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Zeba A, Sekar K, Ganjiwale A. M Protein from Dengue virus oligomerizes to pentameric channel protein: in silico analysis study. Genomics Inform 2023; 21:e41. [PMID: 37813637 PMCID: PMC10584644 DOI: 10.5808/gi.23035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 06/12/2023] [Accepted: 07/11/2023] [Indexed: 10/11/2023] Open
Abstract
The Dengue virus M protein is a 75 amino acid polypeptide with two helical transmembranes (TM). The TM domain oligomerizes to form an ion channel, facilitating viral release from the host cells. The M protein has a critical role in the virus entry and life cycle, making it a potent drug target. The oligomerization of the monomeric protein was studied using ab initio modeling and molecular dynamics (MD) simulation in an implicit membrane environment. The representative structures obtained showed pentamer as the most stable oligomeric state, resembling an ion channel. Glutamic acid, threonine, serine, tryptophan, alanine, isoleucine form the pore-lining residues of the pentameric channel, conferring an overall negative charge to the channel with approximate length of 51.9 Å. Residue interaction analysis (RIN) for M protein shows that Ala94, Leu95, Ser112, Glu124, and Phe155 are the central hub residues representing the physicochemical interactions between domains. The virtual screening with 165 different ion channel inhibitors from the ion channel library shows monovalent ion channel blockers, namely lumacaftor, glipizide, gliquidone, glisoxepide, and azelnidipine to be the inhibitors with high docking scores. Understanding the three-dimensional structure of M protein will help design therapeutics and vaccines for Dengue infection.
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Affiliation(s)
- Ayesha Zeba
- Department of Life Sciences, Bangalore University, Bangalore, Karnataka 560056, India
| | - Kanagaraj Sekar
- Laboratory for Structural Biology and Bio-computing, Computational and Data Sciences, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Anjali Ganjiwale
- Department of Life Sciences, Bangalore University, Bangalore, Karnataka 560056, India
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A. Dowd K, Sirohi D, D. Speer S, VanBlargan LA, Chen RE, Mukherjee S, Whitener BM, Govero J, Aleshnick M, Larman B, Sukupolvi-Petty S, Sevvana M, Miller AS, Klose T, Zheng A, Koenig S, Kielian M, Kuhn RJ, Diamond MS, Pierson TC. prM-reactive antibodies reveal a role for partially mature virions in dengue virus pathogenesis. Proc Natl Acad Sci U S A 2023; 120:e2218899120. [PMID: 36638211 PMCID: PMC9933121 DOI: 10.1073/pnas.2218899120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 11/28/2022] [Indexed: 01/15/2023] Open
Abstract
Cleavage of the flavivirus premembrane (prM) structural protein during maturation can be inefficient. The contribution of partially mature flavivirus virions that retain uncleaved prM to pathogenesis during primary infection is unknown. To investigate this question, we characterized the functional properties of newly-generated dengue virus (DENV) prM-reactive monoclonal antibodies (mAbs) in vitro and using a mouse model of DENV disease. Anti-prM mAbs neutralized DENV infection in a virion maturation state-dependent manner. Alanine scanning mutagenesis and cryoelectron microscopy of anti-prM mAbs in complex with immature DENV defined two modes of attachment to a single antigenic site. In vivo, passive transfer of intact anti-prM mAbs resulted in an antibody-dependent enhancement of disease. However, protection against DENV-induced lethality was observed when the transferred mAbs were genetically modified to inhibit their ability to interact with Fcγ receptors. These data establish that in addition to mature forms of the virus, partially mature infectious prM+ virions can also contribute to pathogenesis during primary DENV infections.
