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Avanzato VA, Bushmaker T, Oguntuyo KY, Yinda CK, Duyvesteyn HME, Stass R, Meade-White K, Rosenke R, Thomas T, van Doremalen N, Saturday G, Doores KJ, Lee B, Bowden TA, Munster VJ. A monoclonal antibody targeting the Nipah virus fusion glycoprotein apex imparts protection from disease. J Virol 2024:e0063824. [PMID: 39240113 DOI: 10.1128/jvi.00638-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Accepted: 07/05/2024] [Indexed: 09/07/2024] Open
Abstract
Nipah virus (NiV) is a highly pathogenic paramyxovirus capable of causing severe respiratory and neurologic disease in humans. Currently, there are no licensed vaccines or therapeutics against NiV, underscoring the urgent need for the development of countermeasures. The NiV surface-displayed glycoproteins, NiV-G and NiV-F, mediate host cell attachment and fusion, respectively, and are heavily targeted by host antibodies. Here, we describe a vaccination-derived neutralizing monoclonal antibody, mAb92, that targets NiV-F. Structural characterization of the Fab region bound to NiV-F (NiV-F-Fab92) by cryo-electron microscopy analysis reveals an epitope in the DIII domain at the membrane distal apex of NiV-F, an established site of vulnerability on the NiV surface. Further, prophylactic treatment of hamsters with mAb92 offered complete protection from NiV disease, demonstrating beneficial activity of mAb92 in vivo. This work provides support for targeting NiV-F in the development of vaccines and therapeutics against NiV.IMPORTANCENipah virus (NiV) is a highly lethal henipavirus (HNV) that causes severe respiratory and neurologic disease in humans. Currently, there are no licensed vaccines or therapeutics against NiV, highlighting a need to develop countermeasures. The NiV surface displays the receptor binding protein (NiV-G, or RBP) and the fusion protein (NiV-F), which allow the virus to attach and enter cells. These proteins can be targeted by vaccines and antibodies to prevent disease. This work describes a neutralizing antibody (mAb92) that targets NiV-F. Structural characterization by cryo-electron microscopy analysis reveals where the antibody binds to NiV-F to neutralize the virus. This study also shows that prophylactic treatment of hamsters with mAb92 completely protected against developing NiV disease. This work shows how targeting NiV-F can be useful to preventing NiV disease, supporting future studies in the development of vaccines and therapeutics.
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Affiliation(s)
- Victoria A Avanzato
- Laboratory of Virology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Trenton Bushmaker
- Laboratory of Virology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Kasopefoluwa Y Oguntuyo
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Claude Kwe Yinda
- Laboratory of Virology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Helen M E Duyvesteyn
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Robert Stass
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Kimberly Meade-White
- Laboratory of Virology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Rebecca Rosenke
- Rocky Mountain Veterinary Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Tina Thomas
- Rocky Mountain Veterinary Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Neeltje van Doremalen
- Laboratory of Virology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Greg Saturday
- Rocky Mountain Veterinary Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
| | - Katie J Doores
- Department of Infectious Diseases, King's College London, Guy's Hospital, London, United Kingdom
| | - Benhur Lee
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Thomas A Bowden
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Vincent J Munster
- Laboratory of Virology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA
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2
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Sari IP, Ortiz CLD, Yang LW, Chen MH, Perng MD, Wu TY. Development of Fusion-Based Assay as a Drug Screening Platform for Nipah Virus Utilizing Baculovirus Expression Vector System. Int J Mol Sci 2024; 25:9102. [PMID: 39201788 PMCID: PMC11354753 DOI: 10.3390/ijms25169102] [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: 06/06/2024] [Revised: 08/15/2024] [Accepted: 08/20/2024] [Indexed: 09/03/2024] Open
Abstract
Nipah virus (NiV) is known to be a highly pathogenic zoonotic virus, which is included in the World Health Organization Research & Development Blueprint list of priority diseases with up to 70% mortality rate. Due to its high pathogenicity and outbreak potency, a therapeutic countermeasure against NiV is urgently needed. As NiV needs to be handled within a Biological Safety Level (BSL) 4 facility, we had developed a safe drug screening platform utilizing a baculovirus expression vector system (BEVS) based on a NiV-induced syncytium formation that could be handled within a BSL-1 facility. To reconstruct the NiV-induced syncytium formation in BEVS, two baculoviruses were generated to express recombinant proteins that are responsible for inducing the syncytium formation, including one baculovirus exhibiting co-expressed NiV fusion protein (NiV-F) and NiV attachment glycoprotein (NiV-G) and another exhibiting human EphrinB2 protein. Interestingly, syncytium formation was observed in infected insect cells when the medium was modified to have a lower pH level and supplemented with cholesterol. Fusion inhibitory properties of several compounds, such as phytochemicals and a polysulfonated naphthylamine compound, were evaluated using this platform. Among these compounds, suramin showed the highest fusion inhibitory activity against NiV-induced syncytium in the baculovirus expression system. Moreover, our in silico results provide a molecular-level glimpse of suramin's interaction with NiV-G's central hole and EphrinB2's G-H loop, which could be the possible reason for its fusion inhibitory activity.
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Affiliation(s)
- Indah Permata Sari
- Institute of Molecular Medicine, College of Life Science, National Tsing Hua University, Hsinchu 30013, Taiwan; (I.P.S.); (M.-H.C.)
- Department of Bioscience Technology, Chung Yuan Christian University, Chung-Li, Taoyuan City 320314, Taiwan
| | - Christopher Llynard D. Ortiz
- Chemical Biology and Molecular Biophysics Program, Taiwan International Graduate Program, Institute of Biological Chemistry, Academia Sinica, 128 Academia Road, Section 2, Taipei 11529, Taiwan; (C.L.D.O.); (L.-W.Y.)
- Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu 30013, Taiwan
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Lee-Wei Yang
- Chemical Biology and Molecular Biophysics Program, Taiwan International Graduate Program, Institute of Biological Chemistry, Academia Sinica, 128 Academia Road, Section 2, Taipei 11529, Taiwan; (C.L.D.O.); (L.-W.Y.)
- Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Ming-Hsiang Chen
- Institute of Molecular Medicine, College of Life Science, National Tsing Hua University, Hsinchu 30013, Taiwan; (I.P.S.); (M.-H.C.)
| | - Ming-Der Perng
- Institute of Molecular Medicine, College of Life Science, National Tsing Hua University, Hsinchu 30013, Taiwan; (I.P.S.); (M.-H.C.)
| | - Tzong-Yuan Wu
- Department of Bioscience Technology, Chung Yuan Christian University, Chung-Li, Taoyuan City 320314, Taiwan
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3
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Lubinski B, Whittaker GR. Host Cell Proteases Involved in Human Respiratory Viral Infections and Their Inhibitors: A Review. Viruses 2024; 16:984. [PMID: 38932275 PMCID: PMC11209347 DOI: 10.3390/v16060984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Revised: 06/06/2024] [Accepted: 06/11/2024] [Indexed: 06/28/2024] Open
Abstract
Viral tropism is most commonly linked to receptor use, but host cell protease use can be a notable factor in susceptibility to infection. Here we review the use of host cell proteases by human viruses, focusing on those with primarily respiratory tropism, particularly SARS-CoV-2. We first describe the various classes of proteases present in the respiratory tract, as well as elsewhere in the body, and incorporate the targeting of these proteases as therapeutic drugs for use in humans. Host cell proteases are also linked to the systemic spread of viruses and play important roles outside of the respiratory tract; therefore, we address how proteases affect viruses across the spectrum of infections that can occur in humans, intending to understand the extrapulmonary spread of SARS-CoV-2.
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Affiliation(s)
- Bailey Lubinski
- Department of Microbiology & Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14850, USA;
| | - Gary R. Whittaker
- Department of Microbiology & Immunology and Public & Ecosystem Health, College of Veterinary Medicine, Cornell University, Ithaca, NY 14850, USA
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4
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An D, Li Z, Beavis AC, Briggs KR, Harvill M, He B. Cleavage of the syncytial protein of J paramyxovirus is required for its ability to promote cell-cell fusion. Proc Natl Acad Sci U S A 2024; 121:e2403389121. [PMID: 38833471 PMCID: PMC11181024 DOI: 10.1073/pnas.2403389121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Accepted: 05/02/2024] [Indexed: 06/06/2024] Open
Abstract
Cell-cell fusion mediated by most paramyxovirus requires fusion protein (F) and attachment protein (H, HN, or G). The F protein is proteolytic cleaved to be fusogenically active. J paramyxovirus (JPV) has a unique feature in the family Paramyxoviridae: It encodes an integral membrane protein, syncytial protein (SP, formerly known as transmembrane protein, TM), which is essential in JPV-promoted cell-cell fusion (i.e., syncytial). In this study, we report that cleavage of SP is essential for its syncytial-promoting activity. We have identified the cleavage site of SP at amino acid residues 172 to 175, LKTG, and deletion of the "LKTG" residues abolished SP protein cleavage and its ability to promote cell-cell fusion. Replacing the cleavage site LKTG with a factor Xa protease cleavage site allows cleavage of the SP with factor Xa protease and restores its ability to promote cell-cell fusion. Furthermore, results from a hemifusion assay indicate that cleavage of SP plays an important role in the progression from the intermediate hemifusion state to a complete fusion. This work indicates that SP has many characteristics of a fusion protein. We propose that SP is likely a cell-cell fusion-promoting protein.
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Affiliation(s)
- Dong An
- Department of Infectious Diseases, University of Georgia College of Veterinary Medicine, Athens, GA30602
| | - Zhuo Li
- Department of Infectious Diseases, University of Georgia College of Veterinary Medicine, Athens, GA30602
| | - Ashley C. Beavis
- Department of Infectious Diseases, University of Georgia College of Veterinary Medicine, Athens, GA30602
| | - Kelsey R. Briggs
- Department of Infectious Diseases, University of Georgia College of Veterinary Medicine, Athens, GA30602
| | - Mason Harvill
- Department of Infectious Diseases, University of Georgia College of Veterinary Medicine, Athens, GA30602
| | - Biao He
- Department of Infectious Diseases, University of Georgia College of Veterinary Medicine, Athens, GA30602
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5
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Falke S, Lieske J, Herrmann A, Loboda J, Karničar K, Günther S, Reinke PYA, Ewert W, Usenik A, Lindič N, Sekirnik A, Dretnik K, Tsuge H, Turk V, Chapman HN, Hinrichs W, Ebert G, Turk D, Meents A. Structural Elucidation and Antiviral Activity of Covalent Cathepsin L Inhibitors. J Med Chem 2024; 67:7048-7067. [PMID: 38630165 PMCID: PMC11089505 DOI: 10.1021/acs.jmedchem.3c02351] [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: 12/15/2023] [Revised: 03/22/2024] [Accepted: 03/28/2024] [Indexed: 05/15/2024]
Abstract
Emerging RNA viruses, including SARS-CoV-2, continue to be a major threat. Cell entry of SARS-CoV-2 particles via the endosomal pathway involves cysteine cathepsins. Due to ubiquitous expression, cathepsin L (CatL) is considered a promising drug target in the context of different viral and lysosome-related diseases. We characterized the anti-SARS-CoV-2 activity of a set of carbonyl- and succinyl epoxide-based inhibitors, which were previously identified as inhibitors of cathepsins or related cysteine proteases. Calpain inhibitor XII, MG-101, and CatL inhibitor IV possess antiviral activity in the very low nanomolar EC50 range in Vero E6 cells and inhibit CatL in the picomolar Ki range. We show a relevant off-target effect of CatL inhibition by the coronavirus main protease α-ketoamide inhibitor 13b. Crystal structures of CatL in complex with 14 compounds at resolutions better than 2 Å present a solid basis for structure-guided understanding and optimization of CatL inhibitors toward protease drug development.
