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Pierce BG, Felbinger N, Metcalf M, Toth EA, Ofek G, Fuerst TR. Hepatitis C Virus E1E2 Structure, Diversity, and Implications for Vaccine Development. Viruses 2024; 16:803. [PMID: 38793684 PMCID: PMC11125608 DOI: 10.3390/v16050803] [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: 03/21/2024] [Revised: 05/02/2024] [Accepted: 05/15/2024] [Indexed: 05/26/2024] Open
Abstract
Hepatitis C virus (HCV) is a major medical health burden and the leading cause of chronic liver disease and cancer worldwide. More than 58 million people are chronically infected with HCV, with 1.5 million new infections occurring each year. An effective HCV vaccine is a major public health and medical need as recognized by the World Health Organization. However, due to the high variability of the virus and its ability to escape the immune response, HCV rapidly accumulates mutations, making vaccine development a formidable challenge. An effective vaccine must elicit broadly neutralizing antibodies (bnAbs) in a consistent fashion. After decades of studies from basic research through clinical development, the antigen of choice is considered the E1E2 envelope glycoprotein due to conserved, broadly neutralizing antigenic domains located in the constituent subunits of E1, E2, and the E1E2 heterodimeric complex itself. The challenge has been elicitation of robust humoral and cellular responses leading to broad virus neutralization due to the relatively low immunogenicity of this antigen. In view of this challenge, structure-based vaccine design approaches to stabilize key antigenic domains have been hampered due to the lack of E1E2 atomic-level resolution structures to guide them. Another challenge has been the development of a delivery platform in which a multivalent form of the antigen can be presented in order to elicit a more robust anti-HCV immune response. Recent nanoparticle vaccines are gaining prominence in the field due to their ability to facilitate a controlled multivalent presentation and trafficking to lymph nodes, where they can interact with both the cellular and humoral components of the immune system. This review focuses on recent advances in understanding the E1E2 heterodimeric structure to facilitate a rational design approach and the potential for development of a multivalent nanoparticle-based HCV E1E2 vaccine. Both aspects are considered important in the development of an effective HCV vaccine that can effectively address viral diversity and escape.
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Affiliation(s)
- Brian G. Pierce
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA; (B.G.P.); (N.F.); (M.M.); (E.A.T.); (G.O.)
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Nathaniel Felbinger
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA; (B.G.P.); (N.F.); (M.M.); (E.A.T.); (G.O.)
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Matthew Metcalf
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA; (B.G.P.); (N.F.); (M.M.); (E.A.T.); (G.O.)
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Eric A. Toth
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA; (B.G.P.); (N.F.); (M.M.); (E.A.T.); (G.O.)
| | - Gilad Ofek
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA; (B.G.P.); (N.F.); (M.M.); (E.A.T.); (G.O.)
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Thomas R. Fuerst
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA; (B.G.P.); (N.F.); (M.M.); (E.A.T.); (G.O.)
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
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Korenkov M, Zehner M, Cohen-Dvashi H, Borenstein-Katz A, Kottege L, Janicki H, Vanshylla K, Weber T, Gruell H, Koch M, Diskin R, Kreer C, Klein F. Somatic hypermutation introduces bystander mutations that prepare SARS-CoV-2 antibodies for emerging variants. Immunity 2023; 56:2803-2815.e6. [PMID: 38035879 DOI: 10.1016/j.immuni.2023.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 07/19/2023] [Accepted: 11/06/2023] [Indexed: 12/02/2023]
Abstract
Somatic hypermutation (SHM) drives affinity maturation and continues over months in SARS-CoV-2-neutralizing antibodies (nAbs). However, several potent SARS-CoV-2 antibodies carry no or only a few mutations, leaving the question of how ongoing SHM affects neutralization unclear. Here, we reverted variable region mutations of 92 antibodies and tested their impact on SARS-CoV-2 binding and neutralization. Reverting higher numbers of mutations correlated with decreasing antibody functionality. However, for some antibodies, including antibodies of the public clonotype VH1-58, neutralization of Wu01 remained unaffected. Although mutations were dispensable for Wu01-induced VH1-58 antibodies to neutralize Alpha, Beta, and Delta variants, they were critical for Omicron BA.1/BA.2 neutralization. We exploited this knowledge to convert the clinical antibody tixagevimab into a BA.1/BA.2 neutralizer. These findings broaden our understanding of SHM as a mechanism that not only improves antibody responses during affinity maturation but also contributes to antibody diversification, thus increasing the chances of neutralizing viral escape variants.