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Affiliation(s)
- Kimberly A. Dowd
- Viral Pathogenesis Section, Laboratory of Viral Diseases, National Institutes of Health, Bethesda, MD20892
| | - Devika Sirohi
- Department of Biological Sciences, Purdue University, West Lafayette, IN47907
- Purdue Institute of Inflammation, Immunology, and Infectious Disease, Purdue University, West Lafayette, IN47907
| | - Scott D. Speer
- Viral Pathogenesis Section, Laboratory of Viral Diseases, National Institutes of Health, Bethesda, MD20892
| | - Laura A. VanBlargan
- Department of Medicine, Washington University School of Medicine, St. Louis, MO63110
| | - Rita E. Chen
- Department of Medicine, Washington University School of Medicine, St. Louis, MO63110
| | - Swati Mukherjee
- Viral Pathogenesis Section, Laboratory of Viral Diseases, National Institutes of Health, Bethesda, MD20892
| | - Bradley M. Whitener
- Department of Medicine, Washington University School of Medicine, St. Louis, MO63110
| | - Jennifer Govero
- Department of Medicine, Washington University School of Medicine, St. Louis, MO63110
| | - Maya Aleshnick
- Viral Pathogenesis Section, Laboratory of Viral Diseases, National Institutes of Health, Bethesda, MD20892
| | - Bridget Larman
- Viral Pathogenesis Section, Laboratory of Viral Diseases, National Institutes of Health, Bethesda, MD20892
| | - Soila Sukupolvi-Petty
- Department of Medicine, Washington University School of Medicine, St. Louis, MO63110
| | - Madhumati Sevvana
- Department of Biological Sciences, Purdue University, West Lafayette, IN47907
- Purdue Institute of Inflammation, Immunology, and Infectious Disease, Purdue University, West Lafayette, IN47907
| | - Andrew S. Miller
- Department of Biological Sciences, Purdue University, West Lafayette, IN47907
- Purdue Institute of Inflammation, Immunology, and Infectious Disease, Purdue University, West Lafayette, IN47907
| | - Thomas Klose
- Department of Biological Sciences, Purdue University, West Lafayette, IN47907
- Purdue Institute of Inflammation, Immunology, and Infectious Disease, Purdue University, West Lafayette, IN47907
| | - Aihua Zheng
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, NY10461
| | | | - Margaret Kielian
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, NY10461
| | - Richard J. Kuhn
- Department of Biological Sciences, Purdue University, West Lafayette, IN47907
- Purdue Institute of Inflammation, Immunology, and Infectious Disease, Purdue University, West Lafayette, IN47907
| | - Michael S. Diamond
- Department of Medicine, Washington University School of Medicine, St. Louis, MO63110
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO63110
- Department of Pathology & Immunology, Washington University School of Medicine, St. Louis, MO63110
| | - Theodore C. Pierson
- Viral Pathogenesis Section, Laboratory of Viral Diseases, National Institutes of Health, Bethesda, MD20892
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Khare B, Kuhn RJ. The Japanese Encephalitis Antigenic Complex Viruses: From Structure to Immunity. Viruses 2022; 14:2213. [PMID: 36298768 PMCID: PMC9607441 DOI: 10.3390/v14102213] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 09/30/2022] [Accepted: 10/04/2022] [Indexed: 11/09/2022] Open
Abstract
In the last three decades, several flaviviruses of concern that belong to different antigenic groups have expanded geographically. This has resulted in the presence of often more than one virus from a single antigenic group in some areas, while in Europe, Africa and Australia, additionally, multiple viruses belonging to the Japanese encephalitis (JE) serogroup co-circulate. Morphological heterogeneity of flaviviruses dictates antibody recognition and affects virus neutralization, which influences infection control. The latter is further impacted by sequential infections involving diverse flaviviruses co-circulating within a region and their cross-reactivity. The ensuing complex molecular virus-host interplay leads to either cross-protection or disease enhancement; however, the molecular determinants and mechanisms driving these outcomes are unclear. In this review, we provide an overview of the epidemiology of four JE serocomplex viruses, parameters affecting flaviviral heterogeneity and antibody recognition, host immune responses and the current knowledge of the cross-reactivity involving JE serocomplex flaviviruses that leads to differential clinical outcomes, which may inform future preventative and therapeutic interventions.
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Affiliation(s)
- Baldeep Khare
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Richard J. Kuhn
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
- Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN 47907, USA
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Kumar S, Verma A, Yadav P, Dubey SK, Azhar EI, Maitra SS, Dwivedi VD. Molecular pathogenesis of Japanese encephalitis and possible therapeutic strategies. Arch Virol 2022; 167:1739-1762. [PMID: 35654913 PMCID: PMC9162114 DOI: 10.1007/s00705-022-05481-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Accepted: 03/10/2022] [Indexed: 12/26/2022]
Abstract
Japanese encephalitis virus (JEV), a single-stranded, enveloped RNA virus, is a health concern across Asian countries, associated with severe neurological disorders, especially in children. Primarily, pigs, bats, and birds are the natural hosts for JEV, but humans are infected incidentally. JEV requires a few host proteins for its entry and replication inside the mammalian host cell. The endoplasmic reticulum (ER) plays a significant role in JEV genome replication and assembly. During this process, the ER undergoes stress due to its remodelling and accumulation of viral particles and unfolded proteins, leading to an unfolded protein response (UPR). Here, we review the overall strategy used by JEV to infect the host cell and various cytopathic effects caused by JEV infection. We also highlight the role of JEV structural proteins (SPs) and non-structural proteins (NSPs) at various stages of the JEV life cycle that are involved in up- and downregulation of different host proteins and are potentially relevant for developing efficient therapeutic drugs.