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Affiliation(s)
- Sven Falke
- Center
for Free-Electron Laser Science CFEL, Deutsches
Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Julia Lieske
- Center
for Free-Electron Laser Science CFEL, Deutsches
Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Alexander Herrmann
- Institute
of Virology, Helmholtz Munich, Ingolstädter Landstraße 1, 85764 Neuherberg, Munich, Germany
| | - Jure Loboda
- Department
of Biochemistry and Molecular and Structural Biology, Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
| | - Katarina Karničar
- Department
of Biochemistry and Molecular and Structural Biology, Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
- Centre
of Excellence for Integrated Approaches in Chemistry and Biology of
Proteins, Jamova 39, 1000 Ljubljana, Slovenia
| | - Sebastian Günther
- Center
for Free-Electron Laser Science CFEL, Deutsches
Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Patrick Y. A. Reinke
- Center
for Free-Electron Laser Science CFEL, Deutsches
Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Wiebke Ewert
- Center
for Free-Electron Laser Science CFEL, Deutsches
Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Aleksandra Usenik
- Department
of Biochemistry and Molecular and Structural Biology, Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
- Centre
of Excellence for Integrated Approaches in Chemistry and Biology of
Proteins, Jamova 39, 1000 Ljubljana, Slovenia
| | - Nataša Lindič
- Department
of Biochemistry and Molecular and Structural Biology, Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
| | - Andreja Sekirnik
- Department
of Biochemistry and Molecular and Structural Biology, Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
| | - Klemen Dretnik
- Department
of Biochemistry and Molecular and Structural Biology, Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
- The
Jožef Stefan International Postgraduate School, Jamova cesta 39, 1000 Ljubljana, Slovenia
| | - Hideaki Tsuge
- Faculty of
Life Sciences, Kyoto Sangyo University, Kyoto 603-8555, Japan
| | - Vito Turk
- Department
of Biochemistry and Molecular and Structural Biology, Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
| | - Henry N. Chapman
- Center
for Free-Electron Laser Science CFEL, Deutsches
Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
- Hamburg
Centre for Ultrafast Imaging, Universität
Hamburg, Luruper Chaussee
149, 22761 Hamburg, Germany
- Department
of Physics, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Winfried Hinrichs
- Institute
of Biochemistry, Universität Greifswald, Felix-Hausdorff-Str. 4, 17489 Greifswald, Germany
| | - Gregor Ebert
- Institute
of Virology, Helmholtz Munich, Ingolstädter Landstraße 1, 85764 Neuherberg, Munich, Germany
- Institute
of Virology, Technical University of Munich, Trogerstraße 30, 81675 Munich, Germany
| | - Dušan Turk
- Department
of Biochemistry and Molecular and Structural Biology, Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
- Centre
of Excellence for Integrated Approaches in Chemistry and Biology of
Proteins, Jamova 39, 1000 Ljubljana, Slovenia
| | - Alke Meents
- Center
for Free-Electron Laser Science CFEL, Deutsches
Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
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6
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Zeitlin L, Cross RW, Woolsey C, West BR, Borisevich V, Agans KN, Prasad AN, Deer DJ, Stuart L, McCavitt-Malvido M, Kim DH, Pettitt J, Crowe JE, Whaley KJ, Veesler D, Dimitrov A, Abelson DM, Geisbert TW, Broder CC. Therapeutic administration of a cross-reactive mAb targeting the fusion glycoprotein of Nipah virus protects nonhuman primates. Sci Transl Med 2024; 16:eadl2055. [PMID: 38569014 DOI: 10.1126/scitranslmed.adl2055] [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: 10/05/2023] [Accepted: 03/03/2024] [Indexed: 04/05/2024]
Abstract
No licensed vaccines or therapies exist for patients infected with Nipah virus (NiV), although an experimental human monoclonal antibody (mAb) cross-reactive to the NiV and Hendra virus (HeV) G glycoprotein, m102.4, has been tested in a phase 1 trial and has been provided under compassionate use for both HeV and NiV exposures. NiV is a highly pathogenic zoonotic paramyxovirus causing regular outbreaks in humans and animals in South and Southeast Asia. The mortality rate of NiV infection in humans ranges from 40% to more than 90%, making it a substantial public health concern. The NiV G glycoprotein mediates host cell attachment, and the F glycoprotein facilitates membrane fusion and infection. We hypothesized that a mAb against the prefusion conformation of the F glycoprotein may confer better protection than m102.4. To test this, two potent neutralizing mAbs against NiV F protein, hu1F5 and hu12B2, were compared in a hamster model. Hu1F5 provided superior protection to hu12B2 and was selected for comparison with m102.4 for the ability to protect African green monkeys (AGMs) from a stringent NiV challenge. AGMs were exposed intranasally to the Bangladesh strain of NiV and treated 5 days after exposure with either mAb (25 milligrams per kilogram). Whereas only one of six AGMs treated with m102.4 survived until the study end point, all six AGMs treated with hu1F5 were protected. Furthermore, a reduced 10 milligrams per kilogram dose of hu1F5 also provided complete protection against NiV challenge, supporting the upcoming clinical advancement of this mAb for postexposure prophylaxis and therapy.
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Affiliation(s)
| | - Robert W Cross
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston National Laboratory, Galveston, TX 77550, USA
| | - Courtney Woolsey
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston National Laboratory, Galveston, TX 77550, USA
| | | | - Viktoriya Borisevich
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston National Laboratory, Galveston, TX 77550, USA
| | - Krystle N Agans
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston National Laboratory, Galveston, TX 77550, USA
| | - Abhishek N Prasad
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston National Laboratory, Galveston, TX 77550, USA
| | - Daniel J Deer
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston National Laboratory, Galveston, TX 77550, USA
| | | | | | - Do H Kim
- Mapp Biopharmaceutical, San Diego, CA 92121, USA
| | | | - James E Crowe
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | | | - David Veesler
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
- Howard Hughes Medical Institute, Seattle, WA 98195, USA
| | - Antony Dimitrov
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, MD 20814, USA
- Henry M. Jackson Foundation for the Advancement of Military Medicine Inc., Bethesda, MD 20814, USA
| | | | - Thomas W Geisbert
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston National Laboratory, Galveston, TX 77550, USA
| | - Christopher C Broder
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, MD 20814, USA
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7
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Diederich S, Babiuk S, Boshra H. A Survey of Henipavirus Tropism-Our Current Understanding from a Species/Organ and Cellular Level. Viruses 2023; 15:2048. [PMID: 37896825 PMCID: PMC10611353 DOI: 10.3390/v15102048] [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: 08/18/2023] [Revised: 09/22/2023] [Accepted: 09/29/2023] [Indexed: 10/29/2023] Open
Abstract
Henipaviruses are single-stranded RNA viruses that have been shown to be virulent in several species, including humans, pigs, horses, and rodents. Isolated nearly 30 years ago, these viruses have been shown to be of particular concern to public health, as at least two members (Nipah and Hendra viruses) are highly virulent, as well as zoonotic, and are thus classified as BSL4 pathogens. Although only 5 members of this genus have been isolated and characterized, metagenomics analysis using animal fluids and tissues has demonstrated the existence of other novel henipaviruses, suggesting a far greater degree of phylogenetic diversity than is currently known. Using a variety of molecular biology techniques, it has been shown that these viruses exhibit varying degrees of tropism on a species, organ/tissue, and cellular level. This review will attempt to provide a general overview of our current understanding of henipaviruses, with a particular emphasis on viral tropism.
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Affiliation(s)
- Sandra Diederich
- Institute of Novel and Emerging Infectious Diseases, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, 17493 Greifswald, Germany;
| | - Shawn Babiuk
- Canadian Food Inspection Agency, National Centre for Foreign Animal Disease, Winnipeg, MB R3E EM4, Canada;
| | - Hani Boshra
- Global Urgent and Advanced Research and Development (GUARD), 911 rue Principale, Batiscan, QC G0X 1A0, Canada
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8
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Isaacs A, Low YS, Macauslane KL, Seitanidou J, Pegg CL, Cheung STM, Liang B, Scott CAP, Landsberg MJ, Schulz BL, Chappell KJ, Modhiran N, Watterson D. Structure and antigenicity of divergent Henipavirus fusion glycoproteins. Nat Commun 2023; 14:3577. [PMID: 37328468 PMCID: PMC10275869 DOI: 10.1038/s41467-023-39278-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 06/02/2023] [Indexed: 06/18/2023] Open
Abstract
In August 2022, a novel henipavirus (HNV) named Langya virus (LayV) was isolated from patients with severe pneumonic disease in China. This virus is closely related to Mòjiāng virus (MojV), and both are divergent from the bat-borne HNV members, Nipah (NiV) and Hendra (HeV) viruses. The spillover of LayV is the first instance of a HNV zoonosis to humans outside of NiV and HeV, highlighting the continuing threat this genus poses to human health. In this work, we determine the prefusion structures of MojV and LayV F proteins via cryogenic electron microscopy to 2.66 and 3.37 Å, respectively. We show that despite sequence divergence from NiV, the F proteins adopt an overall similar structure but are antigenically distinct as they do not react to known antibodies or sera. Glycoproteomic analysis revealed that while LayV F is less glycosylated than NiV F, it contains a glycan that shields a site of vulnerability previously identified for NiV. These findings explain the distinct antigenic profile of LayV and MojV F, despite the extent to which they are otherwise structurally similar to NiV. Our results carry implications for broad-spectrum HNV vaccines and therapeutics, and indicate an antigenic, yet not structural, divergence from prototypical HNVs.
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Affiliation(s)
- Ariel Isaacs
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
| | - Yu Shang Low
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
| | - Kyle L Macauslane
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
| | - Joy Seitanidou
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
| | - Cassandra L Pegg
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
| | - Stacey T M Cheung
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
| | - Benjamin Liang
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
| | - Connor A P Scott
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
| | - Michael J Landsberg
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
- Australian Infectious Disease Research Centre, The University of Queensland, Brisbane, Australia
| | - Benjamin L Schulz
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
- Australian Infectious Disease Research Centre, The University of Queensland, Brisbane, Australia
| | - Keith J Chappell
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
- Australian Infectious Disease Research Centre, The University of Queensland, Brisbane, Australia
- Australian Institute for Bioengineering and Nanotechnology, Brisbane, Australia
| | - Naphak Modhiran
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia.
| | - Daniel Watterson
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia.
- Australian Infectious Disease Research Centre, The University of Queensland, Brisbane, Australia.
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9
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Pseudotyped Virus for Henipavirus. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1407:175-190. [PMID: 36920697 DOI: 10.1007/978-981-99-0113-5_9] [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
The genus Henipavirus (HNV) includes two virulent infectious viruses, Nipah virus (NiV) and Hendra virus (HeV), which are the focus of considerable public health research efforts and have been classified as priority infectious diseases by the World Health Organization. Both viruses are high risk and should be handled in biosafety level 4 laboratories. Pseudotyped viruses containing the envelope proteins of HNV viruses have the same envelope protein structure as the authentic viruses; thus, they can mimic the receptor-binding and membrane fusion processes of authentic viruses with host cells and can be handled in biosafety level 2 laboratories. These characteristics enable pseudotyped viruses to be widely used in studies of viral infection mechanisms (packaging, budding, virus attachment, membrane fusion, viral entry, and glycosylation), inhibitory drug screening assays, and monoclonal antibody neutralization characteristics. This review will provide an overview of the progress of research concerning pseudotyped virus packaging systems for NiV and HeV.
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10
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FeMV is a cathepsin-dependent unique morbillivirus infecting the kidneys of domestic cats. Proc Natl Acad Sci U S A 2022; 119:e2209405119. [PMID: 36251995 PMCID: PMC9618091 DOI: 10.1073/pnas.2209405119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Feline morbillivirus (FeMV) is a recently discovered pathogen of domestic cats and has been classified as a morbillivirus in the Paramyxovirus family. We determined the complete sequence of FeMVUS5 directly from an FeMV-positive urine sample without virus isolation or cell passage. Sequence analysis of the viral genome revealed potential divergence from characteristics of archetypal morbilliviruses. First, the virus lacks the canonical polybasic furin cleavage signal in the fusion (F) glycoprotein. Second, conserved amino acids in the hemagglutinin (H) glycoprotein used by all other morbilliviruses for binding and/or fusion activation with the cellular receptor CD150 (signaling lymphocyte activation molecule [SLAM]/F1) are absent. We show that, despite this sequence divergence, FeMV H glycoprotein uses feline CD150 as a receptor and cannot use human CD150. We demonstrate that the protease responsible for cleaving the FeMV F glycoprotein is a cathepsin, making FeMV a unique morbillivirus and more similar to the closely related zoonotic Nipah and Hendra viruses. We developed a reverse genetics system for FeMVUS5 and generated recombinant viruses expressing Venus fluorescent protein from an additional transcription unit located either between the phospho-protein (P) and matrix (M) genes or the H and large (L) genes of the genome. We used these recombinant FeMVs to establish a natural infection and demonstrate that FeMV causes an acute morbillivirus-like disease in the cat. Virus was shed in the urine and detectable in the kidneys at later time points. This opens the door for long-term studies to address the postulated role of this morbillivirus in the development of chronic kidney disease.
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11
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Günther SC, Martínez-Romero C, Sempere Borau M, Pham CTN, García-Sastre A, Stertz S. Proteomic Identification of Potential Target Proteins of Cathepsin W for Its Development as a Drug Target for Influenza. Microbiol Spectr 2022; 10:e0092122. [PMID: 35867415 PMCID: PMC9431242 DOI: 10.1128/spectrum.00921-22] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 07/01/2022] [Indexed: 11/24/2022] Open
Abstract
Influenza A virus (IAV) coopts numerous host factors for efficient replication. The cysteine protease cathepsin W (CTSW) has been identified as one host factor required for IAV entry, specifically for the escape of IAVs from late endosomes. However, the substrate specificity of CTSW and the proviral mechanism are thus far unknown. Here, we show that intracellular but not secreted CTSW promotes viral entry. We reveal 79 potential direct and 31 potential indirect cellular target proteins of CTSW using the high-throughput proteomic approach terminal amine isotopic labeling of substrates (TAILS) and determine the cleavage motif shared by the substrates of CTSW. Subsequent integration with data from RNA interference (RNAi) screens for IAV host factors uncovers first insights into the proviral function of CTSW. Notably, CTSW-deficient mice display a 25% increase in survival and a delay in mortality compared to wild-type mice upon IAV infection. Altogether, these findings support the development of drugs targeting CTSW as novel host-directed antiviral therapies. IMPORTANCE Influenza viruses are respiratory pathogens and pose a constant threat to human health. Although antiviral drugs are available for influenza, the emergence and spread of drug-resistant viruses is cause for concern. Therefore, the development of new antivirals with lower chances of their target viruses acquiring resistance is urgently needed to reduce the high morbidity and mortality caused by influenza. Promising alternatives to drugs targeting viral proteins are those directed against host factors required for viral replication. The cysteine protease cathepsin W (CTSW) is an important host factor for IAV replication, and its proteolytic activity is required for fusion of viral and endosomal membranes. In this work, we identify a number of hitherto unknown CTSW substrates, providing new insights into virus-host interactions, and reveal that CTSW might also play a proviral role in an in vivo model. These results support the development of CTSW as a drug target for next-generation antivirals against influenza.
