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Guo X, Zhang M, Liu X, Zhang Y, Wang C, Guo Y. Attachment, Entry, and Intracellular Trafficking of Classical Swine Fever Virus. Viruses 2023; 15:1870. [PMID: 37766277 PMCID: PMC10534341 DOI: 10.3390/v15091870] [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: 05/30/2023] [Revised: 08/29/2023] [Accepted: 08/29/2023] [Indexed: 09/29/2023] Open
Abstract
Classical swine fever virus (CSFV), which is a positive-sense, single-stranded RNA virus with an envelope, is a member of the Pestivirus genus in the Flaviviridae family. CSFV causes a severe and highly contagious disease in pigs and is prevalent worldwide, threatening the pig farming industry. The detailed mechanisms of the CSFV life cycle have been reported, but are still limited. Some receptors and attachment factors of CSFV, including heparan sulfate (HS), laminin receptor (LamR), complement regulatory protein (CD46), MER tyrosine kinase (MERTK), disintegrin, and metalloproteinase domain-containing protein 17 (ADAM17), were identified. After attachment, CSFV internalizes via clathrin-mediated endocytosis (CME) and/or caveolae/raft-dependent endocytosis (CavME). After internalization, CSFV moves to early and late endosomes before uncoating. During this period, intracellular trafficking of CSFV relies on components of the endosomal sorting complex required for transport (ESCRT) and Rab proteins in the endosome dynamics, with a dependence on the cytoskeleton network. This review summarizes the data on the mechanisms of CSFV attachment, internalization pathways, and intracellular trafficking, and provides a general view of the early events in the CSFV life cycle.
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Affiliation(s)
| | | | | | | | | | - Yidi Guo
- State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun 130012, China
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2
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Zhao X, Wang X, Yuan M, Zhang X, Yang X, Guan X, Li S, Ma J, Qiu HJ, Li Y. Identification of two novel T cell epitopes on the E2 protein of classical swine fever virus C-strain. Vet Microbiol 2023; 284:109814. [PMID: 37356277 DOI: 10.1016/j.vetmic.2023.109814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 06/11/2023] [Accepted: 06/14/2023] [Indexed: 06/27/2023]
Abstract
C-strain, also known as the HCLV strain, is a well-known live attenuated vaccine against classical swine fever (CSF), a devastating disease caused by classical swine fever virus (CSFV). Vaccination with C-strain induces a rapid onset of protection, which is associated with virus-specific gamma interferon (IFN-γ)-secreting CD8+ T cell responses. The E2 protein of CSFV is a major protective antigen. However, the T cell epitopes on the E2 protein remain largely unknown. In this study, eight overlapping nonapeptides of the E2 protein were predicted and synthesized to screen for potential T cell epitopes on the CSFV C-strain E2 protein. Molecular docking was performed on the candidate epitopes with the swine leukocyte antigen-1*0401. The analysis obtained two highly conserved T cell epitopes, 90STEEMGDDF98 and 331ATDRHSDYF339, which were further identified by enzyme-linked immunospot assay. Interestingly, the mutants deleting or substituting the epitopes are nonviable. Further analysis demonstrated that 90STEEMGDDF98 is crucial for the E2 homodimerization, while CSFV infection is significantly inhibited by the 331ATDRHSDYF339 peptide treatment. The two novel T cell epitopes can be used to design new vaccines that are able to provide rapid-onset protection.
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Affiliation(s)
- Xiaotian Zhao
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China; Tianjin Key Laboratory of Agricultural Animal Breeding and Healthy Husbandry, College of Animal Science and Veterinary Medicine, Tianjin Agricultural University, Tianjin, China
| | - Xiao Wang
- Department of Pathogenic Biology, School of Basic Medical Sciences, Binzhou Medical University, Yantai, China
| | - Mengqi Yuan
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Xin Zhang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Xiaoke Yang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Xiangyu Guan
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Shuwen Li
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Jifei Ma
- Tianjin Key Laboratory of Agricultural Animal Breeding and Healthy Husbandry, College of Animal Science and Veterinary Medicine, Tianjin Agricultural University, Tianjin, China.
| | - Hua-Ji Qiu
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
| | - Yongfeng Li
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
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Metcalf MC, Janus BM, Yin R, Wang R, Guest JD, Pozharski E, Law M, Mariuzza RA, Toth EA, Pierce BG, Fuerst TR, Ofek G. Structure of engineered hepatitis C virus E1E2 ectodomain in complex with neutralizing antibodies. Nat Commun 2023; 14:3980. [PMID: 37407593 PMCID: PMC10322937 DOI: 10.1038/s41467-023-39659-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: 01/27/2023] [Accepted: 06/22/2023] [Indexed: 07/07/2023] Open
Abstract
Hepatitis C virus (HCV) is a major global health burden as the leading causative agent of chronic liver disease and hepatocellular carcinoma. While the main antigenic target for HCV-neutralizing antibodies is the membrane-associated E1E2 surface glycoprotein, the development of effective vaccines has been hindered by complications in the biochemical preparation of soluble E1E2 ectodomains. Here, we present a cryo-EM structure of an engineered, secreted E1E2 ectodomain of genotype 1b in complex with neutralizing antibodies AR4A, HEPC74, and IGH520. Structural characterization of the E1 subunit and C-terminal regions of E2 reveal an overall architecture of E1E2 that concurs with that observed for non-engineered full-length E1E2. Analysis of the AR4A epitope within a region of E2 that bridges between the E2 core and E1 defines the structural basis for its broad neutralization. Our study presents the structure of an E1E2 complex liberated from membrane via a designed scaffold, one that maintains all essential structural features of native E1E2. The study advances the understanding of the E1E2 heterodimer structure, crucial for the rational design of secreted E1E2 antigens in vaccine development.
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Affiliation(s)
- Matthew C Metcalf
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, USA
| | - Benjamin M Janus
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, USA
| | - Rui Yin
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, USA
| | - Ruixue Wang
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, USA
| | - Johnathan D Guest
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, USA
| | - Edwin Pozharski
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, USA
- Center for Biomolecular Therapeutics, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Mansun Law
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, USA
| | - Roy A Mariuzza
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, USA
| | - Eric A Toth
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, USA
| | - Brian G Pierce
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, USA
| | - Thomas R Fuerst
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, USA
| | - Gilad Ofek
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA.
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, USA.
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Abstract
Viral fusion glycoproteins catalyze membrane fusion during viral entry. Unlike most enzymes, however, they lack a conventional active site in which formation or scission of a specific covalent bond is catalyzed. Instead, they drive the membrane fusion reaction by cojoining highly regulated changes in conformation to membrane deformation. Despite the challenges in applying inhibitor design approaches to these proteins, recent advances in knowledge of the structures and mechanisms of viral fusogens have enabled the development of small-molecule inhibitors of both class I and class II viral fusion proteins. Here, we review well-validated inhibitors, including their discovery, targets, and mechanism(s) of action, while highlighting mechanistic similarities and differences. Together, these examples make a compelling case for small-molecule inhibitors as tools for probing the mechanisms of viral glycoprotein-mediated fusion and for viral glycoproteins as druggable targets.
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Affiliation(s)
- Han-Yuan Liu
- Department of Microbiology and Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
- Current affiliation: Department of Microbiology and Immunology, Stanford University School of Medicine, Palo Alto, California 94305, USA;
| | - Priscilla L Yang
- Department of Microbiology and Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
- Current affiliation: Department of Microbiology and Immunology, Stanford University School of Medicine, Palo Alto, California 94305, USA;
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Lozada C, Barlow TMA, Gonzalez S, Lubin-Germain N, Ballet S. Identification and Characteristics of Fusion Peptides Derived From Enveloped Viruses. Front Chem 2021; 9:689006. [PMID: 34497798 PMCID: PMC8419435 DOI: 10.3389/fchem.2021.689006] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 08/10/2021] [Indexed: 01/28/2023] Open
Abstract
Membrane fusion events allow enveloped viruses to enter and infect cells. The study of these processes has led to the identification of a number of proteins that mediate this process. These proteins are classified according to their structure, which vary according to the viral genealogy. To date, three classes of fusion proteins have been defined, but current evidence points to the existence of additional classes. Despite their structural differences, viral fusion processes follow a common mechanism through which they exert their actions. Additional studies of the viral fusion proteins have demonstrated the key role of specific proteinogenic subsequences within these proteins, termed fusion peptides. Such peptides are able to interact and insert into membranes for which they hold interest from a pharmacological or therapeutic viewpoint. Here, the different characteristics of fusion peptides derived from viral fusion proteins are described. These criteria are useful to identify new fusion peptides. Moreover, this review describes the requirements of synthetic fusion peptides derived from fusion proteins to induce fusion by themselves. Several sequences of the viral glycoproteins E1 and E2 of HCV were, for example, identified to be able to induce fusion, which are reviewed here.
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Affiliation(s)
- Camille Lozada
- BioCIS, CNRS, CY Cergy-Paris Université, Cergy-Pontoise, France
- Research Group of Organic Chemistry, Vrije Universiteit Brussel, Brussels, Belgium
| | - Thomas M. A. Barlow
- Research Group of Organic Chemistry, Vrije Universiteit Brussel, Brussels, Belgium
| | - Simon Gonzalez
- BioCIS, CNRS, CY Cergy-Paris Université, Cergy-Pontoise, France
| | | | - Steven Ballet
- Research Group of Organic Chemistry, Vrije Universiteit Brussel, Brussels, Belgium
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Hepatitis C Virus Entry: An Intriguingly Complex and Highly Regulated Process. Int J Mol Sci 2020; 21:ijms21062091. [PMID: 32197477 PMCID: PMC7140000 DOI: 10.3390/ijms21062091] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 03/15/2020] [Accepted: 03/16/2020] [Indexed: 02/07/2023] Open
Abstract
Hepatitis C virus (HCV) is a major cause of chronic hepatitis and liver disease worldwide. Its tissue and species tropism are largely defined by the viral entry process that is required for subsequent productive viral infection and establishment of chronic infection. This review provides an overview of the viral and host factors involved in HCV entry into hepatocytes, summarizes our understanding of the molecular mechanisms governing this process and highlights the therapeutic potential of host-targeting entry inhibitors.
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Li D, Wu J, Chen J, Zhang D, Zhang Y, Qiao X, Yu X, Zheng Q, Hou J. Optimized expression of classical swine fever virus E2 protein via combined strategy in Pichia pastoris. Protein Expr Purif 2019; 167:105527. [PMID: 31678666 DOI: 10.1016/j.pep.2019.105527] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 10/09/2019] [Accepted: 10/30/2019] [Indexed: 10/25/2022]
Abstract
Precaution of classical swine fever (CSF) is an important mission for the worldwide swine industry. Glycoprotein E2 is the leading antigen candidate for subunit vaccine of classical swine fever virus (CSFV). In this study, two Spy-tagged E2 genes were synthesized in vitro and subcloned into pMCO-AOX vector for intracellular expression in Pichia pastoris after methanol induction. Western blot analysis and semi-quantitative analysis showed that the yield of recombinant E2 protein was improved 17.87 folds by using co-translocational signal peptide cSIG. After the construction of the tandem multiple copy expression vectors, further increase of E2 production was observed by repetitive transforming expression vectors into P. pastoris genome. Finally, the yeast transformants harboring 8 or 16 copies of cSIG-E2-Spy increased the E2 expression level by 27.01-fold or 30.72-fold, respectively. These results demonstrate that utilizing co-translocational signal peptide together with multi-copy integration strategy can increase the production of recombinant E2 protein efficiently.
