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Guevara-Vega M, Andrade BS, Palmeira LS, Bernardino SS, Taveira EB, Cardoso-Sousa L, Caixeta DC, Cunha TM, Goulart LR, Jardim ACG, Sabino-Silva R. Chapare virus infection and current perspectives on dentistry. Clin Oral Investig 2024; 28:238. [PMID: 38568249 DOI: 10.1007/s00784-023-05399-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 12/04/2023] [Indexed: 04/05/2024]
Abstract
OBJECTIVES This narrative review addresses relevant points about Chapare virus (CHAV) entry in oral cells, CHAV transmission, and preventive strategies in dental clinical settings. It is critical in dentistry due to the frequent presence of gingival hemorrhage occurred in CHAV-infected patients. MATERIALS AND METHODS Studies related to CHAV were searched in MEDLINE/PubMed, Scopus, EMBASE, and Web-of-Science databases without language restriction or year of publication. RESULTS Recently, the PAHO/WHO and CDC indicate a presence of human-to-human transmission of CHAV associated with direct contact with saliva, blood, or urine, and also through droplets or aerosols created in healthcare procedures. CHAV was detected in human oropharyngeal saliva and gingival bleeding was confirmed in all cases of CHAV hemorrhagic fever, including evidence of nosocomial CHAV transmission in healthcare workers. We revisited the human transferrin receptor 1 (TfR1) expression in oral, nasal, and salivary glands tissues, as well as, we firstly identified the critical residues in the pre-glycoprotein (GP) complex of CHAV that interacts with human TfR1 using cutting-edge in silico bioinformatics platforms associated with molecular dynamic analysis. CONCLUSIONS In this multidisciplinary view, we also point out critical elements to provide perspectives on the preventive strategies for dentists and frontline healthcare workers against CHAV, and in the implementation of salivary diagnostic platforms for virus detection, which can be critical to an urgent plan to prevent human-to-human transmission based on current evidence. CLINICAL RELEVANCE The preventive strategies in dental clinical settings are pivotal due to the aerosol-generating procedures in dentistry with infected patients or suspected cases of CHAV infection.
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Affiliation(s)
- Marco Guevara-Vega
- Innovation Center in Salivary Diagnostics and Nanobiotechnology, Department of Physiology, Institute of Biomedical Sciences, Federal University of Uberlandia, Uberlandia, Minas Gerais, Brazil
- Biomedical Research Group, University of Sucre, Sincelejo, Colombia
| | - Bruno Silva Andrade
- Laboratory of Bioinformatics and Computational Chemistry, Department of Biological Sciences, State University of Southwest of Bahia (UESB), Jequié, Bahia, Brazil.
| | - Lucas Sousa Palmeira
- Laboratory of Bioinformatics and Computational Chemistry, Department of Biological Sciences, State University of Southwest of Bahia (UESB), Jequié, Bahia, Brazil
| | - Sttephany Silva Bernardino
- Innovation Center in Salivary Diagnostics and Nanobiotechnology, Department of Physiology, Institute of Biomedical Sciences, Federal University of Uberlandia, Uberlandia, Minas Gerais, Brazil
| | - Elisa Borges Taveira
- Innovation Center in Salivary Diagnostics and Nanobiotechnology, Department of Physiology, Institute of Biomedical Sciences, Federal University of Uberlandia, Uberlandia, Minas Gerais, Brazil
| | - Leia Cardoso-Sousa
- Innovation Center in Salivary Diagnostics and Nanobiotechnology, Department of Physiology, Institute of Biomedical Sciences, Federal University of Uberlandia, Uberlandia, Minas Gerais, Brazil
| | - Douglas C Caixeta
- Innovation Center in Salivary Diagnostics and Nanobiotechnology, Department of Physiology, Institute of Biomedical Sciences, Federal University of Uberlandia, Uberlandia, Minas Gerais, Brazil
| | - Thulio M Cunha
- Department of Pulmonology, School of Medicine, Federal University of Uberlandia, Uberlandia, Minas Gerais, Brazil
| | - Luiz R Goulart
- Institute of Biotechnology, Federal University of Uberlandia, Uberlandia, Minas Gerais, Brazil
| | - Ana Carolina Gomes Jardim
- Laboratory of Antiviral Research, Institute of Biomedical Sciences, Federal University of Uberlandia, Uberlandia, Minas Gerais, Brazil
| | - Robinson Sabino-Silva
- Innovation Center in Salivary Diagnostics and Nanobiotechnology, Department of Physiology, Institute of Biomedical Sciences, Federal University of Uberlandia, Uberlandia, Minas Gerais, Brazil.
- Innovation Center in Salivary Diagnostic and Nanotheranostics, Institute of Biomedical Sciences (ICBIM), Federal University of Uberlandia (UFU), Av. Pará, 1720, Campus Umuarama, Uberlandia, MG, CEP 38400-902, Brazil.
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2
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Gorzkiewicz M, Cramer J, Xu HC, Lang PA. The role of glycosylation patterns of viral glycoproteins and cell entry receptors in arenavirus infection. Biomed Pharmacother 2023; 166:115196. [PMID: 37586116 DOI: 10.1016/j.biopha.2023.115196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 07/14/2023] [Accepted: 07/18/2023] [Indexed: 08/18/2023] Open
Abstract
Mammarenaviruses are enveloped RNA viruses that can be associated with rodent-transmitted diseases in humans. Their virions are composed of a nucleocapsid surrounded by a lipid bilayer with glycoprotein (GP) spikes interacting with receptors on target cells. Both the GP and receptors are highly glycosylated, with glycosylation patterns being crucial for virus binding and cell entry, viral tropism, immune responses, or therapy strategies. These effects have been previously described for several different viruses. In case of arenaviruses, they remain insufficiently understood. Thus, it is important to determine the mechanisms of glycosylation of viral proteins and receptors responsible for infection, in order to fully understand the biology of arenaviruses. In this article, we have summarized and critically evaluated the available literature data on the glycosylation of mammarenavirus-associated proteins to facilitate further research in this field.
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Affiliation(s)
- Michal Gorzkiewicz
- Department of Molecular Medicine II, Medical Faculty, Heinrich Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany; Department of General Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, 141/143 Pomorska St., 90-236 Lodz, Poland.
| | - Jonathan Cramer
- Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Haifeng C Xu
- Department of Molecular Medicine II, Medical Faculty, Heinrich Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Philipp A Lang
- Department of Molecular Medicine II, Medical Faculty, Heinrich Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany.
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3
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Zhang J, Zhu Y, Wang X, Wang J. 25-hydroxycholesterol: an integrator of antiviral ability and signaling. Front Immunol 2023; 14:1268104. [PMID: 37781400 PMCID: PMC10533924 DOI: 10.3389/fimmu.2023.1268104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 08/29/2023] [Indexed: 10/03/2023] Open
Abstract
Cholesterol, as an important component in mammalian cells, is efficient for viral entry, replication, and assembly. Oxysterols especially hydroxylated cholesterols are recognized as novel regulators of the innate immune response. The antiviral ability of 25HC (25-Hydroxycholesterol) is uncovered due to its role as a metabolic product of the interferon-stimulated gene CH25H (cholesterol-25-hydroxylase). With the advancement of research, the biological functions of 25HC and its structural functions have been interpreted gradually. Furthermore, the underlying mechanisms of antiviral effect of 25HC are not only limited to interferon regulation. Taken up by the special biosynthetic ways and structure, 25HC contributes to modulate not only the cholesterol metabolism but also autophagy and inflammation by regulating signaling pathways. The outcome of modulation by 25HC seems to be largely dependent on the cell types, viruses and context of cell microenvironments. In this paper, we review the recent proceedings on the regulatory effect of 25HC on interferon-independent signaling pathways related to its antiviral capacity and its putative underlying mechanisms.
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Affiliation(s)
- Jialu Zhang
- College of Veterinary Medicine, China Agricultural University, Beijing, China
- College of Veterinary Medicine, Sanya Institute of China Agricultural University, Sanya, China
| | - Yaohong Zhu
- College of Veterinary Medicine, China Agricultural University, Beijing, China
- College of Veterinary Medicine, Sanya Institute of China Agricultural University, Sanya, China
| | - Xiaojia Wang
- College of Veterinary Medicine, China Agricultural University, Beijing, China
- College of Veterinary Medicine, Sanya Institute of China Agricultural University, Sanya, China
| | - Jiufeng Wang
- College of Veterinary Medicine, China Agricultural University, Beijing, China
- College of Veterinary Medicine, Sanya Institute of China Agricultural University, Sanya, China
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4
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Perrett HR, Brouwer PJM, Hurtado J, Newby ML, Liu L, Müller-Kräuter H, Müller Aguirre S, Burger JA, Bouhuijs JH, Gibson G, Messmer T, Schieffelin JS, Antanasijevic A, Boons GJ, Strecker T, Crispin M, Sanders RW, Briney B, Ward AB. Structural conservation of Lassa virus glycoproteins and recognition by neutralizing antibodies. Cell Rep 2023; 42:112524. [PMID: 37209096 PMCID: PMC10242449 DOI: 10.1016/j.celrep.2023.112524] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 03/07/2023] [Accepted: 05/01/2023] [Indexed: 05/22/2023] Open
Abstract
Lassa fever is an acute hemorrhagic fever caused by the zoonotic Lassa virus (LASV). The LASV glycoprotein complex (GPC) mediates viral entry and is the sole target for neutralizing antibodies. Immunogen design is complicated by the metastable nature of recombinant GPCs and the antigenic differences among phylogenetically distinct LASV lineages. Despite the sequence diversity of the GPC, structures of most lineages are lacking. We present the development and characterization of prefusion-stabilized, trimeric GPCs of LASV lineages II, V, and VII, revealing structural conservation despite sequence diversity. High-resolution structures and biophysical characterization of the GPC in complex with GP1-A-specific antibodies suggest their neutralization mechanisms. Finally, we present the isolation and characterization of a trimer-preferring neutralizing antibody belonging to the GPC-B competition group with an epitope that spans adjacent protomers and includes the fusion peptide. Our work provides molecular detail information on LASV antigenic diversity and will guide efforts to design pan-LASV vaccines.
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Affiliation(s)
- Hailee R Perrett
- Department of Integrative, Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Philip J M Brouwer
- Department of Integrative, Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Jonathan Hurtado
- Department of Immunology and Microbiology, Scripps Research, La Jolla, CA 92037, USA; Center for Viral Systems Biology, Scripps Research, La Jolla, CA 92037, USA
| | - Maddy L Newby
- School of Biological Sciences, University of Southampton, Southampton SO17 1BJ, UK
| | - Lin Liu
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | | | | | - Judith A Burger
- Department of Medical Microbiology and Infection Prevention, Amsterdam University Medical Centers. Location AMC, University of Amsterdam, Amsterdam Infection & Immunity Institute, Amsterdam 1105 AZ, the Netherlands
| | - Joey H Bouhuijs
- Department of Medical Microbiology and Infection Prevention, Amsterdam University Medical Centers. Location AMC, University of Amsterdam, Amsterdam Infection & Immunity Institute, Amsterdam 1105 AZ, the Netherlands
| | - Grace Gibson
- Department of Integrative, Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Terrence Messmer
- Department of Immunology and Microbiology, Scripps Research, La Jolla, CA 92037, USA
| | - John S Schieffelin
- Department of Pediatrics, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | - Aleksandar Antanasijevic
- Department of Integrative, Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Geert-Jan Boons
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA; Department of Chemical Biology and Drug Discovery, Utrecht University, Utrecht 3584 CG, the Netherlands
| | - Thomas Strecker
- Institute of Virology, Philipps University Marburg, 35043 Marburg, Germany
| | - Max Crispin
- School of Biological Sciences, University of Southampton, Southampton SO17 1BJ, UK
| | - Rogier W Sanders
- Department of Medical Microbiology and Infection Prevention, Amsterdam University Medical Centers. Location AMC, University of Amsterdam, Amsterdam Infection & Immunity Institute, Amsterdam 1105 AZ, the Netherlands; Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, NY 10021, USA
| | - Bryan Briney
- Department of Immunology and Microbiology, Scripps Research, La Jolla, CA 92037, USA; Center for Viral Systems Biology, Scripps Research, La Jolla, CA 92037, USA
| | - Andrew B Ward
- Department of Integrative, Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
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5
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Dong S, Mao W, Liu Y, Jia X, Zhang Y, Zhou M, Hou Y, Xiao G, Wang W. Deletion of the first glycosylation site promotes Lassa virus glycoprotein-mediated membrane fusion. Virol Sin 2023:S1995-820X(23)00030-5. [PMID: 37059226 DOI: 10.1016/j.virs.2023.04.003] [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: 01/11/2023] [Accepted: 04/10/2023] [Indexed: 04/16/2023] Open
Abstract
The Lassa virus is endemic in West Africa and causes severe hemorrhagic Lassa fever in humans. The glycoprotein complex (GPC) of LASV is highly glycosylation-modified, with 11 N-glycosylation sites. All 11 N-linked glycan chains play critical roles in GPC cleavage, folding, receptor binding, membrane fusion, and immune evasion. In this study, we focused on the first glycosylation site because its deletion mutant (N79Q) results in an unexpected enhanced membrane fusion, whereas it exerts little effect on GPC expression, cleavage, and receptor binding. Meanwhile, the pseudotype virus bearing GPCN79Q was more sensitive to the neutralizing antibody 37.7H and was attenuated in virulence. Exploring the biological functions of the key glycosylation site on LASV GPC will help elucidate the mechanism of LASV infection and provide strategies for the development of attenuated vaccines against LASV infection.
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Affiliation(s)
- Siqi Dong
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430207, China; University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Wenting Mao
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430207, China; University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Yang Liu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430207, China
| | - Xiaoying Jia
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430207, China; University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Yueli Zhang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430207, China; College of Pharmacy and State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, 300071, China
| | - Minmin Zhou
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430207, China; University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Yuxia Hou
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430207, China; University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Gengfu Xiao
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430207, China; University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Wei Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430207, China; University of the Chinese Academy of Sciences, Beijing, 100049, China.