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Affiliation(s)
- Sira C. Günther
- Institute of Medical Virology, University of Zurich, Zurich, Switzerland
- Life Science Zurich Graduate School, ETH and University of Zurich, Zurich, Switzerland
| | - Carles Martínez-Romero
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Milagros Sempere Borau
- Institute of Medical Virology, University of Zurich, Zurich, Switzerland
- Life Science Zurich Graduate School, ETH and University of Zurich, Zurich, Switzerland
| | - Christine T. N. Pham
- Department of Medicine, Division of Rheumatology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Adolfo García-Sastre
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- The Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Department of Pathology, Molecular and Cell-Based Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Silke Stertz
- Institute of Medical Virology, University of Zurich, Zurich, Switzerland
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12
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Wang Z, Dang HV, Amaya M, Xu Y, Yin R, Yan L, Hickey AC, Annand EJ, Horsburgh BA, Reid PA, Smith I, Eden JS, Xu K, Broder CC, Veesler D. Potent monoclonal antibody-mediated neutralization of a divergent Hendra virus variant. Proc Natl Acad Sci U S A 2022; 119:e2122769119. [PMID: 35617431 PMCID: PMC9295758 DOI: 10.1073/pnas.2122769119] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 04/16/2022] [Indexed: 12/27/2022] Open
Abstract
Hendra virus (HeV) and Nipah virus (NiV) are deadly zoonotic Henipaviruses (HNVs) responsible for recurrent outbreaks in humans and domestic species of highly fatal (50 to 95%) disease. A HeV variant (HeV-g2) of unprecedented genetic divergence has been identified in two fatally diseased horses, and in two flying fox species in regions of Australia not previously considered at risk for HeV spillover. Given the HeV-g2 divergence from HeV while retaining equivalent pathogenicity and spillover potential, understanding receptor usage and antigenic properties is urgently required to guide One Health biosecurity. Here, we show that the HeV-g2 G glycoprotein shares a conserved receptor tropism with prototypic HeV and that a panel of monoclonal antibodies recognizing the G and F glycoproteins potently neutralizes HeV-g2– and HeV G/F–mediated entry into cells. We determined a crystal structure of the Fab fragment of the hAH1.3 antibody bound to the HeV G head domain, revealing an antigenic site associated with potent cross-neutralization of both HeV-g2 and HeV. Structure-guided formulation of a tetravalent monoclonal antibody (mAb) mixture, targeting four distinct G head antigenic sites, results in potent neutralization of HeV and HeV-g2 and delineates a path forward for implementing multivalent mAb combinations for postexposure treatment of HNV infections.
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Affiliation(s)
- Zhaoqian Wang
- Department of Biochemistry, University of Washington, Seattle, WA 98195
| | - Ha V. Dang
- Department of Biochemistry, University of Washington, Seattle, WA 98195
| | - Moushimi Amaya
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, MD 20814
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD 20814
| | - Yan Xu
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210
| | - Randy Yin
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, MD 20814
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD 20814
| | - Lianying Yan
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, MD 20814
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD 20814
| | - Andrew C. Hickey
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD 20814
- US Public Health Services Commissioned Corps, Rockville, MD 20852
| | - Edward J. Annand
- Sydney School of Veterinary Science, University of Sydney, Sydney, 2570 NSW, Australia
- Sydney Institute for Infectious Diseases, University of Sydney, Sydney, 2006 NSW, Australia
- Black Mountain Laboratories, Health and Biosecurity, Commonwealth Scientific and Industrial Research Organisation, Canberra, 2601 ACT, Australia
- Equine Veterinary and One Health Epidemiology, EquiEpiVet, Aireys Inlet, Surf Coast, 3231 VIC, Australia
| | - Bethany A. Horsburgh
- University of Sydney School of Medicine, Sydney, 2006 NSW, Australia
- Westmead Institute for Medical Research, Sydney, 2145 NSW, Australia
| | - Peter A. Reid
- Private Equine Veterinary Practice, Brisbane, 4034 QLD, Australia
| | - Ina Smith
- Black Mountain Laboratories, Health and Biosecurity, Commonwealth Scientific and Industrial Research Organisation, Canberra, 2601 ACT, Australia
| | - John-Sebastian Eden
- University of Sydney School of Medicine, Sydney, 2006 NSW, Australia
- Westmead Institute for Medical Research, Sydney, 2145 NSW, Australia
| | - Kai Xu
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210
| | - Christopher C. Broder
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, MD 20814
| | - David Veesler
- Department of Biochemistry, University of Washington, Seattle, WA 98195
- HHMI, University of Washington, Seattle, WA 98195
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13
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Kovač V, Čurin Šerbec V. Prion Protein: The Molecule of Many Forms and Faces. Int J Mol Sci 2022; 23:ijms23031232. [PMID: 35163156 PMCID: PMC8835406 DOI: 10.3390/ijms23031232] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 01/10/2022] [Accepted: 01/21/2022] [Indexed: 02/06/2023] Open
Abstract
Cellular prion protein (PrPC) is a glycosylphosphatidylinositol (GPI)-anchored protein most abundantly found in the outer membrane of neurons. Due to structural characteristics (a flexible tail and structured core), PrPC interacts with a wide range of partners. Although PrPC has been proposed to be involved in many physiological functions, only peripheral nerve myelination homeostasis has been confirmed as a bona fide function thus far. PrPC misfolding causes prion diseases and PrPC has been shown to mediate β-rich oligomer-induced neurotoxicity in Alzheimer’s and Parkinson’s disease as well as neuroprotection in ischemia. Upon proteolytic cleavage, PrPC is transformed into released and attached forms of PrP that can, depending on the contained structural characteristics of PrPC, display protective or toxic properties. In this review, we will outline prion protein and prion protein fragment properties as well as overview their involvement with interacting partners and signal pathways in myelination, neuroprotection and neurodegenerative diseases.
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14
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White JM, Schiffer JT, Bender Ignacio RA, Xu S, Kainov D, Ianevski A, Aittokallio T, Frieman M, Olinger GG, Polyak SJ. Drug Combinations as a First Line of Defense against Coronaviruses and Other Emerging Viruses. mBio 2021; 12:e0334721. [PMID: 34933447 PMCID: PMC8689562 DOI: 10.1128/mbio.03347-21] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The world was unprepared for coronavirus disease 2019 (COVID-19) and remains ill-equipped for future pandemics. While unprecedented strides have been made developing vaccines and treatments for COVID-19, there remains a need for highly effective and widely available regimens for ambulatory use for novel coronaviruses and other viral pathogens. We posit that a priority is to develop pan-family drug cocktails to enhance potency, limit toxicity, and avoid drug resistance. We urge cocktail development for all viruses with pandemic potential both in the short term (<1 to 2 years) and longer term with pairs of drugs in advanced clinical testing or repurposed agents approved for other indications. While significant efforts were launched against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), in vitro and in the clinic, many studies employed solo drugs and had disappointing results. Here, we review drug combination studies against SARS-CoV-2 and other viruses and introduce a model-driven approach to assess drug pairs with the highest likelihood of clinical efficacy. Where component agents lack sufficient potency, we advocate for synergistic combinations to achieve therapeutic levels. We also discuss issues that stymied therapeutic progress against COVID-19, including testing of agents with low likelihood of efficacy late in clinical disease and lack of focus on developing virologic surrogate endpoints. There is a need to expedite efficient clinical trials testing drug combinations that could be taken at home by recently infected individuals and exposed contacts as early as possible during the next pandemic, whether caused by a coronavirus or another viral pathogen. The approach herein represents a proactive plan for global viral pandemic preparedness.
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Affiliation(s)
- Judith M. White
- University of Virginia, Department of Cell Biology, Charlottesville, Virginia, USA
- University of Virginia, Department of Microbiology, Charlottesville, Virginia, USA
| | - Joshua T. Schiffer
- University of Washington, Division of Allergy and Infectious Diseases, Seattle, Washington, USA
- Fred Hutchinson Cancer Research Center, Vaccine and Infectious Diseases Division, Seattle, Washington, USA
| | - Rachel A. Bender Ignacio
- University of Washington, Division of Allergy and Infectious Diseases, Seattle, Washington, USA
- Fred Hutchinson Cancer Research Center, Vaccine and Infectious Diseases Division, Seattle, Washington, USA
| | - Shuang Xu
- Fred Hutchinson Cancer Research Center, Vaccine and Infectious Diseases Division, Seattle, Washington, USA
| | - Denis Kainov
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway
- Institute of Technology, University of Tartu, Tartu, Estonia
- Institute for Molecular Medicine Finland, FIMM, University of Helsinki, Helsinki, Finland
| | - Aleksandr Ianevski
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway
- Institute for Molecular Medicine Finland, FIMM, University of Helsinki, Helsinki, Finland
| | - Tero Aittokallio
- Institute for Molecular Medicine Finland, FIMM, University of Helsinki, Helsinki, Finland
- Oslo Centre for Biostatistics and Epidemiology (OCBE), University of Oslo, Oslo, Norway
- Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Matthew Frieman
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | | | - Stephen J. Polyak
- Virology Division, Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, USA
- Department of Global Health, University of Washington, Seattle, Washington, USA
- Department of Microbiology, University of Washington, Seattle, Washington, USA
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15
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Antivirals targeting paramyxovirus membrane fusion. Curr Opin Virol 2021; 51:34-47. [PMID: 34592709 DOI: 10.1016/j.coviro.2021.09.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 09/01/2021] [Accepted: 09/02/2021] [Indexed: 01/29/2023]
Abstract
The Paramyxoviridae family includes enveloped single-stranded negative-sense RNA viruses such as measles, mumps, human parainfluenza, canine distemper, Hendra, and Nipah viruses, which cause a tremendous global health burden. The ability of paramyxoviral glycoproteins to merge viral and host membranes allows entry of the viral genome into host cells, as well as cell-cell fusion, an important contributor to disease progression. Recent molecular and structural advances in our understanding of the paramyxovirus membrane fusion machinery gave rise to various therapeutic approaches aiming at inhibiting viral infection, spread, and cytopathic effects. These therapeutic approaches include peptide mimics, antibodies, and small molecule inhibitors with various levels of success at inhibiting viral entry, increasing the potential of effective antiviral therapeutic development.
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16
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Gamble A, Yeo YY, Butler AA, Tang H, Snedden CE, Mason CT, Buchholz DW, Bingham J, Aguilar HC, Lloyd-Smith JO. Drivers and Distribution of Henipavirus-Induced Syncytia: What Do We Know? Viruses 2021; 13:1755. [PMID: 34578336 PMCID: PMC8472861 DOI: 10.3390/v13091755] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/21/2021] [Accepted: 08/25/2021] [Indexed: 12/20/2022] Open
Abstract
Syncytium formation, i.e., cell-cell fusion resulting in the formation of multinucleated cells, is a hallmark of infection by paramyxoviruses and other pathogenic viruses. This natural mechanism has historically been a diagnostic marker for paramyxovirus infection in vivo and is now widely used for the study of virus-induced membrane fusion in vitro. However, the role of syncytium formation in within-host dissemination and pathogenicity of viruses remains poorly understood. The diversity of henipaviruses and their wide host range and tissue tropism make them particularly appropriate models with which to characterize the drivers of syncytium formation and the implications for virus fitness and pathogenicity. Based on the henipavirus literature, we summarized current knowledge on the mechanisms driving syncytium formation, mostly acquired from in vitro studies, and on the in vivo distribution of syncytia. While these data suggest that syncytium formation widely occurs across henipaviruses, hosts, and tissues, we identified important data gaps that undermined our understanding of the role of syncytium formation in virus pathogenesis. Based on these observations, we propose solutions of varying complexity to fill these data gaps, from better practices in data archiving and publication for in vivo studies, to experimental approaches in vitro.
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Affiliation(s)
- Amandine Gamble
- Department of Ecology & Evolutionary Biology, University of California Los Angeles, Los Angeles, CA 90095, USA; (A.A.B.); (H.T.); (C.E.S.); (J.O.L.-S.)
| | - Yao Yu Yeo
- Department of Microbiology & Immunology, Cornell University, Ithaca, NY 14850, USA; (Y.Y.Y.); (D.W.B.); (H.C.A.)
| | - Aubrey A. Butler
- Department of Ecology & Evolutionary Biology, University of California Los Angeles, Los Angeles, CA 90095, USA; (A.A.B.); (H.T.); (C.E.S.); (J.O.L.-S.)
| | - Hubert Tang
- Department of Ecology & Evolutionary Biology, University of California Los Angeles, Los Angeles, CA 90095, USA; (A.A.B.); (H.T.); (C.E.S.); (J.O.L.-S.)
| | - Celine E. Snedden
- Department of Ecology & Evolutionary Biology, University of California Los Angeles, Los Angeles, CA 90095, USA; (A.A.B.); (H.T.); (C.E.S.); (J.O.L.-S.)
| | - Christian T. Mason
- Department of Computational Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA;
| | - David W. Buchholz
- Department of Microbiology & Immunology, Cornell University, Ithaca, NY 14850, USA; (Y.Y.Y.); (D.W.B.); (H.C.A.)
| | - John Bingham
- CSIRO Australian Centre for Disease Preparedness, Geelong, VIC 3220, Australia;
| | - Hector C. Aguilar
- Department of Microbiology & Immunology, Cornell University, Ithaca, NY 14850, USA; (Y.Y.Y.); (D.W.B.); (H.C.A.)
| | - James O. Lloyd-Smith
- Department of Ecology & Evolutionary Biology, University of California Los Angeles, Los Angeles, CA 90095, USA; (A.A.B.); (H.T.); (C.E.S.); (J.O.L.-S.)