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Affiliation(s)
- Ding Li
- Institute of Veterinary Immunology & Engineering, Jiangsu Academy of Agricultural Sciences, Jiangsu, China; Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonose, Yangzhou University, Jiangsu, China; Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology, China
| | - Junchen Wu
- Institute of Veterinary Immunology & Engineering, Jiangsu Academy of Agricultural Sciences, Jiangsu, China; Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonose, Yangzhou University, Jiangsu, China; Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology, China
| | - Jin Chen
- Institute of Veterinary Immunology & Engineering, Jiangsu Academy of Agricultural Sciences, Jiangsu, China; Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonose, Yangzhou University, Jiangsu, China; Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology, China
| | - Dong Zhang
- Shandong Provincial Center for Animal Disease Control and Prevention, Shandong, China
| | - Yuanpeng Zhang
- Institute of Veterinary Immunology & Engineering, Jiangsu Academy of Agricultural Sciences, Jiangsu, China; Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonose, Yangzhou University, Jiangsu, China; Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology, China
| | - Xuwen Qiao
- Institute of Veterinary Immunology & Engineering, Jiangsu Academy of Agricultural Sciences, Jiangsu, China; Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonose, Yangzhou University, Jiangsu, China; Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology, China
| | - Xiaoming Yu
- Institute of Veterinary Immunology & Engineering, Jiangsu Academy of Agricultural Sciences, Jiangsu, China; Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonose, Yangzhou University, Jiangsu, China; Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology, China
| | - Qisheng Zheng
- Institute of Veterinary Immunology & Engineering, Jiangsu Academy of Agricultural Sciences, Jiangsu, China; Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonose, Yangzhou University, Jiangsu, China; Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology, China.
| | - Jibo Hou
- Institute of Veterinary Immunology & Engineering, Jiangsu Academy of Agricultural Sciences, Jiangsu, China; Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonose, Yangzhou University, Jiangsu, China; Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology, China.
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8
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Comparative Phylogenetic and Residue Analysis of Hepatitis C Virus E1 Protein from the Middle East and North Africa Region. HEPATITIS MONTHLY 2019. [DOI: 10.5812/hepatmon.92437] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
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Banda DH, Perin PM, Brown RJP, Todt D, Solodenko W, Hoffmeyer P, Kumar Sahu K, Houghton M, Meuleman P, Müller R, Kirschning A, Pietschmann T. A central hydrophobic E1 region controls the pH range of hepatitis C virus membrane fusion and susceptibility to fusion inhibitors. J Hepatol 2019; 70:1082-1092. [PMID: 30769006 DOI: 10.1016/j.jhep.2019.01.033] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 01/14/2019] [Accepted: 01/29/2019] [Indexed: 02/09/2023]
Abstract
BACKGROUND & AIMS Hepatitis C virus (HCV) infection causes chronic liver disease. Antivirals have been developed and cure infection. However, resistance can emerge and salvage therapies with alternative modes of action could be useful. Several licensed drugs have emerged as HCV entry inhibitors and are thus candidates for drug repurposing. We aimed to dissect their mode of action, identify improved derivatives and determine their viral targets. METHODS HCV entry inhibition was tested for a panel of structurally related compounds, using chimeric viruses representing diverse genotypes, in addition to viruses containing previously determined resistance mutations. Chemical modeling and synthesis identified improved derivatives, while generation of susceptible and non-susceptible chimeric viruses pinpointed E1 determinants of compound sensitivity. RESULTS Molecules of the diphenylpiperazine, diphenylpiperidine, phenothiazine, thioxanthene, and cycloheptenepiperidine chemotypes inhibit HCV infection by interfering with membrane fusion. These molecules and a novel p-methoxy-flunarizine derivative with improved efficacy preferentially inhibit genotype 2 viral strains. Viral residues within a central hydrophobic region of E1 (residues 290-312) control susceptibility. At the same time, viral features in this region also govern pH-dependence of viral membrane fusion. CONCLUSIONS Small molecules from different chemotypes related to flunarizine preferentially inhibit HCV genotype 2 membrane fusion. A hydrophobic region proximal to the putative fusion loop controls sensitivity to these drugs and the pH range of membrane fusion. An algorithm considering viral features in this region predicts viral sensitivity to membrane fusion inhibitors. Resistance to flunarizine correlates with more relaxed pH requirements for fusion. LAY SUMMARY This study describes diverse compounds that act as HCV membrane fusion inhibitors. It defines viral properties that determine sensitivity to these molecules and thus provides information to identify patients that may benefit from treatment with membrane fusion inhibitors.
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Affiliation(s)
- Dominic H Banda
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, a joint venture between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Feodor-Lynen-Str. 7, 30625 Hannover, Germany
| | - Paula M Perin
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, a joint venture between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Feodor-Lynen-Str. 7, 30625 Hannover, Germany
| | - Richard J P Brown
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, a joint venture between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Feodor-Lynen-Str. 7, 30625 Hannover, Germany
| | - Daniel Todt
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, a joint venture between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Feodor-Lynen-Str. 7, 30625 Hannover, Germany; Department of Molecular and Medical Virology, Ruhr University Bochum, Bochum, Germany
| | - Wladimir Solodenko
- Institute of Organic Chemistry and Center of Biomolecular Drug Research (BMWZ), Leibniz Universität, Hannover, Germany
| | - Patrick Hoffmeyer
- Institute of Organic Chemistry and Center of Biomolecular Drug Research (BMWZ), Leibniz Universität, Hannover, Germany
| | - Kamlesh Kumar Sahu
- Li Ka Shing Institute of Virology, Department of Medical Microbiology & Immunology, University of Alberta, Edmonton, Canada
| | - Michael Houghton
- Li Ka Shing Institute of Virology, Department of Medical Microbiology & Immunology, University of Alberta, Edmonton, Canada
| | - Philip Meuleman
- Laboratory of Liver Infectious Diseases, Ghent University, Ghent, Belgium
| | - Rolf Müller
- Helmholtz Institute for Pharmaceutical Research Saarland, Saarbrücken, Germany
| | - Andreas Kirschning
- Institute of Organic Chemistry and Center of Biomolecular Drug Research (BMWZ), Leibniz Universität, Hannover, Germany
| | - Thomas Pietschmann
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, a joint venture between the Medical School Hannover (MHH) and the Helmholtz Centre for Infection Research (HZI), Feodor-Lynen-Str. 7, 30625 Hannover, Germany; German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, 30625 Hannover, Germany.
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10
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Cao L, Yu B, Kong D, Cong Q, Yu T, Chen Z, Hu Z, Chang H, Zhong J, Baker D, He Y. Functional expression and characterization of the envelope glycoprotein E1E2 heterodimer of hepatitis C virus. PLoS Pathog 2019; 15:e1007759. [PMID: 31116791 PMCID: PMC6530877 DOI: 10.1371/journal.ppat.1007759] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 04/12/2019] [Indexed: 12/11/2022] Open
Abstract
Hepatitis C virus (HCV) is a member of Hepacivirus and belongs to the family of Flaviviridae. HCV infects millions of people worldwide and may lead to cirrhosis and hepatocellular carcinoma. HCV envelope proteins, E1 and E2, play critical roles in viral cell entry and act as major epitopes for neutralizing antibodies. However, unlike other known flaviviruses, it has been challenging to study HCV envelope proteins E1E2 in the past decades as the in vitro expressed E1E2 heterodimers are usually of poor quality, making the structural and functional characterization difficult. Here we express the ectodomains of HCV E1E2 heterodimer with either an Fc-tag or a de novo designed heterodimeric tag and are able to isolate soluble E1E2 heterodimer suitable for functional and structural studies. Then we characterize the E1E2 heterodimer by electron microscopy and model the structure by the coevolution based modeling strategy with Rosetta, revealing the potential interactions between E1 and E2. Moreover, the E1E2 heterodimer is applied to examine the interactions with the known HCV receptors, neutralizing antibodies as well as the inhibition of HCV infection, confirming the functionality of the E1E2 heterodimer and the binding profiles of E1E2 with the cellular receptors. Therefore, the expressed E1E2 heterodimer would be a valuable target for both viral studies and vaccination against HCV. Hepatitis C virus (HCV) is an enveloped virus that infects millions of people worldwide and may lead to cirrhosis and hepatocellular carcinoma. HCV has two envelope proteins, E1 and E2, which form heterodimers on viral surface and are critical for HCV cell entry. However, current studies of HCV E1E2 are often limited by the poor quality of the in vitro expressed E1E2 heterodimers. Here we express the ectodomains of HCV E1E2 with different tags, and are able to isolate soluble E1E2 ectodomains suitable for structural and functional studies. Then we generate the 3D reconstruction of E1E2 heterodimer by electron microscopy and also model the E1E2 structure by the coevolution based strategy with Rosetta, showing the potential interactions between E1 and E2. Moreover, the E1E2 heterodimer is applied to examine the interactions with the HCV cellular receptors, neutralizing antibodies as well as the inhibition of HCV infection. These results suggest that the expressed E1E2 heterodimer would be a promising target for both viral studies and vaccination against HCV.
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Affiliation(s)
- Longxing Cao
- State Key Laboratory of Molecular Biology, National Center for Protein Science Shanghai, Shanghai Science Research Center, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
- Institute for Protein Design, University of Washington, Seattle, Washington, United States of America
| | - Bowen Yu
- State Key Laboratory of Molecular Biology, National Center for Protein Science Shanghai, Shanghai Science Research Center, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
| | - Dandan Kong
- State Key Laboratory of Molecular Biology, National Center for Protein Science Shanghai, Shanghai Science Research Center, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
| | - Qian Cong
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
- Institute for Protein Design, University of Washington, Seattle, Washington, United States of America
| | - Tao Yu
- CAS Key Laboratory of Molecular Virology and Immunology, Unit of Viral Hepatitis, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Zibo Chen
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
- Institute for Protein Design, University of Washington, Seattle, Washington, United States of America
| | - Zhenzheng Hu
- State Key Laboratory of Molecular Biology, National Center for Protein Science Shanghai, Shanghai Science Research Center, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
| | - Haishuang Chang
- State Key Laboratory of Molecular Biology, National Center for Protein Science Shanghai, Shanghai Science Research Center, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
| | - Jin Zhong
- CAS Key Laboratory of Molecular Virology and Immunology, Unit of Viral Hepatitis, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - David Baker
- Department of Biochemistry, University of Washington, Seattle, Washington, United States of America
- Institute for Protein Design, University of Washington, Seattle, Washington, United States of America
- Howard Hughes Medical Institute, University of Washington, Seattle, Washington, United States of America
| | - Yongning He
- State Key Laboratory of Molecular Biology, National Center for Protein Science Shanghai, Shanghai Science Research Center, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai, China
- * E-mail:
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11
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Moustafa RI, Dubuisson J, Lavie M. Function of the HCV E1 envelope glycoprotein in viral entry and assembly. Future Virol 2019. [DOI: 10.2217/fvl-2018-0180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
HCV envelope glycoproteins, E1 and E2, are multifunctional proteins. Until recently, E2 glycoprotein was thought to be the fusion protein and was the focus of investigations. However, the recently obtained partial structures of E2 and E1 rather support a role for E1 alone or in association with E2 in HCV fusion. Moreover, they suggest that HCV harbors a new fusion mechanism, distinct from that of other members of the Flaviviridae family. In this context, E1 aroused a renewed interest. Recent functional characterizations of E1 revealed a more important role than previously thought in entry and assembly. Thus, E1 is involved in the viral genome encapsidation step and influences the association of the virus with lipoprotein components. Moreover, E1 modulates HCV–receptor interaction and participates in a late entry step potentially fusion. In this review, we outline our current knowledge on E1 functions in HCV assembly and entry.