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Affiliation(s)
- Michael Korenkov
- Laboratory of Experimental Immunology, Institute of Virology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany
| | - Matthias Zehner
- Laboratory of Experimental Immunology, Institute of Virology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany
| | - Hadas Cohen-Dvashi
- Department of Chemical and Structural Biology, Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Aliza Borenstein-Katz
- Department of Chemical and Structural Biology, Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Lisa Kottege
- Laboratory of Experimental Immunology, Institute of Virology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany
| | - Hanna Janicki
- Laboratory of Experimental Immunology, Institute of Virology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany
| | - Kanika Vanshylla
- Laboratory of Experimental Immunology, Institute of Virology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany
| | - Timm Weber
- Laboratory of Experimental Immunology, Institute of Virology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany
| | - Henning Gruell
- Laboratory of Experimental Immunology, Institute of Virology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany
| | - Manuel Koch
- Institute for Dental Research and Oral Musculoskeletal Biology and Center for Biochemistry, University of Cologne, 50931 Cologne, Germany
| | - Ron Diskin
- Department of Chemical and Structural Biology, Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Christoph Kreer
- Laboratory of Experimental Immunology, Institute of Virology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany.
| | - Florian Klein
- Laboratory of Experimental Immunology, Institute of Virology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931 Cologne, Germany; German Center for Infection Research, Partner Site Bonn-Cologne, 50931 Cologne, Germany; Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany.
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3
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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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Czarnota A, Offersgaard A, Owsianka A, Alzua GP, Bukh J, Gottwein JM, Patel AH, Bieńkowska-Szewczyk K, Grzyb K. Effect of Glycan Shift on Antibodies against Hepatitis C Virus E2 412-425 Epitope Elicited by Chimeric sHBsAg-Based Virus-Like Particles. Microbiol Spectr 2023; 11:e0254622. [PMID: 36719195 PMCID: PMC10100762 DOI: 10.1128/spectrum.02546-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 01/12/2023] [Indexed: 02/01/2023] Open
Abstract
Two of the most important mechanisms of hepatitis C virus (HCV) immune evasion are the high variability of the amino acid sequence and epitope shielding via heavy glycosylation of the envelope (E) proteins. Previously, we showed that chimeric sHBsAg (hepatitis B virus [HBV] small surface antigen)-based virus-like particles (VLPs) carrying highly conserved epitope I from the HCV E2 glycoprotein (sHBsAg_412-425) elicit broadly neutralizing antibodies (bnAbs). However, many reports have identified escape mutations for such bnAbs that shift the N-glycosylation site from N417 to N415. This shift effectively masks the recognition of epitope I by antibodies raised against the wild-type glycoprotein. To investigate if glycan-shift-mediated immune evasion could be overcome by targeted vaccination strategies, we designed sHBsAg-based VLPs carrying epitope I with an N417S change (sHBsAg_N417S). Studies in BALB/c mice revealed that both sHBsAg_412-425 and sHBsAg_N417S VLPs were immunogenic, eliciting antibodies that recognized peptides encompassing epitope I regardless of the N417S change. However, we observed substantial differences in E1E2 glycoprotein binding and cell culture-derived HCV (HCVcc) neutralization between the sera elicited by sHBsAg_412-425 and those elicited by sHBsAg_N417S VLPs. Our results suggest a complex interplay among antibodies targeting epitope I, the E1E2 glycosylation status, and the epitope or global E1E2 conformation. Additionally, we observed striking similarities in the E1E2 glycoprotein binding patterns and HCVcc neutralization between sHBsAg_412-425 sera and AP33, suggesting that the immunization of mice with sHBsAg_412-425 VLPs can elicit AP33-like antibodies. This study