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Tam EH, Peng Y, Cheah MXY, Yan C, Xiao T. Neutralizing antibodies to block viral entry and for identification of entry inhibitors. Antiviral Res 2024; 224:105834. [PMID: 38369246 DOI: 10.1016/j.antiviral.2024.105834] [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: 10/31/2023] [Revised: 02/01/2024] [Accepted: 02/07/2024] [Indexed: 02/20/2024]
Abstract
Neutralizing antibodies (NAbs) are naturally produced by our immune system to combat viral infections. Clinically, neutralizing antibodies with potent efficacy and high specificity have been extensively used to prevent and treat a wide variety of viral infections, including Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), Human Immunodeficiency Virus (HIV), Dengue Virus (DENV) and Hepatitis B Virus (HBV). An overwhelmingly large subset of clinically effective NAbs operates by targeting viral envelope proteins to inhibit viral entry into the host cell. Binding of viral envelope protein to the host receptor is a critical rate limiting step triggering a cascade of downstream events, including endocytosis, membrane fusion and pore formation to allow viral entry. In recent years, improved structural knowledge on these processes have allowed researchers to also leverage NAbs as an indispensable tool in guiding discovery of novel antiviral entry inhibitors, providing drug candidates with high efficacy and pan-genus specificity. This review will summarize the latest progresses on the applications of NAbs as effective entry inhibitors and as important tools to develop antiviral therapeutics by high-throughput drug screenings, rational design of peptidic entry inhibitor mimicking NAbs and in silico computational modeling approaches.
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Affiliation(s)
- Ee Hong Tam
- School of Biological Sciences, Nanyang Technological University 637551, Singapore; Institute of Structural Biology, Nanyang Technological University 636921, Singapore
| | - Yu Peng
- School of Biological Sciences, Nanyang Technological University 637551, Singapore; Institute of Structural Biology, Nanyang Technological University 636921, Singapore
| | - Megan Xin Yan Cheah
- Institute of Molecular and Cell Biology, A*STAR (Agency of Science, Technology and Research) 138673, Singapore
| | - Chuan Yan
- Institute of Molecular and Cell Biology, A*STAR (Agency of Science, Technology and Research) 138673, Singapore
| | - Tianshu Xiao
- School of Biological Sciences, Nanyang Technological University 637551, Singapore; Institute of Structural Biology, Nanyang Technological University 636921, Singapore.
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2
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Perera DR, Ranadeva ND, Sirisena K, Wijesinghe KJ. Roles of NS1 Protein in Flavivirus Pathogenesis. ACS Infect Dis 2024; 10:20-56. [PMID: 38110348 DOI: 10.1021/acsinfecdis.3c00566] [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: 12/20/2023]
Abstract
Flaviviruses such as dengue, Zika, and West Nile viruses are highly concerning pathogens that pose significant risks to public health. The NS1 protein is conserved among flaviviruses and is synthesized as a part of the flavivirus polyprotein. It plays a critical role in viral replication, disease progression, and immune evasion. Post-translational modifications influence NS1's stability, secretion, antigenicity, and interactions with host factors. NS1 protein forms extensive interactions with host cellular proteins allowing it to affect vital processes such as RNA processing, gene expression regulation, and cellular homeostasis, which in turn influence viral replication, disease pathogenesis, and immune responses. NS1 acts as an immune evasion factor by delaying complement-dependent lysis of infected cells and contributes to disease pathogenesis by inducing endothelial cell damage and vascular leakage and triggering autoimmune responses. Anti-NS1 antibodies have been shown to cross-react with host endothelial cells and platelets, causing autoimmune destruction that is hypothesized to contribute to disease pathogenesis. However, in contrast, immunization of animal models with the NS1 protein confers protection against lethal challenges from flaviviruses such as dengue and Zika viruses. Understanding the multifaceted roles of NS1 in flavivirus pathogenesis is crucial for effective disease management and control. Therefore, further research into NS1 biology, including its host protein interactions and additional roles in disease pathology, is imperative for the development of strategies and therapeutics to combat flavivirus infections successfully. This Review provides an in-depth exploration of the current available knowledge on the multifaceted roles of the NS1 protein in the pathogenesis of flaviviruses.
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Affiliation(s)
- Dayangi R Perera
- Department of Chemistry, Faculty of Science, University of Colombo, Sri Lanka 00300
| | - Nadeeka D Ranadeva
- Department of Biomedical Science, Faculty of Health Sciences, KIU Campus Sri Lanka 10120
| | - Kavish Sirisena
- Department of Chemistry, Faculty of Science, University of Colombo, Sri Lanka 00300
- Section of Genetics, Institute for Research and Development in Health and Social Care, Sri Lanka 10120
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3
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Maloney BE, Carpio KL, Bilyeu AN, Saunders DRD, Park SL, Pohl AE, Ball NC, Raetz JL, Huang CY, Higgs S, Barrett ADT, Roman-Sosa G, Kenney JL, Vanlandingham DL, Huang YJS. Identification of the flavivirus conserved residues in the envelope protein hinge region for the rational design of a candidate West Nile live-attenuated vaccine. NPJ Vaccines 2023; 8:172. [PMID: 37932282 PMCID: PMC10628263 DOI: 10.1038/s41541-023-00765-0] [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: 01/30/2023] [Accepted: 10/18/2023] [Indexed: 11/08/2023] Open
Abstract
The flavivirus envelope protein is a class II fusion protein that drives flavivirus-cell membrane fusion. The membrane fusion process is triggered by the conformational change of the E protein from dimer in the virion to trimer, which involves the rearrangement of three domains, EDI, EDII, and EDIII. The movement between EDI and EDII initiates the formation of the E protein trimer. The EDI-EDII hinge region utilizes four motifs to exert the hinge effect at the interdomain region and is crucial for the membrane fusion activity of the E protein. Using West Nile virus (WNV) NY99 strain derived from an infectious clone, we investigated the role of eight flavivirus-conserved hydrophobic residues in the EDI-EDII hinge region in the conformational change of E protein from dimer to trimer and viral entry. Single mutations of the E-A54, E-I130, E-I135, E-I196, and E-Y201 residues affected infectivity. Importantly, the E-A54I and E-Y201P mutations fully attenuated the mouse neuroinvasive phenotype of WNV. The results suggest that multiple flavivirus-conserved hydrophobic residues in the EDI-EDII hinge region play a critical role in the structure-function of the E protein and some contribute to the virulence phenotype of flaviviruses as demonstrated by the attenuation of the mouse neuroinvasive phenotype of WNV. Thus, as a proof of concept, residues in the EDI-EDII hinge region are proposed targets to engineer attenuating mutations for inclusion in the rational design of candidate live-attenuated flavivirus vaccines.
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Affiliation(s)
- Bailey E Maloney
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA
- Biosecurity Research Institute, Kansas State University, Manhattan, KS, 66506, USA
| | - Kassandra L Carpio
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, 77555, USA
- Sealy Institute for Vaccine Sciences, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Ashley N Bilyeu
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA
- Biosecurity Research Institute, Kansas State University, Manhattan, KS, 66506, USA
| | - Danielle R D Saunders
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA
- Biosecurity Research Institute, Kansas State University, Manhattan, KS, 66506, USA
- Department of Biology, Dean of Faculty, United States Air Force Academy, Colorado Springs, CO, 80840, USA
| | - So Lee Park
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA
- Biosecurity Research Institute, Kansas State University, Manhattan, KS, 66506, USA
| | - Adrienne E Pohl
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA
- Biosecurity Research Institute, Kansas State University, Manhattan, KS, 66506, USA
| | - Natalia Costa Ball
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA
- Biosecurity Research Institute, Kansas State University, Manhattan, KS, 66506, USA
| | - Janae L Raetz
- Division of Vector-borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, 80521, USA
| | - Claire Y Huang
- Division of Vector-borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, 80521, USA
| | - Stephen Higgs
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA
- Biosecurity Research Institute, Kansas State University, Manhattan, KS, 66506, USA
| | - Alan D T Barrett
- Sealy Institute for Vaccine Sciences, University of Texas Medical Branch, Galveston, TX, 77555, USA
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Gleyder Roman-Sosa
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA
- Institute of Virology, University of Veterinary Medicine Hanover, Foundation, Buentewg 17, 30559, Hanover, Germany
| | - Joanie L Kenney
- Division of Vector-borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, 80521, USA
| | - Dana L Vanlandingham
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA
- Biosecurity Research Institute, Kansas State University, Manhattan, KS, 66506, USA
| | - Yan-Jang S Huang
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, 66506, USA.
- Biosecurity Research Institute, Kansas State University, Manhattan, KS, 66506, USA.
- Department of Microbiology and Immunology and SUNY Center for Vector-Borne Diseases, Institute of Global Health and Translation Science, Upstate Medical University, Syracuse, NY, 13210, USA.
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Desingu PA, Mishra S, Dindi L, Srinivasan S, Rajmani RS, Ravi V, Tamta AK, Raghu S, Murugasamy K, Pandit AS, Sundaresan NR. PARP1 inhibition protects mice against Japanese encephalitis virus infection. Cell Rep 2023; 42:113103. [PMID: 37676769 DOI: 10.1016/j.celrep.2023.113103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 05/20/2023] [Accepted: 08/22/2023] [Indexed: 09/09/2023] Open
Abstract
Japanese encephalitis (JE) is a vector-borne viral disease that causes acute encephalitis in children. Although vaccines have been developed against the JE virus (JEV), no effective antiviral therapy exists. Our study shows that inhibition of poly(ADP-ribose) polymerase 1 (PARP1), an NAD+-dependent (poly-ADP) ribosyl transferase, protects against JEV infection. Interestingly, PARP1 is critical for JEV pathogenesis in Neuro-2a cells and mice. Small molecular inhibitors of PARP1, olaparib, and 3-aminobenzamide (3-AB) significantly reduce clinical signs and viral load in the serum and brains of mice and improve survival. PARP1 inhibition confers protection against JEV infection by inhibiting autophagy. Mechanistically, upon JEV infection, PARP1 PARylates AKT and negatively affects its phosphorylation. In addition, PARP1 transcriptionally upregulates PTEN, the PIP3 phosphatase, negatively regulating AKT. PARP1-mediated AKT inactivation promotes autophagy and JEV pathogenesis by increasing the FoxO activity. Thus, our findings demonstrate PARP1 as a potential mediator of JEV pathogenesis that can be effectively targeted for treating JE.
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Affiliation(s)
- Perumal Arumugam Desingu
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru 560012, India.
| | - Sneha Mishra
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru 560012, India
| | - Lavanya Dindi
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru 560012, India
| | - Shalini Srinivasan
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru 560012, India
| | - Raju S Rajmani
- Centre for Infectious Disease Research, Indian Institute of Science, Bengaluru 560012, India
| | - Venkatraman Ravi
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru 560012, India
| | - Ankit Kumar Tamta
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru 560012, India
| | - Sukanya Raghu
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru 560012, India
| | - Krishnega Murugasamy
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru 560012, India
| | - Anwit Shriniwas Pandit
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru 560012, India
| | - Nagalingam R Sundaresan
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bengaluru 560012, India.
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5
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Lata K, Charles S, Mangala Prasad V. Advances in computational approaches to structure determination of alphaviruses and flaviviruses using cryo-electron microscopy. J Struct Biol 2023; 215:107993. [PMID: 37414374 DOI: 10.1016/j.jsb.2023.107993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 05/15/2023] [Accepted: 07/03/2023] [Indexed: 07/08/2023]
Abstract
Advancements in the field of cryo-electron microscopy (cryo-EM) have greatly contributed to our current understanding of virus structures and life cycles. In this review, we discuss the application of single particle cryo-electron microscopy (EM) for the structure elucidation of small enveloped icosahedral viruses, namely, alpha- and flaviviruses. We focus on technical advances in cryo-EM data collection, image processing, three-dimensional reconstruction, and refinement strategies for obtaining high-resolution structures of these viruses. Each of these developments enabled new insights into the alpha- and flavivirus architecture, leading to a better understanding of their biology, pathogenesis, immune response, immunogen design, and therapeutic development.
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Affiliation(s)
- Kiran Lata
- Molecular Biophysics Unit, Indian Institute of Science, Bengaluru, Karnataka 560012, India
| | - Sylvia Charles
- Molecular Biophysics Unit, Indian Institute of Science, Bengaluru, Karnataka 560012, India
| | - Vidya Mangala Prasad
- Molecular Biophysics Unit, Indian Institute of Science, Bengaluru, Karnataka 560012, India; Center for Infectious Disease Research, Indian Institute of Science, Bengaluru, Karnataka 560012, India
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6
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Adams C, Carbaugh DL, Shu B, Ng TS, Castillo IN, Bhowmik R, Segovia-Chumbez B, Puhl AC, Graham S, Diehl SA, Lazear HM, Lok SM, de Silva AM, Premkumar L. Structure and neutralization mechanism of a human antibody targeting a complex Epitope on Zika virus. PLoS Pathog 2023; 19:e1010814. [PMID: 36626401 PMCID: PMC9870165 DOI: 10.1371/journal.ppat.1010814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 01/23/2023] [Accepted: 12/05/2022] [Indexed: 01/11/2023] Open
Abstract
We currently have an incomplete understanding of why only a fraction of human antibodies that bind to flaviviruses block infection of cells. Here we define the footprint of a strongly neutralizing human monoclonal antibody (mAb G9E) with Zika virus (ZIKV) by both X-ray crystallography and cryo-electron microscopy. Flavivirus envelope (E) glycoproteins are present as homodimers on the virion surface, and G9E bound to a quaternary structure epitope spanning both E protomers forming a homodimer. As G9E mainly neutralized ZIKV by blocking a step after viral attachment to cells, we tested if the neutralization mechanism of G9E was dependent on the mAb cross-linking E molecules and blocking low-pH triggered conformational changes required for viral membrane fusion. We introduced targeted mutations to the G9E paratope to create recombinant antibodies that bound to the ZIKV envelope without cross-linking E protomers. The G9E paratope mutants that bound to a restricted epitope on one protomer poorly neutralized ZIKV compared to the wild-type mAb, demonstrating that the neutralization mechanism depended on the ability of G9E to cross-link E proteins. In cell-free low pH triggered viral fusion assay, both wild-type G9E, and epitope restricted paratope mutant G9E bound to ZIKV but only the wild-type G9E blocked fusion. We propose that, beyond antibody binding strength, the ability of human antibodies to cross-link E-proteins is a critical determinant of flavivirus neutralization potency.