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Affiliation(s)
- Rehab I Moustafa
- Université de Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 – UMR 8204 – CIIL– Centre d'Infection et d'Immunité de Lille, F-59000 Lille, France
- Department of Microbial Biotechnology, Genetic Engineering & Biotechnology Division, National Research Center, Dokki, Cairo, Egypt
| | - Jean Dubuisson
- Université de Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 – UMR 8204 – CIIL– Centre d'Infection et d'Immunité de Lille, F-59000 Lille, France
| | - Muriel Lavie
- Université de Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 – UMR 8204 – CIIL– Centre d'Infection et d'Immunité de Lille, F-59000 Lille, France
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12
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Gonzalez S, Gallier F, Kellouche S, Carreiras F, Novellino E, Carotenuto A, Chassaing G, Rovero P, Uziel J, Lubin-Germain N. Studies of membranotropic and fusogenic activity of two putative HCV fusion peptides. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1861:50-61. [PMID: 30343120 DOI: 10.1016/j.bbamem.2018.10.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 10/16/2018] [Accepted: 10/17/2018] [Indexed: 11/19/2022]
Abstract
Over the past decades, membranotropic peptides such as positively charged cell-penetrating peptides (CPPs) or amphipathic antimicrobial peptides (AMPs) have received increasing interest in order to improve therapeutic agent cellular uptake. As far as we are concerned, we were interested in studying HCV fusion peptides as putative anchors. Two peptides, HCV6 and HCV7, were identified and conjugated to a fluorescent tag NBD and tested for their interaction with liposomes as model membranes. DSC and spectrofluorescence analyses demonstrate HCV7 propensity to insert or internalize in vesicles containing anionic lipids DMPG whereas no activity was observed with zwitterionic DMPC. This behavior could be explained by the peptide sequence containing a cationic arginine residue. On the contrary, HCV6 did not exhibit any membranotropic activity but was the only sequence able to induce liposomes' fusion or aggregation monitored by spectrofluorescence and DLS. This two peptides mild activity was related to their inefficient structuration in contact with membrane mimetics, which was demonstrated by CD and NMR experiments. Altogether, our data allowed us to identify two promising membrane-active peptides from E1 and E2 HCV viral proteins, one fusogenic (HCV6) and the other membranotropic (HCV7). The latter was also confirmed by fluorescence microscopy with CHO cells, indicating that HCV7 could cross the plasma membrane via an endocytosis process. Therefore, this study provides new evidences supporting the identification of HCV6 as the HCV fusion peptide as well as insights on a novel membranotropic peptide from the HCV-E2 viral protein.
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Affiliation(s)
- Simon Gonzalez
- Laboratoire de Chimie Biologique, University of Cergy-Pontoise, 5 mail Gay-Lussac, Cergy-Pontoise, France
| | - Florian Gallier
- Laboratoire de Chimie Biologique, University of Cergy-Pontoise, 5 mail Gay-Lussac, Cergy-Pontoise, France
| | - Sabrina Kellouche
- Equipe de Recherche sur les Relations Matrice Extracellulaire-Cellules, ERRMECe (EA1391), Institut des Matériaux, I-MAT (FD4122), University of Cergy-Pontoise, MIR, rue Descartes, 95031, Neuville sur Oise Cedex, France
| | - Franck Carreiras
- Equipe de Recherche sur les Relations Matrice Extracellulaire-Cellules, ERRMECe (EA1391), Institut des Matériaux, I-MAT (FD4122), University of Cergy-Pontoise, MIR, rue Descartes, 95031, Neuville sur Oise Cedex, France
| | - Ettore Novellino
- Department of Pharmacy, University of Naples 'Federico II', Naples 80131, Italy
| | - Alfonso Carotenuto
- Department of Pharmacy, University of Naples 'Federico II', Naples 80131, Italy
| | - Gérard Chassaing
- Sorbonne Universités, UPMC University Paris 06, LBM, 4 place Jussieu, F-75005 Paris, France
| | - Paolo Rovero
- French-Italian Interdepartmental Laboratory of Peptide and Protein Chemistry and Biology, University of Florence, 50019 Sesto Fiorentino, Italy
| | - Jacques Uziel
- Laboratoire de Chimie Biologique, University of Cergy-Pontoise, 5 mail Gay-Lussac, Cergy-Pontoise, France
| | - Nadège Lubin-Germain
- Laboratoire de Chimie Biologique, University of Cergy-Pontoise, 5 mail Gay-Lussac, Cergy-Pontoise, France.
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13
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Moustafa RI, Haddad JG, Linna L, Hanoulle X, Descamps V, Mesalam AA, Baumert TF, Duverlie G, Meuleman P, Dubuisson J, Lavie M. Functional Study of the C-Terminal Part of the Hepatitis C Virus E1 Ectodomain. J Virol 2018; 92:e00939-18. [PMID: 30068644 PMCID: PMC6158422 DOI: 10.1128/jvi.00939-18] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 07/26/2018] [Indexed: 12/24/2022] Open
Abstract
In the hepatitis C virus (HCV) envelope glycoproteins E1 and E2, which form a heterodimer, E2 is the receptor binding protein and the major target of neutralizing antibodies, whereas the function of E1 remains less characterized. To investigate E1 functions, we generated a series of mutants in the conserved residues of the C-terminal region of the E1 ectodomain in the context of an infectious clone. We focused our analyses on two regions of interest. The first region is located in the middle of the E1 glycoprotein (between amino acid [aa] 270 and aa 291), which contains a conserved hydrophobic sequence and was proposed to constitute a putative fusion peptide. The second series of mutants was generated in the region from aa 314 to aa 342 (the aa314-342 region), which has been shown to contain two α helices (α2 and α3) by nuclear magnetic resonance studies. Of the 22 generated mutants, 20 were either attenuated or noninfectious. Several mutations modulated the virus's dependence on claudin-1 and the scavenger receptor BI coreceptors for entry. Most of the mutations in the putative fusion peptide region affected virus assembly. Conversely, mutations in the α-helix aa 315 to 324 (315-324) residues M318, W320, D321, and M322 resulted in a complete loss of infectivity without any impact on E1E2 folding and on viral assembly. Further characterization of the W320A mutant in the HCVpp model indicated that the loss of infectivity was due to a defect in viral entry. Together, these results support a role for E1 in modulating HCV interaction with its coreceptors and in HCV assembly. They also highlight the involvement of α-helix 315-324 in a late step of HCV entry.IMPORTANCE HCV is a major public health problem worldwide. The virion harbors two envelope proteins, E1 and E2, which are involved at different steps of the viral life cycle. Whereas E2 has been extensively characterized, the function of E1 remains poorly defined. We characterized here the function of the putative fusion peptide and the region containing α helices of the E1 ectodomain, which had been previously suggested to be important for virus entry. We could confirm the importance of these regions for the virus infectivity. Interestingly, we found several residues modulating the virus's dependence on several HCV receptors, thus highlighting the role of E1 in the interaction of the virus with cellular receptors. Whereas mutations in the putative fusion peptide affected HCV infectivity and morphogenesis, several mutations in the α2-helix region led to a loss of infectivity with no effect on assembly, indicating a role of this region in virus entry.
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Affiliation(s)
- Rehab I Moustafa
- University Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019-UMR 8204-CIIL/Centre d'Infection et d'Immunité de Lille, Lille, France
- Department of Microbial Biotechnology, Genetic Engineering and Biotechnology Division, National Research Centre, Dokki, Cairo, Egypt
| | - Juliano G Haddad
- University Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019-UMR 8204-CIIL/Centre d'Infection et d'Immunité de Lille, Lille, France
- Laboratoire Microbiologie Santé et Environnement, Ecole Doctorale en Sciences et Technologie, Faculté de Santé Publique, Université Libanaise, Tripoli, Liban
| | - Lydia Linna
- University Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019-UMR 8204-CIIL/Centre d'Infection et d'Immunité de Lille, Lille, France
| | - Xavier Hanoulle
- University of Lille, CNRS, UMR 8576, Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Véronique Descamps
- Equipe AGIR EA4294, Laboratoire de Virologie du Centre Hospitalier Universitaire d'Amiens, Université de Picardie Jules Verne, Amiens, France
| | - Ahmed Atef Mesalam
- Department of Clinical Chemistry, Microbiology and Immunology, Ghent University, Ghent, Belgium
- Department of Therapeutic Chemistry, National Research Centre, Dokki, Cairo, Egypt
- Research Group Immune- and Bio-markers for Infection, Centre of Excellence for Advanced Sciences, National Research Centre, Dokki, Cairo, Egypt
| | - Thomas F Baumert
- INSERM, U1110, University of Strasbourg, Pôle Hépato-digestif-Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Gilles Duverlie
- Equipe AGIR EA4294, Laboratoire de Virologie du Centre Hospitalier Universitaire d'Amiens, Université de Picardie Jules Verne, Amiens, France
| | - Philip Meuleman
- Department of Clinical Chemistry, Microbiology and Immunology, Ghent University, Ghent, Belgium
| | - Jean Dubuisson
- University Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019-UMR 8204-CIIL/Centre d'Infection et d'Immunité de Lille, Lille, France
| | - Muriel Lavie
- University Lille, CNRS, INSERM, CHU Lille, Institut Pasteur de Lille, U1019-UMR 8204-CIIL/Centre d'Infection et d'Immunité de Lille, Lille, France
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14
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Tong Y, Lavillette D, Li Q, Zhong J. Role of Hepatitis C Virus Envelope Glycoprotein E1 in Virus Entry and Assembly. Front Immunol 2018; 9:1411. [PMID: 29971069 PMCID: PMC6018474 DOI: 10.3389/fimmu.2018.01411] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 06/06/2018] [Indexed: 12/22/2022] Open
Abstract
Hepatitis C virus (HCV) glycoproteins E1 and E2 form a heterodimer to constitute viral envelope proteins, which play an essential role in virus entry. E1 does not directly interact with host receptors, and its functions in viral entry are exerted mostly through its interaction with E2 that directly binds the receptors. HCV enters the host cell via receptor-mediated endocytosis during which the fusion of viral and host endosomal membranes occurs to release viral genome to cytoplasm. A putative fusion peptide in E1 has been proposed to participate in membrane fusion, but its exact role and underlying molecular mechanisms remain to be deciphered. Recently solved crystal structures of the E2 ectodomains and N-terminal of E1 fail to reveal a classical fusion-like structure in HCV envelope glycoproteins. In addition, accumulating evidence suggests that E1 also plays an important role in virus assembly. In this mini-review, we summarize current knowledge on HCV E1 including its structure and biological functions in virus entry, fusion, and assembly, which may provide clues for developing HCV vaccines and more effective antivirals.
