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Štěrbová P, Wang CH, Carillo KJD, Lou YC, Kato T, Namba K, Tzou DLM, Chang WH. Molecular Mechanism of pH-Induced Protrusion Configuration Switching in Piscine Betanodavirus Implies a Novel Antiviral Strategy. ACS Infect Dis 2024; 10:3304-3319. [PMID: 39087906 PMCID: PMC11406519 DOI: 10.1021/acsinfecdis.4c00407] [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] [Indexed: 08/02/2024]
Abstract
Many viruses contain surface spikes or protrusions that are essential for virus entry. These surface structures can thereby be targeted by antiviral drugs to treat viral infections. Nervous necrosis virus (NNV), a simple nonenveloped virus in the genus of betanodavirus, infects fish and damages aquaculture worldwide. NNV has 60 conspicuous surface protrusions, each comprising three protrusion domains (P-domain) of its capsid protein. NNV uses protrusions to bind to common receptors of sialic acids on the host cell surface to initiate its entry via the endocytic pathway. However, structural alterations of NNV in response to acidic conditions encountered during this pathway remain unknown, while detailed interactions of protrusions with receptors are unclear. Here, we used cryo-EM to discover that Grouper NNV protrusions undergo low-pH-induced compaction and resting. NMR and molecular dynamics (MD) simulations were employed to probe the atomic details. A solution structure of the P-domain at pH 7.0 revealed a long flexible loop (amino acids 311-330) and a pocket outlined by this loop. Molecular docking analysis showed that the N-terminal moiety of sialic acid inserted into this pocket to interact with conserved residues inside. MD simulations demonstrated that part of this loop converted to a β-strand under acidic conditions, allowing for P-domain trimerization and compaction. Additionally, a low-pH-favored conformation is attained for the linker connecting the P-domain to the NNV shell, conferring resting protrusions. Our findings uncover novel pH-dependent conformational switching mechanisms underlying NNV protrusion dynamics potentially utilized for facilitating NNV entry, providing new structural insights into complex NNV-host interactions with the identification of putative druggable hotspots on the protrusion.
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Affiliation(s)
- Petra Štěrbová
- Chemical Biology and Molecular Biophysics Program, Taiwan International Graduate Program, Academia Sinica, Taipei 11529, Taiwan
- College of Life Science, National Tsing Hua University, Hsinchu 30044, Taiwan
- Institute of Chemistry, Academia Sinica, Taipei 11529, Taiwan
| | | | | | - Yuan-Chao Lou
- Biomedical Translation Research Center, Academia Sinica, Taipei 11529, Taiwan
| | - Takayuki Kato
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Keiichi Namba
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Der-Lii M Tzou
- Institute of Chemistry, Academia Sinica, Taipei 11529, Taiwan
| | - Wei-Hau Chang
- Chemical Biology and Molecular Biophysics Program, Taiwan International Graduate Program, Academia Sinica, Taipei 11529, Taiwan
- Institute of Chemistry, Academia Sinica, Taipei 11529, Taiwan
- Genomics Research Center, Academia Sinica, Taipei 11529, Taiwan
- Institute of Physics, Academia Sinica, Taipei 11529, Taiwan
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2
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Quirino A, Marascio N, Branda F, Ciccozzi A, Romano C, Locci C, Azzena I, Pascale N, Pavia G, Matera G, Casu M, Sanna D, Giovanetti M, Ceccarelli G, Alaimo di Loro P, Ciccozzi M, Scarpa F, Maruotti A. Viral Hepatitis: Host Immune Interaction, Pathogenesis and New Therapeutic Strategies. Pathogens 2024; 13:766. [PMID: 39338957 PMCID: PMC11435051 DOI: 10.3390/pathogens13090766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2024] [Revised: 08/30/2024] [Accepted: 09/02/2024] [Indexed: 09/30/2024] Open
Abstract
Viral hepatitis is a major cause of liver illness worldwide. Despite advances in the understanding of these infections, the pathogenesis of hepatitis remains a complex process driven by intricate interactions between hepatitis viruses and host cells at the molecular level. This paper will examine in detail the dynamics of these host-pathogen interactions, highlighting the key mechanisms that regulate virus entry into the hepatocyte, their replication, evasion of immune responses, and induction of hepatocellular damage. The unique strategies employed by different hepatitis viruses, such as hepatitis B, C, D, and E viruses, to exploit metabolic and cell signaling pathways to their advantage will be discussed. At the same time, the innate and adaptive immune responses put in place by the host to counter viral infection will be analyzed. Special attention will be paid to genetic, epigenetic, and environmental factors that modulate individual susceptibility to different forms of viral hepatitis. In addition, this work will highlight the latest findings on the mechanisms of viral persistence leading to the chronic hepatitis state and the potential implications for the development of new therapeutic strategies. Fully understanding the complex host-pathogen interactions in viral hepatitis is crucial to identifying new therapeutic targets, developing more effective approaches for treatment, and shedding light on the mechanisms underlying progression to more advanced stages of liver damage.
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Affiliation(s)
- Angela Quirino
- Unit of Clinical Microbiology, Department of Health Sciences, “Magna Græcia” University of Catanzaro “Renato Dulbecco” Teaching Hospital, 88100 Catanzaro, Italy; (A.Q.); (N.M.); (G.P.); (G.M.)
| | - Nadia Marascio
- Unit of Clinical Microbiology, Department of Health Sciences, “Magna Græcia” University of Catanzaro “Renato Dulbecco” Teaching Hospital, 88100 Catanzaro, Italy; (A.Q.); (N.M.); (G.P.); (G.M.)
| | - Francesco Branda
- Unit of Medical Statistics and Molecular Epidemiology, Università Campus Bio-Medico di Roma, 00128 Rome, Italy; (C.R.); (M.C.)
| | - Alessandra Ciccozzi
- Department of Biomedical Sciences, University of Sassari, 07100 Sassari, Italy; (A.C.); (C.L.); (D.S.); (F.S.)
| | - Chiara Romano
- Unit of Medical Statistics and Molecular Epidemiology, Università Campus Bio-Medico di Roma, 00128 Rome, Italy; (C.R.); (M.C.)
| | - Chiara Locci
- Department of Biomedical Sciences, University of Sassari, 07100 Sassari, Italy; (A.C.); (C.L.); (D.S.); (F.S.)
- Department of Veterinary Medicine, University of Sassari, 07100 Sassari, Italy; (I.A.); (N.P.); (M.C.)
| | - Ilenia Azzena
- Department of Veterinary Medicine, University of Sassari, 07100 Sassari, Italy; (I.A.); (N.P.); (M.C.)
| | - Noemi Pascale
- Department of Veterinary Medicine, University of Sassari, 07100 Sassari, Italy; (I.A.); (N.P.); (M.C.)
- Department of Chemical Physical Mathematical and Natural Sciences, University of Sassari, 07100 Sassari, Italy
| | - Grazia Pavia
- Unit of Clinical Microbiology, Department of Health Sciences, “Magna Græcia” University of Catanzaro “Renato Dulbecco” Teaching Hospital, 88100 Catanzaro, Italy; (A.Q.); (N.M.); (G.P.); (G.M.)
| | - Giovanni Matera
- Unit of Clinical Microbiology, Department of Health Sciences, “Magna Græcia” University of Catanzaro “Renato Dulbecco” Teaching Hospital, 88100 Catanzaro, Italy; (A.Q.); (N.M.); (G.P.); (G.M.)
| | - Marco Casu
- Department of Veterinary Medicine, University of Sassari, 07100 Sassari, Italy; (I.A.); (N.P.); (M.C.)
| | - Daria Sanna
- Department of Biomedical Sciences, University of Sassari, 07100 Sassari, Italy; (A.C.); (C.L.); (D.S.); (F.S.)
| | - Marta Giovanetti
- Department of Sciences and Technologies for Sustainable Development and One Health, Università Campus Bio-Medico di Roma, 00128 Rome, Italy;
- Instituto René Rachou, Fundação Oswaldo Cruz, Belo Horizonte 30190-002, MG, Brazil
- Climate Amplified Diseases and Epidemics (CLIMADE), Brasilia 70070-130, GO, Brazil
| | - Giancarlo Ceccarelli
- Department of Public Health and Infectious Diseases, University Hospital Policlinico Umberto I, Sapienza University of Rome, 00161 Rome, Italy;
| | | | - Massimo Ciccozzi
- Unit of Medical Statistics and Molecular Epidemiology, Università Campus Bio-Medico di Roma, 00128 Rome, Italy; (C.R.); (M.C.)
| | - Fabio Scarpa
- Department of Biomedical Sciences, University of Sassari, 07100 Sassari, Italy; (A.C.); (C.L.); (D.S.); (F.S.)
| | - Antonello Maruotti
- Department GEPLI, Libera Università Maria Ss Assunta, 00193 Rome, Italy;
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3
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Sun W, Wang M, Shi Z, Wang P, Wang J, Du B, Wang S, Sun Z, Liu Z, Wei L, Yang D, He X, Wang J. VP2 mediates the release of the feline calicivirus RNA genome by puncturing the endosome membrane of infected cells. J Virol 2024; 98:e0035024. [PMID: 38591900 PMCID: PMC11092339 DOI: 10.1128/jvi.00350-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Accepted: 03/19/2024] [Indexed: 04/10/2024] Open
Abstract
Feline calicivirus (FCV) is one of the few members of the Caliciviridae family that grows well in cell lines and, therefore, serves as a surrogate to study the biology of other viruses in the family. Conley et al. (14) demonstrated that upon the receptor engagement to the capsid, FCV VP2 forms a portal-like assembly, which might provide a channel for RNA release. However, the process of calicivirus RNA release is not yet fully understood. Our findings suggest that the separation of the FCV capsid from its genome RNA (gRNA) occurs rapidly in the early endosomes of infected cells. Using a liposome model decorated with the FCV cell receptor fJAM-A, we demonstrate that FCV releases its gRNA into the liposomes by penetrating membranes under low pH conditions. Furthermore, we found that VP2, which is rich in hydrophobic residues at its N-terminus, functions as the pore-forming protein. When we substituted the VP2 N-terminal hydrophobic residues, the gRNA release efficacy of the FCV mutants decreased. In conclusion, our results suggest that in the acidic environment of early endosomes, FCV VP2 functions as the pore-forming protein to mediate gRNA release into the cytoplasm of infected cells. This provides insight into the mechanism of calicivirus genome release.IMPORTANCEResearch on the biology and pathogenicity of certain caliciviruses, such as Norovirus and Sapovirus, is hindered by the lack of easy-to-use cell culture system. Feline calicivirus (FCV), which grows effectively in cell lines, is used as a substitute. At present, there is limited understanding of the genome release mechanism in caliciviruses. Our findings suggest that FCV uses VP2 to pierce the endosome membrane for genome release and provide new insights into the calicivirus gRNA release mechanism.
