1
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Vaknin A, Grossman A, Durham ND, Lupovitz I, Goren S, Golani G, Roichman Y, Munro JB, Sorkin R. Ebola Virus Glycoprotein Strongly Binds to Membranes in the Absence of Receptor Engagement. ACS Infect Dis 2024; 10:1590-1601. [PMID: 38684073 PMCID: PMC11091876 DOI: 10.1021/acsinfecdis.3c00622] [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: 11/15/2023] [Revised: 04/07/2024] [Accepted: 04/09/2024] [Indexed: 05/02/2024]
Abstract
Ebola virus (EBOV) is an enveloped virus that must fuse with the host cell membrane in order to release its genome and initiate infection. This process requires the action of the EBOV envelope glycoprotein (GP), encoded by the virus, which resides in the viral envelope and consists of a receptor binding subunit, GP1, and a membrane fusion subunit, GP2. Despite extensive research, a mechanistic understanding of the viral fusion process is incomplete. To investigate GP-membrane association, a key step in the fusion process, we used two approaches: high-throughput measurements of single-particle diffusion and single-molecule measurements with optical tweezers. Using these methods, we show that the presence of the endosomal Niemann-Pick C1 (NPC1) receptor is not required for primed GP-membrane binding. In addition, we demonstrate this binding is very strong, likely attributed to the interaction between the GP fusion loop and the membrane's hydrophobic core. Our results also align with previously reported findings, emphasizing the significance of acidic pH in the protein-membrane interaction. Beyond Ebola virus research, our approach provides a powerful toolkit for studying other protein-membrane interactions, opening new avenues for a better understanding of protein-mediated membrane fusion events.
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Affiliation(s)
- Alisa Vaknin
- School
of Chemistry, Raymond & Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
- Center
for Physics and Chemistry of Living Systems, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Alon Grossman
- School
of Chemistry, Raymond & Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
- Center
for Physics and Chemistry of Living Systems, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Natasha D. Durham
- Department
of Microbiology and Physiological Systems, University of Massachusetts Chan Medical School, Worcester, Massachusetts 01605, United States
| | - Inbal Lupovitz
- School
of Chemistry, Raymond & Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
- Center
for Physics and Chemistry of Living Systems, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Shahar Goren
- School
of Chemistry, Raymond & Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
- Center
for Physics and Chemistry of Living Systems, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Gonen Golani
- Department
of Physics and Haifa Research Center for Theoretical Physics and Astrophysics, University of Haifa, Haifa 3498838, Israel
| | - Yael Roichman
- School
of Chemistry, Raymond & Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
- Center
for Physics and Chemistry of Living Systems, Tel Aviv University, Tel Aviv 6997801, Israel
- Raymond
and Beverly Sackler School of Physics & Astronomy, Tel Aviv University, Tel Aviv 6997801, Israel
| | - James B. Munro
- Department
of Microbiology and Physiological Systems, University of Massachusetts Chan Medical School, Worcester, Massachusetts 01605, United States
- Department
of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, Massachusetts 01605, United States
| | - Raya Sorkin
- School
of Chemistry, Raymond & Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
- Center
for Physics and Chemistry of Living Systems, Tel Aviv University, Tel Aviv 6997801, Israel
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2
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Bird GH, Patten JJ, Zavadoski W, Barucci N, Godes M, Moyer BM, Owen CD, DaSilva-Jardine P, Neuberg DS, Bowen RA, Davey RA, Walensky LD. A stapled lipopeptide platform for preventing and treating highly pathogenic viruses of pandemic potential. Nat Commun 2024; 15:274. [PMID: 38177138 PMCID: PMC10766962 DOI: 10.1038/s41467-023-44361-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 12/11/2023] [Indexed: 01/06/2024] Open
Abstract
The continued emergence of highly pathogenic viruses, which either thwart immune- and small molecule-based therapies or lack interventions entirely, mandates alternative approaches, particularly for prompt and facile pre- and post-exposure prophylaxis. Many highly pathogenic viruses, including coronaviruses, employ the six-helix bundle heptad repeat membrane fusion mechanism to achieve infection. Although heptad-repeat-2 decoys can inhibit viral entry by blocking six-helix bundle assembly, the biophysical and pharmacologic liabilities of peptides have hindered their clinical development. Here, we develop a chemically stapled lipopeptide inhibitor of SARS-CoV-2 as proof-of-concept for the platform. We show that our lead compound blocks infection by a spectrum of SARS-CoV-2 variants, exhibits mucosal persistence upon nasal administration, demonstrates enhanced stability compared to prior analogs, and mitigates infection in hamsters. We further demonstrate that our stapled lipopeptide platform yields nanomolar inhibitors of respiratory syncytial, Ebola, and Nipah viruses by targeting heptad-repeat-1 domains, which exhibit strikingly low mutation rates, enabling on-demand therapeutic intervention to combat viral outbreaks.
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Affiliation(s)
- Gregory H Bird
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
- Linde Program in Cancer Chemical Biology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
| | - J J Patten
- Department of Microbiology, National Emerging Infectious Diseases Laboratories, Boston University, Boston, MA, 02118, USA
| | | | | | - Marina Godes
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
- Linde Program in Cancer Chemical Biology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
| | - Benjamin M Moyer
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
- Linde Program in Cancer Chemical Biology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
| | - Callum D Owen
- Department of Microbiology, National Emerging Infectious Diseases Laboratories, Boston University, Boston, MA, 02118, USA
| | | | - Donna S Neuberg
- Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
| | - Richard A Bowen
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO, 80523, USA
| | - Robert A Davey
- Department of Microbiology, National Emerging Infectious Diseases Laboratories, Boston University, Boston, MA, 02118, USA
| | - Loren D Walensky
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA.
- Linde Program in Cancer Chemical Biology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA.
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3
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Abdul-Rahman T, Lawal L, Meale E, Ajetunmobi OA, Toluwalashe S, Alao UH, Ghosh S, Garg N, Aborode AT, Wireko AA, Mehta A, Sikora K. Inequitable access to Ebola vaccines and the resurgence of Ebola in Africa: A state of arts review. J Med Virol 2023; 95:e28986. [PMID: 37534818 DOI: 10.1002/jmv.28986] [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: 01/26/2023] [Revised: 05/29/2023] [Accepted: 07/13/2023] [Indexed: 08/04/2023]
Abstract
The Ebola virus, a member of the filoviridae family of viruses, is responsible for causing Ebola Virus Disease (EVD) with a case fatality rate as high as 50%. The largest EVD outbreak was recorded in West Africa from March 2013 to June 2016, leading to over 28 000 cases and 11 000 deaths. It affected several countries, including Nigeria, Senegal, Guinea, Liberia, and Sierra Leone. Until then, EVD was predominantly reported in remote villages in central and west Africa close to tropical rainforests. Human mobility, behavioral and cultural norms, the use of bushmeat, burial customs, preference for traditional remedies and treatments, and resistance to health interventions are just a few of the social factors that considerably aid and amplify the risk of transmission. The scale and persistence of recent ebola outbreaks, as well as the risk of widespread global transmission and its ability for bioterrorism, have led to a rethinking of public health strategies to curb the disease, such as the expedition of Ebola vaccine production. However, as vaccine production lags in the subcontinent, among other challenges, the risk of another ebola outbreak is likely and feared by public health authorities in the region. This review describes the inequality of vaccine production in Africa and the resurgence of EVD, emphasizing the significance of health equality.
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Affiliation(s)
- Toufik Abdul-Rahman
- Medical Institute, Sumy State University, Sumy, Ukraine
- ICORMed Collaborative, Sumy, Ukraine
| | - Lukman Lawal
- Faculty of Clinical Sciences, University of Ilorin, Ilorin, Nigeria
| | - Emily Meale
- Rowan University School of Osteopathic Medicine, Stratford, New Jersey, USA
| | | | - Soyemi Toluwalashe
- Lagos State University of College of Medicine, Faculty of Clinical Sciences, Ikeja, Nigeria
| | - Uthman Hassan Alao
- Department of Biomedical Laboratory Science, Faculty of Basic Medical Sciences, University of Ibadan, Ibadan, Nigeria
| | - Shankhaneel Ghosh
- Institute of Medical Sciences and SUM Hospital, Siksha 'O' Anusandhan, Bhubaneswar, India
| | - Neil Garg
- Rowan University School of Osteopathic Medicine, Stratford, New Jersey, USA
| | | | - Andrew Awuah Wireko
- Medical Institute, Sumy State University, Sumy, Ukraine
- ICORMed Collaborative, Sumy, Ukraine
| | - Aashna Mehta
- Faculty of Medicine, University of Debrecen, Debrecen, Hungary
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4
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Ahmed N, El-Nakib HE, Ramsis MM, Albably NO, Wober J, Weigand JJ, Schwedtmann K, Zierau O, Abadi AH. Structure-Activity Relationships of Triphenylethylene Derivatives and Their Evaluation as Anticancer and Antiviral Agents. ACS OMEGA 2023; 8:25903-25923. [PMID: 37521647 PMCID: PMC10373199 DOI: 10.1021/acsomega.3c01682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 06/27/2023] [Indexed: 08/01/2023]
Abstract
Tamoxifen (TAM) is a selective estrogen receptor modulator (SERM) that is used in the treatment of breast cancer, yet with the risk of developing uterine cancer. A perfect SERM would act as an estrogen activator on bones, the cardiovascular system, and the central nervous system while providing neutral or estrogen blocking effects on the breast and the uterus. Herein, we report on the design, synthesis, and evaluation of new rigid and flexible TAM analogues. Mainly, a chloro substituent is introduced at the para position of the TAM ring C blocking the CYP2D6 hydroxylation site. Most compounds showed estrogenic activity higher than TAM using the yeast estrogen screen assays, indicating the determinant role of the chloro substituent upon functional activity. Despite being estrogenic, compound 2B showed potent antiproliferative activity in the NCI 60 cell lines with mean GI50 = 3.67 μM, GI50 = 1.05 μM on MCF-7 cell lines, and GI50 = 1.30 μM on MDA-MB-231. The estrogenic activity of compound 2B was further confirmed by stimulating alkaline phosphatase in Ishikawa cells, and it showed no increase in relative uterine wet weight in ovariectomized rats. Compound 2F showed EC90 = 0.31 μg/mL and SI90 = 60 against Ebola virus; this is 200-fold more potent than the positive control favipiravir. This is the first time to report estrogenic triphenylethylenes as anti-EBOV agents. The anti-EBOV activity reported is a function of the substitution pattern of the scaffold rather than the functional activity. Moreover, compound 3D showed excellent PO pharmacokinetic properties in mice. In conclusion, for this class of TAM-like compounds, the blockage of the p-position of ring C is decisive for the functional activity; meanwhile, the triarylethylene substitution pattern is detrimental for the antiviral activity.