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Affiliation(s)
- Yimin Tong
- Unit of Viral Hepatitis, CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Dimitri Lavillette
- Unit of Interspecies Transmission of Arboviruses and Antivirals, CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Qingchao Li
- Unit of Viral Hepatitis, CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Jin Zhong
- Unit of Viral Hepatitis, CAS Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
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15
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Douam F, Fusil F, Enguehard M, Dib L, Nadalin F, Schwaller L, Hrebikova G, Mancip J, Mailly L, Montserret R, Ding Q, Maisse C, Carlot E, Xu K, Verhoeyen E, Baumert TF, Ploss A, Carbone A, Cosset FL, Lavillette D. A protein coevolution method uncovers critical features of the Hepatitis C Virus fusion mechanism. PLoS Pathog 2018; 14:e1006908. [PMID: 29505618 PMCID: PMC5854445 DOI: 10.1371/journal.ppat.1006908] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 03/15/2018] [Accepted: 01/26/2018] [Indexed: 12/15/2022] Open
Abstract
Amino-acid coevolution can be referred to mutational compensatory patterns preserving the function of a protein. Viral envelope glycoproteins, which mediate entry of enveloped viruses into their host cells, are shaped by coevolution signals that confer to viruses the plasticity to evade neutralizing antibodies without altering viral entry mechanisms. The functions and structures of the two envelope glycoproteins of the Hepatitis C Virus (HCV), E1 and E2, are poorly described. Especially, how these two proteins mediate the HCV fusion process between the viral and the cell membrane remains elusive. Here, as a proof of concept, we aimed to take advantage of an original coevolution method recently developed to shed light on the HCV fusion mechanism. When first applied to the well-characterized Dengue Virus (DENV) envelope glycoproteins, coevolution analysis was able to predict important structural features and rearrangements of these viral protein complexes. When applied to HCV E1E2, computational coevolution analysis predicted that E1 and E2 refold interdependently during fusion through rearrangements of the E2 Back Layer (BL). Consistently, a soluble BL-derived polypeptide inhibited HCV infection of hepatoma cell lines, primary human hepatocytes and humanized liver mice. We showed that this polypeptide specifically inhibited HCV fusogenic rearrangements, hence supporting the critical role of this domain during HCV fusion. By combining coevolution analysis and in vitro assays, we also uncovered functionally-significant coevolving signals between E1 and E2 BL/Stem regions that govern HCV fusion, demonstrating the accuracy of our coevolution predictions. Altogether, our work shed light on important structural features of the HCV fusion mechanism and contributes to advance our functional understanding of this process. This study also provides an important proof of concept that coevolution can be employed to explore viral protein mediated-processes, and can guide the development of innovative translational strategies against challenging human-tropic viruses. Several virus-mediated molecular processes remain poorly described, which dampen the development of potent anti-viral therapies. Hence, new experimental strategies need to be undertaken to improve and accelerate our understanding of these processes. Here, as a proof of concept, we employ amino-acid coevolution as a tool to gain insights into the structural rearrangements of Hepatitis C Virus (HCV) envelope glycoproteins E1 and E2 during virus fusion with the cell membrane, and provide a basis for the inhibition of this process. Our coevolution analysis predicted that a specific domain of E2, the Back Layer (BL) is involved into significant conformational changes with E1 during the fusion of the HCV membrane with the cellular membrane. Consistently, a recombinant, soluble form of the BL was able to inhibit E1E2 fusogenic rearrangements and HCV infection. Moreover, predicted coevolution networks involving E1 and BL residues, as well as E1 and BL-adjacent residues, were found to modulate virus fusion. Our data shows that coevolution analysis is a powerful and underused approach that can provide significant insights into the functions and structural rearrangements of viral proteins. Importantly, this approach can also provide structural and molecular basis for the design of effective anti-viral drugs, and opens new perspectives to rapidly identify effective antiviral strategies against emerging and re-emerging viral pathogens.
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Affiliation(s)
- Florian Douam
- CIRI–International Center for Infectiology Research, Team EVIR, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Univ Lyon, Lyon, France
- CNRS UMR5557 Microbial ecology, Université Claude Bernard Lyon 1, INRA, UMR1418, Villeurbanne, France
- Department of Molecular Biology, Princeton University, Princeton NJ, United States of America
| | - Floriane Fusil
- CIRI–International Center for Infectiology Research, Team EVIR, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Univ Lyon, Lyon, France
| | - Margot Enguehard
- CNRS UMR5557 Microbial ecology, Université Claude Bernard Lyon 1, INRA, UMR1418, Villeurbanne, France
- University of Lyon, Université Claude Bernard Lyon1, INRA, EPHE, IVPC, Viral Infections and Comparative Pathology, UMR754, Lyon, France
- Institut Hospitalo-Universitaire, Pôle Hépato-digestif, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Linda Dib
- Molecular Phylogenetics and Speciation, Département d’écologie et évolution, Université de Lausanne, Lausanne, Suisse
| | - Francesca Nadalin
- Sorbonne Université, CNRS, IBPS, UMR 7238, Laboratoire de Biologie Computationnelle et Quantitative, Paris, France
| | - Loïc Schwaller
- Mathematical Institute, Leiden University, Leiden, The Netherlands
| | - Gabriela Hrebikova
- Department of Molecular Biology, Princeton University, Princeton NJ, United States of America
| | - Jimmy Mancip
- CIRI–International Center for Infectiology Research, Team EVIR, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Univ Lyon, Lyon, France
| | - Laurent Mailly
- Inserm, U1110, Institut de Recherche sur les Maladies Virales et Hépatiques, Strasbourg, France
- Université de Strasbourg, Strasbourg, France
| | - Roland Montserret
- Institut de Biologie et Chimie des Protéines, Bases Moléculaires et Structurales des Systèmes Infectieux, Labex Ecofect, UMR 5086 CNRS, Université de Lyon, Lyon, France
| | - Qiang Ding
- Department of Molecular Biology, Princeton University, Princeton NJ, United States of America
| | - Carine Maisse
- University of Lyon, Université Claude Bernard Lyon1, INRA, EPHE, IVPC, Viral Infections and Comparative Pathology, UMR754, Lyon, France
| | - Emilie Carlot
- CAS Key Laboratory of Molecular Virology and Immunology, Unit of interspecies transmission of arboviruses and antivirals, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Ke Xu
- CAS Key Laboratory of Molecular Virology and Immunology, Unit of interspecies transmission of arboviruses and antivirals, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Els Verhoeyen
- CIRI–International Center for Infectiology Research, Team EVIR, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Univ Lyon, Lyon, France
| | - Thomas F. Baumert
- Institut Hospitalo-Universitaire, Pôle Hépato-digestif, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
- Inserm, U1110, Institut de Recherche sur les Maladies Virales et Hépatiques, Strasbourg, France
- Université de Strasbourg, Strasbourg, France
| | - Alexander Ploss
- Department of Molecular Biology, Princeton University, Princeton NJ, United States of America
| | - Alessandra Carbone
- Sorbonne Université, CNRS, IBPS, UMR 7238, Laboratoire de Biologie Computationnelle et Quantitative, Paris, France
- Institut Universitaire de France, Paris, France
- * E-mail: (FLC); (AC); (DL)
| | - François-Loïc Cosset
- CIRI–International Center for Infectiology Research, Team EVIR, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Univ Lyon, Lyon, France
- * E-mail: (FLC); (AC); (DL)
| | - Dimitri Lavillette
- CIRI–International Center for Infectiology Research, Team EVIR, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, Univ Lyon, Lyon, France
- CNRS UMR5557 Microbial ecology, Université Claude Bernard Lyon 1, INRA, UMR1418, Villeurbanne, France
- University of Lyon, Université Claude Bernard Lyon1, INRA, EPHE, IVPC, Viral Infections and Comparative Pathology, UMR754, Lyon, France
- CAS Key Laboratory of Molecular Virology and Immunology, Unit of interspecies transmission of arboviruses and antivirals, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- * E-mail: (FLC); (AC); (DL)
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16
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Fusogenic properties of the Ectodomain of HCV E2 envelope protein. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:728-736. [DOI: 10.1016/j.bbamem.2017.12.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 12/05/2017] [Accepted: 12/18/2017] [Indexed: 01/04/2023]
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17
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Functional Analysis of Hepatitis C Virus (HCV) Envelope Protein E1 Using a trans-Complementation System Reveals a Dual Role of a Putative Fusion Peptide of E1 in both HCV Entry and Morphogenesis. J Virol 2017; 91:JVI.02468-16. [PMID: 28100619 DOI: 10.1128/jvi.02468-16] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Accepted: 01/12/2017] [Indexed: 02/07/2023] Open
Abstract
Hepatitis C virus (HCV) is an enveloped RNA virus belonging to the Flaviviridae family. It infects mainly human hepatocytes and causes chronic liver diseases, including cirrhosis and cancer. HCV encodes two envelope proteins, E1 and E2, that form a heterodimer and mediate virus entry. While E2 has been extensively studied, less has been done so for E1, and its role in the HCV life cycle still needs to be elucidated. Here we developed a new cell culture model for HCV infection based on the trans-complementation of E1. Virus production of the HCV genome lacking the E1-encoding sequence can be efficiently rescued by the ectopic expression of E1 in trans The resulting virus, designated HCVΔE1, can propagate in packaging cells expressing E1 but results in only single-cycle infection in naive cells. By using the HCVΔE1 system, we explored the role of a putative fusion peptide (FP) of E1 in HCV infection. Interestingly, we found that the FP not only contributes to HCV entry, as previously reported, but also may be involved in virus morphogenesis. Finally, we identified amino acid residues in FP that are critical for biological functions of E1. In summary, our work not only provides a new cell culture model for studying HCV but also provides some insights into understanding the role of E1 in the HCV life cycle.IMPORTANCE Hepatitis C virus (HCV), an enveloped RNA virus, encodes two envelope proteins, E1 and E2, that form a heterodimeric complex to mediate virus entry. Compared to E2, the biological functions of E1 in the virus life cycle are not adequately investigated. Here we developed a new cell culture model for single-cycle HCV infection based on the trans-complementation of E1. The HCV genome lacking the E1-encoding sequence can be efficiently rescued for virus production by the ectopic expression of E1 in trans This new model renders a unique system to dissect functional domains and motifs in E1. Using this system, we found that a putative fusion peptide in E1 is a multifunctional structural element contributing to both HCV entry and morphogenesis. Our work has provided a new cell culture model to study HCV and provides insights into understanding the biological roles of E1 in the HCV life cycle.
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18
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Freedman H, Logan MR, Law JLM, Houghton M. Structure and Function of the Hepatitis C Virus Envelope Glycoproteins E1 and E2: Antiviral and Vaccine Targets. ACS Infect Dis 2016; 2:749-762. [PMID: 27933781 DOI: 10.1021/acsinfecdis.6b00110] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The hepatitis C virus (HCV) envelope glycoproteins E1 and E2 are critical in viral attachment and cell fusion, and studies of these proteins may provide valuable insights into their potential uses in vaccines and antiviral strategies. Progress has included elucidating the crystal structures of portions of their ectodomains, as well as many other studies of hypervariable regions, stem regions, glycosylation sites, and the participation of E1/E2 in viral fusion with the endosomal membrane. The available structural data have shed light on the binding sites of cross-neutralizing antibodies. A large amount of information has been discovered concerning heterodimerization, including the roles of transmembrane domains, disulfide bonding, and heptad repeat regions. The possible organization of higher order oligomers within the HCV virion has also been evaluated on the basis of experimental data. In this review, E1/E2 structure and function is discussed, and some important issues requiring further study are highlighted.
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Affiliation(s)
- Holly Freedman
- Li Ka Shing Institute of Virology, Department of Medical Microbiology
and Immunology, University of Alberta, Edmonton, Alberta, Canada
| | - Michael R. Logan
- Li Ka Shing Institute of Virology, Department of Medical Microbiology
and Immunology, University of Alberta, Edmonton, Alberta, Canada
| | - John Lok Man Law
- Li Ka Shing Institute of Virology, Department of Medical Microbiology
and Immunology, University of Alberta, Edmonton, Alberta, Canada
| | - Michael Houghton
- Li Ka Shing Institute of Virology, Department of Medical Microbiology
and Immunology, University of Alberta, Edmonton, Alberta, Canada
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19
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Alteration of a Second Putative Fusion Peptide of Structural Glycoprotein E2 of Classical Swine Fever Virus Alters Virus Replication and Virulence in Swine. J Virol 2016; 90:10299-10308. [PMID: 27605674 DOI: 10.1128/jvi.01530-16] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 08/29/2016] [Indexed: 12/13/2022] Open
Abstract
E2, the major envelope glycoprotein of classical swine fever virus (CSFV), is involved in several critical virus functions, including cell attachment, host range susceptibility, and virulence in natural hosts. Functional structural analysis of E2 based on a Wimley-White interfacial hydrophobicity distribution predicted the involvement of a loop (residues 864 to 881) stabilized by a disulfide bond (869CKWGGNWTCV878, named FPII) in establishing interactions with the host cell membrane. This loop further contains an 872GG873 dipeptide, as well as two aromatic residues (871W and 875W) accessible to solvent. Reverse genetics utilizing a full-length infectious clone of the highly virulent CSFV strain Brescia (BICv) was used to evaluate how amino acid substitutions within FPII may affect replication of BICv in vitro and virus virulence in swine. Recombinant CSFVs containing mutations in different residues of FPII were constructed. A particular construct, harboring amino acid substitutions W871T, W875D, and V878T (FPII.2), demonstrated a significantly decreased ability to replicate in a swine cell line (SK6) and swine macrophage primary cell cultures. Interestingly, mutated virus FPII.2 was completely attenuated in pigs. Also, animals infected with FPII.2 virus were protected against virulent challenge with Brescia virus at 21 days postvaccination. Supporting a role for the E2 the loop from residues 864 to 881 in membrane fusion, only synthetic peptides that were based on the native E2 functional sequence were competent for insertion into model membranes and perturbation of their integrity, and this functionality was lost in synthetic peptides harboring amino acid substitutions W871T, W875D, and V878T in FPII.2. IMPORTANCE This report describes the identification and characterization of a putative fusion peptide (FP) in the major structural protein E2 of classical swine fever virus (CSFV). The FP identification was performed by functional structural analysis of E2. We characterized the functional significance of this FP by using artificial membranes. Replacement of critical amino acid residues within the FP radically alters how it interacts with the artificial membranes. When we introduced the same mutations into the viral sequence, there was a reduction in replication in cell cultures, and when we infected domestic swine, the natural host of CSFV host, we observed that the virus was now completely attenuated in swine. In addition, the virus mutant that was attenuated in vivo efficiently protected pigs against wild-type virus. These results provide the proof of principle to support as a strategy for vaccine development the discovery and manipulation of FPs.