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6
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Brouwer PJM, Antanasijevic A, Ronk AJ, Müller-Kräuter H, Watanabe Y, Claireaux M, Perrett HR, Bijl TPL, Grobben M, Umotoy JC, Schriek AI, Burger JA, Tejjani K, Lloyd NM, Steijaert TH, van Haaren MM, Sliepen K, de Taeye SW, van Gils MJ, Crispin M, Strecker T, Bukreyev A, Ward AB, Sanders RW. Lassa virus glycoprotein nanoparticles elicit neutralizing antibody responses and protection. Cell Host Microbe 2022; 30:1759-1772.e12. [PMID: 36400021 PMCID: PMC9794196 DOI: 10.1016/j.chom.2022.10.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 09/07/2022] [Accepted: 10/25/2022] [Indexed: 11/18/2022]
Abstract
The Lassa virus is endemic in parts of West Africa, and it causes hemorrhagic fever with high mortality. The development of a recombinant protein vaccine has been hampered by the instability of soluble Lassa virus glycoprotein complex (GPC) trimers, which disassemble into monomeric subunits after expression. Here, we use two-component protein nanoparticles consisting of trimeric and pentameric subunits to stabilize GPC in a trimeric conformation. These GPC nanoparticles present twenty prefusion GPC trimers on the surface of an icosahedral particle. Cryo-EM studies of GPC nanoparticles demonstrated a well-ordered structure and yielded a high-resolution structure of an unliganded GPC. These nanoparticles induced potent humoral immune responses in rabbits and protective immunity against the lethal Lassa virus challenge in guinea pigs. Additionally, we isolated a neutralizing antibody that mapped to the putative receptor-binding site, revealing a previously undefined site of vulnerability. Collectively, these findings offer potential approaches to vaccine and therapeutic design for the Lassa virus.
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Affiliation(s)
- Philip J M Brouwer
- Department of Medical Microbiology and Infection Prevention, Amsterdam University Medical Centers, Location AMC, University of Amsterdam, Amsterdam Infection & Immunity Institute, 1105 AZ Amsterdam, the Netherlands; Department of Integrative, Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Aleksandar Antanasijevic
- Department of Integrative, Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA; International AIDS Vaccine Initiative Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Adam J Ronk
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77550, USA; Galveston National Laboratory, University of Texas Medical Branch, Galveston, TX 77550, USA
| | | | - Yasunori Watanabe
- School of Biological Sciences, University of Southampton, Southampton SO17 1BJ, UK
| | - Mathieu Claireaux
- Department of Medical Microbiology and Infection Prevention, Amsterdam University Medical Centers, Location AMC, University of Amsterdam, Amsterdam Infection & Immunity Institute, 1105 AZ Amsterdam, the Netherlands
| | - Hailee R Perrett
- Department of Integrative, Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Tom P L Bijl
- Department of Medical Microbiology and Infection Prevention, Amsterdam University Medical Centers, Location AMC, University of Amsterdam, Amsterdam Infection & Immunity Institute, 1105 AZ Amsterdam, the Netherlands
| | - Marloes Grobben
- Department of Medical Microbiology and Infection Prevention, Amsterdam University Medical Centers, Location AMC, University of Amsterdam, Amsterdam Infection & Immunity Institute, 1105 AZ Amsterdam, the Netherlands
| | - Jeffrey C Umotoy
- Department of Medical Microbiology and Infection Prevention, Amsterdam University Medical Centers, Location AMC, University of Amsterdam, Amsterdam Infection & Immunity Institute, 1105 AZ Amsterdam, the Netherlands
| | - Angela I Schriek
- Department of Medical Microbiology and Infection Prevention, Amsterdam University Medical Centers, Location AMC, University of Amsterdam, Amsterdam Infection & Immunity Institute, 1105 AZ Amsterdam, the Netherlands
| | - Judith A Burger
- Department of Medical Microbiology and Infection Prevention, Amsterdam University Medical Centers, Location AMC, University of Amsterdam, Amsterdam Infection & Immunity Institute, 1105 AZ Amsterdam, the Netherlands
| | - Khadija Tejjani
- Department of Medical Microbiology and Infection Prevention, Amsterdam University Medical Centers, Location AMC, University of Amsterdam, Amsterdam Infection & Immunity Institute, 1105 AZ Amsterdam, the Netherlands
| | - Nicole M Lloyd
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77550, USA; Galveston National Laboratory, University of Texas Medical Branch, Galveston, TX 77550, USA
| | - Thijs H Steijaert
- Department of Medical Microbiology and Infection Prevention, Amsterdam University Medical Centers, Location AMC, University of Amsterdam, Amsterdam Infection & Immunity Institute, 1105 AZ Amsterdam, the Netherlands
| | - Marlies M van Haaren
- Department of Medical Microbiology and Infection Prevention, Amsterdam University Medical Centers, Location AMC, University of Amsterdam, Amsterdam Infection & Immunity Institute, 1105 AZ Amsterdam, the Netherlands
| | - Kwinten Sliepen
- Department of Medical Microbiology and Infection Prevention, Amsterdam University Medical Centers, Location AMC, University of Amsterdam, Amsterdam Infection & Immunity Institute, 1105 AZ Amsterdam, the Netherlands
| | - Steven W de Taeye
- Department of Medical Microbiology and Infection Prevention, Amsterdam University Medical Centers, Location AMC, University of Amsterdam, Amsterdam Infection & Immunity Institute, 1105 AZ Amsterdam, the Netherlands
| | - Marit J van Gils
- Department of Medical Microbiology and Infection Prevention, Amsterdam University Medical Centers, Location AMC, University of Amsterdam, Amsterdam Infection & Immunity Institute, 1105 AZ Amsterdam, the Netherlands
| | - Max Crispin
- School of Biological Sciences, University of Southampton, Southampton SO17 1BJ, UK
| | - Thomas Strecker
- Institute of Virology, Philipps University Marburg, 35043 Marburg, Germany
| | - Alexander Bukreyev
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77550, USA; Galveston National Laboratory, University of Texas Medical Branch, Galveston, TX 77550, USA
| | - Andrew B Ward
- Department of Integrative, Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA; International AIDS Vaccine Initiative Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA 92037, USA.
| | - Rogier W Sanders
- Department of Medical Microbiology and Infection Prevention, Amsterdam University Medical Centers, Location AMC, University of Amsterdam, Amsterdam Infection & Immunity Institute, 1105 AZ Amsterdam, the Netherlands; Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, NY 10021, USA.
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7
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Li H, Buck T, Zandonatti M, Yin J, Moon-Walker A, Fang J, Koval A, Heinrich ML, Rowland MM, Avalos RD, Schendel SL, Parekh D, Zyla D, Enriquez A, Harkins S, Sullivan B, Smith V, Chukwudozie O, Watanabe R, Robinson JE, Garry RF, Branco LM, Hastie KM, Saphire EO. A cocktail of protective antibodies subverts the dense glycan shield of Lassa virus. Sci Transl Med 2022; 14:eabq0991. [PMID: 36288283 PMCID: PMC10084740 DOI: 10.1126/scitranslmed.abq0991] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Developing potent therapeutics and effective vaccines are the ultimate goals in controlling infectious diseases. Lassa virus (LASV), the causative pathogen of Lassa fever (LF), infects hundreds of thousands annually, but effective antivirals or vaccines against LASV infection are still lacking. Furthermore, neutralizing antibodies against LASV are rare. Here, we describe biochemical analyses and high-resolution cryo-electron microscopy structures of a therapeutic cocktail of three broadly protective antibodies that target the LASV glycoprotein complex (GPC), previously identified from survivors of multiple LASV infections. Structural and mechanistic analyses reveal compatible neutralizing epitopes and complementary neutralization mechanisms that offer high potency, broad range, and resistance to escape. These antibodies either circumvent or exploit specific glycans comprising the extensive glycan shield of GPC. Further, they require mammalian glycosylation, native GPC cleavage, and proper GPC trimerization. These findings guided engineering of a next-generation GPC antigen suitable for future neutralizing antibody and vaccine discovery. Together, these results explain protective mechanisms of rare, broad, and potent antibodies and identify a strategy for the rational design of therapeutic modalities against LF and related infectious diseases.
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Affiliation(s)
- Haoyang Li
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, 9420 Athena Circle La Jolla, CA 92037 USA
| | - Tierra Buck
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, 9420 Athena Circle La Jolla, CA 92037 USA
| | - Michelle Zandonatti
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, 9420 Athena Circle La Jolla, CA 92037 USA
| | - Jieyun Yin
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, 9420 Athena Circle La Jolla, CA 92037 USA
| | - Alex Moon-Walker
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, 9420 Athena Circle La Jolla, CA 92037 USA
| | - Jingru Fang
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, 9420 Athena Circle La Jolla, CA 92037 USA
| | - Anatoliy Koval
- Zalgen Labs LLC, 7495 New Horizon Way, Suite 120, Frederick, MD 21703 USA
| | - Megan L. Heinrich
- Zalgen Labs LLC, 7495 New Horizon Way, Suite 120, Frederick, MD 21703 USA
| | - Megan M. Rowland
- Zalgen Labs LLC, 7495 New Horizon Way, Suite 120, Frederick, MD 21703 USA
| | - Ruben Diaz Avalos
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, 9420 Athena Circle La Jolla, CA 92037 USA
| | - Sharon L. Schendel
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, 9420 Athena Circle La Jolla, CA 92037 USA
| | - Diptiben Parekh
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, 9420 Athena Circle La Jolla, CA 92037 USA
| | - Dawid Zyla
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, 9420 Athena Circle La Jolla, CA 92037 USA
| | - Adrian Enriquez
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, 9420 Athena Circle La Jolla, CA 92037 USA
| | - Stephanie Harkins
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, 9420 Athena Circle La Jolla, CA 92037 USA
| | - Brian Sullivan
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, 9420 Athena Circle La Jolla, CA 92037 USA
| | - Victoria Smith
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, 9420 Athena Circle La Jolla, CA 92037 USA
- Department of Medicine, University of California San Diego, La Jolla, CA 92037 USA
| | - Onyeka Chukwudozie
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, 9420 Athena Circle La Jolla, CA 92037 USA
- Department of Medicine, University of California San Diego, La Jolla, CA 92037 USA
| | - Reika Watanabe
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, 9420 Athena Circle La Jolla, CA 92037 USA
| | - James E. Robinson
- Department of Microbiology and Immunology, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA 70118 USA
| | - Robert F. Garry
- Zalgen Labs LLC, 7495 New Horizon Way, Suite 120, Frederick, MD 21703 USA
- Department of Microbiology and Immunology, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA 70118 USA
| | - Luis M. Branco
- Zalgen Labs LLC, 7495 New Horizon Way, Suite 120, Frederick, MD 21703 USA
| | - Kathryn M. Hastie
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, 9420 Athena Circle La Jolla, CA 92037 USA
| | - Erica Ollmann Saphire
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, 9420 Athena Circle La Jolla, CA 92037 USA
- Department of Medicine, University of California San Diego, La Jolla, CA 92037 USA
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8
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Murphy H, Ly H. Understanding Immune Responses to Lassa Virus Infection and to Its Candidate Vaccines. Vaccines (Basel) 2022; 10:1668. [PMID: 36298533 PMCID: PMC9612042 DOI: 10.3390/vaccines10101668] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 09/27/2022] [Accepted: 09/28/2022] [Indexed: 11/29/2022] Open
Abstract
Lassa fever (LF) is a deadly viral hemorrhagic fever disease that is endemic in several countries in West Africa. It is caused by Lassa virus (LASV), which has been estimated to be responsible for approximately 300,000 infections and 5000 deaths annually. LASV is a highly pathogenic human pathogen without effective therapeutics or FDA-approved vaccines. Here, we aim to provide a literature review of the current understanding of the basic mechanism of immune responses to LASV infection in animal models and patients, as well as to several of its candidate vaccines.
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Affiliation(s)
| | - Hinh Ly
- Comparative & Molecular Biosciences Graduate Program, Department of Veterinary & Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, Twin Cities, St Paul, MN 55108, USA
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9
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Fischer K, Topallar S, Kraatz F, Groschup MH, Diederich S. The role of N-linked glycosylation in proteolytic processing and cell surface transport of the Cedar virus fusion protein. Virol J 2022; 19:136. [PMID: 35999637 PMCID: PMC9400332 DOI: 10.1186/s12985-022-01864-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 08/10/2022] [Indexed: 11/10/2022] Open
Abstract
Background N-linked glycans on viral glycoproteins have been shown to be important for protein expression, processing and intracellular transport. The fusion glycoprotein F of Cedar virus (CedV) contains six potential N-glycosylation sites. Findings To investigate their impact on cell surface transport, proteolytic cleavage and biological activity, we disrupted the consensus sequences by conservative mutations (Asn to Gln) and found that five of the six potential N-glycosylation sites are actually utilized. The individual removal of N-glycan g1 (N66), g2 (N79) and g3 (N98) in the CedV F2 subunit had no or only little effect on cell surface transport, proteolytic cleavage and fusion activity of CedV F. Interestingly, removal of N-linked glycan g6 (N463) in the F1 subunit resulted in reduced cell surface expression but slightly increased fusogenicity upon co-expression with the CedV receptor-binding protein G. Most prominent effects however were observed for the disruption of N-glycosylation motif g4 (N413), which significantly impaired the transport of CedV F to the cell surface, thereby also affecting proteolytic cleavage and fusion activity. Conclusions Our findings indicate that the individual N-linked modifications, with the exception of glycan g4, are dispensable for processing of CedV F protein in transfection experiments. However, removal of g4 led to a phenotype that was strongly impaired concerning cell surface expression and proteolytic activation.
Supplementary Information The online version contains supplementary material available at 10.1186/s12985-022-01864-5.
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Affiliation(s)
- Kerstin Fischer
- Institute of Novel and Emerging Infectious Diseases, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Selin Topallar
- Institute of Novel and Emerging Infectious Diseases, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Franziska Kraatz
- Institute of Novel and Emerging Infectious Diseases, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Martin H Groschup
- Institute of Novel and Emerging Infectious Diseases, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Sandra Diederich
- Institute of Novel and Emerging Infectious Diseases, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald-Insel Riems, Germany.