emphasizes the role of antibodies against epitope I and represents an initial effort toward designing an antigen that elicits an immune response against epitope I with a glycan shift change. IMPORTANCE Epitope I, located within amino acids 412 to 423 of the HCV E2 glycoprotein, is an important target for an epitope-based HCV vaccine. One interesting feature of epitope I is the N417 glycosylation site, where a single change to S417 or T417 can shift the glycosylation site to position N415. This shift can effectively prevent the binding of broadly neutralizing antibodies targeting epitope I. Aiming to overcome glycan-shift-mediated immune evasion, we constructed sHBsAg_N417S VLPs carrying E2 epitope I, with N417S, and compared them with VLPs carrying wild-type epitope I. We show that antibodies elicited by the sHBsAg-based VLPs presenting two variants of the 412-425 epitope targeted two distinct glycan variants of the HCV E1E2 heterodimer. Our study suggests that due to the conformational flexibility of the E2 glycoprotein and epitope I, future vaccine antigens should elicit antibodies targeting more than one conformation and glycosylation variant of the 412-423 epitope.
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Affiliation(s)
- Anna Czarnota
- Laboratory of Virus Molecular Biology, Intercollegiate Faculty of Biotechnology of the University of Gdańsk and Medical University of Gdańsk, Gdańsk, Poland
| | - Anna Offersgaard
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Copenhagen University Hospital—Hvidovre, Hvidovre, Denmark
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ania Owsianka
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Garazi Peña Alzua
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Copenhagen University Hospital—Hvidovre, Hvidovre, Denmark
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens Bukh
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Copenhagen University Hospital—Hvidovre, Hvidovre, Denmark
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Judith Margarete Gottwein
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Copenhagen University Hospital—Hvidovre, Hvidovre, Denmark
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Arvind H. Patel
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Krystyna Bieńkowska-Szewczyk
- Laboratory of Virus Molecular Biology, Intercollegiate Faculty of Biotechnology of the University of Gdańsk and Medical University of Gdańsk, Gdańsk, Poland
| | - Katarzyna Grzyb
- Laboratory of Virus Molecular Biology, Intercollegiate Faculty of Biotechnology of the University of Gdańsk and Medical University of Gdańsk, Gdańsk, Poland
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5
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Yato K, Matsuda M, Watanabe N, Watashi K, Aizaki H, Kato T, Tamura K, Wakita T, Muramatsu M, Suzuki R. Induction of neutralizing antibodies against hepatitis C virus by a subviral particle-based DNA vaccine. Antiviral Res 2022; 199:105266. [DOI: 10.1016/j.antiviral.2022.105266] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 02/09/2022] [Accepted: 02/17/2022] [Indexed: 12/26/2022]
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Structural and Biophysical Characterization of the HCV E1E2 Heterodimer for Vaccine Development. Viruses 2021; 13:v13061027. [PMID: 34072451 PMCID: PMC8227786 DOI: 10.3390/v13061027] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 05/20/2021] [Accepted: 05/25/2021] [Indexed: 02/07/2023] Open
Abstract
An effective vaccine for the hepatitis C virus (HCV) is a major unmet medical and public health need, and it requires an antigen that elicits immune responses to multiple key conserved epitopes. Decades of research have generated a number of vaccine candidates; based on these data and research through clinical development, a vaccine antigen based on the E1E2 glycoprotein complex appears to be the best choice. One bottleneck in the development of an E1E2-based vaccine is that the antigen is challenging to produce in large quantities and at high levels of purity and antigenic/functional integrity. This review describes the production and characterization of E1E2-based vaccine antigens, both membrane-associated and a novel secreted form of E1E2, with a particular emphasis on the major challenges facing the field and how those challenges can be addressed.