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Beer M, Wernike K, Dräger C, Höper D, Pohlmann A, Bergermann C, Schröder C, Klinkhammer S, Blome S, Hoffmann B. High Prevalence of Highly Variable Atypical Porcine Pestiviruses Found in Germany. Transbound Emerg Dis 2016; 64:e22-e26. [PMID: 27297961 DOI: 10.1111/tbed.12532] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Indexed: 11/29/2022]
Abstract
Recently, a novel atypical porcine pestivirus (APPV) with significant distribution was described in the USA. Subsequent screening of the German pig sector showed a high prevalence of APPV with high variability among strains. First indication of a cell culture isolate is provided which will allow further investigations like pathogenesis studies.
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Affiliation(s)
- M Beer
- Friedrich-Loeffler-Institut, Greifswald - Insel Riems, Germany
| | - K Wernike
- Friedrich-Loeffler-Institut, Greifswald - Insel Riems, Germany
| | - C Dräger
- Friedrich-Loeffler-Institut, Greifswald - Insel Riems, Germany
| | - D Höper
- Friedrich-Loeffler-Institut, Greifswald - Insel Riems, Germany
| | - A Pohlmann
- Friedrich-Loeffler-Institut, Greifswald - Insel Riems, Germany
| | - C Bergermann
- State Office for Agriculture Food Safety and Fishery Mecklenburg-Western Pomerania, Rostock, Germany
| | - C Schröder
- Friedrich-Loeffler-Institut, Greifswald - Insel Riems, Germany
| | | | - S Blome
- Friedrich-Loeffler-Institut, Greifswald - Insel Riems, Germany
| | - B Hoffmann
- Friedrich-Loeffler-Institut, Greifswald - Insel Riems, Germany
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21
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Lombana L, Ortega-Atienza S, Gómez-Gutiérrez J, Yélamos B, Peterson DL, Gavilanes F. The deletion of residues 268-292 of E1 impairs the ability of HCV envelope proteins to induce pore formation. Virus Res 2016; 217:63-70. [PMID: 26945847 DOI: 10.1016/j.virusres.2016.02.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 02/05/2016] [Accepted: 02/08/2016] [Indexed: 12/25/2022]
Abstract
We have obtained a chimeric protein containing the ectodomains of hepatitis C virus (HCV) envelope proteins but lacking the region 268-292 of E1. All its structural properties are coincident with those of the corresponding full length chimera. The deleted and entire chimeras were compared in terms of their membrane destabilizing properties. No differences were found in their ability to induce vesicle aggregation and lipid mixing but the deleted chimera showed a reduced capacity to promote leakage. The role of the deletion was also studied by obtaining HCV pseudoparticles (HCVpp). Both E1 and E2, and also the E1 deleted mutant, were incorporated into HCVpp to a similar level. However, HCVpp containing the E1 deleted protein are almost unable to infect Huh7 cells. These results point to the involvement of the region 268-292 in the formation of pores in the membrane necessary for the complete fusion of the membranes.
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Affiliation(s)
- Laura Lombana
- Department of Biochemistry and Molecular Biology, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Sara Ortega-Atienza
- Department of Biochemistry and Molecular Biology, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Julián Gómez-Gutiérrez
- Department of Biochemistry and Molecular Biology, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Belén Yélamos
- Department of Biochemistry and Molecular Biology, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Darrell L Peterson
- Department of Biochemistry and Molecular Biology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Francisco Gavilanes
- Department of Biochemistry and Molecular Biology, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain.
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22
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Alves NS, Mendes YS, Souza TLF, Bianconi ML, Silva JL, Gomes AMO, Oliveira AC. A biophysical characterization of the interaction of a hepatitis C virus membranotropic peptide with micelles. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2016; 1864:359-71. [PMID: 26773352 DOI: 10.1016/j.bbapap.2016.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 01/02/2016] [Accepted: 01/05/2016] [Indexed: 10/22/2022]
Abstract
Membrane fusion is a highly regulated process that allows enveloped viruses to enter cells and replicate. Viral glycoproteins trigger membrane fusion by means of internal sequences known as fusion peptides. The hepatitis C virus (HCV) genome encodes the envelope glycoproteins E1 and E2, but their specific roles in the fusion step and the localization of the fusion peptide remain uncharacterized. Here, we studied the biophysics of the interactions between the glycoprotein E2 peptide HCV421-445 and four different micellar systems providing ionic, non-ionic and zwitterionic surfaces to investigate the importance of electrostatic interactions for peptide-membrane binding. Circular dichroism, fluorescence spectroscopy and calorimetry were used to characterize peptide-micelle interactions and structural changes. Fluorescence quenching showed that HCV421-445 interacts with SDS or CTAB ionic, n-OGP non-ionic and DPC zwitterionic micelles. The indole ring of Trp seems to anchor the peptide in micelles. Trp residues seem to be more deeply inserted in ionic and non-ionic micelles where peptide interactions are more stable than with DPC zwitterionic micelles. The interaction with zwitterionic micelles appears to occur at the surface. Both interaction types are exothermic because of peptide-micelle interactions and a gain of secondary structure in the helical conformation. HCV421-445 interacts with detergent monomers and micelles. Peptide-micelle interaction is pH-independent. HCV421-445 interacts with membranes, promoting aggregation and coalescence of vesicles with content leakage, suggesting that HCV421-445 may participate in membrane fusion. This structural characterization contributes to our understanding of the molecular process that promotes fusion, which is important in the further development of new antiviral therapies.
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Affiliation(s)
- N S Alves
- Programa de Biologia Estrutural, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil; Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil
| | - Y S Mendes
- Programa de Biologia Estrutural, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil; Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil
| | - T L F Souza
- Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil; Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil
| | - M L Bianconi
- Programa de Biologia Estrutural, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil
| | - J L Silva
- Programa de Biologia Estrutural, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil; Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil
| | - A M O Gomes
- Programa de Biologia Estrutural, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil; Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil.
| | - A C Oliveira
- Programa de Biologia Estrutural, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil; Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brazil.
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23
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Perin PM, Haid S, Brown RJ, Doerrbecker J, Schulze K, Zeilinger C, von Schaewen M, Heller B, Vercauteren K, Luxenburger E, Baktash YM, Vondran FW, Speerstra S, Awadh A, Mukhtarov F, Schang LM, Kirschning A, Müller R, Guzman CA, Kaderali L, Randall G, Meuleman P, Ploss A, Pietschmann T. Flunarizine prevents hepatitis C virus membrane fusion in a genotype-dependent manner by targeting the potential fusion peptide within E1. Hepatology 2016; 63:49-62. [PMID: 26248546 PMCID: PMC4688136 DOI: 10.1002/hep.28111] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 08/05/2015] [Indexed: 12/12/2022]
Abstract
UNLABELLED To explore mechanisms of hepatitis C viral (HCV) replication we screened a compound library including licensed drugs. Flunarizine, a diphenylmethylpiperazine used to treat migraine, inhibited HCV cell entry in vitro and in vivo in a genotype-dependent fashion. Analysis of mosaic viruses between susceptible and resistant strains revealed that E1 and E2 glycoproteins confer susceptibility to flunarizine. Time of addition experiments and single particle tracking of HCV demonstrated that flunarizine specifically prevents membrane fusion. Related phenothiazines and pimozide also inhibited HCV infection and preferentially targeted HCV genotype 2 viruses. However, phenothiazines and pimozide exhibited improved genotype coverage including the difficult to treat genotype 3. Flunarizine-resistant HCV carried mutations within the alleged fusion peptide and displayed cross-resistance to these compounds, indicating that these drugs have a common mode of action. CONCLUSION These observations reveal novel details about HCV membrane fusion; moreover, flunarizine and related compounds represent first-in-class HCV fusion inhibitors that merit consideration for repurposing as a cost-effective component of HCV combination therapies.
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Affiliation(s)
- Paula M. Perin
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research; a joint venture between the Medical School Hannover and the Helmholtz Centre for Infection ResearchHannoverGermany
| | - Sibylle Haid
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research; a joint venture between the Medical School Hannover and the Helmholtz Centre for Infection ResearchHannoverGermany
| | - Richard J.P. Brown
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research; a joint venture between the Medical School Hannover and the Helmholtz Centre for Infection ResearchHannoverGermany
| | - Juliane Doerrbecker
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research; a joint venture between the Medical School Hannover and the Helmholtz Centre for Infection ResearchHannoverGermany
| | - Kai Schulze
- Department of Vaccinology and Applied MicrobiologyHelmholtz Centre of Infection ResearchBraunschweigGermany
| | - Carsten Zeilinger
- Institute of Organic Chemistry and Center of Biomolecular Drug Research, Leibniz UniversitätHannoverGermany
| | | | - Brigitte Heller
- Department of Molecular BiologyPrinceton UniversityPrincetonNJ
| | | | - Eva Luxenburger
- Helmholtz Institute for Pharmaceutical Research SaarlandSaarbrückenGermany
| | | | - Florian W.R. Vondran
- ReMediES, Department of GeneralVisceral and Transplantation Surgery, Hannover Medical SchoolHannoverGermany,German Centre for Infection Research, Hannover‐BraunschweigGermany
| | - Sietkse Speerstra
- Department of BiochemistryUniversity of AlbertaEdmontonABCanada,Li Ka Shing Institute of Virology, University of AlbertaEdmontonABCanada
| | - Abdullah Awadh
- Li Ka Shing Institute of Virology, University of AlbertaEdmontonABCanada,Department of Medical Microbiology and ImmunologyUniversity of AlbertaEdmontonABCanada
| | - Furkat Mukhtarov
- Department of BiochemistryUniversity of AlbertaEdmontonABCanada,Li Ka Shing Institute of Virology, University of AlbertaEdmontonABCanada
| | - Luis M. Schang
- Department of BiochemistryUniversity of AlbertaEdmontonABCanada,Li Ka Shing Institute of Virology, University of AlbertaEdmontonABCanada,Department of Medical Microbiology and ImmunologyUniversity of AlbertaEdmontonABCanada
| | - Andreas Kirschning
- Institute of Organic Chemistry and Center of Biomolecular Drug Research, Leibniz UniversitätHannoverGermany
| | - Rolf Müller
- Helmholtz Institute for Pharmaceutical Research SaarlandSaarbrückenGermany
| | - Carlos A. Guzman
- Department of Vaccinology and Applied MicrobiologyHelmholtz Centre of Infection ResearchBraunschweigGermany
| | | | - Glenn Randall
- Department of MicrobiologyThe University of ChicagoChicagoIL
| | | | - Alexander Ploss
- Department of Molecular BiologyPrinceton UniversityPrincetonNJ
| | - Thomas Pietschmann
- Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research; a joint venture between the Medical School Hannover and the Helmholtz Centre for Infection ResearchHannoverGermany,German Centre for Infection Research, Hannover‐BraunschweigGermany
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24
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Structures and Functions of Pestivirus Glycoproteins: Not Simply Surface Matters. Viruses 2015; 7:3506-29. [PMID: 26131960 PMCID: PMC4517112 DOI: 10.3390/v7072783] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 06/11/2015] [Accepted: 06/18/2015] [Indexed: 12/21/2022] Open
Abstract
Pestiviruses, which include economically important animal pathogens such as bovine viral diarrhea virus and classical swine fever virus, possess three envelope glycoproteins, namely Erns, E1, and E2. This article discusses the structures and functions of these glycoproteins and their effects on viral pathogenicity in cells in culture and in animal hosts. E2 is the most important structural protein as it interacts with cell surface receptors that determine cell tropism and induces neutralizing antibody and cytotoxic T-lymphocyte responses. All three glycoproteins are involved in virus attachment and entry into target cells. E1-E2 heterodimers are essential for viral entry and infectivity. Erns is unique because it possesses intrinsic ribonuclease (RNase) activity that can inhibit the production of type I interferons and assist in the development of persistent infections. These glycoproteins are localized to the virion surface; however, variations in amino acids and antigenic structures, disulfide bond formation, glycosylation, and RNase activity can ultimately affect the virulence of pestiviruses in animals. Along with mutations that are driven by selection pressure, antigenic differences in glycoproteins influence the efficacy of vaccines and determine the appropriateness of the vaccines that are currently being used in the field.