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10
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Enriquez AS, Buck TK, Li H, Norris MJ, Moon-Walker A, Zandonatti MA, Harkins SS, Robinson JE, Branco LM, Garry RF, Saphire EO, Hastie KM. Delineating the mechanism of anti-Lassa virus GPC-A neutralizing antibodies. Cell Rep 2022; 39:110841. [PMID: 35613585 PMCID: PMC9258627 DOI: 10.1016/j.celrep.2022.110841] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 03/16/2022] [Accepted: 04/28/2022] [Indexed: 12/16/2022] Open
Abstract
Lassa virus (LASV) is the etiologic agent of Lassa Fever, a hemorrhagic disease that is endemic to West Africa. During LASV infection, LASV glycoprotein (GP) engages with multiple host receptors for cell entry. Neutralizing antibodies against GP are rare and principally target quaternary epitopes displayed only on the metastable, pre-fusion conformation of GP. Currently, the structural features of the neutralizing GPC-A antibody competition group are understudied. Structures of two GPC-A antibodies presented here demonstrate that they bind the side of the pre-fusion GP trimer, bridging the GP1 and GP2 subunits. Complementary biochemical analyses indicate that antibody 25.10C, which is broadly specific, neutralizes by inhibiting binding of the endosomal receptor LAMP1 and also by blocking membrane fusion. The other GPC-A antibody, 36.1F, which is lineage-specific, prevents LAMP1 association only. These data illuminate a site of vulnerability on LASV GP and will guide efforts to elicit broadly reactive therapeutics and vaccines. Enriquez et al. present two structures of GPC-A antibody Fab fragments bound to Lassa virus glycoprotein. Complementary biochemical analyses illuminate mechanistic differences between pan-Lassa 25.10C and lineage-specific 36.1F. 25.10C inhibits two steps of Lassa virus infection, LAMP1 binding and membrane fusion, while 36.1F only blocks LAMP1.
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Affiliation(s)
| | - Tierra K Buck
- La Jolla Institute for Immunology, La Jolla, CA 92037, USA
| | - Haoyang Li
- La Jolla Institute for Immunology, La Jolla, CA 92037, USA
| | | | - Alex Moon-Walker
- La Jolla Institute for Immunology, La Jolla, CA 92037, USA; Program in Virology, Harvard University, Boston, MA 02115, USA; Department of Molecular Microbiology, Washington University in Saint Louis, St. Louis, MO 63130, USA
| | | | | | - James E Robinson
- Department of Pediatrics, Tulane University School of Medicine, New Orleans, LA 70112, USA
| | | | - Robert F Garry
- Zalgen Labs, LLC, Germantown, MD 20876, USA; Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, LA 70112, USA
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11
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Lassa virus glycoprotein complex review: insights into its unique fusion machinery. Biosci Rep 2022; 42:230708. [PMID: 35088070 PMCID: PMC8844875 DOI: 10.1042/bsr20211930] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 01/24/2022] [Accepted: 01/26/2022] [Indexed: 11/17/2022] Open
Abstract
Lassa virus (LASV), an arenavirus endemic to West Africa, causes Lassa fever—a lethal hemorrhagic fever. Entry of LASV into the host cell is mediated by the glycoprotein complex (GPC), which is the only protein located on the viral surface and comprises three subunits: glycoprotein 1 (GP1), glycoprotein 2 (GP2), and a stable signal peptide (SSP). The LASV GPC is a class one viral fusion protein, akin to those found in viruses such as human immunodeficiency virus (HIV), influenza, Ebola virus (EBOV), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). These viruses are enveloped and utilize membrane fusion to deliver their genetic material to the host cell. Like other class one fusion proteins, LASV-mediated membrane fusion occurs through an orchestrated sequence of conformational changes in its GPC. The receptor-binding subunit, GP1, first engages with a host cell receptor then undergoes a unique receptor switch upon delivery to the late endosome. The acidic pH and change in receptor result in the dissociation of GP1, exposing the fusion subunit, GP2, such that fusion can occur. These events ultimately lead to the formation of a fusion pore so that the LASV genetic material is released into the host cell. Interestingly, the mature GPC retains its SSP as a third subunit—a feature that is unique to arenaviruses. Additionally, the fusion domain contains two separate fusion peptides, instead of a standard singular fusion peptide. Here, we give a comprehensive review of the LASV GPC components and their unusual features.
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12
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Khan T, Khan A, Wei DQ. MMV-db: vaccinomics and RNA-based therapeutics database for infectious hemorrhagic fever-causing mammarenaviruses. Database (Oxford) 2021; 2021:baab063. [PMID: 34679165 PMCID: PMC8533362 DOI: 10.1093/database/baab063] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 08/24/2021] [Accepted: 10/18/2021] [Indexed: 12/24/2022]
Abstract
The recent viral outbreaks and the current pandemic situation urges us to timely address any emerging viral infections by designing therapeutic strategies. Multi-omics and therapeutic data are of great interest to develop early remedial interventions. This work provides a therapeutic data platform (Mammarenavirus (MMV)-db) for pathogenic mammarenaviruses with potential catastrophic effects on human health around the world. The database integrates vaccinomics and RNA-based therapeutics data for seven human pathogenic MMVs associated with severe viral hemorrhagic fever and lethality in humans. Protein-specific cytotoxic T lymphocytes, B lymphocytes, helper T-cell and interferon-inducing epitopes were mapped using a cluster of immune-omics-based algorithms and tools for the seven human pathogenic viral species. Furthermore, the physiochemical and antigenic properties were also explored to guide protein-specific multi-epitope subunit vaccine for each species. Moreover, highly efficacious RNAs (small Interfering RNA (siRNA), microRNA and single guide RNA (sgRNA)) after extensive genome-based analysis with therapeutic relevance were explored. All the therapeutic RNAs were further classified and listed on the basis of predicted higher efficacy. The online platform (http://www.mmvdb.dqweilab-sjtu.com/index.php) contains easily accessible data sets and vaccine designs with potential utility in further computational and experimental work. Conclusively, the current study provides a baseline data platform to secure better future therapeutic interventions against the hemorrhagic fever causing mammarenaviruses. Database URL: http://www.mmvdb.dqweilab-sjtu.com/index.php.
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Affiliation(s)
- Taimoor Khan
- Department of Bioinformatics and Biological Statistics, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang District, Shanghai 200240, P.R. China
| | - Abbas Khan
- Department of Bioinformatics and Biological Statistics, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang District, Shanghai 200240, P.R. China
| | - Dong-Qing Wei
- Department of Bioinformatics and Biological Statistics, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang District, Shanghai 200240, P.R. China
- State Key Laboratory of Microbial Metabolism, Shanghai-Islamabad-Belgrade Joint Innovation Center on Antibacterial Resistances, Joint Laboratory of International Cooperation in Metabolic and Developmental Sciences, Ministry of Education and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200030, P.R. China
- Peng Cheng Laboratory, Vanke Cloud City Phase I Building 8, Xili Street, Nashan District, Shenzhen, Guangdong 518055, P.R China
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13
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Kim YJ, Venturini V, de la Torre JC. Progress in Anti-Mammarenavirus Drug Development. Viruses 2021; 13:v13071187. [PMID: 34206216 PMCID: PMC8310104 DOI: 10.3390/v13071187] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 06/12/2021] [Accepted: 06/19/2021] [Indexed: 12/24/2022] Open
Abstract
Mammarenaviruses are prevalent pathogens distributed worldwide, and several strains cause severe cases of human infections with high morbidity and significant mortality. Currently, there is no FDA-approved antiviral drugs and vaccines against mammarenavirus and the potential treatment option is limited to an off-label use of ribavirin that shows only partial protective effect and associates with side effects. For the past few decades, extensive research has reported potential anti-mammarenaviral drugs and their mechanisms of action in host as well as vaccine candidates. This review describes current knowledge about mammarenavirus virology, progress of antiviral drug development, and technical strategies of drug screening.
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Affiliation(s)
- Yu-Jin Kim
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA; (Y.-J.K.); (V.V.)
| | - Victor Venturini
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA; (Y.-J.K.); (V.V.)
- Department of Biotechnology, Faculty of Experimental Sciences, Francisco de Vitoria University (UFV), Carretera Pozuelo-Majadahonda, Km 1,800, Pozuelo de Alarcón, 28223 Madrid, Spain
| | - Juan C. de la Torre
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA; (Y.-J.K.); (V.V.)
- Correspondence:
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14
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Rossi G, Galosi L, Gavazza A, Cerquetella M, Mangiaterra S. Therapeutic approaches to coronavirus infection according to "One Health" concept. Res Vet Sci 2021; 136:81-88. [PMID: 33588098 PMCID: PMC7871813 DOI: 10.1016/j.rvsc.2021.02.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 02/03/2021] [Accepted: 02/06/2021] [Indexed: 12/16/2022]
Abstract
Coronaviridae constantly infect human and animals causing respiratory, gastroenteric or systemic diseases. Over time, these viruses have shown a marked ability to mutate, jumping over the human-animal barrier, thus becoming from enzootic to zoonotic. In the last years, numerous therapeutic protocols have been developed, mainly for severe acute respiratory syndromes in humans. The aim of this review is to summarize drugs or other approaches used in coronavirus infections focusing on different roles of these molecules or bacterial products on viral adhesion and replication or in modulating the host's immune system. Within the "One Health" concept, the study of viral pathogenic role and possible therapeutic approaches in both humans and animals is essential to protect public health.
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Affiliation(s)
- Giacomo Rossi
- Corresponding author at: School of Biosciences and Veterinary Medicine, University of Camerino, Via Circonvallazione 93/95 – 62024, Matelica (MC), Italy
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15
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Zhu X, Liu Y, Guo J, Cao J, Wang Z, Xiao G, Wang W. Effects of N-Linked Glycan on Lassa Virus Envelope Glycoprotein Cleavage, Infectivity, and Immune Response. Virol Sin 2021; 36:774-783. [PMID: 33689141 PMCID: PMC7945000 DOI: 10.1007/s12250-021-00358-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 01/13/2021] [Indexed: 11/29/2022] Open
Abstract
Lassa virus (LASV) belongs to the Mammarenavirus genus (family Arenaviridae) and causes severe hemorrhagic fever in humans. The glycoprotein complex (GPC) contains eleven N-linked glycans that play essential roles in GPC functionalities such as cleavage, transport, receptor recognition, epitope shielding, and immune response. We used three mutagenesis strategies (asparagine to glutamine, asparagine to alanine, and serine/tyrosine to alanine mutants) to abolish individual glycan chain on GPC and found that all the three strategies led to cleavage inefficiency on the 2nd (N89), 5th (N119), or 8th (N365) glycosylation motif. To evaluate N to Q mutagenesis for further research, it was found that deletion of the 2nd (N89Q) or 8th (N365Q) glycan completely inhibited the transduction efficiency of pseudotyped particles. We further investigated the role of individual glycan on GPC-mediated immune response by DNA immunization of mice. Deletion of the individual 1st (N79Q), 3rd (N99Q), 5th (N119Q), or 6th (N167Q) glycan significantly enhanced the proportion of effector CD4+ cells, whereas deletion of the 1st (N79Q), 2nd (N89Q), 3rd (N99Q), 4th (N109Q), 5th (N119Q), 6th (N167Q), or 9th (N373Q) glycan enhanced the proportion of CD8+ effector T cells. Deletion of specific glycan improves the Th1-type immune response, and abolishment of glycan on GPC generally increases the antibody titer to the glycan-deficient GPC. However, the antibodies from either the mutant or WT GPC-immunized mice show little neutralization effect on wild-type LASV. The glycan residues on GPC provide an immune shield for the virus, and thus represent a target for the design and development of a vaccine.
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Affiliation(s)
- Xueqin Zhu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China.,University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Yang Liu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Jiao Guo
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China.,University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Junyuan Cao
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China.,University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Zonglin Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China.,University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Gengfu Xiao
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China.,University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Wei Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China. .,University of the Chinese Academy of Sciences, Beijing, 100049, China.
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16
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Koma T, Huang C, Coscia A, Hallam S, Manning JT, Maruyama J, Walker AG, Miller M, Smith JN, Patterson M, Abraham J, Paessler S. Glycoprotein N-linked glycans play a critical role in arenavirus pathogenicity. PLoS Pathog 2021; 17:e1009356. [PMID: 33647064 PMCID: PMC7951981 DOI: 10.1371/journal.ppat.1009356] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 03/11/2021] [Accepted: 02/03/2021] [Indexed: 12/15/2022] Open
Abstract
Several arenaviruses cause hemorrhagic fevers in humans with high case fatality rates. A vaccine named Candid#1 is available only against Junin virus (JUNV) in Argentina. Specific N-linked glycans on the arenavirus surface glycoprotein (GP) mask important epitopes and help the virus evade antibody responses. However the role of GPC glycans in arenavirus pathogenicity is largely unclear. In a lethal animal model of hemorrhagic fever-causing Machupo virus (MACV) infection, we found that a chimeric MACV with the ectodomain of GPC from Candid#1 vaccine was partially attenuated. Interestingly, mutations resulting in acquisition of N-linked glycans at GPC N83 and N166 frequently occurred in late stages of the infection. These glycosylation sites are conserved in the GPC of wild-type MACV, indicating that this is a phenotypic reversion for the chimeric MACV to gain those glycans crucial for infection in vivo. Further studies indicated that the GPC mutant viruses with additional glycans became more resistant to neutralizing antibodies and more virulent in animals. On the other hand, disruption of these glycosylation sites on wild-type MACV GPC rendered the virus substantially attenuated in vivo and also more susceptible to antibody neutralization, while loss of these glycans did not affect virus growth in cultured cells. We also found that MACV lacking specific GPC glycans elicited higher levels of neutralizing antibodies against wild-type MACV. Our findings revealed the critical role of specific glycans on GPC in arenavirus pathogenicity and have important implications for rational design of vaccines against this group of hemorrhagic fever-causing viruses. Several arenaviruses cause severe hemorrhagic fevers in humans. The only vaccine against arenavirus infections is Candid#1, a live attenuated vaccine against Argentine hemorrhagic fever. So far, we have successfully attenuated additional one of the arenaviruses, Machupo virus, the causative agent of Bolivian hemorrhagic fever. Unraveling this attenuation mechanism might help the development of live-attenuated vaccines for other arenaviruses. In this study, we revealed that the specific glycans of the viral glycoproteins play an important role in pathogenicity in vivo. The glycans facilitate the virus to evade neutralizing antibodies. This study would contribute to the development of arenavirus vaccine candidates.