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Affiliation(s)
- Weiyao Sun
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Ming Wang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Zhibin Shi
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Pengfei Wang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Jinhui Wang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Bingchen Du
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Shida Wang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Zhenzhao Sun
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Zaisi Liu
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Lili Wei
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Decheng Yang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Xijun He
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
| | - Jingfei Wang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China
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Cárdenas M, Michelson S, Galleguillos C, Vásquez-Martínez Y, Cortez-San Martin M. Modulation of infectious Salmon Anaemia virus infection by clathrin-mediated endocytosis and macropinocytosis inhibitors. Res Vet Sci 2024; 171:105223. [PMID: 38520841 DOI: 10.1016/j.rvsc.2024.105223] [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: 08/24/2023] [Revised: 12/19/2023] [Accepted: 03/09/2024] [Indexed: 03/25/2024]
Abstract
Infectious salmon anaemia virus (ISAV) is a pathogen that causes disease and large mortality in farm-raised Salmo salar L., being considered as a major problem in the salmon industry. However, despite its relevance, there are still numerous knowledge gaps on virus entry and early stages of infection. Previous studies suggested that virus entry into cells occurs via endocytosis, with no description of specific mechanisms. However, it remains unknown if the endocytosis induced by ISAV is a clathrin-dependent or clathrin-independent process. This study aimed to identify cellular mechanisms allowing ISAV entry into Atlantic Salmon head kidney (ASK) cells. Our results showed that ISAV can be found in coated pits and membrane ruffles, the latter being induced by a rearrangement of actin filaments promoted by ISAV infection. Additionally, it was determined that ISAV stimulate the uptake of extracellular fluid in a multiplicity of infection (MOI)-dependent manner. When the clathrin-mediated endocytic pathway was pharmacologically inhibited, ISAV infection was significantly reduced but not entirely inhibited. Similarly, when the Na+/H+ exchanger (NHE), a key component of macropinocytosis, was inhibited, ISAV infection was negatively affected. Our results suggest that ISAV enters cells via both clathrin-mediated endocytosis and most likely macropinocytosis.
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Affiliation(s)
- Matías Cárdenas
- Laboratory of Molecular Virology and Pathogen Control, Department of Biology, Faculty of Chemistry and Biology, University of Santiago de Chile, Santiago, Chile; Poultry Diagnostic and Research Center, Department of Population Health, University of Georgia, Athens, GA 30602, USA
| | - Sofía Michelson
- Laboratory of Molecular Virology and Pathogen Control, Department of Biology, Faculty of Chemistry and Biology, University of Santiago de Chile, Santiago, Chile
| | - Claudia Galleguillos
- Laboratory of Molecular Virology and Pathogen Control, Department of Biology, Faculty of Chemistry and Biology, University of Santiago de Chile, Santiago, Chile
| | - Yesseny Vásquez-Martínez
- Laboratory of Molecular Virology and Pathogen Control, Department of Biology, Faculty of Chemistry and Biology, University of Santiago de Chile, Santiago, Chile; Medicine School, Faculty of Medical Sciences, University of Santiago de Chile, Santiago, Chile
| | - Marcelo Cortez-San Martin
- Laboratory of Molecular Virology and Pathogen Control, Department of Biology, Faculty of Chemistry and Biology, University of Santiago de Chile, Santiago, Chile.
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5
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Styles CT, Zhou J, Flight KE, Brown JC, Lewis C, Wang X, Vanden Oever M, Peacock TP, Wang Z, Millns R, O'Neill JS, Borodavka A, Grove J, Barclay WS, Tregoning JS, Edgar RS. Propylene glycol inactivates respiratory viruses and prevents airborne transmission. EMBO Mol Med 2023; 15:e17932. [PMID: 37970627 PMCID: PMC10701621 DOI: 10.15252/emmm.202317932] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 10/16/2023] [Accepted: 10/17/2023] [Indexed: 11/17/2023] Open
Abstract
Viruses are vulnerable as they transmit between hosts, and we aimed to exploit this critical window. We found that the ubiquitous, safe, inexpensive and biodegradable small molecule propylene glycol (PG) has robust virucidal activity. Propylene glycol rapidly inactivates a broad range of viruses including influenza A, SARS-CoV-2 and rotavirus and reduces disease burden in mice when administered intranasally at concentrations commonly found in nasal sprays. Most critically, vaporised PG efficiently abolishes influenza A virus and SARS-CoV-2 infectivity within airborne droplets, potently preventing infection at levels well below those tolerated by mammals. We present PG vapour as a first-in-class non-toxic airborne virucide that can prevent transmission of existing and emergent viral pathogens, with clear and immediate implications for public health.
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Affiliation(s)
| | - Jie Zhou
- Department of Infectious DiseaseImperial College LondonLondonUK
| | - Katie E Flight
- Department of Infectious DiseaseImperial College LondonLondonUK
- Present address:
University College LondonLondonUK
| | | | - Charlotte Lewis
- MRC‐University of Glasgow Centre for Virus ResearchGlasgowUK
| | - Xinyu Wang
- Department of BiochemistryUniversity of CambridgeCambridgeUK
| | - Michael Vanden Oever
- Department of Infectious DiseaseImperial College LondonLondonUK
- Present address:
Life Edit TherapeuticsMorrisvilleNCUSA
| | | | - Ziyin Wang
- Department of Infectious DiseaseImperial College LondonLondonUK
| | - Rosie Millns
- Department of Infectious DiseaseImperial College LondonLondonUK
| | | | | | - Joe Grove
- MRC‐University of Glasgow Centre for Virus ResearchGlasgowUK
| | - Wendy S Barclay
- Department of Infectious DiseaseImperial College LondonLondonUK
| | | | - Rachel S Edgar
- Department of Infectious DiseaseImperial College LondonLondonUK
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6
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Odongo L, Habtegebrael BH, Kiessling V, White JM, Tamm LK. A novel in vitro system of supported planar endosomal membranes (SPEMs) reveals an enhancing role for cathepsin B in the final stage of Ebola virus fusion and entry. Microbiol Spectr 2023; 11:e0190823. [PMID: 37728342 PMCID: PMC10581071 DOI: 10.1128/spectrum.01908-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 07/17/2023] [Indexed: 09/21/2023] Open
Abstract
Ebola virus (EBOV) causes a hemorrhagic fever with fatality rates up to 90%. The EBOV entry process is complex and incompletely understood. Following attachment to host cells, EBOV is trafficked to late endosomes/lysosomes where its glycoprotein (GP) is processed to a 19-kDa form, which binds to the EBOV intracellular receptor Niemann-Pick type C1. We previously showed that the cathepsin protease inhibitor, E-64d, blocks infection by pseudovirus particles bearing 19-kDa GP, suggesting that further cathepsin action is needed to trigger fusion. This, however, has not been demonstrated directly. Since 19-kDa Ebola GP fusion occurs in late endosomes, we devised a system in which enriched late endosomes are used to prepare supported planar endosomal membranes (SPEMs), and fusion of fluorescent (pseudo)virus particles is monitored by total internal reflection fluorescence microscopy. We validated the system by demonstrating the pH dependencies of influenza virus hemagglutinin (HA)-mediated and Lassa virus (LASV) GP-mediated fusion. Using SPEMs, we showed that fusion mediated by 19-kDa Ebola GP is dependent on low pH, enhanced by Ca2+, and augmented by the addition of cathepsins. Subsequently, we found that E-64d inhibits full fusion, but not lipid mixing, mediated by 19-kDa GP, which we corroborated with the reversible cathepsin inhibitor VBY-825. Hence, we provide both gain- and loss-of-function evidence that further cathepsin action enhances the fusion activity of 19-kDa Ebola GP. In addition to providing new insights into how Ebola GP mediates fusion, the approach we developed employing SPEMs can now be broadly used for studies of virus and toxin entry through endosomes. IMPORTANCE Ebola virus is the causative agent of Ebola virus disease, which is severe and frequently lethal. EBOV gains entry into cells via late endosomes/lysosomes. The events immediately preceding fusion of the viral and endosomal membranes are incompletely understood. In this study, we report a novel in vitro system for studying virus fusion with endosomal membranes. We validated the system by demonstrating the low pH dependencies of influenza and Lassa virus fusion. Moreover, we show that further cathepsin B action enhances the fusion activity of the primed Ebola virus glycoprotein. Finally, this model endosomal membrane system should be useful in studying the mechanisms of bilayer breaching by other enveloped viruses, by non-enveloped viruses, and by acid-activated bacterial toxins.
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Affiliation(s)
- Laura Odongo
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, Virginia, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
| | - Betelihem H. Habtegebrael
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, Virginia, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
| | - Volker Kiessling
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, Virginia, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
| | - Judith M. White
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, Virginia, USA
- Department of Cell Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Lukas K. Tamm
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, Virginia, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
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7
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Das A, Rivera-Serrano EE, Yin X, Walker CM, Feng Z, Lemon SM. Cell entry and release of quasi-enveloped human hepatitis viruses. Nat Rev Microbiol 2023; 21:573-589. [PMID: 37185947 PMCID: PMC10127183 DOI: 10.1038/s41579-023-00889-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/22/2023] [Indexed: 05/17/2023]
Abstract
Infectious hepatitis type A and type E are caused by phylogenetically distinct single-stranded, positive-sense RNA viruses that were once considered to be non-enveloped. However, studies show that both are released nonlytically from hepatocytes as 'quasi-enveloped' virions cloaked in host membranes. These virion types predominate in the blood of infected individuals and mediate virus spread within the liver. They lack virally encoded proteins on their surface and are resistant to neutralizing anti-capsid antibodies induced by infection, yet they efficiently enter cells and initiate new rounds of virus replication. In this Review, we discuss the mechanisms by which specific peptide sequences in the capsids of these quasi-enveloped virions mediate their endosomal sorting complexes required for transport (ESCRT)-dependent release from hepatocytes through multivesicular endosomes, what is known about how they enter cells, and the impact of capsid quasi-envelopment on host immunity and pathogenesis.
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Affiliation(s)
- Anshuman Das
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Lentigen Technology, Inc., Gaithersburg, MD, USA
| | - Efraín E Rivera-Serrano
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Biology, Elon University, Elon, NC, USA
| | - Xin Yin
- Center for Vaccines and Immunity, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin, China
| | - Christopher M Walker
- Center for Vaccines and Immunity, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
- Department of Paediatrics, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Zongdi Feng
- Center for Vaccines and Immunity, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA.