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17
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Dang HV, Cross RW, Borisevich V, Bornholdt ZA, West BR, Chan YP, Mire CE, Da Silva SC, Dimitrov AS, Yan L, Amaya M, Navaratnarajah CK, Zeitlin L, Geisbert TW, Broder CC, Veesler D. Broadly neutralizing antibody cocktails targeting Nipah virus and Hendra virus fusion glycoproteins. Nat Struct Mol Biol 2021; 28:426-434. [PMID: 33927387 DOI: 10.1038/s41594-021-00584-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 03/17/2021] [Indexed: 02/02/2023]
Abstract
Hendra virus (HeV) and Nipah virus (NiV) are henipaviruses (HNVs) causing respiratory illness and severe encephalitis in humans, with fatality rates of 50-100%. There are no licensed therapeutics or vaccines to protect humans. HeV and NiV use a receptor-binding glycoprotein (G) and a fusion glycoprotein (F) to enter host cells. HNV F and G are the main targets of the humoral immune response, and the presence of neutralizing antibodies is a correlate of protection against NiV and HeV in experimentally infected animals. We describe here two cross-reactive F-specific antibodies, 1F5 and 12B2, that neutralize NiV and HeV through inhibition of membrane fusion. Cryo-electron microscopy structures reveal that 1F5 and 12B2 recognize distinct prefusion-specific, conserved quaternary epitopes and lock F in its prefusion conformation. We provide proof-of-concept for using antibody cocktails for neutralizing NiV and HeV and define a roadmap for developing effective countermeasures against these highly pathogenic viruses.
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Affiliation(s)
- Ha V Dang
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Robert W Cross
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, USA.,Galveston National Laboratory, University of Texas Medical Branch, Galveston, TX, USA
| | - Viktoriya Borisevich
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, USA
| | | | | | - Yee-Peng Chan
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, MD, USA
| | - Chad E Mire
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, USA.,Galveston National Laboratory, University of Texas Medical Branch, Galveston, TX, USA
| | | | - Antony S Dimitrov
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, MD, USA
| | - Lianying Yan
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, MD, USA
| | - Moushimi Amaya
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, MD, USA
| | | | | | - Thomas W Geisbert
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, USA.,Galveston National Laboratory, University of Texas Medical Branch, Galveston, TX, USA
| | - Christopher C Broder
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, MD, USA
| | - David Veesler
- Department of Biochemistry, University of Washington, Seattle, WA, USA.
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18
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Novel Roles of the N1 Loop and N4 Alpha-Helical Region of the Nipah Virus Fusion Glycoprotein in Modulating Early and Late Steps of the Membrane Fusion Cascade. J Virol 2021; 95:JVI.01707-20. [PMID: 33568505 DOI: 10.1128/jvi.01707-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 01/27/2021] [Indexed: 11/20/2022] Open
Abstract
Nipah virus (NiV) is a zoonotic bat henipavirus in the family Paramyxoviridae NiV is deadly to humans, infecting host cells by direct fusion of the viral and host cell plasma membranes. This membrane fusion process is coordinated by the receptor-binding attachment (G) and fusion (F) glycoproteins. Upon G-receptor binding, F fuses membranes via a cascade that sequentially involves F-triggering, fusion pore formation, and viral or genome entry into cells. Using NiV as an important paramyxoviral model, we identified two novel regions in F that modulate the membrane fusion cascade. For paramyxoviruses and other viral families with class I fusion proteins, the heptad repeat 1 (HR1) and HR2 regions in the fusion protein prefusion conformation bind to form a six-helix bundle in the postfusion conformation. Here, structural comparisons between the F prefusion and postfusion conformations revealed that a short loop region (N1) undergoes dramatic spatial reorganization and a short alpha helix (N4) undergoes secondary structural changes. The roles of the N1 and N4 regions during the membrane fusion cascade, however, remain unknown for henipaviruses and paramyxoviruses. By performing alanine scanning mutagenesis and various functional analyses, we report that specific residues within these regions alter various steps in the membrane fusion cascade. While the N1 region affects early F-triggering, the N4 region affects F-triggering, F thermostability, and extensive fusion pore expansion during syncytium formation, also uncovering a link between F-G interactions and F-triggering. These novel mechanistic roles expand our understanding of henipaviral and paramyxoviral F-triggering, viral entry, and cell-cell fusion (syncytia), a pathognomonic feature of paramyxoviral infections.IMPORTANCE Henipaviruses infect bats, agriculturally important animals, and humans, with high mortality rates approaching ∼75% in humans. Known human outbreaks have been concentrated in Southeast Asia and Australia. Furthermore, about 20 new henipaviral species have been recently discovered in bats, with geographical spans in Asia, Africa, and South America. The development of antiviral therapeutics requires a thorough understanding of the mechanism of viral entry into host cells. In this study, we discovered novel roles of two regions within the fusion protein of the deadly henipavirus NiV. Such roles were in allowing viral entry into host cells and cell-cell fusion, a pathological hallmark of this and other paramyxoviruses. These novel roles were in the previously undescribed N1 and N4 regions within the fusion protein, modulating early and late steps of these important processes of viral infection and henipaviral disease. Notably, this knowledge may apply to other henipaviruses and more broadly to other paramyxoviruses.
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19
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Fosse JH, Haraldsen G, Falk K, Edelmann R. Endothelial Cells in Emerging Viral Infections. Front Cardiovasc Med 2021; 8:619690. [PMID: 33718448 PMCID: PMC7943456 DOI: 10.3389/fcvm.2021.619690] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 02/01/2021] [Indexed: 12/11/2022] Open
Abstract
There are several reasons to consider the role of endothelial cells in COVID-19 and other emerging viral infections. First, severe cases of COVID-19 show a common breakdown of central vascular functions. Second, SARS-CoV-2 replicates in endothelial cells. Third, prior deterioration of vascular function exacerbates disease, as the most common comorbidities of COVID-19 (obesity, hypertension, and diabetes) are all associated with endothelial dysfunction. Importantly, SARS-CoV-2's ability to infect endothelium is shared by many emerging viruses, including henipaviruses, hantavirus, and highly pathogenic avian influenza virus, all specifically targeting endothelial cells. The ability to infect endothelium appears to support generalised dissemination of infection and facilitate the access to certain tissues. The disturbed vascular function observed in severe COVID-19 is also a prominent feature of many other life-threatening viral diseases, underscoring the need to understand how viruses modulate endothelial function. We here review the role of vascular endothelial cells in emerging viral infections, starting with a summary of endothelial cells as key mediators and regulators of vascular and immune responses in health and infection. Next, we discuss endotheliotropism as a possible virulence factor and detail features that regulate viruses' ability to attach to and enter endothelial cells. We move on to review how endothelial cells detect invading viruses and respond to infection, with particular focus on pathways that may influence vascular function and the host immune system. Finally, we discuss how endothelial cell function can be dysregulated in viral disease, either by viral components or as bystander victims of overshooting or detrimental inflammatory and immune responses. Many aspects of how viruses interact with the endothelium remain poorly understood. Considering the diversity of such mechanisms among different emerging viruses allows us to highlight common features that may be of general validity and point out important challenges.
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Affiliation(s)
| | - Guttorm Haraldsen
- Department of Pathology, Oslo University Hospital, Oslo, Norway.,Department of Pathology, University of Oslo, Oslo, Norway
| | - Knut Falk
- Norwegian Veterinary Institute, Oslo, Norway.,AquaMed Consulting AS, Oslo, Norway
| | - Reidunn Edelmann
- Department of Clinical Medicine, Centre for Cancer Biomarkers CCBIO, University of Bergen, Bergen, Norway
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20
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Wong JJ, Chen Z, Chung JK, Groves JT, Jardetzky TS. EphrinB2 clustering by Nipah virus G is required to activate and trap F intermediates at supported lipid bilayer-cell interfaces. SCIENCE ADVANCES 2021; 7:eabe1235. [PMID: 33571127 PMCID: PMC7840137 DOI: 10.1126/sciadv.abe1235] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Accepted: 12/07/2020] [Indexed: 06/12/2023]
Abstract
Paramyxovirus membrane fusion requires an attachment protein that binds to a host cell receptor and a fusion protein that merges the viral and host membranes. For Nipah virus (NiV), the G attachment protein binds ephrinB2/B3 receptors and activates F-mediated fusion. To visualize dynamic events of these proteins at the membrane interface, we reconstituted NiV fusion activation by overlaying F- and G-expressing cells onto ephrinB2-functionalized supported lipid bilayers and used TIRF microscopy to follow F, G, and ephrinB2. We found that G and ephrinB2 form clusters and that oligomerization of ephrinB2 is necessary for F activation. Single-molecule tracking of F particles revealed accumulation of an immobilized intermediate upon activation. We found no evidence for stable F-G protein complexes before or after activation. These observations lead to a revised model for NiV fusion activation and provide a foundation for investigating other multicomponent viral fusion systems.
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Affiliation(s)
- Joyce J Wong
- Department of Structural Biology, Stanford University, Stanford, CA, USA
| | - Zhongwen Chen
- Multiscale Research Institute of Complex Systems, Fudan University, Shanghai, China
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA
| | - Jean K Chung
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA
| | - Jay T Groves
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA.
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Third Helical Domain of the Nipah Virus Fusion Glycoprotein Modulates both Early and Late Steps in the Membrane Fusion Cascade. J Virol 2020; 94:JVI.00644-20. [PMID: 32669342 DOI: 10.1128/jvi.00644-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 07/08/2020] [Indexed: 01/21/2023] Open
Abstract
Medically important paramyxoviruses, such as measles, mumps, parainfluenza, Nipah, and Hendra viruses, infect host cells by directing fusion of the viral and cellular plasma membranes. Upon infection, paramyxoviruses cause a second type of membrane fusion, cell-cell fusion (syncytium formation), which is linked to pathogenicity. Host cell receptor binding causes conformational changes in the attachment glycoprotein (HN, H, or G) that trigger a conformational cascade in the fusion (F) glycoprotein that mediates membrane fusion. F, a class I fusion protein, contains the archetypal heptad repeat regions 1 (HR1) and 2 (HR2). It is well established that binding of HR1 and HR2 is key to fusing viral and cellular membranes. In this study, we uncovered a novel fusion-modulatory role of a third structurally conserved helical region (HR3) in F. Based on its location within the F structure, and structural differences between its prefusion and postfusion conformations, we hypothesized that the HR3 modulates triggering of the F conformational cascade (still requiring G). We used the deadly Nipah virus (NiV) as an important paramyxoviral model to perform alanine scan mutagenesis and a series of multidisciplinary structural/functional analyses that dissect the various states of the membrane fusion cascade. Remarkably, we found that specific residues within the HR3 modulate not only early F-triggering but also late extensive fusion pore expansion steps in the membrane fusion cascade. Our results characterize these novel fusion-modulatory roles of the F HR3, improving our understanding of the membrane fusion process for NiV and likely for the related Henipavirus genus and possibly Paramyxoviridae family members.IMPORTANCE The Paramyxoviridae family includes important human and animal pathogens, such as measles, mumps, and parainfluenza viruses and the deadly henipaviruses Nipah (NiV) and Hendra (HeV) viruses. Paramyxoviruses infect the respiratory tract and the central nervous system (CNS) and can be highly infectious. Most paramyxoviruses have a limited host range. However, the biosafety level 4 NiV and HeV are highly pathogenic and have a wide mammalian host range. Nipah viral infections result in acute respiratory syndrome and severe encephalitis in humans, leading to 40 to 100% mortality rates. The lack of licensed vaccines or therapeutic approaches against NiV and other important paramyxoviruses underscores the need to understand viral entry mechanisms. In this study, we uncovered a novel role of a third helical region (HR3) of the NiV fusion glycoprotein in the membrane fusion process that leads to viral entry. This discovery sets HR3 as a new candidate target for antiviral strategies for NiV and likely for related viruses.
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Fischer K, Groschup MH, Diederich S. Importance of Endocytosis for the Biological Activity of Cedar Virus Fusion Protein. Cells 2020; 9:cells9092054. [PMID: 32911832 PMCID: PMC7565975 DOI: 10.3390/cells9092054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 09/03/2020] [Accepted: 09/04/2020] [Indexed: 01/02/2023] Open
Abstract
Endocytosis plays a particular role in the proteolytic activation of highly pathogenic henipaviruses Hendra (HeV) and Nipah virus (NiV) fusion (F) protein precursors. These proteins require endocytic uptake from the cell surface to be cleaved by cellular proteases within the endosomal compartment, followed by recycling to the plasma membrane for incorporation into budding virions or mediation of cell-cell fusion. This internalization largely depends on a tyrosine-based consensus motif for endocytosis present in the cytoplasmic tail of HeV and NiV F. Given the large number of tyrosine residues present in the F protein cytoplasmic domain of Cedar virus (CedV), a closely related but low pathogenic henipavirus, we aimed to investigate whether CedV F protein undergoes signal-mediated endocytosis from the cell surface controlled by tyrosine-based motifs present in its cytoplasmic tail and whether endocytosis is relevant for its biological activity. Therefore, tyrosine-based signals were mutated, and mutations were assessed for their effect on F cell surface expression, endocytosis, and biological activity. A membrane-proximal YXXΦ motif and a C-terminal di-tyrosine motif are of particular importance for cell surface expression and endocytosis rate. Furthermore, our data strongly indicate the pivotal role of endocytosis for the biological activity of the CedV F protein.
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Margolin EA, Strasser R, Chapman R, Williamson AL, Rybicki EP, Meyers AE. Engineering the Plant Secretory Pathway for the Production of Next-Generation Pharmaceuticals. Trends Biotechnol 2020; 38:1034-1044. [PMID: 32818443 DOI: 10.1016/j.tibtech.2020.03.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 03/06/2020] [Accepted: 03/06/2020] [Indexed: 02/06/2023]
Abstract
Production of biologics in plants, or plant molecular pharming, is a promising protein expression technology that is receiving increasing attention from the pharmaceutical industry. Previously, low expression yields of recombinant proteins and the realization that certain post-translational modifications (PTMs) may not occur optimally limited the widespread acceptance of the technology. However, molecular engineering of the plant secretory pathway is now enabling the production of increasingly complex biomolecules using tailored protein-specific approaches to ensure their maturation. These involve the elimination of undesired processing events, and the introduction of heterologous biosynthetic machinery to support the production of specific target proteins. Here, we discuss recent advances in the production of pharmaceutical proteins in plants, which leverage the unique advantages of the technology.