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7
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From Structural Studies to HCV Vaccine Design. Viruses 2021; 13:v13050833. [PMID: 34064532 PMCID: PMC8147963 DOI: 10.3390/v13050833] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 04/21/2021] [Accepted: 04/28/2021] [Indexed: 02/06/2023] Open
Abstract
Hepatitis C virus (HCV) is a serious and growing public health problem despite recent developments of antiviral therapeutics. To achieve global elimination of HCV, an effective cross-genotype vaccine is needed. The failure of previous vaccination trials to elicit an effective cross-reactive immune response demands better vaccine antigens to induce a potent cross-neutralizing response to improve vaccine efficacy. HCV E1 and E2 envelope (Env) glycoproteins are the main targets for neutralizing antibodies (nAbs), which aid in HCV clearance and protection. Therefore, a molecular-level understanding of the nAb responses against HCV is imperative for the rational design of cross-genotype vaccine antigens. Here we summarize the recent advances in structural studies of HCV Env and Env-nAb complexes and how they improve our understanding of immune recognition of HCV. We review the structural data defining HCV neutralization epitopes and conformational plasticity of the Env proteins, and the knowledge applicable to rational vaccine design.
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Abstract
Antibody responses in hepatitis C virus (HCV) have been a rather mysterious research topic for many investigators working in the field. Chronic HCV infection is often associated with dysregulation of immune functions particularly in B cells, leading to abnormal lymphoproliferation or the production of autoantibodies that exacerbate inflammation and extrahepatic diseases. When considering the antiviral function of antibody, it was difficult to endorse its role in HCV protection, whereas T-cell response has been shown unequivocally critical for natural recovery. Recent breakthroughs in the study of HCV and antigen-specific antibody responses provide important insights into viral vulnerability to antibodies and the immunogenetic and structural properties of the neutralizing antibodies. The new knowledge reinvigorates HCV vaccine research by illuminating a new path for the rational design of vaccine antigens to elicit broadly neutralizing antibodies for protection.
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Affiliation(s)
- Mansun Law
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, California 92109, USA
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9
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Belz TF, Olson ME, Giang E, Law M, Janda KD. Evaluation of a Series of Lipidated Tucaresol Adjuvants in a Hepatitis C Virus Vaccine Model. ACS Med Chem Lett 2020; 11:2428-2432. [PMID: 33335664 DOI: 10.1021/acsmedchemlett.0c00413] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 10/23/2020] [Indexed: 01/02/2023] Open
Abstract
Hepatitis C virus (HCV) infections represent a global health challenge; however, developing a vaccine for treatment of HCV infection has remained difficult as heterogeneous HCV contains distinct genotypes, and each genotype contains various subtypes and different envelope glycoproteins. Currently, there is no effective preventive vaccine for achieving global control over HCV. In our efforts to improve upon current HCV vaccines we designed a synthetically accessible adjuvant platform, wherein we synthesized 11 novel lipidated tucaresol analogues to assess their immunological potential. Using a tucaresol-based adjuvant approach, truncated lipid-variants together with an engineered E1E2 antigen construct, namely E2ΔTM3, elicited antibody (Ab) responses that were significantly higher than tucaresol. In sum, antibody end-point titer values largely corroborated HCV neutralization data with a simplified lipidated tucaresol variant affording the highest end point titer and % neutralization. This study lays the groundwork for additional permutations in tucaresol adjuvant design, including the examination of other proteins in vaccine development.