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Affiliation(s)
- Nermin
S. Ahmed
- Faculty
of Pharmacy and Biotechnology, Department of Pharmaceutical Chemistry, German University in Cairo, 11835 Cairo, Egypt
| | - Heba E. El-Nakib
- Faculty
of Pharmacy and Biotechnology, Department of Pharmaceutical Chemistry, German University in Cairo, 11835 Cairo, Egypt
| | - Marian M. Ramsis
- Faculty
of Pharmacy and Biotechnology, Department of Pharmaceutical Chemistry, German University in Cairo, 11835 Cairo, Egypt
| | - Nouran O. Albably
- Faculty
of Pharmacy and Biotechnology, Department of Pharmaceutical Chemistry, German University in Cairo, 11835 Cairo, Egypt
| | - Jannette Wober
- Faculty
of Biology, Institute of Zoology, Technische
Universität Dresden, 01062 Dresden, Germany
| | - Jan J. Weigand
- Faculty
of Chemistry and Food Chemistry, Institute of Inorganic Molecular
Chemistry, Technische Universität
Dresden, 01062 Dresden, Germany
| | - Kai Schwedtmann
- Faculty
of Chemistry and Food Chemistry, Institute of Inorganic Molecular
Chemistry, Technische Universität
Dresden, 01062 Dresden, Germany
| | - Oliver Zierau
- Faculty
of Biology, Institute of Zoology, Technische
Universität Dresden, 01062 Dresden, Germany
| | - Ashraf H. Abadi
- Faculty
of Pharmacy and Biotechnology, Department of Pharmaceutical Chemistry, German University in Cairo, 11835 Cairo, Egypt
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5
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Scherm MJ, Gangloff M, Gay NJ. Activation of Toll-like receptor 4 by Ebola virus-shed glycoprotein is direct and requires the internal fusion loop but not glycosylation. Cell Rep 2022; 41:111562. [PMID: 36288690 PMCID: PMC9637988 DOI: 10.1016/j.celrep.2022.111562] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 09/16/2022] [Accepted: 10/04/2022] [Indexed: 12/03/2022] Open
Abstract
Infection by the Ebola virus, a member of the Filoviridae family of RNA viruses, leads to acute viral hemorrhagic fever. End-stage Ebola virus disease is characterized by a cytokine storm that causes tissue damage, vascular disintegration, and multi-organ failure. Previous studies showed that a shed form of the viral spike glycoprotein (sGP1,2) drives this hyperinflammatory response by activating Toll-like receptor 4 (TLR4). Here, we find that glycosylation is not required for activation of TLR4 by sGP1,2 and identify the internal fusion loop (IFL) as essential for inflammatory signaling. sGP1,2 competes with lipid antagonists of TLR4, and the IFL interacts directly with TLR4 and co-receptor MD2. Together, these findings indicate that sGP1,2 activates TLR4 analogously to bacterial agonist lipopolysaccharide (LPS) by binding into a hydrophobic pocket in MD2 and promoting the formation of an active heterotetramer. This conclusion is supported by docking studies that predict binding sites for sGP1,2 on TLR4 and MD2.
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Affiliation(s)
- Michael J. Scherm
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA, UK
| | - Monique Gangloff
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA, UK
| | - Nicholas J. Gay
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA, UK,Corresponding author
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6
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Peng W, Rayaprolu V, Parvate AD, Pronker MF, Hui S, Parekh D, Shaffer K, Yu X, Saphire EO, Snijder J. Glycan shield of the ebolavirus envelope glycoprotein GP. Commun Biol 2022; 5:785. [PMID: 35927436 PMCID: PMC9352669 DOI: 10.1038/s42003-022-03767-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 07/25/2022] [Indexed: 11/09/2022] Open
Abstract
The envelope glycoprotein GP of the ebolaviruses is essential for host cell entry and the primary target of the host antibody response. GP is heavily glycosylated with up to 17 N-linked sites, numerous O-linked glycans in its disordered mucin-like domain (MLD), and three predicted C-linked mannosylation sites. Glycosylation is important for host cell attachment, GP stability and fusion activity, and shielding from neutralization by serum antibodies. Here, we use glycoproteomics to profile the site-specific glycosylation patterns of ebolavirus GP. We detect up to 16 unique O-linked glycosylation sites in the MLD, and two O-linked sites in the receptor-binding GP1 subunit. Multiple O-linked glycans are observed within N-linked glycosylation sequons, suggesting crosstalk between the two types of modifications. We confirmed C-mannosylation of W288 in full-length trimeric GP. We find complex glycosylation at the majority of N-linked sites, while the conserved sites N257 and especially N563 are enriched in unprocessed glycans, suggesting a role in host-cell attachment via DC-SIGN/L-SIGN. Our findings illustrate how N-, O-, and C-linked glycans together build the heterogeneous glycan shield of GP, guiding future immunological studies and functional interpretation of ebolavirus GP-antibody interactions. Site-specific N-, O-, and C-linked glycans are characterized in the ebolavirus envelope glycoprotein GP using mass spectrometry-based glycoproteomics.
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Affiliation(s)
- Weiwei Peng
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584, CH, Utrecht, The Netherlands
| | - Vamseedhar Rayaprolu
- Center for Infectious Disease and Vaccine Discovery, La Jolla Institute for Immunology, La Jolla, CA, 92037, USA.,Pacific Northwest Center for CryoEM, Portland, OR, 97225, USA
| | - Amar D Parvate
- Center for Infectious Disease and Vaccine Discovery, La Jolla Institute for Immunology, La Jolla, CA, 92037, USA.,Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, 99354, USA
| | - Matti F Pronker
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584, CH, Utrecht, The Netherlands
| | - Sean Hui
- Center for Infectious Disease and Vaccine Discovery, La Jolla Institute for Immunology, La Jolla, CA, 92037, USA.,Molecular Microbiology and Microbial Pathogenesis Program, Washington University School of Medicine, Saint Louis, MO, 63108, USA
| | - Diptiben Parekh
- Center for Infectious Disease and Vaccine Discovery, La Jolla Institute for Immunology, La Jolla, CA, 92037, USA
| | - Kelly Shaffer
- Center for Infectious Disease and Vaccine Discovery, La Jolla Institute for Immunology, La Jolla, CA, 92037, USA.,Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Xiaoying Yu
- Center for Infectious Disease and Vaccine Discovery, La Jolla Institute for Immunology, La Jolla, CA, 92037, USA
| | - Erica O Saphire
- Center for Infectious Disease and Vaccine Discovery, La Jolla Institute for Immunology, La Jolla, CA, 92037, USA.,Department of Medicine, University of California, San Diego, La Jolla, CA, 92039, USA
| | - Joost Snijder
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584, CH, Utrecht, The Netherlands.
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7
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Schoeder CT, Gilchuk P, Sangha AK, Ledwitch KV, Malherbe DC, Zhang X, Binshtein E, Williamson LE, Martina CE, Dong J, Armstrong E, Sutton R, Nargi R, Rodriguez J, Kuzmina N, Fiala B, King NP, Bukreyev A, Crowe JE, Meiler J. Epitope-focused immunogen design based on the ebolavirus glycoprotein HR2-MPER region. PLoS Pathog 2022; 18:e1010518. [PMID: 35584193 PMCID: PMC9170092 DOI: 10.1371/journal.ppat.1010518] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 06/06/2022] [Accepted: 04/12/2022] [Indexed: 01/09/2023] Open
Abstract
The three human pathogenic ebolaviruses: Zaire (EBOV), Bundibugyo (BDBV), and Sudan (SUDV) virus, cause severe disease with high fatality rates. Epitopes of ebolavirus glycoprotein (GP) recognized by antibodies with binding breadth for all three ebolaviruses are of major interest for rational vaccine design. In particular, the heptad repeat 2 -membrane-proximal external region (HR2-MPER) epitope is relatively conserved between EBOV, BDBV, and SUDV GP and targeted by human broadly-neutralizing antibodies. To study whether this epitope can serve as an immunogen for the elicitation of broadly-reactive antibody responses, protein design in Rosetta was employed to transplant the HR2-MPER epitope identified from a co-crystal structure with the known broadly-reactive monoclonal antibody (mAb) BDBV223 onto smaller scaffold proteins. From computational analysis, selected immunogen designs were produced as recombinant proteins and functionally validated, leading to the identification of a sterile alpha motif (SAM) domain displaying the BDBV-HR2-MPER epitope near its C terminus as a promising candidate. The immunogen was fused to one component of a self-assembling, two-component nanoparticle and tested for immunogenicity in rabbits. Robust titers of cross-reactive serum antibodies to BDBV and EBOV GPs and moderate titers to SUDV GP were induced following immunization. To confirm the structural composition of the immunogens, solution NMR studies were conducted and revealed structural flexibility in the C-terminal residues of the epitope. Overall, our study represents the first report on an epitope-focused immunogen design based on the structurally challenging BDBV-HR2-MPER epitope.
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Affiliation(s)
- Clara T. Schoeder
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, United States of America
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, United States of America
- Institute for Drug Discovery, University Leipzig Medical School, Leipzig, Germany
| | - Pavlo Gilchuk
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Tennessee, United States of America
| | - Amandeep K. Sangha
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, United States of America
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Kaitlyn V. Ledwitch
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, United States of America
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Delphine C. Malherbe
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Galveston National Laboratory, Galveston, Texas, United States of America
| | - Xuan Zhang
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, United States of America
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Elad Binshtein
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Tennessee, United States of America
| | - Lauren E. Williamson
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Tennessee, United States of America
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Cristina E. Martina
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, United States of America
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Jinhui Dong
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Tennessee, United States of America
| | - Erica Armstrong
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Tennessee, United States of America
| | - Rachel Sutton
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Tennessee, United States of America
| | - Rachel Nargi
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Tennessee, United States of America
| | - Jessica Rodriguez
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Tennessee, United States of America
| | - Natalia Kuzmina
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Galveston National Laboratory, Galveston, Texas, United States of America
| | - Brooke Fiala
- 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
| | - Neil P. King
- 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
| | - Alexander Bukreyev
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Galveston National Laboratory, Galveston, Texas, United States of America
- Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, Texas, Unites States, United States of America
| | - James E. Crowe
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Tennessee, United States of America
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Departments of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Jens Meiler
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, United States of America
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, United States of America
- Institute for Drug Discovery, University Leipzig Medical School, Leipzig, Germany
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8
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Unique Mode of Antiviral Action of a Marine Alkaloid against Ebola Virus and SARS-CoV-2. Viruses 2022; 14:v14040816. [PMID: 35458549 PMCID: PMC9028129 DOI: 10.3390/v14040816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 03/24/2022] [Accepted: 04/02/2022] [Indexed: 11/16/2022] Open
Abstract
Lamellarin α 20-sulfate is a cell-impenetrable marine alkaloid that can suppress infection that is mediated by the envelope glycoprotein of human immunodeficiency virus type 1. We explored the antiviral action and mechanisms of this alkaloid against emerging enveloped RNA viruses that use endocytosis for infection. The alkaloid inhibited the infection of retroviral vectors that had been pseudotyped with the envelope glycoprotein of Ebola virus and SARS-CoV-2. The antiviral effects of lamellarin were independent of the retrovirus Gag-Pol proteins. Interestingly, although heparin and dextran sulfate suppressed the cell attachment of vector particles, lamellarin did not. In silico structural analyses of the trimeric glycoprotein of the Ebola virus disclosed that the principal lamellarin-binding site is confined to a previously unappreciated cavity near the NPC1-binding site and fusion loop, whereas those for heparin and dextran sulfate were dispersed across the attachment and fusion subunits of the glycoproteins. Notably, lamellarin binding to this cavity was augmented under conditions where the pH was 5.0. These results suggest that the final action of the alkaloid against Ebola virus is specific to events following endocytosis, possibly during conformational glycoprotein changes in the acidic environment of endosomes. Our findings highlight the unique biological and physicochemical features of lamellarin α 20-sulfate and should lead to the further use of broadly reactive antivirals to explore the structural mechanisms of virus replication.
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9
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Giesler RJ, Spaltenstein P, Jacobsen MT, Xu W, Maqueda M, Kay MS. A glutamic acid-based traceless linker to address challenging chemical protein syntheses. Org Biomol Chem 2021; 19:8821-8829. [PMID: 34585207 PMCID: PMC8604549 DOI: 10.1039/d1ob01611c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Native chemical ligation (NCL) enables the total chemical synthesis of proteins. However, poor peptide segment solubility remains a frequently encountered challenge. Here we introduce a traceless linker that can be temporarily attached to Glu side chains to overcome this problem. This strategy employs a new tool, Fmoc-Glu(AlHx)-OH, which can be directly installed using standard Fmoc-based solid-phase peptide synthesis. The incorporated residue, Glu(AlHx), is stable to a wide range of chemical protein synthesis conditions and is removed through palladium-catalyzed transfer under aqueous conditions. General handling characteristics, such as efficient incorporation, stability and rapid removal were demonstrated through a model peptide modified with Glu(AlHx) and a Lys6 solubilizing tag. Glu(AlHx) was incorporated into a highly insoluble peptide segment during the total synthesis of the bacteriocin AS-48. This challenging peptide was successfully synthesized and folded, and it has comparable antimicrobial activity to the native AS-48. We anticipate widespread use of this easy-to-use, robust linker for the preparation of challenging synthetic peptides and proteins.