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Affiliation(s)
- Cameron Adams
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Derek L. Carbaugh
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Bo Shu
- Program in Emerging Infectious Diseases, Duke-National University of Singapore Medical School, Singapore, Singapore
- Centre for Bio-Imaging Sciences, Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Thiam-Seng Ng
- Program in Emerging Infectious Diseases, Duke-National University of Singapore Medical School, Singapore, Singapore
- Centre for Bio-Imaging Sciences, Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Izabella N. Castillo
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Ryan Bhowmik
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Bruno Segovia-Chumbez
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Ana C. Puhl
- Center for Integrative Chemical Biology and Drug Discovery, Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Stephen Graham
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Sean A. Diehl
- Department of Microbiology and Molecular Genetics, University of Vermont Larner College of Medicine, Burlington, Vermont, United States of America
| | - Helen M. Lazear
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Shee-mei Lok
- Program in Emerging Infectious Diseases, Duke-National University of Singapore Medical School, Singapore, Singapore
- Centre for Bio-Imaging Sciences, Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Aravinda M. de Silva
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Lakshmanane Premkumar
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
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7
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Krishnamoorthy P, Raj AS, Kumar P, Das N, Kumar H. Host and viral non-coding RNAs in dengue pathogenesis. Rev Med Virol 2022; 32:e2360. [PMID: 35510480 DOI: 10.1002/rmv.2360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 04/15/2022] [Accepted: 04/20/2022] [Indexed: 11/10/2022]
Abstract
Dengue virus (DENV) is a mosquito-borne flavivirus that causes frequent outbreaks in tropical countries. Due to the four different serotypes and ever-mutating RNA genome, it is challenging to develop efficient therapeutics. Early diagnosis is crucial to prevent the severe form of dengue, leading to mortality. In the past decade, rapid advancement in the high throughput sequencing technologies has shed light on the crucial regulating role of non-coding RNAs (ncRNAs), also known as the "dark matter" of the genome, in various pathological processes. In addition to the human host ncRNAs like microRNAs and circular RNAs, DENV also produces ncRNAs such as subgenomic flaviviral RNAs that can modulate the virus life cycle and regulate disease outcomes. This review outlines the advances in understanding the interplay between the human host and DENV ncRNAs, their regulation of the innate immune system of the host, and the prospects of the ncRNAs in clinical applications such as dengue diagnosis and promising therapeutics.
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Affiliation(s)
- Pandikannan Krishnamoorthy
- Department of Biological Sciences, Laboratory of Immunology and Infectious Disease Biology, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal, Madhya Pradesh, India
| | - Athira S Raj
- Department of Biological Sciences, Laboratory of Immunology and Infectious Disease Biology, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal, Madhya Pradesh, India
| | - Pramod Kumar
- Department of Biological Sciences, Laboratory of Immunology and Infectious Disease Biology, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal, Madhya Pradesh, India
| | - Nilanjana Das
- Department of Biological Sciences, Laboratory of Immunology and Infectious Disease Biology, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal, Madhya Pradesh, India
| | - Himanshu Kumar
- Department of Biological Sciences, Laboratory of Immunology and Infectious Disease Biology, Indian Institute of Science Education and Research (IISER) Bhopal, Bhopal, Madhya Pradesh, India.,Laboratory of Host Defense, WPI Immunology, Frontier Research Centre, Osaka University, Osaka, Japan
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8
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Development of antiviral carbon quantum dots that target the Japanese encephalitis virus envelope protein. J Biol Chem 2022; 298:101957. [PMID: 35452675 PMCID: PMC9123278 DOI: 10.1016/j.jbc.2022.101957] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Revised: 04/06/2022] [Accepted: 04/07/2022] [Indexed: 12/23/2022] Open
Abstract
Japanese encephalitis is a mosquito-borne disease caused by the Japanese encephalitis virus (JEV) that is prevalent in Asia and the Western Pacific. Currently, there is no effective treatment for Japanese encephalitis. Curcumin (Cur) is a compound extracted from the roots of Curcuma longa, and many studies have reported its antiviral and anti-inflammatory activities. However, the high cytotoxicity and very low solubility of Cur limit its biomedical applications. In this study, Cur carbon quantum dots (Cur-CQDs) were synthesized by mild pyrolysis-induced polymerization and carbonization, leading to higher water solubility and lower cytotoxicity, as well as superior antiviral activity against JEV infection. We found that Cur-CQDs effectively bound to the E protein of JEV, preventing viral entry into the host cells. In addition, after continued treatment of JEV with Cur-CQDs, a mutant strain of JEV was evolved that did not support binding of Cur-CQDs to the JEV envelope. Using transmission electron microscopy, biolayer interferometry, and molecular docking analysis, we revealed that the S123R and K312R mutations in the E protein play a key role in binding Cur-CQDs. The S123 and K312 residues are located in structural domains II and III of the E protein, respectively, and are responsible for binding to receptors on and fusing with the cell membrane. Taken together, our results suggest that the E protein of flaviviruses represents a potential target for the development of CQD-based inhibitors to prevent or treat viral infections.
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9
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Fishburn AT, Pham OH, Kenaston MW, Beesabathuni NS, Shah PS. Let's Get Physical: Flavivirus-Host Protein-Protein Interactions in Replication and Pathogenesis. Front Microbiol 2022; 13:847588. [PMID: 35308381 PMCID: PMC8928165 DOI: 10.3389/fmicb.2022.847588] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 01/31/2022] [Indexed: 12/23/2022] Open
Abstract
Flaviviruses comprise a genus of viruses that pose a significant burden on human health worldwide. Transmission by both mosquito and tick vectors, and broad host tropism contribute to the presence of flaviviruses globally. Like all viruses, they require utilization of host molecular machinery to facilitate their replication through physical interactions. Their RNA genomes are translated using host ribosomes, synthesizing viral proteins that cooperate with each other and host proteins to reshape the host cell into a factory for virus replication. Thus, dissecting the physical interactions between viral proteins and their host protein targets is essential in our comprehension of how flaviviruses replicate and how they alter host cell behavior. Beyond replication, even single interactions can contribute to immune evasion and pathogenesis, providing potential avenues for therapeutic intervention. Here, we review protein interactions between flavivirus and host proteins that contribute to virus replication, immune evasion, and disease.
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Affiliation(s)
- Adam T Fishburn
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA, United States
| | - Oanh H Pham
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA, United States
| | - Matthew W Kenaston
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA, United States
| | - Nitin S Beesabathuni
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA, United States.,Department of Chemical Engineering, University of California, Davis, Davis, CA, United States
| | - Priya S Shah
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, CA, United States.,Department of Chemical Engineering, University of California, Davis, Davis, CA, United States
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Agarwal N, Jaiswal N, Gulati K, Gangele K, Nagar N, Kumar D, Poluri KM. Molecular Insights into Conformational Heterogeneity and Enhanced Structural Integrity of Helicobacter pylori DNA Binding Protein Hup at Low pH. Biochemistry 2021; 60:3236-3252. [PMID: 34665609 DOI: 10.1021/acs.biochem.1c00395] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The summarized amalgam of internal relaxation modulations and external forces like pH, temperature, and solvent conditions determine the protein structure, stability, and function. In a free-energy landscape, although conformers are arranged in vertical hierarchy, there exist several adjacent parallel sets with conformers occupying equivalent energy cleft. Such conformational states are pre-requisites for the functioning of proteins that have oscillating environmental conditions. As these conformational changes have utterly small re-arrangements, nuclear magnetic resonance (NMR) spectroscopy is unique in elucidating the structure-dynamics-stability-function relationships for such conformations. Helicobacter pylori survives and causes gastric cancer at extremely low pH also. However, least is known as to how the genome of the pathogen is protected from reactive oxygen species (ROS) scavenging in the gut at low pH under acidic stress. In the current study, biophysical characteristics of H. pylori DNA binding protein (Hup) have been elucidated at pH 2 using a combination of circular dichroism, fluorescence, NMR spectroscopy, and molecular dynamics simulations. Interestingly, the protein was found to have conserved structural features, differential backbone dynamics, enhanced stability, and DNA binding ability at low pH as well. In summary, the study suggests the partaking of Hup protein even at low pH in DNA protection for maintaining the genome integrity.
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Affiliation(s)
- Nipanshu Agarwal
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667 Uttarakhand, India
| | - Nancy Jaiswal
- Centre of Biomedical Research, SGPGIMS Campus, Lucknow 226014, India
| | - Khushboo Gulati
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667 Uttarakhand, India
| | - Krishnakant Gangele
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667 Uttarakhand, India
| | - Nupur Nagar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667 Uttarakhand, India
| | - Dinesh Kumar
- Centre of Biomedical Research, SGPGIMS Campus, Lucknow 226014, India
| | - Krishna Mohan Poluri
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667 Uttarakhand, India.,Centre for Nanotechnology, Indian Institute of Technology Roorkee, Roorkee 247667 Uttarakhand, India
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11
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Tuchynskaya KK, Fomina AD, Nikitin NA, Illarionova VV, Volok VP, Kozlovskaya LI, Rogova AA, Vasilenko DA, Averina EB, Osolodkin DI, Karganova GG. Effect of immature tick-borne encephalitis virus particles on antiviral activity of 5-aminoisoxazole-3-carboxylic acid adamantylmethyl esters. J Gen Virol 2021; 102. [PMID: 34546870 DOI: 10.1099/jgv.0.001658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Tick-borne encephalitis virus (TBEV), a member of the genus Flavivirus, is common in Europe and Asia and causes a severe disease of the central nervous system. A promising approach in the development of therapy for TBEV infection is the search for small molecule antivirals targeting the flavivirus envelope protein E, particularly its β-n-octyl-d-glucoside binding pocket (β-OG pocket). However, experimental studies of candidate antivirals may be complicated by varying amounts and different forms of the protein E in the virus samples. Viral particles with different conformations and arrangements of the protein E are produced during the replication cycle of flaviviruses, including mature, partially mature, and immature forms, as well as subviral particles lacking genomic RNA. The immature forms are known to be abundant in the viral population. We obtained immature virion preparations of TBEV, characterized them by RT-qPCR, and assessed in vivo and in vitro infectivity of the residual mature virions in the immature virus samples. Analysis of the β-OG pocket structure on the immature virions confirmed the possibility of binding of adamantylmethyl esters of 5-aminoisoxazole-3-carboxylic acid in the pocket. We demonstrated that the antiviral activity of these compounds in plaque reduction assay is significantly reduced in the presence of immature TBEV particles.
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Affiliation(s)
- Ksenia K Tuchynskaya
- FSASI "Chumakov FSC R&D IBP RAS" (Institute of Poliomyelitis), Moscow 108819, Russia
| | - Anastasiia D Fomina
- FSASI "Chumakov FSC R&D IBP RAS" (Institute of Poliomyelitis), Moscow 108819, Russia.,Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Nikolai A Nikitin
- Department of Biology, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Viktoria V Illarionova
- FSASI "Chumakov FSC R&D IBP RAS" (Institute of Poliomyelitis), Moscow 108819, Russia.,Department of Biology, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Viktor P Volok
- FSASI "Chumakov FSC R&D IBP RAS" (Institute of Poliomyelitis), Moscow 108819, Russia.,Department of Biology, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Liubov I Kozlovskaya
- FSASI "Chumakov FSC R&D IBP RAS" (Institute of Poliomyelitis), Moscow 108819, Russia.,Institute of Translational Medicine and Biotechnology, Sechenov First Moscow State Medical University, Moscow 119435, Russia
| | - Anastasia A Rogova
- FSASI "Chumakov FSC R&D IBP RAS" (Institute of Poliomyelitis), Moscow 108819, Russia
| | - Dmitry A Vasilenko
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Elena B Averina
- Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Dmitry I Osolodkin
- FSASI "Chumakov FSC R&D IBP RAS" (Institute of Poliomyelitis), Moscow 108819, Russia.,Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia.,Institute of Translational Medicine and Biotechnology, Sechenov First Moscow State Medical University, Moscow 119435, Russia
| | - Galina G Karganova
- FSASI "Chumakov FSC R&D IBP RAS" (Institute of Poliomyelitis), Moscow 108819, Russia.,Institute of Translational Medicine and Biotechnology, Sechenov First Moscow State Medical University, Moscow 119435, Russia
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12
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Molecular Insights into the Flavivirus Replication Complex. Viruses 2021; 13:v13060956. [PMID: 34064113 PMCID: PMC8224304 DOI: 10.3390/v13060956] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Revised: 05/17/2021] [Accepted: 05/17/2021] [Indexed: 12/11/2022] Open
Abstract
Flaviviruses are vector-borne RNA viruses, many of which are clinically relevant human viral pathogens, such as dengue, Zika, Japanese encephalitis, West Nile and yellow fever viruses. Millions of people are infected with these viruses around the world each year. Vaccines are only available for some members of this large virus family, and there are no effective antiviral drugs to treat flavivirus infections. The unmet need for vaccines and therapies against these flaviviral infections drives research towards a better understanding of the epidemiology, biology and immunology of flaviviruses. In this review, we discuss the basic biology of the flavivirus replication process and focus on the molecular aspects of viral genome replication. Within the virus-induced intracellular membranous compartments, flaviviral RNA genome replication takes place, starting from viral poly protein expression and processing to the assembly of the virus RNA replication complex, followed by the delivery of the progeny viral RNA to the viral particle assembly sites. We attempt to update the latest understanding of the key molecular events during this process and highlight knowledge gaps for future studies.
