedex 15, France.
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45
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The Role of Phlebovirus Glycoproteins in Viral Entry, Assembly and Release. Viruses 2016; 8:v8070202. [PMID: 27455305 PMCID: PMC4974537 DOI: 10.3390/v8070202] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 07/13/2016] [Accepted: 07/14/2016] [Indexed: 01/08/2023] Open
Abstract
Bunyaviruses are enveloped viruses with a tripartite RNA genome that can pose a serious threat to animal and human health. Members of the Phlebovirus genus of the family Bunyaviridae are transmitted by mosquitos and ticks to humans and include highly pathogenic agents like Rift Valley fever virus (RVFV) and severe fever with thrombocytopenia syndrome virus (SFTSV) as well as viruses that do not cause disease in humans, like Uukuniemi virus (UUKV). Phleboviruses and other bunyaviruses use their envelope proteins, Gn and Gc, for entry into target cells and for assembly of progeny particles in infected cells. Thus, binding of Gn and Gc to cell surface factors promotes viral attachment and uptake into cells and exposure to endosomal low pH induces Gc-driven fusion of the viral and the vesicle membranes. Moreover, Gn and Gc facilitate virion incorporation of the viral genome via their intracellular domains and Gn and Gc interactions allow the formation of a highly ordered glycoprotein lattice on the virion surface. Studies conducted in the last decade provided important insights into the configuration of phlebovirus Gn and Gc proteins in the viral membrane, the cellular factors used by phleboviruses for entry and the mechanisms employed by phlebovirus Gc proteins for membrane fusion. Here, we will review our knowledge on the glycoprotein biogenesis and the role of Gn and Gc proteins in the phlebovirus replication cycle.
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46
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Structure of a phleboviral envelope glycoprotein reveals a consolidated model of membrane fusion. Proc Natl Acad Sci U S A 2016; 113:7154-9. [PMID: 27325770 DOI: 10.1073/pnas.1603827113] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
An emergent viral pathogen termed severe fever with thrombocytopenia syndrome virus (SFTSV) is responsible for thousands of clinical cases and associated fatalities in China, Japan, and South Korea. Akin to other phleboviruses, SFTSV relies on a viral glycoprotein, Gc, to catalyze the merger of endosomal host and viral membranes during cell entry. Here, we describe the postfusion structure of SFTSV Gc, revealing that the molecular transformations the phleboviral Gc undergoes upon host cell entry are conserved with otherwise unrelated alpha- and flaviviruses. By comparison of SFTSV Gc with that of the prefusion structure of the related Rift Valley fever virus, we show that these changes involve refolding of the protein into a trimeric state. Reverse genetics and rescue of site-directed histidine mutants enabled localization of histidines likely to be important for triggering this pH-dependent process. These data provide structural and functional evidence that the mechanism of phlebovirus-host cell fusion is conserved among genetically and patho-physiologically distinct viral pathogens.
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47
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Albornoz A, Hoffmann AB, Lozach PY, Tischler ND. Early Bunyavirus-Host Cell Interactions. Viruses 2016; 8:v8050143. [PMID: 27213430 PMCID: PMC4885098 DOI: 10.3390/v8050143] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 05/15/2016] [Indexed: 12/12/2022] Open
Abstract
The Bunyaviridae is the largest family of RNA viruses, with over 350 members worldwide. Several of these viruses cause severe diseases in livestock and humans. With an increasing number and frequency of outbreaks, bunyaviruses represent a growing threat to public health and agricultural productivity globally. Yet, the receptors, cellular factors and endocytic pathways used by these emerging pathogens to infect cells remain largely uncharacterized. The focus of this review is on the early steps of bunyavirus infection, from virus binding to penetration from endosomes. We address current knowledge and advances for members from each genus in the Bunyaviridae family regarding virus receptors, uptake, intracellular trafficking and fusion.
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Affiliation(s)
- Amelina Albornoz
- Molecular Virology Laboratory, Fundación Ciencia & Vida, Av. Zañartu 1482, 7780272 Santiago, Chile.
| | - Anja B Hoffmann
- CellNetworks-Cluster of Excellence and Department of Infectious Diseases, Virology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany.
| | - Pierre-Yves Lozach
- CellNetworks-Cluster of Excellence and Department of Infectious Diseases, Virology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany.
| | - Nicole D Tischler
- Molecular Virology Laboratory, Fundación Ciencia & Vida, Av. Zañartu 1482, 7780272 Santiago, Chile.