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Affiliation(s)
- Riley J Giesler
- Department of Biochemistry, University of Utah School of Medicine, 15 North Medical Drive East, Room 4100, Salt Lake City, Utah 84112-5650, USA.
| | - Paul Spaltenstein
- Department of Biochemistry, University of Utah School of Medicine, 15 North Medical Drive East, Room 4100, Salt Lake City, Utah 84112-5650, USA.
| | - Michael T Jacobsen
- Department of Pediatrics, Division of Diabetes and Endocrinology, Stanford University, Palo Alto, CA 94304, USA
| | - Weiliang Xu
- Department of Biochemistry, University of Utah School of Medicine, 15 North Medical Drive East, Room 4100, Salt Lake City, Utah 84112-5650, USA.
| | - Mercedes Maqueda
- Departamento de Microbiología, Universidad de Granada, Avda. Fuentenueva, s/n, 18071 Granada, Spain
| | - Michael S Kay
- Department of Biochemistry, University of Utah School of Medicine, 15 North Medical Drive East, Room 4100, Salt Lake City, Utah 84112-5650, USA.
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10
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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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11
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Pu J, Zhou JT, Liu P, Yu F, He X, Lu L, Jiang S. Viral Entry Inhibitors Targeting Six-Helical Bundle Core Against Highly Pathogenic Enveloped Viruses with Class I Fusion Proteins. Curr Med Chem 2021; 29:700-718. [PMID: 33992055 DOI: 10.2174/0929867328666210511015808] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 02/12/2021] [Accepted: 02/13/2021] [Indexed: 11/22/2022]
Abstract
TypeⅠ enveloped viruses bind to cell receptors through surface glycoproteins to initiate infection or undergo receptor-mediated endocytosis. They also initiate membrane fusion in the acidic environment of endocytic compartments, releasing genetic material into the cell. In the process of membrane fusion, envelope protein exposes fusion peptide, followed by insertion into the cell membrane or endosomal membrane. Further conformational changes ensue in which the type 1 envelope protein forms a typical six-helix bundle structure, shortening the distance between viral and cell membranes so that fusion can occur. Entry inhibitors targeting viral envelope proteins, or host factors, are effective antiviral agents and have been widely studied. Some have been used clinically, such as T20 and Maraviroc for human immunodeficiency virus 1 (HIV-1) or Myrcludex B for hepatitis D virus (HDV). This review focuses on entry inhibitors that target the six-helical bundle core against highly pathogenic enveloped viruses with class I fusion proteins, including retroviruses, coronaviruses, influenza A viruses, paramyxoviruses, and filoviruses.
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Affiliation(s)
- Jing Pu
- Key Laboratory of Medical Molecular Virology of MOE/MOH/CAMS, School of Basic Medical Sciences & Shanghai Public Health Clinical Center, Fudan University, Shanghai 200032, China
| | - Joey Tianyi Zhou
- Institute of High Performance Computing, The Agency for Science, Technology and Research, Singapore
| | - Ping Liu
- Institute of High Performance Computing, The Agency for Science, Technology and Research, Singapore
| | - Fei Yu
- College of Life Sciences, Hebei Agricultural University, Baoding, China
| | - Xiaoyang He
- Beijing Institute of Radiation Medicine, Beijing, China
| | - Lu Lu
- Key Laboratory of Medical Molecular Virology of MOE/MOH/CAMS, School of Basic Medical Sciences & Shanghai Public Health Clinical Center, Fudan University, Shanghai 200032, China
| | - Shibo Jiang
- Key Laboratory of Medical Molecular Virology of MOE/MOH/CAMS, School of Basic Medical Sciences & Shanghai Public Health Clinical Center, Fudan University, Shanghai 200032, China
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12
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Lu M. Single-Molecule FRET Imaging of Virus Spike-Host Interactions. Viruses 2021; 13:v13020332. [PMID: 33669922 PMCID: PMC7924862 DOI: 10.3390/v13020332] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 02/18/2021] [Accepted: 02/18/2021] [Indexed: 02/07/2023] Open
Abstract
As a major surface glycoprotein of enveloped viruses, the virus spike protein is a primary target for vaccines and anti-viral treatments. Current vaccines aiming at controlling the COVID-19 pandemic are mostly directed against the SARS-CoV-2 spike protein. To promote virus entry and facilitate immune evasion, spikes must be dynamic. Interactions with host receptors and coreceptors trigger a cascade of conformational changes/structural rearrangements in spikes, which bring virus and host membranes in proximity for membrane fusion required for virus entry. Spike-mediated viral membrane fusion is a dynamic, multi-step process, and understanding the structure–function-dynamics paradigm of virus spikes is essential to elucidate viral membrane fusion, with the ultimate goal of interventions. However, our understanding of this process primarily relies on individual structural snapshots of endpoints. How these endpoints are connected in a time-resolved manner, and the order and frequency of conformational events underlying virus entry, remain largely elusive. Single-molecule Förster resonance energy transfer (smFRET) has provided a powerful platform to connect structure–function in motion, revealing dynamic aspects of spikes for several viruses: SARS-CoV-2, HIV-1, influenza, and Ebola. This review focuses on how smFRET imaging has advanced our understanding of virus spikes’ dynamic nature, receptor-binding events, and mechanism of antibody neutralization, thereby informing therapeutic interventions.
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Affiliation(s)
- Maolin Lu
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT 06536, USA
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13
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Lee J, Kreutzberger AJB, Odongo L, Nelson EA, Nyenhuis DA, Kiessling V, Liang B, Cafiso DS, White JM, Tamm LK. Ebola virus glycoprotein interacts with cholesterol to enhance membrane fusion and cell entry. Nat Struct Mol Biol 2021; 28:181-189. [PMID: 33462517 PMCID: PMC7992113 DOI: 10.1038/s41594-020-00548-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 12/07/2020] [Indexed: 12/14/2022]
Abstract
Cholesterol serves critical roles in enveloped virus fusion by modulating membrane properties. The glycoprotein (GP) of Ebola virus (EBOV) promotes fusion in the endosome, a process that requires the endosomal cholesterol transporter NPC1. However, the role of cholesterol in EBOV fusion is unclear. Here we show that cholesterol in GP-containing membranes enhances fusion and the membrane-proximal external region and transmembrane (MPER/TM) domain of GP interacts with cholesterol via several glycine residues in the GP2 TM domain, notably G660. Compared to wild-type (WT) counterparts, a G660L mutation caused a more open angle between MPER and TM domains in an MPER/TM construct, higher probability of stalling at hemifusion for GP2 proteoliposomes and lower cell entry of virus-like particles (VLPs). VLPs with depleted cholesterol show reduced cell entry, and VLPs produced under cholesterol-lowering statin conditions show less frequent entry than respective controls. We propose that cholesterol-TM interactions affect structural features of GP2, thereby facilitating fusion and cell entry.
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Affiliation(s)
- Jinwoo Lee
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD, USA
| | - Alex J B Kreutzberger
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA
| | - Laura Odongo
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA
| | - Elizabeth A Nelson
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, USA
- Department of Cell Biology, University of Virginia, Charlottesville, VA, USA
| | - David A Nyenhuis
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, USA
- Department of Chemistry, University of Virginia, Charlottesville, VA, USA
| | - Volker Kiessling
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA
| | - Binyong Liang
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA
| | - David S Cafiso
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, USA
- Department of Chemistry, University of Virginia, Charlottesville, VA, USA
| | - Judith M White
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, USA
- Department of Cell Biology, University of Virginia, Charlottesville, VA, USA
| | - Lukas K Tamm
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, USA.
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA.
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14
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Wilson IA, Stanfield RL. 50 Years of structural immunology. J Biol Chem 2021; 296:100745. [PMID: 33957119 PMCID: PMC8163984 DOI: 10.1016/j.jbc.2021.100745] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/24/2021] [Accepted: 04/30/2021] [Indexed: 12/12/2022] Open
Abstract
Fifty years ago, the first landmark structures of antibodies heralded the dawn of structural immunology. Momentum then started to build toward understanding how antibodies could recognize the vast universe of potential antigens and how antibody-combining sites could be tailored to engage antigens with high specificity and affinity through recombination of germline genes (V, D, J) and somatic mutation. Equivalent groundbreaking structures in the cellular immune system appeared some 15 to 20 years later and illustrated how processed protein antigens in the form of peptides are presented by MHC molecules to T cell receptors. Structures of antigen receptors in the innate immune system then explained their inherent specificity for particular microbial antigens including lipids, carbohydrates, nucleic acids, small molecules, and specific proteins. These two sides of the immune system act immediately (innate) to particular microbial antigens or evolve (adaptive) to attain high specificity and affinity to a much wider range of antigens. We also include examples of other key receptors in the immune system (cytokine receptors) that regulate immunity and inflammation. Furthermore, these antigen receptors use a limited set of protein folds to accomplish their various immunological roles. The other main players are the antigens themselves. We focus on surface glycoproteins in enveloped viruses including SARS-CoV-2 that enable entry and egress into host cells and are targets for the antibody response. This review covers what we have learned over the past half century about the structural basis of the immune response to microbial pathogens and how that information can be utilized to design vaccines and therapeutics.
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MESH Headings
- Adaptive Immunity
- Allergy and Immunology/history
- Animals
- Antibodies, Viral/chemistry
- Antibodies, Viral/genetics
- Antibodies, Viral/immunology
- Antibody Specificity
- Antigen Presentation
- Antigens, Viral/chemistry
- Antigens, Viral/genetics
- Antigens, Viral/immunology
- COVID-19/immunology
- COVID-19/virology
- Crystallography/history
- Crystallography/methods
- History, 20th Century
- History, 21st Century
- Humans
- Immunity, Innate
- Protein Folding
- Protein Interaction Domains and Motifs
- Receptors, Antigen, T-Cell/chemistry
- Receptors, Antigen, T-Cell/genetics
- Receptors, Antigen, T-Cell/immunology
- Receptors, Cytokine/chemistry
- Receptors, Cytokine/genetics
- Receptors, Cytokine/immunology
- SARS-CoV-2/immunology
- SARS-CoV-2/pathogenicity
- V(D)J Recombination
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Affiliation(s)
- Ian A Wilson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, USA; The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California, USA.
| | - Robyn L Stanfield
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, USA
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15
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Barfoot S, Poger D, Mark AE. Understanding the Activated Form of a Class-I Fusion Protein: Modeling the Interaction of the Ebola Virus Glycoprotein 2 with a Lipid Bilayer. Biochemistry 2020; 59:4051-4058. [PMID: 32960042 DOI: 10.1021/acs.biochem.0c00527] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The fusion of the viral and target cell membranes is a key step in the life cycle of all enveloped viruses. Here, a range of structural data is used to generate an evidence-based model of the active conformation of an archetypical type-I fusion protein, the Ebola glycoprotein 2 (GP2). The stability of the trimeric complex is demonstrated using molecular dynamics and validated by simulating the interaction of the complex with a lipid bilayer. In this model, the fusion peptides project away from the central helix bundle parallel to the target membrane. This maximizes contact with the host membrane, enhances lateral stability, and would explain why, when activated, viral fusion proteins are trimeric.