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13
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Dey D, Poudyal S, Rehman A, Hasan SS. Structural and biochemical insights into flavivirus proteins. Virus Res 2021; 296:198343. [PMID: 33607183 DOI: 10.1016/j.virusres.2021.198343] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 02/10/2021] [Accepted: 02/11/2021] [Indexed: 01/01/2023]
Abstract
Flaviviruses are the fastest spreading arthropod-borne viruses that cause severe symptoms such as hepatitis, hemorrhagic fever, encephalitis, and congenital deformities. Nearly 40 % of the entire human population is at risk of flavivirus epidemics. Yet, effective vaccination is restricted only to a few flaviviruses such as yellow fever and Japanese encephalitis viruses, and most recently for select cases of dengue virus infections. Despite the global spread of dengue virus, and emergence of new threats such as Zika virus and a new genotype of Japanese encephalitis virus, insights into flavivirus targets for potentially broad-spectrum vaccination are limited. In this review article, we highlight biochemical and structural differences in flavivirus proteins critical for virus assembly and host interactions. A comparative sequence analysis of pH-responsive properties of viral structural proteins identifies trends in conservation of complementary acidic-basic character between interacting viral structural proteins. This is highly relevant to the understanding of pH-sensitive differences in virus assembly in organelles such as neutral ER and acidic Golgi. Surface residues in viral interfaces identified by structural approaches are shown to demonstrate partial conservation, further reinforcing virus-specificity in assembly and interactions with host proteins. A comparative analysis of epitope conservation in emerging flaviviruses identifies therapeutic antibody candidates that have potential as broad spectrum anti-virals, thus providing a path towards development of vaccines.
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Affiliation(s)
- Debajit Dey
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 N. Greene Street, Baltimore MD 21201, USA
| | - Shishir Poudyal
- Department of Biological Sciences, Purdue University, 915 W. State Street, West Lafayette IN 47907, USA
| | - Asma Rehman
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 N. Greene Street, Baltimore MD 21201, USA
| | - S Saif Hasan
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 N. Greene Street, Baltimore MD 21201, USA; University of Maryland Marlene and Stewart Greenebaum Cancer Center, University of Maryland Medical Center, 22. S. Greene St. Baltimore MD 21201, USA; Center for Biomolecular Therapeutics, University of Maryland School of Medicine, 9600 Gudelsky Drive, Rockville MD 20850, USA.
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14
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Wollner CJ, Richner JM. mRNA Vaccines against Flaviviruses. Vaccines (Basel) 2021; 9:148. [PMID: 33673131 PMCID: PMC7918459 DOI: 10.3390/vaccines9020148] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 12/15/2022] Open
Abstract
Numerous vaccines have now been developed using the mRNA platform. In this approach, mRNA coding for a viral antigen is in vitro synthesized and injected into the host leading to exogenous protein expression and robust immune responses. Vaccines can be rapidly developed utilizing the mRNA platform in the face of emerging pandemics. Additionally, the mRNA coding region can be easily manipulated to test novel hypotheses in order to combat viral infections which have remained refractory to traditional vaccine approaches. Flaviviruses are a diverse family of viruses that cause widespread disease and have pandemic potential. In this review, we discuss the mRNA vaccines which have been developed against diverse flaviviruses.
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Affiliation(s)
| | - Justin M. Richner
- Department of Microbiology and Immunology, University of Illinois College of Medicine, Chicago, IL 60612, USA;
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15
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Westlake D, Bielefeldt-Ohmann H, Prow NA, Hall RA. Novel Flavivirus Attenuation Markers Identified in the Envelope Protein of Alfuy Virus. Viruses 2021; 13:v13020147. [PMID: 33498300 PMCID: PMC7909262 DOI: 10.3390/v13020147] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/12/2021] [Accepted: 01/14/2021] [Indexed: 11/16/2022] Open
Abstract
Alfuy (ALFV) is an attenuated flavivirus related to the Murray Valley encephalitis virus (MVEV). We previously identified markers of attenuation in the envelope (E) protein of the prototype strain (ALFV3929), including the hinge region (E273-277) and lack of glycosylation at E154-156. To further determine the mechanisms of attenuation we assessed ALFV3929 binding to glycosaminoglycans (GAG), a known mechanism of flaviviruses attenuation. Indeed, ALFV3929 exhibited reduced binding to GAG-rich cells in the presence of heparin; however, low-passage ALFV isolates were relatively unaffected. Sequence comparisons between ALFV strains and structural modelling incriminated a positively-charged residue (K327) in ALFV3929 as a GAG-binding motif. Substitution of this residue to the corresponding uncharged residue in MVEV (L), using a previously described chimeric virus containing the prM & E genes of ALFV3929 in the backbone of MVEV (MVEV/ALFV-prME), confirmed a role for K327 in enhanced GAG binding. When the wild type residues at E327, E273-277 and E154-156 of ALFV3929 were replaced with the corresponding residues from virulent MVEV, it revealed each motif contributed to attenuation of ALFV3929, with the E327/E273-277 combination most dominant. These data demonstrate that attenuation of ALFV3929 is multifactorial and provide new insights for the rational design of attenuated flavivirus vaccines.
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Affiliation(s)
- Daniel Westlake
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD 4072, Australia; (D.W.); (H.B.-O.)
| | - Helle Bielefeldt-Ohmann
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD 4072, Australia; (D.W.); (H.B.-O.)
- Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, QLD 4072, Australia
- School of Veterinary Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Natalie A. Prow
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD 4072, Australia; (D.W.); (H.B.-O.)
- Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, QLD 4072, Australia
- Experimental Therapeutics Laboratory, School of Clinical and Health Sciences, University of South Australia Cancer Research Institute, Adelaide, SA 5000, Australia
- Correspondence: (N.A.P.); (R.A.H.)
| | - Roy A. Hall
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD 4072, Australia; (D.W.); (H.B.-O.)
- Australian Infectious Diseases Research Centre, The University of Queensland, St. Lucia, QLD 4072, Australia
- Correspondence: (N.A.P.); (R.A.H.)
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16
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Park A, Graceffa O, Rawle RJ. Kinetic Modeling of West Nile Virus Fusion Indicates an Off-Pathway State. ACS Infect Dis 2020; 6:3260-3268. [PMID: 33201665 DOI: 10.1021/acsinfecdis.0c00637] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
West Nile virus (WNV) is a prominent mosquito-borne flavivirus that causes febrile illness in humans. To infect host cells, WNV virions first bind to plasma membrane receptors, then initiate membrane fusion following endocytosis. The viral transmembrane E protein, triggered by endosomal pH, catalyzes fusion while undergoing a dimer-to-trimer transition. Previously, single-particle WNV fusion data was interrogated with a stochastic cellular automaton simulation, which modeled the E proteins during the fusion process. The results supported a linear fusion mechanism, with E protein trimerization being rate-limiting. Here, we present corrections to the previous simulation, and apply them to the WNV fusion data. We observe that a linear mechanism is no longer sufficient to fit the data. Instead, an off-pathway state is necessary; these results are corroborated by per virus chemical kinetics modeling. When compared with a similar Zika virus fusion model, this suggests that off-pathway fusion mechanisms may characterize flaviviruses more broadly.
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Affiliation(s)
- Abraham Park
- Department of Chemistry, Williams College, Williamstown, Massachusetts 01267, United States
| | - Olivia Graceffa
- Department of Chemistry, Williams College, Williamstown, Massachusetts 01267, United States
| | - Robert J. Rawle
- Department of Chemistry, Williams College, Williamstown, Massachusetts 01267, United States
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17
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Medits I, Vaney M, Rouvinski A, Rey M, Chamot‐Rooke J, Rey FA, Heinz FX, Stiasny K. Extensive flavivirus E trimer breathing accompanies stem zippering of the post-fusion hairpin. EMBO Rep 2020; 21:e50069. [PMID: 32484292 PMCID: PMC7403712 DOI: 10.15252/embr.202050069] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 05/11/2020] [Accepted: 05/13/2020] [Indexed: 12/23/2022] Open
Abstract
Flaviviruses enter cells by fusion with endosomal membranes through a rearrangement of the envelope protein E, a class II membrane fusion protein, into fusogenic trimers. The rod-like E subunits bend into "hairpins" to bring the fusion loops next to the C-terminal transmembrane (TM) anchors, with the TM-proximal "stem" element zippering the E trimer to force apposition of the membranes. The structure of the complete class II trimeric hairpin is known for phleboviruses but not for flaviviruses, for which the stem is only partially resolved. Here, we performed comparative analyses of E-protein trimers from the tick-borne encephalitis flavivirus with sequential stem truncations. Our thermostability and antibody-binding data suggest that the stem "zipper" ends at a characteristic flavivirus conserved sequence (CS) that cloaks the fusion loops, with the downstream segment not contributing to trimer stability. We further identified a highly dynamic behavior of E trimers C-terminally truncated upstream the CS, which, unlike fully stem-zippered trimers, undergo rapid deuterium exchange at the trimer interface. These results thus identify important "breathing" intermediates in the E-protein-driven membrane fusion process.
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Affiliation(s)
- Iris Medits
- Center for VirologyMedical University of ViennaViennaAustria
| | | | - Alexander Rouvinski
- Unité de Virologie StructuraleInstitut PasteurCNRS UMR 3569 VirologieParisFrance
- Present address:
Department of Microbiology and Molecular GeneticsInstitute for Medical Research Israel‐CanadaThe Kuvin Center for the Study of Infectious and Tropical DiseasesThe Hebrew University of JerusalemJerusalemIsrael
| | - Martial Rey
- Unité de Spectrométrie de Masse pour la BiologieInstitut PasteurCNRS USR 2000ParisFrance
| | - Julia Chamot‐Rooke
- Unité de Spectrométrie de Masse pour la BiologieInstitut PasteurCNRS USR 2000ParisFrance
| | - Felix A Rey
- Unité de Virologie StructuraleInstitut PasteurCNRS UMR 3569 VirologieParisFrance
| | - Franz X Heinz
- Center for VirologyMedical University of ViennaViennaAustria
| | - Karin Stiasny
- Center for VirologyMedical University of ViennaViennaAustria
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18
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Malafa S, Medits I, Aberle JH, Aberle SW, Haslwanter D, Tsouchnikas G, Wölfel S, Huber KL, Percivalle E, Cherpillod P, Thaler M, Roßbacher L, Kundi M, Heinz FX, Stiasny K. Impact of flavivirus vaccine-induced immunity on primary Zika virus antibody response in humans. PLoS Negl Trop Dis 2020; 14:e0008034. [PMID: 32017766 PMCID: PMC7021315 DOI: 10.1371/journal.pntd.0008034] [Citation(s) in RCA: 14] [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: 09/11/2019] [Revised: 02/14/2020] [Accepted: 01/07/2020] [Indexed: 12/30/2022] Open
Abstract
Background Zika virus has recently spread to South- and Central America, causing congenital birth defects and neurological complications. Many people at risk are flavivirus pre-immune due to prior infections with other flaviviruses (e.g. dengue virus) or flavivirus vaccinations. Since pre-existing cross-reactive immunity can potentially modulate antibody responses to Zika virus infection and may affect the outcome of disease, we analyzed fine-specificity as well as virus-neutralizing and infection-enhancing activities of antibodies induced by a primary Zika virus infection in flavivirus-naïve as well as yellow fever- and/or tick-borne encephalitis-vaccinated individuals. Methodology Antibodies in sera from convalescent Zika patients with and without vaccine-induced immunity were assessed by ELISA with respect to Zika virus-specificity and flavivirus cross-reactivity. Functional analyses included virus neutralization and infection-enhancement. The contribution of IgM and cross-reactive antibodies to these properties was determined by depletion experiments. Principal findings Pre-existing flavivirus immunity had a strong influence on the antibody response in primary Zika virus infections, resulting in higher titers of broadly flavivirus cross-reactive antibodies and slightly lower levels of Zika virus-specific IgM. Antibody-dependent enhancement (ADE) of Zika virus was mediated by sub-neutralizing concentrations of specific IgG but not by cross-reactive antibodies. This effect was potently counteracted by the presence of neutralizing IgM. Broadly cross-reactive antibodies were able to both neutralize and enhance infection of dengue virus but not Zika virus, indicating a different exposure of conserved sequence elements in the two viruses. Conclusions Our data point to an important role of flavivirus-specific IgM during the transient early stages of infection, by contributing substantially to neutralization and by counteracting ADE. In addition, our results highlight structural differences between strains of Zika and dengue viruses that are used for analyzing infection-enhancement by cross-reactive antibodies. These findings underscore the possible impact of specific antibody patterns on flavivirus disease and vaccination efficacy. The explosive spread of Zika virus, a flavivirus, to South- and Central America underscores the potential threat of newly emerging arthropod-borne viruses. Zika virus infection can cause congenital birth defects and neurological complications. Many people at risk are flavivirus pre-immune because of prior infections with other flaviviruses (e.g. dengue virus, which co-circulates in Zika outbreak regions) or vaccinations (e.g. against yellow fever or tick-borne encephalitis) and have non-protective cross-reactive antibodies at the time of infection. Since pre-existing immunity can modulate the specificity and functional activity of antibody responses, and cross-reactive antibodies have been implicated in disease enhancement, we compared the specificities of serum samples from flavivirus-naïve and vaccinated individuals after primary Zika virus infections. Prior immunity led to a strong booster of cross-reactive antibodies that did not neutralize Zika virus. Importantly, we could also show that newly formed IgM antibodies contributed significantly to virus neutralization and prevented infection enhancement by other antibodies. Our data thus show how pre-existing cross-reactive immunities can alter the specificities and functional activities of antibody responses in flavivirus infections, which may affect flavivirus-induced disease and the efficacy of vaccinations.
