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Bestle D, Bittel L, Werner AD, Kämper L, Dolnik O, Krähling V, Steinmetzer T, Böttcher-Friebertshäuser E. Novel proteolytic activation of Ebolavirus glycoprotein GP by TMPRSS2 and cathepsin L at an uncharted position can compensate for furin cleavage. Virus Res 2024; 347:199430. [PMID: 38964470 PMCID: PMC11294727 DOI: 10.1016/j.virusres.2024.199430] [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: 03/19/2024] [Revised: 05/24/2024] [Accepted: 07/01/2024] [Indexed: 07/06/2024]
Abstract
A multistep priming process involving furin and endosomal cathepsin B and L (CatB/L) has been described for the Orthoebolavirus zairense (EBOV) glycoprotein GP. Inhibition or knockdown of either furin or endosomal cathepsins, however, did not prevent virus multiplication in cell cultures. Moreover, an EBOV mutant lacking the furin cleavage motif (RRTRR→AGTAA) was able to replicate and cause fatal disease in nonhuman primates, indicating that furin cleavage may be dispensable for virus infectivity. Here, by using protease inhibitors and EBOV GP-carrying recombinant vesicular stomatitis virus (VSV) and transcription and replication-competent virus-like particles (trVLPs) we found that processing of EBOV GP is mediated by different proteases in different cell lines depending on the protease repertoire available. Endosomal cathepsins were essential for EBOV GP entry in Huh-7 but not in Vero cells, in which trypsin-like proteases and stably expressed trypsin-like transmembrane serine protease 2 (TMPRSS2) supported wild-type EBOV GP and EBOV GP_AGTAA mutant entry. Furthermore, we show that the EBOV GP_AGTAA mutant is cleaved into fusion-competent GP2 by TMPRSS2 and by CatL at a so far unknown site. Fluorescence microscopy co-localization studies indicate that EBOV GP cleavage by TMPRSS2 may occur in the TGN prior to virus release or in the late endosome at the stage of virus entry into a new cell. Our data show that EBOV GP must be proteolytically activated to support virus entry but has even greater flexibility in terms of proteases and the precise cleavage site than previously assumed.
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Affiliation(s)
- Dorothea Bestle
- Institute of Virology, Philipps-University, Marburg, Germany
| | - Linda Bittel
- Institute of Virology, Philipps-University, Marburg, Germany
| | | | - Lennart Kämper
- Institute of Virology, Philipps-University, Marburg, Germany
| | - Olga Dolnik
- Institute of Virology, Philipps-University, Marburg, Germany
| | - Verena Krähling
- Institute of Virology, Philipps-University, Marburg, Germany; German Center for Infection Research (DZIF), Partner Site Gießen-Marburg-Langen, Marburg, Germany
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2
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Gong M, Peng C, Yang C, Wang Z, Qian H, Hu X, Zhou P, Shan C, Ding Q. Genome-wide CRISPR/Cas9 screen identifies SLC39A9 and PIK3C3 as crucial entry factors for Ebola virus infection. PLoS Pathog 2024; 20:e1012444. [PMID: 39173055 DOI: 10.1371/journal.ppat.1012444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Accepted: 07/23/2024] [Indexed: 08/24/2024] Open
Abstract
The Ebola virus (EBOV) has emerged as a significant global health concern, notably during the 2013-2016 outbreak in West Africa. Despite the clinical approval of two EBOV antibody drugs, there is an urgent need for more diverse and effective antiviral drugs, along with comprehensive understanding of viral-host interactions. In this study, we harnessed a biologically contained EBOVΔVP30-EGFP cell culture model which could recapitulate the entire viral life cycle, to conduct a genome-wide CRISPR/Cas9 screen. Through this, we identified PIK3C3 (phosphatidylinositide 3-kinase) and SLC39A9 (zinc transporter) as crucial host factors for EBOV infection. Genetic depletion of SLC39A9 and PIK3C3 lead to reduction of EBOV entry, but not impact viral genome replication, suggesting that SLC39A9 and PIK3C3 act as entry factors, facilitating viral entry into host cells. Moreover, PIK3C3 kinase activity is indispensable for the internalization of EBOV virions, presumably through the regulation of endocytic and autophagic membrane traffic, which has been previously recognized as essential for EBOV internalization. Notably, our study demonstrated that PIK3C3 kinase inhibitor could effectively block EBOV infection, underscoring PIK3C3 as a promising drug target. Furthermore, biochemical analysis showed that recombinant SLC39A9 protein could directly bind viral GP protein, which further promotes the interaction of viral GP protein with cellular receptor NPC1. These findings suggests that SLC39A9 plays dual roles in EBOV entry. Initially, it serves as an attachment factor during the early entry phase by engaging with the viral GP protein. Subsequently, SLC39A9 functions an adaptor protein, facilitating the interaction between virions and the NPC1 receptor during the late entry phase, prior to cathepsin cleavage on the viral GP. In summary, this study offers novel insights into virus-host interactions, contributing valuable information for the development of new therapies against EBOV infection.
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Affiliation(s)
- Mingli Gong
- School of Basic Medical Sciences, Tsinghua University, Beijing, China
| | - Cheng Peng
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Chen Yang
- School of Basic Medical Sciences, Tsinghua University, Beijing, China
| | - Zhenhua Wang
- The First Affiliated Hospital of USTC, MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Research Center for Interdisciplinary Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Hongwu Qian
- The First Affiliated Hospital of USTC, MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Research Center for Interdisciplinary Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Xue Hu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Peng Zhou
- CAS Key Laboratory of Special Pathogens, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Chao Shan
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, Hubei, China
- CAS Key Laboratory of Special Pathogens, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, Hubei, China
| | - Qiang Ding
- School of Basic Medical Sciences, Tsinghua University, Beijing, China
- SXMU-Tsinghua Collaborative Innovation Center for Frontier Medicine, Shanxi Medical University, Taiyuan, China
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3
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Bodmer BS, Hoenen T, Wendt L. Molecular insights into the Ebola virus life cycle. Nat Microbiol 2024; 9:1417-1426. [PMID: 38783022 DOI: 10.1038/s41564-024-01703-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 04/17/2024] [Indexed: 05/25/2024]
Abstract
Ebola virus and other orthoebolaviruses cause severe haemorrhagic fevers in humans, with very high case fatality rates. Their non-segmented single-stranded RNA genome encodes only seven structural proteins and a small number of non-structural proteins to facilitate the virus life cycle. The basics of this life cycle are well established, but recent advances have substantially increased our understanding of its molecular details, including the viral and host factors involved. Here we provide a comprehensive overview of our current knowledge of the molecular details of the orthoebolavirus life cycle, with a special focus on proviral host factors. We discuss the multistep entry process, viral RNA synthesis in specialized phase-separated intracellular compartments called inclusion bodies, the expression of viral proteins and ultimately the assembly of new virus particles and their release at the cell surface. In doing so, we integrate recent studies into the increasingly detailed model that has developed for these fundamental aspects of orthoebolavirus biology.
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Affiliation(s)
- Bianca S Bodmer
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald - Insel Riems, Germany
| | - Thomas Hoenen
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald - Insel Riems, Germany.
| | - Lisa Wendt
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald - Insel Riems, Germany
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4
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Jain A, Govindan R, Berkman A, Luban J, Durham ND, Munro J. Regulation of Ebola GP conformation and membrane binding by the chemical environment of the late endosome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.18.524651. [PMID: 36711925 PMCID: PMC9882366 DOI: 10.1101/2023.01.18.524651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Interaction between the Ebola virus envelope glycoprotein (GP) and the endosomal membrane is an essential step during virus entry into the cell. Acidic pH and Ca2+ have been implicated in mediating the GP-membrane interaction. However, the molecular mechanism by which these environmental factors regulate the conformational changes that enable engagement of GP with the target membrane is unknown. Here, we apply fluorescence correlation spectroscopy (FCS) and single-molecule Forster resonance energy transfer (smFRET) imaging to elucidate how the acidic pH, Ca2+ and anionic phospholipids in the late endosome promote GP-membrane interaction, thereby facilitating virus entry. We find that bis(monoacylglycero)phosphate (BMP), which is specific to the late endosome, is especially critical in determining the Ca2+-dependence of the GP-membrane interaction. Molecular dynamics (MD) simulations suggested residues in GP that sense pH and induce conformational changes that make the fusion loop available for insertion into the membrane. We similarly confirm residues in the fusion loop that mediate GPs interaction with Ca2+, which likely promotes local conformational changes in the fusion loop and mediates electrostatic interactions with the anionic phospholipids. Collectively, our results provide a mechanistic understanding of how the environment of the late endosome regulates the timing and efficiency of virus entry.
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Abstract
There are at least 21 families of enveloped viruses that infect mammals, and many contain members of high concern for global human health. All enveloped viruses have a dedicated fusion protein or fusion complex that enacts the critical genome-releasing membrane fusion event that is essential before viral replication within the host cell interior can begin. Because all enveloped viruses enter cells by fusion, it behooves us to know how viral fusion proteins function. Viral fusion proteins are also major targets of neutralizing antibodies, and hence they serve as key vaccine immunogens. Here we review current concepts about viral membrane fusion proteins focusing on how they are triggered, structural intermediates between pre- and postfusion forms, and their interplay with the lipid bilayers they engage. We also discuss cellular and therapeutic interventions that thwart virus-cell membrane fusion.
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Affiliation(s)
- Judith M White
- Department of Cell Biology, University of Virginia, Charlottesville, Virginia, USA;
| | - Amanda E Ward
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, Virginia, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
| | - Laura Odongo
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, Virginia, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
| | - Lukas K Tamm
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, Virginia, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
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Odongo L, Habtegebrael BH, Kiessling V, White JM, Tamm LK. A novel in vitro system of supported planar endosomal membranes (SPEMs) reveals an enhancing role for cathepsin B in the final stage of Ebola virus fusion and entry. Microbiol Spectr 2023; 11:e0190823. [PMID: 37728342 PMCID: PMC10581071 DOI: 10.1128/spectrum.01908-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 07/17/2023] [Indexed: 09/21/2023] Open
Abstract
Ebola virus (EBOV) causes a hemorrhagic fever with fatality rates up to 90%. The EBOV entry process is complex and incompletely understood. Following attachment to host cells, EBOV is trafficked to late endosomes/lysosomes where its glycoprotein (GP) is processed to a 19-kDa form, which binds to the EBOV intracellular receptor Niemann-Pick type C1. We previously showed that the cathepsin protease inhibitor, E-64d, blocks infection by pseudovirus particles bearing 19-kDa GP, suggesting that further cathepsin action is needed to trigger fusion. This, however, has not been demonstrated directly. Since 19-kDa Ebola GP fusion occurs in late endosomes, we devised a system in which enriched late endosomes are used to prepare supported planar endosomal membranes (SPEMs), and fusion of fluorescent (pseudo)virus particles is monitored by total internal reflection fluorescence microscopy. We validated the system by demonstrating the pH dependencies of influenza virus hemagglutinin (HA)-mediated and Lassa virus (LASV) GP-mediated fusion. Using SPEMs, we showed that fusion mediated by 19-kDa Ebola GP is dependent on low pH, enhanced by Ca2+, and augmented by the addition of cathepsins. Subsequently, we found that E-64d inhibits full fusion, but not lipid mixing, mediated by 19-kDa GP, which we corroborated with the reversible cathepsin inhibitor VBY-825. Hence, we provide both gain- and loss-of-function evidence that further cathepsin action enhances the fusion activity of 19-kDa Ebola GP. In addition to providing new insights into how Ebola GP mediates fusion, the approach we developed employing SPEMs can now be broadly used for studies of virus and toxin entry through endosomes. IMPORTANCE Ebola virus is the causative agent of Ebola virus disease, which is severe and frequently lethal. EBOV gains entry into cells via late endosomes/lysosomes. The events immediately preceding fusion of the viral and endosomal membranes are incompletely understood. In this study, we report a novel in vitro system for studying virus fusion with endosomal membranes. We validated the system by demonstrating the low pH dependencies of influenza and Lassa virus fusion. Moreover, we show that further cathepsin B action enhances the fusion activity of the primed Ebola virus glycoprotein. Finally, this model endosomal membrane system should be useful in studying the mechanisms of bilayer breaching by other enveloped viruses, by non-enveloped viruses, and by acid-activated bacterial toxins.
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Affiliation(s)
- Laura Odongo
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, Virginia, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
| | - Betelihem H. Habtegebrael
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, Virginia, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
| | - Volker Kiessling
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, Virginia, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
| | - Judith M. White
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, Virginia, USA
- Department of Cell Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Lukas K. Tamm
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, Virginia, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
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Pseudotyped Viruses for Marburgvirus and Ebolavirus. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1407:105-132. [PMID: 36920694 DOI: 10.1007/978-981-99-0113-5_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
Marburg virus (MARV) and Ebola virus (EBOV) of the Filoviridae family are the most lethal viruses in terms of mortality rate. However, the development of antiviral treatment is hampered by the requirement for biosafety level-4 (BSL-4) containment. The establishment of BSL-2 pseudotyped viruses can provide important tools for the study of filoviruses. This chapter summarizes general information on the filoviruses and then focuses on the construction of replication-deficient pseudotyped MARV and EBOV (e.g., lentivirus system and vesicular stomatitis virus system). It also details the potential applications of the pseudotyped viruses, including neutralization antibody detection, the study of infection mechanisms, the evaluation of antibody-dependent enhancement, virus entry inhibitor screening, and glycoprotein mutation analysis.