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48
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Léger P, Tetard M, Youness B, Cordes N, Rouxel RN, Flamand M, Lozach PY. Differential Use of the C-Type Lectins L-SIGN and DC-SIGN for Phlebovirus Endocytosis. Traffic 2016; 17:639-56. [PMID: 26990254 DOI: 10.1111/tra.12393] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 03/08/2016] [Accepted: 03/09/2016] [Indexed: 12/21/2022]
Abstract
Bunyaviruses represent a growing threat to humans and livestock globally. The receptors, cellular factors and endocytic pathways used by these emerging pathogens to infect cells remain largely unidentified and poorly characterized. DC-SIGN is a C-type lectin highly expressed on dermal dendritic cells that has been found to act as an authentic entry receptor for many phleboviruses (Bunyaviridae), including Rift Valley fever virus (RVFV), Toscana virus (TOSV) and Uukuniemi virus (UUKV). We found that these phleboviruses can exploit another C-type lectin, L-SIGN, for infection. L-SIGN shares 77% sequence homology with DC-SIGN and is expressed on liver sinusoidal endothelial cells. L-SIGN is required for UUKV binding but not for virus internalization. An endocytosis-defective mutant of L-SIGN was still able to mediate virus uptake and infection, indicating that L-SIGN acts as an attachment receptor for phleboviruses rather than an endocytic receptor. Our results point out a fundamental difference in the use of the C-type lectins L-SIGN and DC-SIGN by UUKV to enter cells, although both proteins are closely related in terms of molecular structure and biological function. This study sheds new light on the molecular mechanisms by which phleboviruses target the liver and also highlights the added complexity in virus-receptor interactions beyond attachment.
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Affiliation(s)
- Psylvia Léger
- CellNetworks - Cluster of Excellence and Department of Infectious Diseases, Virology, University Hospital Heidelberg, Heidelberg, Germany
| | - Marilou Tetard
- INRS-Institut Armand-Frappier, Laval, Canada.,Current address: Inserm UMR_S1134, Paris, France
| | - Berthe Youness
- CellNetworks - Cluster of Excellence and Department of Infectious Diseases, Virology, University Hospital Heidelberg, Heidelberg, Germany.,INRS-Institut Armand-Frappier, Laval, Canada.,Reproduction Genetics Unit, Department of Gynecological Endocrinology and Reproductive Medicine, University Hospital, Heidelberg, Germany
| | - Nicole Cordes
- CellNetworks - Cluster of Excellence and Department of Infectious Diseases, Virology, University Hospital Heidelberg, Heidelberg, Germany
| | - Ronan N Rouxel
- INRS-Institut Armand-Frappier, Laval, Canada.,UR_0892 Unité de Virologie et Immunologie Moléculaire, INRA, CRJ, Jouy-en-Josas, France
| | - Marie Flamand
- Structural Virology, Institut Pasteur, Paris, France
| | - Pierre-Yves Lozach
- CellNetworks - Cluster of Excellence and Department of Infectious Diseases, Virology, University Hospital Heidelberg, Heidelberg, Germany.,INRS-Institut Armand-Frappier, Laval, Canada
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49
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Bitto D, Halldorsson S, Caputo A, Huiskonen JT. Low pH and Anionic Lipid-dependent Fusion of Uukuniemi Phlebovirus to Liposomes. J Biol Chem 2016; 291:6412-22. [PMID: 26811337 PMCID: PMC4813561 DOI: 10.1074/jbc.m115.691113] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Indexed: 12/14/2022] Open
Abstract
Many phleboviruses (family Bunyaviridae) are emerging as medically important viruses. These viruses enter target cells by endocytosis and low pH-dependent membrane fusion in late endosomes. However, the necessary and sufficient factors for fusion have not been fully characterized. We have studied the minimal fusion requirements of a prototypic phlebovirus, Uukuniemi virus, in an in vitro virus-liposome assay. We show that efficient lipid mixing between viral and liposome membranes requires close to physiological temperatures and phospholipids with negatively charged headgroups, such as the late endosomal phospholipid bis(monoacylglycero)phosphate. We further demonstrate that bis(monoacylglycero)phosphate increases Uukuniemi virus fusion beyond the lipid mixing stage. By using electron cryotomography of viral particles in the presence or absence of liposomes, we observed that the conformation of phlebovirus glycoprotein capsomers changes from the native conformation toward a more elongated conformation at a fusion permissive pH. Our results suggest a rationale for phlebovirus entry in late endosomes.