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Affiliation(s)
- Shelley Barfoot
- School of Chemistry & Molecular Biosciences, The University of Queensland, St Lucia, Queensland 4072, Australia
| | - David Poger
- School of Chemistry & Molecular Biosciences, The University of Queensland, St Lucia, Queensland 4072, Australia
| | - Alan E Mark
- School of Chemistry & Molecular Biosciences, The University of Queensland, St Lucia, Queensland 4072, Australia
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16
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A Virion-Based Assay for Glycoprotein Thermostability Reveals Key Determinants of Filovirus Entry and Its Inhibition. J Virol 2020; 94:JVI.00336-20. [PMID: 32611759 DOI: 10.1128/jvi.00336-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 06/26/2020] [Indexed: 11/20/2022] Open
Abstract
Ebola virus (EBOV) entry into cells is mediated by its spike glycoprotein (GP). Following attachment and internalization, virions traffic to late endosomes where GP is cleaved by host cysteine proteases. Cleaved GP then binds its cellular receptor, Niemann-Pick C1. In response to an unknown cellular trigger, GP undergoes conformational rearrangements that drive fusion of viral and endosomal membranes. The temperature-dependent stability (thermostability) of the prefusion conformers of class I viral fusion glycoproteins, including those of filovirus GPs, has provided insights into their propensity to undergo fusion-related rearrangements. However, previously described assays have relied on soluble glycoprotein ectodomains. Here, we developed a simple enzyme-linked immunosorbent assay (ELISA)-based assay that uses the temperature-dependent loss of conformational epitopes to measure thermostability of GP embedded in viral membranes. The base and glycan cap subdomains of all filovirus GPs tested suffered a concerted loss of prefusion conformation at elevated temperatures but did so at different temperature ranges, indicating virus-specific differences in thermostability. Despite these differences, all of these GPs displayed reduced thermostability upon cleavage to GP conformers (GPCL). Surprisingly, acid pH enhanced, rather than decreased, GP thermostability, suggesting it could enhance viral survival in hostile endo/lysosomal compartments. Finally, we confirmed and extended previous findings that some small-molecule inhibitors of filovirus entry destabilize EBOV GP and uncovered evidence that the most potent inhibitors act through multiple mechanisms. We establish the epitope-loss ELISA as a useful tool for studies of filovirus entry, engineering of GP variants with enhanced stability for use in vaccine development, and discovery of new stability-modulating antivirals.IMPORTANCE The development of Ebola virus countermeasures is challenged by our limited understanding of cell entry, especially at the step of membrane fusion. The surface-exposed viral protein, GP, mediates membrane fusion and undergoes major structural rearrangements during this process. The stability of GP at elevated temperatures (thermostability) can provide insights into its capacity to undergo these rearrangements. Here, we describe a new assay that uses GP-specific antibodies to measure GP thermostability under a variety of conditions relevant to viral entry. We show that proteolytic cleavage and acid pH have significant effects on GP thermostability that shed light on their respective roles in viral entry. We also show that the assay can be used to study how small-molecule entry inhibitors affect GP stability. This work provides a simple and readily accessible assay to engineer stabilized GP variants for antiviral vaccines and to discover and improve drugs that act by modulating GP stability.
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17
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Delauzun V, Amigues B, Gaubert A, Leone P, Grange M, Gauthier L, Roussel A. Extracellular vesicles as a platform to study cell-surface membrane proteins. Methods 2020; 180:35-44. [PMID: 32156657 DOI: 10.1016/j.ymeth.2020.03.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 03/03/2020] [Accepted: 03/05/2020] [Indexed: 01/08/2023] Open
Abstract
Producing intact recombinant membrane proteins for structural studies is an inherently challenging task due to their requirement for a cell-lipid environment. Most of the procedures developed involve isolating the protein by solubilization with detergent and further reconstitutions into artificial membranes. These procedures are highly time consuming and suffer from further drawbacks, including low yields and high cost. We describe here an alternative method for rapidly obtaining recombinant cell-surface membrane proteins displayed on extracellular vesicles (EVs) derived from cells in culture. Interaction between these membrane proteins and ligands can be analyzed directly on EVs. Moreover, EVs can also be used for protein structure determination or immunization purposes.
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Affiliation(s)
- Vincent Delauzun
- Architecture et Fonction des Macromolécules Biologiques (AFMB), CNRS, Aix-Marseille Université, UMR 7257, 163 Avenue de Luminy, Case 932, 13009 Marseille, France
| | - Beatrice Amigues
- Architecture et Fonction des Macromolécules Biologiques (AFMB), CNRS, Aix-Marseille Université, UMR 7257, 163 Avenue de Luminy, Case 932, 13009 Marseille, France
| | - Anais Gaubert
- Architecture et Fonction des Macromolécules Biologiques (AFMB), CNRS, Aix-Marseille Université, UMR 7257, 163 Avenue de Luminy, Case 932, 13009 Marseille, France
| | - Philippe Leone
- Architecture et Fonction des Macromolécules Biologiques (AFMB), CNRS, Aix-Marseille Université, UMR 7257, 163 Avenue de Luminy, Case 932, 13009 Marseille, France
| | - Magali Grange
- Architecture et Fonction des Macromolécules Biologiques (AFMB), CNRS, Aix-Marseille Université, UMR 7257, 163 Avenue de Luminy, Case 932, 13009 Marseille, France
| | | | - Alain Roussel
- Architecture et Fonction des Macromolécules Biologiques (AFMB), CNRS, Aix-Marseille Université, UMR 7257, 163 Avenue de Luminy, Case 932, 13009 Marseille, France.
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18
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Monteiro AFM, de Oliveira Viana J, Muratov E, Scotti MT, Scotti L. In Silico Studies against Viral Sexually Transmitted Diseases. Curr Protein Pept Sci 2020; 20:1135-1150. [PMID: 30854957 DOI: 10.2174/1389203720666190311142747] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 01/17/2019] [Accepted: 01/18/2019] [Indexed: 01/02/2023]
Abstract
Sexually Transmitted Diseases (STDs) refer to a variety of clinical syndromes and infections caused by pathogens that can be acquired and transmitted through sexual activity. Among STDs widely reported in the literature, viral sexual diseases have been increasing in a number of cases globally. This emphasizes the need for prevention and treatment. Among the methods widely used in drug planning are Computer-Aided Drug Design (CADD) studies and molecular docking which have the objective of investigating molecular interactions between two molecules to better understand the three -dimensional structural characteristics of the compounds. This review will discuss molecular docking studies applied to viral STDs, such as Ebola virus, Herpes virus and HIV, and reveal promising new drug candidates with high levels of specificity to their respective targets.
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Affiliation(s)
- Alex F M Monteiro
- Program of Natural and Synthetic Bioactive Products (PgPNSB), Health Sciences Center, Federal University of Paraíba, Joao Pessoa-PB, Brazil
| | - Jessika de Oliveira Viana
- Program of Natural and Synthetic Bioactive Products (PgPNSB), Health Sciences Center, Federal University of Paraíba, Joao Pessoa-PB, Brazil
| | - Engene Muratov
- Laboratory for Molecular Modeling, Division of Medicinal Chemistry and Natural Products, Eshelman School of Pharmacy, University of North Carolina, Beard Hall 301, CB#7568, Chapel Hill, NC, 27599, United States
| | - Marcus T Scotti
- Program of Natural and Synthetic Bioactive Products (PgPNSB), Health Sciences Center, Federal University of Paraíba, Joao Pessoa-PB, Brazil
| | - Luciana Scotti
- Program of Natural and Synthetic Bioactive Products (PgPNSB), Health Sciences Center, Federal University of Paraíba, Joao Pessoa-PB, Brazil.,Teaching and Research Management - University Hospital, Federal University of Paraíba, Campus I, 58051-900, João Pessoa-PB, Brazil
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19
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Das DK, Bulow U, Diehl WE, Durham ND, Senjobe F, Chandran K, Luban J, Munro JB. Conformational changes in the Ebola virus membrane fusion machine induced by pH, Ca2+, and receptor binding. PLoS Biol 2020; 18:e3000626. [PMID: 32040508 PMCID: PMC7034923 DOI: 10.1371/journal.pbio.3000626] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 02/21/2020] [Accepted: 01/23/2020] [Indexed: 12/22/2022] Open
Abstract
The Ebola virus (EBOV) envelope glycoprotein (GP) is a membrane fusion machine required for virus entry into cells. Following endocytosis of EBOV, the GP1 domain is cleaved by cellular cathepsins in acidic endosomes, removing the glycan cap and exposing a binding site for the Niemann-Pick C1 (NPC1) receptor. NPC1 binding to cleaved GP1 is required for entry. How this interaction translates to GP2 domain-mediated fusion of viral and endosomal membranes is not known. Here, using a bulk fluorescence dequenching assay and single-molecule Förster resonance energy transfer (smFRET)-imaging, we found that acidic pH, Ca2+, and NPC1 binding synergistically induce conformational changes in GP2 and permit virus-liposome lipid mixing. Acidic pH and Ca2+ shifted the GP2 conformational equilibrium in favor of an intermediate state primed for NPC1 binding. Glycan cap cleavage on GP1 enabled GP2 to transition from a reversible intermediate to an irreversible conformation, suggestive of the postfusion 6-helix bundle; NPC1 binding further promoted transition to the irreversible conformation. Thus, the glycan cap of GP1 may allosterically protect against inactivation of EBOV by premature triggering of GP2. The Ebola virus envelope glycoprotein is a membrane fusion machine required for the virus to enter into host cells. This study presents direct observation of the conformational changes that the envelope glycoprotein undergoes during the membrane fusion process.
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Affiliation(s)
- Dibyendu Kumar Das
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine and Sackler School of Graduate Biomedical Sciences, Boston, Massachusetts, United States of America
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, India
- * E-mail: (JBM); (DKD)
| | - Uriel Bulow
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine and Sackler School of Graduate Biomedical Sciences, Boston, Massachusetts, United States of America
| | - William E. Diehl
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Natasha D. Durham
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine and Sackler School of Graduate Biomedical Sciences, Boston, Massachusetts, United States of America
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Fernando Senjobe
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine and Sackler School of Graduate Biomedical Sciences, Boston, Massachusetts, United States of America
| | - Kartik Chandran
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Jeremy Luban
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - James B. Munro
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine and Sackler School of Graduate Biomedical Sciences, Boston, Massachusetts, United States of America
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- * E-mail: (JBM); (DKD)
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20
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Durham ND, Howard AR, Govindan R, Senjobe F, Fels JM, Diehl WE, Luban J, Chandran K, Munro JB. Real-Time Analysis of Individual Ebola Virus Glycoproteins Reveals Pre-Fusion, Entry-Relevant Conformational Dynamics. Viruses 2020; 12:v12010103. [PMID: 31952255 PMCID: PMC7019799 DOI: 10.3390/v12010103] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 01/09/2020] [Accepted: 01/10/2020] [Indexed: 12/21/2022] Open
Abstract
The Ebola virus (EBOV) envelope glycoprotein (GP) mediates the fusion of the virion membrane with the membrane of susceptible target cells during infection. While proteolytic cleavage of GP by endosomal cathepsins and binding of the cellular receptor Niemann-Pick C1 protein (NPC1) are essential steps for virus entry, the detailed mechanisms by which these events promote membrane fusion remain unknown. Here, we applied single-molecule Förster resonance energy transfer (smFRET) imaging to investigate the structural dynamics of the EBOV GP trimeric ectodomain, and the functional transmembrane protein on the surface of pseudovirions. We show that in both contexts, pre-fusion GP is dynamic and samples multiple conformations. Removal of the glycan cap and NPC1 binding shift the conformational equilibrium, suggesting stabilization of conformations relevant to viral fusion. Furthermore, several neutralizing antibodies enrich alternative conformational states. This suggests that these antibodies neutralize EBOV by restricting access to GP conformations relevant to fusion. This work demonstrates previously unobserved dynamics of pre-fusion EBOV GP and presents a platform with heightened sensitivity to conformational changes for the study of GP function and antibody-mediated neutralization.
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Affiliation(s)
- Natasha D. Durham
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01605, USA;
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine and Sackler School of Graduate Biomedical Sciences, Boston, MA 02111, USA; (A.R.H.); (F.S.)