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Affiliation(s)
- Takaaki Koma
- Department of Pathology, University of Texas Medical Branch at Galveston, Texas, United States of America
| | - Cheng Huang
- Department of Pathology, University of Texas Medical Branch at Galveston, Texas, United States of America
| | - Adrian Coscia
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Steven Hallam
- Department of Pathology, University of Texas Medical Branch at Galveston, Texas, United States of America
| | - John T. Manning
- Department of Pathology, University of Texas Medical Branch at Galveston, Texas, United States of America
| | - Junki Maruyama
- Department of Pathology, University of Texas Medical Branch at Galveston, Texas, United States of America
| | - Aida G. Walker
- Department of Pathology, University of Texas Medical Branch at Galveston, Texas, United States of America
| | - Milagros Miller
- Department of Pathology, University of Texas Medical Branch at Galveston, Texas, United States of America
| | - Jeanon N. Smith
- Department of Pathology, University of Texas Medical Branch at Galveston, Texas, United States of America
| | - Michael Patterson
- Department of Pathology, University of Texas Medical Branch at Galveston, Texas, United States of America
| | - Jonathan Abraham
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Slobodan Paessler
- Department of Pathology, University of Texas Medical Branch at Galveston, Texas, United States of America
- * E-mail:
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17
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Cao J, Zhang G, Zhou M, Liu Y, Xiao G, Wang W. Characterizing the Lassa Virus Envelope Glycoprotein Membrane Proximal External Region for Its Role in Fusogenicity. Virol Sin 2020; 36:273-280. [PMID: 32897505 DOI: 10.1007/s12250-020-00286-3] [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: 04/30/2020] [Accepted: 07/22/2020] [Indexed: 10/23/2022] Open
Abstract
The membrane-proximal external region (MPER) of Lassa virus (LASV) glycoprotein complex (GPC) is critical in modulating its functionality. Till now, the high-resolution structure of the intact GPC, including MPER is not available. In this study, we used alanine substitution to scan all 16 residues located in LASV MPER. Western blotting and quantification fusion assay showed that the residues located at the C terminus of the HR2 (M414 and L415) and N terminus of the MPER (K417 and Y419) are critical for GPC-mediated membrane fusion function. Furthermore, cell surface biotinylation experiments revealed that M414A, K417A and Y419A expressed similar levels as WT, whereas L415A mutant led to a reduction of mature GPC on the cell surface. Moreover, substitution of these residues with the similar residue such as M414L, L415I, K417R and Y419F would partly compensate the loss of the fusion activity caused by the alanine mutant in these sites. Results from this study showed that several key residues in the MPER region are indispensable to promote the conformational changes that drive fusion events and shed light on the structure analysis of LASV GPC and anti-LASV therapeutics.
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Affiliation(s)
- Junyuan Cao
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China.,University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Guangshun Zhang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China.,College of Life Sciences, Nankai University, Tianjin, 300353, China
| | - Minmin Zhou
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China.,University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Yang Liu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China.,University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Gengfu Xiao
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China. .,University of the Chinese Academy of Sciences, Beijing, 100049, China.
| | - Wei Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China. .,University of the Chinese Academy of Sciences, Beijing, 100049, China.
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18
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Müller H, Fehling SK, Dorna J, Urbanowicz RA, Oestereich L, Krebs Y, Kolesnikova L, Schauflinger M, Krähling V, Magassouba N, Fichet-Calvet E, Ball JK, Kaufmann A, Bauer S, Becker S, von Messling V, Strecker T. Adjuvant formulated virus-like particles expressing native-like forms of the Lassa virus envelope surface glycoprotein are immunogenic and induce antibodies with broadly neutralizing activity. NPJ Vaccines 2020; 5:71. [PMID: 32802410 PMCID: PMC7403343 DOI: 10.1038/s41541-020-00219-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 07/10/2020] [Indexed: 01/11/2023] Open
Abstract
Lassa mammarenavirus (LASV) is a rodent-borne arenavirus endemic to several West African countries. It is the causative agent of human Lassa fever, an acute viral hemorrhagic fever disease. To date, no therapeutics or vaccines against LASV have obtained regulatory approval. Polyclonal neutralizing antibodies derived from hyperimmunized animals may offer a useful strategy for prophylactic and therapeutic intervention to combat human LASV infections. The LASV envelope surface glycoprotein complex (GP) is the major target for neutralizing antibodies, and it is the main viral antigen used for the design of an LASV vaccine. Here, we assessed the immunogenic potential of mammalian cell-derived virus-like particles (VLPs) expressing GP from the prototypic LASV strain Josiah in a native-like conformation as the sole viral antigen. We demonstrate that an adjuvanted prime-boost immunization regimen with GP-derived VLPs elicited neutralizing antibody responses in rabbits, suggesting that effective antigenic epitopes of GP were displayed. Notably, these antibodies exhibited broad reactivity across five genetic lineages of LASV. VLP-based immunization strategies may represent a powerful approach for generating polyclonal sera containing cross-reactive neutralizing antibodies against LASV.
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Affiliation(s)
- Helena Müller
- Institute of Virology, Philipps University Marburg, Marburg, Germany
| | | | - Jens Dorna
- Institute of Immunology, Philipps University Marburg, Marburg, Germany
| | - Richard A Urbanowicz
- Wolfson Centre for Global Virus Infections, University of Nottingham, Nottingham, UK.,School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Lisa Oestereich
- Bernhard-Nocht Institute for Tropical Medicine, Hamburg, Germany.,German Center for Infection Research (DZIF), Partner Sites Gießen-Marburg-Langen and Hamburg-Borstel-Lübeck-Riems, Hamburg, Germany
| | - Yvonne Krebs
- Veterinary Medicine Division, Paul-Ehrlich-Institut, Langen, Germany
| | | | | | - Verena Krähling
- Institute of Virology, Philipps University Marburg, Marburg, Germany.,German Center for Infection Research (DZIF), Partner Sites Gießen-Marburg-Langen and Hamburg-Borstel-Lübeck-Riems, Hamburg, Germany
| | | | - Elisabeth Fichet-Calvet
- Bernhard-Nocht Institute for Tropical Medicine, Hamburg, Germany.,German Center for Infection Research (DZIF), Partner Sites Gießen-Marburg-Langen and Hamburg-Borstel-Lübeck-Riems, Hamburg, Germany
| | - Jonathan K Ball
- Wolfson Centre for Global Virus Infections, University of Nottingham, Nottingham, UK.,School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Andreas Kaufmann
- Institute of Immunology, Philipps University Marburg, Marburg, Germany
| | - Stefan Bauer
- Institute of Immunology, Philipps University Marburg, Marburg, Germany
| | - Stephan Becker
- Institute of Virology, Philipps University Marburg, Marburg, Germany.,German Center for Infection Research (DZIF), Partner Sites Gießen-Marburg-Langen and Hamburg-Borstel-Lübeck-Riems, Hamburg, Germany
| | - Veronika von Messling
- German Center for Infection Research (DZIF), Partner Sites Gießen-Marburg-Langen and Hamburg-Borstel-Lübeck-Riems, Hamburg, Germany.,Veterinary Medicine Division, Paul-Ehrlich-Institut, Langen, Germany.,Present Address: Federal Ministry for Education and Research, Berlin, Germany
| | - Thomas Strecker
- Institute of Virology, Philipps University Marburg, Marburg, Germany
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19
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Hariharan V, Kane RS. Glycosylation as a tool for rational vaccine design. Biotechnol Bioeng 2020; 117:2556-2570. [PMID: 32330286 DOI: 10.1002/bit.27361] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 04/01/2020] [Accepted: 04/22/2020] [Indexed: 12/31/2022]
Abstract
The discovery of broadly neutralizing antibodies that can neutralize multiple strains or subtypes of a pathogen has renewed interest in the development of broadly protective vaccines. To that end, there has been an interest in designing immunofocusing strategies to direct the immune response to specific, conserved regions on antigenic proteins. Modulation of glycosylation is one such immunofocusing strategy; extensive glycosylation is often exploited by pathogens for immune evasion. Masking epitopes on protein immunogens with "self" glycans can also shield the underlying protein surface from humoral immune surveillance. We review recent advances in applying glycosylation as an immunofocusing tool. We also highlight recent interesting work in the HIV-1 field involving the identification and elicitation of broadly neutralizing antibodies that incorporate glycans into their binding epitopes.
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Affiliation(s)
- Vivek Hariharan
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia
| | - Ravi S Kane
- School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia
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20
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Hastie KM, Cross RW, Harkins SS, Zandonatti MA, Koval AP, Heinrich ML, Rowland MM, Robinson JE, Geisbert TW, Garry RF, Branco LM, Saphire EO. Convergent Structures Illuminate Features for Germline Antibody Binding and Pan-Lassa Virus Neutralization. Cell 2020; 178:1004-1015.e14. [PMID: 31398326 DOI: 10.1016/j.cell.2019.07.020] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 05/01/2019] [Accepted: 07/12/2019] [Indexed: 01/12/2023]
Abstract
Lassa virus (LASV) causes hemorrhagic fever and is endemic in West Africa. Protective antibody responses primarily target the LASV surface glycoprotein (GPC), and GPC-B competition group antibodies often show potent neutralizing activity in humans. However, which features confer potent and broadly neutralizing antibody responses is unclear. Here, we compared three crystal structures of LASV GPC complexed with GPC-B antibodies of varying neutralization potency. Each GPC-B antibody recognized an overlapping epitope involved in binding of two adjacent GPC monomers and preserved the prefusion trimeric conformation. Differences among GPC-antibody interactions highlighted specific residues that enhance neutralization. Using structure-guided amino acid substitutions, we increased the neutralization potency and breadth of these antibodies to include all major LASV lineages. The ability to define antibody residues that allow potent and broad neutralizing activity, together with findings from analyses of inferred germline precursors, is critical to develop potent therapeutics and for vaccine design and assessment.
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Affiliation(s)
- Kathryn M Hastie
- La Jolla Institute for Immunology, La Jolla, CA, USA; Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, USA
| | - Robert W Cross
- University of Texas Medical Branch, Galveston National Laboratory, Galveston, TX, USA
| | - Stephanie S Harkins
- La Jolla Institute for Immunology, La Jolla, CA, USA; Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, USA
| | - Michelle A Zandonatti
- La Jolla Institute for Immunology, La Jolla, CA, USA; Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, USA
| | | | | | | | - James E Robinson
- Department of Pediatrics, School of Medicine, Tulane University, New Orleans, LA, USA
| | - Thomas W Geisbert
- University of Texas Medical Branch, Galveston National Laboratory, Galveston, TX, USA
| | - Robert F Garry
- Zalgen Labs, Germantown, MD, USA; Department of Microbiology and Immunology, Tulane University, New Orleans, LA, USA
| | | | - Erica Ollmann Saphire
- La Jolla Institute for Immunology, La Jolla, CA, USA; Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, USA; Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA, USA.
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21
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Ibukun FI. Inter-Lineage Variation of Lassa Virus Glycoprotein Epitopes: A Challenge to Lassa Virus Vaccine Development. Viruses 2020; 12:v12040386. [PMID: 32244402 PMCID: PMC7232328 DOI: 10.3390/v12040386] [Citation(s) in RCA: 20] [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: 02/22/2020] [Revised: 03/26/2020] [Accepted: 03/30/2020] [Indexed: 12/12/2022] Open
Abstract
Lassa virus (LASV), which causes considerable morbidity and mortality annually, has a high genetic diversity across West Africa. LASV glycoprotein (GP) expresses this diversity, but most LASV vaccine candidates utilize only the Lineage IV LASV Josiah strain GP antigen as an immunogen and homologous challenge with Lineage IV LASV. In addition to the sequence variation amongst the LASV lineages, these lineages are also distinguished in their presentations. Inter-lineage variations within previously mapped B-cell and T-cell LASV GP epitopes and the breadth of protection in LASV vaccine/challenge studies were examined critically. Multiple alignments of the GP primary sequence of strains from each LASV lineage showed that LASV GP has diverging degrees of amino acid conservation within known epitopes among LASV lineages. Conformational B-cell epitopes spanning different sites in GP subunits were less impacted by LASV diversity. LASV GP diversity should influence the approach used for LASV vaccine design. Expression of LASV GP on viral vectors, especially in its prefusion configuration, has shown potential for protective LASV vaccines that can overcome LASV diversity. Advanced vaccine candidates should demonstrate efficacy against all LASV lineages for evidence of a pan-LASV vaccine.