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Affiliation(s)
- Sanjay Kumar
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110067 India
- Center for Bioinformatics, Computational and Systems Biology, Pathfinder Research and Training Foundation, Greater Noida, India
| | - Akanksha Verma
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110067 India
| | - Pardeep Yadav
- Department of Biotechnology, School of Engineering and Technology, Sharda University, Greater Noida, Uttar Pradesh 201310 India
- Center for Bioinformatics, Computational and Systems Biology, Pathfinder Research and Training Foundation, Greater Noida, India
| | | | - Esam Ibraheem Azhar
- Special Infectious Agents Unit-BSL3, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
- Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, 21589 Saudi Arabia
| | - S. S. Maitra
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110067 India
| | - Vivek Dhar Dwivedi
- Center for Bioinformatics, Computational and Systems Biology, Pathfinder Research and Training Foundation, Greater Noida, India
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De S, Aamna B, Sahu R, Parida S, Behera SK, Dan AK. Seeking heterocyclic scaffolds as antivirals against dengue virus. Eur J Med Chem 2022; 240:114576. [PMID: 35816877 PMCID: PMC9250831 DOI: 10.1016/j.ejmech.2022.114576] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 06/24/2022] [Accepted: 06/25/2022] [Indexed: 12/20/2022]
Abstract
Dengue is one of the most typical viral infection categorized in the Neglected Tropical Diseases (NTDs). It is transmitted via the female Aedes aegypti mosquito to humans and majorly puts risk to the lives of more than half of the world. Recent advancements in medicinal chemistry have led to the design and development of numerous potential heterocyclic scaffolds as antiviral drug candidates for the inhibition of the dengue virus (DENV). Thus, in this review, we have discussed the significance of inhibitory and antiviral activities of nitrogen, oxygen, and mixed (nitrogen-sulfur and nitrogen-oxygen) heterocyclic scaffolds that are published in the last seven years (2016–2022). Furthermore, we have also discussed the probable mechanisms of action and the diverse structure-activity relationships (SARs) of the heterocyclic scaffolds. In addition, this review has elaborately outlined the mechanism of viral infection and the life cycle of DENV in the host cells. The wide set of heterocycles and their SARs will aid in the development of pharmaceuticals that will allow the researchers to synthesize the promising anti-dengue drug candidate in the future.
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Human Polymorphonuclear Cells Support Zika Virus to Cross Endothelial Monolayer and Access Bloodstream. Pathogens 2022; 11:pathogens11030321. [PMID: 35335645 PMCID: PMC8955922 DOI: 10.3390/pathogens11030321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 02/27/2022] [Accepted: 03/03/2022] [Indexed: 11/16/2022] Open
Abstract
The rapid spread of new outbreaks of human infection caused by Zika virus (ZIKV) has raised many global concerns since 2016. Despite the increasing knowledge of this virus, data on the pathogenesis of ZIKV are still missing. In particular, it is still unknown how the virus crosses the endothelial monolayer and gets access to the bloodstream. In the present work, we used human umbilical vein endothelial cells (HUVECs) as a model to study ZIKV infection in vitro. We demonstrated that HUVECs are an optimal reservoir for viral replication, as they were able to sustain ZIKV infection up to two weeks, without showing a cytopathic effect. In order to evaluate the integrity of endothelial monolayer, immunofluorescence was performed on mock-infected or ZIKV-infected cells ± peripheral blood mononuclear cells (PBMCs) or polymorphonuclear cells (PMN), 48 h p.i., by using an anti-VE-Cadherin antibody, a major adherence protein that maintains the integrity of intercellular junctions. In addition to infection, we noted that the presence of some components of the immune system, such as PMNs, played an important role in altering the endothelial monolayer in cell junctions, suggesting that presence at the site of infection probably promotes the spread of ZIKV in vivo in the bloodstream.