- Correspondence: (N.D.D.); (J.B.M.)
| | - Angela R. Howard
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine and Sackler School of Graduate Biomedical Sciences, Boston, MA 02111, USA; (A.R.H.); (F.S.)
| | - Ramesh Govindan
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01605, USA;
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine and Sackler School of Graduate Biomedical Sciences, Boston, MA 02111, USA; (A.R.H.); (F.S.)
| | - Fernando Senjobe
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine and Sackler School of Graduate Biomedical Sciences, Boston, MA 02111, USA; (A.R.H.); (F.S.)
| | - J. Maximilian Fels
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (J.M.F.); (K.C.)
| | - William E. Diehl
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA; (W.E.D.); (J.L.)
| | - Jeremy Luban
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA; (W.E.D.); (J.L.)
| | - Kartik Chandran
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (J.M.F.); (K.C.)
| | - James B. Munro
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA 01605, USA;
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine and Sackler School of Graduate Biomedical Sciences, Boston, MA 02111, USA; (A.R.H.); (F.S.)
- Correspondence: (N.D.D.); (J.B.M.)
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21
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Liu N, Girvin ME, Brenowitz M, Lai JR. Conformational and lipid bilayer-perturbing properties of Marburg virus GP2 segments containing the fusion loop and membrane-proximal external region/transmembrane domain. Heliyon 2019; 5:e03018. [PMID: 31890962 PMCID: PMC6926192 DOI: 10.1016/j.heliyon.2019.e03018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 11/04/2019] [Accepted: 12/06/2019] [Indexed: 12/13/2022] Open
Abstract
Fusion of host and viral membranes is a crucial step during infection by enveloped viruses. In the structurally-defined "class I″ viral glycoproteins, the formation of a highly stable α-helical bundle by the ectodomain of the fusion subunit (e.g., GP2 for Marburg virus, MARV) is postulated to provide the energetic driving force to overcome barriers associated with membrane fusion. Upon cell binding, the fusion subunit is proposed to form an extended intermediate that bridges both the viral and host membranes, and collapse of this extended intermediate brings the two membranes into proximity. While there is much high-resolution structural data available for prefusion and post-fusion structures of viral glycoproteins, little information is available about intermediate conformations especially in the context of the fusion loop/peptide (FL or FP) and membrane-proximal external region (MPER)/transmembrane (TM) segments. We present structural and functional studies on segments of MARV GP2 that encompass the FL and MPER/TM in detergent micelles and lipid bicelles. A protein that contains most elements of GP2 ("MGP2-full") is α-helical in membrane-mimicking environments and has pH-dependent membrane lytic activity. MGP2-full is monomeric under such conditions, contrasting with the trimeric species that has been described previously for MARV GP2 ectodomain in aqueous buffer. Variants of MARV GP2 containing the N- and C-terminal halves ("MGP2-FNL" and "MGP2-CMT", respectively) have similar properties. This work provides novel insight into conformational and membrane-perturbing properties of the MARV fusion subunit and how they may relate to viral membrane fusion.
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Affiliation(s)
- Nina Liu
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Mark E Girvin
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Michael Brenowitz
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.,Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Jonathan R Lai
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
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22
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X-ray Structures of the Post-fusion 6-Helix Bundle of the Human Syncytins and their Functional Implications. J Mol Biol 2019; 431:4922-4940. [PMID: 31711961 PMCID: PMC7094397 DOI: 10.1016/j.jmb.2019.10.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 10/22/2019] [Accepted: 10/23/2019] [Indexed: 12/27/2022]
Abstract
The retroviral envelope-derived proteins syncytin-1 and syncytin-2 (syn1 and syn2) drive placentation in humans by forming a syncytiotophoblast, a structure allowing for an exchange interface between maternal and fetal blood during pregnancy. Despite their essential role, little is known about the molecular mechanism underlying the syncytins' function. We report here the X-ray structures of the syn1 and syn2 transmembrane subunit ectodomains, featuring a 6-helix bundle (6HB) typical of the post-fusion state of gamma-retrovirus and filovirus fusion proteins. Contrary to the filoviruses, for which the fusion glycoprotein was crystallized both in the post-fusion and in the spring-loaded pre-fusion form, the highly unstable nature of the syncytins' prefusion form has precluded structural studies. We undertook a proline-scanning approach searching for regions in the syn1 6HB central helix that tolerate the introduction of helix-breaker residues and still fold correctly in the pre-fusion form. We found that there is indeed such a region, located two α-helical turns downstream a stutter in the central coiled-coil helix - precisely where the breaks of the spring-loaded helix of the filoviruses map. These mutants were fusion-inactive as they cannot form the 6HB, similar to the “SOSIP” mutant of HIV Env that allowed the high-resolution structural characterization of its labile pre-fusion form. These results now open a new window of opportunity to engineer more stable variants of the elusive pre-fusion trimer of the syncytins and other gamma-retroviruses envelope proteins for structural characterization. A typical retroviral γ-type Env protein 6-helix bundle in post-fusion syncytins. An extensive ionic interactions network correlates with higher stability of syn1. Spring-loaded pre-fusion form hinted by structural homology with filoviruses. Helix-breaking residues in the central coiled-coil allow folding in pre-fusion form.
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23
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Computer-designed orthogonal RNA aptamers programmed to recognize Ebola virus glycoproteins. BIOSAFETY AND HEALTH 2019. [DOI: 10.1016/j.bsheal.2019.11.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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24
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Cholesterol-conjugated stapled peptides inhibit Ebola and Marburg viruses in vitro and in vivo. Antiviral Res 2019; 171:104592. [PMID: 31473342 DOI: 10.1016/j.antiviral.2019.104592] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Revised: 08/22/2019] [Accepted: 08/25/2019] [Indexed: 02/07/2023]
Abstract
Filoviridae currently includes five official and one proposed genera. Genus Ebolavirus includes five established and one proposed ebolavirus species for Bombali virus (BOMV), Bundibugyo virus (BDBV), Ebola virus (EBOV), Reston virus (RESTV), Sudan virus (SUDV) and Taï Forest virus (TAFV), and genus Marburgvirus includes a single species for Marburg virus (MARV) and Ravn virus (RAVV). Ebola virus (EBOV) has emerged as a significant public health concern since the 2013-2016 Ebola Virus Disease outbreak in Western Africa. Currently, there are no therapeutics approved and the need for Ebola-specific therapeutics remains a gap. In search for anti-Ebola therapies we tested the idea of using inhibitory properties of peptides corresponding to the C-terminal heptad-repeat (HR2) domains of class I fusion proteins against EBOV infection. The fusion protein GP2 of EBOV belongs to class I, suggesting that a similar strategy to HIV may be applied to inhibit EBOV infection. The serum half-life of peptides was expanded by cholesterol conjugation to allow daily dosing. The peptides were further constrained to stabilize a helical structure to increase the potency of inhibition. The EC50s of lead peptides were in low micromolar range, as determined by a high-content imaging test of EBOV-infected cells. Lead peptides were tested in an EBOV lethal mouse model and efficacy of the peptides were determined following twice-daily administration of peptides for 9 days. The most potent peptide was able to protect mice from lethal challenge of mouse-adapted Ebola virus. These data show that engineered peptides coupled with cholesterol can inhibit viral production, protect mice against lethal EBOV infection, and may be used to build novel therapeutics against EBOV.
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25
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Developments in single-molecule and single-particle fluorescence-based approaches for studying viral envelope glycoprotein dynamics and membrane fusion. Adv Virus Res 2019; 104:123-146. [PMID: 31439147 DOI: 10.1016/bs.aivir.2019.05.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Fusion of viral and cellular membranes is an essential step in the entry pathway of all enveloped viruses. This is a dynamic and multistep process, which has been extensively studied, resulting in the endpoints of the reaction being firmly established, and many essential cellular factors identified. What remains is to elucidate the dynamic events that underlie this process, including the order and timing of glycoprotein conformational changes, receptor-binding events, and movement of the glycoprotein on the surface of the virion. Due to the inherently asynchronous nature of these dynamics, there has been an increased focus on the study of single virions and single molecules. These techniques provide researchers the high precision and resolution necessary to bridge the gaps in our understanding of viral membrane fusion. This review highlights the advancement of single-molecule and single-particle fluorescence-based techniques, with a specific focus on how these techniques have been used to study the dynamic nature of the viral fusion pathway.
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26
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Halder AK, Dutta P, Kundu M, Basu S, Nasipuri M. Review of computational methods for virus-host protein interaction prediction: a case study on novel Ebola-human interactions. Brief Funct Genomics 2019; 17:381-391. [PMID: 29028879 PMCID: PMC7109800 DOI: 10.1093/bfgp/elx026] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Identification of potential virus–host interactions is useful and vital to control the highly infectious virus-caused diseases. This may contribute toward development of new drugs to treat the viral infections. Recently, database records of clinically and experimentally validated interactions between a small set of human proteins and Ebola virus (EBOV) have been published. Using the information of the known human interaction partners of EBOV, our main objective is to identify a set of proteins that may interact with EBOV proteins. Here, we first review the state-of-the-art, computational methods used for prediction of novel virus–host interactions for infectious diseases followed by a case study on EBOV–human interactions. The assessment result shows that the predicted human host proteins are highly similar with known human interaction partners of EBOV in the context of structure and semantics and are responsible for similar biochemical activities, pathways and host–pathogen relationships.
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Affiliation(s)
- Anup Kumar Halder
- Department of Computer Science and Engineering, Jadavpur University, India
| | - Pritha Dutta
- Department of Computer Science and Engineering, Jadavpur University, India
| | - Mahantapas Kundu
- Department of Computer Science and Engineering, Jadavpur University, India
| | - Subhadip Basu
- Department of Computer Science and Engineering, Jadavpur University, India
| | - Mita Nasipuri
- Department of Computer Science and Engineering, Jadavpur University, India
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27
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King LB, West BR, Moyer CL, Gilchuk P, Flyak A, Ilinykh PA, Bombardi R, Hui S, Huang K, Bukreyev A, Crowe JE, Saphire EO. Cross-reactive neutralizing human survivor monoclonal antibody BDBV223 targets the ebolavirus stalk. Nat Commun 2019; 10:1788. [PMID: 30996276 PMCID: PMC6470140 DOI: 10.1038/s41467-019-09732-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 03/12/2019] [Indexed: 11/09/2022] Open
Abstract
Three Ebolavirus genus viruses cause lethal disease and lack targeted therapeutics: Ebola virus, Sudan virus and Bundibugyo virus. Monoclonal antibody (mAb) cocktails against the surface glycoprotein (GP) present a potential therapeutic strategy. Here we report two crystal structures of the antibody BDBV223, alone and complexed with its GP2 stalk epitope, an interesting site for therapeutic/vaccine design due to its high sequence conservation among ebolaviruses. BDBV223, identified in a human survivor of Bundibugyo virus disease, neutralizes both Bundibugyo virus and Ebola virus, but not Sudan virus. Importantly, the structure suggests that BDBV223 binding interferes with both the trimeric bundle assembly of GP and the viral membrane by stabilizing a conformation in which the monomers are separated by GP lifting or bending. Targeted mutagenesis of BDBV223 to enhance SUDV GP recognition indicates that additional determinants of antibody binding likely lie outside the visualized interactions, and perhaps involve quaternary assembly or membrane-interacting regions. Human antibodies cross-reactive for several viruses within the Ebolavirus genus have been identified. Here the authors present the crystal structure of such a neutralizing monoclonal antibody (mAb) targeting the stalk of Bundibugyo virus glycoprotein and show that mAb binding may interfere with trimeric bundle assembly and/or the viral membrane.