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Affiliation(s)
- Emmanuel A Margolin
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa; Wellcome Trust Centre for Infectious Disease Research in Africa, University of Cape Town, Cape Town, South Africa; Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa; Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa.
| | - Richard Strasser
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Ros Chapman
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa; Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Anna-Lise Williamson
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa; Wellcome Trust Centre for Infectious Disease Research in Africa, University of Cape Town, Cape Town, South Africa; Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Edward P Rybicki
- Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa; Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa; Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa
| | - Ann E Meyers
- Biopharming Research Unit, Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa
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Brenna S, Altmeppen HC, Mohammadi B, Rissiek B, Schlink F, Ludewig P, Krisp C, Schlüter H, Failla AV, Schneider C, Glatzel M, Puig B, Magnus T. Characterization of brain-derived extracellular vesicles reveals changes in cellular origin after stroke and enrichment of the prion protein with a potential role in cellular uptake. J Extracell Vesicles 2020; 9:1809065. [PMID: 32944194 PMCID: PMC7480459 DOI: 10.1080/20013078.2020.1809065] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 07/28/2020] [Accepted: 08/09/2020] [Indexed: 02/06/2023] Open
Abstract
Extracellular vesicles (EVs) are important means of intercellular communication and a potent tool for regenerative therapy. In ischaemic stroke, transient blockage of a brain artery leads to a lack of glucose and oxygen in the affected brain tissue, provoking neuronal death by necrosis in the core of the ischaemic region. The fate of neurons in the surrounding penumbra region depends on the stimuli, including EVs, received during the following hours. A detailed characterization of such stimuli is crucial not only for understanding stroke pathophysiology but also for new therapeutic interventions. In the present study, we characterize the EVs in mouse brain under physiological conditions and 24 h after induction of transient ischaemia in mice. We show that, in steady-state conditions, microglia are the main source of small EVs (sEVs), whereas after ischaemia the main sEV population originates from astrocytes. Brain sEVs presented high amounts of the prion protein (PrP), which were further increased after stroke. Moreover, EVs were enriched in a proteolytically truncated PrP fragment (PrP-C1). Because of similarities between PrP-C1 and certain viral surface proteins, we studied the cellular uptake of brain-derived sEVs from mice lacking (PrP-KO) or expressing PrP (WT). We show that PrP-KO-sEVs are taken up significantly faster and more efficiently than WT-EVs by primary neurons. Furthermore, microglia and astrocytes engulf PrP-KO-sEVs more readily than WT-sEVs. Our results provide novel information on the relative contribution of brain cell types to the sEV pool in murine brain and indicate that increased release of sEVs by astrocytes together with elevated levels of PrP in sEVs may play a role in intercellular communication at early stages after stroke. In addition, amounts of PrP (and probably PrP-C1) in brain sEVs seem to contribute to regulating their cellular uptake.
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Affiliation(s)
- Santra Brenna
- Neurology Department, Experimental Research in Stroke and Inflammation, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Hermann C. Altmeppen
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Behnam Mohammadi
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Björn Rissiek
- Neurology Department, Experimental Research in Stroke and Inflammation, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Florence Schlink
- Neurology Department, Experimental Research in Stroke and Inflammation, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Peter Ludewig
- Neurology Department, Experimental Research in Stroke and Inflammation, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christoph Krisp
- Institute of Clinical Chemistry and Laboratory Medicine, Mass Spectrometric Proteomics University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Hartmut Schlüter
- Institute of Clinical Chemistry and Laboratory Medicine, Mass Spectrometric Proteomics University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Antonio Virgilio Failla
- UKE Microscopy Imaging Facility, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Carola Schneider
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Markus Glatzel
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Berta Puig
- Neurology Department, Experimental Research in Stroke and Inflammation, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tim Magnus
- Neurology Department, Experimental Research in Stroke and Inflammation, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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Cannalire R, Stefanelli I, Cerchia C, Beccari AR, Pelliccia S, Summa V. SARS-CoV-2 Entry Inhibitors: Small Molecules and Peptides Targeting Virus or Host Cells. Int J Mol Sci 2020; 21:ijms21165707. [PMID: 32784899 PMCID: PMC7460888 DOI: 10.3390/ijms21165707] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 08/07/2020] [Accepted: 08/07/2020] [Indexed: 12/12/2022] Open
Abstract
The pandemic evolution of SARS-CoV-2 infection is forcing the scientific community to unprecedented efforts to explore all possible approaches against COVID-19. In this context, targeting virus entry is a promising antiviral strategy for controlling viral infections. The main strategies pursued to inhibit the viral entry are considering both the virus and the host factors involved in the process. Primarily, direct-acting antivirals rely on inhibition of the interaction between ACE2 and the receptor binding domain (RBD) of the Spike (S) protein or targeting the more conserved heptad repeats (HRs), involved in the membrane fusion process. The inhibition of host TMPRSS2 and cathepsins B/L may represent a complementary strategy to be investigated. In this review, we discuss the development entry inhibitors targeting the S protein, as well as the most promising host targeting strategies involving TMPRSS2 and CatB/L, which have been exploited so far against CoVs and other related viruses.
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Affiliation(s)
- Rolando Cannalire
- Department of Pharmacy, University of Napoli “Federico II”, via D. Montesano 49, 80131 Napoli, Italy; (R.C.); (I.S.); (C.C.); (S.P.)
| | - Irina Stefanelli
- Department of Pharmacy, University of Napoli “Federico II”, via D. Montesano 49, 80131 Napoli, Italy; (R.C.); (I.S.); (C.C.); (S.P.)
| | - Carmen Cerchia
- Department of Pharmacy, University of Napoli “Federico II”, via D. Montesano 49, 80131 Napoli, Italy; (R.C.); (I.S.); (C.C.); (S.P.)
| | | | - Sveva Pelliccia
- Department of Pharmacy, University of Napoli “Federico II”, via D. Montesano 49, 80131 Napoli, Italy; (R.C.); (I.S.); (C.C.); (S.P.)
| | - Vincenzo Summa
- Department of Pharmacy, University of Napoli “Federico II”, via D. Montesano 49, 80131 Napoli, Italy; (R.C.); (I.S.); (C.C.); (S.P.)
- Correspondence: ; Tel.: +39-081-678656
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Dash RN, Moharana AK, Subudhi BB. Sulfonamides: Antiviral Strategy for Neglected Tropical Disease Virus. CURR ORG CHEM 2020. [DOI: 10.2174/1385272824999200515094100] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The viral infections are a threat to the health system around the globe. Although
more than 60 antiviral drugs have been approved by the FDA, most of them are for the
management of few viruses like HIV, Hepatitis and Influenza. There is no antiviral for
many viruses including Dengue, Chikungunya and Japanese encephalitis. Many of these
neglected viruses are increasingly becoming global pathogens. Lack of broad spectrum of
action and the rapid rise of resistance and cross-resistance to existing antiviral have further
increased the challenge of antiviral development. Sulfonamide, as a privileged scaffold,
has been capitalized to develop several bioactive compounds and drugs. Accordingly, several
reviews have been published in recent times on bioactive sulfonamides. However,
there are not enough review reports of antiviral sulfonamides in the last five years. Sulfonamides
scaffolds have received sufficient attention for the development of non- nucleoside antivirals following
the emergence of cross-resistance to nucleoside inhibitors. Hybridization of bioactive pharmacophores
with sulfonamides has been used as a strategy to develop sulfonamide antivirals. This review is an effort to
analyze these attempts and evaluate their translational potential. Parameters including potency (IC50), toxicity
(CC50) and selectivity (CC50/IC50) have been used in this report to suggest the potential of sulfonamide derivatives
to progress further as antiviral. Since most of these antiviral properties are based on the in vitro results,
the drug-likeness of molecules has been predicted to propose in vivo potential. The structure-activity relationship
has been analyzed to encourage further optimization of antiviral properties.
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Affiliation(s)
- Rudra Narayan Dash
- Drug Development and Analysis Laboratory, School of Pharmaceutical Sciences, Siksha ‘O’ Anusandhan (Deemed to be University), Bhubaneswar-751029, Odisha, India
| | - Alok Kumar Moharana
- Drug Development and Analysis Laboratory, School of Pharmaceutical Sciences, Siksha ‘O’ Anusandhan (Deemed to be University), Bhubaneswar-751029, Odisha, India
| | - Bharat Bhusan Subudhi
- Drug Development and Analysis Laboratory, School of Pharmaceutical Sciences, Siksha ‘O’ Anusandhan (Deemed to be University), Bhubaneswar-751029, Odisha, India
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27
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Barrett CT, Dutch RE. Viral Membrane Fusion and the Transmembrane Domain. Viruses 2020; 12:v12070693. [PMID: 32604992 PMCID: PMC7412173 DOI: 10.3390/v12070693] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 06/24/2020] [Accepted: 06/25/2020] [Indexed: 01/05/2023] Open
Abstract
Initiation of host cell infection by an enveloped virus requires a viral-to-host cell membrane fusion event. This event is mediated by at least one viral transmembrane glycoprotein, termed the fusion protein, which is a key therapeutic target. Viral fusion proteins have been studied for decades, and numerous critical insights into their function have been elucidated. However, the transmembrane region remains one of the most poorly understood facets of these proteins. In the past ten years, the field has made significant advances in understanding the role of the membrane-spanning region of viral fusion proteins. We summarize developments made in the past decade that have contributed to the understanding of the transmembrane region of viral fusion proteins, highlighting not only their critical role in the membrane fusion process, but further demonstrating their involvement in several aspects of the viral lifecycle.
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28
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Branttie JM, Dutch RE. Parainfluenza virus 5 fusion protein maintains pre-fusion stability but not fusogenic activity following mutation of a transmembrane leucine/isoleucine domain. J Gen Virol 2020; 101:467-472. [PMID: 32100701 DOI: 10.1099/jgv.0.001399] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The paramyxoviruses Hendra virus (HeV) and parainfluenza virus 5 (PIV5) require the fusion (F) protein to efficiently infect cells. For fusion to occur, F undergoes dramatic, essentially irreversible conformational changes to merge the viral and cell membranes into a continuous bilayer. Recently, a transmembrane (TM) domain leucine/isoleucine (L/I) zipper was shown to be critical in maintaining the expression, stability and pre-fusion conformation of HeV F, allowing for fine-tuned timing of membrane fusion. To analyse the effect of the TM domain L/I zipper in another paramyxovirus, we created alanine mutations to the TM domain of PIV5 F, a paramyxovirus model system. Our data show that while the PIV5 F TM L/I zipper does not significantly affect total expression and only modestly affects surface expression and pre-fusion stability, it is critical for fusogenic activity. These results suggest that the roles of TM L/I zipper motifs differ among members of the family Paramyxoviridae.
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Affiliation(s)
- Jean Mawuena Branttie
- Department of Molecular and Cellular Biochemistry, College of Medicine University of Kentucky Biomedical Biological Sciences Research Bldg, 741 South Limestone Street, Lexington, KY, USA
| | - Rebecca Ellis Dutch
- Department of Molecular and Cellular Biochemistry, College of Medicine University of Kentucky Biomedical Biological Sciences Research Bldg, 741 South Limestone Street, Lexington, KY, USA
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29
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Azarm KD, Lee B. Differential Features of Fusion Activation within the Paramyxoviridae. Viruses 2020; 12:v12020161. [PMID: 32019182 PMCID: PMC7077268 DOI: 10.3390/v12020161] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 01/25/2020] [Accepted: 01/29/2020] [Indexed: 12/13/2022] Open
Abstract
Paramyxovirus (PMV) entry requires the coordinated action of two envelope glycoproteins, the receptor binding protein (RBP) and fusion protein (F). The sequence of events that occurs during the PMV entry process is tightly regulated. This regulation ensures entry will only initiate when the virion is in the vicinity of a target cell membrane. Here, we review recent structural and mechanistic studies to delineate the entry features that are shared and distinct amongst the Paramyxoviridae. In general, we observe overarching distinctions between the protein-using RBPs and the sialic acid- (SA-) using RBPs, including how their stalk domains differentially trigger F. Moreover, through sequence comparisons, we identify greater structural and functional conservation amongst the PMV fusion proteins, as compared to the RBPs. When examining the relative contributions to sequence conservation of the globular head versus stalk domains of the RBP, we observe that, for the protein-using PMVs, the stalk domains exhibit higher conservation and find the opposite trend is true for SA-using PMVs. A better understanding of conserved and distinct features that govern the entry of protein-using versus SA-using PMVs will inform the rational design of broader spectrum therapeutics that impede this process.
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30
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Navaratnarajah CK, Generous AR, Yousaf I, Cattaneo R. Receptor-mediated cell entry of paramyxoviruses: Mechanisms, and consequences for tropism and pathogenesis. J Biol Chem 2020; 295:2771-2786. [PMID: 31949044 DOI: 10.1074/jbc.rev119.009961] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Research in the last decade has uncovered many new paramyxoviruses, airborne agents that cause epidemic diseases in animals including humans. Most paramyxoviruses enter epithelial cells of the airway using sialic acid as a receptor and cause only mild disease. However, others cross the epithelial barrier and cause more severe disease. For some of these viruses, the host receptors have been identified, and the mechanisms of cell entry have been elucidated. The tetrameric attachment proteins of paramyxoviruses have vastly different binding affinities for their cognate receptors, which they contact through different binding surfaces. Nevertheless, all input signals are converted to the same output: conformational changes that trigger refolding of trimeric fusion proteins and membrane fusion. Experiments with selectively receptor-blinded viruses inoculated into their natural hosts have provided insights into tropism, identifying the cells and tissues that support growth and revealing the mechanisms of pathogenesis. These analyses also shed light on diabolically elegant mechanisms used by morbilliviruses, including the measles virus, to promote massive amplification within the host, followed by efficient aerosolization and rapid spread through host populations. In another paradigm of receptor-facilitated severe disease, henipaviruses, including Nipah and Hendra viruses, use different members of one protein family to cause zoonoses. Specific properties of different paramyxoviruses, like neurotoxicity and immunosuppression, are now understood in the light of receptor specificity. We propose that research on the specific receptors for several newly identified members of the Paramyxoviridae family that may not bind sialic acid is needed to anticipate their zoonotic potential and to generate effective vaccines and antiviral compounds.