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Hsieh SC, Tsai WY, Wang WK. Obtention of Dengue Virus Membrane Proteins and Role for Virus Assembly. Methods Mol Biol 2022; 2409:63-76. [PMID: 34709636 DOI: 10.1007/978-1-0716-1879-0_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2023]
Abstract
The four serotypes of dengue virus (DENV), belonging to the genus Flavivirus in the family Flaviviridae, are the leading cause of arboviral diseases in humans. The clinical presentations range from dengue fever to dengue hemorrhagic fever and dengue shock syndrome. Despite decades of efforts on developing intervention strategies against DENV, there is no licensed antiviral, and safe and effective vaccines remain challenging. Similar to other flaviviruses, the assembly of DENV particles occurs in the membranes derived from endoplasmic reticulum; immature virions bud into the lumen followed by maturation in the trans-Golgi and transport through the secretary pathway. A unique feature of flavivirus replication is the production of small and slowly sedimenting subviral particles, known as virus-like particles (VLPs). Co-expression of premembrane (prM) and envelope (E) proteins can generate recombinant VLPs, which are biophysically and antigenically similar to infectious virions and have been employed to study the function of prM and E proteins, assembly, serodiagnostic antigens, and vaccine candidates. Previously, we have developed several assays including sucrose cushion ultracentrifugation, sucrose gradient ultracentrifugation, membrane flotation, subcellular fractionation, and glycosidase digestion assay to exploit the interaction between DENV prM and E proteins, membrane association, subcellular localization, glycosylation pattern, and assembly of VLPs and replicon particles. The information derived from these assays have implications to further our understanding of DENV assembly, replication cycle, intervention strategies, and pathogenesis.
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Affiliation(s)
- Szu-Chia Hsieh
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Wen-Yang Tsai
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Wei-Kung Wang
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI, USA.
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Current Trends and Limitations in Dengue Antiviral Research. Trop Med Infect Dis 2021; 6:tropicalmed6040180. [PMID: 34698303 PMCID: PMC8544673 DOI: 10.3390/tropicalmed6040180] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 09/22/2021] [Accepted: 09/24/2021] [Indexed: 12/13/2022] Open
Abstract
Dengue is the most prevalent arthropod-borne viral disease worldwide and affects approximately 2.5 billion people living in over 100 countries. Increasing geographic expansion of Aedes aegypti mosquitoes (which transmit the virus) has made dengue a global health concern. There are currently no approved antivirals available to treat dengue, and the only approved vaccine used in some countries is limited to seropositive patients. Treatment of dengue, therefore, remains largely supportive to date; hence, research efforts are being intensified for the development of antivirals. The nonstructural proteins, 3 and 5 (NS3 and NS5), have been the major targets for dengue antiviral development due to their indispensable enzymatic and biological functions in the viral replication process. NS5 is the largest and most conserved nonstructural protein encoded by flaviviruses. Its multifunctionality makes it an attractive target for antiviral development, but research efforts have, this far, not resulted in the successful development of an antiviral targeting NS5. Increase in structural insights into the dengue NS5 protein will accelerate drug discovery efforts focused on NS5 as an antiviral target. In this review, we will give an overview of the current state of therapeutic development, with a focus on NS5 as a therapeutic target against dengue.
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Nakayama E, Kato F, Tajima S, Ogawa S, Yan K, Takahashi K, Sato Y, Suzuki T, Kawai Y, Inagaki T, Taniguchi S, Le TT, Tang B, Prow NA, Uda A, Maeki T, Lim CK, Khromykh AA, Suhrbier A, Saijo M. Neuroinvasiveness of the MR766 strain of Zika virus in IFNAR-/- mice maps to prM residues conserved amongst African genotype viruses. PLoS Pathog 2021; 17:e1009788. [PMID: 34310650 PMCID: PMC8341709 DOI: 10.1371/journal.ppat.1009788] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 08/05/2021] [Accepted: 07/07/2021] [Indexed: 12/23/2022] Open
Abstract
Zika virus (ZIKV) strains are classified into the African and Asian genotypes. The higher virulence of the African MR766 strain, which has been used extensively in ZIKV research, in adult IFNα/β receptor knockout (IFNAR-/-) mice is widely viewed as an artifact associated with mouse adaptation due to at least 146 passages in wild-type suckling mouse brains. To gain insights into the molecular determinants of MR766's virulence, a series of genes from MR766 were swapped with those from the Asian genotype PRVABC59 isolate, which is less virulent in IFNAR-/- mice. MR766 causes 100% lethal infection in IFNAR-/- mice, but when the prM gene of MR766 was replaced with that of PRVABC59, the chimera MR/PR(prM) showed 0% lethal infection. The reduced virulence was associated with reduced neuroinvasiveness, with MR766 brain titers ≈3 logs higher than those of MR/PR(prM) after subcutaneous infection, but was not significantly different in brain titers of MR766 and MR/PR(prM) after intracranial inoculation. MR/PR(prM) also showed reduced transcytosis when compared with MR766 in vitro. The high neuroinvasiveness of MR766 in IFNAR-/- mice could be linked to the 10 amino acids that differ between the prM proteins of MR766 and PRVABC59, with 5 of these changes affecting positive charge and hydrophobicity on the exposed surface of the prM protein. These 10 amino acids are highly conserved amongst African ZIKV isolates, irrespective of suckling mouse passage, arguing that the high virulence of MR766 in adult IFNAR-/- mice is not the result of mouse adaptation.