- Department of Paediatrics, The Ohio State University College of Medicine, Columbus, OH, USA.
| | - Stanley M Lemon
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Department of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Department of Microbiology & Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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8
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Ykema M, Ye K, Xun M, Harper J, Betancourt-Solis MA, Arias CF, McNew JA, Tao YJ. Human astrovirus capsid protein releases a membrane lytic peptide upon trypsin maturation. J Virol 2023; 97:e0080223. [PMID: 37504573 PMCID: PMC10506485 DOI: 10.1128/jvi.00802-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 06/13/2023] [Indexed: 07/29/2023] Open
Abstract
The human astrovirus (HAstV) is a non-enveloped, single-stranded RNA virus that is a common cause of gastroenteritis. Most non-enveloped viruses use membrane disruption to deliver the viral genome into a host cell after virus uptake. The virus-host factors that allow for HAstV cell entry are currently unknown but thought to be associated with the host-protease-mediated viral maturation. Using in vitro liposome disruption analysis, we identified a trypsin-dependent lipid disruption activity in the capsid protein of HAstV serotype 8. This function was further localized to the P1 domain of the viral capsid core, which was both necessary and sufficient for membrane disruption. Site-directed mutagenesis identified a cluster of four trypsin cleavage sites necessary to retain the lipid disruption activity, which is likely attributed to a short stretch of sequence ending at arginine 313 based on mass spectrometry of liposome-associated peptides. The membrane disruption activity was conserved across several other HAstVs, including the emerging VA2 strain, and effective against a wide range of lipid identities. This work provides key functional insight into the protease maturation process essential to HAstV infectivity and presents a method to investigate membrane penetration by non-enveloped viruses in vitro. IMPORTANCE Human astroviruses (HAstVs) are an understudied family of viruses that cause mild gastroenteritis but have recent cases associated with a more severe neural pathogenesis. Many important elements of the HAstV life cycle are not well understood, and further elucidating them can help understand the various forms of HAstV pathogenesis. In this study, we utilized an in vitro liposome-based assay to describe and characterize a previously unreported lipid disruption activity. This activity is dependent on the protease cleavage of key sites in HAstV capsid core and can be controlled by site-directed mutagenesis. Our group observed this activity in multiple strains of HAstV and in multiple lipid conditions, indicating this may be a conserved activity across the AstV family. The discovery of this function provides insight into HAstV cellular entry, pathogenesis, and a possible target for future therapeutics.
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Affiliation(s)
- Matthew Ykema
- Department of BioSciences, Rice University, Houston, Texas, USA
| | - Kai Ye
- Department of BioSciences, Rice University, Houston, Texas, USA
| | - Meng Xun
- Department of BioSciences, Rice University, Houston, Texas, USA
| | - Justin Harper
- Department of BioSciences, Rice University, Houston, Texas, USA
| | | | - Carlos F. Arias
- Departamento de Genética del Desarrollo y Fisiología Molecular, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | - James A. McNew
- Department of BioSciences, Rice University, Houston, Texas, USA
| | - Yizhi Jane Tao
- Department of BioSciences, Rice University, Houston, Texas, USA
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9
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Pletan M, Liu X, Cha G, Chen YJ, Knupp J, Tsai B. The atlastin ER morphogenic proteins promote formation of a membrane penetration site during non-enveloped virus entry. J Virol 2023; 97:e0075623. [PMID: 37578227 PMCID: PMC10506488 DOI: 10.1128/jvi.00756-23] [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: 05/22/2023] [Accepted: 06/28/2023] [Indexed: 08/15/2023] Open
Abstract
During entry, non-enveloped viruses penetrate a host membrane to cause infection, although how this is accomplished remains enigmatic. Polyomaviruses (PyVs) are non-enveloped DNA viruses that penetrate the endoplasmic reticulum (ER) membrane to reach the cytosol en route to the nucleus for infection. To penetrate the ER membrane, the prototype PyV simian virus 40 (SV40) induces formation of ER-escape sites, called foci, composed of repeating units of multi-tubular ER junctions where the virus is thought to exit. How SV40 triggers formation of the ER-foci harboring these multi-tubular ER junctions is unclear. Here, we show that the ER morphogenic atlastin 2 (ATL2) and ATL3 membrane proteins play critical roles in SV40 infection. Mechanistically, ATL3 mobilizes to the ER-foci where it deploys its GTPase-dependent membrane fusion activity to promote formation of multi-tubular ER junctions within the ER-foci. ATL3 also engages an SV40-containing membrane penetration complex. By contrast, ATL2 does not reorganize to the ER-foci. Instead, it supports the reticular ER morphology critical for the integrity of the ATL3-dependent membrane complex. Our findings illuminate how two host factors play distinct roles in the formation of an essential membrane penetration site for a non-enveloped virus. IMPORTANCE Membrane penetration by non-enveloped viruses, a critical infection step, remains enigmatic. The non-enveloped PyV simian virus 40 (SV40) penetrates the endoplasmic reticulum (ER) membrane to reach the cytosol en route for infection. During ER-to-cytosol membrane penetration, SV40 triggers formation of ER-associated structures (called ER-foci) that function as the membrane penetration sites. Here, we discover a role of the ATL ER membrane proteins-known to shape the ER morphology-during SV40-induced ER-foci formation. These findings illuminate how a non-enveloped virus hijacks host components to construct a membrane penetration structure.
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Affiliation(s)
- Madison Pletan
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Xiaofang Liu
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Grace Cha
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Yu-Jie Chen
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Jeffrey Knupp
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Billy Tsai
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, Michigan, USA
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10
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Winter SL, Chlanda P. The Art of Viral Membrane Fusion and Penetration. Subcell Biochem 2023; 106:113-152. [PMID: 38159225 DOI: 10.1007/978-3-031-40086-5_4] [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] [Indexed: 01/03/2024]
Abstract
As obligate pathogens, viruses have developed diverse mechanisms to deliver their genome across host cell membranes to sites of virus replication. While enveloped viruses utilize viral fusion proteins to accomplish fusion of their envelope with the cellular membrane, non-enveloped viruses rely on machinery that causes local membrane ruptures and creates an opening through which the capsid or viral genome is released. Both membrane fusion and membrane penetration take place at the plasma membrane or in intracellular compartments, often involving the engagement of the cellular machinery and antagonism of host restriction factors. Enveloped and non-enveloped viruses have evolved intricate mechanisms to enable virus uncoating and modulation of membrane fusion in a spatiotemporally controlled manner. This chapter summarizes and discusses the current state of understanding of the mechanisms of viral membrane fusion and penetration. The focus is on the role of lipids, viral scaffold uncoating, viral membrane fusion inhibitors, and host restriction factors as physicochemical modulators. In addition, recent advances in visualizing and detecting viral membrane fusion and penetration using cryo-electron microscopy methods are presented.
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Affiliation(s)
- Sophie L Winter
- Schaller Research Group, Department of Infectious Diseases, Virology, Heidelberg University Hospital, Heidelberg, Germany
| | - Petr Chlanda
- Schaller Research Group, Department of Infectious Diseases, Virology, Heidelberg University Hospital, Heidelberg, Germany.
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11
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Non-enveloped virus membrane penetration: New advances leading to new insights. PLoS Pathog 2022; 18:e1010948. [PMID: 36480535 PMCID: PMC9731489 DOI: 10.1371/journal.ppat.1010948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Host cell membranes pose a particular challenge for non-enveloped viruses. Whereas enveloped viruses enter cells by fusing their lipid envelopes with the cellular membrane, non-enveloped viruses generally must (1) enter cells via endocytosis, then (2) penetrate the cellular endomembrane to reach the cytosol. Only then can the viruses begin to replicate (or transit to the nucleus to replicate). Although membrane penetration of non-enveloped viruses is a crucial entry step, many of the precise molecular details of this process remain unclear. Recent findings have begun to untangle the various mechanisms by which non-enveloped viral proteins disrupt and penetrate cellular endomembranes. Specifically, high-resolution microscopy studies have revealed precise conformational changes in viral proteins that enable penetration, while biochemical studies have identified key host proteins that promote viral penetration and transport. This brief article summarizes new discoveries in the membrane penetration process for three of the most intensely studied families of non-enveloped viruses: reoviruses, papillomaviruses, and polyomaviruses.
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12
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Guo Y, Gao Y, Hu Y, Zhao Y, Jiang D, Wang Y, Zhang Y, Gan H, Xie C, Liu Z, Zhong B, Zhang Z, Yao J. The Transient Receptor Potential Vanilloid 2 (TRPV2) Channel Facilitates Virus Infection Through the Ca 2+ -LRMDA Axis in Myeloid Cells. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2202857. [PMID: 36261399 PMCID: PMC9731701 DOI: 10.1002/advs.202202857] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Revised: 09/13/2022] [Indexed: 06/16/2023]
Abstract
The transient receptor potential vanilloid 2 (TRPV2) channel is a nonselective cation channel that has been implicated in multiple sensory processes in the nervous system. Here, it is shown that TRPV2 in myeloid cells facilitates virus penetration by promoting the tension and mobility of cell membrane through the Ca2+ -LRMDA axis. Knockout of TRPV2 in myeloid cells or inhibition of TRPV2 channel activity suppresses viral infection and protects mice from herpes simplex virus 1 (HSV-1) and vesicular stomatitis virus (VSV) infection. Reconstitution of TRPV2 but not the Ca2+ -impermeable mutant TRPV2E572Q into LyZ2-Cre;Trpv2fl/fl bone marrow-derived dendritic cells (BMDCs) restores viral infection. Mechanistically, knockout of TRPV2 in myeloid cells inhibits the tension and mobility of cell membrane and the penetration of viruses, which is restored by reconstitution of TRPV2 but not TRPV2E572Q . In addition, knockout of TRPV2 leads to downregulation of Lrmda in BMDCs and BMDMs, and knockdown of Lrmda significantly downregulates the mobility and tension of cell membrane and inhibits viral infections in Trpv2fl/fl but not LyZ2-Cre;Trpv2fl/fl BMDCs. Consistently, complement of LRMDA into LyZ2-Cre;Trpv2fl/fl BMDCs partially restores the tension and mobility of cell membrane and promotes viral penetration and infection. These findings characterize a previously unknown function of myeloid TRPV2 in facilitating viral infection though the Ca2+ -LRMDA axis.