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8
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A CRISPR-Cas9 screen reveals a role for WD repeat-containing protein 81 (WDR81) in the entry of late penetrating viruses. PLoS Pathog 2022; 18:e1010398. [PMID: 35320319 PMCID: PMC8942271 DOI: 10.1371/journal.ppat.1010398] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 02/25/2022] [Indexed: 12/02/2022] Open
Abstract
Successful initiation of infection by many different viruses requires their uptake into the endosomal compartment. While some viruses exit this compartment early, others must reach the degradative, acidic environment of the late endosome. Mammalian orthoreovirus (reovirus) is one such late penetrating virus. To identify host factors that are important for reovirus infection, we performed a CRISPR-Cas9 knockout (KO) screen that targets over 20,000 genes in fibroblasts derived from the embryos of C57/BL6 mice. We identified seven genes (WDR81, WDR91, RAB7, CCZ1, CTSL, GNPTAB, and SLC35A1) that were required for the induction of cell death by reovirus. Notably, CRISPR-mediated KO of WD repeat-containing protein 81 (WDR81) rendered cells resistant to reovirus infection. Susceptibility to reovirus infection was restored by complementing KO cells with human WDR81. Although the absence of WDR81 did not affect viral attachment efficiency or uptake into the endosomal compartments for initial disassembly, it reduced viral gene expression and diminished infectious virus production. Consistent with the role of WDR81 in impacting the maturation of endosomes, WDR81-deficiency led to the accumulation of reovirus particles in dead-end compartments. Though WDR81 was dispensable for infection by VSV (vesicular stomatitis virus), which exits the endosomal system at an early stage, it was required for VSV-EBO GP (VSV that expresses the Ebolavirus glycoprotein), which must reach the late endosome to initiate infection. These results reveal a previously unappreciated role for WDR81 in promoting the replication of viruses that transit through late endosomes. Viruses are obligate intracellular parasites that require the contributions of numerous host factors to complete the viral life cycle. Thus, the host-pathogen interaction can regulate cell death signaling and virus entry, replication, assembly, and egress. Functional genetic screens are useful tools to identify host factors that are important for establishing infection. Such information can also be used to understand cell biology. Notably, genome-scale CRISPR-Cas9 knockout screens are robust due to their specificity and the loss of host gene expression. Mammalian orthoreovirus (reovirus) is a tractable model system to investigate the pathogenesis of neurotropic and cardiotropic viruses. Using a CRISPR-Cas9 screen, we identified WD repeat-containing protein 81 (WDR81) as a host factor required for efficient reovirus infection of murine cells. Ablation of WDR81 blocked a late step in the viral entry pathway. Further, our work indicates that WDR81 is required for the entry of vesicular stomatitis virus that expresses the Ebolavirus glycoprotein.
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Ortega-Gonzalez P, Taylor G, Jangra RK, Tenorio R, Fernandez de Castro I, Mainou BA, Orchard RC, Wilen CB, Brigleb PH, Sojati J, Chandran K, Sachse M, Risco C, Dermody TS. Reovirus infection is regulated by NPC1 and endosomal cholesterol homeostasis. PLoS Pathog 2022; 18:e1010322. [PMID: 35263388 PMCID: PMC8906592 DOI: 10.1371/journal.ppat.1010322] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 01/28/2022] [Indexed: 11/19/2022] Open
Abstract
Cholesterol homeostasis is required for the replication of many viruses, including Ebola virus, hepatitis C virus, and human immunodeficiency virus-1. Niemann-Pick C1 (NPC1) is an endosomal-lysosomal membrane protein involved in cholesterol trafficking from late endosomes and lysosomes to the endoplasmic reticulum. We identified NPC1 in CRISPR and RNA interference screens as a putative host factor for infection by mammalian orthoreovirus (reovirus). Following internalization via clathrin-mediated endocytosis, the reovirus outer capsid is proteolytically removed, the endosomal membrane is disrupted, and the viral core is released into the cytoplasm where viral transcription, genome replication, and assembly take place. We found that reovirus infection is significantly impaired in cells lacking NPC1, but infection is restored by treatment of cells with hydroxypropyl-β-cyclodextrin, which binds and solubilizes cholesterol. Absence of NPC1 did not dampen infection by infectious subvirion particles, which are reovirus disassembly intermediates that bypass the endocytic pathway for infection of target cells. NPC1 is not required for reovirus attachment to the plasma membrane, internalization into cells, or uncoating within endosomes. Instead, NPC1 is required for delivery of transcriptionally active reovirus core particles from endosomes into the cytoplasm. These findings suggest that cholesterol homeostasis, ensured by NPC1 transport activity, is required for reovirus penetration into the cytoplasm, pointing to a new function for NPC1 and cholesterol homeostasis in viral infection. Genetic screens are useful strategies to identify host factors required for viral infection. NPC1 was identified in independent CRISPR and RNA interference screens as a putative host factor required for reovirus replication. We discovered that NPC1-mediated cholesterol transport is dispensable for reovirus attachment, internalization, and disassembly but required for penetration of the viral disassembly intermediate from late endosomes into the cytoplasm. These findings uncover an essential function for cholesterol in the entry of reovirus and raise the possibility that cholesterol homeostasis regulates the entry of other viruses that penetrate late endosomes to initiate replication.
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Affiliation(s)
- Paula Ortega-Gonzalez
- Cell Structure Laboratory, National Center for Biotechnology, CNB-CSIC, campus UAM, Cantoblanco, Madrid, Spain
- PhD Program in Molecular Biosciences, Autonoma de Madrid University, Madrid, Spain
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- Institute of Infection, Inflammation, and Immunity, UPMC Children’s Hospital of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Gwen Taylor
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- Institute of Infection, Inflammation, and Immunity, UPMC Children’s Hospital of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Rohit K. Jangra
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Raquel Tenorio
- Cell Structure Laboratory, National Center for Biotechnology, CNB-CSIC, campus UAM, Cantoblanco, Madrid, Spain
| | - Isabel Fernandez de Castro
- Cell Structure Laboratory, National Center for Biotechnology, CNB-CSIC, campus UAM, Cantoblanco, Madrid, Spain
| | - Bernardo A. Mainou
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Robert C. Orchard
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Craig B. Wilen
- Departments of Laboratory Medicine and Immunobiology, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Pamela H. Brigleb
- Institute of Infection, Inflammation, and Immunity, UPMC Children’s Hospital of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Jorna Sojati
- Institute of Infection, Inflammation, and Immunity, UPMC Children’s Hospital of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Kartik Chandran
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Martin Sachse
- Cell Structure Laboratory, National Center for Biotechnology, CNB-CSIC, campus UAM, Cantoblanco, Madrid, Spain
| | - Cristina Risco
- Cell Structure Laboratory, National Center for Biotechnology, CNB-CSIC, campus UAM, Cantoblanco, Madrid, Spain
- * E-mail: (C.R); (T.S.D)
| | - Terence S. Dermody
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- Institute of Infection, Inflammation, and Immunity, UPMC Children’s Hospital of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- * E-mail: (C.R); (T.S.D)
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Li Y, Wang J, Hou W, Shan Y, Wang S, Liu F. Dynamic Dissection of the Endocytosis of Porcine Epidemic Diarrhea Coronavirus Cooperatively Mediated by Clathrin and Caveolae as Visualized by Single-Virus Tracking. mBio 2021; 12:e00256-21. [PMID: 33785615 PMCID: PMC8092227 DOI: 10.1128/mbio.00256-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 02/25/2021] [Indexed: 12/14/2022] Open
Abstract
Coronaviruses (CoVs) have caused severe diseases in humans and animals. Endocytic pathways, such as clathrin-mediated endocytosis (CME) and caveolae-mediated endocytosis (CavME), play an important role for CoVs to penetrate the cell membrane barrier. In this study, a novel CoV entry manner is unraveled in which clathrin and caveolae can cooperatively mediate endocytosis of porcine epidemic diarrhea coronavirus (PEDV). Using multicolor live-cell imaging, the dynamics of the fluorescently labeled clathrin structures, caveolae structures, and PEDV were dissected. During CavME of PEDV, we found that clathrin structures can fuse with caveolae near the cell plasma membrane, and the average time of PEDV penetrating the cell membrane was within ∼3 min, exhibiting a rapid course of PEDV entry. Moreover, based on the dynamic recruitment of clathrin and caveolae structures and viral motility, the direct evidence also shows that about 20% of PEDVs can undergo an abortive entry via CME and CavME. Additionally, the dynamic trafficking of PEDV from clathrin and caveolae structures to early endosomes, and from early endosomes to late endosomes, and viral fusion were directly dissected, and PEDV fusion mainly occurred in late endosomes within ∼6.8 min after the transport of PEDV to late endosomes. Collectively, this work systematically unravels the early steps of PEDV infection, which expands our understanding of the mechanism of CoV infection.IMPORTANCE Emerging and re-emerging coronaviruses cause serious human and animal epidemics worldwide. For many enveloped viruses, including coronavirus, it is evident that breaking the plasma membrane barrier is a pivotal and complex process, which contains multiple dynamic steps. Although great efforts have been made to understand the mechanisms of coronavirus endocytic pathways, the direct real-time imaging of individual porcine epidemic diarrhea coronavirus (PEDV) internalization has not been achieved yet. In this study, we not only dissected the kinetics of PEDV entry via clathrin-mediated endocytosis and caveolae-mediated endocytosis and the kinetics of endosome trafficking and viral fusion but also found a novel productive coronavirus entry manner in which clathrin and caveolae can cooperatively mediate endocytosis of PEDV. Moreover, we uncovered the existence of PEDV abortive endocytosis. In summary, the productive PEDV entry via the cooperation between clathrin and caveolae structures and the abortive endocytosis of PEDV provide new insights into coronavirus penetrating the plasma membrane barrier.
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Affiliation(s)
- Yangyang Li
- Joint International Research Laboratory of Animal Health and Food Safety of Ministry of Education and Single Molecule Nanometry Laboratory (Sinmolab), Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Jian Wang
- Joint International Research Laboratory of Animal Health and Food Safety of Ministry of Education and Single Molecule Nanometry Laboratory (Sinmolab), Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Wei Hou
- Joint International Research Laboratory of Animal Health and Food Safety of Ministry of Education and Single Molecule Nanometry Laboratory (Sinmolab), Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Yanke Shan
- Joint International Research Laboratory of Animal Health and Food Safety of Ministry of Education and Single Molecule Nanometry Laboratory (Sinmolab), Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Shouyu Wang
- Joint International Research Laboratory of Animal Health and Food Safety of Ministry of Education and Single Molecule Nanometry Laboratory (Sinmolab), Nanjing Agricultural University, Nanjing, Jiangsu, China
- Computational Optics Laboratory, Jiangnan University, Wuxi, Jiangsu, China
| | - Fei Liu
- Joint International Research Laboratory of Animal Health and Food Safety of Ministry of Education and Single Molecule Nanometry Laboratory (Sinmolab), Nanjing Agricultural University, Nanjing, Jiangsu, China
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11
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Li T, Li Z, Deans EE, Mittler E, Liu M, Chandran K, Ivanovic T. The shape of pleomorphic virions determines resistance to cell-entry pressure. Nat Microbiol 2021; 6:617-629. [PMID: 33737748 DOI: 10.1038/s41564-021-00877-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 02/10/2021] [Indexed: 11/09/2022]
Abstract
Many enveloped animal viruses produce a variety of particle shapes, ranging from small spherical to long filamentous types. Characterization of how the shape of the virion affects infectivity has been difficult because the shape is only partially genetically encoded, and most pleomorphic virus structures have no selective advantage in vitro. Here, we apply virus fractionation using low-force sedimentation, as well as antibody neutralization coupled with RNAScope, single-particle membrane fusion experiments and stochastic simulations to evaluate the effects of differently shaped influenza A viruses and influenza viruses pseudotyped with Ebola glycoprotein on the infection of cells. Our results reveal that the shape of the virus particles determines the probability of both virus attachment and membrane fusion when viral glycoprotein activity is compromised. The larger contact interface between a cell and a larger particle offers a greater probability that several active glycoproteins are adjacent to each other and can cooperate to induce membrane merger. Particles with a length of tens of micrometres can fuse even when 95% of the glycoproteins are inactivated. We hypothesize that non-genetically encoded variable particle shapes enable pleomorphic viruses to overcome selective pressure and may enable adaptation to infection of cells by emerging viruses such as Ebola. Our results suggest that therapeutics targeting filamentous virus particles could overcome antiviral drug resistance and immune evasion in pleomorphic viruses.
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Affiliation(s)
- Tian Li
- Biochemistry Department, Brandeis University, Waltham, MA, USA
| | - Zhenyu Li
- Biochemistry Department, Brandeis University, Waltham, MA, USA
| | - Erin E Deans
- Biochemistry Department, Brandeis University, Waltham, MA, USA
| | - Eva Mittler
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, USA
| | - Meisui Liu
- Biochemistry Department, Brandeis University, Waltham, MA, USA
| | - Kartik Chandran
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, USA
| | - Tijana Ivanovic
- Biochemistry Department, Brandeis University, Waltham, MA, USA.
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12
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Formulation, Stability, Pharmacokinetic, and Modeling Studies for Tests of Synergistic Combinations of Orally Available Approved Drugs against Ebola Virus In Vivo. Microorganisms 2021; 9:microorganisms9030566. [PMID: 33801811 PMCID: PMC7998926 DOI: 10.3390/microorganisms9030566] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 03/01/2021] [Accepted: 03/05/2021] [Indexed: 12/28/2022] Open
Abstract
Outbreaks of Ebola ebolavirus (EBOV) have been associated with high morbidity and mortality. Milestones have been reached recently in the management of EBOV disease (EVD) with licensure of an EBOV vaccine and two monoclonal antibody therapies. However, neither vaccines nor therapies are available for other disease-causing filoviruses. In preparation for such outbreaks, and for more facile and cost-effective management of EVD, we seek a cocktail containing orally available and room temperature stable drugs with strong activity against multiple filoviruses. We previously showed that (bepridil + sertraline) and (sertraline + toremifene) synergistically suppress EBOV in cell cultures. Here, we describe steps towards testing these combinations in a mouse model of EVD. We identified a vehicle suitable for oral delivery of the component drugs and determined that, thus formulated the drugs are equally active against EBOV as preparations in DMSO, and they maintain activity upon storage in solution for up to seven days. Pharmacokinetic (PK) studies indicated that the drugs in the oral delivery vehicle are well tolerated in mice at the highest doses tested. Collectively the data support advancement of these combinations to tests for synergy in a mouse model of EVD. Moreover, mathematical modeling based on human oral PK projects that the combinations would be more active in humans than their component single drugs.