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Affiliation(s)
- Stefan Malafa
- Center for Virology, Medical University of Vienna, Vienna, Austria
| | - Iris Medits
- Center for Virology, Medical University of Vienna, Vienna, Austria
| | - Judith H. Aberle
- Center for Virology, Medical University of Vienna, Vienna, Austria
| | | | | | | | - Silke Wölfel
- Bundeswehr Institute of Microbiology, Munich, Germany; Center of Infection Research (DZIF) Partner, Munich, Germany
| | - Kristina L. Huber
- Division of Infectious Diseases and Tropical Medicine, Ludwig Maximilian University (LMU), Munich, Germany
| | - Elena Percivalle
- Molecular Virology Unit, Microbiology and Virology Department, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Pascal Cherpillod
- Laboratory of Virology, Laboratory Medicine Division, Geneva University Hospitals, Geneva, Switzerland
| | - Melissa Thaler
- Center for Virology, Medical University of Vienna, Vienna, Austria
| | - Lena Roßbacher
- Center for Virology, Medical University of Vienna, Vienna, Austria
| | - Michael Kundi
- Center for Public Health, Medical University of Vienna, Vienna, Austria
| | - Franz X. Heinz
- Center for Virology, Medical University of Vienna, Vienna, Austria
- * E-mail: (FXH); (KS)
| | - Karin Stiasny
- Center for Virology, Medical University of Vienna, Vienna, Austria
- * E-mail: (FXH); (KS)
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19
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Koblischke M, Spitzer FS, Florian DM, Aberle SW, Malafa S, Fae I, Cassaniti I, Jungbauer C, Knapp B, Laferl H, Fischer G, Baldanti F, Stiasny K, Heinz FX, Aberle JH. CD4 T Cell Determinants in West Nile Virus Disease and Asymptomatic Infection. Front Immunol 2020; 11:16. [PMID: 32038660 PMCID: PMC6989424 DOI: 10.3389/fimmu.2020.00016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 01/07/2020] [Indexed: 12/30/2022] Open
Abstract
West Nile (WN) virus infection of humans is frequently asymptomatic, but can also lead to WN fever or neuroinvasive disease. CD4 T cells and B cells are critical in the defense against WN virus, and neutralizing antibodies, which are directed against the viral glycoprotein E, are an accepted correlate of protection. For the efficient production of these antibodies, B cells interact directly with CD4 helper T cells that recognize peptides from E or the two other structural proteins (capsid-C and membrane-prM/M) of the virus. However, the specific protein sites yielding such helper epitopes remain unknown. Here, we explored the CD4 T cell response in humans after WN virus infection using a comprehensive library of overlapping peptides covering all three structural proteins. By measuring T cell responses in 29 individuals with either WN virus disease or asymptomatic infection, we showed that CD4 T cells focus on peptides in specific structural elements of C and at the exposed surface of the pre- and postfusion forms of the E protein. Our data indicate that these immunodominant epitopes are recognized in the context of multiple different HLA molecules. Furthermore, we observed that immunodominant antigen regions are structurally conserved and similarly targeted in other mosquito-borne flaviviruses, including dengue, yellow fever, and Zika viruses. Together, these findings indicate a strong impact of virion protein structure on epitope selection and antigenicity, which is an important issue to consider in future vaccine design.
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Affiliation(s)
| | | | - David M Florian
- Center for Virology, Medical University of Vienna, Vienna, Austria
| | - Stephan W Aberle
- Center for Virology, Medical University of Vienna, Vienna, Austria
| | - Stefan Malafa
- Center for Virology, Medical University of Vienna, Vienna, Austria
| | - Ingrid Fae
- Department of Blood Group Serology and Transfusion Medicine, Medical University of Vienna, Vienna, Austria
| | - Irene Cassaniti
- Molecular Virology Unit, Microbiology and Virology Department, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy.,Department of Clinical, Surgical, Diagnostic and Pediatric Sciences, University of Pavia, Pavia, Italy
| | - Christof Jungbauer
- Blood Service for Vienna, Lower Austria and Burgenland, Austrian Red Cross, Vienna, Austria
| | | | - Hermann Laferl
- Sozialmedizinisches Zentrum Süd, Kaiser-Franz-Josef-Spital, Vienna, Austria
| | - Gottfried Fischer
- Department of Blood Group Serology and Transfusion Medicine, Medical University of Vienna, Vienna, Austria
| | - Fausto Baldanti
- Molecular Virology Unit, Microbiology and Virology Department, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy.,Department of Clinical, Surgical, Diagnostic and Pediatric Sciences, University of Pavia, Pavia, Italy
| | - Karin Stiasny
- Center for Virology, Medical University of Vienna, Vienna, Austria
| | - Franz X Heinz
- Center for Virology, Medical University of Vienna, Vienna, Austria
| | - Judith H Aberle
- Center for Virology, Medical University of Vienna, Vienna, Austria
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20
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Rodriguez AK, Muñoz AL, Segura NA, Rangel HR, Bello F. Molecular characteristics and replication mechanism of dengue, zika and chikungunya arboviruses, and their treatments with natural extracts from plants: An updated review. EXCLI JOURNAL 2019; 18:988-1006. [PMID: 31762724 PMCID: PMC6868920 DOI: 10.17179/excli2019-1825] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 10/29/2019] [Indexed: 12/11/2022]
Abstract
Viruses transmitted by arthropods (arboviruses) are the etiological agents of several human diseases with worldwide distribution; including dengue (DENV), zika (ZIKV), yellow fever (YFV), and chikungunya (CHIKV) viruses. These viruses are especially important in tropical and subtropical regions; where, ZIKV and CHIKV are involved in epidemics worldwide, while the DENV remains as the biggest problem in public health. Factors, such as, environmental conditions promote the distribution of vectors, deficiencies in health services, and lack of effective vaccines, guarantee the presence of these vector-borne diseases. Treatment against these viral diseases is only palliative since available therapies formulated lack to demonstrate specific antiviral activity and vaccine candidates fail to demonstrate enough effectiveness. The use of natural products, as therapeutic tools, is an ancestral practice in different cultures. According to WHO 80 % of the population of some countries from Africa and Asia depend on the use of traditional medicines to deal with some diseases. Molecular characteristics of these viruses are important in determining its cellular pathogenesis, emergence, and dispersion mechanisms, as well as for the development of new antivirals and vaccines to control strategies. In this review, we summarize the current knowledge of the molecular structure and replication mechanisms of selected arboviruses, as well as their mechanism of entry into host cells, and a brief overview about the potential targets accessed to inhibit these viruses in vitro and a summary about their treatment with natural extracts from plants.
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Affiliation(s)
| | - Ana Luisa Muñoz
- Faculty of Science, Universidad Antonio Nariño (UAN), Bogotá, 110231, Colombia
| | - Nidya Alexandra Segura
- Faculty of Science, Universidad Pedagógica y Tecnológica de Colombia, Tunja 150003, Colombia
| | - Héctor Rafael Rangel
- Laboratory of Molecular Virology, Instituto Venezolano de Investigaciones Científicas, Caracas, 1204, Venezuela
| | - Felio Bello
- Faculty of Agricultural and Livestock Sciences, Program of Veterinary Medicine, Universidad de La Salle, Bogotá, 110131, Colombia
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21
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Stass R, Ng WM, Kim YC, Huiskonen JT. Structures of enveloped virions determined by cryogenic electron microscopy and tomography. Adv Virus Res 2019; 105:35-71. [PMID: 31522708 PMCID: PMC7112279 DOI: 10.1016/bs.aivir.2019.07.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Enveloped viruses enclose their genomes inside a lipid bilayer which is decorated by membrane proteins that mediate virus entry. These viruses display a wide range of sizes, morphologies and symmetries. Spherical viruses are often isometric and their envelope proteins follow icosahedral symmetry. Filamentous and pleomorphic viruses lack such global symmetry but their surface proteins may display locally ordered assemblies. Determining the structures of enveloped viruses, including the envelope proteins and their protein-protein interactions on the viral surface, is of paramount importance. These structures can reveal how the virions are assembled and released by budding from the infected host cell, how the progeny virions infect new cells by membrane fusion, and how antibodies bind surface epitopes to block infection. In this chapter, we discuss the uses of cryogenic electron microscopy (cryo-EM) in elucidating structures of enveloped virions. Starting from a detailed outline of data collection and processing strategies, we highlight how cryo-EM has been successfully utilized to provide unique insights into enveloped virus entry, assembly, and neutralization.
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Affiliation(s)
- Robert Stass
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Weng M Ng
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Young Chan Kim
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Juha T Huiskonen
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom; Helsinki Institute of Life Science HiLIFE and Research Programme in Molecular and Integrative Biosciences, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.
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22
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Rinkenberger N, Schoggins JW. Comparative analysis of viral entry for Asian and African lineages of Zika virus. Virology 2019; 533:59-67. [PMID: 31112915 DOI: 10.1016/j.virol.2019.04.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 04/20/2019] [Accepted: 04/22/2019] [Indexed: 12/16/2022]
Abstract
Zika virus (ZIKV) is an emerging pathogen with global health and economic impacts. ZIKV circulates as two major lineages, Asian or African. The Asian lineage has recently been associated with significant disease in humans. Numerous studies have revealed differences between African and Asian ZIKV strains with respect to cellular infectivity, pathogenesis, and immune activation. Less is known about the mechanism of ZIKV entry and whether viral entry differs between strains. Here, we characterized ZIKV entry with two Asian and two African strains. All viruses exhibited a requirement for clathrin-mediated endocytosis and Rab5a function. Additionally, all ZIKV strains tested were sensitive to pH in the range of 6.5-6.1 and were reliant on endosomal acidification for infection. Finally, we provide direct evidence that ZIKV primarily fuses with late endosomes. These findings contribute new insight into the ZIKV entry process and suggest that divergent ZIKV strains enter cells in a highly conserved manner.
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Affiliation(s)
- Nicholas Rinkenberger
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - John W Schoggins
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
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23
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Li PC, Jang J, Hsia CY, Groomes PV, Lian W, de Wispelaere M, Pitts JD, Wang J, Kwiatkowski N, Gray NS, Yang PL. Small Molecules Targeting the Flavivirus E Protein with Broad-Spectrum Activity and Antiviral Efficacy in Vivo. ACS Infect Dis 2019; 5:460-472. [PMID: 30608640 DOI: 10.1021/acsinfecdis.8b00322] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Vaccines and antivirals to combat dengue, Zika, and other flavivirus pathogens present a major, unmet medical need. Vaccine development has been severely challenged by the antigenic diversity of these viruses and the propensity of non-neutralizing, cross-reactive antibodies to facilitate cellular infection and increase disease severity. As an alternative, direct-acting antivirals targeting the flavivirus envelope protein, E, have the potential to act via an analogous mode of action without the risk of antibody-dependent enhancement of infection and disease. We previously discovered that structurally diverse small molecule inhibitors of the dengue virus E protein exhibit varying levels of antiviral activity against other flaviviruses in cell culture. Here, we demonstrate that the broad-spectrum activity of several cyanohydrazones against dengue, Zika, and Japanese encephalitis viruses is due to specific inhibition of E-mediated membrane fusion during viral entry and provide proof of concept for pharmacological inhibition of E as an antiviral strategy in vivo.