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Affiliation(s)
- Liam B King
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Brandyn R West
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Crystal L Moyer
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Pavlo Gilchuk
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Andrew Flyak
- Departments of Pediatrics, Pathology, and Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Philipp A Ilinykh
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, 77555, USA.,Galveston National Laboratory, Galveston, TX, 77555, USA
| | - Robin Bombardi
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Sean Hui
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Kai Huang
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, 77555, USA.,Galveston National Laboratory, Galveston, TX, 77555, USA
| | - Alexander Bukreyev
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, 77555, USA.,Galveston National Laboratory, Galveston, TX, 77555, USA.,Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - James E Crowe
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, 37232, USA.,Departments of Pediatrics, Pathology, and Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Erica Ollmann Saphire
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, 92037, USA. .,Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA. .,La Jolla Institute for Immunology La Jolla, CA, 92037, USA.
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28
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Antibody responses to viral infections: a structural perspective across three different enveloped viruses. Nat Microbiol 2019; 4:734-747. [PMID: 30886356 PMCID: PMC6818971 DOI: 10.1038/s41564-019-0392-y] [Citation(s) in RCA: 125] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 01/29/2019] [Indexed: 02/07/2023]
Abstract
Antibodies serve as critical barriers to viral infection. Humoral immunity to a virus is achieved through the dual role of antibodies in communicating the presence of invading pathogens in infected cells to effector cells and interfering with processes essential to the viral lifecycle, chiefly entry into the host cell. For individuals that successfully control infection, virus-elicited antibodies can provide lifelong surveillance and protection from future insults. One approach to understand the nature of a successful immune response has been to utilize structural biology to uncover the molecular details of the antibodies derived from vaccines or natural infection and how they interact with their cognate microbial antigens. The ability to isolate antigen specific B-cells and rapidly solve structures of functional, monoclonal antibodies in complex with viral glycoprotein surface antigens has greatly expanded our knowledge of the sites of vulnerability on viruses. In this review, we compare the adaptive humoral immune responses to HIV, influenza, and filoviruses, with a particular focus on neutralizing antibodies. The pathogenesis of each of these viruses is quite different, providing an opportunity for comparison of immune responses: HIV causes a persistent, chronic infection; influenza an acute infection with multiple exposures during a lifetime and annual vaccination; and filoviruses, a virulent, acute infection. Neutralizing antibodies that develop under these different constraints are therefore sentinels that can provide insight into the underlying humoral immune responses and important lessons to guide future development of vaccines and immunotherapeutics.
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29
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King LB, Milligan JC, West BR, Schendel SL, Ollmann Saphire E. Achieving cross-reactivity with pan-ebolavirus antibodies. Curr Opin Virol 2019; 34:140-148. [PMID: 30884329 DOI: 10.1016/j.coviro.2019.01.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 01/24/2019] [Indexed: 11/25/2022]
Abstract
Filoviruses are the causative agents of highly lethal outbreaks in sub-Saharan Africa. Although an experimental vaccine and several therapeutics are being deployed in the Democratic Republic of Congo to combat the ongoing Ebola virus outbreak, these therapies are specific for only one filovirus species. There is currently significant interest in developing broadly reactive monoclonal antibodies (mAbs) with utility against the variety of ebolaviruses that may emerge. Thus far, the primary target of these mAbs has been the viral spike glycoprotein (GP). Here we present an overview of GP-targeted antibodies that exhibit broad reactivity and the structural characteristics that could confer this cross-reactivity. We also discuss how these structural features could be leveraged to design vaccine antigens that elicit cross-reactive antibodies.
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Affiliation(s)
- Liam B King
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Jacob C Milligan
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Brandyn R West
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Sharon L Schendel
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Erica Ollmann Saphire
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA; Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
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30
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Structural basis of broad ebolavirus neutralization by a human survivor antibody. Nat Struct Mol Biol 2019; 26:204-212. [PMID: 30833785 PMCID: PMC6402988 DOI: 10.1038/s41594-019-0191-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 01/23/2019] [Indexed: 11/08/2022]
Abstract
The structural features that govern broad-spectrum activity of broadly neutralizing, anti-ebolavirus antibodies (Abs) outside of the internal fusion loop epitope are currently unknown. Here we describe the structure of a broadly neutralizing human monoclonal Ab (mAb), ADI-15946, which was identified in a human survivor of the 2013–2016 outbreak. The crystal structure of ADI-15946 in complex with cleaved Ebola virus glycoprotein (EBOV GPCL) reveals that binding of the mAb structurally mimics the conserved interaction between the EBOV GP core and its glycan cap β17-β18 loop to inhibit infection. Both endosomal proteolysis of EBOV GP and binding of mAb FVM09 displace this loop, thereby increasing exposure of ADI-15946’s conserved epitope and enhancing neutralization. Our work also mapped the paratope of ADI-15946 thereby explaining reduced activity against Sudan virus (SUDV), which enabled rational, structure-guided engineering to enhance binding and neutralization against SUDV while retaining the parental activity against EBOV and Bundibugyo virus (BDBV).
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31
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Jain S, Baranwal M. Computational analysis in designing T cell epitopes enriched peptides of Ebola glycoprotein exhibiting strong binding interaction with HLA molecules. J Theor Biol 2019; 465:34-44. [DOI: 10.1016/j.jtbi.2019.01.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 12/28/2018] [Accepted: 01/09/2019] [Indexed: 01/13/2023]
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32
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A viral-fusion-peptide-like molecular switch drives membrane insertion of botulinum neurotoxin A1. Nat Commun 2018; 9:5367. [PMID: 30560862 PMCID: PMC6299077 DOI: 10.1038/s41467-018-07789-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 11/22/2018] [Indexed: 11/09/2022] Open
Abstract
Botulinum neurotoxin (BoNT) delivers its protease domain across the vesicle membrane to enter the neuronal cytosol upon vesicle acidification. This process is mediated by its translocation domain (HN), but the molecular mechanism underlying membrane insertion of HN remains poorly understood. Here, we report two crystal structures of BoNT/A1 HN that reveal a novel molecular switch (termed BoNT-switch) in HN, where buried α-helices transform into surface-exposed hydrophobic β-hairpins triggered by acidic pH. Locking the BoNT-switch by disulfide trapping inhibited the association of HN with anionic liposomes, blocked channel formation by HN, and reduced the neurotoxicity of BoNT/A1 by up to ~180-fold. Single particle counting studies showed that an acidic environment tends to promote BoNT/A1 self-association on liposomes, which is partly regulated by the BoNT-switch. These findings suggest that the BoNT-switch flips out upon exposure to the acidic endosomal pH, which enables membrane insertion of HN that subsequently leads to LC delivery. The translocation domain (HN) of Botulinum neurotoxins (BoNTs) mediates the delivery of the BoNT light chain (LC) into neuronal cytosol. Here the authors provide insights into HN membrane insertion by determining the crystal structure of BoNT/A1 HN at acidic pH, which reveals a molecular switch in HN, where buried α-helices are transformed into surface-exposed hydrophobic β-hairpins.
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33
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Structural basis for broad neutralization of ebolaviruses by an antibody targeting the glycoprotein fusion loop. Nat Commun 2018; 9:3934. [PMID: 30258051 PMCID: PMC6158212 DOI: 10.1038/s41467-018-06113-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 08/17/2018] [Indexed: 11/09/2022] Open
Abstract
The severity of the 2014-2016 ebolavirus outbreak in West Africa expedited clinical development of therapeutics and vaccines though the countermeasures on hand were largely monospecific and lacked efficacy against other ebolavirus species that previously emerged. Recent studies indicate that ebolavirus glycoprotein (GP) fusion loops are targets for cross-protective antibodies. Here we report the 3.72 Å resolution crystal structure of one such cross-protective antibody, CA45, bound to the ectodomain of Ebola virus (EBOV) GP. The CA45 epitope spans multiple faces of the fusion loop stem, across both GP1 and GP2 subunits, with ~68% of residues identical across > 99.5% of known ebolavirus isolates. Extensive antibody interactions within a pan-ebolavirus small-molecule inhibitor binding cavity on GP define this cavity as a novel site of immune vulnerability. The structure elucidates broad ebolavirus neutralization through a highly conserved epitope on GP and further enables rational design and development of broadly protective vaccines and therapeutics.
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34
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West BR, Moyer CL, King LB, Fusco ML, Milligan JC, Hui S, Saphire EO. Structural Basis of Pan-Ebolavirus Neutralization by a Human Antibody against a Conserved, yet Cryptic Epitope. mBio 2018; 9:e01674-18. [PMID: 30206174 PMCID: PMC6134094 DOI: 10.1128/mbio.01674-18] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 08/09/2018] [Indexed: 01/02/2023] Open
Abstract
Only one naturally occurring human antibody has been described thus far that is capable of potently neutralizing all five ebolaviruses. Here we present two crystal structures of this rare, pan-ebolavirus neutralizing human antibody in complex with Ebola virus and Bundibugyo virus glycoproteins (GPs), respectively. The structures delineate the key protein and glycan contacts for binding that are conserved across the ebolaviruses, explain the antibody's unique broad specificity and neutralization activity, and reveal the likely mechanism behind a known escape mutation in the fusion loop region of GP2. We found that the epitope of this antibody, ADI-15878, extends along the hydrophobic paddle of the fusion loop and then dips down into a highly conserved pocket beneath the N-terminal tail of GP2, a mode of recognition unlike any other antibody elicited against Ebola virus, and likely critical for its broad activity. The fold of Bundibugyo virus glycoprotein, not previously visualized, is similar to the fold of Ebola virus GP, and ADI-15878 binds to each virus's GP with a similar strategy and angle of attack. These findings will be useful in deployment of this antibody as a broad-spectrum therapeutic and in the design of immunogens that elicit the desired broadly neutralizing immune response against all members of the ebolavirus genus and filovirus family.IMPORTANCE There are five different members of the Ebolavirus genus. Provision of vaccines and treatments able to protect against any of the five ebolaviruses is an important goal of public health. Antibodies are a desired result of vaccines and can be delivered directly as therapeutics. Most antibodies, however, are effective against only one or two, not all, of these pathogens. Only one human antibody has been thus far described to neutralize all five ebolaviruses, antibody ADI-15878. Here we describe the molecular structure of ADI-15878 bound to the relevant target proteins of Ebola virus and Bundibugyo virus. We explain how it achieves its rare breadth of activity and propose strategies to design improved vaccines capable of eliciting more antibodies like ADI-15878.
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Affiliation(s)
- Brandyn R West
- Department of Immunology and Microbiology, Scripps Research, La Jolla, California, USA
| | - Crystal L Moyer
- Department of Immunology and Microbiology, Scripps Research, La Jolla, California, USA
| | - Liam B King
- Department of Immunology and Microbiology, Scripps Research, La Jolla, California, USA
| | - Marnie L Fusco
- Department of Immunology and Microbiology, Scripps Research, La Jolla, California, USA
| | - Jacob C Milligan
- Department of Immunology and Microbiology, Scripps Research, La Jolla, California, USA
| | - Sean Hui
- Department of Immunology and Microbiology, Scripps Research, La Jolla, California, USA
| | - Erica Ollmann Saphire
- Department of Immunology and Microbiology, Scripps Research, La Jolla, California, USA
- Skaggs Institute for Chemical Biology, Scripps Research, La Jolla, California, USA
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35
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The structural basis for filovirus neutralization by monoclonal antibodies. Curr Opin Immunol 2018; 53:196-202. [PMID: 29940415 DOI: 10.1016/j.coi.2018.05.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Revised: 04/30/2018] [Accepted: 05/02/2018] [Indexed: 12/21/2022]
Abstract
Filoviruses, including ebolaviruses and marburgviruses, are the causative agents of highly lethal disease outbreaks. The 2013-2016 Ebola virus outbreak was responsible for >28000 infections and >11000 deaths. Although there are currently no licensed vaccines or therapeutics for any filovirus-induced disease, monoclonal antibodies (mAbs) are among the most promising options for therapeutic development. Hundreds of mAbs have been isolated from human survivors of filovirus infections that target the viral spike glycoprotein (GP). The binding, neutralization, and cross-reactivity of many of these mAbs has been determined. Several mAbs have been characterized structurally, and this information has been crucial for strategizing therapeutic and vaccine design. Here we present an overview of the structural features of the neutralizing/protective epitopes on filovirus glycoproteins.