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13
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A Glycoprotein Mutation That Emerged during the 2013-2016 Ebola Virus Epidemic Alters Proteolysis and Accelerates Membrane Fusion. mBio 2021; 12:mBio.03616-20. [PMID: 33593971 PMCID: PMC8545129 DOI: 10.1128/mbio.03616-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Genomic surveillance of viral isolates during the 2013–2016 Ebola virus epidemic in Western Africa, the largest and most devastating filovirus outbreak on record, revealed several novel mutations. The responsible strain, named Makona, carries an A-to-V substitution at position 82 (A82V) in the glycoprotein (GP), which is associated with enhanced infectivity in vitro. Here, we investigated the mechanistic basis for this enhancement as well as the interplay between A82V and a T-to-I substitution at residue 544 of GP, which also modulates infectivity in cell culture. We found that both 82V and 544I destabilize GP, with the residue at position 544 impacting overall stability, while 82V specifically destabilizes proteolytically cleaved GP. Both residues also promote faster kinetics of lipid mixing of the viral and host membranes in live cells, individually and in tandem, which correlates with faster times to fusion following colocalization with the viral receptor Niemann-Pick C1 (NPC1). Furthermore, GPs bearing 82V are more sensitive to proteolysis by cathepsin L (CatL), a key host factor for viral entry. Intriguingly, CatL processed 82V variant GPs to a novel product with a molecular weight of approximately 12,000 (12K), which we hypothesize corresponds to a form of GP that is pre-triggered for fusion. We thus propose a model in which 82V promotes more efficient GP processing by CatL, leading to faster viral fusion kinetics and higher levels of infectivity.
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14
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Stewart CM, Phan A, Bo Y, LeBlond ND, Smith TKT, Laroche G, Giguère PM, Fullerton MD, Pelchat M, Kobasa D, Côté M. Ebola virus triggers receptor tyrosine kinase-dependent signaling to promote the delivery of viral particles to entry-conducive intracellular compartments. PLoS Pathog 2021; 17:e1009275. [PMID: 33513206 PMCID: PMC7875390 DOI: 10.1371/journal.ppat.1009275] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 02/10/2021] [Accepted: 01/04/2021] [Indexed: 11/23/2022] Open
Abstract
Filoviruses, such as the Ebola virus (EBOV) and Marburg virus (MARV), are causative agents of sporadic outbreaks of hemorrhagic fevers in humans. To infect cells, filoviruses are internalized via macropinocytosis and traffic through the endosomal pathway where host cathepsin-dependent cleavage of the viral glycoproteins occurs. Subsequently, the cleaved viral glycoprotein interacts with the late endosome/lysosome resident host protein, Niemann-Pick C1 (NPC1). This interaction is hypothesized to trigger viral and host membrane fusion, which results in the delivery of the viral genome into the cytoplasm and subsequent initiation of replication. Some studies suggest that EBOV viral particles activate signaling cascades and host-trafficking factors to promote their localization with host factors that are essential for entry. However, the mechanism through which these activating signals are initiated remains unknown. By screening a kinase inhibitor library, we found that receptor tyrosine kinase inhibitors potently block EBOV and MARV GP-dependent viral entry. Inhibitors of epidermal growth factor receptor (EGFR), tyrosine protein kinase Met (c-Met), and the insulin receptor (InsR)/insulin like growth factor 1 receptor (IGF1R) blocked filoviral GP-mediated entry and prevented growth of replicative EBOV in Vero cells. Furthermore, inhibitors of c-Met and InsR/IGF1R also blocked viral entry in macrophages, the primary targets of EBOV infection. Interestingly, while the c-Met and InsR/IGF1R inhibitors interfered with EBOV trafficking to NPC1, virus delivery to the receptor was not impaired in the presence of the EGFR inhibitor. Instead, we observed that the NPC1 positive compartments were phenotypically altered and rendered incompetent to permit viral entry. Despite their different mechanisms of action, all three RTK inhibitors tested inhibited virus-induced Akt activation, providing a possible explanation for how EBOV may activate signaling pathways during entry. In sum, these studies strongly suggest that receptor tyrosine kinases initiate signaling cascades essential for efficient post-internalization entry steps. Ebola virus (EBOV) and Marburg virus (MARV) are zoonotic pathogens that can cause severe hemorrhagic fevers in humans and non-human primates. They are members of the growing Filoviridae family that also includes three other species of Ebolaviruses known to be highly pathogenic in humans. While vaccines for EBOV are being deployed and showed high efficacy, pan-filoviral treatment is still lacking. To infect cells, EBOV requires the endosomal/lysosomal resident protein Niemann-Pick C1 (NPC1). Accordingly, viral particles require extensive trafficking within endosomal pathways for entry and delivery of the viral genome into the host cell cytoplasm. Here, we used chemical biology to reveal that EBOV triggers receptor tyrosine kinase (RTK)-dependent signaling to traffic to intracellular vesicles that contain the receptor and are conducive to entry. The characterization of host trafficking factors and signaling pathways that are potentially triggered by the virus are important as these could be targeted for antiviral therapies. In our study, we identified several RTK inhibitors, some of which are FDA-approved drugs, that potently block EBOV infection. Since all filoviruses known to date, even Měnglà virus that was recently discovered in bats in China, use NPC1 as their entry receptor, these inhibitors have the potential to be effective pan-filovirus antivirals.
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Affiliation(s)
- Corina M. Stewart
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada
- Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Canada
- Centre for Infection, Immunity, and Inflammation, University of Ottawa, Ottawa, Canada
| | - Alexandra Phan
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada
- Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Canada
- Centre for Infection, Immunity, and Inflammation, University of Ottawa, Ottawa, Canada
| | - Yuxia Bo
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada
- Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Canada
- Centre for Infection, Immunity, and Inflammation, University of Ottawa, Ottawa, Canada
| | - Nicholas D. LeBlond
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada
- Centre for Infection, Immunity, and Inflammation, University of Ottawa, Ottawa, Canada
| | - Tyler K. T. Smith
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada
- Centre for Infection, Immunity, and Inflammation, University of Ottawa, Ottawa, Canada
| | - Geneviève Laroche
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada
| | - Patrick M. Giguère
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada
| | - Morgan D. Fullerton
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada
- Centre for Infection, Immunity, and Inflammation, University of Ottawa, Ottawa, Canada
- Centre for Catalysis Research and Innovation, University of Ottawa, Ottawa, Canada
| | - Martin Pelchat
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada
| | - Darwyn Kobasa
- Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Canada
- Department of Medical Microbiology, University of Manitoba, Winnipeg, Canada
| | - Marceline Côté
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada
- Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Canada
- Centre for Infection, Immunity, and Inflammation, University of Ottawa, Ottawa, Canada
- Centre for Catalysis Research and Innovation, University of Ottawa, Ottawa, Canada
- * E-mail:
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15
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Direct Intracellular Visualization of Ebola Virus-Receptor Interaction by In Situ Proximity Ligation. mBio 2021; 12:mBio.03100-20. [PMID: 33436438 PMCID: PMC7844541 DOI: 10.1128/mbio.03100-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Ebola virus causes episodic but increasingly frequent outbreaks of severe disease in Middle Africa, as shown by the recently overcome second largest outbreak on record in the Democratic Republic of Congo. Despite considerable effort, FDA-approved antifiloviral therapeutics or targeted interventions are not available yet. Ebola virus (EBOV) entry into host cells comprises stepwise and extensive interactions of the sole viral surface glycoprotein (GP) with multiple host factors. During the intricate process, following virus uptake and trafficking to late endosomal/lysosomal compartments, GP is proteolytically processed to cleaved GP (GPCL) by the endosomal proteases cathepsin B and L, unmasking GP’s receptor-binding site. Engagement of GPCL with the universal filoviral intracellular receptor Niemann-Pick C1 (NPC1) eventually culminates in fusion between viral and cellular membranes, cytoplasmic escape of the viral nucleocapsid, and subsequent infection. Mechanistic delineation of the indispensable GPCL-NPC1-binding step has been severely hampered by the unavailability of a robust cell-based assay assessing interaction of GPCL with full-length endosomal NPC1. Here, we describe a novel in situ assay to monitor GPCL-NPC1 engagement in intact, infected cells. Visualization of the subcellular localization of binding complexes is based on the principle of DNA-assisted, antibody-mediated proximity ligation. Virus-receptor binding monitored by proximity ligation was contingent on GP’s proteolytic cleavage and was sensitive to perturbations in the GPCL-NPC1 interface. Our assay also specifically decoupled detection of virus-receptor binding from steps post-receptor binding, such as membrane fusion and infection. Testing of multiple FDA-approved small-molecule inhibitors revealed that drug treatments inhibited virus entry and GPCL-NPC1 recognition by distinctive mechanisms. Together, here we present a newly established proximity ligation assay, which will allow us to dissect cellular and viral requirements for filovirus-receptor binding and to delineate the mechanisms of action of inhibitors on filovirus entry in a cell-based system.
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16
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Bruchez A, Sha K, Johnson J, Chen L, Stefani C, McConnell H, Gaucherand L, Prins R, Matreyek KA, Hume AJ, Mühlberger E, Schmidt EV, Olinger GG, Stuart LM, Lacy-Hulbert A. MHC class II transactivator CIITA induces cell resistance to Ebola virus and SARS-like coronaviruses. Science 2020; 370:241-247. [PMID: 32855215 PMCID: PMC7665841 DOI: 10.1126/science.abb3753] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 08/20/2020] [Indexed: 01/01/2023]
Abstract
Recent outbreaks of Ebola virus (EBOV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have exposed our limited therapeutic options for such diseases and our poor understanding of the cellular mechanisms that block viral infections. Using a transposon-mediated gene-activation screen in human cells, we identify that the major histocompatibility complex (MHC) class II transactivator (CIITA) has antiviral activity against EBOV. CIITA induces resistance by activating expression of the p41 isoform of invariant chain CD74, which inhibits viral entry by blocking cathepsin-mediated processing of the Ebola glycoprotein. We further show that CD74 p41 can block the endosomal entry pathway of coronaviruses, including SARS-CoV-2. These data therefore implicate CIITA and CD74 in host defense against a range of viruses, and they identify an additional function of these proteins beyond their canonical roles in antigen presentation.
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MESH Headings
- Antigens, Differentiation, B-Lymphocyte/genetics
- Antigens, Differentiation, B-Lymphocyte/physiology
- Betacoronavirus/physiology
- COVID-19
- Cell Line, Tumor
- Coronavirus Infections/immunology
- Coronavirus Infections/virology
- DNA Transposable Elements
- Ebolavirus/physiology
- Endosomes/virology
- Genetic Testing
- Hemorrhagic Fever, Ebola/immunology
- Hemorrhagic Fever, Ebola/virology
- Histocompatibility Antigens Class II/genetics
- Histocompatibility Antigens Class II/physiology
- Host-Pathogen Interactions/genetics
- Host-Pathogen Interactions/immunology
- Humans
- Nuclear Proteins/genetics
- Nuclear Proteins/physiology
- Pandemics
- Pneumonia, Viral/immunology
- Pneumonia, Viral/virology
- SARS-CoV-2
- Trans-Activators/genetics
- Trans-Activators/physiology
- Transcription, Genetic
- Virus Internalization
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Affiliation(s)
- Anna Bruchez
- Benaroya Research Institute, Seattle, WA 98101, USA
| | - Ky Sha
- Benaroya Research Institute, Seattle, WA 98101, USA
| | - Joshua Johnson
- National Institute of Allergy and Infectious Diseases (NIAID) Integrated Research Facility, Frederick, MD 21702, USA
| | - Li Chen
- Massachusetts General Hospital, Boston, MA 02114, USA
| | | | | | | | - Rachel Prins
- Benaroya Research Institute, Seattle, WA 98101, USA
| | - Kenneth A Matreyek
- Department of Genome Sciences, University of Washington, Seattle, WA 98109, USA
| | - Adam J Hume
- Boston University School of Medicine, Boston, MA 02118, USA
- National Emerging Infectious Diseases Laboratories, Boston University, Boston, MA 02118, USA
| | - Elke Mühlberger
- Boston University School of Medicine, Boston, MA 02118, USA
- National Emerging Infectious Diseases Laboratories, Boston University, Boston, MA 02118, USA
| | | | - Gene G Olinger
- National Institute of Allergy and Infectious Diseases (NIAID) Integrated Research Facility, Frederick, MD 21702, USA
- Boston University School of Medicine, Boston, MA 02118, USA
- National Emerging Infectious Diseases Laboratories, Boston University, Boston, MA 02118, USA
- MRIGlobal, Gaithersburg, MD 20878, USA
| | - Lynda M Stuart
- Benaroya Research Institute, Seattle, WA 98101, USA
- Bill and Melinda Gates Foundation, Seattle, WA 98109, USA
| | - Adam Lacy-Hulbert
- Benaroya Research Institute, Seattle, WA 98101, USA.
- Department of Immunology, University of Washington, Seattle, WA 98109, USA
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17
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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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18
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Kang YL, Chou YY, Rothlauf PW, Liu Z, Soh TK, Cureton D, Case JB, Chen RE, Diamond MS, Whelan SPJ, Kirchhausen T. Inhibition of PIKfyve kinase prevents infection by Zaire ebolavirus and SARS-CoV-2. Proc Natl Acad Sci U S A 2020; 117:20803-20813. [PMID: 32764148 PMCID: PMC7456157 DOI: 10.1073/pnas.2007837117] [Citation(s) in RCA: 141] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Virus entry is a multistep process. It initiates when the virus attaches to the host cell and ends when the viral contents reach the cytosol. Genetically unrelated viruses can subvert analogous subcellular mechanisms and use similar trafficking pathways for successful entry. Antiviral strategies targeting early steps of infection are therefore appealing, particularly when the probability for successful interference through a common step is highest. We describe here potent inhibitory effects on content release and infection by chimeric vesicular stomatitis virus (VSV) containing the envelope proteins of Zaire ebolavirus (VSV-ZEBOV) or severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (VSV-SARS-CoV-2) elicited by Apilimod and Vacuolin-1, small-molecule inhibitors of the main endosomal phosphatidylinositol-3-phosphate/phosphatidylinositol 5-kinase, PIKfyve. We also describe potent inhibition of SARS-CoV-2 strain 2019-nCoV/USA-WA1/2020 by Apilimod. These results define tools for studying the intracellular trafficking of pathogens elicited by inhibition of PIKfyve kinase and suggest the potential for targeting this kinase in developing small-molecule antivirals against SARS-CoV-2.