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Affiliation(s)
- Pi-Chun Li
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 360 Longwood Avenue, Boston, Massachusetts 02215, United States
- Department of Cancer Biology, Dana-Farber Cancer Institute, 360 Longwood Avenue, Boston, Massachusetts 02215, United States
| | - Jaebong Jang
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 360 Longwood Avenue, Boston, Massachusetts 02215, United States
- Department of Cancer Biology, Dana-Farber Cancer Institute, 360 Longwood Avenue, Boston, Massachusetts 02215, United States
| | - Chih-Yun Hsia
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
| | - Patrice V. Groomes
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
| | - Wenlong Lian
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
| | - Melissanne de Wispelaere
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
| | - Jared D. Pitts
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
| | - Jinhua Wang
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 360 Longwood Avenue, Boston, Massachusetts 02215, United States
- Department of Cancer Biology, Dana-Farber Cancer Institute, 360 Longwood Avenue, Boston, Massachusetts 02215, United States
| | - Nicholas Kwiatkowski
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 360 Longwood Avenue, Boston, Massachusetts 02215, United States
- Department of Cancer Biology, Dana-Farber Cancer Institute, 360 Longwood Avenue, Boston, Massachusetts 02215, United States
| | - Nathanael S. Gray
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 360 Longwood Avenue, Boston, Massachusetts 02215, United States
- Department of Cancer Biology, Dana-Farber Cancer Institute, 360 Longwood Avenue, Boston, Massachusetts 02215, United States
| | - Priscilla L. Yang
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
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24
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Sommer M, Sutter M, Gupta S, Kirst H, Turmo A, Lechno-Yossef S, Burton RL, Saechao C, Sloan NB, Cheng X, Chan LJG, Petzold CJ, Fuentes-Cabrera M, Ralston CY, Kerfeld CA. Heterohexamers Formed by CcmK3 and CcmK4 Increase the Complexity of Beta Carboxysome Shells. PLANT PHYSIOLOGY 2019; 179:156-167. [PMID: 30389783 PMCID: PMC6324227 DOI: 10.1104/pp.18.01190] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 10/26/2018] [Indexed: 05/10/2023]
Abstract
Bacterial microcompartments (BMCs) encapsulate enzymes within a selectively permeable, proteinaceous shell. Carboxysomes are BMCs containing ribulose-1,5-bisphosphate carboxylase oxygenase and carbonic anhydrase that enhance carbon dioxide fixation. The carboxysome shell consists of three structurally characterized protein types, each named after the oligomer they form: BMC-H (hexamer), BMC-P (pentamer), and BMC-T (trimer). These three protein types form cyclic homooligomers with pores at the center of symmetry that enable metabolite transport across the shell. Carboxysome shells contain multiple BMC-H paralogs, each with distinctly conserved residues surrounding the pore, which are assumed to be associated with specific metabolites. We studied the regulation of β-carboxysome shell composition by investigating the BMC-H genes ccmK3 and ccmK4 situated in a locus remote from other carboxysome genes. We made single and double deletion mutants of ccmK3 and ccmK4 in Synechococcus elongatus PCC7942 and show that, unlike CcmK3, CcmK4 is necessary for optimal growth. In contrast to other CcmK proteins, CcmK3 does not form homohexamers; instead CcmK3 forms heterohexamers with CcmK4 with a 1:2 stoichiometry. The CcmK3-CcmK4 heterohexamers form stacked dodecamers in a pH-dependent manner. Our results indicate that CcmK3-CcmK4 heterohexamers potentially expand the range of permeability properties of metabolite channels in carboxysome shells. Moreover, the observed facultative formation of dodecamers in solution suggests that carboxysome shell permeability may be dynamically attenuated by "capping" facet-embedded hexamers with a second hexamer. Because β-carboxysomes are obligately expressed, heterohexamer formation and capping could provide a rapid and reversible means to alter metabolite flux across the shell in response to environmental/growth conditions.
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Affiliation(s)
- Manuel Sommer
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Markus Sutter
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
- Michigan State University-U.S. Department of Energy Plant Research Laboratory and Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Sayan Gupta
- Michigan State University-U.S. Department of Energy Plant Research Laboratory and Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Henning Kirst
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
- Michigan State University-U.S. Department of Energy Plant Research Laboratory and Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Aiko Turmo
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Sigal Lechno-Yossef
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Rodney L Burton
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Christine Saechao
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720
- Michigan State University-U.S. Department of Energy Plant Research Laboratory and Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Nancy B Sloan
- Michigan State University-U.S. Department of Energy Plant Research Laboratory and Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Xiaolin Cheng
- Division of Medicinal Chemistry and Pharmacognosy and Biophysics Graduate Program, Ohio State University, Columbus, Ohio 43210
| | - Leanne-Jade G Chan
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Christopher J Petzold
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Miguel Fuentes-Cabrera
- Center for Nanophase Materials Sciences and Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennesse 37831
| | - Corie Y Ralston
- Michigan State University-U.S. Department of Energy Plant Research Laboratory and Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Cheryl A Kerfeld
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
- Michigan State University-U.S. Department of Energy Plant Research Laboratory and Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
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25
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Klitting R, Fischer C, Drexler JF, Gould EA, Roiz D, Paupy C, de Lamballerie X. What Does the Future Hold for Yellow Fever Virus? (II). Genes (Basel) 2018; 9:E425. [PMID: 30134625 PMCID: PMC6162518 DOI: 10.3390/genes9090425] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 08/13/2018] [Accepted: 08/16/2018] [Indexed: 02/06/2023] Open
Abstract
As revealed by the recent resurgence of yellow fever virus (YFV) activity in the tropical regions of Africa and South America, YFV control measures need urgent rethinking. Over the last decade, most reported outbreaks occurred in, or eventually reached, areas with low vaccination coverage but that are suitable for virus transmission, with an unprecedented risk of expansion to densely populated territories in Africa, South America and Asia. As reflected in the World Health Organization's initiative launched in 2017, it is high time to strengthen epidemiological surveillance to monitor accurately viral dissemination, and redefine vaccination recommendation areas. Vector-control and immunisation measures need to be adapted and vaccine manufacturing must be reconciled with an increasing demand. We will have to face more yellow fever (YF) cases in the upcoming years. Hence, improving disease management through the development of efficient treatments will prove most beneficial. Undoubtedly, these developments will require in-depth descriptions of YFV biology at molecular, physiological and ecological levels. This second section of a two-part review describes the current state of knowledge and gaps regarding the molecular biology of YFV, along with an overview of the tools that can be used to manage the disease at the individual, local and global levels.
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Affiliation(s)
- Raphaëlle Klitting
- Unité des Virus Émergents (UVE: Aix-Marseille Univ⁻IRD 190⁻Inserm 1207⁻IHU Méditerranée Infection), 13385 Marseille CEDEX 05, France.
| | - Carlo Fischer
- Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Virology, 10117 Berlin, Germany.
- German Center for Infection Research (DZIF), 38124 Braunschweig, Germany.
| | - Jan F Drexler
- Charité-Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Virology, 10117 Berlin, Germany.
- German Center for Infection Research (DZIF), 38124 Braunschweig, Germany.
- Martsinovsky Institute of Medical Parasitology, Tropical and Vector Borne Diseases, Sechenov University, 119991 Moscow, Russia.
| | - Ernest A Gould
- Unité des Virus Émergents (UVE: Aix-Marseille Univ⁻IRD 190⁻Inserm 1207⁻IHU Méditerranée Infection), 13385 Marseille CEDEX 05, France.
| | - David Roiz
- UMR Maladies Infectieuses et Vecteurs: Écologie, Génétique Évolution et Contrôle (MIVEGEC: IRD, CNRS, Univ. Montpellier), 34394 Montpellier, France.
| | - Christophe Paupy
- UMR Maladies Infectieuses et Vecteurs: Écologie, Génétique Évolution et Contrôle (MIVEGEC: IRD, CNRS, Univ. Montpellier), 34394 Montpellier, France.
| | - Xavier de Lamballerie
- Unité des Virus Émergents (UVE: Aix-Marseille Univ⁻IRD 190⁻Inserm 1207⁻IHU Méditerranée Infection), 13385 Marseille CEDEX 05, France.
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26
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Early Events in Japanese Encephalitis Virus Infection: Viral Entry. Pathogens 2018; 7:pathogens7030068. [PMID: 30104482 PMCID: PMC6161159 DOI: 10.3390/pathogens7030068] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 07/31/2018] [Accepted: 08/06/2018] [Indexed: 12/15/2022] Open
Abstract
Japanese encephalitis virus (JEV), a mosquito-borne zoonotic flavivirus, is an enveloped positive-strand RNA virus that can cause a spectrum of clinical manifestations, ranging from mild febrile illness to severe neuroinvasive disease. Today, several killed and live vaccines are available in different parts of the globe for use in humans to prevent JEV-induced diseases, yet no antivirals are available to treat JEV-associated diseases. Despite the progress made in vaccine research and development, JEV is still a major public health problem in southern, eastern, and southeastern Asia, as well as northern Oceania, with the potential to become an emerging global pathogen. In viral replication, the entry of JEV into the cell is the first step in a cascade of complex interactions between the virus and target cells that is required for the initiation, dissemination, and maintenance of infection. Because this step determines cell/tissue tropism and pathogenesis, it is a promising target for antiviral therapy. JEV entry is mediated by the viral glycoprotein E, which binds virions to the cell surface (attachment), delivers them to endosomes (endocytosis), and catalyzes the fusion between the viral and endosomal membranes (membrane fusion), followed by the release of the viral genome into the cytoplasm (uncoating). In this multistep process, a collection of host factors are involved. In this review, we summarize the current knowledge on the viral and cellular components involved in JEV entry into host cells, with an emphasis on the initial virus-host cell interactions on the cell surface.
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27
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de Wispelaere M, Lian W, Potisopon S, Li PC, Jang J, Ficarro SB, Clark MJ, Zhu X, Kaplan JB, Pitts JD, Wales TE, Wang J, Engen JR, Marto JA, Gray NS, Yang PL. Inhibition of Flaviviruses by Targeting a Conserved Pocket on the Viral Envelope Protein. Cell Chem Biol 2018; 25:1006-1016.e8. [PMID: 29937406 DOI: 10.1016/j.chembiol.2018.05.011] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 04/23/2018] [Accepted: 05/16/2018] [Indexed: 11/28/2022]
Abstract
Viral envelope proteins are required for productive viral entry and initiation of infection. Although the humoral immune system provides ample evidence for targeting envelope proteins as an antiviral strategy, there are few pharmacological interventions that have this mode of action. In contrast to classical antiviral targets such as viral proteases and polymerases, viral envelope proteins as a class do not have a well-conserved active site that can be rationally targeted with small molecules. We previously identified compounds that inhibit dengue virus by binding to its envelope protein, E. Here, we show that these small molecules inhibit dengue virus fusion and map the binding site of these compounds to a specific pocket on E. We further demonstrate inhibition of Zika, West Nile, and Japanese encephalitis viruses by these compounds, providing pharmacological evidence for the pocket as a target for developing broad-spectrum antivirals against multiple, mosquito-borne flavivirus pathogens.
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Affiliation(s)
| | - Wenlong Lian
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Supanee Potisopon
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Pi-Chun Li
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School and Department of Cancer Biology, Dana-Farber Cancer Institute, 360 Longwood Avenue, Boston, MA 02215, USA
| | - Jaebong Jang
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School and Department of Cancer Biology, Dana-Farber Cancer Institute, 360 Longwood Avenue, Boston, MA 02215, USA
| | - Scott B Ficarro
- Department of Cancer Biology, Department of Oncologic Pathology, Blais Proteomics Center, Dana-Farber Cancer Institute, 360 Longwood Avenue, Boston, MA 02215, USA; Department of Pathology, Brigham and Women's Hospital, 45 Francis Street, Boston, MA 02115, USA
| | - Margaret J Clark
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Xuling Zhu
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Jenifer B Kaplan
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Jared D Pitts
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Thomas E Wales
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA
| | - Jinhua Wang
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School and Department of Cancer Biology, Dana-Farber Cancer Institute, 360 Longwood Avenue, Boston, MA 02215, USA
| | - John R Engen
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA
| | - Jarrod A Marto
- Department of Cancer Biology, Department of Oncologic Pathology, Blais Proteomics Center, Dana-Farber Cancer Institute, 360 Longwood Avenue, Boston, MA 02215, USA; Department of Pathology, Brigham and Women's Hospital, 45 Francis Street, Boston, MA 02115, USA
| | - Nathanael S Gray
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School and Department of Cancer Biology, Dana-Farber Cancer Institute, 360 Longwood Avenue, Boston, MA 02215, USA
| | - Priscilla L Yang
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA.
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28
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Rey FA, Stiasny K, Vaney MC, Dellarole M, Heinz FX. The bright and the dark side of human antibody responses to flaviviruses: lessons for vaccine design. EMBO Rep 2018; 19:206-224. [PMID: 29282215 PMCID: PMC5797954 DOI: 10.15252/embr.201745302] [Citation(s) in RCA: 160] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 11/21/2017] [Accepted: 11/23/2017] [Indexed: 01/07/2023] Open
Abstract
Zika and dengue viruses belong to the Flavivirus genus, a close group of antigenically related viruses that cause significant arthropod-transmitted diseases throughout the globe. Although infection by a given flavivirus is thought to confer lifelong protection, some of the patient's antibodies cross-react with other flaviviruses without cross-neutralizing. The original antigenic sin phenomenon may amplify such antibodies upon subsequent heterologous flavivirus infection, potentially aggravating disease by antibody-dependent enhancement (ADE). The most striking example is provided by the four different dengue viruses, where infection by one serotype appears to predispose to more severe disease upon infection by a second one. A similar effect was postulated for sequential infections with Zika and dengue viruses. In this review, we analyze the molecular determinants of the dual antibody response to flavivirus infection or vaccination in humans. We highlight the role of conserved partially cryptic epitopes giving rise to cross-reacting and poorly neutralizing, ADE-prone antibodies. We end by proposing a strategy for developing an epitope-focused vaccine approach to avoid eliciting undesirable antibodies while focusing the immune system on producing protective antibodies only.