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Affiliation(s)
- Tyson F. Belz
- Department of Chemistry, Department of Immunology and Microbial Science, The Skaggs Institute for Chemical Biology, The Worm Institute of Research and Medicine (WIRM), The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Margaret E. Olson
- Department of Chemistry, Department of Immunology and Microbial Science, The Skaggs Institute for Chemical Biology, The Worm Institute of Research and Medicine (WIRM), The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
- College of Pharmacy, Roosevelt University, 1400 North Roosevelt Boulevard, Schaumburg, Illinois 60173, United States
| | - Erick Giang
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Mansun Law
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Kim D. Janda
- Department of Chemistry, Department of Immunology and Microbial Science, The Skaggs Institute for Chemical Biology, The Worm Institute of Research and Medicine (WIRM), The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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Billesbølle CB, Azumaya CM, Kretsch RC, Powers AS, Gonen S, Schneider S, Arvedson T, Dror RO, Cheng Y, Manglik A. Structure of hepcidin-bound ferroportin reveals iron homeostatic mechanisms. Nature 2020; 586:807-811. [PMID: 32814342 PMCID: PMC7906036 DOI: 10.1038/s41586-020-2668-z] [Citation(s) in RCA: 145] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 07/15/2020] [Indexed: 01/01/2023]
Abstract
The serum iron level in humans is tightly controlled by the action of the hormone hepcidin on the iron efflux transporter ferroportin. Hepcidin regulates iron absorption and recycling by inducing ferroportin internalization and degradation1. Aberrant ferroportin activity can lead to diseases of iron overload, like hemochromatosis, or iron limitation anemias2. Here, we determined cryogenic electron microscopy (cryo-EM) structures of ferroportin in lipid nanodiscs, both in the apo state and in complex with cobalt, an iron mimetic, and hepcidin. These structures and accompanying molecular dynamics simulations identify two metal binding sites within the N- and C-domains of ferroportin. Hepcidin binds ferroportin in an outward-open conformation and completely occludes the iron efflux pathway to inhibit transport. The carboxy-terminus of hepcidin directly contacts the divalent metal in the ferroportin C-domain. We further show that hepcidin binding to ferroportin is coupled to iron binding, with an 80-fold increase in hepcidin affinity in the presence of iron. These results suggest a model for hepcidin regulation of ferroportin, where only iron loaded ferroportin molecules are targeted for degradation. More broadly, our structural and functional insights are likely to enable more targeted manipulation of the hepcidin-ferroportin axis in disorders of iron homeostasis.
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Affiliation(s)
- Christian B Billesbølle
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
| | - Caleigh M Azumaya
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA
| | - Rachael C Kretsch
- Department of Computer Science, Stanford University, Stanford, CA, USA.,Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA.,Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA.,Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA.,Biophysics Program, Stanford University, Stanford, CA, USA
| | - Alexander S Powers
- Department of Computer Science, Stanford University, Stanford, CA, USA.,Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA.,Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA.,Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA.,Department of Chemistry, Stanford University, Stanford, CA, USA
| | - Shane Gonen
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA.,Howard Hughes Medical Institute, University of California San Francisco, San Francisco, CA, USA.,Department of Molecular Biology and Biochemistry, University of California, Irvine, Biological Sciences III, Irvine, CA, USA
| | - Simon Schneider
- Institute of Biochemistry, Goethe University Frankfurt, Max-von-Laue-Straße 9, Frankfurt am Main, Germany
| | - Tara Arvedson
- Department of Oncology Research, Amgen Inc., South San Francisco, CA, USA
| | - Ron O Dror
- Department of Computer Science, Stanford University, Stanford, CA, USA.,Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA.,Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA.,Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA.,Biophysics Program, Stanford University, Stanford, CA, USA
| | - Yifan Cheng
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA. .,Howard Hughes Medical Institute, University of California San Francisco, San Francisco, CA, USA.
| | - Aashish Manglik
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA. .,Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, CA, USA.