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Affiliation(s)
- Francis Ifedayo Ibukun
- Institute of Human Virology, University of Maryland School of Medicine, Baltimore, 21201, MD, USA
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22
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Comprehensive Interactome Analysis Reveals that STT3B Is Required for N-Glycosylation of Lassa Virus Glycoprotein. J Virol 2019; 93:JVI.01443-19. [PMID: 31511384 PMCID: PMC6854512 DOI: 10.1128/jvi.01443-19] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 09/03/2019] [Indexed: 12/28/2022] Open
Abstract
Glycoproteins play vital roles in the arenavirus life cycle by facilitating virus entry and participating in the virus budding process. N-glycosylation of GPs is responsible for their proper functioning; however, little is known about the host factors on which the virus depends for this process. In this study, a comprehensive LASV GP interactome was characterized, and further study revealed that STT3B-dependent N-glycosylation was preferentially required by arenavirus GPs and critical for virus infectivity. The two specific thioredoxin subunits of STT3B-OST MAGT1 and TUSC3 were found to be essential for the N-glycosylation of viral GP. NGI-1, a small-molecule inhibitor of OST, also showed a robust inhibitory effect on arenavirus. Our study provides new insights into LASV GP-host interactions and extends the potential targets for the development of novel therapeutics against Lassa fever in the future. Lassa virus (LASV) is the causative agent of a fatal hemorrhagic fever in humans. The glycoprotein (GP) of LASV mediates viral entry into host cells, and correct processing and modification of GP by host factors is a prerequisite for virus replication. Here, using an affinity purification-coupled mass spectrometry (AP-MS) strategy, 591 host proteins were identified as interactors of LASV GP. Gene ontology analysis was performed to functionally annotate these proteins, and the oligosaccharyltransferase (OST) complex was highly enriched. Functional studies conducted by using CRISPR-Cas9-mediated knockouts showed that STT3A and STT3B, the two catalytically active isoforms of the OST complex, are essential for the propagation of the recombinant arenavirus rLCMV/LASV glycoprotein precursor, mainly via affecting virus infectivity. Knockout of STT3B, but not STT3A, caused hypoglycosylation of LASV GP, indicating a preferential requirement of LASV for the STT3B-OST isoform. Furthermore, double knockout of magnesium transporter 1 (MAGT1) and tumor suppressor candidate 3 (TUSC3), two specific subunits of STT3B-OST, also caused hypoglycosylation of LASV GP and affected virus propagation. Site-directed mutagenesis analysis revealed that the oxidoreductase CXXC active-site motif of MAGT1 or TUSC3 is essential for the glycosylation of LASV GP. NGI-1, a small-molecule OST inhibitor, can effectively reduce virus infectivity without affecting cell viability. The STT3B-dependent N-glycosylation of GP is conserved among other arenaviruses, including both the Old World and New World groups. Our study provided a systematic view of LASV GP-host interactions and revealed the preferential requirement of STT3B for LASV GP N-glycosylation. IMPORTANCE Glycoproteins play vital roles in the arenavirus life cycle by facilitating virus entry and participating in the virus budding process. N-glycosylation of GPs is responsible for their proper functioning; however, little is known about the host factors on which the virus depends for this process. In this study, a comprehensive LASV GP interactome was characterized, and further study revealed that STT3B-dependent N-glycosylation was preferentially required by arenavirus GPs and critical for virus infectivity. The two specific thioredoxin subunits of STT3B-OST MAGT1 and TUSC3 were found to be essential for the N-glycosylation of viral GP. NGI-1, a small-molecule inhibitor of OST, also showed a robust inhibitory effect on arenavirus. Our study provides new insights into LASV GP-host interactions and extends the potential targets for the development of novel therapeutics against Lassa fever in the future.
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23
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Cross RW, Hastie KM, Mire CE, Robinson JE, Geisbert TW, Branco LM, Ollmann Saphire E, Garry RF. Antibody therapy for Lassa fever. Curr Opin Virol 2019; 37:97-104. [PMID: 31401518 DOI: 10.1016/j.coviro.2019.07.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Revised: 07/01/2019] [Accepted: 07/03/2019] [Indexed: 02/06/2023]
Abstract
Serum from convalescent Lassa fever patients was previously shown to be ineffective as a source of protective antibodies in some early studies. Subsequently, monoclonal antibodies (MAbs) to the Lassa virus (LASV) glycoprotein produced by memory B cells of West African patients who survived Lassa fever were identified. Development of MAbs as potential Lassa immunotherapeutics was facilitated by structural studies and mutational analyses that identified protective epitopes on the prefusion form of the LASV glycoprotein. Human mAbs were screened for reactivity to different neutralizing epitopes, potency, and broad reactivity against multiple lineages of LASV. MAbs were downselected in a guinea pig model of Lassa fever. A cocktail of three human MAbs designated Arevirumab-3 rescued 100% of Cynomolgus macaques at advanced stages of disease more than a week post-infection. Antibody therapeutics may be further developed in clinical trials in endemic areas potentially offering a key treatment option for Lassa fever.
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Affiliation(s)
- Robert W Cross
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA; Galveston National Laboratory, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA
| | | | - Chad E Mire
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA; Galveston National Laboratory, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA
| | - James E Robinson
- Department of Pediatrics, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA 70112, USA
| | - Thomas W Geisbert
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA; Galveston National Laboratory, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA
| | | | | | - Robert F Garry
- Zalgen Labs, LLC, Germantown, MD 20876, USA; Department of Microbiology and Immunology, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA 70112, USA.
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24
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Brisse ME, Ly H. Hemorrhagic Fever-Causing Arenaviruses: Lethal Pathogens and Potent Immune Suppressors. Front Immunol 2019; 10:372. [PMID: 30918506 PMCID: PMC6424867 DOI: 10.3389/fimmu.2019.00372] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 02/14/2019] [Indexed: 12/22/2022] Open
Abstract
Hemorrhagic fevers (HF) resulting from pathogenic arenaviral infections have traditionally been neglected as tropical diseases primarily affecting African and South American regions. There are currently no FDA-approved vaccines for arenaviruses, and treatments have been limited to supportive therapy and use of non-specific nucleoside analogs, such as Ribavirin. Outbreaks of arenaviral infections have been limited to certain geographic areas that are endemic but known cases of exportation of arenaviruses from endemic regions and socioeconomic challenges for local control of rodent reservoirs raise serious concerns about the potential for larger outbreaks in the future. This review synthesizes current knowledge about arenaviral evolution, ecology, transmission patterns, life cycle, modulation of host immunity, disease pathogenesis, as well as discusses recent development of preventative and therapeutic pursuits against this group of deadly viral pathogens.
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Affiliation(s)
- Morgan E Brisse
- Biochemistry, Molecular Biology, and Biophysics Graduate Program, University of Minnesota, St. Paul, MN, United States.,Department of Veterinary and Biomedical Sciences, University of Minnesota, St. Paul, MN, United States
| | - Hinh Ly
- Department of Veterinary and Biomedical Sciences, University of Minnesota, St. Paul, MN, United States
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25
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Stewart AN, Tan SY, Clark DJ, Zhang H, Wong GW. N-Linked Glycosylation-Dependent and -Independent Mechanisms Regulating CTRP12 Cleavage, Secretion, and Stability. Biochemistry 2019; 58:727-741. [PMID: 30566828 DOI: 10.1021/acs.biochem.8b00528] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
C1q/TNF-related protein 12 (CTRP12) is a secreted regulator of glucose and lipid metabolism. It circulates in plasma as a full-length protein or as a cleaved isoform generated by furin/PCSK3 cleavage. These isoforms preferentially activate different signaling pathways, and their ratio in plasma is altered in obesity and diabetes. Here, we show that three conserved asparagine residues (Asn-39, Asn-287, and Asn-297) play important roles in modulating CTRP12 cleavage, secretion, and stability. Mass spectrometry analysis provided direct evidence of Asn-39 glycosylation. When N-linked glycosylation was inhibited by tunicamycin or abolished by the N39Q, N39A, or T41A mutation, CTRP12 cleavage was enhanced. Complex-type N-glycans on CTRP12 blocked cleavage by the Golgi-localized furin. In N-acetylglucosaminyltransferase I (GnTI)-deficient cells that could not form hybrid and complex-type N-glycans in the Golgi, CTRP12 cleavage was enhanced, and re-expressing GnTI reduced cleavage. Replacing the nonglycosylated Asn-297 with glutamine or alanine also increased CTRP12 cleavage. Both Asn-39 and Asn-297 contributed independently to CTRP12 cleavage: maximum cleavage was observed in the double mutant. In addition, CTRP12 cleavage was abolished in furin-deficient cells and restored by furin re-expression. Replacing the nonglycosylated Asn-287 with glutamine or alanine resulted in protein misfolding and aggregation, leading to retention in the endoplasmic reticulum. Cycloheximide chase analyses indicated reduced protein stability for N39Q, T41A, and N297Q mutants. Lastly, we show that increasing the flux through the hexosamine biosynthesis pathway by exogenous glucosamine, known to disrupt protein glycosylation, also promoted CTRP12 cleavage. Combined, these data highlight glycosylation-dependent and -independent mechanisms regulating CTRP12 cleavage, secretion, and protein stability.
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Affiliation(s)
- Ashley N Stewart
- Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Stefanie Y Tan
- Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - David J Clark
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Hui Zhang
- Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - G William Wong
- Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
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26
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Selim KM, Selim A, Arafa A, Hussein HA, Elsanousi AA. Molecular characterization of full fusion protein (F) of Newcastle disease virus genotype VIId isolated from Egypt during 2012-2016. Vet World 2018; 11:930-938. [PMID: 30147262 PMCID: PMC6097568 DOI: 10.14202/vetworld.2018.930-938] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 05/29/2018] [Indexed: 01/03/2023] Open
Abstract
Aim: The aim of this work was to study the full F gene sequence of Newcastle disease virus (NDV) in regard to pathotyping and genotyping and to study the evolution of this NDV in Egypt. Materials and Methods: The present study was conducted using samples from seven suspected NDV flocks of vaccinated chickens during 2012-2016 from six governorates in Egypt. The NDV was successfully isolated from pathological specimens through inoculation in specific pathogen-free embryonated chicken eggs. Results: Pathogenicity of the NDV isolates has been estimated through intracerebral pathogenicity index and ranged from 1.66 to 1.73 which indicates the velogenic type of NDV isolates. Pathotyping and genotyping of these isolates were done through sequencing of full-length F gene. Results indicated that the seven NDV isolates showed characteristic cleavage site motif (112RRQKRF117) for the velogenic strains of NDV. Phylogenetic analysis of the F gene clustered these isolates within Group I of genotype VIId within Israeli strains NDV/IS/2015, NDV-Ch/SD883, and most of the Middle East strains. Six of seven sequenced isolates have six potential N-linked glycosylation sites. The neutralization epitope on the five antigenic sites of fusion is conserved in all Egyptian strains of this study except NDV-KFR-B7-2012 which has a substitution at D 170 N in epitope A4. In all our strains, 10 cysteine residues are recorded, except one loss of cysteine at residue 370 in both NDV-EG-35-2014 and NDV-GHB-328F-2016. Conclusion: All viruses in this study have 52 amino acid substitutions within fusion gene in compared with Lasota strain that reveals importance for its antigenic and structural function. The present work highlights the important need to sequence F gene of NDV genotype VIId to investigate the evolution of this NDV in Egypt.
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Affiliation(s)
- Karim M Selim
- National Laboratory for Veterinary Quality Control on Poultry Production, Animal Health Research Institute, P.O. Box 264-Dokki, Giza 12618, Egypt
| | - Abdullah Selim
- National Laboratory for Veterinary Quality Control on Poultry Production, Animal Health Research Institute, P.O. Box 264-Dokki, Giza 12618, Egypt
| | - Abdelsatar Arafa
- National Laboratory for Veterinary Quality Control on Poultry Production, Animal Health Research Institute, P.O. Box 264-Dokki, Giza 12618, Egypt
| | - Hussein A Hussein
- Department of Virology, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt
| | - Ahmed A Elsanousi
- Department of Virology, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt
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27
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Watanabe Y, Raghwani J, Allen JD, Seabright GE, Li S, Moser F, Huiskonen JT, Strecker T, Bowden TA, Crispin M. Structure of the Lassa virus glycan shield provides a model for immunological resistance. Proc Natl Acad Sci U S A 2018; 115:7320-7325. [PMID: 29941589 PMCID: PMC6048489 DOI: 10.1073/pnas.1803990115] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Lassa virus is an Old World arenavirus endemic to West Africa that causes severe hemorrhagic fever. Vaccine development has focused on the envelope glycoprotein complex (GPC) that extends from the virion envelope. The often inadequate antibody immune response elicited by both vaccine and natural infection has been, in part, attributed to the abundance of N-linked glycosylation on the GPC. Here, using a virus-like-particle system that presents Lassa virus GPC in a native-like context, we determine the composite population of each of the N-linked glycosylation sites presented on the trimeric GPC spike. Our analysis reveals the presence of underprocessed oligomannose-type glycans, which form punctuated clusters that obscure the proteinous surface of both the GP1 attachment and GP2 fusion glycoprotein subunits of the Lassa virus GPC. These oligomannose clusters are seemingly derived as a result of sterically reduced accessibility to glycan processing enzymes, and limited amino acid diversification around these sites supports their role protecting against the humoral immune response. Combined, our data provide a structure-based blueprint for understanding how glycans render the glycoprotein spikes of Lassa virus and other Old World arenaviruses immunologically resistant targets.