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Affiliation(s)
- Eri Nakayama
- Department of Virology I, National Institute of Infectious Diseases, Tokyo, Japan
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Fumihiro Kato
- Department of Virology I, National Institute of Infectious Diseases, Tokyo, Japan
| | - Shigeru Tajima
- Department of Virology I, National Institute of Infectious Diseases, Tokyo, Japan
| | - Shinya Ogawa
- Department of Applied Biological Chemistry, School of Agriculture and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Kexin Yan
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Kenta Takahashi
- Department of Pathology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Yuko Sato
- Department of Pathology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Tadaki Suzuki
- Department of Pathology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Yasuhiro Kawai
- Management Department of Biosafety and Laboratory Animal, Division of Biosafety Control and Research, National Institute of Infectious Diseases, Tokyo, Japan
| | - Takuya Inagaki
- Department of Virology I, National Institute of Infectious Diseases, Tokyo, Japan
| | - Satoshi Taniguchi
- Department of Virology I, National Institute of Infectious Diseases, Tokyo, Japan
| | - Thuy T. Le
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Bing Tang
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Natalie A. Prow
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
- Australian Infectious Disease Research Centre, GVN Center of Excellence, The University of Queensland and QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Akihiko Uda
- Department of Veterinary Science, National Institute of Infectious Diseases, Tokyo, Japan
| | - Takahiro Maeki
- Department of Virology I, National Institute of Infectious Diseases, Tokyo, Japan
| | - Chang-Kweng Lim
- Department of Virology I, National Institute of Infectious Diseases, Tokyo, Japan
| | - Alexander A. Khromykh
- Australian Infectious Disease Research Centre, GVN Center of Excellence, The University of Queensland and QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Andreas Suhrbier
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
- Australian Infectious Disease Research Centre, GVN Center of Excellence, The University of Queensland and QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Masayuki Saijo
- Department of Virology I, National Institute of Infectious Diseases, Tokyo, Japan
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Tangudu CS, Charles J, Nunez-Avellaneda D, Hargett AM, Brault AC, Blitvich BJ. Chimeric Zika viruses containing structural protein genes of insect-specific flaviviruses cannot replicate in vertebrate cells due to entry and post-translational restrictions. Virology 2021; 559:30-39. [PMID: 33812340 DOI: 10.1016/j.virol.2021.03.014] [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: 02/08/2021] [Revised: 03/04/2021] [Accepted: 03/21/2021] [Indexed: 02/06/2023]
Abstract
Long Pine Key virus (LPKV) and Lammi virus are insect-specific flaviviruses that phylogenetically affiliate with dual-host flaviviruses. The goal of this study was to provide insight into the genetic determinants that condition this host range restriction. Chimeras were initially created by replacing select regions of the Zika virus genome, including the premembrane and envelope protein (prM-E) genes, with the corresponding regions of the LPKV genome. Of the four chimeras produced, one (the prM-E swap) yielded virus that replicated in mosquito cells. Another chimeric virus with a mosquito replication-competent phenotype was created by inserting the prM-E genes of Lammi virus into a Zika virus genetic background. Vertebrate cells did not support the replication of either chimeric virus although trace to modest amounts of viral antigen were produced, consistent with suboptimal viral entry. These data suggest that dual-host affiliated insect-specific flaviviruses cannot replicate in vertebrate cells due to entry and post-translational restrictions.