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11
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Czarnota A, Offersgaard A, Pihl AF, Prentoe J, Bukh J, Gottwein JM, Bieńkowska-Szewczyk K, Grzyb K. Specific Antibodies Induced by Immunization with Hepatitis B Virus-Like Particles Carrying Hepatitis C Virus Envelope Glycoprotein 2 Epitopes Show Differential Neutralization Efficiency. Vaccines (Basel) 2020; 8:vaccines8020294. [PMID: 32532076 PMCID: PMC7350033 DOI: 10.3390/vaccines8020294] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 05/30/2020] [Accepted: 06/06/2020] [Indexed: 12/12/2022] Open
Abstract
Hepatitis C virus (HCV) infection with associated chronic liver diseases is a major health problem worldwide. Here, we designed hepatitis B virus (HBV) small surface antigen (sHBsAg) virus-like particles (VLPs) presenting different epitopes derived from the HCV E2 glycoprotein (residues 412-425, 434-446, 502-520, and 523-535 of isolate H77C). Epitopes were selected based on their amino acid sequence conservation and were previously reported as targets of HCV neutralizing antibodies. Chimeric VLPs obtained in the Leishmania tarentolae expression system, in combination with the adjuvant Addavax, were used to immunize mice. Although all VLPs induced strong humoral responses, only antibodies directed against HCV 412-425 and 523-535 epitopes were able to react with the native E1E2 glycoprotein complexes of different HCV genotypes in ELISA. Neutralization assays against genotype 1-6 cell culture infectious HCV (HCVcc), revealed that only VLPs carrying the 412-425 epitope induced efficient HCV cross-neutralizing antibodies, but with isolate specific variations in efficacy that could not necessarily be explained by differences in epitope sequences. In contrast, antibodies targeting 434-446, 502-520, and 523-535 epitopes were not neutralizing HCVcc, highlighting the importance of conformational antibodies for efficient virus neutralization. Thus, 412-425 remains the most promising linear E2 epitope for further bivalent, rationally designed vaccine research.
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Affiliation(s)
- Anna Czarnota
- Laboratory of Virus Molecular Biology, Intercollegiate Faculty of Biotechnology, University of Gdańsk, 80-309 Gdańsk, Poland; (A.C.); (K.B.-S.)
| | - Anna Offersgaard
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Hvidovre Hospital, 2650 Hvidovre, Denmark; (A.O.); (A.F.P.); (J.P.); (J.B.); (J.M.G.)
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Anne Finne Pihl
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Hvidovre Hospital, 2650 Hvidovre, Denmark; (A.O.); (A.F.P.); (J.P.); (J.B.); (J.M.G.)
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Jannick Prentoe
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Hvidovre Hospital, 2650 Hvidovre, Denmark; (A.O.); (A.F.P.); (J.P.); (J.B.); (J.M.G.)
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Jens Bukh
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Hvidovre Hospital, 2650 Hvidovre, Denmark; (A.O.); (A.F.P.); (J.P.); (J.B.); (J.M.G.)
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Judith Margarete Gottwein
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases, Hvidovre Hospital, 2650 Hvidovre, Denmark; (A.O.); (A.F.P.); (J.P.); (J.B.); (J.M.G.)
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Krystyna Bieńkowska-Szewczyk
- Laboratory of Virus Molecular Biology, Intercollegiate Faculty of Biotechnology, University of Gdańsk, 80-309 Gdańsk, Poland; (A.C.); (K.B.-S.)
| | - Katarzyna Grzyb
- Laboratory of Virus Molecular Biology, Intercollegiate Faculty of Biotechnology, University of Gdańsk, 80-309 Gdańsk, Poland; (A.C.); (K.B.-S.)