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Affiliation(s)
- Yasunori Watanabe
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, OX1 3QU Oxford, United Kingdom
- Division of Structural Biology, University of Oxford, OX3 7BN Oxford, United Kingdom
- Centre for Biological Sciences and Institute of Life Sciences, University of Southampton, SO17 1BJ Southampton, United Kingdom
| | - Jayna Raghwani
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Medicine, University of Oxford, OX3 7LF Oxford, United Kingdom
| | - Joel D Allen
- Centre for Biological Sciences and Institute of Life Sciences, University of Southampton, SO17 1BJ Southampton, United Kingdom
| | - Gemma E Seabright
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, OX1 3QU Oxford, United Kingdom
- Centre for Biological Sciences and Institute of Life Sciences, University of Southampton, SO17 1BJ Southampton, United Kingdom
| | - Sai Li
- Division of Structural Biology, University of Oxford, OX3 7BN Oxford, United Kingdom
| | - Felipe Moser
- Division of Structural Biology, University of Oxford, OX3 7BN Oxford, United Kingdom
| | - Juha T Huiskonen
- Division of Structural Biology, University of Oxford, OX3 7BN Oxford, United Kingdom
- Helsinki Institute of Life Science and Molecular and Integrative Biosciences Research Program, University of Helsinki, 00014 Helsinki, Finland
| | - Thomas Strecker
- Institute of Virology, Philipps Universität Marburg, 35043 Marburg, Germany
| | - Thomas A Bowden
- Division of Structural Biology, University of Oxford, OX3 7BN Oxford, United Kingdom;
| | - Max Crispin
- Centre for Biological Sciences and Institute of Life Sciences, University of Southampton, SO17 1BJ Southampton, United Kingdom;
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28
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Böttcher-Friebertshäuser E, Garten W, Klenk HD. Characterization of Proprotein Convertases and Their Involvement in Virus Propagation. ACTIVATION OF VIRUSES BY HOST PROTEASES 2018. [PMCID: PMC7122180 DOI: 10.1007/978-3-319-75474-1_9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
| | - Wolfgang Garten
- Institut für Virologie, Philipps Universität, Marburg, Germany
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29
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Cysteines and N-Glycosylation Sites Conserved among All Alphaherpesviruses Regulate Membrane Fusion in Herpes Simplex Virus 1 Infection. J Virol 2017; 91:JVI.00873-17. [PMID: 28835497 DOI: 10.1128/jvi.00873-17] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Accepted: 08/14/2017] [Indexed: 01/22/2023] Open
Abstract
Neurotropism is a defining characteristic of alphaherpesvirus pathogenicity. Glycoprotein K (gK) is a conserved virion glycoprotein of all alphaherpesviruses that is not found in other herpesvirus subfamilies. The extracellular amino terminus of gK has been shown to be important to the ability of the prototypic alphaherpesvirus herpes simplex virus 1 (HSV-1) to enter neurons via axonal termini. Here, we determined the role of the two conserved N-linked glycosylation (N48 and N58) sites of gK in virus-induced cell fusion and replication. We found that N-linked glycosylation is important to the regulation of HSV-1-induced membrane fusion since mutating N58 to alanine (N58A) caused extensive virus-induced cell fusion. Due to the known contributions of N-linked glycosylation to protein processing and correct disulfide bond formation, we investigated whether the conserved extracellular cysteine residues within the amino terminus of gK contributed to the regulation of HSV-1-induced membrane fusion. We found that mutation of C37 and C114 residues led to a gK-null phenotype characterized by very small plaque formation and drastic reduction in infectious virus production, while mutation of C82 and C243 caused extensive virus-induced cell fusion. Comparison of N-linked glycosylation and cysteine mutant replication kinetics identified disparate effects on infectious virion egress from infected cells. Specifically, cysteine mutations caused defects in the accumulation of infectious virus in both the cellular and supernatant fractions, while glycosylation site mutants did not adversely affect virion egress from infected cells. These results demonstrate a critical role for the N glycosylation sites and cysteines for the structure and function of the amino terminus of gK.IMPORTANCE We have previously identified important entry and neurotropic determinants in the amino terminus of HSV-1 glycoprotein K (gK). Alphaherpesvirus-mediated membrane fusion is a complex and highly regulated process that is not clearly understood. gK and UL20, which are highly conserved across all alphaherpesviruses, play important roles in the regulation of HSV-1 fusion in the context of infection. A greater understanding of mechanisms governing alphaherpesvirus membrane fusion is expected to inform the rational design of therapeutic and prevention strategies to combat herpesviral infection and pathogenesis. This work adds to the growing reports regarding the importance of gK to alphaherpesvirus pathogenesis and details important structural features of gK that are involved in gK-mediated regulation of virus-induced membrane fusion.
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30
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Acciani M, Alston JT, Zhao G, Reynolds H, Ali AM, Xu B, Brindley MA. Mutational Analysis of Lassa Virus Glycoprotein Highlights Regions Required for Alpha-Dystroglycan Utilization. J Virol 2017; 91:e00574-17. [PMID: 28679759 PMCID: PMC5571257 DOI: 10.1128/jvi.00574-17] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 06/22/2017] [Indexed: 12/27/2022] Open
Abstract
Lassa virus (LASV) is an enveloped RNA virus endemic to West Africa and responsible for severe cases of hemorrhagic fever. Virus entry is mediated by the glycoprotein complex consisting of a stable-signal peptide, a receptor-binding subunit, GP1, and a viral-host membrane fusion subunit, GP2. Several cellular receptors can interact with the GP1 subunit and mediate viral entry, including alpha-dystroglycan (αDG) and lysosome-associated membrane protein 1 (LAMP1). In order to define the regions within GP1 that interact with the cellular receptors, we implemented insertional mutagenesis, carbohydrate shielding, and alanine scanning mutagenesis. Eighty GP constructs were engineered and evaluated for GP1-GP2 processing, surface expression, and the ability to mediate cell-to-cell fusion after low-pH exposure. To examine virus-to-cell entry, 49 constructs were incorporated onto vesicular stomatitis virus (VSV) pseudoparticles and transduction efficiencies were monitored in HAP1 and HAP1-ΔDAG1 cells that differentially produce the αDG cell surface receptor. Seven constructs retained efficient transduction in HAP1-ΔDAG1 cells yet poorly transduced HAP1 cells, suggesting that they are involved in αDG utilization. Residues H141, N146, F147, and Y150 cluster at the predicted central core of the trimeric interface and are important for GP-αDG interaction. Additionally, H92A-H93A, 150HA, 172HA, and 230HA displayed reduced transduction in both HAP1 and HAP1-ΔDAG1 cells, despite efficient cell-to-cell fusion activity. These mutations may interfere with interactions with the endosomal receptor LAMP1 or interfere at another stage in entry that is common to both cell lines. Insight gained from these data can aid in the development of more-effective entry inhibitors by blocking receptor interactions.IMPORTANCE Countries in which Lassa virus is endemic, such as Nigeria, Sierra Leone, Guinea, and Liberia, usually experience a seasonal outbreak of the virus from December to March. Currently, there is neither a preventative vaccine nor a therapeutic available to effectively treat severe Lassa fever. One way to thwart virus infection is to inhibit interaction with cellular receptors. It is known that the GP1 subunit of the Lassa glycoprotein complex plays a critical role in receptor recognition. Our results highlight a region within the Lassa virus GP1 protein that interacts with the cellular receptor alpha-dystroglycan. This information may be used for future development of new Lassa virus antivirals.
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Affiliation(s)
- Marissa Acciani
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA
| | - Jacob T Alston
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA
| | - Guohui Zhao
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA
| | - Hayley Reynolds
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA
| | - Afroze M Ali
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA
| | - Brian Xu
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA
| | - Melinda A Brindley
- Department of Infectious Diseases, Department of Population Health, Center for Vaccines and Immunology, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA
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Hastie KM, Zandonatti MA, Kleinfelter LM, Heinrich ML, Rowland MM, Chandran K, Branco LM, Robinson JE, Garry RF, Saphire EO. Structural basis for antibody-mediated neutralization of Lassa virus. Science 2017; 356:923-928. [PMID: 28572385 PMCID: PMC6007842 DOI: 10.1126/science.aam7260] [Citation(s) in RCA: 153] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 04/28/2017] [Indexed: 12/25/2022]
Abstract
The arenavirus Lassa causes severe hemorrhagic fever and a significant disease burden in West Africa every year. The glycoprotein, GPC, is the sole antigen expressed on the viral surface and the critical target for antibody-mediated neutralization. Here we present the crystal structure of the trimeric, prefusion ectodomain of Lassa GP bound to a neutralizing antibody from a human survivor at 3.2-angstrom resolution. The antibody extensively anchors two monomers together at the base of the trimer, and biochemical analysis suggests that it neutralizes by inhibiting conformational changes required for entry. This work illuminates pH-driven conformational changes in both receptor-binding and fusion subunits of Lassa virus, illustrates the unique assembly of the arenavirus glycoprotein spike, and provides a much-needed template for vaccine design against these threats to global health.
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Affiliation(s)
- Kathryn M Hastie
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Michelle A Zandonatti
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Lara M Kleinfelter
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA
| | | | | | - Kartik Chandran
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA
| | | | - James E Robinson
- Department of Pediatrics, School of Medicine, Tulane University, New Orleans, LA, USA
| | - Robert F Garry
- Zalgen Labs, Germantown, MD, USA
- Department of Microbiology and Immunology, Tulane University, New Orleans, LA, USA
| | - Erica Ollmann Saphire
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037, USA.
- Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA, USA
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Shrivastava-Ranjan P, Bergeron É, Chakrabarti AK, Albariño CG, Flint M, Nichol ST, Spiropoulou CF. 25-Hydroxycholesterol Inhibition of Lassa Virus Infection through Aberrant GP1 Glycosylation. mBio 2016; 7:e01808-16. [PMID: 27999160 PMCID: PMC5181775 DOI: 10.1128/mbio.01808-16] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 11/22/2016] [Indexed: 12/18/2022] Open
Abstract
Lassa virus (LASV) infection is a major public health concern due to high fatality rates and limited effective treatment. The interferon-stimulated gene cholesterol 25-hydroxylase (CH25H) encodes an enzyme that catalyzes the production of 25-hydroxycholesterol (25HC). 25HC is involved in regulating cholesterol biosynthesis and has recently been identified as a potent antiviral targeting enveloped virus entry. Here, we show a previously unrecognized role of CH25H in inhibiting LASV glycoprotein glycosylation and the production of infectious virus. Overexpression of CH25H or treatment with 25HC decreased LASV G1 glycoprotein N-glycan maturation and reduced the production of infectious LASV. Depletion of endogenous CH25H using small interfering RNA (siRNA) enhanced the levels of fully glycosylated G1 and increased infectious LASV production. Finally, LASV particles produced from 25HC-treated cells were found to be less infectious, to incorporate aberrantly glycosylated GP1 species, and to be defective in binding alpha-dystroglycan, an attachment and entry receptor. Our findings identify a novel role for CH25H in controlling LASV propagation and indicate that manipulation of the expression of CH25H or the administration of 25HC may be a useful anti-LASV therapy. IMPORTANCE Lassa fever is an acute viral hemorrhagic fever in humans caused by Lassa virus (LASV). No vaccine for LASV is currently available. Treatment is limited to the administration of ribavirin, which is only effective when given early in the course of illness. Cholesterol 25-hydroxylase (CH25H) is a recently identified interferon-stimulated gene (ISG); it encodes an enzyme that catalyzes the production of 25-hydroxycholesterol (25HC), which inhibits several viruses. Here, we identify a novel antiviral mechanism of 25HC that is dependent on inhibiting the glycosylation of Lassa virus (LASV) glycoprotein and reducing the infectivity of LASV as a means of suppressing viral replication. Since N-linked glycosylation is a critical feature of other enveloped-virus glycoproteins, 25HC may be a broad inhibitor of virus infectivity.
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Affiliation(s)
- Punya Shrivastava-Ranjan
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Éric Bergeron
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Ayan K Chakrabarti
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - César G Albariño
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Mike Flint
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Stuart T Nichol
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Christina F Spiropoulou
- Viral Special Pathogens Branch, Division of High Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
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Collar AL, Clarke EC, Anaya E, Merrill D, Yarborough S, Anthony SM, Kuhn JH, Merle C, Theisen M, Bradfute SB. Comparison of N- and O-linked glycosylation patterns of ebolavirus glycoproteins. Virology 2016; 502:39-47. [PMID: 27984785 DOI: 10.1016/j.virol.2016.12.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 12/06/2016] [Accepted: 12/07/2016] [Indexed: 11/18/2022]
Abstract
Ebolaviruses are emerging pathogens that cause severe and often fatal viral hemorrhagic fevers. Four distinct ebolaviruses are known to cause Ebola virus disease in humans. The ebolavirus envelope glycoprotein (GP1,2) is heavily glycosylated, but the precise glycosylation patterns of ebolaviruses are largely unknown. Here we demonstrate that approximately 50 different N-glycan structures are present in GP1,2 derived from the four pathogenic ebolaviruses, including high mannose, hybrid, and bi-, tri-, and tetra-antennary complex glycans with and without fucose and sialic acid. The overall N-glycan composition is similar between the different ebolavirus GP1,2s. In contrast, the amount and type of O-glycan structures varies widely between ebolavirus GP1,2s. Notably, this O-glycan dissimilarity is also present between two variants of Ebola virus, the original Yambuku variant and the Makona variant responsible for the most recent Western African epidemic. The data presented here should serve as the foundation for future ebolaviral entry and immunogenicity studies.
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Affiliation(s)
- Amanda L Collar
- Center for Global Health, Division of Infectious Diseases, Department of Internal Medicine, University of New Mexico, Albuquerque, NM, USA
| | - Elizabeth C Clarke
- Center for Global Health, Division of Infectious Diseases, Department of Internal Medicine, University of New Mexico, Albuquerque, NM, USA
| | - Eduardo Anaya
- Department of Pathology, University of New Mexico, Albuquerque, NM, USA
| | - Denise Merrill
- Center for Global Health, Division of Infectious Diseases, Department of Internal Medicine, University of New Mexico, Albuquerque, NM, USA
| | - Sarah Yarborough
- Undergraduate Pipeline Network, University of New Mexico, Albuquerque, NM, USA
| | - Scott M Anthony
- Department of Microbiology, University of Iowa, Iowa City, IA, USA
| | - Jens H Kuhn
- Integrated Research Facility at Fort Detrick (IRF-Frederick), Division of Clinical Research (DCR), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Fort Detrick, Frederick, MD, USA
| | | | | | - Steven B Bradfute
- Center for Global Health, Division of Infectious Diseases, Department of Internal Medicine, University of New Mexico, Albuquerque, NM, USA.
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Wang W, Zhou Z, Zhang L, Wang S, Xiao G. Structure-function relationship of the mammarenavirus envelope glycoprotein. Virol Sin 2016; 31:380-394. [PMID: 27562602 DOI: 10.1007/s12250-016-3815-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 06/27/2016] [Indexed: 12/29/2022] Open
Abstract
Mammarenaviruses, including lethal pathogens such as Lassa virus and Junín virus, can cause severe hemorrhagic fever in humans. Entry is a key step for virus infection, which starts with binding of the envelope glycoprotein (GP) to receptors on target cells and subsequent fusion of the virus with target cell membranes. The GP precursor is synthesized as a polypeptide, and maturation occurs by two cleavage events, yielding a tripartite GP complex (GPC) formed by a stable signal peptide (SSP), GP1 and GP2. The unique retained SSP interacts with GP2 and plays essential roles in virion maturation and infectivity. GP1 is responsible for binding to the cell receptor, and GP2 is a class I fusion protein. The native structure of the tripartite GPC is unknown. GPC is critical for the receptor binding, membrane fusion and neutralization antibody recognition. Elucidating the molecular mechanisms underlining the structure-function relationship of the three subunits is the key for understanding their function and can facilitate novel avenues for combating virus infections. This review summarizes the basic aspects and recent research of the structure-function relationship of the three subunits. We discuss the structural basis of the receptor-binding domain in GP1, the interaction between SSP and GP2 and its role in virion maturation and membrane fusion, as well as the mechanism by which glycosylation stabilizes the GPC structure and facilitates immune evasion. Understanding the molecular mechanisms involved in these aspects will contribute to the development of novel vaccines and treatment strategies against mammarenaviruses infection.