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Affiliation(s)
- Félix A Rey
- Structural Virology Unit, Virology Department, Institut Pasteur, Paris, France
- CNRS UMR 3569, Paris, France
| | - Karin Stiasny
- Center for Virology, Medical University of Vienna, Vienna, Austria
| | - Marie-Christine Vaney
- Structural Virology Unit, Virology Department, Institut Pasteur, Paris, France
- CNRS UMR 3569, Paris, France
| | - Mariano Dellarole
- Structural Virology Unit, Virology Department, Institut Pasteur, Paris, France
- CNRS UMR 3569, Paris, France
| | - Franz X Heinz
- Center for Virology, Medical University of Vienna, Vienna, Austria
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29
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Structure of tick-borne encephalitis virus and its neutralization by a monoclonal antibody. Nat Commun 2018; 9:436. [PMID: 29382836 PMCID: PMC5789857 DOI: 10.1038/s41467-018-02882-0] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 01/03/2018] [Indexed: 02/04/2023] Open
Abstract
Tick-borne encephalitis virus (TBEV) causes 13,000 cases of human meningitis and encephalitis annually. However, the structure of the TBEV virion and its interactions with antibodies are unknown. Here, we present cryo-EM structures of the native TBEV virion and its complex with Fab fragments of neutralizing antibody 19/1786. Flavivirus genome delivery depends on membrane fusion that is triggered at low pH. The virion structure indicates that the repulsive interactions of histidine side chains, which become protonated at low pH, may contribute to the disruption of heterotetramers of the TBEV envelope and membrane proteins and induce detachment of the envelope protein ectodomains from the virus membrane. The Fab fragments bind to 120 out of the 180 envelope glycoproteins of the TBEV virion. Unlike most of the previously studied flavivirus-neutralizing antibodies, the Fab fragments do not lock the E-proteins in the native-like arrangement, but interfere with the process of virus-induced membrane fusion. The tick-borne encephalitis virus (TBEV) causes thousands of cases of meningitis and encephalitis annually. Here, the authors describe a cryo-EM structure of the TBEV virion bound by Fab fragments of the neutralizing antibody 19/1786, revealing a mechanism whereby this antibody prevents virus membrane fusion.
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30
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Hasan SS, Sevvana M, Kuhn RJ, Rossmann MG. Structural biology of Zika virus and other flaviviruses. Nat Struct Mol Biol 2018; 25:13-20. [PMID: 29323278 DOI: 10.1038/s41594-017-0010-8] [Citation(s) in RCA: 120] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 11/11/2017] [Indexed: 12/16/2022]
Abstract
Zika virus (ZIKV) is an enveloped, icosahedral flavivirus that has structural and functional similarities to other human flavivirus pathogens such as dengue (DENV), West Nile (WNV) and Japanese encephalitis (JEV) viruses. ZIKV infections have been linked to fetal microcephaly and the paralytic Guillain-Barré syndrome. This review provides a comparative structural analysis of the assembly, maturation and host-cell entry of ZIKV with other flaviviruses, especially DENV. We also discuss the mechanisms of neutralization by antibodies.
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Affiliation(s)
- S Saif Hasan
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Madhumati Sevvana
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Richard J Kuhn
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA
| | - Michael G Rossmann
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA.
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31
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Shi Y, Dai L, Song H, Gao GF. Structures of Zika Virus E & NS1: Relations with Virus Infection and Host Immune Responses. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1062:77-87. [PMID: 29845526 DOI: 10.1007/978-981-10-8727-1_6] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Zika virus (ZIKV), first discovered in the Zika forest in Uganda in 1947 was understudied until the recent explosive epidemic in several South American countries where it has become strongly associated with congenital birth defects leading to severe cranial malformations and neurological conditions. The increase in number of case of microcephaly in newborn children associated with ZIKV infection triggered the World Health Organization to declare the epidemic as a Public Health Emergency of International Concern in February of 2016. ZIKV is a member of the flavivirus genus and is transmitted by Aedes aegypti mosquitoes, however in the current epidemic clear evidence is emerging to suggest the virus can be sexually transmitted from human to human. The differences in epidemiology and manifestations of ZIKV infection during these outbreaks have prompted researchers to investigate mechanisms of dissemination, pathogenesis, and host immune response which contributes significantly to the control of the virus infection. The E and NS1 proteins of ZIKV are the major targets for neutralizing and protective antibodies. In this chapter, we mainly focus on recent research on the crystal structures of the ZIKV E and NS1 proteins, and their relations with virus infection and immune responses. These studies will be helpful to develop novel therapeutics and vaccines for protection and control of ZIKV infection.
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Affiliation(s)
- Yi Shi
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
| | - Lianpan Dai
- Research Network of Immunity and Health (RNIH), Beijing Institutes of Life Science, Chinese Academy of Sciences, Beijing, China
| | - Hao Song
- Research Network of Immunity and Health (RNIH), Beijing Institutes of Life Science, Chinese Academy of Sciences, Beijing, China
| | - George F Gao
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China. .,Research Network of Immunity and Health (RNIH), Beijing Institutes of Life Science, Chinese Academy of Sciences, Beijing, China.
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32
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Abstract
Tick-borne encephalitis virus (TBEV) belongs to the Flaviviridae family and Flavivirus genus. TBEV is maintained in transmission cycles between Ixodid ticks and wild mammalian hosts, particularly rodents. A wide range of animal species are also infected with TBEV by the bite of infected ticks, and TBEV infection causes fatal encephalitis in humans. TBEV is endemic widely in the Eurasian continent, and more than 10,000 cases of the disease are reported annually. In Japan, the 1st confirmed case of TBE was reported in the southern area of Hokkaido in 1993, and after 20 years, the 2nd to 4th cases were reported in Hokkaido in 2016 and 2017. Our sero-epizootiological survey indicated endemic foci of TBEV are widely distributed in Hokkaido and that those of TBEV or tick-borne flavivirus outside Hokkaido. In this review, I introduced recent topics of TBEV including newly developed diagnostic methods, epidemiology and pathogenesis of TBEV.
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33
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Haslwanter D, Blaas D, Heinz FX, Stiasny K. A novel mechanism of antibody-mediated enhancement of flavivirus infection. PLoS Pathog 2017; 13:e1006643. [PMID: 28915259 PMCID: PMC5617232 DOI: 10.1371/journal.ppat.1006643] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 09/27/2017] [Accepted: 09/11/2017] [Indexed: 12/12/2022] Open
Abstract
Antibody-dependent enhancement of viral infection is a well-described phenomenon that is based on the cellular uptake of infectious virus-antibody complexes following their interaction with Fcγ receptors expressed on myeloid cells. Here we describe a novel mechanism of antibody-mediated enhancement of infection by a flavivirus (tick-borne encephalitis virus) in transformed and primary human cells, which is independent of the presence of Fcγ receptors. Using chemical cross-linking and immunoassays, we demonstrate that the monoclonal antibody (mab) A5, recognizing an epitope at the interface of the dimeric envelope protein E, causes dimer dissociation and leads to the exposure of the fusion loop (FL). Under normal conditions of infection, this process is triggered only after virus uptake by the acidic pH in endosomes, resulting in the initiation of membrane fusion through the interaction of the FL with the endosomal membrane. Analysis of virus binding and cellular infection, together with inhibition by the FL-specific mab 4G2, indicated that the FL, exposed after mab A5- induced dimer-dissociation, mediated attachment of the virus to the plasma membrane also at neutral pH, thereby increasing viral infectivity. Since antibody-induced enhancement of binding was not only observed with cells but also with liposomes, it is likely that increased infection was due to FL-lipid interactions and not to interactions with cellular plasma membrane proteins. The novel mechanism of antibody-induced infection enhancement adds a new facet to the complexity of antibody interactions with flaviviruses and may have implications for yet unresolved effects of polyclonal antibody responses on biological properties of these viruses.
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Affiliation(s)
| | - Dieter Blaas
- Max F. Perutz Laboratories, Department for Medical Biochemistry, Medical University of Vienna, Vienna, Austria
| | - Franz X. Heinz
- Center for Virology, Medical University of Vienna, Vienna, Austria
| | - Karin Stiasny
- Center for Virology, Medical University of Vienna, Vienna, Austria
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Yap SSL, Nguyen-Khuong T, Rudd PM, Alonso S. Dengue Virus Glycosylation: What Do We Know? Front Microbiol 2017; 8:1415. [PMID: 28791003 PMCID: PMC5524768 DOI: 10.3389/fmicb.2017.01415] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Accepted: 07/12/2017] [Indexed: 12/04/2022] Open
Abstract
In many infectious diseases caused by either viruses or bacteria, pathogen glycoproteins play important roles during the infection cycle, ranging from entry to successful intracellular replication and host immune evasion. Dengue is no exception. Dengue virus glycoproteins, envelope protein (E) and non-structural protein 1 (NS1) are two popular sub-unit vaccine candidates. E protein on the virion surface is the major target of neutralizing antibodies. NS1 which is secreted during DENV infection has been shown to induce a variety of host responses through its binding to several host factors. However, despite their critical role in disease and protection, the glycosylated variants of these two proteins and their biological importance have remained understudied. In this review, we seek to provide a comprehensive summary of the current knowledge on protein glycosylation in DENV, and its role in virus biogenesis, host cell receptor interaction and disease pathogenesis.
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Affiliation(s)
- Sally S L Yap
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, and Immunology program, Life Sciences Institute, National University of SingaporeSingapore, Singapore
| | - Terry Nguyen-Khuong
- Analytics Group, Bioprocessing Technology Institute, A∗STARSingapore, Singapore
| | - Pauline M Rudd
- Analytics Group, Bioprocessing Technology Institute, A∗STARSingapore, Singapore
| | - Sylvie Alonso
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, and Immunology program, Life Sciences Institute, National University of SingaporeSingapore, Singapore
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Fernández-Sanlés A, Ríos-Marco P, Romero-López C, Berzal-Herranz A. Functional Information Stored in the Conserved Structural RNA Domains of Flavivirus Genomes. Front Microbiol 2017; 8:546. [PMID: 28421048 PMCID: PMC5376627 DOI: 10.3389/fmicb.2017.00546] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 03/15/2017] [Indexed: 02/05/2023] Open
Abstract
The genus Flavivirus comprises a large number of small, positive-sense single-stranded, RNA viruses able to replicate in the cytoplasm of certain arthropod and/or vertebrate host cells. The genus, which has some 70 member species, includes a number of emerging and re-emerging pathogens responsible for outbreaks of human disease around the world, such as the West Nile, dengue, Zika, yellow fever, Japanese encephalitis, St. Louis encephalitis, and tick-borne encephalitis viruses. Like other RNA viruses, flaviviruses have a compact RNA genome that efficiently stores all the information required for the completion of the infectious cycle. The efficiency of this storage system is attributable to supracoding elements, i.e., discrete, structural units with essential functions. This information storage system overlaps and complements the protein coding sequence and is highly conserved across the genus. It therefore offers interesting potential targets for novel therapeutic strategies. This review summarizes our knowledge of the features of flavivirus genome functional RNA domains. It also provides a brief overview of the main achievements reported in the design of antiviral nucleic acid-based drugs targeting functional genomic RNA elements.
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Affiliation(s)
- Alba Fernández-Sanlés
- Department of Molecular Biology, Instituto de Parasitología y Biomedicina "López-Neyra," Consejo Superior de Investigaciones Científicas (IPBLN-CSIC)Granada, Spain
| | - Pablo Ríos-Marco
- Department of Molecular Biology, Instituto de Parasitología y Biomedicina "López-Neyra," Consejo Superior de Investigaciones Científicas (IPBLN-CSIC)Granada, Spain
| | - Cristina Romero-López
- Department of Molecular Biology, Instituto de Parasitología y Biomedicina "López-Neyra," Consejo Superior de Investigaciones Científicas (IPBLN-CSIC)Granada, Spain
| | - Alfredo Berzal-Herranz
- Department of Molecular Biology, Instituto de Parasitología y Biomedicina "López-Neyra," Consejo Superior de Investigaciones Científicas (IPBLN-CSIC)Granada, Spain
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Unraveling the role of membrane microdomains during microbial infections. Cell Biol Toxicol 2017; 33:429-455. [PMID: 28275881 PMCID: PMC7088210 DOI: 10.1007/s10565-017-9386-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 02/06/2017] [Indexed: 01/06/2023]
Abstract
Infectious diseases pose major socioeconomic and health-related threats to millions of people across the globe. Strategies to combat infectious diseases derive from our understanding of the complex interactions between the host and specific bacterial, viral, and fungal pathogens. Lipid rafts are membrane microdomains that play important role in life cycle of microbes. Interaction of microbial pathogens with host membrane rafts influences not only their initial colonization but also their spread and the induction of inflammation. Therefore, intervention strategies aimed at modulating the assembly of membrane rafts and/or regulating raft-directed signaling pathways are attractive approaches for the. management of infectious diseases. The current review discusses the latest advances in terms of techniques used to study the role of membrane microdomains in various pathological conditions and provides updated information regarding the role of membrane rafts during bacterial, viral and fungal infections.