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Affiliation(s)
- Yuan-Lin Kang
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
| | - Yi-Ying Chou
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
| | - Paul W Rothlauf
- Department of Molecular Microbiology, Washington University in St. Louis, St. Louis, MO 63110
- Program in Virology, Harvard Medical School, Boston, MA 02115
| | - Zhuoming Liu
- Department of Molecular Microbiology, Washington University in St. Louis, St. Louis, MO 63110
| | - Timothy K Soh
- Program in Virology, Harvard Medical School, Boston, MA 02115
| | - David Cureton
- Program in Virology, Harvard Medical School, Boston, MA 02115
- Boehringer Ingelheim Animal Health, Inc. Duluth, GA 30096
| | - James Brett Case
- Department of Medicine, Washington University in St. Louis, St. Louis, MO 63110
| | - Rita E Chen
- Department of Medicine, Washington University in St. Louis, St. Louis, MO 63110
- Department of Pathology & Immunology, Washington University in St. Louis, St. Louis, MO 63110
| | - Michael S Diamond
- Department of Molecular Microbiology, Washington University in St. Louis, St. Louis, MO 63110
- Department of Medicine, Washington University in St. Louis, St. Louis, MO 63110
- Department of Pathology & Immunology, Washington University in St. Louis, St. Louis, MO 63110
| | - Sean P J Whelan
- Department of Molecular Microbiology, Washington University in St. Louis, St. Louis, MO 63110;
| | - Tom Kirchhausen
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115;
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115
- Department of Pediatrics, Harvard Medical School, Boston, MA 02115
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19
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Filoviruses Use the HOPS Complex and UVRAG To Traffic to Niemann-Pick C1 Compartments during Viral Entry. J Virol 2020; 94:JVI.01002-20. [PMID: 32493822 PMCID: PMC7394885 DOI: 10.1128/jvi.01002-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 05/23/2020] [Indexed: 02/06/2023] Open
Abstract
Ebola viruses (EBOV) and other filoviruses cause sporadic and unpredictable outbreaks of highly lethal diseases. The lack of FDA-approved therapeutics, particularly ones with panfiloviral specificity, highlights the need for continued research efforts to understand aspects of the viral life cycle that are common to all filoviruses. As such, viral entry is of particular interest, as all filoviruses must reach cellular compartments containing the viral receptor Niemann-Pick C1 to enter cells. Here, we present an inducible CRISPR/Cas9 method to rapidly and efficiently generate knockout cells in order to interrogate the roles of a broad range of host factors in viral entry. Using this approach, we showed that EBOV entry depends on both the homotypic fusion and protein sorting (HOPS) tethering complex in coordination with UV radiation resistance-associated gene (UVRAG). Importantly, we demonstrate that the HOPS complex and UVRAG are required by all pathogenic filoviruses, representing potential targets for panfiloviral therapeutics. Ebola virus (EBOV) entry requires internalization into host cells and extensive trafficking through the endolysosomal network in order to reach late endosomal/lysosomal compartments that contain triggering factors for viral membrane fusion. These triggering factors include low-pH-activated cellular cathepsin proteases, which cleave the EBOV glycoprotein (GP), exposing a domain which binds to the filoviral receptor, the cholesterol transporter Niemann-Pick C1 (NPC1). Here, we report that trafficking of EBOV to NPC1 requires expression of the homotypic fusion and protein sorting (HOPS) tethering complex as well as its regulator, UV radiation resistance-associated gene (UVRAG). Using an inducible clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system, we demonstrated that depletion of HOPS subunits as well as UVRAG impairs entry by all pathogenic filoviruses. UVRAG depletion resulted in reduced delivery of EBOV virions to NPC1+ cellular compartments. Furthermore, we show that deletion of a domain on UVRAG known to be required for interaction with the HOPS complex results in impaired EBOV entry. Taken together, our studies demonstrate that EBOV requires both expression of and coordination between the HOPS complex and UVRAG in order to mediate efficient viral entry. IMPORTANCE Ebola viruses (EBOV) and other filoviruses cause sporadic and unpredictable outbreaks of highly lethal diseases. The lack of FDA-approved therapeutics, particularly ones with panfiloviral specificity, highlights the need for continued research efforts to understand aspects of the viral life cycle that are common to all filoviruses. As such, viral entry is of particular interest, as all filoviruses must reach cellular compartments containing the viral receptor Niemann-Pick C1 to enter cells. Here, we present an inducible CRISPR/Cas9 method to rapidly and efficiently generate knockout cells in order to interrogate the roles of a broad range of host factors in viral entry. Using this approach, we showed that EBOV entry depends on both the homotypic fusion and protein sorting (HOPS) tethering complex in coordination with UV radiation resistance-associated gene (UVRAG). Importantly, we demonstrate that the HOPS complex and UVRAG are required by all pathogenic filoviruses, representing potential targets for panfiloviral therapeutics.
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20
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Kang YL, Chou YY, Rothlauf PW, Liu Z, Soh TK, Cureton D, Case JB, Chen RE, Diamond MS, Whelan SPJ, Kirchhausen T. Inhibition of PIKfyve kinase prevents infection by Zaire ebolavirus and SARS-CoV-2. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2020. [PMID: 32511398 DOI: 10.1101/2020.04.21.053058] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Virus entry is a multistep process. It initiates when the virus attaches to the host cell and ends when the viral contents reach the cytosol. Genetically unrelated viruses can subvert analogous subcellular mechanisms and use similar trafficking pathways for successful entry. Antiviral strategies targeting early steps of infection are therefore appealing, particularly when the probability for successful interference through a common step is highest. We describe here potent inhibitory effects on content release and infection by chimeric VSV containing the envelope proteins of Zaire ebolavirus (VSV-ZEBOV) or SARS-CoV-2 (VSV-SARS-CoV-2) elicited by Apilimod and Vacuolin-1, small molecule inhibitors of the main endosomal Phosphatidylinositol-3-Phosphate/Phosphatidylinositol 5-Kinase, PIKfyve. We also describe potent inhibition of SARS-CoV-2 strain 2019-nCoV/USA-WA1/2020 by Apilimod. These results define new tools for studying the intracellular trafficking of pathogens elicited by inhibition of PIKfyve kinase and suggest the potential for targeting this kinase in developing small-molecule antivirals against SARS-CoV-2.
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21
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Jia M, Liberatore RA, Guo Y, Chan KW, Pan R, Lu H, Waltari E, Mittler E, Chandran K, Finzi A, Kaufmann DE, Seaman MS, Ho DD, Shapiro L, Sheng Z, Kong XP, Bieniasz PD, Wu X. VSV-Displayed HIV-1 Envelope Identifies Broadly Neutralizing Antibodies Class-Switched to IgG and IgA. Cell Host Microbe 2020; 27:963-975.e5. [PMID: 32315598 PMCID: PMC7294236 DOI: 10.1016/j.chom.2020.03.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 02/27/2020] [Accepted: 03/26/2020] [Indexed: 12/25/2022]
Abstract
The HIV-1 envelope (Env) undergoes conformational changes during infection. Broadly neutralizing antibodies (bNAbs) are typically isolated by using soluble Env trimers, which do not capture all Env states. To address these limitations, we devised a vesicular stomatitis virus (VSV)-based probe to display membrane-embedded Env trimers and isolated five bNAbs from two chronically infected donors, M4008 and M1214. Donor B cell receptor (BCR) repertoires identified two bNAb lineages, M4008_N1 and M1214_N1, that class-switched to immunoglobulin G (IgG) and IgA. Variants of these bNAbs reconstituted as IgA demonstrated broadly neutralizing activity, and the IgA fraction of M1214 plasma conferred neutralization. M4008_N1 epitope mapping revealed a glycan-independent V3 epitope conferring tier 2 virus neutralization. A 4.86-Å-resolution cryogenic electron microscopy (cryo-EM) structure of M1214_N1 complexed with CH505 SOSIP revealed another elongated epitope, the V2V5 corridor, extending from V2 to V5. Overall, the VSVENV probe identified bNAb lineages with neutralizing IgG and IgA members targeting distinct sites of HIV-1 Env vulnerability. VSV-displayed HIV-1 envelope trimers identified five HIV-1 bNAbs BCR repertoires identified two bNAb lineages class-switched to both IgG and IgA The V3 crown-targeting bNAb M4008_N1 conferred tier 2 virus neutralization Cryo-EM structure of bNAb M1214_N1 with CH505 SOSIP defined a V2V5 corridor epitope
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Affiliation(s)
- Manxue Jia
- Aaron Diamond AIDS Research Center, Affiliate of The Rockefeller University, New York, NY 10016, USA
| | - Rachel A Liberatore
- Laboratory of Retrovirology, The Rockefeller University, New York, NY 10065, USA; Howard Hughes Medical Institute, New York, NY 10016, USA
| | - Yicheng Guo
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Kun-Wei Chan
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - Ruimin Pan
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - Hong Lu
- Aaron Diamond AIDS Research Center, Affiliate of The Rockefeller University, New York, NY 10016, USA
| | - Eric Waltari
- Aaron Diamond AIDS Research Center, Affiliate of The Rockefeller University, New York, NY 10016, USA
| | - Eva Mittler
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Kartik Chandran
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Andrés Finzi
- Centre de Recherche du CHUM and Université de Montréal, Montreal, QC H2X 0A9, Canada
| | - Daniel E Kaufmann
- Centre de Recherche du CHUM and Université de Montréal, Montreal, QC H2X 0A9, Canada; Center for HIV-1/AIDS Vaccine Immunology and Immunogen Discovery (CHAVI-ID), La Jolla, CA 92037, USA
| | - Michael S Seaman
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA
| | - David D Ho
- Aaron Diamond AIDS Research Center, Affiliate of The Rockefeller University, New York, NY 10016, USA
| | - Lawrence Shapiro
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Zizhang Sheng
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Xiang-Peng Kong
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - Paul D Bieniasz
- Laboratory of Retrovirology, The Rockefeller University, New York, NY 10065, USA; Howard Hughes Medical Institute, New York, NY 10016, USA
| | - Xueling Wu
- Aaron Diamond AIDS Research Center, Affiliate of The Rockefeller University, New York, NY 10016, USA.
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22
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Nathan L, Lai AL, Millet JK, Straus MR, Freed JH, Whittaker GR, Daniel S. Calcium Ions Directly Interact with the Ebola Virus Fusion Peptide To Promote Structure-Function Changes That Enhance Infection. ACS Infect Dis 2020; 6:250-260. [PMID: 31746195 DOI: 10.1021/acsinfecdis.9b00296] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ebola virus disease is a serious global health concern given its periodic occurrence, high lethality, and the lack of approved therapeutics. Certain drugs that alter intracellular calcium, particularly in endolysosomes, have been shown to inhibit Ebola virus infection; however, the underlying mechanism is unknown. Here, we provide evidence that Zaire ebolavirus (EBOV) infection is promoted in the presence of calcium as a result of the direct interaction of calcium with the EBOV fusion peptide (FP). We identify the glycoprotein residues D522 and E540 in the FP as functionally critical to EBOV's interaction with calcium. We show using spectroscopic and biophysical assays that interactions of the fusion peptide with Ca2+ ions lead to lipid ordering in the host membrane during membrane fusion, and these changes are promoted at low pH and can be correlated with infectivity. We further demonstrate using circular dichroism spectroscopy that calcium interaction with the fusion peptide promotes α-helical structure of the fusion peptide, a conformational change that enhances membrane fusion, as validated using functional assays of membrane fusion. This study shows that calcium directly targets the Ebola virus fusion peptide and influences its conformation. As these residues are highly conserved across the Filoviridae, calcium's impact on fusion, and subsequently infectivity, is a key interaction that can be leveraged for developing strategies to defend against Ebola infection. This mechanistic insight provides a rationale for the use of calcium-interfering drugs already approved by the FDA as therapeutics against Ebola and enables further development of novel drugs to combat the virus.
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Affiliation(s)
- Lakshmi Nathan
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, 120 Olin Hall, Ithaca, New York 14853, United States
| | - Alex L. Lai
- Baker Laboratory, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Jean Kaoru Millet
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, United States
| | - Marco R. Straus
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, United States
| | - Jack H. Freed
- Baker Laboratory, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Gary R. Whittaker
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, United States
| | - Susan Daniel
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, 120 Olin Hall, Ithaca, New York 14853, United States
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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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24
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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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25
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Li Z, Fan Y, Wei J, Mei X, He Q, Zhang Y, Li T, Long M, Chen J, Bao J, Pan G, Li C, Zhou Z. Baculovirus Utilizes Cholesterol Transporter NIEMANN-Pick C1 for Host Cell Entry. Front Microbiol 2019; 10:2825. [PMID: 31866985 PMCID: PMC6906155 DOI: 10.3389/fmicb.2019.02825] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 11/21/2019] [Indexed: 01/31/2023] Open
Abstract
The dual roles of baculovirus for the control of natural insect populations as an insecticide, and as a tool for foreign gene expression and delivery, have called for a comprehensive understanding of the molecular mechanisms governing viral infection. Here, we demonstrate that the Bombyx mori Niemann-Pick C1 (BmNPC1) is essential for baculovirus infection in insect cells. Both pretreatment of B. mori embryonic cells (BmE) with NPC1 antagonists (imipramine or U18666A) and down-regulation of NPC1 expression resulted in a significant reduction in baculovirus BmNPV (B. mori nuclear polyhedrosis virus) infectivity. Disruption of BmNPC1 could decrease viral entry (2 hpi) rather than reduce the viral binding to the BmE cells. Furthermore, our results showed that NPC1 domain C binds directly and specifically to the viral glycoprotein GP64, which is responsible for both receptor binding and fusion. Antibody blocking assay also revealed that the domain C specific polyclonal antibody inhibited BmNPV infection, indicating that NPC1 domain C most likely plays a role during viral fusion in endosomal compartments. Our results, combined with previous studies identifying an essential role of human NPC1 (hNPC1) in filovirus infection, suggest that the glycoprotein of several enveloped viruses possess a shared strategy of exploiting host NPC1 proteins during virus intracellular entry events.