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Affiliation(s)
- Yu‐Yao Guo
- Department of Gastrointestinal SurgeryCollege of Life SciencesZhongnan Hospital of Wuhan UniversityWuhan UniversityWuhan430071China
- Department of ImmunologyMedical Research Institute and Frontier Science Center for Immunology and MetabolismWuhan UniversityWuhan430071China
- Wuhan Research Center for Infectious Diseases and CancerChinese Academy of Medical SciencesWuhan430071China
- State Key Laboratory of VirologyHubei Key Laboratory of Cell HomeostasisCollege of Life SciencesFrontier Science Center for Immunology and MetabolismWuhan UniversityWuhan430072China
| | - Yue Gao
- Department of Gastrointestinal SurgeryCollege of Life SciencesZhongnan Hospital of Wuhan UniversityWuhan UniversityWuhan430071China
- State Key Laboratory of VirologyHubei Key Laboratory of Cell HomeostasisCollege of Life SciencesFrontier Science Center for Immunology and MetabolismWuhan UniversityWuhan430072China
| | - Yu‐Ru Hu
- The Institute for Advanced StudiesWuhan UniversityWuhan430072China
| | - Yuhan Zhao
- State Key Laboratory of VirologyHubei Key Laboratory of Cell HomeostasisCollege of Life SciencesFrontier Science Center for Immunology and MetabolismWuhan UniversityWuhan430072China
| | - Dexiang Jiang
- State Key Laboratory of VirologyHubei Key Laboratory of Cell HomeostasisCollege of Life SciencesFrontier Science Center for Immunology and MetabolismWuhan UniversityWuhan430072China
| | - Yulin Wang
- State Key Laboratory of VirologyHubei Key Laboratory of Cell HomeostasisCollege of Life SciencesFrontier Science Center for Immunology and MetabolismWuhan UniversityWuhan430072China
| | - Youjing Zhang
- State Key Laboratory of VirologyHubei Key Laboratory of Cell HomeostasisCollege of Life SciencesFrontier Science Center for Immunology and MetabolismWuhan UniversityWuhan430072China
| | - Hu Gan
- Department of Gastrointestinal SurgeryCollege of Life SciencesZhongnan Hospital of Wuhan UniversityWuhan UniversityWuhan430071China
- Department of ImmunologyMedical Research Institute and Frontier Science Center for Immunology and MetabolismWuhan UniversityWuhan430071China
- Wuhan Research Center for Infectious Diseases and CancerChinese Academy of Medical SciencesWuhan430071China
| | - Chang Xie
- State Key Laboratory of VirologyHubei Key Laboratory of Cell HomeostasisCollege of Life SciencesFrontier Science Center for Immunology and MetabolismWuhan UniversityWuhan430072China
| | - Zheng Liu
- The Institute for Advanced StudiesWuhan UniversityWuhan430072China
| | - Bo Zhong
- Department of Gastrointestinal SurgeryCollege of Life SciencesZhongnan Hospital of Wuhan UniversityWuhan UniversityWuhan430071China
- Department of ImmunologyMedical Research Institute and Frontier Science Center for Immunology and MetabolismWuhan UniversityWuhan430071China
- Wuhan Research Center for Infectious Diseases and CancerChinese Academy of Medical SciencesWuhan430071China
| | - Zhi‐Dong Zhang
- Department of Gastrointestinal SurgeryCollege of Life SciencesZhongnan Hospital of Wuhan UniversityWuhan UniversityWuhan430071China
- Department of ImmunologyMedical Research Institute and Frontier Science Center for Immunology and MetabolismWuhan UniversityWuhan430071China
- Wuhan Research Center for Infectious Diseases and CancerChinese Academy of Medical SciencesWuhan430071China
| | - Jing Yao
- Department of Gastrointestinal SurgeryCollege of Life SciencesZhongnan Hospital of Wuhan UniversityWuhan UniversityWuhan430071China
- Department of ImmunologyMedical Research Institute and Frontier Science Center for Immunology and MetabolismWuhan UniversityWuhan430071China
- State Key Laboratory of VirologyHubei Key Laboratory of Cell HomeostasisCollege of Life SciencesFrontier Science Center for Immunology and MetabolismWuhan UniversityWuhan430072China
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13
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Endocytosis triggers V-ATPase-SYK-mediated priming of cGAS activation and innate immune response. Proc Natl Acad Sci U S A 2022; 119:e2207280119. [PMID: 36252040 PMCID: PMC9618142 DOI: 10.1073/pnas.2207280119] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The current view of nucleic acid-mediated innate immunity is that binding of intracellular sensors to nucleic acids is sufficient for their activation. Here, we report that endocytosis of virus or foreign DNA initiates a priming signal for the DNA sensor cyclic GMP-AMP synthase (cGAS)-mediated innate immune response. Mechanistically, viral infection or foreign DNA transfection triggers recruitment of the spleen tyrosine kinase (SYK) and cGAS to the endosomal vacuolar H+ pump (V-ATPase), where SYK is activated and then phosphorylates human cGASY214/215 (mouse cGasY200/201) to prime its activation. Upon binding to DNA, the primed cGAS initiates robust cGAMP production and mediator of IRF3 activation/stimulator of interferon genes-dependent innate immune response. Consistently, blocking the V-ATPase-SYK axis impairs DNA virus- and transfected DNA-induced cGAMP production and expression of antiviral genes. Our findings reveal that V-ATPase-SYK-mediated tyrosine phosphorylation of cGAS following endocytosis of virus or other cargos serves as a priming signal for cGAS activation and innate immune response.
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14
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Protein Myristoylation Plays a Role in the Nuclear Entry of the Parvovirus Minute Virus of Mice. J Virol 2022; 96:e0111822. [PMID: 35950857 PMCID: PMC9472656 DOI: 10.1128/jvi.01118-22] [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: 11/20/2022] Open
Abstract
Being nonpathogenic to humans, rodent parvoviruses (PVs) are naturally oncolytic viruses with great potential as anti-cancer agents. As these viruses replicate in the host cell nucleus, they must gain access to the nucleus during infection. The PV minute virus of mice (MVM) and several other PVs transiently disrupt the nuclear envelope (NE) and enter the nucleus through the resulting breaks. However, the molecular basis of this unique nuclear entry pathway remains uncharacterized. In this study, we used MVM as a model to investigate the molecular mechanism by which PVs induce NE disruption during viral nuclear entry. By combining bioinformatics analyses, metabolic labeling assays, mutagenesis, and pharmacological inhibition, we identified a functional myristoylation site at the sequence 78GGKVGH83 of the unique portion of the capsid protein VP1 (VP1u) of MVM. Performing proteolytic cleavage studies with a peptide containing this myristoylation site or with purified virions, we found tryptophan at position 77 of MVM VP1u is susceptible to chymotrypsin cleavage, implying this cleavage exposes G (glycine) 78 at the N-terminus of VP1u for myristoylation. Subsequent experiments using inhibitors of myristoylation and cellular proteases with MVM-infected cells, or an imaging-based quantitative NE permeabilization assay, further indicate protein myristoylation and a chymotrypsin-like activity are essential for MVM to locally disrupt the NE during viral nuclear entry. We thus propose a model for the nuclear entry of MVM in which NE disruption is mediated by VP1u myristoylation after the intact capsid undergoes proteolytic processing to expose the required N-terminal G for myristoylation. IMPORTANCE Rodent parvoviruses (PVs), including minute virus of mice (MVM), have the ability to infect and kill cancer cells and thereby possess great potential in anti-cancer therapy. In fact, some of these viruses are currently being investigated in both preclinical studies and clinical trials to treat a wide variety of cancers. However, the detailed mechanism of how PVs enter the cell nucleus remains unknown. In this study, we for the first time demonstrated a chemical modification called "myristoylation" of a MVM protein plays an essential role in the nuclear entry of the virus. We also showed, in addition to protein myristoylation, a chymotrypsin-like activity, which may come from cellular proteasomes, is required for MVM to get myristoylated and enter the nucleus. These findings deepen our understanding on how MVM and other related PVs infect host cells and provide new insights for the development of PV-based anti-cancer therapies.
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15
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Ortega-Gonzalez P, Taylor G, Jangra RK, Tenorio R, Fernandez de Castro I, Mainou BA, Orchard RC, Wilen CB, Brigleb PH, Sojati J, Chandran K, Sachse M, Risco C, Dermody TS. Reovirus infection is regulated by NPC1 and endosomal cholesterol homeostasis. PLoS Pathog 2022; 18:e1010322. [PMID: 35263388 PMCID: PMC8906592 DOI: 10.1371/journal.ppat.1010322] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 01/28/2022] [Indexed: 11/19/2022] Open
Abstract
Cholesterol homeostasis is required for the replication of many viruses, including Ebola virus, hepatitis C virus, and human immunodeficiency virus-1. Niemann-Pick C1 (NPC1) is an endosomal-lysosomal membrane protein involved in cholesterol trafficking from late endosomes and lysosomes to the endoplasmic reticulum. We identified NPC1 in CRISPR and RNA interference screens as a putative host factor for infection by mammalian orthoreovirus (reovirus). Following internalization via clathrin-mediated endocytosis, the reovirus outer capsid is proteolytically removed, the endosomal membrane is disrupted, and the viral core is released into the cytoplasm where viral transcription, genome replication, and assembly take place. We found that reovirus infection is significantly impaired in cells lacking NPC1, but infection is restored by treatment of cells with hydroxypropyl-β-cyclodextrin, which binds and solubilizes cholesterol. Absence of NPC1 did not dampen infection by infectious subvirion particles, which are reovirus disassembly intermediates that bypass the endocytic pathway for infection of target cells. NPC1 is not required for reovirus attachment to the plasma membrane, internalization into cells, or uncoating within endosomes. Instead, NPC1 is required for delivery of transcriptionally active reovirus core particles from endosomes into the cytoplasm. These findings suggest that cholesterol homeostasis, ensured by NPC1 transport activity, is required for reovirus penetration into the cytoplasm, pointing to a new function for NPC1 and cholesterol homeostasis in viral infection.