- Correspondence:
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Stejskal L, Lees WD, Moss DS, Palor M, Bingham RJ, Shepherd AJ, Grove J. Flexibility and intrinsic disorder are conserved features of hepatitis C virus E2 glycoprotein. PLoS Comput Biol 2020; 16:e1007710. [PMID: 32109245 PMCID: PMC7065822 DOI: 10.1371/journal.pcbi.1007710] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 03/11/2020] [Accepted: 02/04/2020] [Indexed: 12/15/2022] Open
Abstract
The glycoproteins of hepatitis C virus, E1E2, are unlike any other viral fusion machinery yet described, and are the current focus of immunogen design in HCV vaccine development; thus, making E1E2 both scientifically and medically important. We used pre-existing, but fragmentary, structures to model a complete ectodomain of the major glycoprotein E2 from three strains of HCV. We then performed molecular dynamic simulations to explore the conformational landscape of E2, revealing a number of important features. Despite high sequence divergence, and subtle differences in the models, E2 from different strains behave similarly, possessing a stable core flanked by highly flexible regions, some of which perform essential functions such as receptor binding. Comparison with sequence data suggest that this consistent behaviour is conferred by a network of conserved residues that act as hinge and anchor points throughout E2. The variable regions (HVR-1, HVR-2 and VR-3) exhibit particularly high flexibility, and bioinformatic analysis suggests that HVR-1 is a putative intrinsically disordered protein region. Dynamic cross-correlation analyses demonstrate intramolecular communication and suggest that specific regions, such as HVR-1, can exert influence throughout E2. To support our computational approach we performed small-angle X-ray scattering with purified E2 ectodomain; this data was consistent with our MD experiments, suggesting a compact globular core with peripheral flexible regions. This work captures the dynamic behaviour of E2 and has direct relevance to the interaction of HCV with cell-surface receptors and neutralising antibodies.
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Affiliation(s)
- Lenka Stejskal
- Institute of Immunity and Transplantation, Division of Infection and Immunity, University College London, London, United Kingdom
- Institute of Structural and Molecular Biology, Birkbeck College, London, United Kingdom
| | - William D. Lees
- Institute of Structural and Molecular Biology, Birkbeck College, London, United Kingdom
| | - David S. Moss
- Institute of Structural and Molecular Biology, Birkbeck College, London, United Kingdom
| | - Machaela Palor
- Institute of Immunity and Transplantation, Division of Infection and Immunity, University College London, London, United Kingdom
| | - Richard J. Bingham
- Department of Biological Sciences, University of Huddersfield, Huddersfield, United Kingdom
| | - Adrian J. Shepherd
- Institute of Structural and Molecular Biology, Birkbeck College, London, United Kingdom
| | - Joe Grove
- Institute of Immunity and Transplantation, Division of Infection and Immunity, University College London, London, United Kingdom
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Yost SA, Wang Y, Marcotrigiano J. Hepatitis C Virus Envelope Glycoproteins: A Balancing Act of Order and Disorder. Front Immunol 2018; 9:1917. [PMID: 30197646 PMCID: PMC6117417 DOI: 10.3389/fimmu.2018.01917] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Accepted: 08/02/2018] [Indexed: 12/16/2022] Open
Abstract
Chronic hepatitis C virus infection often leads to liver cirrhosis and primary liver cancer. In 2015, an estimated 71 million people were living with chronic HCV. Although infection rates have decreased in many parts of the world over the last several decades, incidence of HCV infection doubled between 2010 and 2014 in the United States mainly due to increases in intravenous drug use. The approval of direct acting antiviral treatments is a necessary component in the elimination of HCV, but inherent barriers to treatment (e.g., cost, lack of access to healthcare, adherence to treatment, resistance, etc.) prevent dramatic improvements in infection rates. An effective HCV vaccine would significantly slow the spread of the disease. Difficulties in the development of an HCV culture model system and expression of properly folded- and natively modified-HCV envelope glycoproteins E1 and E2 have hindered vaccine development efforts. The recent structural and biophysical studies of these proteins have demonstrated that the binding sites for the cellular receptor CD-81 and neutralizing antibodies are highly flexible in nature, which complicate vaccine design. Furthermore, the interactions between E1 and E2 throughout HCV infection is poorly understood, and structural flexibility may play a role in shielding antigenic epitopes during infection. Here we discuss the structural complexities of HCV E1 and E2.
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Affiliation(s)
- Samantha A Yost
- Department of Chemistry and Chemical Biology, Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, NJ, United States
| | - Yuanyuan Wang
- Department of Chemistry and Chemical Biology, Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, NJ, United States.,Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Joseph Marcotrigiano
- Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
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