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Affiliation(s)
- Zhihong Li
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Department of Microbiology, Guizhou University of Traditional Chinese Medicine, Guiyang, China
| | - Youpeng Fan
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Chongqing Key Laboratory of Microsporidia Infection and Control, Southwest University, Chongqing, China
| | - Junhong Wei
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Chongqing Key Laboratory of Microsporidia Infection and Control, Southwest University, Chongqing, China
- Key Laboratory for Sericulture Functional Genomics Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China
| | - Xionge Mei
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Qiang He
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Chongqing Key Laboratory of Microsporidia Infection and Control, Southwest University, Chongqing, China
| | - Yonghua Zhang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
| | - Tian Li
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Chongqing Key Laboratory of Microsporidia Infection and Control, Southwest University, Chongqing, China
- Key Laboratory for Sericulture Functional Genomics Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China
| | - Mengxian Long
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Chongqing Key Laboratory of Microsporidia Infection and Control, Southwest University, Chongqing, China
- Key Laboratory for Sericulture Functional Genomics Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China
| | - Jie Chen
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Chongqing Key Laboratory of Microsporidia Infection and Control, Southwest University, Chongqing, China
- Key Laboratory for Sericulture Functional Genomics Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China
| | - Jialing Bao
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Chongqing Key Laboratory of Microsporidia Infection and Control, Southwest University, Chongqing, China
- Key Laboratory for Sericulture Functional Genomics Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China
| | - Guoqing Pan
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Chongqing Key Laboratory of Microsporidia Infection and Control, Southwest University, Chongqing, China
- Key Laboratory for Sericulture Functional Genomics Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China
| | - Chunfeng Li
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Chongqing Key Laboratory of Microsporidia Infection and Control, Southwest University, Chongqing, China
- Key Laboratory for Sericulture Functional Genomics Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China
| | - Zeyang Zhou
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Chongqing Key Laboratory of Microsporidia Infection and Control, Southwest University, Chongqing, China
- Key Laboratory for Sericulture Functional Genomics Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China
- College of Life Sciences, Chongqing Normal University, Chongqing, China
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26
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Murin CD, Bruhn JF, Bornholdt ZA, Copps J, Stanfield R, Ward AB. Structural Basis of Pan-Ebolavirus Neutralization by an Antibody Targeting the Glycoprotein Fusion Loop. Cell Rep 2019; 24:2723-2732.e4. [PMID: 30184505 DOI: 10.1016/j.celrep.2018.08.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 07/11/2018] [Accepted: 08/06/2018] [Indexed: 12/18/2022] Open
Abstract
Monoclonal antibodies (mAbs) with pan-ebolavirus cross-reactivity are highly desirable, but development of such mAbs is limited by a lack of a molecular understanding of cross-reactive epitopes. The antibody ADI-15878 was previously identified from a human survivor of Ebola virus Makona variant (EBOV/Mak) infection. This mAb demonstrated potent neutralizing activity against all known ebolaviruses and provided protection in rodent and ferret models against three ebolavirus species. Here, we describe the unliganded crystal structure of ADI-15878 as well as the cryo-EM structures of ADI-15878 in complex with the EBOV/Mak and Bundibugyo virus (BDBV) glycoproteins (GPs). ADI-15878 binds through an induced-fit mechanism by targeting highly conserved residues in the internal fusion loop (IFL), bridging across GP protomers via the heptad repeat 1 (HR1) region. Our structures provide a more complete description of the ebolavirus immunogenic landscape, as well as a molecular basis for how rare but potent antibodies target conserved filoviral fusion machinery.
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Affiliation(s)
- Charles D Murin
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Jessica F Bruhn
- Laboratory of Genetics and Helmsley Center for Genomic Medicine, The Salk Institute for Biological Sciences, La Jolla, CA 92037, USA
| | | | - Jeffrey Copps
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Robyn Stanfield
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Andrew B Ward
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
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27
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The Major Hurdle for Effective Baculovirus Transduction into Mammalian Cells Is Passing Early Endosomes. J Virol 2019; 93:JVI.00709-19. [PMID: 31092570 DOI: 10.1128/jvi.00709-19] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 05/07/2019] [Indexed: 12/19/2022] Open
Abstract
Baculoviruses, although they infect insects in nature, can transduce a wide variety of mammalian cells and are therefore promising gene therapy vectors. However, baculovirus transduction into many mammalian cells is very inefficient, and the limiting stages and factors remain unknown. An important finding is that a short-duration trigger with low pH can significantly enhance virus transduction efficiency, but the mechanism is poorly understood. Herein, we performed a detailed comparative study on entry mechanisms of the prototypical baculovirus Autographa californica multiple nucleopolyhedrovirus (AcMNPV) into insect and mammalian cells. The results showed that AcMNPV could be internalized into mammalian cells efficiently, but fusion in early endosomes (EEs) appeared to be the major obstacle. Measurement of endosomal pH suggested that virus fusion might be restricted under relatively high-pH conditions in mammalian cells. Interestingly, mutations of the major viral fusion protein GP64 that conferred decreased fusogenicity did not affect virus infection of insect cells, whereas virus transduction into mammalian cells was severely impaired, suggesting a more stringent dependence on GP64 fusogenicity for AcMNPV entry into mammalian cells than into insect cells. An increase in the fusogenicity of GP64 mutants resulting from low pH triggered the rescue of fusion-deficient recombinant virus transduction efficiency. Based on the above-described findings, the pH of EEs was specifically reduced with a Na+/K+-ATPase inhibitor, and the AcMNPV transduction of many mammalian cells indeed became highly efficient. This study not only revealed the roadblocks to mammalian cell entry of baculovirus but also provides a new strategy for improving baculovirus-based gene delivery and therapy.IMPORTANCE Baculoviruses can transduce a wide variety of mammalian cells but do so with low efficiency, which greatly limits their practical application as potential gene delivery vectors. So far, the understanding of baculovirus entry into mammalian cells is obscure, and the limiting stages and factors are unclear. In this study, by comparatively analyzing the mechanisms of baculovirus entry into mammalian and insect cells, virus fusion during the early stage of endocytosis was revealed as the major obstacle for efficient baculovirus transduction into mammalian cells. A higher fusogenicity of the major viral fusion protein GP64 was found to be required for virus entry into mammalian cells than for entry into insect cells. Interestingly, by decreasing the pH of early endosomes with a specific agent, virus transduction of a wide range of mammalian cells was greatly enhanced. This study uncovers the roadblocks to mammalian cell entry of baculoviruses and presents mechanisms to overcome the roadblocks.
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28
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A Hyperstabilizing Mutation in the Base of the Ebola Virus Glycoprotein Acts at Multiple Steps To Abrogate Viral Entry. mBio 2019; 10:mBio.01408-19. [PMID: 31289183 PMCID: PMC6747718 DOI: 10.1128/mbio.01408-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ebola virus (EBOV) causes highly lethal disease outbreaks against which no FDA-approved countermeasures are available. Although many host factors exploited by EBOV for cell entry have been identified, including host cell surface phosphatidylserine receptors, endosomal cysteine proteases, and the lysosomal cholesterol trafficking protein NPC1, key questions remain. Specifically, late entry steps culminating in viral membrane fusion remain enigmatic. Here, we investigated a set of glycoprotein (GP) mutants previously hypothesized to be entry defective and identified one mutation, R64A, that abolished infection with no apparent impact on GP expression, folding, or viral incorporation. R64A profoundly thermostabilized EBOV GP and rendered it highly resistant to proteolysis in vitro Forward-genetics and cell entry studies strongly suggested that R64A's effects on GP thermostability and proteolysis arrest viral entry at least at two distinct steps: the first upstream of NPC1 binding and the second at a late entry step downstream of fusion activation. Concordantly, toremifene, a small-molecule entry inhibitor previously shown to bind and destabilize GP, may selectively enhance the infectivity of viral particles bearing GP(R64A) at subinhibitory concentrations. R64A provides a valuable tool to further define the interplay between GP stability, proteolysis, and viral membrane fusion; to explore the rational design of stability-modulating antivirals; and to spur the development of next-generation Ebola virus vaccines with improved stability.IMPORTANCE Ebola virus is a medically relevant virus responsible for outbreaks of severe disease in western and central Africa, with mortality rates reaching as high as 90%. Despite considerable effort, there are currently no FDA-approved therapeutics or targeted interventions available, highlighting the need of development in this area. Host-cell invasion represents an attractive target for antivirals, and several drug candidates have been identified; however, our limited understanding of the complex viral entry process challenges the development of such entry-targeting drugs. Here, we report on a glycoprotein mutation that abrogates viral entry and provides insights into the final steps of this process. In addition, the hyperstabilized phenotype of this mutant makes it useful as a tool in the discovery and design of stability-modulating antivirals and next-generation vaccines against Ebola virus.
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29
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Fénéant L, Szymańska-de Wijs KM, Nelson EA, White JM. An exploration of conditions proposed to trigger the Ebola virus glycoprotein for fusion. PLoS One 2019; 14:e0219312. [PMID: 31276481 PMCID: PMC6611598 DOI: 10.1371/journal.pone.0219312] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 06/20/2019] [Indexed: 01/06/2023] Open
Abstract
Ebolaviruses continue to inflict horrific disease and instill fear. The 2013-2016 outbreak in Western Africa caused unfathomable morbidity and mortality (over 11,000 deaths), and the second largest outbreak is on-going in the Democratic Republic of the Congo. The first stage of an Ebolavirus infection is entry, culminating in delivery of the viral genome into the cytoplasm to initiate replication. Among enveloped viruses, Ebolaviruses use a complex entry pathway: they bind to attachment factors on cell surfaces, are engulfed by macropinocytosis, and traffic through the endosomal system. En route, the receptor binding subunit of the glycoprotein (GP) is reduced from ~130 to ~19 kDa by cathepsins. This event allows cleaved GP (GPcl) to bind to Niemann-Pick C1 (NPC1), its endosomal receptor. The virus then fuses with a late endosomal membrane, but how this occurs remains a subject of debate. An early, but standing, observation is that entry of particles bearing GPcl is inhibited by agents that raise endosomal pH or inhibit cysteine proteases, suggesting the need for an additional factor(s). Yet, some have concluded that NPC1 is sufficient to trigger the fusion activity of GPcl. Here, we re-examined this question using sensitive cell-cell and pseudovirus-cell fusion assays. We did not observe detectable GPcl-mediated fusion with NPC1 or its GPcl binding domain at any pH tested, while robust fusion was consistently observed with GP from lymphocytic choriomeningitis virus at low pH. Addition of proposed fusion-enhancing factors-cations (Ca++ and K+), a reducing agent, the anionic lipid Bis(Monoacylglycero)Phosphate, and a mixture of cathepsins B and L-did not induce detectable fusion. Our findings are in line with the earlier proposal that an additional factor is required to trigger the full fusion activity of GPcl after binding to NPC1. We discuss caveats to our study and what the missing factor(s) might be.
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Affiliation(s)
- Lucie Fénéant
- Department of Cell Biology, University of Virginia, Charlottesville, Virginia, United States of America
| | | | - Elizabeth A. Nelson
- Department of Cell Biology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Judith M. White
- Department of Cell Biology, University of Virginia, Charlottesville, Virginia, United States of America
- Department of Microbiology, University of Virginia, Charlottesville, Virginia, United States of America
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Hu L, Li Y, Deng F, Hu Z, Wang H, Wang M. Improving Baculovirus Transduction of Mammalian Cells by Incorporation of Thogotovirus Glycoproteins. Virol Sin 2019; 34:454-466. [PMID: 31201733 DOI: 10.1007/s12250-019-00133-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Accepted: 04/09/2019] [Indexed: 12/19/2022] Open
Abstract
Baculovirus can transduce a wide range of mammalian cells and is considered a promising gene therapy vector. However, the low transduction efficiency of baculovirus into many mammalian cells limits its practical application. Co-expressing heterologous viral glycoproteins (GPs), such as vesicular stomatitis virus G protein (VSV G), with baculovirus native envelope protein GP64 is one of the feasible strategies for improving virus transduction. Tick-borne thogotoviruses infect mammals and their GPs share sequence/structure homology and common evolutionary origins with baculovirus GP64. Herein, we tested whether thogotovirus GPs could facilitate the entry of the prototype baculovirus Autographa californica multiple multiple nucleopolyhedrovirus (AcMNPV) into mammalian cells. The gp genes of two thogotoviruses, Thogoto virus and Dhori virus, were inserted into the AcMNPV genome. Both GPs were properly expressed and incorporated into the envelope of the recombinant AcMNPVs. The transduction rates of recombinant AcMNPVs expressing the two thogotovirus GPs increased for approximately 4-12 fold compared to the wild type AcMNPV in six of the 12 tested mammalian cell lines. It seemed that thogotovirus GPs provide the recombinant AcMNPVs with different cell tropisms and showed better performance in several mammalian cells compared to VSV G incorporated AcMNPV. Further studies showed that the improved transduction was a result of augmented virus-endosome fusion and endosome escaping, rather than increased cell binding or internalization. We found the AcMNPV envelope protein GP64-mediated fusion was enhanced by the thogotovirus GPs at relatively higher pH conditions. Therefore, the thogotovirus GPs represent novel candidates to improve baculovirus-based gene delivery vectors.
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Affiliation(s)
- Liangbo Hu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
- University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Yimeng Li
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
- University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Fei Deng
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Zhihong Hu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Hualin Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China.
| | - Manli Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China.