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Affiliation(s)
- Paula Ortega-Gonzalez
- Cell Structure Laboratory, National Center for Biotechnology, CNB-CSIC, campus UAM, Cantoblanco, Madrid, Spain
- PhD Program in Molecular Biosciences, Autonoma de Madrid University, Madrid, Spain
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- Institute of Infection, Inflammation, and Immunity, UPMC Children’s Hospital of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Gwen Taylor
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- Institute of Infection, Inflammation, and Immunity, UPMC Children’s Hospital of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Rohit K. Jangra
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Raquel Tenorio
- Cell Structure Laboratory, National Center for Biotechnology, CNB-CSIC, campus UAM, Cantoblanco, Madrid, Spain
| | - Isabel Fernandez de Castro
- Cell Structure Laboratory, National Center for Biotechnology, CNB-CSIC, campus UAM, Cantoblanco, Madrid, Spain
| | - Bernardo A. Mainou
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Robert C. Orchard
- Department of Immunology, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Craig B. Wilen
- Departments of Laboratory Medicine and Immunobiology, Yale University School of Medicine, New Haven, Connecticut, United States of America
| | - Pamela H. Brigleb
- Institute of Infection, Inflammation, and Immunity, UPMC Children’s Hospital of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Jorna Sojati
- Institute of Infection, Inflammation, and Immunity, UPMC Children’s Hospital of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Kartik Chandran
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Martin Sachse
- Cell Structure Laboratory, National Center for Biotechnology, CNB-CSIC, campus UAM, Cantoblanco, Madrid, Spain
| | - Cristina Risco
- Cell Structure Laboratory, National Center for Biotechnology, CNB-CSIC, campus UAM, Cantoblanco, Madrid, Spain
| | - Terence S. Dermody
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- Institute of Infection, Inflammation, and Immunity, UPMC Children’s Hospital of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
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16
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Xia X, Wu W, Cui Y, Roy P, Zhou ZH. Bluetongue virus capsid protein VP5 perforates membranes at low endosomal pH during viral entry. Nat Microbiol 2021; 6:1424-1432. [PMID: 34702979 PMCID: PMC9015746 DOI: 10.1038/s41564-021-00988-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 09/22/2021] [Indexed: 01/25/2023]
Abstract
Bluetongue virus (BTV) is a non-enveloped virus and causes substantial morbidity and mortality in ruminants such as sheep. Fashioning a receptor-binding protein (VP2) and a membrane penetration protein (VP5) on the surface, BTV releases its genome-containing core (VP3 and VP7) into the host cell cytosol after perforation of the endosomal membrane. Unlike enveloped ones, the entry mechanisms of non-enveloped viruses into host cells remain poorly understood. Here we applied single-particle cryo-electron microscopy, cryo-electron tomography and structure-guided functional assays to characterize intermediate states of BTV cell entry in endosomes. Four structures of BTV at the resolution range of 3.4-3.9 Å show the different stages of structural rearrangement of capsid proteins on exposure to low pH, including conformational changes of VP5, stepwise detachment of VP2 and a small shift of VP7. In detail, sensing of the low-pH condition by the VP5 anchor domain triggers three major VP5 actions: projecting the hidden dagger domain, converting a surface loop to a protonated β-hairpin that anchors VP5 to the core and stepwise refolding of the unfurling domains into a six-helix stalk. Cryo-electron tomography structures of BTV interacting with liposomes show a length decrease of the VP5 stalk from 19.5 to 15.5 nm after its insertion into the membrane. Our structures, functional assays and structure-guided mutagenesis experiments combined indicate that this stalk, along with dagger domain and the WHXL motif, creates a single pore through the endosomal membrane that enables the viral core to enter the cytosol. Our study unveils the detailed mechanisms of BTV membrane penetration and showcases general methods to study cell entry of other non-enveloped viruses.
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Affiliation(s)
- Xian Xia
- Department of Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, USA
| | - Weining Wu
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Yanxiang Cui
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, USA
| | - Polly Roy
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Z Hong Zhou
- Department of Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA.
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, USA.
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17
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Hejtmánková A, Váňová J, Španielová H. Cell-penetrating peptides in the intracellular delivery of viral nanoparticles. VITAMINS AND HORMONES 2021; 117:47-76. [PMID: 34420585 DOI: 10.1016/bs.vh.2021.06.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cell-penetrating peptides (CPPs) are a promising tool for the intracellular delivery of cargo. Due to their ability to cross membranes while also cotransporting various cargoes, they offer great potential for biomedical applications. Several CPPs have been derived from viral proteins with natural roles in the viral replication cycle that require them to breach or fuse to cellular membranes. Additionally, the ability of viruses to cross membranes makes viruses and virus-based particles a convenient model for research on nanoparticle delivery and nanoparticle-mediated gene therapy. In this chapter, we aim to characterize CPPs derived from both structural and nonstructural viral proteins. Their function as enhancers of viral infection and transduction by viral nanoparticles as well as the main features of viral CPPs employed in intracellular cargo delivery are summarized to emphasize their potential use in nanomedicine.
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Affiliation(s)
- Alžběta Hejtmánková
- Department of Genetics and Microbiology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Jana Váňová
- Department of Genetics and Microbiology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Hana Španielová
- Department of Genetics and Microbiology, Faculty of Science, Charles University, Prague, Czech Republic; Institute of Organic Chemistry and Biochemistry of the CAS, Prague, Czech Republic.
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18
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Ykema M, Tao YJ. Structural Insights into the Human Astrovirus Capsid. Viruses 2021; 13:v13050821. [PMID: 34062934 PMCID: PMC8147390 DOI: 10.3390/v13050821] [Citation(s) in RCA: 9] [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: 04/02/2021] [Revised: 04/26/2021] [Accepted: 04/28/2021] [Indexed: 12/11/2022] Open
Abstract
Astroviruses (AstVs) are non-enveloped, positive single-stranded RNA viruses that cause a wide range of inflammatory diseases in mammalian and avian hosts. The T = 3 viral capsid is unique in its ability to infect host cells in a process driven by host proteases. Intercellular protease cleavages allow for viral egress from a cell, while extracellular cleavages allow for the virus to enter a new host cell to initiate infection. High-resolution models of the capsid core indicate a large, exposed region enriched with protease cleavage sites. The virus spike protein allows for binding to target cells and is the major target for naturally occurring and engineered neutralizing antibodies. During maturation, the capsid goes through significant structural changes including the loss of many surface spikes. The capsid interacts with host membranes during the virus life cycle at multiple stages such as assembly, host cell entry and exit. This review will cover recent findings and insights related to the structure of the capsid and its function. Further understanding of the viral capsid structure and maturation process can contribute to new vaccines, gastric therapeutics, and viral engineering applications.
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19
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He WR, Cao LB, Yang YL, Hua D, Hu MM, Shu HB. VRK2 is involved in the innate antiviral response by promoting mitostress-induced mtDNA release. Cell Mol Immunol 2021; 18:1186-1196. [PMID: 33785841 PMCID: PMC8093274 DOI: 10.1038/s41423-021-00673-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 03/07/2021] [Indexed: 12/15/2022] Open
Abstract
Mitochondrial stress (mitostress) triggered by viral infection or mitochondrial dysfunction causes the release of mitochondrial DNA (mtDNA) into the cytosol and activates the cGAS-mediated innate immune response. The regulation of mtDNA release upon mitostress remains uncharacterized. Here, we identified mitochondria-associated vaccinia virus-related kinase 2 (VRK2) as a key regulator of this process. VRK2 deficiency inhibited the induction of antiviral genes and caused earlier and higher mortality in mice after viral infection. Upon viral infection, VRK2 associated with voltage-dependent anion channel 1 (VDAC1) and promoted VDAC1 oligomerization and mtDNA release, leading to the cGAS-mediated innate immune response. VRK2 was also required for mtDNA release and cGAS-mediated innate immunity triggered by nonviral factors that cause Ca2+ overload but was not required for the cytosolic nucleic acid-triggered innate immune response. Thus, VRK2 plays a crucial role in the mtDNA-triggered innate immune response and may be a potential therapeutic target for infectious and autoimmune diseases associated with mtDNA release.
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Affiliation(s)
- Wen-Rui He
- Department of Infectious Diseases, Frontier Science Center for Immunology and Metabolism, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan, China
- Research Unit of Innate Immune and Inflammatory Diseases, Chinese Academy of Medical Sciences, Wuhan, China
| | - Li-Bo Cao
- Department of Infectious Diseases, Frontier Science Center for Immunology and Metabolism, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan, China
- Research Unit of Innate Immune and Inflammatory Diseases, Chinese Academy of Medical Sciences, Wuhan, China
| | - Yu-Lin Yang
- Department of Infectious Diseases, Frontier Science Center for Immunology and Metabolism, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan, China
- Research Unit of Innate Immune and Inflammatory Diseases, Chinese Academy of Medical Sciences, Wuhan, China
| | - Duo Hua
- Department of Infectious Diseases, Frontier Science Center for Immunology and Metabolism, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan, China
- Research Unit of Innate Immune and Inflammatory Diseases, Chinese Academy of Medical Sciences, Wuhan, China
| | - Ming-Ming Hu
- Department of Infectious Diseases, Frontier Science Center for Immunology and Metabolism, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan, China.
- Research Unit of Innate Immune and Inflammatory Diseases, Chinese Academy of Medical Sciences, Wuhan, China.
| | - Hong-Bing Shu
- Department of Infectious Diseases, Frontier Science Center for Immunology and Metabolism, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan, China.
- Research Unit of Innate Immune and Inflammatory Diseases, Chinese Academy of Medical Sciences, Wuhan, China.
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20
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Jana AK, May ER. Atomistic dynamics of a viral infection process: Release of membrane lytic peptides from a non-enveloped virus. SCIENCE ADVANCES 2021; 7:7/16/eabe1761. [PMID: 33853772 PMCID: PMC8046363 DOI: 10.1126/sciadv.abe1761] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 02/23/2021] [Indexed: 05/13/2023]
Abstract
Molecular simulations have played an instrumental role in uncovering the structural dynamics and physical properties of virus capsids. In this work, we move beyond equilibrium physicochemical characterization of a virus system to study a stage of the infection process that is required for viral proliferation. Despite many biochemical and functional studies, the molecular mechanism of host cell entry by non-enveloped viruses remains largely unresolved. Flock House virus (FHV) is a model system for non-enveloped viruses and is the subject of the current study. FHV infects through the acid-dependent endocytic pathway, where low pH triggers externalization of membrane-disrupting (γ) peptides from the capsid interior. Using all-atom equilibrium and enhanced sampling simulations, the mechanism and energetics of γ peptide liberation and the effect of pH on this process are investigated. Our computations agree with experimental findings and reveal nanoscopic details regarding the pH control mechanism, which are not readily accessible in experiments.
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Affiliation(s)
- Asis K Jana
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA
| | - Eric R May
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA.
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21
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Zhou J, Krishnan N, Jiang Y, Fang RH, Zhang L. Nanotechnology for virus treatment. NANO TODAY 2021; 36:101031. [PMID: 33519948 PMCID: PMC7836394 DOI: 10.1016/j.nantod.2020.101031] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 11/09/2020] [Accepted: 11/11/2020] [Indexed: 04/14/2023]
Abstract
The continued emergence of novel viruses poses a significant threat to global health. Uncontrolled outbreaks can result in pandemics that have the potential to overburden our healthcare and economic systems. While vaccination is a conventional modality that can be employed to promote herd immunity, antiviral vaccines can only be applied prophylactically and do little to help patients who have already contracted viral infections. During the early stages of a disease outbreak when vaccines are unavailable, therapeutic antiviral drugs can be used as a stopgap solution. However, these treatments do not always work against emerging viral strains and can be accompanied by adverse effects that sometimes outweigh the benefits. Nanotechnology has the potential to overcome many of the challenges facing current antiviral therapies. For example, nanodelivery vehicles can be employed to drastically improve the pharmacokinetic profile of antiviral drugs while reducing their systemic toxicity. Other unique nanomaterials can be leveraged for their virucidal or virus-neutralizing properties. In this review, we discuss recent developments in antiviral nanotherapeutics and provide a perspective on the application of nanotechnology to the SARS-CoV-2 outbreak and future virus pandemics.