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36
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Structural Transition and Antibody Binding of EBOV GP and ZIKV E Proteins from Pre-Fusion to Fusion-Initiation State. Biomolecules 2018; 8:biom8020025. [PMID: 29748487 PMCID: PMC6022868 DOI: 10.3390/biom8020025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 05/04/2018] [Accepted: 05/07/2018] [Indexed: 11/17/2022] Open
Abstract
Membrane fusion proteins are responsible for viral entry into host cells—a crucial first step in viral infection. These proteins undergo large conformational changes from pre-fusion to fusion-initiation structures, and, despite differences in viral genomes and disease etiology, many fusion proteins are arranged as trimers. Structural information for both pre-fusion and fusion-initiation states is critical for understanding virus neutralization by the host immune system. In the case of Ebola virus glycoprotein (EBOV GP) and Zika virus envelope protein (ZIKV E), pre-fusion state structures have been identified experimentally, but only partial structures of fusion-initiation states have been described. While the fusion-initiation structure is in an energetically unfavorable state that is difficult to solve experimentally, the existing structural information combined with computational approaches enabled the modeling of fusion-initiation state structures of both proteins. These structural models provide an improved understanding of four different neutralizing antibodies in the prevention of viral host entry.
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37
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Zhao Y, Ren J, Fry EE, Xiao J, Townsend AR, Stuart DI. Structures of Ebola Virus Glycoprotein Complexes with Tricyclic Antidepressant and Antipsychotic Drugs. J Med Chem 2018; 61:4938-4945. [DOI: 10.1021/acs.jmedchem.8b00350] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Yuguang Zhao
- Division of Structural Biology, University of Oxford, The Henry Wellcome Building for Genomic Medicine, Headington, Oxford OX3 7BN, U.K
| | - Jingshan Ren
- Division of Structural Biology, University of Oxford, The Henry Wellcome Building for Genomic Medicine, Headington, Oxford OX3 7BN, U.K
| | - Elizabeth E. Fry
- Division of Structural Biology, University of Oxford, The Henry Wellcome Building for Genomic Medicine, Headington, Oxford OX3 7BN, U.K
| | - Julia Xiao
- Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, U.K
| | - Alain R. Townsend
- Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, U.K
| | - David I. Stuart
- Division of Structural Biology, University of Oxford, The Henry Wellcome Building for Genomic Medicine, Headington, Oxford OX3 7BN, U.K
- Diamond Light Source Ltd, Harwell Science & Innovation Campus, Didcot OX11 0DE, U.K
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38
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Flyak AI, Kuzmina N, Murin CD, Bryan C, Davidson E, Gilchuk P, Gulka CP, Ilinykh PA, Shen X, Huang K, Ramanathan P, Turner H, Fusco ML, Lampley R, Kose N, King H, Sapparapu G, Doranz BJ, Ksiazek TG, Wright DW, Saphire EO, Ward AB, Bukreyev A, Crowe JE. Broadly neutralizing antibodies from human survivors target a conserved site in the Ebola virus glycoprotein HR2-MPER region. Nat Microbiol 2018; 3:670-677. [PMID: 29736037 PMCID: PMC6030461 DOI: 10.1038/s41564-018-0157-z] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 04/06/2018] [Indexed: 12/13/2022]
Abstract
Ebola virus (EBOV) in humans causes a severe illness with high mortality rates. Several strategies have been developed in the past to treat EBOV infection, including the antibody cocktail ZMappTM that has been shown to be effective in nonhuman primate models of infection1 and has been used under compassionate-treatment protocols in humans2. ZMappTM is a mixture of three chimerized murine monoclonal antibodies (mAbs)3–6 that target EBOV-specific epitopes on the surface glycoprotein (GP)7,8. However, ZMappTM mAbs do not neutralize other species from the Ebolavirus genus, such as Bundibugyo virus (BDBV), Reston virus (RESTV) or Sudan virus (SUDV). Here we describe three naturally-occurring human cross-neutralizing mAbs, from BDBV survivors, that target an antigenic site in the canonical heptad repeat 2 (HR2) region near the membrane proximal external region (MPER) of GP. The identification of a conserved neutralizing antigenic site in the GP suggests that these mAbs could be used to design universal antibody therapeutics against diverse ebolavirus species. Furthermore, we found that immunization with a peptide comprising the HR2/MPER antigenic site elicits neutralizing antibodies in rabbits. Structural features determined by conserved residues in the antigenic site described here could inform an epitope-based vaccine design against infection caused by diverse ebolavirus species.
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Affiliation(s)
- Andrew I Flyak
- Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, TN, USA.,Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Natalia Kuzmina
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA.,Galveston National Laboratory, Galveston, TX, USA
| | - Charles D Murin
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, USA.,Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA, USA
| | | | | | - Pavlo Gilchuk
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Christopher P Gulka
- Department of Chemistry, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Philipp A Ilinykh
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA.,Galveston National Laboratory, Galveston, TX, USA
| | - Xiaoli Shen
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA.,Galveston National Laboratory, Galveston, TX, USA
| | - Kai Huang
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA.,Galveston National Laboratory, Galveston, TX, USA
| | - Palaniappan Ramanathan
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA.,Galveston National Laboratory, Galveston, TX, USA
| | - Hannah Turner
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Marnie L Fusco
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA, USA
| | - Rebecca Lampley
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Nurgun Kose
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Hannah King
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Gopal Sapparapu
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | | | - Thomas G Ksiazek
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA.,Galveston National Laboratory, Galveston, TX, USA
| | - David W Wright
- Department of Chemistry, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Erica Ollmann Saphire
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA, USA.,The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Andrew B Ward
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Alexander Bukreyev
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA. .,Galveston National Laboratory, Galveston, TX, USA. .,Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, TX, USA.
| | - James E Crowe
- Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, TN, USA. .,Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, USA. .,Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA.
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39
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Li Q, Ma L, Yi D, Wang H, Wang J, Zhang Y, Guo Y, Li X, Zhou J, Shi Y, Gao GF, Cen S. Novel cyclo-peptides inhibit Ebola pseudotyped virus entry by targeting primed GP protein. Antiviral Res 2018; 155:1-11. [PMID: 29709562 DOI: 10.1016/j.antiviral.2018.04.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 04/24/2018] [Accepted: 04/26/2018] [Indexed: 12/19/2022]
Abstract
Ebola virus (EBOV) causes fatal hemorrhagic fever with high death rates in human. Currently, there are no available clinically-approved prophylactic or therapeutic treatments. The recently solved crystal structure of cleavage-primed EBOV glycoprotein (GPcl) in complex with the C domain of endosomal protein Niemann-Pick C1 (NPC1) provides a new target for the development of EBOV entry inhibitors. In this work, a computational approach using docking and molecular dynamic simulations is carried out for the rational design of peptide inhibitors. A novel cyclo-peptide (Pep-3.3) was identified to target at the late stage of EBOV entry and exhibit specific inhibitory activity against EBOV-GP pseudotyped viruses, with 50% inhibitory concentration (IC50) of 5.1 μM. In vitro binding assay and molecular simulations revealed that Pep-3.3 binds to GPcl with a KD value of 69.7 μM, through interacting with predicted residues in the hydrophobic binding pocket of GPcl. Mutation of predicted residues T83 caused resistance to Pep-3.3 inhibition in viral infectivity, providing preliminary support for the model of the peptide binding to GPcl. This study demonstrates the feasibility of inhibiting EBOV entry by targeting GPcl with peptides.
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Affiliation(s)
- Quanjie Li
- Department of Immunology, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Beijing 100050, China
| | - Ling Ma
- Department of Immunology, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Beijing 100050, China
| | - Dongrong Yi
- Department of Immunology, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Beijing 100050, China
| | - Han Wang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Jing Wang
- Department of Immunology, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Beijing 100050, China
| | - Yongxin Zhang
- Department of Immunology, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Beijing 100050, China
| | - Ying Guo
- Institute of Materia Medica, Chinese Academy of Medical Sciences, Beijing 100050, China
| | - Xiaoyu Li
- Department of Immunology, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Beijing 100050, China
| | - Jinming Zhou
- Department of Immunology, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Beijing 100050, China.
| | - Yi Shi
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - George F Gao
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shan Cen
- Department of Immunology, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Beijing 100050, China.
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40
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Abou-Hamdan A, Belot L, Albertini A, Gaudin Y. Monomeric Intermediates Formed by Vesiculovirus Glycoprotein during Its Low-pH-induced Structural Transition. J Mol Biol 2018; 430:1685-1695. [PMID: 29678555 PMCID: PMC7126088 DOI: 10.1016/j.jmb.2018.04.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 04/06/2018] [Accepted: 04/10/2018] [Indexed: 01/26/2023]
Abstract
Vesiculovirus G is the prototype of class III viral fusion glycoproteins. The structures of both G pre- and post-fusion conformation have been determined. The structure of monomeric intermediates reveals the pathway of the transition. A fusion-loop-exposing antiparallel dimer may initiate the fusion process. Those data challenge the current model proposed for viral membrane fusion.
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Affiliation(s)
- Abbas Abou-Hamdan
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette cedex, France
| | - Laura Belot
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette cedex, France
| | - Aurélie Albertini
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette cedex, France
| | - Yves Gaudin
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette cedex, France.
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41
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Abstract
The Filoviridae are a family of negative-strand RNA viruses that include several important human pathogens. Ebola virus (EBOV) and Marburg virus are well-known filoviruses which cause life-threatening viral hemorrhagic fever in human and nonhuman primates. In addition to severe pathogenesis, filoviruses also exhibit a propensity for human-to-human transmission by close contact, posing challenges to containment and crisis management. Past outbreaks, in particular the recent West African EBOV epidemic, have been responsible for thousands of deaths and vaulted the filoviruses into public consciousness. Both national and international health agencies continue to regard potential filovirus outbreaks as critical threats to global public health. To develop effective countermeasures, a basic understanding of filovirus biology is needed. This review encompasses the epidemiology, ecology, molecular biology, and evolution of the filoviruses.
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Affiliation(s)
- Jackson Emanuel
- Laboratory of Virology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, United States
| | - Andrea Marzi
- Laboratory of Virology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, United States
| | - Heinz Feldmann
- Laboratory of Virology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, United States.
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42
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Ren J, Zhao Y, Fry EE, Stuart DI. Target Identification and Mode of Action of Four Chemically Divergent Drugs against Ebolavirus Infection. J Med Chem 2018; 61:724-733. [PMID: 29272110 PMCID: PMC5808380 DOI: 10.1021/acs.jmedchem.7b01249] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Here, we show that four chemically divergent approved drugs reported to inhibit Ebolavirus infection, benztropine, bepridil, paroxetine and sertraline, directly interact with the Ebolavirus glycoprotein. Binding of these drugs destabilizes the protein, suggesting that this may be the mechanism of inhibition, as reported for the anticancer drug toremifene and the painkiller ibuprofen, which bind in the same large cavity on the glycoprotein. Crystal structures show that the position of binding and the mode of interaction within the pocket vary significantly between these compounds. The binding constants (Kd) determined by thermal shift assay correlate with the protein-inhibitor interactions as well as with the antiviral activities determined by virus cell entry assays, supporting the hypothesis that these drugs inhibit viral entry by binding the glycoprotein and destabilizing the prefusion conformation. Details of the protein-inhibitor interactions of these complexes and their relation with binding affinity may facilitate the design of more potent inhibitors.