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Affiliation(s)
- Wei Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China.
| | - Zheng Zhou
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Leike Zhang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Shaobo Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Gengfu Xiao
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
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Sommerstein R, Flatz L, Remy MM, Malinge P, Magistrelli G, Fischer N, Sahin M, Bergthaler A, Igonet S, ter Meulen J, Rigo D, Meda P, Rabah N, Coutard B, Bowden TA, Lambert PH, Siegrist CA, Pinschewer DD. Arenavirus Glycan Shield Promotes Neutralizing Antibody Evasion and Protracted Infection. PLoS Pathog 2015; 11:e1005276. [PMID: 26587982 PMCID: PMC4654586 DOI: 10.1371/journal.ppat.1005276] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 10/22/2015] [Indexed: 01/05/2023] Open
Abstract
Arenaviruses such as Lassa virus (LASV) can cause severe hemorrhagic fever in humans. As a major impediment to vaccine development, delayed and weak neutralizing antibody (nAb) responses represent a unifying characteristic of both natural infection and all vaccine candidates tested to date. To investigate the mechanisms underlying arenavirus nAb evasion we engineered several arenavirus envelope-chimeric viruses and glycan-deficient variants thereof. We performed neutralization tests with sera from experimentally infected mice and from LASV-convalescent human patients. NAb response kinetics in mice correlated inversely with the N-linked glycan density in the arenavirus envelope protein’s globular head. Additionally and most intriguingly, infection with fully glycosylated viruses elicited antibodies, which neutralized predominantly their glycan-deficient variants, both in mice and humans. Binding studies with monoclonal antibodies indicated that envelope glycans reduced nAb on-rate, occupancy and thereby counteracted virus neutralization. In infected mice, the envelope glycan shield promoted protracted viral infection by preventing its timely elimination by the ensuing antibody response. Thus, arenavirus envelope glycosylation impairs the protective efficacy rather than the induction of nAbs, and thereby prevents efficient antibody-mediated virus control. This immune evasion mechanism imposes limitations on antibody-based vaccination and convalescent serum therapy. Neutralizing antibodies (nAbs) represent a key principle of antiviral immunity. Protective vaccines aim at inducing nAbs to prevent viral infection, and infusion of nAbs in convalescent patient serum can offer a potent antiviral therapy. Certain viruses, however, have found ways to evade nAb control. Amongst them are high-risk pathogens of the arenavirus family such as Lassa virus (LASV), which is a frequent cause of hemorrhagic fever in West Africa. Here we unveil the molecular strategy by which arenaviruses escape antibody neutralization and avoid efficient immune control. We show that their surface is decorated with sugar moieties, serving to shield the virus against the neutralizing effect of the host’s antibodies. This immune evasion strategy differs from those described for other viruses, in which sugars impair primarily the induction of antibodies or allow for viral mutational escape. The arenavirus sugar coat renders the host nAb response inefficient and as a consequence thereof, the host fails to promptly control the infection. Our results offer a compelling explanation for the long history of failures in trying to make a nAb-based vaccine against LASV or in using convalescent serum for therapy. These mechanistic insights will support vaccine development efforts against arenaviruses such as LASV.
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Affiliation(s)
- Rami Sommerstein
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
- World Health Organization Collaborating Centre for Vaccine Immunology, University of Geneva, Geneva, Switzerland
| | - Lukas Flatz
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Melissa M. Remy
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
- Division of Experimental Virology, Department of Biomedicine, University of Basel, Basel, Switzerland
| | | | | | | | - Mehmet Sahin
- Division of Experimental Virology, Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Andreas Bergthaler
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Sebastien Igonet
- Institut Pasteur, Département de Virologie, Unité de Virologie Structurale and CNRS UMR 3569 Virologie, Paris, France
| | - Jan ter Meulen
- Institute of Virology, Philipps University Marburg, Marburg, Germany
| | - Dorothée Rigo
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Paolo Meda
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Nadia Rabah
- AFMB, UMR7257 CNRS/Aix Marseille Université, Marseille, France
| | - Bruno Coutard
- AFMB, UMR7257 CNRS/Aix Marseille Université, Marseille, France
| | - Thomas A. Bowden
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Paul-Henri Lambert
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
- World Health Organization Collaborating Centre for Vaccine Immunology, University of Geneva, Geneva, Switzerland
| | - Claire-Anne Siegrist
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
- World Health Organization Collaborating Centre for Vaccine Immunology, University of Geneva, Geneva, Switzerland
| | - Daniel D. Pinschewer
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
- World Health Organization Collaborating Centre for Vaccine Immunology, University of Geneva, Geneva, Switzerland
- Division of Experimental Virology, Department of Biomedicine, University of Basel, Basel, Switzerland
- * E-mail:
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Human hemorrhagic Fever causing arenaviruses: molecular mechanisms contributing to virus virulence and disease pathogenesis. Pathogens 2015; 4:283-306. [PMID: 26011826 PMCID: PMC4493475 DOI: 10.3390/pathogens4020283] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Revised: 05/11/2015] [Accepted: 05/14/2015] [Indexed: 12/22/2022] Open
Abstract
Arenaviruses include multiple human pathogens ranging from the low-risk lymphocytic choriomeningitis virus (LCMV) to highly virulent hemorrhagic fever (HF) causing viruses such as Lassa (LASV), Junin (JUNV), Machupo (MACV), Lujo (LUJV), Sabia (SABV), Guanarito (GTOV), and Chapare (CHPV), for which there are limited preventative and therapeutic measures. Why some arenaviruses can cause virulent human infections while others cannot, even though they are isolated from the same rodent hosts, is an enigma. Recent studies have revealed several potential pathogenic mechanisms of arenaviruses, including factors that increase viral replication capacity and suppress host innate immunity, which leads to high viremia and generalized immune suppression as the hallmarks of severe and lethal arenaviral HF diseases. This review summarizes current knowledge of the roles of each of the four viral proteins and some known cellular factors in the pathogenesis of arenaviral HF as well as of some human primary cell-culture and animal models that lend themselves to studying arenavirus-induced HF disease pathogenesis. Knowledge gained from these studies can be applied towards the development of novel therapeutics and vaccines against these deadly human pathogens.
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Abstract
UNLABELLED Several arenaviruses are known to cause viral hemorrhagic fever (VHF) in sub-Saharan Africa and South America, where VHF is a major public health and medical concern. The biosafety level 4 categorization of these arenaviruses restricts their use and has impeded biological studies, including therapeutic drug and/or vaccine development. Due to difficulties associated with handling live viruses, pseudotype viruses, which transiently bear arenavirus envelope proteins based on vesicular stomatitis virus (VSV) or retrovirus, have been developed as surrogate virus systems. Here, we report the development of a pseudotype VSV bearing each envelope protein of various species of arenaviruses (AREpv), including the newly identified Lujo virus (LUJV) and Chapare virus. Pseudotype arenaviruses generated in 293T cells exhibited high infectivity in various mammalian cell lines. The infections by New World and Old World AREpv were dependent on their receptors (human transferrin receptor 1 [hTfR1] and α-dystroglycan [αDG], respectively). However, infection by pseudotype VSV bearing the LUJV envelope protein (LUJpv) occurred independently of hTfR1 and αDG, indicating that LUJpv utilizes an unidentified receptor. The pH-dependent endocytosis of AREpv was confirmed by the use of lysosomotropic agents. The fusion of cells expressing these envelope proteins, except for those expressing the LUJV envelope protein, was induced by transient treatment at low pH values. LUJpv infectivity was inhibited by U18666A, a cholesterol transport inhibitor. Furthermore, the infectivity of LUJpv was significantly decreased in the Niemann-Pick C1 (NPC1)-deficient cell line, suggesting the necessity for NPC1 activity for efficient LUJpv infection. IMPORTANCE LUJV is a newly identified arenavirus associated with a VHF outbreak in southern Africa. Although cell entry for many arenaviruses has been studied, cell entry for LUJV has not been characterized. In this study, we found that LUJpv utilizes neither αDG nor hTfR1 as a receptor and found unique characteristics of LUJV glycoprotein in membrane fusion and cell entry. Proper exclusion of cholesterol or some kinds of lipids may play important roles in LUJpv cell entry.
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Abstract
UNLABELLED Ebola virus (EBOV) entry requires the virion surface-associated glycoprotein (GP) that is composed of a trimer of heterodimers (GP1/GP2). The GP1 subunit contains two heavily glycosylated domains, the glycan cap and the mucin-like domain (MLD). The glycan cap contains only N-linked glycans, whereas the MLD contains both N- and O-linked glycans. Site-directed mutagenesis was performed on EBOV GP1 to systematically disrupt N-linked glycan sites to gain an understanding of their role in GP structure and function. All 15 N-glycosylation sites of EBOV GP1 could be removed without compromising the expression of GP. The loss of these 15 glycosylation sites significantly enhanced pseudovirion transduction in Vero cells, which correlated with an increase in protease sensitivity. Interestingly, exposing the receptor-binding domain (RBD) by removing the glycan shield did not allow interaction with the endosomal receptor, NPC1, indicating that the glycan cap/MLD domains mask RBD residues required for binding. The effects of the loss of GP1 N-linked glycans on Ca(2+)-dependent (C-type) lectin (CLEC)-dependent transduction were complex, and the effect was unique for each of the CLECs tested. Surprisingly, EBOV entry into murine peritoneal macrophages was independent of GP1 N-glycans, suggesting that CLEC-GP1 N-glycan interactions are not required for entry into this important primary cell. Finally, the removal of all GP1 N-glycans outside the MLD enhanced antiserum and antibody sensitivity. In total, our results provide evidence that the conserved N-linked glycans on the EBOV GP1 core protect GP from antibody neutralization despite the negative impact the glycans have on viral entry efficiency. IMPORTANCE Filovirus outbreaks occur sporadically throughout central Africa, causing high fatality rates among the general public and health care workers. These unpredictable hemorrhagic fever outbreaks are caused by multiple species of Ebola viruses, as well as Marburg virus. While filovirus vaccines and therapeutics are being developed, there are no licensed products. The sole viral envelope glycoprotein, which is a principal immunogenic target, contains a heavy shield of glycans surrounding the conserved receptor-binding domain. We find that disruption of this shield through targeted mutagenesis leads to an increase in cell entry, protease sensitivity, and antiserum/antibody sensitivity but is not sufficient to allow virion binding to the intracellular receptor NPC1. Therefore, our studies provide evidence that filoviruses maintain glycoprotein glycosylation to protect against proteases and antibody neutralization at the expense of efficient entry. Our results unveil interesting insights into the unique entry process of filoviruses and potential immune evasion tactics of the virus.
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Fehling SK, Noda T, Maisner A, Lamp B, Conzelmann KK, Kawaoka Y, Klenk HD, Garten W, Strecker T. The microtubule motor protein KIF13A is involved in intracellular trafficking of the Lassa virus matrix protein Z. Cell Microbiol 2013; 15:315-34. [DOI: 10.1111/cmi.12095] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Revised: 11/30/2012] [Accepted: 12/17/2012] [Indexed: 12/27/2022]
Affiliation(s)
- Sarah Katharina Fehling
- Institute of Virology; Philipps-University Marburg; Hans-Meerwein-Str. 2; 35043 ; Marburg; Germany
| | | | - Andrea Maisner
- Institute of Virology; Philipps-University Marburg; Hans-Meerwein-Str. 2; 35043 ; Marburg; Germany
| | - Boris Lamp
- Institute of Virology; Philipps-University Marburg; Hans-Meerwein-Str. 2; 35043 ; Marburg; Germany
| | - Karl-Klaus Conzelmann
- Max von Pettenkofer-Institute and Gene Center; Ludwig-Maximilians-University Munich; 81377 ; Munich; Germany
| | | | - Hans-Dieter Klenk
- Institute of Virology; Philipps-University Marburg; Hans-Meerwein-Str. 2; 35043 ; Marburg; Germany
| | - Wolfgang Garten
- Institute of Virology; Philipps-University Marburg; Hans-Meerwein-Str. 2; 35043 ; Marburg; Germany
| | - Thomas Strecker
- Institute of Virology; Philipps-University Marburg; Hans-Meerwein-Str. 2; 35043 ; Marburg; Germany
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McLay L, Ansari A, Liang Y, Ly H. Targeting virulence mechanisms for the prevention and therapy of arenaviral hemorrhagic fever. Antiviral Res 2012; 97:81-92. [PMID: 23261843 DOI: 10.1016/j.antiviral.2012.12.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2012] [Revised: 11/28/2012] [Accepted: 12/07/2012] [Indexed: 11/28/2022]
Abstract
A number of arenaviruses are pathogenic for humans, but they differ significantly in virulence. Lassa virus, found in West Africa, causes severe hemorrhagic fever (HF), while the other principal Old World arenavirus, lymphocytic choriomeningitis virus, causes mild illness in persons with normal immune function, and poses a threat only to immunocompromised individuals. The New World agents, including Junin, Machupo and Sabia virus, are highly pathogenic for humans. Arenaviral HF is characterized by high viremia and general immune suppression, the mechanism of which is unknown. Studies using viral reverse genetics, cell-based assays, animal models and human genome-wide association analysis have revealed potential mechanisms by which arenaviruses cause severe disease in humans. Each of the four viral gene products (GPC, L polymerase, NP, and Z matrix protein) and several host-cell factors (e.g., α-dystroglycan) are responsible for mediating viral entry, genome replication, and the inhibition of apoptosis, translation and interferon-beta (IFNβ) production. This review summarizes current knowledge of the role of each viral protein and host factor in the pathogenesis of arenaviral HF. Insights from recent studies are being exploited for the development of novel therapies.