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Affiliation(s)
- Jiarong Zhou
- Department of NanoEngineering, Chemical Engineering Program, and Moores Cancer Center, University of California San Diego, La Jolla, CA, 92093, USA
| | - Nishta Krishnan
- Department of NanoEngineering, Chemical Engineering Program, and Moores Cancer Center, University of California San Diego, La Jolla, CA, 92093, USA
| | - Yao Jiang
- Department of NanoEngineering, Chemical Engineering Program, and Moores Cancer Center, University of California San Diego, La Jolla, CA, 92093, USA
| | - Ronnie H Fang
- Department of NanoEngineering, Chemical Engineering Program, and Moores Cancer Center, University of California San Diego, La Jolla, CA, 92093, USA
| | - Liangfang Zhang
- Department of NanoEngineering, Chemical Engineering Program, and Moores Cancer Center, University of California San Diego, La Jolla, CA, 92093, USA
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22
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Jana AK, May ER. Structural and dynamic asymmetry in icosahedrally symmetric virus capsids. Curr Opin Virol 2020; 45:8-16. [PMID: 32615360 PMCID: PMC7746594 DOI: 10.1016/j.coviro.2020.06.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 05/30/2020] [Accepted: 06/04/2020] [Indexed: 02/06/2023]
Abstract
A common characteristic of virus capsids is icosahedral symmetry, yet these highly symmetric structures can display asymmetric features within their virions and undergo asymmetric dynamics. The fields of structural and computational biology have entered a new realm in the investigation of virus infection mechanisms, with the ability to observe symmetry-breaking features. This review will cover important studies on icosahedral virus structure and dynamics, covering both symmetric and asymmetric conformational changes. However, the main emphasis of the review will be towards recent studies employing cryo-electron microscopy or molecular dynamics simulations, which can uncover asymmetric aspects of these systems relevant to understanding viral physical-chemical properties and their biological impact.
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Affiliation(s)
- Asis K Jana
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA
| | - Eric R May
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA.
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23
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Reovirus σ1 Conformational Flexibility Modulates the Efficiency of Host Cell Attachment. J Virol 2020; 94:JVI.01163-20. [PMID: 32938765 DOI: 10.1128/jvi.01163-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 09/09/2020] [Indexed: 02/07/2023] Open
Abstract
Reovirus attachment protein σ1 is a trimeric molecule containing tail, body, and head domains. During infection, σ1 engages sialylated glycans and junctional adhesion molecule-A (JAM-A), triggering uptake into the endocytic compartment, where virions are proteolytically converted to infectious subvirion particles (ISVPs). Further disassembly allows σ1 release and escape of transcriptionally active reovirus cores into the cytosol. Electron microscopy has revealed a distinct conformational change in σ1 from a compact form on virions to an extended form on ISVPs. To determine the importance of σ1 conformational mobility, we used reverse genetics to introduce cysteine mutations that can cross-link σ1 by establishing disulfide bonds between structurally adjacent sites in the tail, body, and head domains. We detected phenotypic differences among the engineered viruses. A mutant with a cysteine pair in the head domain replicates with enhanced kinetics, forms large plaques, and displays increased avidity for JAM-A relative to the parental virus, mimicking properties of ISVPs. However, unlike ISVPs, particles containing cysteine mutations that cross-link the head domain uncoat and transcribe viral positive-sense RNA with kinetics similar to the parental virus and are sensitive to ammonium chloride, which blocks virion-to-ISVP conversion. Together, these data suggest that σ1 conformational flexibility modulates the efficiency of reovirus host cell attachment.IMPORTANCE Nonenveloped virus entry is an incompletely understood process. For reovirus, the functional significance of conformational rearrangements in the attachment protein, σ1, that occur during entry and particle uncoating are unknown. We engineered and characterized reoviruses containing cysteine mutations that cross-link σ1 monomers in nonreducing conditions. We found that the introduction of a cysteine pair in the receptor-binding domain of σ1 yielded a virus that replicates with faster kinetics than the parental virus and forms larger plaques. Using functional assays, we found that cross-linking the σ1 receptor-binding domain modulates reovirus attachment but not uncoating or transcription. These data suggest that σ1 conformational rearrangements mediate the efficiency of reovirus host cell binding.
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24
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Uhlorn BL, Jackson R, Li S, Bratton SM, Van Doorslaer K, Campos SK. Vesicular trafficking permits evasion of cGAS/STING surveillance during initial human papillomavirus infection. PLoS Pathog 2020; 16:e1009028. [PMID: 33253291 PMCID: PMC7728285 DOI: 10.1371/journal.ppat.1009028] [Citation(s) in RCA: 31] [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: 04/08/2020] [Revised: 12/10/2020] [Accepted: 10/02/2020] [Indexed: 12/26/2022] Open
Abstract
Oncogenic human papillomaviruses (HPVs) replicate in differentiating epithelium, causing 5% of cancers worldwide. Like most other DNA viruses, HPV infection initiates after trafficking viral genome (vDNA) to host cell nuclei. Cells possess innate surveillance pathways to detect microbial components or physiological stresses often associated with microbial infections. One of these pathways, cGAS/STING, induces IRF3-dependent antiviral interferon (IFN) responses upon detection of cytosolic DNA. Virion-associated vDNA can activate cGAS/STING during initial viral entry and uncoating/trafficking, and thus cGAS/STING is an obstacle to many DNA viruses. HPV has a unique vesicular trafficking pathway compared to many other DNA viruses. As the capsid uncoats within acidic endosomal compartments, minor capsid protein L2 protrudes across vesicular membranes to facilitate transport of vDNA to the Golgi. L2/vDNA resides within the Golgi lumen until G2/M, whereupon vesicular L2/vDNA traffics along spindle microtubules, tethering to chromosomes to access daughter cell nuclei. L2/vDNA-containing vesicles likely remain intact until G1, following nuclear envelope reformation. We hypothesize that this unique vesicular trafficking protects HPV from cGAS/STING surveillance. Here, we investigate cGAS/STING responses to HPV infection. DNA transfection resulted in acute cGAS/STING activation and downstream IFN responses. In contrast, HPV infection elicited minimal cGAS/STING and IFN responses. To determine the role of vesicular trafficking in cGAS/STING evasion, we forced premature viral penetration of vesicular membranes with membrane-perturbing cationic lipids. Such treatment renders a non-infectious trafficking-defective mutant HPV infectious, yet susceptible to cGAS/STING detection. Overall, HPV evades cGAS/STING by its unique subcellular trafficking, a property that may contribute to establishment of infection.
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Affiliation(s)
- Brittany L. Uhlorn
- Cancer Biology Graduate Interdisciplinary Program, The University of Arizona, Tucson, Arizona, United States of America
| | - Robert Jackson
- School of Animal & Comparative Biomedical Sciences, The University of Arizona, Tucson, Arizona, United States of America
| | - Shuaizhi Li
- Department of Immunobiology, The University of Arizona, Tucson, Arizona, United States of America
| | - Shauna M. Bratton
- Department of Physiology, The University of Arizona, Tucson, Arizona, United States of America
| | - Koenraad Van Doorslaer
- Cancer Biology Graduate Interdisciplinary Program, The University of Arizona, Tucson, Arizona, United States of America
- School of Animal & Comparative Biomedical Sciences, The University of Arizona, Tucson, Arizona, United States of America
- Department of Immunobiology, The University of Arizona, Tucson, Arizona, United States of America
- BIO5 Institute, The University of Arizona, Tucson, Arizona, United States of America
- Genetics Graduate Interdisciplinary Program, The University of Arizona, Tucson, Arizona, United States of America
| | - Samuel K. Campos
- Cancer Biology Graduate Interdisciplinary Program, The University of Arizona, Tucson, Arizona, United States of America
- Department of Immunobiology, The University of Arizona, Tucson, Arizona, United States of America
- BIO5 Institute, The University of Arizona, Tucson, Arizona, United States of America
- Department of Molecular & Cellular Biology, The University of Arizona, Tucson, Arizona, United States of America
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25
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Su X, Wang Q, Wen Y, Jiang S, Lu L. Protein- and Peptide-Based Virus Inactivators: Inactivating Viruses Before Their Entry Into Cells. Front Microbiol 2020; 11:1063. [PMID: 32523582 PMCID: PMC7261908 DOI: 10.3389/fmicb.2020.01063] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Accepted: 04/29/2020] [Indexed: 12/20/2022] Open
Abstract
Infectious diseases caused by human immunodeficiency virus (HIV) and other highly pathogenic enveloped viruses, have threatened the global public health. Most antiviral drugs act as passive defenders to inhibit viral replication inside the cell, while a few of them function as gate keepers to combat viruses outside the cell, including fusion inhibitors, e.g., enfuvirtide, and receptor antagonists, e.g., maraviroc, as well as virus inactivators (including attachment inhibitors). Different from fusion inhibitors and receptor antagonists that must act in the presence of target cells, virus inactivators can actively inactivate cell-free virions in the blood, through interaction with one or more sites in the envelope glycoproteins (Envs) on virions. Notably, a number of protein- and peptide-based virus inactivators (PPVIs) under development are expected to have a better utilization rate than the current antiviral drugs and be safer for in vivo human application than the chemical-based virus inactivators. Here we have highlighted recent progress in developing PPVIs against several important enveloped viruses, including HIV, influenza virus, Zika virus (ZIKV), dengue virus (DENV), and herpes simplex virus (HSV), and the potential use of PPVIs for urgent treatment of infection by newly emerging or re-emerging viruses.
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Affiliation(s)
- Xiaojie Su
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Qian Wang
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Yumei Wen
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Shibo Jiang
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Fudan University, Shanghai, China.,Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY, United States
| | - Lu Lu
- Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS), School of Basic Medical Sciences, Fudan University, Shanghai, China
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26
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Ubqln4 Facilitates Endoplasmic Reticulum-to-Cytosol Escape of a Nonenveloped Virus during Infection. J Virol 2020; 94:JVI.00103-20. [PMID: 32161173 DOI: 10.1128/jvi.00103-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 03/09/2020] [Indexed: 12/14/2022] Open
Abstract
The nonenveloped polyomavirus simian virus 40 (SV40) must penetrate the host endoplasmic reticulum (ER) membrane to enter the cytosol in order to promote infection. How this is accomplished is not entirely clear. Here, we demonstrate that the cytosolic chaperone Ubiquilin4 (Ubqln4) binds directly to the ER membrane J proteins B12 and B14. Strategically localized at the ER-cytosol interface, Ubqln4 captures SV40 emerging from the ER, thereby facilitating escape of the virus from the ER into the cytosol, which leads to infection. Strikingly, Ubqln4 engages the J proteins in a J-domain-independent manner, in contrast to the previously reported Hsc70-Hsp105-SGTA-Bag2 cytosolic complex that also mediates SV40 ER-to-cytosol transport. Our results also reveal that the H domain and STI1 motif (1-2) of Ubqln4 support J protein binding, essential for SV40 infection. Together, these data further clarify the molecular basis by which a nonenveloped virus escapes a host membrane during infectious entry.IMPORTANCE How a nonenveloped virus escapes from a host membrane to promote infection remains enigmatic. In the case of the nonenveloped polyomavirus SV40, penetration of the ER membrane to reach the cytosol is a decisive virus infection step. In this study, we found a new host factor called Ubqln4 that facilitates escape of SV40 from the ER into the cytosol, thereby providing a path for the virus to enter the nucleus to cause infection.