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Yun SI, Lee YM. Zika virus: An emerging flavivirus. J Microbiol 2017; 55:204-219. [PMID: 28243937 DOI: 10.1007/s12275-017-7063-6] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 02/15/2017] [Indexed: 01/18/2023]
Abstract
Zika virus (ZIKV) is a previously little-known flavivirus closely related to Japanese encephalitis, West Nile, dengue, and yellow fever viruses, all of which are primarily transmitted by blood-sucking mosquitoes. Since its discovery in Uganda in 1947, ZIKV has continued to expand its geographic range, from equatorial Africa and Asia to the Pacific Islands, then further afield to South and Central America and the Caribbean. Currently, ZIKV is actively circulating not only in much of Latin America and its neighbors but also in parts of the Pacific Islands and Southeast Asia. Although ZIKV infection generally causes only mild symptoms in some infected individuals, it is associated with a range of neuroimmunological disorders, including Guillain-Barré syndrome, meningoencephalitis, and myelitis. Recently, maternal ZIKV infection during pregnancy has been linked to neonatal malformations, resulting in various degrees of congenital abnormalities, microcephaly, and even abortion. Despite its emergence as an important public health problem, however, little is known about ZIKV biology, and neither vaccine nor drug is available to control ZIKV infection. This article provides a brief introduction to ZIKV with a major emphasis on its molecular virology, in order to help facilitate the development of diagnostics, therapeutics, and vaccines.
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Affiliation(s)
- Sang-Im Yun
- Department of Animal, Dairy, and Veterinary Sciences, Utah State University, Logan, UT, 84322-4815, USA
| | - Young-Min Lee
- Department of Animal, Dairy, and Veterinary Sciences, Utah State University, Logan, UT, 84322-4815, USA. .,Utah Science Technology and Research, College of Agriculture and Applied Sciences, Utah State University, Logan, UT, 84322-4815, USA.
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Characterization of cytopathic factors through genome-wide analysis of the Zika viral proteins in fission yeast. Proc Natl Acad Sci U S A 2017; 114:E376-E385. [PMID: 28049830 DOI: 10.1073/pnas.1619735114] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The Zika virus (ZIKV) causes microcephaly and the Guillain-Barré syndrome. Little is known about how ZIKV causes these conditions or which ZIKV viral protein(s) is responsible for the associated ZIKV-induced cytopathic effects, including cell hypertrophy, growth restriction, cell-cycle dysregulation, and cell death. We used fission yeast for the rapid, global functional analysis of the ZIKV genome. All 14 proteins or small peptides were produced under an inducible promoter, and we measured the intracellular localization and the specific effects on ZIKV-associated cytopathic activities of each protein. The subcellular localization of each ZIKV protein was in overall agreement with its predicted protein structure. Five structural and two nonstructural ZIKV proteins showed various levels of cytopathic effects. The expression of these ZIKV proteins restricted cell proliferation, induced hypertrophy, or triggered cellular oxidative stress leading to cell death. The expression of premembrane protein (prM) resulted in cell-cycle G1 accumulation, whereas membrane-anchored capsid (anaC), membrane protein (M), envelope protein (E), and nonstructural protein 4A (NS4A) caused cell-cycle G2/M accumulation. A mechanistic study revealed that NS4A-induced cellular hypertrophy and growth restriction were mediated specifically through the target of rapamycin (TOR) cellular stress pathway involving Tor1 and type 2A phosphatase activator Tip41. These findings should provide a reference for future research on the prevention and treatment of ZIKV diseases.
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Dai L, Wang Q, Qi J, Shi Y, Yan J, Gao GF. Molecular basis of antibody-mediated neutralization and protection against flavivirus. IUBMB Life 2016; 68:783-91. [DOI: 10.1002/iub.1556] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2016] [Accepted: 08/22/2016] [Indexed: 12/18/2022]
Affiliation(s)
- Lianpan Dai
- Research Network of Immunity and Health (RNIH), Beijing Institutes of Life Science, Chinese Academy of Sciences; Beijing China
| | - Qihui Wang
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering; Institute of Microbiology, Chinese Academy of Sciences; Beijing China
- Shenzhen Key Laboratory of Pathogen and Immunity; Shenzhen Third People's Hospital; Shenzhen China
| | - Jianxun Qi
- CAS Key Laboratory of Pathogenic Microbiology and Immunology; Institute of Microbiology, Chinese Academy of Sciences; Beijing China
| | - Yi Shi
- Research Network of Immunity and Health (RNIH), Beijing Institutes of Life Science, Chinese Academy of Sciences; Beijing China
- Shenzhen Key Laboratory of Pathogen and Immunity; Shenzhen Third People's Hospital; Shenzhen China
- CAS Key Laboratory of Pathogenic Microbiology and Immunology; Institute of Microbiology, Chinese Academy of Sciences; Beijing China
- Center for Influenza Research and Early-warning (CASCIRE), Chinese Academy of Sciences; Beijing China
- Savaid Medical School, University of Chinese Academy of Sciences; Beijing China
| | - Jinghua Yan
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering; Institute of Microbiology, Chinese Academy of Sciences; Beijing China
- Shenzhen Key Laboratory of Pathogen and Immunity; Shenzhen Third People's Hospital; Shenzhen China
- CAS Key Laboratory of Pathogenic Microbiology and Immunology; Institute of Microbiology, Chinese Academy of Sciences; Beijing China
- Savaid Medical School, University of Chinese Academy of Sciences; Beijing China
| | - George F. Gao
- Research Network of Immunity and Health (RNIH), Beijing Institutes of Life Science, Chinese Academy of Sciences; Beijing China
- Shenzhen Key Laboratory of Pathogen and Immunity; Shenzhen Third People's Hospital; Shenzhen China
- CAS Key Laboratory of Pathogenic Microbiology and Immunology; Institute of Microbiology, Chinese Academy of Sciences; Beijing China
- Center for Influenza Research and Early-warning (CASCIRE), Chinese Academy of Sciences; Beijing China
- Savaid Medical School, University of Chinese Academy of Sciences; Beijing China. National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention (China CDC); Beijing China
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Recovery of West Nile Virus Envelope Protein Domain III Chimeras with Altered Antigenicity and Mouse Virulence. J Virol 2016; 90:4757-4770. [PMID: 26912625 DOI: 10.1128/jvi.02861-15] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 02/20/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Flaviviruses are positive-sense, single-stranded RNA viruses responsible for millions of human infections annually. The envelope (E) protein of flaviviruses comprises three structural domains, of which domain III (EIII) represents a discrete subunit. The EIII gene sequence typically encodes epitopes recognized by virus-specific, potently neutralizing antibodies, and EIII is believed to play a major role in receptor binding. In order to assess potential interactions between EIII and the remainder of the E protein and to assess the effects of EIII sequence substitutions on the antigenicity, growth, and virulence of a representative flavivirus, chimeric viruses were generated using the West Nile virus (WNV) infectious clone, into which EIIIs from nine flaviviruses with various levels of genetic diversity from WNV were substituted. Of the constructs tested, chimeras containing EIIIs from Koutango virus (KOUV), Japanese encephalitis virus (JEV), St. Louis encephalitis virus (SLEV), and Bagaza virus (BAGV) were successfully recovered. Characterization of the chimeras in vitro and in vivo revealed differences in growth and virulence between the viruses, within vivo pathogenesis often not being correlated within vitro growth. Taken together, the data demonstrate that substitutions of EIII can allow the generation of viable chimeric viruses with significantly altered antigenicity and virulence. IMPORTANCE The envelope (E) glycoprotein is the major protein present on the surface of flavivirus virions and is responsible for mediating virus binding and entry into target cells. Several viable West Nile virus (WNV) variants with chimeric E proteins in which the putative receptor-binding domain (EIII) sequences of other mosquito-borne flaviviruses were substituted in place of the WNV EIII were recovered, although the substitution of several more divergent EIII sequences was not tolerated. The differences in virulence and tissue tropism observed with the chimeric viruses indicate a significant role for this sequence in determining the pathogenesis of the virus within the mammalian host. Our studies demonstrate that these chimeras are viable and suggest that such recombinant viruses may be useful for investigation of domain-specific antibody responses and the more extensive definition of the contributions of EIII to the tropism and pathogenesis of WNV or other flaviviruses.
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Mir A, Ismatullah H, Rauf S, Niazi UH. Identification of bioflavonoid as fusion inhibitor of dengue virus using molecular docking approach. INFORMATICS IN MEDICINE UNLOCKED 2016. [DOI: 10.1016/j.imu.2016.06.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
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Chaudhury S, Ripoll DR, Wallqvist A. Structure-based pKa prediction provides a thermodynamic basis for the role of histidines in pH-induced conformational transitions in dengue virus. Biochem Biophys Rep 2015; 4:375-385. [PMID: 29124227 PMCID: PMC5669449 DOI: 10.1016/j.bbrep.2015.10.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 10/28/2015] [Accepted: 10/29/2015] [Indexed: 11/21/2022] Open
Abstract
pH-induced conformational changes in dengue virus (DENV) are critical to its ability to infect host cells. The envelope protein heterodimers that make up the viral envelope shift from a dimer to a trimer conformation at low-pH during membrane fusion. Previous studies have suggested that the ionization of histidine residues at low-pH is central to this pH-induced conformational change. We sought out to use molecular modeling with structure-based pKa prediction to provide a quantitative basis for the role of histidines in pH-induced conformational changes and identify which histidine residues were primarily responsible for this transition. We combined existing crystallographic and cryo-electron microscopy data to construct templates of the dimer and trimer conformations for the mature and immature virus. We then generated homology models for the four DENV serotypes and carried out structure-based pKa prediction using Rosetta. Our results showed that the pKa values of a subset of conserved histidines in DENV successfully capture the thermodynamics necessary to drive pH-induced conformational changes during fusion. Here, we identified the structural determinants underlying these pKa values and compare our findings with previous experimental results. Structure-based pKa prediction for histidines in dengue virus was carried out. Conserved histidine residues drive pH-dependent conformation changes. The mature dimer form of the envelop protein is destabilized at low-pH.
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Affiliation(s)
- Sidhartha Chaudhury
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Materiel Command, Ft. Detrick, MD 21702, United States
| | - Daniel R Ripoll
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Materiel Command, Ft. Detrick, MD 21702, United States
| | - Anders Wallqvist
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Materiel Command, Ft. Detrick, MD 21702, United States
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Ishikawa T, Konishi E. Potential chemotherapeutic targets for Japanese encephalitis: current status of antiviral drug development and future challenges. Expert Opin Ther Targets 2015; 19:1379-95. [PMID: 26156208 DOI: 10.1517/14728222.2015.1065817] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
INTRODUCTION Japanese encephalitis (JE) remains a public health threat in Asia. Although several vaccines have been licensed, ∼ 67,900 cases of the disease are estimated to occur annually, probably because the vaccine coverage is low. Therefore, effective antiviral drugs are required to control JE. However, no licensed anti-JE drugs are available, despite extensive efforts to develop them. AREAS COVERED We provide a general overview of JE and JE virus, including its transmission cycle, distribution, structure, replication machinery, immune evasion mechanisms and vaccines. The current situation in antiviral drug development is then reviewed and future perspectives are discussed. EXPERT OPINION Although the development of effective anti-JE drugs is an urgent issue, only supportive care is currently available. Recent progress in our understanding of the viral replication machinery and immune evasion strategies has identified new targets for anti-JE drug development. To date, most candidate drugs have only been evaluated in single-drug formulations, and efficient drug delivery to the CNS has virtually not been considered. However, an effective anti-JE treatment is expected to be achieved with multiple-drug formulations and a targeted drug delivery system in the near future.