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Affiliation(s)
| | - Alex R Generous
- Mayo Clinic Graduate School of Biomedical Sciences, Virology and Gene Therapy Track, Mayo Clinic, Rochester, Minnesota 55905
| | - Iris Yousaf
- Mayo Clinic Graduate School of Biomedical Sciences, Virology and Gene Therapy Track, Mayo Clinic, Rochester, Minnesota 55905
| | - Roberto Cattaneo
- Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota 55905.
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A structural basis for antibody-mediated neutralization of Nipah virus reveals a site of vulnerability at the fusion glycoprotein apex. Proc Natl Acad Sci U S A 2019; 116:25057-25067. [PMID: 31767754 PMCID: PMC6911215 DOI: 10.1073/pnas.1912503116] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Nipah virus (NiV) is a highly pathogenic paramyxovirus that causes frequent outbreaks of severe neurologic and respiratory disease in humans with high case fatality rates. The 2 glycoproteins displayed on the surface of the virus, NiV-G and NiV-F, mediate host-cell attachment and membrane fusion, respectively, and are targets of the host antibody response. Here, we provide a molecular basis for neutralization of NiV through antibody-mediated targeting of NiV-F. Structural characterization of a neutralizing antibody (nAb) in complex with trimeric prefusion NiV-F reveals an epitope at the membrane-distal domain III (DIII) of the molecule, a region that undergoes substantial refolding during host-cell entry. The epitope of this monoclonal antibody (mAb66) is primarily protein-specific and we observe that glycosylation at the periphery of the interface likely does not inhibit mAb66 binding to NiV-F. Further characterization reveals that a Hendra virus-F-specific nAb (mAb36) and many antibodies in an antihenipavirus-F polyclonal antibody mixture (pAb835) also target this region of the molecule. Integrated with previously reported paramyxovirus F-nAb structures, these data support a model whereby the membrane-distal region of the F protein is targeted by the antibody-mediated immune response across henipaviruses. Notably, our domain-specific sequence analysis reveals no evidence of selective pressure at this region of the molecule, suggestive that functional constraints prevent immune-driven sequence variation. Combined, our data reveal the membrane-distal region of NiV-F as a site of vulnerability on the NiV surface.
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32
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Bhattacharya S, Dhar S, Banerjee A, Ray S. Detailed Molecular Biochemistry for Novel Therapeutic Design Against Nipah and Hendra Virus: A Systematic Review. Curr Mol Pharmacol 2019; 13:108-125. [PMID: 31657692 DOI: 10.2174/1874467212666191023123732] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Revised: 10/13/2019] [Accepted: 10/15/2019] [Indexed: 11/22/2022]
Abstract
BACKGROUND Nipah virus (NiV) and Hendra virus (HeV) of genus Henipavirus are the deadliest zoonotic viruses, which cause severe respiratory ailments and fatal encephalitis in humans and other susceptible animals. The fatality rate for these infections had been alarmingly high with no approved treatment available to date. Viral attachment and fusion with host cell membrane is essential for viral entry and is the most essential event of viral infection. Viral attachment is mediated by interaction of Henipavirus attachment glycoprotein (G) with the host cell receptor: Ephrin B2/B3, while viral fusion and endocytosis are mediated by the combined action of both viral glycoprotein (G) and fusion protein (F). CONCLUSION This review highlights the mechanism of viral attachment, fusion and also explains the basic mechanism and pathobiology of this infection in humans. The drugs and therapeutics used either experimentally or clinically against NiV and HeV infection have been documented and classified in detail. Some amino acid residues essential for the functionality of G and F proteins were also emphasized. Therapeutic designing to target and block these residues can serve as a promising approach in future drug development against NiV and HeV.
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Affiliation(s)
| | - Shreyeshi Dhar
- Amity Institute of Biotechnology, Amity University, Kolkata, India
| | - Arundhati Banerjee
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani, Nadia, India
| | - Sujay Ray
- Amity Institute of Biotechnology, Amity University, Kolkata, India
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Analysis of Resistance of Ebola Virus Glycoprotein-Driven Entry Against MDL28170, An Inhibitor of Cysteine Cathepsins. Pathogens 2019; 8:pathogens8040192. [PMID: 31618932 PMCID: PMC6963435 DOI: 10.3390/pathogens8040192] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 09/26/2019] [Accepted: 10/12/2019] [Indexed: 12/14/2022] Open
Abstract
Ebola virus (EBOV) infection can cause severe and frequently fatal disease in human patients. The EBOV glycoprotein (GP) mediates viral entry into host cells. For this, GP depends on priming by the pH-dependent endolysosomal cysteine proteases cathepsin B (CatB) and, to a lesser degree, cathepsin L (CatL), at least in most cell culture systems. However, there is limited information on whether and how EBOV-GP can acquire resistance to CatB/L inhibitors. Here, we addressed this question using replication-competent vesicular stomatitis virus bearing EBOV-GP. Five passages of this virus in the presence of the CatB/CatL inhibitor MDL28170 were sufficient to select resistant viral variants and sequencing revealed that all GP sequences contained a V37A mutation, which, in the context of native GP, is located in the base of the GP surface unit. In addition, some GP sequences harbored mutation S195R in the receptor-binding domain. Finally, mutational analysis demonstrated that V37A but not S195R conferred resistance against MDL28170 and other CatB/CatL inhibitors. Collectively, a single amino acid substitution in GP is sufficient to confer resistance against CatB/CatL inhibitors, suggesting that usage of CatB/CatL inhibitors for antiviral therapy may rapidly select for resistant viral variants.
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An antibody against the F glycoprotein inhibits Nipah and Hendra virus infections. Nat Struct Mol Biol 2019; 26:980-987. [PMID: 31570878 PMCID: PMC6858553 DOI: 10.1038/s41594-019-0308-9] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 08/21/2019] [Indexed: 12/02/2022]
Abstract
Nipah virus (NiV) and Hendra virus (HeV) are zoonotic henipaviruses (HNVs) responsible for outbreaks of encephalitis and respiratory illness with fatality rates of 50–100%. No vaccines or licensed therapeutics currently exist to protect humans against NiV or HeV. HNVs enter host cells by fusing the viral and cellular membranes via the concerted action of the attachment (G) and fusion (F) glycoproteins, the main targets of the humoral immune response. Here, we describe the isolation and humanization of a potent monoclonal antibody cross-neutralizing NiV and HeV. Cryo-electron microscopy, triggering and fusion studies show the antibody binds to a prefusion-specific quaternary epitope, conserved in NiV F and HeV F glycoproteins, and prevents membrane fusion and viral entry. This work supports the importance of the HNV prefusion F conformation for eliciting a robust immune response and paves the way for using this antibody for prophylaxis and post-exposure therapy with NiV- and HeV-infected individuals. An antibody that recognizes the F glycoproteins from Nipah and Hendra viruses can neutralize both viruses and recognizes a quaternary epitope in the prefusion F trimer, preventing conformational changes required for fusion.
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Ramharack P, Devnarain N, Shunmugam L, Soliman MES. Navigating Research Toward the Re-emerging Nipah Virus- A New Piece to the Puzzle. Curr Pharm Des 2019; 25:1392-1401. [PMID: 31258065 DOI: 10.2174/1381612825666190620104203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 05/22/2019] [Indexed: 11/22/2022]
Abstract
BACKGROUND The recent Nipah virus (NiV) outbreak in India has caused a state of chaos, with potential to become the next international pandemic. There is still a great deal to learn about NiV for the development of a potent treatment against it. The NiV non-structural proteins play important roles in the lifecycle of the virus, with the RNA-dependent RNA-polymerase (RdRp) being a vital component in viral replication. In this study, we not only provide a comprehensive overview of all the literature concerning NiV, we also propose a model of the NiV RdRp and screen for potential inhibitors of the viral enzyme. METHODS In this study, computational tools were utilized in the design of a NiV RdRp homology model. The active site of RdRp was then identified and potential inhibitors of the protein were discovered with the use of pharmacophore-based screening. RESULTS Ramachandran plot analysis revealed a favourable model. Upon binding of nucleoside analog, 4'- Azidocytidine, active site residues Trp1714 and Ser1713 took part in stabilizing hydrogen bonds, while Thr1716, Ser1478, Ser1476 and Glu1465 contributed to hydrophobic interactions. Pharmacophore based screening yielded 18 hits, of which ZINC00085930 demonstrated the most optimal binding energy (-8.1 kcal/mol), validating its use for further analysis as an inhibitor of NiV. CONCLUSION In this study we provide a critical guide, elucidating on the in silico requirements of the drug design and discovery process against NiV. This material lays a foundation for future research into the design and development of drugs that inhibit NiV.
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Affiliation(s)
- Pritika Ramharack
- Molecular Bio-computation and Drug Design Laboratory, School of Health Sciences, University of KwaZulu-Natal, Westville Campus, Durban 4001, South Africa
| | - Nikita Devnarain
- Molecular Bio-computation and Drug Design Laboratory, School of Health Sciences, University of KwaZulu-Natal, Westville Campus, Durban 4001, South Africa
| | - Letitia Shunmugam
- Molecular Bio-computation and Drug Design Laboratory, School of Health Sciences, University of KwaZulu-Natal, Westville Campus, Durban 4001, South Africa
| | - Mahmoud E S Soliman
- Molecular Bio-computation and Drug Design Laboratory, School of Health Sciences, University of KwaZulu-Natal, Westville Campus, Durban 4001, South Africa
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Ringel M, Heiner A, Behner L, Halwe S, Sauerhering L, Becker N, Dietzel E, Sawatsky B, Kolesnikova L, Maisner A. Nipah virus induces two inclusion body populations: Identification of novel inclusions at the plasma membrane. PLoS Pathog 2019; 15:e1007733. [PMID: 31034506 PMCID: PMC6488097 DOI: 10.1371/journal.ppat.1007733] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 03/26/2019] [Indexed: 01/31/2023] Open
Abstract
Formation of cytoplasmic inclusion bodies (IBs) is a hallmark of infections with non-segmented negative-strand RNA viruses (order Mononegavirales). We show here that Nipah virus (NiV), a bat-derived highly pathogenic member of the Paramyxoviridae family, differs from mononegaviruses of the Rhabdo-, Filo- and Pneumoviridae families by forming two types of IBs with distinct localizations, formation kinetics, and protein compositions. IBs in the perinuclear region form rapidly upon expression of the nucleocapsid proteins. These IBperi are highly mobile and associate with the aggresome marker y-tubulin. IBperi can recruit unrelated overexpressed cytosolic proteins but do not contain the viral matrix (M) protein. Additionally, NiV forms an as yet undescribed IB population at the plasma membrane (IBPM) that is y-tubulin-negative but contains the M protein. Infection studies with recombinant NiV revealed that IBPM require the M protein for their formation, and most likely represent sites of NiV assembly and budding. The identification of this novel type of plasma membrane-associated IBs not only provides new insights into NiV biology and may open new avenues to develop novel antiviral approaches to treat these highly pathogenic viruses, it also provides a basis for a more detailed characterization of IBs and their role in virus assembly and replication in infections with other Mononegavirales. Inclusion bodies (IBs) induced by non-segmented negative-strand RNA viruses (Mononegavirales) are described as mobile cytosolic compartments that concentrate viral proteins and represent the main viral replication sites in infected cells. This general concept is mainly based on studies with mononegaviruses from the Rhabdo-, Filo- and Pneumoviridae families. IBs induced by members of the Paramyxoviridae family are much less well characterized, and this study provides evidence that paramyxoviral IBs may have different compositions and functions. The main finding of this study is that Nipah virus (NiV), a highly pathogenic member of the genus Henipavirus in the family Paramyxoviridae, forms a novel type of IB whose formation at plasma membrane assembly sites depends on the viral matrix protein, and suggests a role for IBs not yet described for other Mononegavirales. This discovery clearly extents the current concept of IB functions and illustrates the need to further investigate IBs formed by other paramyxoviruses.