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Affiliation(s)
- Lisa McLay
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA 30322, United States
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Abstract
Arenaviruses include lethal human pathogens which pose serious public health threats. So far, no FDA approved vaccines are available against arenavirus infections, and therapeutic options are limited, making the identification of novel drug targets for the development of efficacious therapeutics an urgent need. Arenaviruses are comprised of two RNA genome segments and four proteins, the polymerase L, the envelope glycoprotein GP, the matrix protein Z, and the nucleoprotein NP. A crucial step in the arenavirus life-cycle is the biosynthesis and maturation of the GP precursor (GPC) by cellular signal peptidases and the cellular enzyme Subtilisin Kexin Isozyme-1 (SKI-1)/Site-1 Protease (S1P) yielding a tripartite mature GP complex formed by GP1/GP2 and a stable signal peptide (SSP). GPC cleavage by SKI-1/S1P is crucial for fusion competence and incorporation of mature GP into nascent budding virion particles. In a first part of our review, we cover basic aspects and newer developments in the biosynthesis of arenavirus GP and its molecular interaction with SKI-1/S1P. A second part will then highlight the potential of SKI-1/S1P-mediated processing of arenavirus GPC as a novel target for therapeutic intervention to combat human pathogenic arenaviruses.
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Abstract
Arenaviruses have a bisegmented negative-strand RNA genome, which encodes four viral proteins: GP and NP by the S segment and L and Z by the L segment. These four viral proteins possess multiple functions in infection, replication and release of progeny viruses from infected cells. The small RING finger protein, Z protein is a matrix protein that plays a central role in viral assembly and budding. Although all arenaviruses encode Z protein, amino acid sequence alignment showed a huge variety among the species, especially at the C-terminus where the L-domain is located. Recent publications have demonstrated the interactions between viral protein and viral protein, and viral protein and host cellular protein, which facilitate transportation and assembly of viral components to sites of virus egress. This review presents a summary of current knowledge regarding arenavirus assembly and budding, in comparison with other enveloped viruses. We also refer to the restriction of arenavirus production by the antiviral cellular factor, Tetherin/BST-2.
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Radoshitzky SR, Kuhn JH, de Kok-Mercado F, Jahrling PB, Bavari S. Drug discovery technologies and strategies for Machupo virus and other New World arenaviruses. Expert Opin Drug Discov 2012; 7:613-32. [PMID: 22607481 PMCID: PMC3426302 DOI: 10.1517/17460441.2012.687719] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
INTRODUCTION Seven arenaviruses cause viral hemorrhagic fever in humans: the Old World arenaviruses Lassa and Lujo, and the New World Clade B arenaviruses Machupo (MACV), Junín (JUNV), Guanarito (GTOV), Sabiá (SABV), and Chapare (CHPV). All of these viruses are Risk Group 4 biosafety pathogens. MACV causes human disease outbreak with high case-fatality rates. To date, at least 1,200 cases with ≈200 fatalities have been recorded. AREAS COVERED This review summarizes available systems and technologies for the identification of antivirals against MACV. Furthermore, the article summarizes animal models that have been used for the in vivo evaluation of novel inhibitors. The article highlights present treatments for arenaviral diseases and provides an overview of efficacious small molecules and other therapeutics reported to date. Finally, the article summarizes strategies to identify novel inhibitors for anti-arenaviral therapy. EXPERT OPINION New high-throughput approaches to quantitate infection rates of arenaviruses, as well as viruses modified to carry reporter genes, will accelerate compound screens and drug discovery efforts. RNAi, gene expression profiling and proteomics studies will identify host targets for therapeutic intervention. New discoveries in the cell entry mechanism of MACV and other arenaviruses as well as extensive structural studies of arenaviral L and NP could facilitate the rational design of antivirals effective against all pathogenic New World arenaviruses.
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Affiliation(s)
- Sheli R. Radoshitzky
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD 21702, USA
| | - Jens H. Kuhn
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, MD 21702, USA
| | - Fabian de Kok-Mercado
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, MD 21702, USA
| | - Peter B. Jahrling
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, MD 21702, USA
| | - Sina Bavari
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD 21702, USA
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The curious case of arenavirus entry, and its inhibition. Viruses 2012; 4:83-101. [PMID: 22355453 PMCID: PMC3280523 DOI: 10.3390/v4010083] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 12/07/2011] [Accepted: 01/05/2012] [Indexed: 11/17/2022] Open
Abstract
Arenaviruses comprise a diverse family of enveloped negative-strand RNA viruses that are endemic to specific rodent hosts worldwide. Several arenaviruses cause severe hemorrhagic fevers in humans, including Junín and Machupo viruses in South America and Lassa fever virus in western Africa. Arenavirus entry into the host cell is mediated by the envelope glycoprotein complex, GPC. The virion is endocytosed on binding to a cell-surface receptor, and membrane fusion is initiated in response to physiological acidification of the endosome. As with other class I virus fusion proteins, GPC-mediated membrane fusion is promoted through a regulated sequence of conformational changes leading to formation of the classical postfusion trimer-of-hairpins structure. GPC is, however, unique among the class I fusion proteins in that the mature complex retains a stable signal peptide (SSP) as a third subunit, in addition to the canonical receptor-binding and fusion proteins. We will review the curious properties of the tripartite GPC complex and describe evidence that SSP interacts with the fusion subunit to modulate pH-induced activation of membrane fusion. This unusual solution to maintaining the metastable prefusion state of GPC on the virion and activating the class I fusion cascade at acidic pH provides novel targets for antiviral intervention.
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Coordinate deletion of N-glycans from the heptad repeats of the fusion F protein of Newcastle disease virus yields a hyperfusogenic virus with increased replication, virulence, and immunogenicity. J Virol 2011; 86:2501-11. [PMID: 22205748 DOI: 10.1128/jvi.06380-11] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The role of N-linked glycosylation of the Newcastle disease virus (NDV) fusion (F) protein in viral replication and pathogenesis was examined by eliminating potential acceptor sites using a reverse genetics system for the moderately pathogenic strain Beaudette C (BC). The NDV-BC F protein contains six potential acceptor sites for N-linked glycosylation at residues 85, 191, 366, 447, 471, and 541 (sites Ng1 to Ng6, respectively). The sites at Ng2 and Ng5 are present in heptad repeat (HR) domains HR1 and HR2, respectively, and thus might affect fusion. Each N-glycosylation site was eliminated individually by replacing asparagine (N) with glutamine (Q), and a double mutant (Ng2 + 5) involving the two HR domains was also made. Each mutant was successfully recovered by reverse genetics except for the one involving Ng6, which is present in the cytoplasmic domain. All of the F proteins expressed by the recovered mutant viruses were efficiently cleaved and transported to the infected-cell surface. None of the individual mutations affected viral fusogenicity, but the double mutation at Ng2 and Ng5 in HR1 and HR2 increased fusogenicity >12-fold. The single mutations at sites Ng1, Ng2, and Ng5 resulted in modestly reduced multicycle growth in vitro. These three single mutations were also the most attenuating in eggs and 1-day-old chicks and were associated with decreased replication and spread in 2-week-old chickens. In contrast, the combination of the mutations at Ng2 and Ng5 yielded a virus that, compared to the BC parent, replicated >100-fold more efficiently in vitro, was more virulent in eggs and chicks, replicated more efficiently in chickens with enhanced tropism for the brain and gut, and elicited stronger humoral cell responses. These results illustrate the effects of N-glycosylation of the F protein on NDV pathobiology and suggest that the N-glycans in HR1 and HR2 coordinately downregulate viral fusion and virulence.
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García CC, Sepúlveda CS, Damonte EB. Novel therapeutic targets for arenavirus hemorrhagic fevers. Future Virol 2011. [DOI: 10.2217/fvl.10.65] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Several members of the family Arenaviridae can cause severe hemorrhagic fevers in humans, representing a serious public health problem in endemic areas of Africa and South America. The Lassa virus is the most prevalent and dangerous arenavirus, causing over 300,000 infections per year and several thousand deaths. Furthermore, pathogenic arenaviruses are considered as category A potential agents for bioterrorism. Based on the danger of arenaviruses for human health, the increased emergence of new viral species in recent years and the lack of effective tools for their control or prevention, the search for novel antiviral compounds effective against these pathogenic agents is a continuous demanding effort. This article focuses on novel strategies to identify inhibitors for arenavirus therapy, analyzing viral and host proteins essential for virus infection as potential targets for antiviral development.
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Affiliation(s)
- Cybele C García
- Laboratorio de Virología, Departamento de Química Biológica, Facultad de Ciencias Exactas & Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, Piso 4, 1428 Buenos Aires, Argentina
| | - Claudia S Sepúlveda
- Laboratorio de Virología, Departamento de Química Biológica, Facultad de Ciencias Exactas & Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, Piso 4, 1428 Buenos Aires, Argentina
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Glycosylation modulates arenavirus glycoprotein expression and function. Virology 2010; 409:223-33. [PMID: 21056893 DOI: 10.1016/j.virol.2010.10.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2010] [Revised: 06/17/2010] [Accepted: 10/06/2010] [Indexed: 11/20/2022]
Abstract
The glycoprotein of lymphocytic choriomeningitis virus (LCMV) contains nine potential N-linked glycosylation sites. We investigated the function of these N-glycosylations by using alanine-scanning mutagenesis. All the available sites were occupied on GP1 and two of three on GP2. N-linked glycan mutations at positions 87 and 97 on GP1 resulted in reduction of expression and absence of cleavage and were necessary for downstream functions, as confirmed by the loss of GP-mediated fusion activity with T87A and S97A mutants. In contrast, T234A and E379N/A381T mutants impaired GP-mediated cell fusion without altered expression or processing. Infectivity via virus-like particles required glycans and a cleaved glycoprotein. Glycosylation at the first site within GP2, not normally utilized by LCMV, exhibited increased VLP infectivity. We also confirmed the role of the N-linked glycan at position 173 in the masking of the neutralizing epitope GP-1D. Taken together, our results indicated a strong relationship between fusion and infectivity.
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Schlie K, Strecker T, Garten W. Maturation cleavage within the ectodomain of Lassa virus glycoprotein relies on stabilization by the cytoplasmic tail. FEBS Lett 2010; 584:4379-82. [PMID: 20875414 DOI: 10.1016/j.febslet.2010.09.032] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Revised: 09/13/2010] [Accepted: 09/20/2010] [Indexed: 10/19/2022]
Abstract
The Lassa virus glycoprotein consists of an ectodomain, a transmembrane anchor, and a cytoplasmic domain. It is synthesized as an inactive precursor and cleaved within the ectodomain to yield the mature form. Here, we show that this maturation cleavage can be abolished by mutation of single conserved amino acids within the cytoplasmic domain at the carboxy-terminus of the glycoprotein. Moreover, substitutions and deletions of multiple amino acids result in destabilization of the glycoprotein oligomers. These results indicate that conformation changes in the cytoplasmic domain travel across the membrane and subsequently abolish the maturation cleavage. Therefore, we postulate that the cytoplasmic domain is an important maturation factor stabilizing the overall conformation of the glycoprotein.
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Affiliation(s)
- Katrin Schlie
- Institute of Virology, Philipps University of Marburg, Marburg, Germany
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Characterization of Lassa virus glycoprotein oligomerization and influence of cholesterol on virus replication. J Virol 2009; 84:983-92. [PMID: 19889753 DOI: 10.1128/jvi.02039-09] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mature glycoprotein spikes are inserted in the Lassa virus envelope and consist of the distal subunit GP-1, the transmembrane-spanning subunit GP-2, and the signal peptide, which originate from the precursor glycoprotein pre-GP-C by proteolytic processing. In this study, we analyzed the oligomeric structure of the viral surface glycoprotein. Chemical cross-linking studies of mature glycoprotein spikes from purified virus revealed the formation of trimers. Interestingly, sucrose density gradient analysis of cellularly expressed glycoprotein showed that in contrast to trimeric mature glycoprotein complexes, the noncleaved glycoprotein forms monomers and oligomers spanning a wide size range, indicating that maturation cleavage of GP by the cellular subtilase SKI-1/S1P is critical for formation of the correct oligomeric state. To shed light on a potential relation between cholesterol and GP trimer stability, we performed cholesterol depletion experiments. Although depletion of cholesterol had no effect on trimerization of the glycoprotein spike complex, our studies revealed that the cholesterol content of the viral envelope is important for the infectivity of Lassa virus. Analyses of the distribution of viral proteins in cholesterol-rich detergent-resistant membrane areas showed that Lassa virus buds from membrane areas other than those responsible for impaired infectivity due to cholesterol depletion of lipid rafts. Thus, derivation of the viral envelope from cholesterol-rich membrane areas is not a prerequisite for the impact of cholesterol on virus infectivity.
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Nipah virus fusion protein: influence of cleavage site mutations on the cleavability by cathepsin L, trypsin and furin. Virus Res 2009; 145:300-6. [PMID: 19665506 PMCID: PMC7126315 DOI: 10.1016/j.virusres.2009.07.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2009] [Revised: 07/28/2009] [Accepted: 07/29/2009] [Indexed: 11/22/2022]
Abstract
Nipah virus (NiV), a highly pathogenic member of the Paramyxoviridae which originated from bats, encodes for a fusion (F) protein which is proteolytically processed within endosomes by cathepsin L. We show here that sequence requirements for NiV F activation differ markedly from other para- or orthomyxoviral fusion proteins. In contrast to other viral fusion proteins with monobasic cleavage sites, processing of NiV F proteins with one single basic amino acid in the cleavage peptide by exogenous trypsin is very inefficient, and introduction of a consensus sequence for furin does not result in cleavage by this ubiquitous protease. In contrast, a multibasic cleavage peptide in the NiV F protein completely impairs proteolytic processing and the generation of biological activity.
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