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Affiliation(s)
- David Bitto
- From the Division of Structural Biology, Wellcome Trust Centre for Human Genetics, Roosevelt Drive, University of Oxford, Oxford OX3 7BN, United Kingdom
| | - Steinar Halldorsson
- From the Division of Structural Biology, Wellcome Trust Centre for Human Genetics, Roosevelt Drive, University of Oxford, Oxford OX3 7BN, United Kingdom
| | - Alessandro Caputo
- From the Division of Structural Biology, Wellcome Trust Centre for Human Genetics, Roosevelt Drive, University of Oxford, Oxford OX3 7BN, United Kingdom
| | - Juha T Huiskonen
- From the Division of Structural Biology, Wellcome Trust Centre for Human Genetics, Roosevelt Drive, University of Oxford, Oxford OX3 7BN, United Kingdom
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50
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Agirrezabala X, Méndez-López E, Lasso G, Sánchez-Pina MA, Aranda M, Valle M. The near-atomic cryoEM structure of a flexible filamentous plant virus shows homology of its coat protein with nucleoproteins of animal viruses. eLife 2015; 4:e11795. [PMID: 26673077 PMCID: PMC4739775 DOI: 10.7554/elife.11795] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 12/15/2015] [Indexed: 11/23/2022] Open
Abstract
Flexible filamentous viruses include economically important plant pathogens. Their viral particles contain several hundred copies of a helically arrayed coat protein (CP) protecting a (+)ssRNA. We describe here a structure at 3.9 Å resolution, from electron cryomicroscopy, of Pepino mosaic virus (PepMV), a representative of the genus Potexvirus (family Alphaflexiviridae). Our results allow modeling of the CP and its interactions with viral RNA. The overall fold of PepMV CP resembles that of nucleoproteins (NPs) from the genus Phlebovirus (family Bunyaviridae), a group of enveloped (-)ssRNA viruses. The main difference between potexvirus CP and phlebovirus NP is in their C-terminal extensions, which appear to determine the characteristics of the distinct multimeric assemblies – a flexuous, helical rod or a loose ribonucleoprotein. The homology suggests gene transfer between eukaryotic (+) and (-)ssRNA viruses. DOI:http://dx.doi.org/10.7554/eLife.11795.001 A group of “flexible filamentous” viruses can cause serious diseases in a wide variety of crops and other plants. Each virus particle contains a single molecule called ribonucleic acid (RNA), which is protected by hundreds of copies of a coat protein. The RNA and coat proteins are arranged in a helical fashion to make a flexible rod-shaped particle. The flexibility of these viruses makes it difficult to carry out in-depth studies of their three-dimensional structures. As a result, we do not know how the RNA and coat proteins interact to form the structure of each virus particle. Agirrezabala et al. used a technique called cryo-electron microscopy (or cryoEM for short) to generate a highly detailed three-dimensional model of a flexible filamentous virus called Pepino Mosaic Virus. Agirezabala et al.’s findings reveal how the virus particles assemble, and the interactions between the coat protein and the ssRNA. Unexpectedly, the structure of the coat protein from Pepino Mosiac Virus is very similar to the structure of “nucleoproteins” from a group of viruses called the Phleboviruses, which infect animals. This similarity is striking and suggests that the gene that encodes these proteins has been transferred between the two groups of viruses during evolution. A future challenge is to find out whether this similarity extends to other groups of viruses. DOI:http://dx.doi.org/10.7554/eLife.11795.002
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Affiliation(s)
- Xabier Agirrezabala
- Structural Biology Unit, Center for Cooperative Research in Biosciences, Derio, Spain
| | - Eduardo Méndez-López
- Centro de Edafología y Biología Aplicada del Segura, Murcia, Spain.,Consejo Superior de Investigaciones Científicas, Murcia, Spain
| | - Gorka Lasso
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, United States
| | - M Amelia Sánchez-Pina
- Centro de Edafología y Biología Aplicada del Segura, Murcia, Spain.,Consejo Superior de Investigaciones Científicas, Murcia, Spain
| | - Miguel Aranda
- Centro de Edafología y Biología Aplicada del Segura, Murcia, Spain.,Consejo Superior de Investigaciones Científicas, Murcia, Spain
| | - Mikel Valle
- Structural Biology Unit, Center for Cooperative Research in Biosciences, Derio, Spain
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