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25
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Douam F, Ploss A. Proteomic approaches to analyzing hepatitis C virus biology. Proteomics 2015; 15:2051-65. [PMID: 25809442 PMCID: PMC4559851 DOI: 10.1002/pmic.201500009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 02/25/2015] [Accepted: 03/19/2015] [Indexed: 12/15/2022]
Abstract
Hepatitis C virus (HCV) is a major cause of liver disease worldwide. Acute infection often progresses to chronicity resulting frequently in fibrosis, cirrhosis, and in rare cases, in the development of hepatocellular carcinoma. Although HCV has proven to be an arduous object of research and has raised important technical challenges, several experimental models have been developed all over the last two decades in order to improve our understanding of the virus life cycle, pathogenesis and virus-host interactions. The recent development of direct acting-agents, leading to considerable progress in treatment of patients, represents the direct outcomes of these achievements. Proteomic approaches have been of critical help to shed light on several aspect of the HCV biology such as virion composition, viral replication, and virus assembly and to unveil diagnostic or prognostic markers of HCV-induced liver disease. Here, we review how proteomic approaches have led to improve our understanding of HCV life cycle and liver disease, thus highlighting the relevance of these approaches for studying the complex interactions between other challenging human viral pathogens and their host.
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Affiliation(s)
- Florian Douam
- Department of Molecular Biology, Princeton University, 110 Lewis Thomas Laboratory, Washington Road, Princeton, NJ 08544
| | - Alexander Ploss
- Department of Molecular Biology, Princeton University, 110 Lewis Thomas Laboratory, Washington Road, Princeton, NJ 08544
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26
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Abstract
The past decade has witnessed steady and rapid progress in HCV research, which has led to the recent breakthrough in therapies against this significant human pathogen. Yet a deeper understanding of the life cycle of the virus is required to develop more affordable treatments and to advance vaccine design. HCV entry presents both a challenge for scientific research and an opportunity for alternative intervention approaches, owning to its highly complex nature and the myriad of players involved. More than half a dozen cellular proteins are implicated in HCV entry; and a more definitive picture regarding the structures of the glycoproteins is emerging. A role of apolipoproteins in HCV entry has also been established. Still, major questions remain, and the answers to these, which we summarize in this review, will hopefully close the gaps in our understanding and complete the puzzle that is HCV entry.
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Affiliation(s)
- Sarah C Ogden
- Department of Biological Science, Florida State University, Tallahassee, FL 32306-4295, USA
| | - Hengli Tang
- Department of Biological Science, Florida State University, Tallahassee, FL 32306-4295, USA ; Institute of Health Sciences, Anhui University, Hefei, 230601, PR China
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27
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Kong L, Jackson KN, Wilson IA, Law M. Capitalizing on knowledge of hepatitis C virus neutralizing epitopes for rational vaccine design. Curr Opin Virol 2015; 11:148-57. [PMID: 25932568 PMCID: PMC4507806 DOI: 10.1016/j.coviro.2015.04.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 04/08/2015] [Indexed: 12/13/2022]
Abstract
Hepatitis C virus infects nearly 3% of the world's population and is often referred as a silent epidemic. It is a leading cause of liver cirrhosis and hepatocellular carcinoma in endemic countries. Although antiviral drugs are now available, they are not readily accessible to marginalized social groups and developing nations that are disproportionally impacted by HCV. To stop the HCV pandemic, a vaccine is needed. Recent advances in HCV research have provided new opportunities for studying HCV neutralizing antibodies and their subsequent use for rational vaccine design. It is now recognized that neutralizing antibodies to conserved antigenic sites of the virus can cross-neutralize diverse HCV genotypes and protect against infection in vivo. Structural characterization of the neutralizing epitopes has provided valuable information for design of candidate immunogens.
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Affiliation(s)
- Leopold Kong
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Kelli N Jackson
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Ian A Wilson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA; Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Mansun Law
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037, USA.
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28
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Nayak A, Pattabiraman N, Fadra N, Goldman R, Kosakovsky Pond SL, Mazumder R. Structure-function analysis of hepatitis C virus envelope glycoproteins E1 and E2. J Biomol Struct Dyn 2014; 33:1682-94. [PMID: 25245635 DOI: 10.1080/07391102.2014.967300] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Hepatitis C virus (HCV) is the leading cause of chronic liver disease in humans. The envelope proteins of HCV are potential candidates for vaccine development. The absence of three-dimensional (3D) structures for the functional domain of HCV envelope proteins [E1.E2] monomer complex has hindered overall understanding of the virus infection, and also structure-based drug design initiatives. In this study, we report a 3D model containing both E1 and E2 proteins of HCV using the recently published structure of the core domain of HCV E2 and the functional part of E1, and investigate immunogenic implications of the model. HCV [E1.E2] molecule is modeled by using aa205-319 of E1 to aa421-716 of E2. Published experimental data were used to further refine the [E1.E2] model. Based on the model, we predict 77 exposed residues and several antigenic sites within the [E1.E2] that could serve as vaccine epitopes. This study identifies eight peptides which have antigenic propensity and have two or more sequentially exposed amino acids and 12 singular sites are under negative selection pressure that can serve as vaccine or therapeutic targets. Our special interest is 285FLVGQLFTFSPRRHW299 which has five negatively selected sites (L286, V287, G288, T292, and G303) with three of them sequential and four amino acids exposed (F285, L286, T292, and R296). This peptide in the E1 protein maps to dengue envelope vaccine target identified previously by our group. Our model provides for the first time an overall view of both the HCV envelope proteins thereby allowing researchers explore structure-based drug design approaches.
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Affiliation(s)
- Aparajita Nayak
- a Department of Biochemistry and Molecular Medicine , George Washington University , Washington , DC 20037 , USA
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29
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Unexpected structure for the N-terminal domain of hepatitis C virus envelope glycoprotein E1. Nat Commun 2014; 5:4874. [PMID: 25224686 PMCID: PMC4175578 DOI: 10.1038/ncomms5874] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 07/31/2014] [Indexed: 12/21/2022] Open
Abstract
Hepatitis C virus (HCV) infection remains a major health problem worldwide. HCV entry into host cells and membrane fusion are achieved by two envelope glycoproteins, E1 and E2. We report here the 3.5-Å resolution crystal structure of the N-terminal domain of the HCV E1 ectodomain, which reveals a complex network of covalently linked intertwined homodimers that do not harbour the expected truncated class II fusion protein fold. Hepatitis C virus (HCV) gains entry into host cells via envelope glycoproteins E1 and E2. Here, El Omari et al. present the crystal structure of the N terminus of the E1 ectodomain of HCV and show that it adopts a different fold than predicted.
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30
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Unexpected structural features of the hepatitis C virus envelope protein 2 ectodomain. J Virol 2014; 88:10280-8. [PMID: 24991010 DOI: 10.1128/jvi.00874-14] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Hepatitis C virus (HCV), a member of the family Flaviviridae, is a leading cause of chronic liver disease and cancer. Recent advances in HCV therapeutics have resulted in improved cure rates, but an HCV vaccine is not available and is urgently needed to control the global pandemic. Vaccine development has been hampered by the lack of high-resolution structural information for the two HCV envelope glycoproteins, E1 and E2. Recently, Kong and coworkers (Science 342:1090-1094, 2013, doi:10.1126/science.1243876) and Khan and coworkers (Nature 509[7500]:381-384, 2014, doi:10.1038/nature13117) independently determined the structure of the HCV E2 ectodomain core with some unexpected and informative results. The HCV E2 ectodomain core features a globular architecture with antiparallel β-sheets forming a central β sandwich. The residues comprising the epitopes of several neutralizing and nonneutralizing human monoclonal antibodies were also determined, which is an essential step toward obtaining a fine map of the human humoral response to HCV. Also clarified were the regions of E2 that directly bind CD81, an important HCV cellular receptor. While it has been widely assumed that HCV E2 is a class II viral fusion protein (VFP), the newly determined structure suggests that the HCV E2 ectodomain shares structural and functional similarities only with domain III of class II VFPs. The new structural determinations suggest that the HCV glycoproteins use a different mechanism than that used by class II fusion proteins for cell fusion.
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31
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Abstract
Enveloped viruses infect host cells by a membrane fusion reaction that takes place at the cell surface or in intracellular compartments following virus uptake. Fusion is mediated by the membrane interactions and conformational changes of specialized virus envelope proteins termed membrane fusion proteins. This article discusses the structures and refolding reactions of specific fusion proteins and the methods for their study and highlights outstanding questions in the field.
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Affiliation(s)
- Margaret Kielian
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461;
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32
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Effect of specific amino acid substitutions in the putative fusion peptide of structural glycoprotein E2 on Classical Swine Fever Virus replication. Virology 2014; 456-457:121-30. [DOI: 10.1016/j.virol.2014.03.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 02/25/2014] [Accepted: 03/04/2014] [Indexed: 11/21/2022]
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33
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Apellániz B, Huarte N, Largo E, Nieva JL. The three lives of viral fusion peptides. Chem Phys Lipids 2014; 181:40-55. [PMID: 24704587 PMCID: PMC4061400 DOI: 10.1016/j.chemphyslip.2014.03.003] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 03/19/2014] [Accepted: 03/20/2014] [Indexed: 02/07/2023]
Abstract
The presence of a fusion peptide (FP) is a hallmark of viral fusion glycoproteins. Structure–function relationships underlying FP conservation remain greatly unknown. FPs establish interactions satisfying their folding within pre-fusion glycoproteins. Upon fusion activation FPs insert into and restructure target membranes. FPs can finally combine with transmembrane domains to form integral membrane bundles.
Fusion peptides comprise conserved hydrophobic domains absolutely required for the fusogenic activity of glycoproteins from divergent virus families. After 30 years of intensive research efforts, the structures and functions underlying their high degree of sequence conservation are not fully elucidated. The long-hydrophobic viral fusion peptide (VFP) sequences are structurally constrained to access three successive states after biogenesis. Firstly, the VFP sequence must fulfill the set of native interactions required for (meta) stable folding within the globular ectodomains of glycoprotein complexes. Secondly, at the onset of the fusion process, they get transferred into the target cell membrane and adopt specific conformations therein. According to commonly accepted mechanistic models, membrane-bound states of the VFP might promote the lipid bilayer remodeling required for virus-cell membrane merger. Finally, at least in some instances, several VFPs co-assemble with transmembrane anchors into membrane integral helical bundles, following a locking movement hypothetically coupled to fusion-pore expansion. Here we review different aspects of the three major states of the VFPs, including the functional assistance by other membrane-transferring glycoprotein regions, and discuss briefly their potential as targets for clinical intervention.