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Affiliation(s)
- Marc Ringel
- Institute of Virology, Philipps University Marburg, Marburg, Germany
| | - Anja Heiner
- Institute of Virology, Philipps University Marburg, Marburg, Germany
| | - Laura Behner
- Institute of Virology, Philipps University Marburg, Marburg, Germany
| | - Sandro Halwe
- Institute of Virology, Philipps University Marburg, Marburg, Germany
| | - Lucie Sauerhering
- Institute of Virology, Philipps University Marburg, Marburg, Germany
| | - Nico Becker
- Institute of Virology, Philipps University Marburg, Marburg, Germany
| | - Erik Dietzel
- Institute of Virology, Philipps University Marburg, Marburg, Germany
| | - Bevan Sawatsky
- Division of Veterinary Medicine, Paul-Ehrlich-Institut, Langen, Germany
| | | | - Andrea Maisner
- Institute of Virology, Philipps University Marburg, Marburg, Germany
- * E-mail:
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Calu-3 cells are largely resistant to entry driven by filovirus glycoproteins and the entry defect can be rescued by directed expression of DC-SIGN or cathepsin L. Virology 2019; 532:22-29. [PMID: 30999160 PMCID: PMC7112014 DOI: 10.1016/j.virol.2019.03.020] [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: 01/09/2019] [Revised: 03/25/2019] [Accepted: 03/28/2019] [Indexed: 12/12/2022]
Abstract
Priming of the viral glycoprotein (GP) by the cellular proteases cathepsin B and L (CatB, CatL) is believed to be essential for cell entry of filoviruses. However, pseudotyping systems that predominantly produce non-filamentous particles have frequently been used to prove this concept. Here, we report that GP-mediated entry of retroviral-, rhabdoviral and filoviral particles depends on CatB/CatL activity and that this effect is cell line-independent. Moreover, we show that the human cell line Calu-3, which expresses low amounts of CatL, is largely resistant to entry driven by diverse filovirus GPs. Finally, we demonstrate that Calu-3 cell entry mediated by certain filovirus GPs can be rescued upon directed expression of CatL or DC-SIGN. Our results identify Calu-3 cells as largely resistant to filovirus GP-driven entry and demonstrate that entry is limited at the stage of virion attachment and GP priming.
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Behner L, Zimmermann L, Ringel M, Weis M, Maisner A. Formation of high-order oligomers is required for functional bioactivity of an African bat henipavirus surface glycoprotein. Vet Microbiol 2018; 218:90-97. [DOI: 10.1016/j.vetmic.2018.03.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Revised: 03/29/2018] [Accepted: 03/31/2018] [Indexed: 10/17/2022]
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Host Cell Proteases: Cathepsins. ACTIVATION OF VIRUSES BY HOST PROTEASES 2018. [PMCID: PMC7123490 DOI: 10.1007/978-3-319-75474-1_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Cathepsins are proteolytic enzymes with a broad spectrum of substrates. They are known to reside within endo-lysosomes where they acquire optimal conditions for proteolytic activity and substrate cleavage. However, cathepsins have been detected in locations other than the canonical compartments of the endocytotic pathway. They are often secreted from cells in either proteolytically inactive proform or as mature and active enzyme; this may happen in both physiological and pathological conditions. Moreover, cytosolic and nuclear forms of cathepsins have been described and are currently an emerging field of research aiming at understanding their functions in such unexpected cellular locations. This chapter summarizes the canonical pathways of biosynthesis and transport of cathepsins in healthy cells. We further describe how cathepsins can reach unexpected locations such as the extracellular space or the cytosol and the nuclear matrix. No matter where viruses and cathepsins encounter, several outcomes can be perceived. Thus, scenarios are discussed on how cathepsins may support virus entry into host cells, involve in viral fusion factor and polyprotein processing in different host cell compartments, or help in packaging of viral particles during maturation. It is of note to mention that this review is not meant to comprehensively cover the present literature on viruses encountering cathepsins but rather illustrates, on some representative examples, the possible roles of cathepsins in replication of viruses and in the course of disease.
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Mutations in the Transmembrane Domain and Cytoplasmic Tail of Hendra Virus Fusion Protein Disrupt Virus-Like-Particle Assembly. J Virol 2017; 91:JVI.00152-17. [PMID: 28468881 DOI: 10.1128/jvi.00152-17] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 04/12/2017] [Indexed: 12/13/2022] Open
Abstract
Hendra virus (HeV) is a zoonotic paramyxovirus that causes deadly illness in horses and humans. An intriguing feature of HeV is the utilization of endosomal protease for activation of the viral fusion protein (F). Here we investigated how endosomal F trafficking affects HeV assembly. We found that the HeV matrix (M) and F proteins each induced particle release when they were expressed alone but that their coexpression led to coordinated assembly of virus-like particles (VLPs) that were morphologically and physically distinct from M-only or F-only VLPs. Mutations to the F protein transmembrane domain or cytoplasmic tail that disrupted endocytic trafficking led to failure of F to function with M for VLP assembly. Wild-type F functioned normally for VLP assembly even when its cleavage was prevented with a cathepsin inhibitor, indicating that it is endocytic F trafficking that is important for VLP assembly, not proteolytic F cleavage. Under specific conditions of reduced M expression, we found that M could no longer induce significant VLP release but retained the ability to be incorporated as a passenger into F-driven VLPs, provided that the F protein was competent for endocytic trafficking. The F and M proteins were both found to traffic through Rab11-positive recycling endosomes (REs), suggesting a model in which F and M trafficking pathways converge at REs, enabling these proteins to preassemble before arriving at plasma membrane budding sites.IMPORTANCE Hendra virus and Nipah virus are zoonotic paramyxoviruses that cause lethal infections in humans. Unlike that for most paramyxoviruses, activation of the henipavirus fusion protein occurs in recycling endosomal compartments. In this study, we demonstrate that the unique endocytic trafficking pathway of Hendra virus F protein is required for proper viral assembly and particle release. These results advance our basic understanding of the henipavirus assembly process and provide a novel model for the interplay between glycoprotein trafficking and paramyxovirus assembly.
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Webb S, Nagy T, Moseley H, Fried M, Dutch R. Hendra virus fusion protein transmembrane domain contributes to pre-fusion protein stability. J Biol Chem 2017; 292:5685-5694. [PMID: 28213515 DOI: 10.1074/jbc.m117.777235] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 02/15/2017] [Indexed: 12/29/2022] Open
Abstract
Enveloped viruses utilize fusion (F) proteins studding the surface of the virus to facilitate membrane fusion with a target cell membrane. Fusion of the viral envelope with a cellular membrane is required for release of viral genomic material, so the virus can ultimately reproduce and spread. To drive fusion, the F protein undergoes an irreversible conformational change, transitioning from a metastable pre-fusion conformation to a more thermodynamically stable post-fusion structure. Understanding the elements that control stability of the pre-fusion state and triggering to the post-fusion conformation is important for understanding F protein function. Mutations in F protein transmembrane (TM) domains implicated the TM domain in the fusion process, but the structural and molecular details in fusion remain unclear. Previously, analytical ultracentrifugation was utilized to demonstrate that isolated TM domains of Hendra virus F protein associate in a monomer-trimer equilibrium (Smith, E. C., Smith, S. E., Carter, J. R., Webb, S. R., Gibson, K. M., Hellman, L. M., Fried, M. G., and Dutch, R. E. (2013) J. Biol. Chem. 288, 35726-35735). To determine factors driving this association, 140 paramyxovirus F protein TM domain sequences were analyzed. A heptad repeat of β-branched residues was found, and analysis of the Hendra virus F TM domain revealed a heptad repeat leucine-isoleucine zipper motif (LIZ). Replacement of the LIZ with alanine resulted in dramatically reduced TM-TM association. Mutation of the LIZ in the whole protein resulted in decreased protein stability, including pre-fusion conformation stability. Together, our data suggest that the heptad repeat LIZ contributed to TM-TM association and is important for F protein function and pre-fusion stability.
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Affiliation(s)
- Stacy Webb
- From the Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536
| | - Tamas Nagy
- From the Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536
| | - Hunter Moseley
- From the Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536
| | - Michael Fried
- From the Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536
| | - Rebecca Dutch
- From the Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536
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Abstract
INTRODUCTION Cathepsins play an important role in protein degradation and processing. Aberrant cathepsin B or L is closely associated with many serious diseases such as cancer, osteoporosis and autoimmune disorders. Therefore, development of potent and selective cathepsin B and L inhibitors has aroused much attention in recent years. Although several classes of cathepsin inhibitors are presently available, there are still some problems to solve, such as broad-spectrum inhibition to protease, specially cysteine proteases, which lead to unpredictable side effects in clinical trials. Therefore, it is very necessary to discovery new scaffolds and new application of cathepsin B and L inhibitors for developing therapeutic agents for treating diseases mediated by cathepsin B or L. Areas covered: This updated review summarizes new patents on cathepsin B and L inhibitors from 2010 to present. Expert opinion: The review gives the latest development in the area of inhibitors of cathepsin B and L, which have been considered key therapeutic targets for the development of drugs treating related diseases. This review puts emphasis on the discovery of novel small molecule inhibitors of cathepsin B and L, as well as their new application as new therapeutic agents.
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Affiliation(s)
- Yu-Yao Li
- a College of Pharmaceutical Science , Soochow University , Suzhou , PR China
| | - Jing Fang
- a College of Pharmaceutical Science , Soochow University , Suzhou , PR China
| | - Gui-Zhen Ao
- a College of Pharmaceutical Science , Soochow University , Suzhou , PR China
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Multiple Strategies Reveal a Bidentate Interaction between the Nipah Virus Attachment and Fusion Glycoproteins. J Virol 2016; 90:10762-10773. [PMID: 27654290 DOI: 10.1128/jvi.01469-16] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 09/14/2016] [Indexed: 11/20/2022] Open
Abstract
The paramyxoviral family contains many medically important viruses, including measles virus, mumps virus, parainfluenza viruses, respiratory syncytial virus, human metapneumovirus, and the deadly zoonotic henipaviruses Hendra and Nipah virus (NiV). To both enter host cells and spread from cell to cell within infected hosts, the vast majority of paramyxoviruses utilize two viral envelope glycoproteins: the attachment glycoprotein (G, H, or hemagglutinin-neuraminidase [HN]) and the fusion glycoprotein (F). Binding of G/H/HN to a host cell receptor triggers structural changes in G/H/HN that in turn trigger F to undergo a series of conformational changes that result in virus-cell (viral entry) or cell-cell (syncytium formation) membrane fusion. The actual regions of G/H/HN and F that interact during the membrane fusion process remain relatively unknown though it is generally thought that the paramyxoviral G/H/HN stalk region interacts with the F head region. Studies to determine such interactive regions have relied heavily on coimmunoprecipitation approaches, whose limitations include the use of detergents and the micelle-mediated association of proteins. Here, we developed a flow-cytometric strategy capable of detecting membrane protein-protein interactions by interchangeably using the full-length form of G and a soluble form of F, or vice versa. Using both coimmunoprecipitation and flow-cytometric strategies, we found a bidentate interaction between NiV G and F, where both the stalk and head regions of NiV G interact with F. This is a new structural-biological finding for the paramyxoviruses. Additionally, our studies disclosed regions of the NiV G and F glycoproteins dispensable for the G and F interactions. IMPORTANCE Nipah virus (NiV) is a zoonotic paramyxovirus that causes high mortality rates in humans, with no approved treatment or vaccine available for human use. Viral entry into host cells relies on two viral envelope glycoproteins: the attachment (G) and fusion (F) glycoproteins. Binding of G to the ephrinB2 or ephrinB3 cell receptors triggers conformational changes in G that in turn cause F to undergo conformational changes that result in virus-host cell membrane fusion and viral entry. It is currently unknown, however, which specific regions of G and F interact during membrane fusion. Past efforts to determine the interacting regions have relied mainly on coimmunoprecipitation, a technique with some pitfalls. We developed a flow-cytometric assay to study membrane protein-protein interactions, and using this assay we report a bidentate interaction whereby both the head and stalk regions of NiV G interact with NiV F, a new finding for the paramyxovirus family.
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Sauerhering L, Zickler M, Elvert M, Behner L, Matrosovich T, Erbar S, Matrosovich M, Maisner A. Species-specific and individual differences in Nipah virus replication in porcine and human airway epithelial cells. J Gen Virol 2016; 97:1511-1519. [PMID: 27075405 DOI: 10.1099/jgv.0.000483] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Highly pathogenic Nipah virus (NiV) causes symptomatic infections in pigs and humans. The severity of respiratory symptoms is much more pronounced in pigs than in humans, suggesting species-specific differences of NiV replication in porcine and human airways. Here, we present a comparative study on productive NiV replication in primary airway epithelial cell cultures of the two species. We reveal that NiV growth substantially differs in primary cells between pigs and humans, with a more rapid spread of infection in human airway epithelia. Increased replication, correlated with higher endogenous expression levels of the main NiV entry receptor ephrin-B2, not only significantly differed between airway cells of the two species but also varied between cells from different human donors. To our knowledge, our study provides the first experimental evidence of species-specific and individual differences in NiV receptor expression and replication kinetics in primary airway epithelial cells. It remains to be determined whether and how these differences contribute to the viral host range and pathogenicity.
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Affiliation(s)
- Lucie Sauerhering
- Institute of Virology, Philipps University Marburg, Marburg, Germany
| | - Martin Zickler
- Institute of Virology, Philipps University Marburg, Marburg, Germany
| | - Mareike Elvert
- Institute of Virology, Philipps University Marburg, Marburg, Germany
| | - Laura Behner
- Institute of Virology, Philipps University Marburg, Marburg, Germany
| | | | - Stephanie Erbar
- Institute of Virology, Philipps University Marburg, Marburg, Germany
| | | | - Andrea Maisner
- Institute of Virology, Philipps University Marburg, Marburg, Germany
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White JM, Whittaker GR. Fusion of Enveloped Viruses in Endosomes. Traffic 2016; 17:593-614. [PMID: 26935856 PMCID: PMC4866878 DOI: 10.1111/tra.12389] [Citation(s) in RCA: 282] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Revised: 02/25/2016] [Accepted: 02/25/2016] [Indexed: 12/12/2022]
Abstract
Ari Helenius launched the field of enveloped virus fusion in endosomes with a seminal paper in the Journal of Cell Biology in 1980. In the intervening years, a great deal has been learned about the structures and mechanisms of viral membrane fusion proteins as well as about the endosomes in which different enveloped viruses fuse and the endosomal cues that trigger fusion. We now recognize three classes of viral membrane fusion proteins based on structural criteria and four mechanisms of fusion triggering. After reviewing general features of viral membrane fusion proteins and viral fusion in endosomes, we delve into three characterized mechanisms for viral fusion triggering in endosomes: by low pH, by receptor binding plus low pH and by receptor binding plus the action of a protease. We end with a discussion of viruses that may employ novel endosomal fusion‐triggering mechanisms. A key take‐home message is that enveloped viruses that enter cells by fusing in endosomes traverse the endocytic pathway until they reach an endosome that has all of the environmental conditions (pH, proteases, ions, intracellular receptors and lipid composition) to (if needed) prime and (in all cases) trigger the fusion protein and to support membrane fusion.