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27
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Jayawardena N, Poirier JT, Burga LN, Bostina M. Virus-Receptor Interactions and Virus Neutralization: Insights for Oncolytic Virus Development. Oncolytic Virother 2020; 9:1-15. [PMID: 32185149 PMCID: PMC7064293 DOI: 10.2147/ov.s186337] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 02/09/2020] [Indexed: 12/24/2022] Open
Abstract
Oncolytic viruses (OVs) are replication competent agents that selectively target cancer cells. After penetrating the tumor cell, viruses replicate and eventually trigger cell lysis, releasing the new viral progeny, which at their turn will attack and kill neighbouring cells. The ability of OVs to self-amplify within the tumor while sparing normal cells can provide several advantages including the capacity to encode and locally produce therapeutic protein payloads, and to prime the host immune system. OVs targeting of cancer cells is mediated by host factors that are differentially expressed between normal tissue and tumors, including viral receptors and internalization factors. In this review article, we will discuss the evolution of oncolytic viruses that have reached the stage of clinical trials, their mechanisms of oncolysis, cellular receptors, strategies for targeting cancers, viral neutralization and developments to bypass virus neutralization.
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Affiliation(s)
- Nadishka Jayawardena
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - John T Poirier
- Department of Medicine and Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Laura N Burga
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Mihnea Bostina
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- Otago Micro and Nano Imaging, University of Otago, Dunedin, New Zealand
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28
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Kane JR, Fong S, Shaul J, Frommlet A, Frank AO, Knapp M, Bussiere DE, Kim P, Ornelas E, Cuellar C, Hyrina A, Abend JR, Wartchow CA. A polyomavirus peptide binds to the capsid VP1 pore and has potent antiviral activity against BK and JC polyomaviruses. eLife 2020; 9:50722. [PMID: 31960795 PMCID: PMC6974358 DOI: 10.7554/elife.50722] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 12/30/2019] [Indexed: 12/18/2022] Open
Abstract
In pursuit of therapeutics for human polyomaviruses, we identified a peptide derived from the BK polyomavirus (BKV) minor structural proteins VP2/3 that is a potent inhibitor of BKV infection with no observable cellular toxicity. The thirteen-residue peptide binds to major structural protein VP1 with single-digit nanomolar affinity. Alanine-scanning of the peptide identified three key residues, substitution of each of which results in ~1000 fold loss of binding affinity with a concomitant reduction in antiviral activity. Structural studies demonstrate specific binding of the peptide to the pore of pentameric VP1. Cell-based assays demonstrate nanomolar inhibition (EC50) of BKV infection and suggest that the peptide acts early in the viral entry pathway. Homologous peptide exhibits similar binding to JC polyomavirus VP1 and inhibits infection with similar potency to BKV in a model cell line. Lastly, these studies validate targeting the VP1 pore as a novel strategy for the development of anti-polyomavirus agents.
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Affiliation(s)
- Joshua R Kane
- Infectious Diseases, Novartis Institutes for BioMedical Research, Emeryville, United States.,Global Discovery Chemistry, Novartis Institutes for BioMedical Research, Emeryville, United States
| | - Susan Fong
- Infectious Diseases, Novartis Institutes for BioMedical Research, Emeryville, United States
| | - Jacob Shaul
- Chemical Biology and Therapeutics, Novartis Institutes for BioMedical Research, Emeryville, United States
| | - Alexandra Frommlet
- Global Discovery Chemistry, Novartis Institutes for BioMedical Research, Emeryville, United States
| | - Andreas O Frank
- Global Discovery Chemistry, Novartis Institutes for BioMedical Research, Emeryville, United States
| | - Mark Knapp
- Global Discovery Chemistry, Novartis Institutes for BioMedical Research, Emeryville, United States
| | - Dirksen E Bussiere
- Global Discovery Chemistry, Novartis Institutes for BioMedical Research, Emeryville, United States
| | - Peter Kim
- Infectious Diseases, Novartis Institutes for BioMedical Research, Emeryville, United States
| | - Elizabeth Ornelas
- Global Discovery Chemistry, Novartis Institutes for BioMedical Research, Emeryville, United States
| | - Carlos Cuellar
- Global Discovery Chemistry, Novartis Institutes for BioMedical Research, Emeryville, United States
| | - Anastasia Hyrina
- Chemical Biology and Therapeutics, Novartis Institutes for BioMedical Research, Emeryville, United States
| | - Johanna R Abend
- Infectious Diseases, Novartis Institutes for BioMedical Research, Emeryville, United States
| | - Charles A Wartchow
- Global Discovery Chemistry, Novartis Institutes for BioMedical Research, Emeryville, United States
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29
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Inflammation During Virus Infection: Swings and Roundabouts. DYNAMICS OF IMMUNE ACTIVATION IN VIRAL DISEASES 2020. [PMCID: PMC7121364 DOI: 10.1007/978-981-15-1045-8_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Inflammation constitutes a concerted series of cellular and molecular responses that follow disturbance of systemic homeostasis, by either toxins or infectious organisms. Leukocytes modulate inflammation through production of secretory mediators, like cytokines and chemokines, which work in an autocrine and/or paracrine manner. These mediators can either promote or attenuate the inflammatory response and depending on differential temporal and spatial expression play a crucial role in the outcome of infection. Even though the objective is clearance of the pathogen with minimum damage to host, the pathogenesis of multiple human pathogenic viruses has been suggested to emanate from a dysregulation of the inflammatory response, sometimes with fatal consequences. This review discusses the nature and the outcome of inflammatory response, which is triggered in the human host subsequent to infection by single-sense plus-strand RNA viruses. In view of such harmful effects of a dysregulated inflammatory response, an exogenous regulation of these reactions by either interference or supplementation of critical regulators has been suggested. Currently multiple such factors are being tested for their beneficial and adverse effects. A successful use of such an approach in diseases of viral etiology can potentially protect the affected individual without directly affecting the virus life cycle. Further, such approaches whenever applicable would be useful in mitigating death and/or debility that is caused by the infection of those viruses which have proven particularly difficult to control by either prophylactic vaccines and/or therapeutic strategies using specific antiviral drugs.
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30
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Structural Dynamics of Nonenveloped Virus Disassembly Intermediates. J Virol 2019; 93:JVI.01115-19. [PMID: 31484752 DOI: 10.1128/jvi.01115-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 08/14/2019] [Indexed: 12/16/2022] Open
Abstract
The stability of icosahedral viruses is crucial for protecting the viral genome during transit; however, successful infection requires eventual disassembly of the capsid. A comprehensive understanding of how stable, uniform icosahedrons disassemble remains elusive, mainly due to the complexities involved in isolating transient intermediates. We utilized incremental heating to systematically characterize the disassembly pathway of a model nonenveloped virus and identified an intriguing link between virus maturation and disassembly. Further, we isolated and characterized two intermediates by cryo-electron microscopy and three-dimensional reconstruction, without imposing icosahedral symmetry. The first intermediate displayed a series of major, asymmetric alterations, whereas the second showed that the act of genome release, through the 2-fold axis, is actually confined to a small section on the capsid. Our study thus presents a comprehensive structural analysis of nonenveloped virus disassembly and emphasizes the asymmetric nature of programmed conformational changes.IMPORTANCE Disassembly or uncoating of an icosahedral capsid is a crucial step during infection by nonenveloped viruses. However, the dynamic and transient nature of the disassembly process makes it challenging to isolate intermediates in a temporal, stepwise manner for structural characterization. Using controlled, incremental heating, we isolated two disassembly intermediates: "eluted particles" and "puffed particles" of an insect nodavirus, Flock House virus (FHV). Cryo-electron microscopy and three-dimensional reconstruction of the FHV disassembly intermediates indicated that disassembly-related conformational alterations are minimally global and largely local, leading to asymmetry in the particle and eventual genome release without complete disintegration of the icosahedron.
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31
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Dey D, Siddiqui SI, Mamidi P, Ghosh S, Kumar CS, Chattopadhyay S, Ghosh S, Banerjee M. The effect of amantadine on an ion channel protein from Chikungunya virus. PLoS Negl Trop Dis 2019; 13:e0007548. [PMID: 31339886 PMCID: PMC6655611 DOI: 10.1371/journal.pntd.0007548] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Accepted: 06/11/2019] [Indexed: 01/01/2023] Open
Abstract
Viroporins like influenza A virus M2, hepatitis C virus p7, HIV-1 Vpu and picornavirus 2B associate with host membranes, and create hydrophilic corridors, which are critical for viral entry, replication and egress. The 6K proteins from alphaviruses are conjectured to be viroporins, essential during egress of progeny viruses from host membranes, although the analogue in Chikungunya Virus (CHIKV) remains relatively uncharacterized. Using a combination of electrophysiology, confocal and electron microscopy, and molecular dynamics simulations we show for the first time that CHIKV 6K is an ion channel forming protein that primarily associates with endoplasmic reticulum (ER) membranes. The ion channel activity of 6K can be inhibited by amantadine, an antiviral developed against the M2 protein of Influenza A virus; and CHIKV infection of cultured cells can be effectively inhibited in presence of this drug. Our study provides crucial mechanistic insights into the functionality of 6K during CHIKV-host interaction and suggests that 6K is a potential therapeutic drug target, with amantadine and its derivatives being strong candidates for further development. Chikungunya fever is a severe crippling illness caused by the arthropod-borne virus CHIKV. Originally from the African subcontinent, the virus has now spread worldwide and is responsible for substantial morbidity and economic loss. The existing treatment against CHIKV is primarily symptomatic, and it is imperative that specific therapeutics be devised. The present study provides detailed insight into the functionality of 6K, an ion channel forming protein of CHIKV. Amantadine, a known antiviral against influenza virus, also inhibits CHIKV replication in cell culture and drastically alters the morphology of virus particles. This work highlights striking parallels among functionalities of virus-encoded membrane-interacting proteins, which may be exploited for developing broad-spectrum antivirals.