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Affiliation(s)
- Beatriz Apellániz
- Biophysics Unit (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain
| | - Nerea Huarte
- Biophysics Unit (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain
| | - Eneko Largo
- Biophysics Unit (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain
| | - José L Nieva
- Biophysics Unit (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain.
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34
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Incorporation of hepatitis C virus E1 and E2 glycoproteins: the keystones on a peculiar virion. Viruses 2014; 6:1149-87. [PMID: 24618856 PMCID: PMC3970144 DOI: 10.3390/v6031149] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 02/21/2014] [Accepted: 02/27/2014] [Indexed: 12/13/2022] Open
Abstract
Hepatitis C virus (HCV) encodes two envelope glycoproteins, E1 and E2. Their structure and mode of fusion remain unknown, and so does the virion architecture. The organization of the HCV envelope shell in particular is subject to discussion as it incorporates or associates with host-derived lipoproteins, to an extent that the biophysical properties of the virion resemble more very-low-density lipoproteins than of any virus known so far. The recent development of novel cell culture systems for HCV has provided new insights on the assembly of this atypical viral particle. Hence, the extensive E1E2 characterization accomplished for the last two decades in heterologous expression systems can now be brought into the context of a productive HCV infection. This review describes the biogenesis and maturation of HCV envelope glycoproteins, as well as the interplay between viral and host factors required for their incorporation in the viral envelope, in a way that allows efficient entry into target cells and evasion of the host immune response.
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35
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Wang J, Li Y, Modis Y. Structural models of the membrane anchors of envelope glycoproteins E1 and E2 from pestiviruses. Virology 2014; 454-455:93-101. [PMID: 24725935 PMCID: PMC3986810 DOI: 10.1016/j.virol.2014.02.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 02/02/2014] [Accepted: 02/11/2014] [Indexed: 12/18/2022]
Abstract
The membrane anchors of viral envelope proteins play essential roles in cell entry. Recent crystal structures of the ectodomain of envelope protein E2 from a pestivirus suggest that E2 belongs to a novel structural class of membrane fusion machinery. Based on geometric constraints from the E2 structures, we generated atomic models of the E1 and E2 membrane anchors using computational approaches. The E1 anchor contains two amphipathic perimembrane helices and one transmembrane helix; the E2 anchor contains a short helical hairpin stabilized in the membrane by an arginine residue, similar to flaviviruses. A pair of histidine residues in the E2 ectodomain may participate in pH sensing. The proposed atomic models point to Cys987 in E2 as the site of disulfide bond linkage with E1 to form E1-E2 heterodimers. The membrane anchor models provide structural constraints for the disulfide bonding pattern and overall backbone conformation of the E1 ectodomain.
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Affiliation(s)
- Jimin Wang
- Department of Molecular Biophysics and Biochemistry, Yale University, 266 Whitney Avenue, New Haven, CT 06520, USA.
| | - Yue Li
- Department of Molecular Biophysics and Biochemistry, Yale University, 266 Whitney Avenue, New Haven, CT 06520, USA
| | - Yorgo Modis
- Department of Molecular Biophysics and Biochemistry, Yale University, 266 Whitney Avenue, New Haven, CT 06520, USA.
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36
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A novel membrane fusion protein family in Flaviviridae? Trends Microbiol 2014; 22:176-82. [PMID: 24569295 PMCID: PMC3985287 DOI: 10.1016/j.tim.2014.01.008] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 01/23/2014] [Accepted: 01/27/2014] [Indexed: 11/24/2022]
Abstract
Enveloped viruses must fuse their lipid membrane to a cellular membrane to deliver their genome into the cytoplasm for replication. Viral envelope proteins catalyze this critical membrane fusion event. They fall into three distinct structural classes. In 2013, envelope proteins from a pestivirus and hepatitis C virus were found to have two distinct novel folds. This was unexpected because these viruses are in the same family as flaviviruses, which have class II fusion proteins. We propose that the membrane fusion machinery of the closely related pestiviruses and hepatitis C virus defines a new structural class. This and other recently identified structural relationships between viral fusion proteins shift the paradigm for how these proteins evolved.
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37
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Relating structure to evolution in class II viral membrane fusion proteins. Curr Opin Virol 2014; 5:34-41. [PMID: 24525225 PMCID: PMC4028412 DOI: 10.1016/j.coviro.2014.01.009] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 01/17/2014] [Indexed: 12/25/2022]
Abstract
Until 2013, class II proteins had only been found in flaviviruses and alphaviruses. A class II fusion protein was recently discovered in the unrelated phlebovirus genus. Within the same family as alphaviruses, rubella virus has a divergent class II fold. Pestiviruses, although they are Flaviviridae, have fusion proteins from a novel class. Viral class II proteins may originate from cellular class II fusion protein ancestors.
Enveloped viruses must fuse their lipid membrane to a cellular membrane to deliver the viral genome into the cytoplasm for replication. Viral envelope proteins catalyze this critical membrane fusion event. They fall into at least three distinct structural classes. Class II fusion proteins have a conserved three-domain architecture and are found in many important viral pathogens. Until 2013, class II proteins had only been found in flaviviruses and alphaviruses. However, in 2013 a class II fusion protein was discovered in the unrelated phlebovirus genus, and two unexpectedly divergent envelope proteins were identified in families that also contain prototypical class II proteins. The structural relationships of newly identified class II proteins, reviewed herein, shift the paradigm for how these proteins evolved.
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38
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Lindenbach BD, Rice CM. The ins and outs of hepatitis C virus entry and assembly. Nat Rev Microbiol 2013; 11:688-700. [PMID: 24018384 DOI: 10.1038/nrmicro3098] [Citation(s) in RCA: 275] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Hepatitis C virus, a major human pathogen, produces infectious virus particles with several unique features, such as an ability to interact with serum lipoproteins, a dizzyingly complicated process of virus entry, and a pathway of virus assembly and release that is closely linked to lipoprotein secretion. Here, we review these unique features, with an emphasis on recent discoveries concerning virus particle structure, virus entry and virus particle assembly and release.
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Affiliation(s)
- Brett D Lindenbach
- Department of Microbial Pathogenesis, Yale University, New Haven, Connecticut 06536, USA
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39
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Crystal structure of glycoprotein E2 from bovine viral diarrhea virus. Proc Natl Acad Sci U S A 2013; 110:6805-10. [PMID: 23569276 DOI: 10.1073/pnas.1300524110] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Pestiviruses, including bovine viral diarrhea virus, are important animal pathogens and are closely related to hepatitis C virus, which remains a major global health threat. They have an outer lipid envelope bearing two glycoproteins, E1 and E2, required for cell entry. They deliver their genome into the host cell cytoplasm by fusion of their envelope with a cellular membrane. The crystal structure of bovine viral diarrhea virus E2 reveals a unique protein architecture consisting of two Ig-like domains followed by an elongated β-stranded domain with a new fold. E2 forms end-to-end homodimers with a conserved C-terminal motif rich in aromatic residues at the contact. A disulfide bond across the interface explains the acid resistance of pestiviruses and their requirement for a redox activation step to initiate fusion. From the structure of E2, we propose alternative possible membrane fusion mechanisms. We expect the pestivirus fusion apparatus to be conserved in hepatitis C virus.
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40
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El Omari K, Iourin O, Harlos K, Grimes J, Stuart D. Structure of a pestivirus envelope glycoprotein E2 clarifies its role in cell entry. Cell Rep 2013; 3:30-5. [PMID: 23273918 PMCID: PMC3607223 DOI: 10.1016/j.celrep.2012.12.001] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 11/10/2012] [Accepted: 12/03/2012] [Indexed: 12/15/2022] Open
Abstract
Enveloped viruses have developed various adroit mechanisms to invade their host cells. This process requires one or more viral envelope glycoprotein to achieve cell attachment and membrane fusion. Members of the Flaviviridae such as flaviviruses possess only one envelope glycoprotein, E, whereas pestiviruses and hepacivirus encode two glycoproteins, E1 and E2. Although E2 is involved in cell attachment, it has been unclear which protein is responsible for membrane fusion. We report the crystal structures of the homodimeric glycoprotein E2 from the pestivirus bovine viral diarrhea virus 1 (BVDV1) at both neutral and low pH. Unexpectedly, BVDV1 E2 does not have a class II fusion protein fold, and at low pH the N-terminal domain is disordered, similarly to the intermediate postfusion state of E2 from sindbis virus, an alphavirus. Our results suggest that the pestivirus and possibly the hepacivirus fusion machinery are unlike any previously observed.
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Affiliation(s)
- Kamel El Omari
- Division of Structural Biology, The Wellcome Trust Center for Human Genetics, University of Oxford, Headington, Oxford OX3 7BN, UK
| | - Oleg Iourin
- Division of Structural Biology, The Wellcome Trust Center for Human Genetics, University of Oxford, Headington, Oxford OX3 7BN, UK
| | - Karl Harlos
- Division of Structural Biology, The Wellcome Trust Center for Human Genetics, University of Oxford, Headington, Oxford OX3 7BN, UK
| | - Jonathan M. Grimes
- Division of Structural Biology, The Wellcome Trust Center for Human Genetics, University of Oxford, Headington, Oxford OX3 7BN, UK
- Diamond Light Source Limited, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK
| | - David I. Stuart
- Division of Structural Biology, The Wellcome Trust Center for Human Genetics, University of Oxford, Headington, Oxford OX3 7BN, UK
- Diamond Light Source Limited, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK
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41
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Molecular biology of bovine viral diarrhea virus. Biologicals 2013; 41:2-7. [DOI: 10.1016/j.biologicals.2012.07.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Revised: 06/27/2012] [Accepted: 07/06/2012] [Indexed: 11/21/2022] Open
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42
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Iourin O, Harlos K, El Omari K, Lu W, Kadlec J, Iqbal M, Meier C, Palmer A, Jones I, Thomas C, Brownlie J, Grimes JM, Stuart DI. Expression, purification and crystallization of the ectodomain of the envelope glycoprotein E2 from Bovine viral diarrhoea virus. Acta Crystallogr Sect F Struct Biol Cryst Commun 2012; 69:35-8. [PMID: 23295482 DOI: 10.1107/s1744309112049184] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Accepted: 11/29/2012] [Indexed: 01/17/2023]
Abstract
Bovine viral diarrhoea virus (BVDV) is an economically important animal pathogen which is closely related to Hepatitis C virus. Of the structural proteins, the envelope glycoprotein E2 of BVDV is the major antigen which induces neutralizing antibodies; thus, BVDV E2 is considered as an ideal target for use in subunit vaccines. Here, the expression, purification of wild-type and mutant forms of the ectodomain of BVDV E2 and subsequent crystallization and data collection of two crystal forms grown at low and neutral pH are reported. Native and multiple-wavelength anomalous dispersion (MAD) data sets have been collected and structure determination is in progress.
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Affiliation(s)
- Oleg Iourin
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, England
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43
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Weng D, Qi H, Wu TT, Yan M, Sun R, Lu Y. Visible light powered self-disinfecting coatings for influenza viruses. NANOSCALE 2012; 4:2870-2874. [PMID: 22456700 DOI: 10.1039/c2nr30388d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Influenza A viruses, the pathogens responsible for the recent swine flu outbreak and many historical pandemics, remain a threat to the public health. We report herein the fabrication of self-disinfecting surfaces from photoactive building nanocrystals, which can inactivate influenza viruses rapidly, spontaneously and continuously under visible light illumination.