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Affiliation(s)
- Judith M White
- Department of Cell Biology, University of Virginia, Charlottesville, VA, USA
| | - Gary R Whittaker
- Department of Microbiology & Immunology, Cornell University, Ithaca, NY, USA
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Stone JA, Nicola AV, Baum LG, Aguilar HC. Multiple Novel Functions of Henipavirus O-glycans: The First O-glycan Functions Identified in the Paramyxovirus Family. PLoS Pathog 2016; 12:e1005445. [PMID: 26867212 PMCID: PMC4750917 DOI: 10.1371/journal.ppat.1005445] [Citation(s) in RCA: 18] [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: 08/05/2015] [Accepted: 01/19/2016] [Indexed: 01/13/2023] Open
Abstract
O-linked glycosylation is a ubiquitous protein modification in organisms belonging to several kingdoms. Both microbial and host protein glycans are used by many pathogens for host invasion and immune evasion, yet little is known about the roles of O-glycans in viral pathogenesis. Reportedly, there is no single function attributed to O-glycans for the significant paramyxovirus family. The paramyxovirus family includes many important pathogens, such as measles, mumps, parainfluenza, metapneumo- and the deadly Henipaviruses Nipah (NiV) and Hendra (HeV) viruses. Paramyxoviral cell entry requires the coordinated actions of two viral membrane glycoproteins: the attachment (HN/H/G) and fusion (F) glycoproteins. O-glycan sites in HeV G were recently identified, facilitating use of the attachment protein of this deadly paramyxovirus as a model to study O-glycan functions. We mutated the identified HeV G O-glycosylation sites and found mutants with altered cell-cell fusion, G conformation, G/F association, viral entry in a pseudotyped viral system, and, quite unexpectedly, pseudotyped viral F protein incorporation and processing phenotypes. These are all important functions of viral glycoproteins. These phenotypes were broadly conserved for equivalent NiV mutants. Thus our results identify multiple novel and pathologically important functions of paramyxoviral O-glycans, paving the way to study O-glycan functions in other paramyxoviruses and enveloped viruses.
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Affiliation(s)
- Jacquelyn A. Stone
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, United States of America
| | - Anthony V. Nicola
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, United States of America
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, United States of America
| | - Linda G. Baum
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, California, United States of America
| | - Hector C. Aguilar
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, United States of America
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington, United States of America
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47
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Markosyan RM, Miao C, Zheng YM, Melikyan GB, Liu SL, Cohen FS. Induction of Cell-Cell Fusion by Ebola Virus Glycoprotein: Low pH Is Not a Trigger. PLoS Pathog 2016; 12:e1005373. [PMID: 26730950 PMCID: PMC4711667 DOI: 10.1371/journal.ppat.1005373] [Citation(s) in RCA: 28] [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: 05/05/2015] [Accepted: 12/08/2015] [Indexed: 12/11/2022] Open
Abstract
Ebola virus (EBOV) is a highly pathogenic filovirus that causes hemorrhagic fever in humans and animals. Currently, how EBOV fuses its envelope membrane within an endosomal membrane to cause infection is poorly understood. We successfully measure cell-cell fusion mediated by the EBOV fusion protein, GP, assayed by the transfer of both cytoplasmic and membrane dyes. A small molecule fusion inhibitor, a neutralizing antibody, as well as mutations in EBOV GP known to reduce viral infection, all greatly reduce fusion. By monitoring redistribution of small aqueous dyes between cells and by electrical capacitance measurements, we discovered that EBOV GP-mediated fusion pores do not readily enlarge—a marked difference from the behavior of other viral fusion proteins. EBOV GP must be cleaved by late endosome-resident cathepsins B or L in order to become fusion-competent. Cleavage of cell surface-expressed GP appears to occur in endosomes, as evidenced by the fusion block imposed by cathepsin inhibitors, agents that raise endosomal pH, or an inhibitor of anterograde trafficking. Treating effector cells with a recombinant soluble cathepsin B or thermolysin, which cleaves GP into an active form, increases the extent of fusion, suggesting that a fraction of surface-expressed GP is not cleaved. Whereas the rate of fusion is increased by a brief exposure to acidic pH, fusion does occur at neutral pH. Importantly, the extent of fusion is independent of external pH in experiments in which cathepsin activity is blocked and EBOV GP is cleaved by thermolysin. These results imply that low pH promotes fusion through the well-known pH-dependent activity of cathepsins; fusion induced by cleaved EBOV GP is a process that is fundamentally independent of pH. The cell-cell fusion system has revealed some previously unappreciated features of EBOV entry, which could not be readily elucidated in the context of endosomal entry. The devastation and transmissibility of Ebola virus (EBOV) are well known. However, the manner in which EBOV enters host cells through endosomal membrane remains elusive. Here, we have developed a convenient experimental system to mimic EBOV fusion in endosomes: cells expressing the fusion protein of EBOV, GP, on their surface are fused to target cells. This system exhibits the known key properties of EBOV fusion. We show that the pH-dependence of EBOV fusion is caused by the pH-dependence of cathepsins, proteases known to cleave EBOV GP into a fusion-competent form. We demonstrate that the fusion activity of this cleaved form is independent of pH. We further show that the enlargement of the fusion pore created by EBOV GP is unusually slow in reaching sizes necessary to pass EBOV’s genome—this is atypical of virally created fusion pores. This cell-cell fusion system should provide a useful platform for developing drugs against EBOV infection.
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Affiliation(s)
- Ruben M. Markosyan
- Rush University Medical Center, Department of Molecular Biophysics and Physiology, Chicago, Illinois, United States of America
| | - Chunhui Miao
- University of Missouri School of Medicine, Bond Life Sciences Center, Department of Molecular Microbiology and Immunology, Columbia, Missouri, United States of America
| | - Yi-Min Zheng
- University of Missouri School of Medicine, Bond Life Sciences Center, Department of Molecular Microbiology and Immunology, Columbia, Missouri, United States of America
| | - Gregory B. Melikyan
- Emory University Medical School, Department of Pediatrics, Infectious Diseases, Atlanta, Georgia, United States of America
| | - Shan-Lu Liu
- University of Missouri School of Medicine, Bond Life Sciences Center, Department of Molecular Microbiology and Immunology, Columbia, Missouri, United States of America
- * E-mail: (SLL); (FSC)
| | - Fredric S. Cohen
- Rush University Medical Center, Department of Molecular Biophysics and Physiology, Chicago, Illinois, United States of America
- * E-mail: (SLL); (FSC)
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Xu K, Chan YP, Bradel-Tretheway B, Akyol-Ataman Z, Zhu Y, Dutta S, Yan L, Feng Y, Wang LF, Skiniotis G, Lee B, Zhou ZH, Broder CC, Aguilar HC, Nikolov DB. Crystal Structure of the Pre-fusion Nipah Virus Fusion Glycoprotein Reveals a Novel Hexamer-of-Trimers Assembly. PLoS Pathog 2015; 11:e1005322. [PMID: 26646856 PMCID: PMC4672880 DOI: 10.1371/journal.ppat.1005322] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 11/11/2015] [Indexed: 12/05/2022] Open
Abstract
Nipah virus (NiV) is a paramyxovirus that infects host cells through the coordinated efforts of two envelope glycoproteins. The G glycoprotein attaches to cell receptors, triggering the fusion (F) glycoprotein to execute membrane fusion. Here we report the first crystal structure of the pre-fusion form of the NiV-F glycoprotein ectodomain. Interestingly this structure also revealed a hexamer-of-trimers encircling a central axis. Electron tomography of Nipah virus-like particles supported the hexameric pre-fusion model, and biochemical analyses supported the hexamer-of-trimers F assembly in solution. Importantly, structure-assisted site-directed mutagenesis of the interfaces between F trimers highlighted the functional relevance of the hexameric assembly. Shown here, in both cell-cell fusion and virus-cell fusion systems, our results suggested that this hexamer-of-trimers assembly was important during fusion pore formation. We propose that this assembly would stabilize the pre-fusion F conformation prior to cell attachment and facilitate the coordinated transition to a post-fusion conformation of all six F trimers upon triggering of a single trimer. Together, our data reveal a novel and functional pre-fusion architecture of a paramyxoviral fusion glycoprotein.
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Affiliation(s)
- Kai Xu
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Yee-Peng Chan
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland, United States of America
| | - Birgit Bradel-Tretheway
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, United States of America
| | - Zeynep Akyol-Ataman
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, David Geffen School of Medicine, Los Angeles, California, United States of America
| | - Yongqun Zhu
- Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, Zhejiang, China
| | - Somnath Dutta
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Lianying Yan
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland, United States of America
| | - YanRu Feng
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland, United States of America
| | - Lin-Fa Wang
- CSIRO Animal, Food and Health Sciences, Australian Animal Health Laboratory, Geelong, Victoria, Australia
- Program in Emerging Infectious Diseases, Duke-NUS Graduate Medical School, Singapore, Singapore
| | - Georgios Skiniotis
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Benhur Lee
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Z. Hong Zhou
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, David Geffen School of Medicine, Los Angeles, California, United States of America
- California NanoSystems Institute, University of California, Los Angeles, David Geffen School of Medicine, Los Angeles, California, United States of America
| | - Christopher C. Broder
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland, United States of America
| | - Hector C. Aguilar
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, United States of America
| | - Dimitar B. Nikolov
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
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Abstract
UNLABELLED Human cathepsin W (CtsW) is a cysteine protease, which was identified in a genome-wide RNA interference (RNAi) screen to be required for influenza A virus (IAV) replication. In this study, we show that reducing the levels of expression of CtsW reduces viral titers for different subtypes of IAV, and we map the target step of CtsW requirement to viral entry. Using a set of small interfering RNAs (siRNAs) targeting CtsW, we demonstrate that knockdown of CtsW results in a decrease of IAV nucleoprotein accumulation in the nuclei of infected cells at 3 h postinfection. Assays specific for the individual stages of IAV entry further show that attachment, internalization, and early endosomal trafficking are not affected by CtsW knockdown. However, we detected impaired escape of viral particles from late endosomes in CtsW knockdown cells. Moreover, fusion analysis with a dual-labeled influenza virus revealed a significant reduction in fusion events, with no detectable impact on endosomal pH, suggesting that CtsW is required at the stage of viral fusion. The defect in IAV entry upon CtsW knockdown could be rescued by ectopic expression of wild-type CtsW but not by the expression of a catalytically inactive mutant of CtsW, suggesting that the proteolytic activity of CtsW is required for successful entry of IAV. Our results establish CtsW as an important host factor for entry of IAV into target cells and suggest that CtsW could be a promising target for the development of future antiviral drugs. IMPORTANCE Increasing levels of resistance of influenza viruses to available antiviral drugs have been observed. Development of novel treatment options is therefore of high priority. In parallel to the classical approach of targeting viral enzymes, a novel strategy is pursued: cell-dependent factors of the virus are identified with the aim of developing small-molecule inhibitors against a cellular target that the virus relies on. For influenza A virus, several genome-wide RNA interference (RNAi) screens revealed hundreds of potential cellular targets. However, we have only limited knowledge on how these factors support virus replication, which would be required for drug development. We have characterized cathepsin W, one of the candidate factors, and found that cathepsin W is required for escape of influenza virus from the late endosome. Importantly, this required the proteolytic activity of cathepsin W. We therefore suggest that cathepsin W could be a target for future host cell-directed antiviral therapies.
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Weis M, Maisner A. Nipah virus fusion protein: Importance of the cytoplasmic tail for endosomal trafficking and bioactivity. Eur J Cell Biol 2015; 94:316-22. [PMID: 26059400 PMCID: PMC7114669 DOI: 10.1016/j.ejcb.2015.05.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Nipah virus (NiV) is a highly pathogenic paramyxovirus which encodes two surface glycoproteins: the receptor-binding protein G and the fusion protein F. As for all paramyxoviruses, proteolytic activation of the NiV-F protein is an indispensable prerequisite for viral infectivity. Interestingly, proteolytic activation of NiV-F differs principally from other paramyxoviruses with respect to protease usage (cathepsins instead of trypsin- or furin-like proteases), and the subcellular localization where cleavage takes place (endosomes instead of Golgi or plasma membrane). To allow efficient F protein activation needed for productive virus replication and cell-to-cell fusion, the NiV-F cytoplasmic tail contains a classical tyrosine-based endocytosis signal (Y525RSL) that we have shown earlier to be needed for F uptake and proteolytic activation. In this report, we furthermore revealed that an intact endocytosis signal alone is not sufficient for full bioactivity. The very C-terminus of the cytoplasmic tail is needed in addition. Deletions of more than four residues did not affect F uptake or endosomal cleavage but downregulated the surface expression, likely by delaying the intracellular trafficking through endosomal-recycling compartments. Given that the NiV-F cytoplasmic tail is needed for timely and correct intracellular trafficking, endosomal cleavage and fusion activity, the influence of tail truncations on NiV-mediated cell-to-cell fusion and on pseudotyping lentiviral vectors is discussed.
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Affiliation(s)
- Michael Weis
- Institute of Virology, Philipps University of Marburg, Marburg, Germany
| | - Andrea Maisner
- Institute of Virology, Philipps University of Marburg, Marburg, Germany.
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