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Affiliation(s)
- Debajit Dey
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, India
| | | | | | - Sukanya Ghosh
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, India
| | | | | | - Subhendu Ghosh
- Department of Biophysics, University of Delhi (South Campus), Delhi, India
| | - Manidipa Banerjee
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, India
- * E-mail:
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32
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Abstract
Viruses must navigate the complex endomembranous network of the host cell to cause infection. In the case of a non-enveloped virus that lacks a surrounding lipid bilayer, endocytic uptake from the plasma membrane is not sufficient to cause infection. Instead, the virus must travel within organelle membranes to reach a specific cellular destination that supports exposure or arrival of the virus to the cytosol. This is achieved by viral penetration across a host endomembrane, ultimately enabling entry of the virus into the nucleus to initiate infection. In this review, we discuss the entry mechanisms of three distinct non-enveloped DNA viruses-adenovirus (AdV), human papillomavirus (HPV), and polyomavirus (PyV)-highlighting how each exploit different intracellular transport machineries and membrane penetration apparatus associated with the endosome, Golgi, and endoplasmic reticulum (ER) membrane systems to infect a host cell. These processes not only illuminate a highly-coordinated interplay between non-enveloped viruses and their host, but may provide new strategies to combat non-enveloped virus-induced diseases.
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Affiliation(s)
- Chelsey C Spriggs
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Mara C Harwood
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, United States; Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Billy Tsai
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, United States; Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI, United States.
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33
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Graziano VR, Wei J, Wilen CB. Norovirus Attachment and Entry. Viruses 2019; 11:E495. [PMID: 31151248 PMCID: PMC6630345 DOI: 10.3390/v11060495] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 05/24/2019] [Accepted: 05/25/2019] [Indexed: 12/19/2022] Open
Abstract
Human norovirus is a major human pathogen causing the majority of cases of viral gastroenteritis globally. Viral entry is the first step of the viral life cycle and is a significant determinant of cell tropism, host range, immune interactions, and pathogenesis. Bile salts and histo-blood group antigens are key mediators of norovirus entry; however, the molecular mechanisms by which these molecules promote infection and the identity of a potential human norovirus receptor remain unknown. Recently, there have been several important advances in norovirus entry biology including the identification of CD300lf as the receptor for murine norovirus and of the role of the minor capsid protein VP2 in viral genome release. Here, we will review the current understanding about norovirus attachment and entry and highlight important future directions.
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Affiliation(s)
- Vincent R Graziano
- Departments of Laboratory Medicine and Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA.
| | - Jin Wei
- Departments of Laboratory Medicine and Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA.
| | - Craig B Wilen
- Departments of Laboratory Medicine and Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA.
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Hilterbrand AT, Heldwein EE. Go go gadget glycoprotein!: HSV-1 draws on its sizeable glycoprotein tool kit to customize its diverse entry routes. PLoS Pathog 2019; 15:e1007660. [PMID: 31071197 PMCID: PMC6508585 DOI: 10.1371/journal.ppat.1007660] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Affiliation(s)
- Adam T. Hilterbrand
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Ekaterina E. Heldwein
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- * E-mail:
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Selection and Characterization of a Reovirus Mutant with Increased Thermostability. J Virol 2019; 93:JVI.00247-19. [PMID: 30787157 DOI: 10.1128/jvi.00247-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 02/13/2019] [Indexed: 12/26/2022] Open
Abstract
The environment represents a significant barrier to infection. Physical stressors (heat) or chemical agents (ethanol) can render virions noninfectious. As such, discrete proteins are necessary to stabilize the dual-layered structure of mammalian orthoreovirus (reovirus). The outer capsid participates in cell entry: (i) σ3 is degraded to generate the infectious subviral particle, and (ii) μ1 facilitates membrane penetration and subsequent core delivery. μ1-σ3 interactions also prevent inactivation; however, this activity is not fully characterized. Using forward and reverse genetic approaches, we identified two mutations (μ1 M258I and σ3 S344P) within heat-resistant strains. σ3 S344P was sufficient to enhance capsid integrity and to reduce protease sensitivity. Moreover, these changes impaired replicative fitness in a reassortant background. This work reveals new details regarding the determinants of reovirus stability.IMPORTANCE Nonenveloped viruses rely on protein-protein interactions to shield their genomes from the environment. The capsid, or protective shell, must also disassemble during cell entry. In this work, we identified a determinant within mammalian orthoreovirus that regulates heat resistance, disassembly kinetics, and replicative fitness. Together, these findings show capsid function is balanced for optimal replication and for spread to a new host.
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Components of the Reovirus Capsid Differentially Contribute to Stability. J Virol 2019; 93:JVI.01894-18. [PMID: 30381491 DOI: 10.1128/jvi.01894-18] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 10/24/2018] [Indexed: 12/13/2022] Open
Abstract
The mammalian orthoreovirus (reovirus) outer capsid is composed of 200 μ1-σ3 heterohexamers and a maximum of 12 σ1 trimers. During cell entry, σ3 is degraded by luminal or intracellular proteases to generate the infectious subviral particle (ISVP). When ISVP formation is prevented, reovirus fails to establish a productive infection, suggesting proteolytic priming is required for entry. ISVPs are then converted to ISVP*s, which is accompanied by μ1 rearrangements. The μ1 and σ3 proteins confer resistance to inactivating agents; however, neither the impact on capsid properties nor the mechanism (or basis) of inactivation is fully understood. Here, we utilized T1L/T3D M2 and T3D/T1L S4 to investigate the determinants of reovirus stability. Both reassortants encode mismatched subunits. When μ1-σ3 were derived from different strains, virions resembled wild-type particles in structure and protease sensitivity. T1L/T3D M2 and T3D/T1L S4 ISVPs were less thermostable than wild-type ISVPs. In contrast, virions were equally susceptible to heating. Virion associated μ1 adopted an ISVP*-like conformation concurrent with inactivation; σ3 preserves infectivity by preventing μ1 rearrangements. Moreover, thermostability was enhanced by a hyperstable variant of μ1. Unlike the outer capsid, the inner capsid (core) was highly resistant to elevated temperatures. The dual layered architecture allowed for differential sensitivity to inactivating agents.IMPORTANCE Nonenveloped and enveloped viruses are exposed to the environment during transmission to a new host. Protein-protein and/or protein-lipid interactions stabilize the particle and protect the viral genome. Mammalian orthoreovirus (reovirus) is composed of two concentric, protein shells. The μ1 and σ3 proteins form the outer capsid; contacts between neighboring subunits are thought to confer resistance to inactivating agents. We further investigated the determinants of reovirus stability. The outer capsid was disrupted concurrent with the loss of infectivity; virion associated μ1 rearranged into an altered conformation. Heat sensitivity was controlled by σ3; however, particle integrity was enhanced by a single μ1 mutation. In contrast, the inner capsid (core) displayed superior resistance to heating. These findings reveal structural components that differentially contribute to reovirus stability.
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Zhang P, Monteiro da Silva G, Deatherage C, Burd C, DiMaio D. Cell-Penetrating Peptide Mediates Intracellular Membrane Passage of Human Papillomavirus L2 Protein to Trigger Retrograde Trafficking. Cell 2018; 174:1465-1476.e13. [PMID: 30122350 PMCID: PMC6128760 DOI: 10.1016/j.cell.2018.07.031] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 07/09/2018] [Accepted: 07/23/2018] [Indexed: 10/28/2022]
Abstract
Cell-penetrating peptides (CPPs) are short protein segments that can transport cargos into cells. Although CPPs are widely studied as potential drug delivery tools, their role in normal cell physiology is poorly understood. Early during infection, the L2 capsid protein of human papillomaviruses binds retromer, a cytoplasmic trafficking factor required for delivery of the incoming non-enveloped virus into the retrograde transport pathway. Here, we show that the C terminus of HPV L2 proteins contains a conserved cationic CPP that drives passage of a segment of the L2 protein through the endosomal membrane into the cytoplasm, where it binds retromer, thereby sorting the virus into the retrograde pathway for transport to the trans-Golgi network. These experiments define the cell-autonomous biological role of a CPP in its natural context and reveal how a luminal viral protein engages an essential cytoplasmic entry factor.
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Affiliation(s)
- Pengwei Zhang
- Department of Genetics, Yale School of Medicine, New Haven, CT 06520-8005, USA
| | | | - Catherine Deatherage
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520-8002, USA
| | - Christopher Burd
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520-8002, USA
| | - Daniel DiMaio
- Department of Genetics, Yale School of Medicine, New Haven, CT 06520-8005, USA; Department of Therapeutic Radiology, Yale School of Medicine, New Haven, CT 06520-8040, USA; Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT 06520-8024, USA; Yale Cancer Center, New Haven, CT 06520-8028, USA.
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Pluta R, Espinosa M. Antisense and yet sensitive: Copy number control of rolling circle-replicating plasmids by small RNAs. WILEY INTERDISCIPLINARY REVIEWS-RNA 2018; 9:e1500. [PMID: 30074293 DOI: 10.1002/wrna.1500] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 06/27/2018] [Accepted: 07/01/2018] [Indexed: 12/27/2022]
Abstract
Bacterial plasmids constitute a wealth of shared DNA amounting to about 20% of the total prokaryotic pangenome. Plasmids replicate autonomously and control their replication by maintaining a fairly constant number of copies within a given host. Plasmids should acquire a good fitness to their hosts so that they do not constitute a genetic load. Here we review some basic concepts in plasmid biology, pertaining to the control of replication and distribution of plasmid copies among daughter cells. A particular class of plasmids is constituted by those that replicate by the rolling circle mode (rolling circle-replicating [RCR]-plasmids). They are small double-stranded DNA molecules, with a rather high number of copies in the original host. RCR-plasmids control their replication by means of a small short-lived antisense RNA, alone or in combination with a plasmid-encoded transcriptional repressor protein. Two plasmid prototypes have been studied in depth, namely the staphylococcal plasmid pT181 and the streptococcal plasmid pMV158, each corresponding to the two types of replication control circuits, respectively. We further discuss possible applications of the plasmid-encoded antisense RNAs and address some future directions that, in our opinion, should be pursued in the study of these small molecules. This article is categorized under: Regulatory RNAs/RNAi/Riboswitches > Regulatory RNAs RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems.
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Affiliation(s)
- Radoslaw Pluta
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology in Warsaw, Warsaw, Poland
| | - Manuel Espinosa
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu, Madrid, Spain
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Folding a viral peptide in different membrane environments: pathway and sampling analyses. J Biol Phys 2018; 44:195-209. [PMID: 29644513 DOI: 10.1007/s10867-018-9490-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 03/16/2018] [Indexed: 10/17/2022] Open
Abstract
Flock House virus (FHV) is a well-characterized model system to study infection mechanisms in non-enveloped viruses. A key stage of the infection cycle is the disruption of the endosomal membrane by a component of the FHV capsid, the membrane active γ peptide. In this study, we perform all-atom molecular dynamics simulations of the 21 N-terminal residues of the γ peptide interacting with membranes of differing compositions. We carry out umbrella sampling calculations to study the folding of the peptide to a helical state in homogenous and heterogeneous membranes consisting of neutral and anionic lipids. From the trajectory data, we evaluate folding energetics and dissect the mechanism of folding in the different membrane environments. We conclude the study by analyzing the extent of configurational sampling by performing time-lagged independent component analysis.
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