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Affiliation(s)
- Jingshan Ren
- Division of Structural Biology, University of Oxford , The Henry Wellcome Building for Genomic Medicine, Headington, Oxford, OX3 7BN, U.K
| | - Yuguang Zhao
- Division of Structural Biology, University of Oxford , The Henry Wellcome Building for Genomic Medicine, Headington, Oxford, OX3 7BN, U.K
| | - Elizabeth E Fry
- Division of Structural Biology, University of Oxford , The Henry Wellcome Building for Genomic Medicine, Headington, Oxford, OX3 7BN, U.K
| | - David I Stuart
- Division of Structural Biology, University of Oxford , The Henry Wellcome Building for Genomic Medicine, Headington, Oxford, OX3 7BN, U.K.,Diamond Light Source Ltd. , Harwell Science & Innovation Campus, Didcot, OX11 0DE, U.K
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43
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Proteolytic Processing of Filovirus Glycoproteins. ACTIVATION OF VIRUSES BY HOST PROTEASES 2018. [PMCID: PMC7122482 DOI: 10.1007/978-3-319-75474-1_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Filoviruses (Marburg virus and Ebola virus) have a single envelope glycoprotein (GP) that initiates infection. GP is a class I fusion protein that forms trimeric spikes composed of heterodimers of the subunits GP1 and GP2. GP1 and GP2 are derived from the precursor pre-GP by furin cleavage during exocytosis. GP1 contains a receptor-binding core topped by a glycan cap and a heavily glycosylated mucin-like domain, while GP2 contains a fusion loop and a membrane anchor. After entering cells by macropinocytosis, the glycan cap and the mucin-like domain are removed from GP1 by endosomal cathepsins B and L exposing the binding site for the Niemann-Pick C1 receptor. It appears that there is no strict requirement for specific proteases involved in GP processing. Thus, furin is not indispensible for GP1-2 cleavage, and GP1 may be trimmed not only by cathepsins B and L but also by other endosomal proteases. Two soluble glycoproteins of Ebola virus are also processed by host proteases. A significant amount of GP1,2 is cleaved by the metalloprotease TACE and shed from the surface of infected cells (GP1,2 delta). The secreted protein sGP is derived from the precursor pre-sGP by furin cleavage.
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44
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Tectonic conformational changes of a coronavirus spike glycoprotein promote membrane fusion. Proc Natl Acad Sci U S A 2017; 114:11157-11162. [PMID: 29073020 DOI: 10.1073/pnas.1708727114] [Citation(s) in RCA: 404] [Impact Index Per Article: 57.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The tremendous pandemic potential of coronaviruses was demonstrated twice in the past few decades by two global outbreaks of deadly pneumonia. The coronavirus spike (S) glycoprotein initiates infection by promoting fusion of the viral and cellular membranes through conformational changes that remain largely uncharacterized. Here we report the cryoEM structure of a coronavirus S glycoprotein in the postfusion state, showing large-scale secondary, tertiary, and quaternary rearrangements compared with the prefusion trimer and rationalizing the free-energy landscape of this conformational machine. We also biochemically characterized the molecular events associated with refolding of the metastable prefusion S glycoprotein to the postfusion conformation using limited proteolysis, mass spectrometry, and single-particle EM. The observed similarity between postfusion coronavirus S and paramyxovirus F structures demonstrates that a conserved refolding trajectory mediates entry of these viruses and supports the evolutionary relatedness of their fusion subunits. Finally, our data provide a structural framework for understanding the mode of neutralization of antibodies targeting the fusion machinery and for engineering next-generation subunit vaccines or inhibitors against this medically important virus family.
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45
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Structure of the Ebola virus envelope protein MPER/TM domain and its interaction with the fusion loop explains their fusion activity. Proc Natl Acad Sci U S A 2017; 114:E7987-E7996. [PMID: 28874543 DOI: 10.1073/pnas.1708052114] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Ebolavirus (EBOV), an enveloped filamentous RNA virus causing severe hemorrhagic fever, enters cells by macropinocytosis and membrane fusion in a late endosomal compartment. Fusion is mediated by the EBOV envelope glycoprotein GP, which consists of subunits GP1 and GP2. GP1 binds to cellular receptors, including Niemann-Pick C1 (NPC1) protein, and GP2 is responsible for low pH-induced membrane fusion. Proteolytic cleavage and NPC1 binding at endosomal pH lead to conformational rearrangements of GP2 that include exposing the hydrophobic fusion loop (FL) for insertion into the cellular target membrane and forming a six-helix bundle structure. Although major portions of the GP2 structure have been solved in pre- and postfusion states and although current models place the transmembrane (TM) and FL domains of GP2 in close proximity at critical steps of membrane fusion, their structures in membrane environments, and especially interactions between them, have not yet been characterized. Here, we present the structure of the membrane proximal external region (MPER) connected to the TM domain: i.e., the missing parts of the EBOV GP2 structure. The structure, solved by solution NMR and EPR spectroscopy in membrane-mimetic environments, consists of a helix-turn-helix architecture that is independent of pH. Moreover, the MPER region is shown to interact in the membrane interface with the previously determined structure of the EBOV FL through several critical aromatic residues. Mutation of aromatic and neighboring residues in both binding partners decreases fusion and viral entry, highlighting the functional importance of the MPER/TM-FL interaction in EBOV entry and fusion.
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46
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Dutta P, Halder AK, Basu S, Kundu M. A survey on Ebola genome and current trends in computational research on the Ebola virus. Brief Funct Genomics 2017; 17:374-380. [DOI: 10.1093/bfgp/elx020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
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47
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Banadyga L, Hoenen T, Ambroggio X, Dunham E, Groseth A, Ebihara H. Ebola virus VP24 interacts with NP to facilitate nucleocapsid assembly and genome packaging. Sci Rep 2017; 7:7698. [PMID: 28794491 PMCID: PMC5550494 DOI: 10.1038/s41598-017-08167-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 07/06/2017] [Indexed: 02/03/2023] Open
Abstract
Ebola virus causes devastating hemorrhagic fever outbreaks for which no approved therapeutic exists. The viral nucleocapsid, which is minimally composed of the proteins NP, VP35, and VP24, represents an attractive target for drug development; however, the molecular determinants that govern the interactions and functions of these three proteins are still unknown. Through a series of mutational analyses, in combination with biochemical and bioinformatics approaches, we identified a region on VP24 that was critical for its interaction with NP. Importantly, we demonstrated that the interaction between VP24 and NP was required for both nucleocapsid assembly and genome packaging. Not only does this study underscore the critical role that these proteins play in the viral replication cycle, but it also identifies a key interaction interface on VP24 that may serve as a novel target for antiviral therapeutic intervention.
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Affiliation(s)
- Logan Banadyga
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, 59840, USA
| | - Thomas Hoenen
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, 59840, USA.,Friedrich-Loeffler-Institut, Greifswald, Insel Riems, Germany
| | - Xavier Ambroggio
- Bioinformatics and Computational Biosciences Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.,Rosetta Design Group, Burlington, VT, 05401, USA
| | - Eric Dunham
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, 59840, USA
| | - Allison Groseth
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, 59840, USA.,Friedrich-Loeffler-Institut, Greifswald, Insel Riems, Germany
| | - Hideki Ebihara
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, 59840, USA. .,Department of Molecular Medicine, Mayo Clinic, Rochester, MN, 55905, USA.
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48
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Vavra KC, Xia Y, Rock RS. Competition between Coiled-Coil Structures and the Impact on Myosin-10 Bundle Selection. Biophys J 2017; 110:2517-2527. [PMID: 27276269 DOI: 10.1016/j.bpj.2016.04.048] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 04/28/2016] [Accepted: 04/29/2016] [Indexed: 12/27/2022] Open
Abstract
Coiled-coil fusions are a useful approach to enforce dimerization in protein engineering. However, the final structures of coiled-coil fusion proteins have received relatively little attention. Here, we determine the structural outcome of adjacent parallel and antiparallel coiled coils. The targets are coiled coils that stabilize myosin-10 in single-molecule biophysical studies. We reveal the solution structure of a short, antiparallel, myosin-10 coiled-coil fused to the parallel GCN4-p1 coiled coil. Surprisingly, this structure is a continuous, antiparallel coiled coil where GCN4-p1 pairs with myosin-10 rather than itself. We also show that longer myosin-10 segments in these parallel/antiparallel fusions are dynamic and do not fold cooperatively. Our data resolve conflicting results on myosin-10 selection of actin filament bundles, demonstrating the importance of understanding coiled-coil orientation and stability.
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Affiliation(s)
- Kevin C Vavra
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, Illinois
| | - Youlin Xia
- Minnesota NMR Center, University of Minnesota, Minneapolis, Minnesota
| | - Ronald S Rock
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, Illinois.
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49
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Yu DS, Weng TH, Wu XX, Wang FXC, Lu XY, Wu HB, Wu NP, Li LJ, Yao HP. The lifecycle of the Ebola virus in host cells. Oncotarget 2017; 8:55750-55759. [PMID: 28903457 PMCID: PMC5589696 DOI: 10.18632/oncotarget.18498] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 05/29/2017] [Indexed: 01/01/2023] Open
Abstract
Ebola haemorrhagic fever causes deadly disease in humans and non-human primates resulting from infection with the Ebola virus (EBOV) genus of the family Filoviridae. However, the mechanisms of EBOV lifecycle in host cells, including viral entry, membrane fusion, RNP formation, GP-tetherin interaction, and VP40-inner leaflet association remain poorly understood. This review describes the biological functions of EBOV proteins and their roles in the lifecycle, summarizes the factors related to EBOV proteins or RNA expression throughout the different phases, and reviews advances with regards to the molecular events and mechanisms of the EBOV lifecycle. Furthermore, the review outlines the aspects remain unclear that urgently need to be solved in future research.
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Affiliation(s)
- Dong-Shan Yu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Tian-Hao Weng
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Xiao-Xin Wu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Frederick X C Wang
- Department of Bioengineering, Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, Dallas, TX, USA
| | - Xiang-Yun Lu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Hai-Bo Wu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Nan-Ping Wu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Lan-Juan Li
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
| | - Hang-Ping Yao
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou, China
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50
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A Polymorphism within the Internal Fusion Loop of the Ebola Virus Glycoprotein Modulates Host Cell Entry. J Virol 2017; 91:JVI.00177-17. [PMID: 28228590 DOI: 10.1128/jvi.00177-17] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 02/15/2017] [Indexed: 12/12/2022] Open
Abstract
The large scale of the Ebola virus disease (EVD) outbreak in West Africa in 2013-2016 raised the question whether the host cell interactions of the responsible Ebola virus (EBOV) strain differed from those of other ebolaviruses. We previously reported that the glycoprotein (GP) of the virus circulating in West Africa in 2014 (EBOV2014) exhibited reduced ability to mediate entry into two nonhuman primate (NHP)-derived cell lines relative to the GP of EBOV1976. Here, we investigated the molecular determinants underlying the differential entry efficiency. We found that EBOV2014-GP-driven entry into diverse NHP-derived cell lines, as well as human monocyte-derived macrophages and dendritic cells, was reduced compared to EBOV1976-GP, although entry into most human- and all bat-derived cell lines tested was comparable. Moreover, EBOV2014 replication in NHP but not human cells was diminished relative to EBOV1976, suggesting that reduced cell entry translated into reduced viral spread. Mutagenic analysis of EBOV2014-GP and EBOV1976-GP revealed that an amino acid polymorphism in the receptor-binding domain, A82V, modulated entry efficiency in a cell line-independent manner and did not account for the reduced EBOV2014-GP-driven entry into NHP cells. In contrast, polymorphism T544I, located in the internal fusion loop in the GP2 subunit, was found to be responsible for the entry phenotype. These results suggest that position 544 is an important determinant of EBOV infectivity for both NHP and certain human target cells.IMPORTANCE The Ebola virus disease outbreak in West Africa in 2013 entailed more than 10,000 deaths. The scale of the outbreak and its dramatic impact on human health raised the question whether the responsible virus was particularly adept at infecting human cells. Our study shows that an amino acid exchange, A82V, that was acquired during the epidemic and that was not observed in previously circulating viruses, increases viral entry into diverse target cells. In contrast, the epidemic virus showed a reduced ability to enter cells of nonhuman primates compared to the virus circulating in 1976, and a single amino acid exchange in the internal fusion loop of the viral glycoprotein was found to account for this phenotype.
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