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31
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Arbidol and Other Low-Molecular-Weight Drugs That Inhibit Lassa and Ebola Viruses. J Virol 2019; 93:JVI.02185-18. [PMID: 30700611 DOI: 10.1128/jvi.02185-18] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 01/22/2019] [Indexed: 02/08/2023] Open
Abstract
Antiviral therapies that impede virus entry are attractive because they act on the first phase of the infectious cycle. Drugs that target pathways common to multiple viruses are particularly desirable when laboratory-based viral identification may be challenging, e.g., in an outbreak setting. We are interested in identifying drugs that block both Ebola virus (EBOV) and Lassa virus (LASV), two unrelated but highly pathogenic hemorrhagic fever viruses that have caused outbreaks in similar regions in Africa and share features of virus entry: use of cell surface attachment factors, macropinocytosis, endosomal receptors, and low pH to trigger fusion in late endosomes. Toward this goal, we directly compared the potency of eight drugs known to block EBOV entry with their potency as inhibitors of LASV entry. Five drugs (amodiaquine, apilimod, arbidol, niclosamide, and zoniporide) showed roughly equivalent degrees of inhibition of LASV and EBOV glycoprotein (GP)-bearing pseudoviruses; three (clomiphene, sertraline, and toremifene) were more potent against EBOV. We then focused on arbidol, which is licensed abroad as an anti-influenza drug and exhibits activity against a diverse array of clinically relevant viruses. We found that arbidol inhibits infection by authentic LASV, inhibits LASV GP-mediated cell-cell fusion and virus-cell fusion, and, reminiscent of its activity on influenza virus hemagglutinin, stabilizes LASV GP to low-pH exposure. Our findings suggest that arbidol inhibits LASV fusion, which may partly involve blocking conformational changes in LASV GP. We discuss our findings in terms of the potential to develop a drug cocktail that could inhibit both LASV and EBOV.IMPORTANCE Lassa and Ebola viruses continue to cause severe outbreaks in humans, yet there are only limited therapeutic options to treat the deadly hemorrhagic fever diseases they cause. Because of overlapping geographic occurrences and similarities in mode of entry into cells, we seek a practical drug or drug cocktail that could be used to treat infections by both viruses. Toward this goal, we directly compared eight drugs, approved or in clinical testing, for the ability to block entry mediated by the glycoproteins of both viruses. We identified five drugs with approximately equal potencies against both. Among these, we investigated the modes of action of arbidol, a drug licensed abroad to treat influenza infections. We found, as shown for influenza virus, that arbidol blocks fusion mediated by the Lassa virus glycoprotein. Our findings encourage the development of a combination of approved drugs to treat both Lassa and Ebola virus diseases.
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Liu J, Xu M, Tang B, Hu L, Deng F, Wang H, Pang DW, Hu Z, Wang M, Zhou Y. Single-Particle Tracking Reveals the Sequential Entry Process of the Bunyavirus Severe Fever with Thrombocytopenia Syndrome Virus. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1803788. [PMID: 30589216 DOI: 10.1002/smll.201803788] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 11/24/2018] [Indexed: 06/09/2023]
Abstract
The Bunyavirales is one of the largest groups of RNA viruses, which encompasses many strains that are highly pathogenic to animals and humans. Severe fever with thrombocytopenia syndrome virus (SFTSV) is an emerging tick-borne bunyavirus that causes severe disease in humans, with a high fatality rate of up to 30%. To date, the entry process of bunyavirus infection remains obscure. Here, using quantum dot (QD)-based single-particle tracking and multicolor imaging, the dynamic molecular process of SFTSV entry and penetration is systematically dissected. The results show that internalization of SFTSV into host cells is initiated by recruiting clathrin onto the cell membrane for the formation of clathrin-coated pits and further pinching off from the plasma membrane to form discrete vesicles. These vesicular carriers further deliver virions to Rab5+ early endosomes, and then to Rab7+ late endosomes. The intracellular transport of virion-carrying endocytic vesicles is dependent first on actin filaments at the cell periphery, and then on microtubules toward the cell interior. The final fusion events occur at ≈15-60 min post-entry, and are triggered by the acidic environment at ≈pH5.6 within the late endosomes. These results reveal the multistep SFTSV entry process and the dynamic virus-host interactions involved.
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Affiliation(s)
- Jia Liu
- Department of Forensic Medicine, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Mingyue Xu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Bo Tang
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, State Key Laboratory of Virology, and The Institute of Advanced Studies, Wuhan University, Wuhan, 430072, China
| | - Liangbo Hu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Fei Deng
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Hualin Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Dai-Wen Pang
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, State Key Laboratory of Virology, and The Institute of Advanced Studies, Wuhan University, Wuhan, 430072, China
| | - Zhihong Hu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Manli Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Yiwu Zhou
- Department of Forensic Medicine, Tongji Medical College of Huazhong University of Science and Technology, Wuhan, 430030, China
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Spence JS, He R, Hoffmann HH, Das T, Thinon E, Rice CM, Peng T, Chandran K, Hang HC. IFITM3 directly engages and shuttles incoming virus particles to lysosomes. Nat Chem Biol 2019; 15:259-268. [PMID: 30643282 PMCID: PMC6466627 DOI: 10.1038/s41589-018-0213-2] [Citation(s) in RCA: 150] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 12/03/2018] [Indexed: 12/16/2022]
Abstract
Interferon-induced transmembrane proteins (IFITMs 1, 2 and 3) have emerged as important innate immune effectors that prevent diverse virus infections in vertebrates. However, the cellular mechanisms and live-cell imaging of these small membrane proteins have been challenging to evaluate during viral entry of mammalian cells. Using CRISPR–Cas9-mediated IFITM-mutant cell lines, we demonstrate that human IFITM1, IFITM2 and IFITM3 act cooperatively and function in a dose-dependent fashion in interferon-stimulated cells. Through site-specific fluorophore tagging and live-cell imaging studies, we show that IFITM3 is on endocytic vesicles that fuse with incoming virus particles and enhances the trafficking of this pathogenic cargo to lysosomes. IFITM3 trafficking is specific to restricted viruses, requires S-palmitoylation and is abrogated with loss-of-function mutants. The site-specific protein labeling and live-cell imaging approaches described here should facilitate the functional analysis of host factors involved in pathogen restriction as well as their mechanisms of regulation. Live-cell imaging and virus trafficking studies show that the host innate immune receptor IFITM3 localizes with endocytic vesicles that fuse with incoming viruses to ultimately enhance their traffic to lysosomes.![]()
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Affiliation(s)
- Jennifer S Spence
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Ruina He
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, NY, USA
| | - Hans-Heinrich Hoffmann
- Laboratory of Virology and Infectious Disease, Center for the Study of Hepatitis C, The Rockefeller University, New York, NY, USA
| | - Tandrila Das
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, NY, USA
| | - Emmanuelle Thinon
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, NY, USA
| | - Charles M Rice
- Laboratory of Virology and Infectious Disease, Center for the Study of Hepatitis C, The Rockefeller University, New York, NY, USA
| | - Tao Peng
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, NY, USA. .,School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China.
| | - Kartik Chandran
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA.
| | - Howard C Hang
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, NY, USA.
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34
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Nathan L, Daniel S. Single Virion Tracking Microscopy for the Study of Virus Entry Processes in Live Cells and Biomimetic Platforms. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1215:13-43. [PMID: 31317494 PMCID: PMC7122913 DOI: 10.1007/978-3-030-14741-9_2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The most widely-used assays for studying viral entry, including infectivity, cofloatation, and cell-cell fusion assays, yield functional information but provide low resolution of individual entry steps. Structural characterization provides high-resolution conformational information, but on its own is unable to address the functional significance of these conformations. Single virion tracking microscopy techniques provide more detail on the intermediate entry steps than infection assays and more functional information than structural methods, bridging the gap between these methods. In addition, single virion approaches also provide dynamic information about the kinetics of entry processes. This chapter reviews single virion tracking techniques and describes how they can be applied to study specific virus entry steps. These techniques provide information complementary to traditional ensemble approaches. Single virion techniques may either probe virion behavior in live cells or in biomimetic platforms. Synthesizing information from ensemble, structural, and single virion techniques ultimately yields a more complete understanding of the viral entry process than can be achieved by any single method alone.
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Affiliation(s)
- Lakshmi Nathan
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, USA.
| | - Susan Daniel
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, USA.
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35
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Warfield KL, Howell KA, Vu H, Geisbert J, Wong G, Shulenin S, Sproule S, Holtsberg FW, Leung DW, Amarasinghe GK, Swenson DL, Bavari S, Kobinger GP, Geisbert TW, Aman MJ. Role of Antibodies in Protection Against Ebola Virus in Nonhuman Primates Immunized With Three Vaccine Platforms. J Infect Dis 2018; 218:S553-S564. [PMID: 29939318 PMCID: PMC6249597 DOI: 10.1093/infdis/jiy316] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Background Several vaccine platforms have been successfully evaluated for prevention of Ebola virus (EBOV) disease (EVD) in nonhuman primates and humans. Despite remarkable efficacy by multiple vaccines, the immunological correlates of protection against EVD are incompletely understood. Methods We systematically evaluated the antibody response to various EBOV proteins in 79 nonhuman primates vaccinated with various EBOV vaccine platforms. We evaluated the serum immunoglobulin (Ig)G titers against EBOV glycoprotein (GP), the ability of the vaccine-induced antibodies to bind GP at acidic pH or to displace ZMapp, and virus neutralization titers. The correlation of these outcomes with survival from EVD was evaluated by appropriate statistical methods. Results Irrespective of the vaccine platform, protection from EVD strongly correlated with anti-GP IgG titers. The GP-directed antibody levels required for protection in animals vaccinated with virus-like particles (VLPs) lacking nucleoprotein (NP) was significantly higher than animals immunized with NP-containing VLPs or adenovirus-expressed GP, platforms that induce strong T-cell responses. Furthermore, protective immune responses correlated with anti-GP antibody binding strength at acidic pH, neutralization of GP-expressing pseudovirions, and the ability to displace ZMapp components from GP. Conclusions These findings suggest key quantitative and qualitative attributes of antibody response to EVD vaccines as potential correlates of protection.
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Affiliation(s)
| | | | - Hong Vu
- Integrated BioTherapeutics Inc., Rockville, Maryland
| | | | - Gary Wong
- Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba
| | | | | | | | - Daisy W Leung
- Departments of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri
| | - Gaya K Amarasinghe
- Departments of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri
| | - Dana L Swenson
- US Army Medical Research Institute of Infectious Diseases, Frederick, Maryland
| | - Sina Bavari
- US Army Medical Research Institute of Infectious Diseases, Frederick, Maryland
| | - Gary P Kobinger
- Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba
| | | | - M Javad Aman
- Integrated BioTherapeutics Inc., Rockville, Maryland
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36
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Goldstein T, Anthony SJ, Gbakima A, Bird BH, Bangura J, Tremeau-Bravard A, Belaganahalli MN, Wells HL, Dhanota JK, Liang E, Grodus M, Jangra RK, DeJesus VA, Lasso G, Smith BR, Jambai A, Kamara BO, Kamara S, Bangura W, Monagin C, Shapira S, Johnson CK, Saylors K, Rubin EM, Chandran K, Lipkin WI, Mazet JAK. The discovery of Bombali virus adds further support for bats as hosts of ebolaviruses. Nat Microbiol 2018; 3:1084-1089. [PMID: 30150734 PMCID: PMC6557442 DOI: 10.1038/s41564-018-0227-2] [Citation(s) in RCA: 218] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 07/25/2018] [Indexed: 11/08/2022]
Abstract
Here we describe the complete genome of a new ebolavirus, Bombali virus (BOMV) detected in free-tailed bats in Sierra Leone (little free-tailed (Chaerephon pumilus) and Angolan free-tailed (Mops condylurus)). The bats were found roosting inside houses, indicating the potential for human transmission. We show that the viral glycoprotein can mediate entry into human cells. However, further studies are required to investigate whether exposure has actually occurred or if BOMV is pathogenic in humans.
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Affiliation(s)
- Tracey Goldstein
- One Health Institute & Karen C. Drayer Wildlife Health Center, School of Veterinary Medicine, University of California, Davis, CA, USA.
| | - Simon J Anthony
- Center for Infection and Immunity, Mailman School of Public Health, Columbia University, New York, NY, USA.
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY, USA.
- EcoHealth Alliance, New York, NY, USA.
| | - Aiah Gbakima
- Metabiota, Inc. Sierra Leone, Freetown, Sierra Leone
| | - Brian H Bird
- One Health Institute & Karen C. Drayer Wildlife Health Center, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - James Bangura
- Metabiota, Inc. Sierra Leone, Freetown, Sierra Leone
| | - Alexandre Tremeau-Bravard
- One Health Institute & Karen C. Drayer Wildlife Health Center, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Manjunatha N Belaganahalli
- One Health Institute & Karen C. Drayer Wildlife Health Center, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Heather L Wells
- Center for Infection and Immunity, Mailman School of Public Health, Columbia University, New York, NY, USA
| | - Jasjeet K Dhanota
- One Health Institute & Karen C. Drayer Wildlife Health Center, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Eliza Liang
- Center for Infection and Immunity, Mailman School of Public Health, Columbia University, New York, NY, USA
- EcoHealth Alliance, New York, NY, USA
| | - Michael Grodus
- Center for Infection and Immunity, Mailman School of Public Health, Columbia University, New York, NY, USA
| | - Rohit K Jangra
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, USA
| | - Veronica A DeJesus
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, USA
| | - Gorka Lasso
- Department of Systems Biology, Irving Cancer Research Center, Columbia University, New York, NY, USA
| | - Brett R Smith
- One Health Institute & Karen C. Drayer Wildlife Health Center, School of Veterinary Medicine, University of California, Davis, CA, USA
| | - Amara Jambai
- Ministry of Health and Sanitation, Freetown, Sierra Leone
| | | | - Sorie Kamara
- Livestock and Veterinary Services Division, Ministry of Agriculture, Forestry and Food Security, Freetown, Sierra Leone
| | - William Bangura
- Forestry and Wildlife Division, Ministry of Agriculture, Forestry and Food Security, Freetown, Sierra Leone
| | - Corina Monagin
- One Health Institute & Karen C. Drayer Wildlife Health Center, School of Veterinary Medicine, University of California, Davis, CA, USA
- Metabiota, Inc., San Francisco, CA, USA
| | - Sagi Shapira
- Department of Systems Biology, Irving Cancer Research Center, Columbia University, New York, NY, USA
- Department of Microbiology & Immunology, Columbia University, New York, NY, USA
| | - Christine K Johnson
- One Health Institute & Karen C. Drayer Wildlife Health Center, School of Veterinary Medicine, University of California, Davis, CA, USA
| | | | | | - Kartik Chandran
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, USA
| | - W Ian Lipkin
- Center for Infection and Immunity, Mailman School of Public Health, Columbia University, New York, NY, USA
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY, USA
| | - Jonna A K Mazet
- One Health Institute & Karen C. Drayer Wildlife Health Center, School of Veterinary Medicine, University of California, Davis, CA, USA
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37
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Gilchuk P, Kuzmina N, Ilinykh PA, Huang K, Gunn BM, Bryan A, Davidson E, Doranz BJ, Turner HL, Fusco ML, Bramble MS, Hoff NA, Binshtein E, Kose N, Flyak AI, Flinko R, Orlandi C, Carnahan R, Parrish EH, Sevy AM, Bombardi RG, Singh PK, Mukadi P, Muyembe-Tamfum JJ, Ohi MD, Saphire EO, Lewis GK, Alter G, Ward AB, Rimoin AW, Bukreyev A, Crowe JE. Multifunctional Pan-ebolavirus Antibody Recognizes a Site of Broad Vulnerability on the Ebolavirus Glycoprotein. Immunity 2018; 49:363-374.e10. [PMID: 30029854 PMCID: PMC6104738 DOI: 10.1016/j.immuni.2018.06.018] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Revised: 05/19/2018] [Accepted: 06/28/2018] [Indexed: 01/14/2023]
Abstract
Ebolaviruses cause severe disease in humans, and identification of monoclonal antibodies (mAbs) that are effective against multiple ebolaviruses are important for therapeutics development. Here we describe a distinct class of broadly neutralizing human mAbs with protective capacity against three ebolaviruses infectious for humans: Ebola (EBOV), Sudan (SUDV), and Bundibugyo (BDBV) viruses. We isolated mAbs from human survivors of ebolavirus disease and identified a potent mAb, EBOV-520, which bound to an epitope in the glycoprotein (GP) base region. EBOV-520 efficiently neutralized EBOV, BDBV, and SUDV and also showed protective capacity in relevant animal models of these infections. EBOV-520 mediated protection principally by direct virus neutralization and exhibited multifunctional properties. This study identified a potent naturally occurring mAb and defined key features of the human antibody response that may contribute to broad protection. This multifunctional mAb and related clones are promising candidates for development as broadly protective pan-ebolavirus therapeutic molecules.