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Affiliation(s)
- Ding Weng
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, 420 Westwood Plaza, 5531 Boelter Hall, Los Angeles, CA 90095, USA
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44
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Helle F, Duverlie G, Dubuisson J. The hepatitis C virus glycan shield and evasion of the humoral immune response. Viruses 2011; 3:1909-32. [PMID: 22069522 PMCID: PMC3205388 DOI: 10.3390/v3101909] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Revised: 09/28/2011] [Accepted: 10/01/2011] [Indexed: 12/14/2022] Open
Abstract
Despite the induction of effective immune responses, 80% of hepatitis C virus (HCV)-infected individuals progress from acute to chronic hepatitis. In contrast to the cellular immune response, the role of the humoral immune response in HCV clearance is still subject to debate. Indeed, HCV escapes neutralizing antibodies in chronically infected patients and reinfection has been described in human and chimpanzee. Studies of antibody-mediated HCV neutralization have long been hampered by the lack of cell-culture-derived virus and the absence of a small animal model. However, the development of surrogate models and recent progress in HCV propagation in vitro now enable robust neutralization assays to be performed. These advances are beginning to shed some light on the mechanisms of HCV neutralization. This review summarizes the current state of knowledge of the viral targets of anti-HCV-neutralizing antibodies and the mechanisms that enable HCV to evade the humoral immune response. The recent description of the HCV glycan shield that reduces the immunogenicity of envelope proteins and masks conserved neutralizing epitopes at their surface constitutes the major focus of this review.
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Affiliation(s)
- François Helle
- Laboratory of Virology, EA4294, Jules Verne University of Picardie, Amiens 80000, France; E-Mail:
| | - Gilles Duverlie
- Laboratory of Virology, EA4294, Jules Verne University of Picardie, Amiens 80000, France; E-Mail:
- Virology Department, Amiens University Hospital Center, South Hospital, Amiens 80000, France
| | - Jean Dubuisson
- Inserm U1019, CNRS UMR8204, Center for Infection and Immunity of Lille (CIIL), Institut Pasteur de Lille, Université Lille Nord de France, Lille 59021, France; E-Mail:
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45
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Mazumdar B, Banerjee A, Meyer K, Ray R. Hepatitis C virus E1 envelope glycoprotein interacts with apolipoproteins in facilitating entry into hepatocytes. Hepatology 2011; 54:1149-56. [PMID: 21735466 PMCID: PMC3184191 DOI: 10.1002/hep.24523] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Accepted: 06/17/2011] [Indexed: 12/20/2022]
Abstract
UNLABELLED Our previous studies demonstrated that hepatitis C virus (HCV) envelope glycoproteins 1 and 2 (E1 and E2) display distinct reactivity to different cell-surface molecules. In this study, we characterized the interaction of E1 and E2 with apolipoproteins in facilitating virus entry. The results suggested a higher neutralization of vesicular stomatitis virus (VSV)/HCV E1-G pseudotype infectivity by antibodies to apolipoprotein E (ApoE) than apolipoprotein B (ApoB), with VSV/HCV E2-G pseudotype infectivity remaining largely unaffected. Neutralization of cell-culture-grown HCV infectivity by antiserum to ApoE and, to a lesser extent, by ApoB further verified their involvement in virus entry. HCV E1, but not E2, displayed binding with ApoE and ApoB by enzyme-linked immunosorbent assay. Binding of E1 with apolipoproteins were further supported by coimmunoprecipitation from human hepatocytes expressing E1. Rabbit antiserum to a selected E1 ectodomain-derived peptide displayed ∼ 50% neutralization of E1-G pseudotype infectivity. Furthermore, E1 ectodomain-derived synthetic peptides significantly inhibited the interaction of E1 with both the apolipoproteins. Investigation on the role of low-density lipoprotein receptor (LDL-R) as a hepatocyte surface receptor for virus entry suggested a significant reduction in E1-G pseudotype plaque numbers (∼ 70%) by inhibiting LDL-R ligand-binding activity using human proprotein convertase subtilisin/kexin type 9 and platelet factor-4, whereas they had a minimal inhibitory effect on the E2-G pseudotype. CONCLUSION Together, the results suggested an association between HCV E1 and apolipoproteins, which may facilitate virus entry through LDL-R into mammalian cells.
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Affiliation(s)
| | - Arup Banerjee
- Department of Internal Medicine, Saint Louis University, Missouri
| | - Keith Meyer
- Department of Internal Medicine, Saint Louis University, Missouri
| | - Ranjit Ray
- Department of Internal Medicine, Saint Louis University, Missouri
- Department of Molecular Microbiology and Immunology, Saint Louis University, Missouri
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46
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Abstract
A number of viruses transport their genomic material from cell to cell enclosed within a lipid bilayer that is in turn encased within a symmetric protein shell. This review focuses in a group of RNA viruses that have this type of virions. This group includes several of important human pathogenic viruses, such as the hepatitis C virus, dengue virus, chikungunya virus, rubella virus and the bunyaviruses. The best studied are the flaviviruses and the alphaviruses, which have a β-sheet rich class II viral fusion protein used for entry into susceptible cells. We extend here the class II concept to encompass symmetric viruses in which the envelope proteins are derived from a precursor polyprotein containing two transmembrane glycoproteins arranged in tandem. The first glycoprotein acts as chaperone for the folding of the second one, which carries the membrane fusion function. Since the bunyaviruses, included here, are very similar to the class I arenaviruses in other respects, this analysis highlights the patchwork nature of the various viral functional modules acting at different stages of the virus cycle, which appear assembled from genes of different origins.
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Affiliation(s)
- Marie-Christine Vaney
- Institut Pasteur, Département de Virologie, Unité de Virologie Structurale, F-75724 Paris Cedex 15, France
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47
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Khaliq S, Jahan S, Ijaz B, Ahmad W, Asad S, Hassan S. Inhibition of hepatitis C virus genotype 3a by siRNAs targeting envelope genes. Arch Virol 2010; 156:433-42. [PMID: 21161551 DOI: 10.1007/s00705-010-0887-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Accepted: 12/04/2010] [Indexed: 02/06/2023]
Abstract
Hepatitis C virus (HCV) genotype 3a is considered a significant risk factor for the development of liver diseases and hepatocellular carcinoma for most of the cases in Pakistan. Because of the limited efficiency of the current therapy, RNA interference (RNAi), which results in sequence-specific degradation of HCV RNA, has potential as a powerful alternative molecular therapeutic approach. The envelope genes (E1 and E2) of HCV come in immediate contact with cells during infection and therefore might be a relevant target for new drug development. In the present study, the expression of E1 and E2 genes of HCV genotype 3a was dramatically reduced at both the mRNA and protein level using gene-specific small interfering RNAs (siRNA) when compared to mock-transfected and cells treated with control siRNAs. The potential of siRNAs to inhibit HCV-3a replication in serum-infected Huh-7 cells was also demonstrated by combined treatment of siRNAs against the E1 and E2 genes, which resulted in a significant decrease in HCV viral copy number. This clearly demonstrates that the RNAi-mediated silencing of HCV E1 and E2 is among the first of its type for the development of an effective siRNA-based therapeutic option against HCV-3a.
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Affiliation(s)
- Saba Khaliq
- Applied and Functional Genomics Laboratory, National Centre of Excellence in Molecular Biology, University of Punjab, Lahore 53700, Pakistan
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48
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Tencate V, Sainz B, Cotler SJ, Uprichard SL. Potential treatment options and future research to increase hepatitis C virus treatment response rate. Hepat Med 2010; 2010:125-145. [PMID: 21331152 PMCID: PMC3039485 DOI: 10.2147/hmer.s7193] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Hepatitis C virus (HCV) is a liver-tropic blood-borne pathogen that affects more than 170 million people worldwide. Although acute infections are usually asymptomatic, up to 90% of HCV infections persist with the possibility of long-term consequences such as liver fibrosis, cirrhosis, steatosis, insulin resistance, or hepatocellular carcinoma. As such, HCV-associated liver disease is a major public health concern. Although the currently available standard of care therapy of pegylated interferon α plus ribavirin successfully treats infection in a subset of patients, the development of more effective, less toxic HCV antivirals is a health care imperative. This review not only discusses the limitations of the current HCV standard of care but also evaluates upcoming HCV treatment options and how current research elucidating the viral life cycle is facilitating the development of HCV-specific therapeutics that promise to greatly improve treatment response rates both before and after liver transplantation.
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Affiliation(s)
- Veronica Tencate
- Department of Medicine, Section of Hepatology, University of Illinois at Chicago, Chicago, IL, USA
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49
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Baldick CJ, Wichroski MJ, Pendri A, Walsh AW, Fang J, Mazzucco CE, Pokornowski KA, Rose RE, Eggers BJ, Hsu M, Zhai W, Zhai G, Gerritz SW, Poss MA, Meanwell NA, Cockett MI, Tenney DJ. A novel small molecule inhibitor of hepatitis C virus entry. PLoS Pathog 2010; 6:e1001086. [PMID: 20838466 PMCID: PMC2936744 DOI: 10.1371/journal.ppat.1001086] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2010] [Accepted: 08/03/2010] [Indexed: 12/25/2022] Open
Abstract
Small molecule inhibitors of hepatitis C virus (HCV) are being developed to complement or replace treatments with pegylated interferons and ribavirin, which have poor response rates and significant side effects. Resistance to these inhibitors emerges rapidly in the clinic, suggesting that successful therapy will involve combination therapy with multiple inhibitors of different targets. The entry process of HCV into hepatocytes represents another series of potential targets for therapeutic intervention, involving viral structural proteins that have not been extensively explored due to experimental limitations. To discover HCV entry inhibitors, we utilized HCV pseudoparticles (HCVpp) incorporating E1-E2 envelope proteins from a genotype 1b clinical isolate. Screening of a small molecule library identified a potent HCV-specific triazine inhibitor, EI-1. A series of HCVpp with E1-E2 sequences from various HCV isolates was used to show activity against all genotype 1a and 1b HCVpp tested, with median EC50 values of 0.134 and 0.027 µM, respectively. Time-of-addition experiments demonstrated a block in HCVpp entry, downstream of initial attachment to the cell surface, and prior to or concomitant with bafilomycin inhibition of endosomal acidification. EI-1 was equally active against cell-culture adapted HCV (HCVcc), blocking both cell-free entry and cell-to-cell transmission of virus. HCVcc with high-level resistance to EI-1 was selected by sequential passage in the presence of inhibitor, and resistance was shown to be conferred by changes to residue 719 in the carboxy-terminal transmembrane anchor region of E2, implicating this envelope protein in EI-1 susceptibility. Combinations of EI-1 with interferon, or inhibitors of NS3 or NS5A, resulted in additive to synergistic activity. These results suggest that inhibitors of HCV entry could be added to replication inhibitors and interferons already in development.
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Affiliation(s)
- Carl J Baldick
- Bristol-Myers Squibb, Research and Development, Wallingford, Connecticut, United States of America.
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50
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Uprichard SL. Hepatitis C virus experimental model systems and antiviral drug research. Virol Sin 2010; 25:227-45. [PMID: 20960298 DOI: 10.1007/s12250-010-3134-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2010] [Accepted: 04/18/2010] [Indexed: 12/27/2022] Open
Abstract
An estimated 130 million people worldwide are chronically infected with hepatitis C virus (HCV) making it a leading cause of liver disease worldwide. Because the currently available therapy of pegylated interferon-alpha and ribavirin is only effective in a subset of patients, the development of new HCV antivirals is a healthcare imperative. This review discusses the experimental models available for HCV antiviral drug research, recent advances in HCV antiviral drug development, as well as active research being pursued to facilitate development of new HCV-specific therapeutics.
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Affiliation(s)
- Susan L Uprichard
- Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA.
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