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Affiliation(s)
- Tomohiro Ishikawa
- a 1 Dokkyo Medical University, School of Medicine, Department of Microbiology , 880 Kitakobayashi, Mibu-machi, Shimotsuga-gun, Tochigi 321-0293, Japan
| | - Eiji Konishi
- b 2 Mahidol University, BIKEN Endowed Department of Dengue Vaccine Development, Faculty of Tropical Medicine , 420/6 Ratchawithi Road, Ratchathewi, Bangkok 10400, Thailand.,c 3 Osaka University, Research Institute for Microbial Diseases, BIKEN Endowed Department of Dengue Vaccine Development , 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan +66 2 354 5981 ;
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Morante K, Caaveiro JM, Viguera AR, Tsumoto K, González-Mañas JM. Functional characterization of Val60, a key residue involved in the membrane-oligomerization of fragaceatoxin C, an actinoporin fromActinia fragacea. FEBS Lett 2015; 589:1840-6. [DOI: 10.1016/j.febslet.2015.06.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Revised: 05/29/2015] [Accepted: 06/01/2015] [Indexed: 11/28/2022]
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Immunization with Immune Complexes Modulates the Fine Specificity of Antibody Responses to a Flavivirus Antigen. J Virol 2015; 89:7970-8. [PMID: 26018152 DOI: 10.1128/jvi.00938-15] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 05/11/2015] [Indexed: 12/30/2022] Open
Abstract
UNLABELLED The antibody response to proteins may be modulated by the presence of preexisting antigen-specific antibodies and the formation of immune complexes (ICs). Effects such as a general increase or decrease of the response as well as epitope-specific phenomena have been described. In this study, we investigated influences of IC immunization on the fine specificity of antibody responses in a structurally well-defined system, using the envelope (E) protein of tick-borne encephalitis (TBE) virus as an immunogen. TBE virus occurs in Europe and Asia and-together with the yellow fever, dengue, West Nile, and Japanese encephalitis viruses-represents one of the major human-pathogenic flaviviruses. Mice were immunized with a dimeric soluble form of E (sE) alone or in complex with monoclonal antibodies specific for each of the three domains of E, and the antibody response induced by these ICs was compared to that seen after immunization with sE alone. Immunoassays using recombinant domains and domain combinations of TBE virus sE as well as the distantly related West Nile virus sE allowed the dissection and quantification of antibody subsets present in postimmunization sera, thus generating fine-specificity patterns of the polyclonal responses. There were substantially different responses with two of the ICs, and the differences could be mechanistically related to (i) epitope shielding and (ii) antibody-mediated structural changes leading to dissociation of the sE dimer. The phenomena described may also be relevant for polyclonal responses upon secondary infections and/or booster immunizations and may affect antibody responses in an individual-specific way. IMPORTANCE Infections with flaviviruses such as yellow fever, dengue, Japanese encephalitis, West Nile, and tick-borne encephalitis (TBE) viruses pose substantial public health problems in different parts of the world. Antibodies to viral envelope protein E induced by natural infection or vaccination were shown to confer protection from disease. Such antibodies can target different epitopes in E protein, and the fine specificities of polyclonal responses can differ between individuals. We conducted a mouse immunization study with TBE E protein alone or complexed to monoclonal antibodies specific for each of the three protein domains. We demonstrated that phenomena such as epitope shielding and antibody-induced structural changes can profoundly influence the fine specificity of antibody responses to the same immunogen. The study thus provided important new information on the potential immunomodulatory role of preexisting antibodies in a flavivirus system that can be relevant for understanding individual-specific factors influencing antibody responses in sequential flavivirus infections and/or immunizations.
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Farias KJS, Machado PRL, Muniz JAPC, Imbeloni AA, da Fonseca BAL. Antiviral activity of chloroquine against dengue virus type 2 replication in Aotus monkeys. Viral Immunol 2015; 28:161-9. [PMID: 25664975 DOI: 10.1089/vim.2014.0090] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Dengue virus (DENV) of the Flaviviridae family is a single positive-stranded RNA virus that is transmitted by Aedes aegypti and Aedes albopictus mosquitoes. The objective of this study was to investigate the use of chloroquine (CLQ) as an antiviral drug against dengue virus in monkeys. To analyze the action of the drug in vivo, nonhuman primates groups (Aotus azarai infulatus) were inoculated with a subcutaneous injection of a virulent strain of DENV-2, treated and untreated CLQ. Blood hematological, viremia, and serum biochemical values were obtained from 16 DENV-2-inoculated, treated and untreated; four received only CLQ and one mock-infected Aotus monkeys. Monkey serum samples (day 0-10 post-inoculation) were assayed by reverse transcription polymerase chain reaction and Cytometric Bead Array for determination of viremia and inflammatory cytokines, respectively. Additionally, body temperature and activity levels were determined. In the present work, CLQ was effective on replication of DENV-2 in Aotus monkeys; a time viremia reduction was observed compared with the controls. The concentration of tumor necrosis factor alpha and interferon gamma in the serum of the animals had a statistically significant reduction in the groups treated with CLQ after infection compared with the controls. A significant decrease in systemic levels of the liver enzyme aspartate aminotransferase (AST) was also observed in the animals treated with CLQ after infection compared with the controls. These results suggest that CLQ interferes in DENV-2 replication in Aotus monkeys.
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Affiliation(s)
- Kleber Juvenal Silva Farias
- 1 Department of Internal Medicine, School of Medicine of Ribeirão Preto, University of São Paulo , São Paulo, Brazil
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Dejnirattisai W, Wongwiwat W, Supasa S, Zhang X, Dai X, Rouvinski A, Jumnainsong A, Edwards C, Quyen NTH, Duangchinda T, Grimes JM, Tsai WY, Lai CY, Wang WK, Malasit P, Farrar J, Simmons CP, Zhou ZH, Rey FA, Mongkolsapaya J, Screaton GR. A new class of highly potent, broadly neutralizing antibodies isolated from viremic patients infected with dengue virus. Nat Immunol 2015; 16:170-177. [PMID: 25501631 PMCID: PMC4445969 DOI: 10.1038/ni.3058] [Citation(s) in RCA: 354] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 11/18/2014] [Indexed: 02/06/2023]
Abstract
Dengue is a rapidly emerging, mosquito-borne viral infection, with an estimated 400 million infections occurring annually. To gain insight into dengue immunity, we characterized 145 human monoclonal antibodies (mAbs) and identified a previously unknown epitope, the envelope dimer epitope (EDE), that bridges two envelope protein subunits that make up the 90 repeating dimers on the mature virion. The mAbs to EDE were broadly reactive across the dengue serocomplex and fully neutralized virus produced in either insect cells or primary human cells, with 50% neutralization in the low picomolar range. Our results provide a path to a subunit vaccine against dengue virus and have implications for the design and monitoring of future vaccine trials in which the induction of antibody to the EDE should be prioritized.
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Affiliation(s)
- Wanwisa Dejnirattisai
- Division of Immunology and Inflammation, Department of Medicine, Faculty of Medicine, Hammersmith Campus, Imperial College, London, UK
| | - Wiyada Wongwiwat
- Division of Immunology and Inflammation, Department of Medicine, Faculty of Medicine, Hammersmith Campus, Imperial College, London, UK
| | - Sunpetchuda Supasa
- Division of Immunology and Inflammation, Department of Medicine, Faculty of Medicine, Hammersmith Campus, Imperial College, London, UK
- Dengue Hemorrhagic Fever Research Unit, Office for Research and Development, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
- Graduate Program in Immunology, Department of Immunology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Xiaokang Zhang
- Institut Pasteur, Département de Virologie, Unité de Virologie Structurale, Paris, France
- CNRS UMR 3569 Virologie, Paris, France
| | - Xinghong Dai
- Department of Microbiology, Immunology and Molecular Genetics and California NanoSystems Institute, University of California Los Angeles, Los Angeles, California, USA
| | - Alexander Rouvinski
- Institut Pasteur, Département de Virologie, Unité de Virologie Structurale, Paris, France
- CNRS UMR 3569 Virologie, Paris, France
| | - Amonrat Jumnainsong
- Division of Immunology and Inflammation, Department of Medicine, Faculty of Medicine, Hammersmith Campus, Imperial College, London, UK
- The Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | - Carolyn Edwards
- Division of Immunology and Inflammation, Department of Medicine, Faculty of Medicine, Hammersmith Campus, Imperial College, London, UK
| | - Nguyen Than Ha Quyen
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Program, Hospital for Tropical Diseases, Ho Chi Minh City, Viet Nam
| | - Thaneeya Duangchinda
- Medical Biotechnology Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathumthani, Thailand
| | - Jonathan M Grimes
- Division of Structural Biology and Oxford Protein Production Facility, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
- Science Division, Diamond Light Source, Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire, UK
| | - Wen-Yang Tsai
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Chih-Yun Lai
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Wei-Kung Wang
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Prida Malasit
- Dengue Hemorrhagic Fever Research Unit, Office for Research and Development, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
- Medical Biotechnology Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathumthani, Thailand
| | - Jeremy Farrar
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Program, Hospital for Tropical Diseases, Ho Chi Minh City, Viet Nam
| | - Cameron P Simmons
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Program, Hospital for Tropical Diseases, Ho Chi Minh City, Viet Nam
- Department of Microbiology and Immunology, University of Melbourne, Carlton, Victoria, Australia
| | - Z Hong Zhou
- Department of Microbiology, Immunology and Molecular Genetics and California NanoSystems Institute, University of California Los Angeles, Los Angeles, California, USA
| | - Felix A Rey
- Institut Pasteur, Département de Virologie, Unité de Virologie Structurale, Paris, France
- CNRS UMR 3569 Virologie, Paris, France
| | - Juthathip Mongkolsapaya
- Division of Immunology and Inflammation, Department of Medicine, Faculty of Medicine, Hammersmith Campus, Imperial College, London, UK
- Dengue Hemorrhagic Fever Research Unit, Office for Research and Development, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Gavin R Screaton
- Division of Immunology and Inflammation, Department of Medicine, Faculty of Medicine, Hammersmith Campus, Imperial College, London, UK
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Chao LH, Klein DE, Schmidt AG, Peña JM, Harrison SC. Sequential conformational rearrangements in flavivirus membrane fusion. eLife 2014; 3:e04389. [PMID: 25479384 PMCID: PMC4293572 DOI: 10.7554/elife.04389] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 12/04/2014] [Indexed: 01/08/2023] Open
Abstract
The West Nile Virus (WNV) envelope protein, E, promotes membrane fusion during viral cell entry by undergoing a low-pH triggered conformational reorganization. We have examined the mechanism of WNV fusion and sought evidence for potential intermediates during the conformational transition by following hemifusion of WNV virus-like particles (VLPs) in a single particle format. We have introduced specific mutations into E, to relate their influence on fusion kinetics to structural features of the protein. At the level of individual E subunits, trimer formation and membrane engagement of the threefold clustered fusion loops are rate-limiting. Hemifusion requires at least two adjacent trimers. Simulation of the kinetics indicates that availability of competent monomers within the contact zone between virus and target membrane makes trimerization a bottleneck in hemifusion. We discuss the implications of the model we have derived for mechanisms of membrane fusion in other contexts. DOI:http://dx.doi.org/10.7554/eLife.04389.001 Flaviviruses are a group of viruses that cause serious diseases in humans, including yellow fever, West Nile fever and dengue fever. Like all viruses, flaviviruses protect their genetic material with a protein shell and, like many other viruses, that shell also has a lipid membrane. Flaviruses use one of their surface membrane proteins, known as ‘envelope protein’ or simply ‘E’, to bind to the surface of host cells. Once the virus has attached to the host cell membrane, it becomes engulfed within a bubble-like structure called an endosome, which also has a surrounding membrane. The interior of an endosome is acidic. Under these conditions the E protein undergoes a series of changes that bring the two membranes into close contact, so that the membrane of the virus can fuse with the membrane of the endosome. This membrane fusion allows the genome of the virus to escape the endosome and hijack the cell to make new copies of the virus. The E proteins on a mature flavivirus particle are found in pairs, but previous work showed that these proteins must work together in groups of three (called ‘trimers’) for the viral and endosomal membranes to fuse. Chao et al. have now asked: what are the rate-limiting steps that lead to the formation of trimers? And how many trimers are necessary to cause the membranes to fuse? Chao et al. have investigated these questions using virus-like particles containing the E protein of West Nile Virus. They used techniques that can track individual particles, which their laboratory had previously used to investigate the influenza virus, to model changes in the E protein before, during and after membrane fusion. Chao et al. then made mutant versions of the envelope protein and used virus-like particles containing them to test the model. The data that Chao et al. obtained and computer simulations they carried out suggest that exposure to acidic conditions encourages the pairs of E proteins to separate and extend towards the endosome membrane. Individual E proteins then group together into trimers, and at least two trimers are needed to exert enough force to allow the membranes to fuse. The experimental design used by Chao et al. will now allow them to study the action of molecules that inhibit membrane fusion by West Nile Virus and other viruses. DOI:http://dx.doi.org/10.7554/eLife.04389.002
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Affiliation(s)
- Luke H Chao
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, United States
| | - Daryl E Klein
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, United States
| | - Aaron G Schmidt
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, United States
| | - Jennifer M Peña
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, United States
| | - Stephen C Harrison
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, United States
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Progress in the identification of dengue virus entry/fusion inhibitors. BIOMED RESEARCH INTERNATIONAL 2014; 2014:825039. [PMID: 25157370 PMCID: PMC4135166 DOI: 10.1155/2014/825039] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Accepted: 05/09/2014] [Indexed: 01/12/2023]
Abstract
Dengue fever, a reemerging disease, is putting nearly 2.5 billion people at risk worldwide. The number of infections and the geographic extension of dengue fever infection have increased in the past decade. The disease is caused by the dengue virus, a flavivirus that uses mosquitos Aedes sp. as vectors. The disease has several clinical manifestations, from the mild cold-like illness to the more serious hemorrhagic dengue fever and dengue shock syndrome. Currently, there is no approved drug for the treatment of dengue disease or an effective vaccine to fight the virus. Therefore, the search for antivirals against dengue virus is an active field of research. As new possible receptors and biological pathways of the virus biology are discovered, new strategies are being undertaken to identify possible antiviral molecules. Several groups of researchers have targeted the initial step in the infection as a potential approach to interfere with the virus. The viral entry process is mediated by viral proteins and cellular receptor molecules that end up in the endocytosis of the virion, the fusion of both membranes, and the release of viral RNA in the cytoplasm. This review provides an overview of the targets and progress that has been made in the quest for dengue virus entry inhibitors.
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Ishikawa T, Konishi E. Japanese encephalitis: epidemiology, prevention and current status of antiviral drug development. Expert Opin Orphan Drugs 2014. [DOI: 10.1517/21678707.2014.934222] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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