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Affiliation(s)
- Pavlo Gilchuk
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Natalia Kuzmina
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA,Galveston National Laboratory, Galveston, TX 77550, USA
| | - Philipp A. Ilinykh
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA,Galveston National Laboratory, Galveston, TX 77550, USA
| | - Kai Huang
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA,Galveston National Laboratory, Galveston, TX 77550, USA
| | - Bronwyn M. Gunn
- Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA 02139, USA
| | - Aubrey Bryan
- Integral Molecular, Inc., Philadelphia, PA 19104, USA
| | | | | | - Hannah L. Turner
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Marnie L. Fusco
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Matthew S. Bramble
- Department of Epidemiology, Jonathan and Karin Fielding School of Public Health, University of California, Los Angeles, Los Angeles, CA 90095, USA,Department of Genetic Medicine Research, Children’s Research Institute, Children’s National Medical Center, Washington, DC 20010, USA
| | - Nicole A. Hoff
- Department of Epidemiology, Jonathan and Karin Fielding School of Public Health, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Elad Binshtein
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Nurgun Kose
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Andrew I. Flyak
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Robin Flinko
- Division of Vaccine Research, Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Chiara Orlandi
- Division of Vaccine Research, Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Robert Carnahan
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Erica H. Parrish
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Alexander M. Sevy
- Chemical and Physical Biology Program, Vanderbilt University, Nashville, TN 37232, USA
| | - Robin G. Bombardi
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Prashant K. Singh
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Patrick Mukadi
- Institut Nationale de Recherche Biomédicale, Kinshasa, Democratic Republic of the Congo
| | | | - Melanie D. Ohi
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Erica Ollmann Saphire
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA,Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA,The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - George K. Lewis
- Division of Vaccine Research, Institute of Human Virology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Galit Alter
- Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA 02139, USA
| | - Andrew B. Ward
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Anne W. Rimoin
- Department of Epidemiology, Jonathan and Karin Fielding School of Public Health, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Alexander Bukreyev
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA,Galveston National Laboratory, Galveston, TX 77550, USA,Department of Microbiology & Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA,Corresponding author
| | - James E. Crowe
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA,Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA,Chemical and Physical Biology Program, Vanderbilt University, Nashville, TN 37232, USA,Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA,Corresponding author
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Ilinykh PA, Santos RI, Gunn BM, Kuzmina NA, Shen X, Huang K, Gilchuk P, Flyak AI, Younan P, Alter G, Crowe JE, Bukreyev A. Asymmetric antiviral effects of ebolavirus antibodies targeting glycoprotein stem and glycan cap. PLoS Pathog 2018; 14:e1007204. [PMID: 30138408 PMCID: PMC6107261 DOI: 10.1371/journal.ppat.1007204] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 07/08/2018] [Indexed: 01/24/2023] Open
Abstract
Recent studies suggest that some monoclonal antibodies (mAbs) specific for ebolavirus glycoprotein (GP) can protect experimental animals against infections. Most mAbs isolated from ebolavirus survivors appeared to target the glycan cap or the stalk region of the viral GP, which is the envelope protein and the only antigen inducing virus-neutralizing antibody response. Some of the mAbs were demonstrated to be protective in vivo. Here, a panel of mAbs from four individual survivors of ebolavirus infection that target the glycan cap or stem region were selected for investigation of the mechanisms of their antiviral effect. Comparative characterization of the inhibiting effects on multiple steps of viral replication was performed, including attachment, post-attachment, entry, binding at low pH, post-cleavage neutralization of virions, viral trafficking to endosomes, cell-to-cell transmission, viral egress, and inhibition when added early at various time points post-infection. In addition, Fc-domain related properties were characterized, including activation and degranulation of NK cells, antibody-dependent cellular phagocytosis and glycan content. The two groups of mAbs (glycan cap versus stem) demonstrated very different profiles of activities suggesting usage of mAbs with different epitope specificity could coordinate inhibition of multiple steps of filovirus infection through Fab- and Fc-mediated mechanisms, and provide a reliable therapeutic approach.
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Affiliation(s)
- Philipp A. Ilinykh
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States of America
- Galveston National Laboratory, Galveston, TX, United States of America
| | - Rodrigo I. Santos
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States of America
| | - Bronwyn M. Gunn
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - Natalia A. Kuzmina
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States of America
- Galveston National Laboratory, Galveston, TX, United States of America
| | - Xiaoli Shen
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States of America
- Galveston National Laboratory, Galveston, TX, United States of America
| | - Kai Huang
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States of America
- Galveston National Laboratory, Galveston, TX, United States of America
| | - Pavlo Gilchuk
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - Andrew I. Flyak
- Departments of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - Patrick Younan
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States of America
- Galveston National Laboratory, Galveston, TX, United States of America
| | - Galit Alter
- Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA, United States of America
| | - James E. Crowe
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, United States of America
- Departments of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, United States of America
- Department of Pediatrics (Infectious Diseases), Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - Alexander Bukreyev
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States of America
- Galveston National Laboratory, Galveston, TX, United States of America
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, United States of America
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Abstract
The 2014 western Africa Ebola virus (EBOV) epidemic was unprecedented in magnitude, infecting over 28,000 and causing over 11,000 deaths. During this outbreak, multiple instances of EBOV sexual transmission were reported, including cases where the infectious individual had recovered from EBOV disease months before transmission. Potential human host factors in EBOV sexual transmission remain unstudied. Several basic seminal amyloids, most notably semen-derived enhancer of viral infection (SEVI), enhance in vitro infection by HIV and several other viruses. To test the ability of these peptides to enhance EBOV infection, viruses bearing the EBOV glycoprotein (EboGP) were preincubated with physiological concentrations of SEVI before infection of physiologically relevant cell lines and primary cells. Preincubation with SEVI significantly increased EboGP-mediated infectivity and replication in epithelium- and monocyte-derived cell lines. This enhancement was dependent upon amyloidogenesis and positive charge, and infection results were observed with both viruses carrying EboGP and authentic EBOV as well as with semen. SEVI enhanced binding of virus to cells and markedly increased its subsequent internalization. SEVI also stimulated uptake of a fluid phase marker by macropinocytosis, a critical mechanism by which cells internalize EBOV. We report a previously unrecognized ability of SEVI and semen to significantly alter viral physical properties critical for transmissibility by increasing the stability of EboGP-bearing recombinant viruses during incubation at elevated temperature and providing resistance to desiccation. Given the potential for EBOV sexual transmission to spark new transmission chains, these findings represent an important interrogation of factors potentially important for this EBOV transmission route.
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40
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Shrivastava-Ranjan P, Flint M, Bergeron É, McElroy AK, Chatterjee P, Albariño CG, Nichol ST, Spiropoulou CF. Statins Suppress Ebola Virus Infectivity by Interfering with Glycoprotein Processing. mBio 2018; 9:e00660-18. [PMID: 29717011 PMCID: PMC5930306 DOI: 10.1128/mbio.00660-18] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 03/27/2018] [Indexed: 12/18/2022] Open
Abstract
Ebola virus (EBOV) infection is a major public health concern due to high fatality rates and limited effective treatments. Statins, widely used cholesterol-lowering drugs, have pleiotropic mechanisms of action and were suggested as potential adjunct therapy for Ebola virus disease (EVD) during the 2013-2016 outbreak in West Africa. Here, we evaluated the antiviral effects of statin (lovastatin) on EBOV infection in vitro Statin treatment decreased infectious EBOV production in primary human monocyte-derived macrophages and in the hepatic cell line Huh7. Statin treatment did not interfere with viral entry, but the viral particles released from treated cells showed reduced infectivity due to inhibition of viral glycoprotein processing, as evidenced by decreased ratios of the mature glycoprotein form to precursor form. Statin-induced inhibition of infectious virus production and glycoprotein processing was reversed by exogenous mevalonate, the rate-limiting product of the cholesterol biosynthesis pathway, but not by low-density lipoprotein. Finally, statin-treated cells produced EBOV particles devoid of the surface glycoproteins required for virus infectivity. Our findings demonstrate that statin treatment inhibits EBOV infection and suggest that the efficacy of statin treatment should be evaluated in appropriate animal models of EVD.IMPORTANCE Treatments targeting Ebola virus disease (EVD) are experimental, expensive, and scarce. Statins are inexpensive generic drugs that have been used for many years for the treatment of hypercholesterolemia and have a favorable safety profile. Here, we show the antiviral effects of statins on infectious Ebola virus (EBOV) production. Our study reveals a novel molecular mechanism in which statin regulates EBOV particle infectivity by preventing glycoprotein processing and incorporation into virus particles. Additionally, statins have anti-inflammatory and immunomodulatory effects. Since inflammation and dysregulation of the immune system are characteristic features of EVD, statins could be explored as part of EVD therapeutics.
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Affiliation(s)
- Punya Shrivastava-Ranjan
- Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Mike Flint
- Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Éric Bergeron
- Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Anita K McElroy
- Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
- Division of Pediatric Infectious Disease, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania, USA
| | - Payel Chatterjee
- Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - César G Albariño
- Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Stuart T Nichol
- Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Christina F Spiropoulou
- Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
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41
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Ye M, Lehigh KM, Ginty DD. Multivesicular bodies mediate long-range retrograde NGF-TrkA signaling. eLife 2018; 7:33012. [PMID: 29381137 PMCID: PMC5811214 DOI: 10.7554/elife.33012] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2017] [Accepted: 01/30/2018] [Indexed: 12/25/2022] Open
Abstract
The development of neurons in the peripheral nervous system is dependent on target-derived, long-range retrograde neurotrophic factor signals. The prevailing view is that target-derived nerve growth factor (NGF), the prototypical neurotrophin, and its receptor TrkA are carried retrogradely by early endosomes, which serve as TrkA signaling platforms in cell bodies. Here, we report that the majority of retrograde TrkA signaling endosomes in mouse sympathetic neurons are ultrastructurally and molecularly defined multivesicular bodies (MVBs). In contrast to MVBs that carry non-TrkA cargoes from distal axons to cell bodies, retrogradely transported TrkA+ MVBs that arrive in cell bodies evade lysosomal fusion and instead evolve into TrkA+ single-membrane vesicles that are signaling competent. Moreover, TrkA kinase activity associated with retrogradely transported TrkA+ MVBs determines TrkA+ endosome evolution and fate. Thus, MVBs deliver long-range retrograde NGF signals and serve as signaling and sorting platforms in the cell soma, and MVB cargoes dictate their vesicular fate.
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Affiliation(s)
- Mengchen Ye
- Human Genetics Training Program, The Johns Hopkins University, School of Medicine, Baltimore, United States.,Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, United States
| | - Kathryn M Lehigh
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, United States.,Department of Neuroscience, The Johns Hopkins University, School of Medicine, Baltimore, United States
| | - David D Ginty
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, United States
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42
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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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43
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Sood C, Francis AC, Desai TM, Melikyan GB. An improved labeling strategy enables automated detection of single-virus fusion and assessment of HIV-1 protease activity in single virions. J Biol Chem 2017; 292:20196-20207. [PMID: 29046351 PMCID: PMC5724006 DOI: 10.1074/jbc.m117.818088] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 10/12/2017] [Indexed: 11/06/2022] Open
Abstract
Enveloped viruses transfer their genomes into host cells by fusing their membrane to that of the cell. To visualize single-virus fusion in living cells, researchers take advantage of the proteolytic maturation of HIV, type 1 (HIV-1), which can generate free fluorescent proteins within the viral particle. Co-labeling viruses with a content marker and a fluorescently tagged Vpr (a viral core protein) enables detection of single-virus fusions, but a major limitation of this approach is that not all viral particles incorporate both markers. Here we designed a labeling strategy based on the bifunctional mCherry-2xCL-YFP-Vpr construct, in which 2xCL denotes a tandem cleavage site for the viral protease. This bifunctional marker was efficiently cleaved during virus maturation, producing free mCherry and the core-associated YFP-Vpr. A nearly perfect colocalization of these two markers in virions and their fixed 1:1 ratio enabled automated detection of single-particle fusion in both fixed and live cells based on loss of the mCherry signal. Furthermore, a drop in FRET efficiency between YFP and mCherry because of cleavage of the bifunctional marker, which manifested as a marked shift in the normalized YFP/mCherry fluorescence ratio, reliably predicted viral protease activity in single virions. This feature could discriminate between the particles containing free mCherry, and therefore likely representing mature viruses, and immature particles whose fusion cannot be detected. In summary, our new labeling strategy offers several advantages compared with previous approaches, including increased reliability and throughput of detection of viral fusion. We anticipate that our method will have significant utility for studying viral fusion and maturation.
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Affiliation(s)
- Chetan Sood
- Department of Pediatrics, Emory University, Atlanta, Georgia 30322
| | | | - Tanay M Desai
- Department of Pediatrics, Emory University, Atlanta, Georgia 30322
| | - Gregory B Melikyan
- Department of Pediatrics, Emory University, Atlanta, Georgia 30322; Children's Healthcare of Atlanta, Atlanta, Georgia 30322.
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44
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Qiu S, Leung A, Bo Y, Kozak RA, Anand SP, Warkentin C, Salambanga FDR, Cui J, Kobinger G, Kobasa D, Côté M. Ebola virus requires phosphatidylinositol (3,5) bisphosphate production for efficient viral entry. Virology 2017; 513:17-28. [PMID: 29031163 DOI: 10.1016/j.virol.2017.09.028] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 09/28/2017] [Accepted: 09/30/2017] [Indexed: 12/11/2022]
Abstract
For entry, Ebola virus (EBOV) requires the interaction of its viral glycoprotein with the cellular protein Niemann-Pick C1 (NPC1) which resides in late endosomes and lysosomes. How EBOV is trafficked and delivered to NPC1 and whether this is positively regulated during entry remain unclear. Here, we show that the PIKfyve-ArPIKfyve-Sac3 cellular complex, which is involved in the metabolism of phosphatidylinositol (3,5) bisphosphate (PtdIns(3,5)P2), is critical for EBOV infection. Although the expression of all subunits of the complex was required for efficient entry, PIKfyve kinase activity was specifically critical for entry by all pathogenic filoviruses. Inhibition of PIKfyve prevented colocalization of EBOV with NPC1 and led to virus accumulation in intracellular vesicles with characteristics of early endosomes. Importantly, genetically-encoded phosphoinositide probes revealed an increase in PtdIns(3,5)P2-positive vesicles in cells during EBOV entry. Taken together, our studies suggest that EBOV requires PtdIns(3,5)P2 production in cells to promote efficient delivery to NPC1.
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Affiliation(s)
- Shirley Qiu
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada; Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Canada
| | - Anders Leung
- Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Canada
| | - Yuxia Bo
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada; Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Canada
| | - Robert A Kozak
- Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Canada
| | - Sai Priya Anand
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada; Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Canada
| | - Corina Warkentin
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada; Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Canada
| | - Fabiola D R Salambanga
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada; Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Canada
| | - Jennifer Cui
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada; Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Canada
| | - Gary Kobinger
- Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Canada
| | - Darwyn Kobasa
- Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Canada; Department of Medical Microbiology, University of Manitoba, Winnipeg, Canada
| | - Marceline Côté
- Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada; Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, Canada.
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45
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Hofmann D, Zak SE, Nyakatura EK, Mittler E, Bakken RR, Chandran K, Dye JM, Lai JR. Mechanistic and Fc requirements for inhibition of Sudan virus entry and in vivo protection by a synthetic antibody. Immunol Lett 2017; 190:289-295. [PMID: 28890093 DOI: 10.1016/j.imlet.2017.09.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 08/28/2017] [Accepted: 09/05/2017] [Indexed: 11/18/2022]
Abstract
The Sudan virus (SUDV), an ebolavirus, causes severe hemorrhagic fever with human case fatality rates of ∼50%. Previous work from our lab demonstrated the synthetic antibody F4 potently inhibits viral entry and protects against lethal virus challenge in mice [Chen et al., ACS Chem. Biol., 2014, 9, 2263-2273]. Here, we explore mechanistic requirements as well as contribution of the Fc region and function on neutralization and in vivo protection. Live cell imaging demonstrates that the antibody colocalizes with vesicular stomatitis virus particles containing the Sudan virus glycoprotein (VSV-GPSUDV) and that the antibody is rapidly degraded within cellular endosomes. A viral escape mutant contained substitutions on the N-heptad repeat (NHR) segment of GP2, the fusion subunit. Truncation studies indicated that the size of the Fc impacts virus neutralization potential. Finally, we examined the protective efficacy of Fc-null mutants in mice, and found that Fc function was not required for high levels of protection. Altogether, these results indicate that neutralization of SUDV GP-mediated cell entry likely involves blockade of viral membrane fusion within endosomes, and that inhibition of viral entry is the likely mechanism of in vivo protection.
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Affiliation(s)
- Daniel Hofmann
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY 10461, USA
| | - Samantha E Zak
- Virology Division, United States Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, MD 21702, USA
| | - Elisabeth K Nyakatura
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY 10461, USA
| | - Eva Mittler
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY 10461, USA
| | - Russell R Bakken
- Virology Division, United States Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, MD 21702, USA
| | - Kartik Chandran
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY 10461, USA
| | - John M Dye
- Virology Division, United States Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, MD 21702, USA
| | - Jonathan R Lai
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY 10461, USA.
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47
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Antibodies from a Human Survivor Define Sites of Vulnerability for Broad Protection against Ebolaviruses. Cell 2017; 169:878-890.e15. [PMID: 28525755 DOI: 10.1016/j.cell.2017.04.037] [Citation(s) in RCA: 125] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/16/2017] [Accepted: 04/26/2017] [Indexed: 12/19/2022]
Abstract
Experimental monoclonal antibody (mAb) therapies have shown promise for treatment of lethal Ebola virus (EBOV) infections, but their species-specific recognition of the viral glycoprotein (GP) has limited their use against other divergent ebolaviruses associated with human disease. Here, we mined the human immune response to natural EBOV infection and identified mAbs with exceptionally potent pan-ebolavirus neutralizing activity and protective efficacy against three virulent ebolaviruses. These mAbs recognize an inter-protomer epitope in the GP fusion loop, a critical and conserved element of the viral membrane fusion machinery, and neutralize viral entry by targeting a proteolytically primed, fusion-competent GP intermediate (GPCL) generated in host cell endosomes. Only a few somatic hypermutations are required for broad antiviral activity, and germline-approximating variants display enhanced GPCL recognition, suggesting that such antibodies could be elicited more efficiently with suitably optimized GP immunogens. Our findings inform the development of both broadly effective immunotherapeutics and vaccines against filoviruses.
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48
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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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49
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Zhao X, Howell KA, He S, Brannan JM, Wec AZ, Davidson E, Turner HL, Chiang CI, Lei L, Fels JM, Vu H, Shulenin S, Turonis AN, Kuehne AI, Liu G, Ta M, Wang Y, Sundling C, Xiao Y, Spence JS, Doranz BJ, Holtsberg FW, Ward AB, Chandran K, Dye JM, Qiu X, Li Y, Aman MJ. Immunization-Elicited Broadly Protective Antibody Reveals Ebolavirus Fusion Loop as a Site of Vulnerability. Cell 2017; 169:891-904.e15. [PMID: 28525756 PMCID: PMC5803079 DOI: 10.1016/j.cell.2017.04.038] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/20/2017] [Accepted: 04/27/2017] [Indexed: 12/30/2022]
Abstract
While neutralizing antibodies are highly effective against ebolavirus infections, current experimental ebolavirus vaccines primarily elicit species-specific antibody responses. Here, we describe an immunization-elicited macaque antibody (CA45) that clamps the internal fusion loop with the N terminus of the ebolavirus glycoproteins (GPs) and potently neutralizes Ebola, Sudan, Bundibugyo, and Reston viruses. CA45, alone or in combination with an antibody that blocks receptor binding, provided full protection against all pathogenic ebolaviruses in mice, guinea pigs, and ferrets. Analysis of memory B cells from the immunized macaque suggests that elicitation of broadly neutralizing antibodies (bNAbs) for ebolaviruses is possible but difficult, potentially due to the rarity of bNAb clones and their precursors. Unexpectedly, germline-reverted CA45, while exhibiting negligible binding to full-length GP, bound a proteolytically remodeled GP with picomolar affinity, suggesting that engineered ebolavirus vaccines could trigger rare bNAb precursors more robustly. These findings have important implications for developing pan-ebolavirus vaccine and immunotherapeutic cocktails.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antibodies, Neutralizing/chemistry
- Antibodies, Neutralizing/immunology
- Antibodies, Neutralizing/isolation & purification
- Antibodies, Viral/chemistry
- Antibodies, Viral/immunology
- Antibodies, Viral/isolation & purification
- Complementarity Determining Regions
- Cross Reactions
- Ebola Vaccines/immunology
- Ebolavirus/immunology
- Epitope Mapping
- Epitopes, B-Lymphocyte/immunology
- Female
- Ferrets
- Guinea Pigs
- Hemorrhagic Fever, Ebola/immunology
- Immunoglobulin Fab Fragments/ultrastructure
- Macaca fascicularis
- Male
- Mice
- Mice, Inbred BALB C
- Models, Molecular
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Affiliation(s)
- Xuelian Zhao
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20878, USA
| | | | - Shihua He
- Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB R3E 3R2, Canada; Deparment of Medical Microbiology, University of Manitoba, MB R3E 0J9, Canada
| | - Jennifer M Brannan
- US Army Medical Research Institute of Infectious Diseases, Frederick, MD 21701, USA
| | - Anna Z Wec
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | | | - Hannah L Turner
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Chi-I Chiang
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20878, USA
| | - Lin Lei
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20878, USA
| | - J Maximilian Fels
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Hong Vu
- Integrated BioTherapeutics, Rockville, MD 20850, USA
| | | | | | - Ana I Kuehne
- US Army Medical Research Institute of Infectious Diseases, Frederick, MD 21701, USA
| | - Guodong Liu
- Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB R3E 3R2, Canada; Deparment of Medical Microbiology, University of Manitoba, MB R3E 0J9, Canada
| | - Mi Ta
- Integral Molecular, Philadelphia, PA 19104, USA
| | - Yimeng Wang
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20878, USA
| | - Christopher Sundling
- Immunology Division, Garvan Institute of Medical Research, Darlinghurst, New South Wales 2010, Australia
| | - Yongli Xiao
- Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Jennifer S Spence
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | | | | | - Andrew B Ward
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Kartik Chandran
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - John M Dye
- US Army Medical Research Institute of Infectious Diseases, Frederick, MD 21701, USA
| | - Xiangguo Qiu
- Special Pathogens Program, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB R3E 3R2, Canada; Deparment of Medical Microbiology, University of Manitoba, MB R3E 0J9, Canada
| | - Yuxing Li
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20878, USA; Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | - M Javad Aman
- Integrated BioTherapeutics, Rockville, MD 20850, USA.
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50
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Nelson EA, Dyall J, Hoenen T, Barnes AB, Zhou H, Liang JY, Michelotti J, Dewey WH, DeWald LE, Bennett RS, Morris PJ, Guha R, Klumpp-Thomas C, McKnight C, Chen YC, Xu X, Wang A, Hughes E, Martin S, Thomas C, Jahrling PB, Hensley LE, Olinger GG, White JM. The phosphatidylinositol-3-phosphate 5-kinase inhibitor apilimod blocks filoviral entry and infection. PLoS Negl Trop Dis 2017; 11:e0005540. [PMID: 28403145 PMCID: PMC5402990 DOI: 10.1371/journal.pntd.0005540] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 04/24/2017] [Accepted: 03/30/2017] [Indexed: 12/12/2022] Open
Abstract
Phosphatidylinositol-3-phosphate 5-kinase (PIKfyve) is a lipid kinase involved in endosome maturation that emerged from a haploid genetic screen as being required for Ebola virus (EBOV) infection. Here we analyzed the effects of apilimod, a PIKfyve inhibitor that was reported to be well tolerated in humans in phase 2 clinical trials, for its effects on entry and infection of EBOV and Marburg virus (MARV). We first found that apilimod blocks infections by EBOV and MARV in Huh 7, Vero E6 and primary human macrophage cells, with notable potency in the macrophages (IC50, 10 nM). We next observed that similar doses of apilimod block EBOV-glycoprotein-virus like particle (VLP) entry and transcription-replication competent VLP infection, suggesting that the primary mode of action of apilimod is as an entry inhibitor, preventing release of the viral genome into the cytoplasm to initiate replication. After providing evidence that the anti-EBOV action of apilimod is via PIKfyve, we showed that it blocks trafficking of EBOV VLPs to endolysosomes containing Niemann-Pick C1 (NPC1), the intracellular receptor for EBOV. Concurrently apilimod caused VLPs to accumulate in early endosome antigen 1-positive endosomes. We did not detect any effects of apilimod on bulk endosome acidification, on the activity of cathepsins B and L, or on cholesterol export from endolysosomes. Hence by antagonizing PIKfyve, apilimod appears to block EBOV trafficking to its site of fusion and entry into the cytoplasm. Given the drug's observed anti-filoviral activity, relatively unexplored mechanism of entry inhibition, and reported tolerability in humans, we propose that apilimod be further explored as part of a therapeutic regimen to treat filoviral infections.
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Affiliation(s)
- Elizabeth A. Nelson
- Department of Cell Biology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Julie Dyall
- Integrated Research Facility, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, Maryland, United States of America
| | - Thomas Hoenen
- Laboratory of Virology, Division of Intramural Research, National Institutes of Health, Hamilton, Montana, United States of America
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald–Insel Riems, Germany
| | - Alyson B. Barnes
- Department of Cell Biology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Huanying Zhou
- Integrated Research Facility, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, Maryland, United States of America
| | - Janie Y. Liang
- Integrated Research Facility, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, Maryland, United States of America
| | - Julia Michelotti
- Integrated Research Facility, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, Maryland, United States of America
| | - William H. Dewey
- Integrated Research Facility, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, Maryland, United States of America
| | - Lisa Evans DeWald
- Integrated Research Facility, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, Maryland, United States of America
| | - Richard S. Bennett
- Integrated Research Facility, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, Maryland, United States of America
| | - Patrick J. Morris
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Rajarshi Guha
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Carleen Klumpp-Thomas
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Crystal McKnight
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Yu-Chi Chen
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Xin Xu
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Amy Wang
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Emma Hughes
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Scott Martin
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Craig Thomas
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Peter B. Jahrling
- Integrated Research Facility, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, Maryland, United States of America
- Emerging Viral Pathogens Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, Maryland, United States of America
| | - Lisa E. Hensley
- Integrated Research Facility, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, Maryland, United States of America
| | - Gene G. Olinger
- Integrated Research Facility, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, Maryland, United States of America
| | - Judith M. White
- Department of Cell Biology, University of Virginia, Charlottesville, Virginia, United States of America
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