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Affiliation(s)
- Chandra S Tangudu
- Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
| | - Jermilia Charles
- Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
| | - Daniel Nunez-Avellaneda
- Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
| | - Alissa M Hargett
- Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA
| | - Aaron C Brault
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, USA
| | - Bradley J Blitvich
- Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, USA.
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Maddipati VC, Mittal L, Mantipally M, Asthana S, Bhattacharyya S, Gundla R. A Review on the Progress and Prospects of Dengue Drug Discovery Targeting NS5 RNA- Dependent RNA Polymerase. Curr Pharm Des 2021; 26:4386-4409. [PMID: 32445444 DOI: 10.2174/1381612826666200523174753] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Accepted: 04/15/2020] [Indexed: 02/08/2023]
Abstract
Dengue virus (DENV) infection threatens the health and wellbeing of almost 100 million people in the world. Vectored by mosquitoes, DENV may cause a severe disease in human hosts called Dengue hemorrhagic fever (DHF)/Dengue shock syndrome (DSS), which is not preventable by any known drug. In the absence of a universally-accepted vaccine, a drug capable of inhibiting DENV multiplication is an urgent and unmet clinical need. Here we summarize inhibitory strategies by targeting either host biochemical pathways or virus-encoded proteins. A variety of approaches have been generated to design Directly-acting anti-virals or DAAs targeting different DENV proteins, with diverse success. Among them, DAAs targeting genome replicating viral enzymes have proven effective against many viruses including, Human Immuno-deficiency Virus and Hepatitis C Virus. DAAs may be derived either from existing compound libraries of novel molecules and plant secondary metabolites or devised through Computer-aided Drug design (CADD) methods. Here, we focus on compounds with reported DAA-activity against the DENV RNA-dependent RNA polymerase (RdRp), which replicate the viral RNA genome. The structure-activity relationship (SAR) and toxicity of the natural compounds, including secondary plant metabolites, have been discussed in detail. We have also tabulated novel compounds with known anti-RdRp activity. We concluded with a list of DAAs for which a co-crystal structure with RdRp is reported. Promising hit compounds are often discarded due to poor selectivity or unsuitable pharmacokinetics. We hope this review will provide a useful reference for further studies on the development of an anti-DENV drug.
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Affiliation(s)
- Venkatanarayana C Maddipati
- Department of Chemistry, School of Science, GITAM (Deemed to be University), Hyderabad 502329, Telangana, India
| | - Lovika Mittal
- Translational Health Science and Technology Institute (THSTI), NCR Biotech Science Cluster, 3rdMilestone, Faridabad-Gurugram Expressway, Faridabad - 121001, Haryana, India
| | - Manohar Mantipally
- Department of Chemistry, School of Science, GITAM (Deemed to be University), Hyderabad 502329, Telangana, India
| | - Shailendra Asthana
- Translational Health Science and Technology Institute (THSTI), NCR Biotech Science Cluster, 3rdMilestone, Faridabad-Gurugram Expressway, Faridabad - 121001, Haryana, India
| | - Sankar Bhattacharyya
- Translational Health Science and Technology Institute (THSTI), NCR Biotech Science Cluster, 3rdMilestone, Faridabad-Gurugram Expressway, Faridabad - 121001, Haryana, India
| | - Rambabu Gundla
- Department of Chemistry, School of Science, GITAM (Deemed to be University), Hyderabad 502329, Telangana, India
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12
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Fiacre L, Pagès N, Albina E, Richardson J, Lecollinet S, Gonzalez G. Molecular Determinants of West Nile Virus Virulence and Pathogenesis in Vertebrate and Invertebrate Hosts. Int J Mol Sci 2020; 21:ijms21239117. [PMID: 33266206 PMCID: PMC7731113 DOI: 10.3390/ijms21239117] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 11/23/2020] [Accepted: 11/26/2020] [Indexed: 12/12/2022] Open
Abstract
West Nile virus (WNV), like the dengue virus (DENV) and yellow fever virus (YFV), are major arboviruses belonging to the Flavivirus genus. WNV is emerging or endemic in many countries around the world, affecting humans and other vertebrates. Since 1999, it has been considered to be a major public and veterinary health problem, causing diverse pathologies, ranging from a mild febrile state to severe neurological damage and death. WNV is transmitted in a bird–mosquito–bird cycle, and can occasionally infect humans and horses, both highly susceptible to the virus but considered dead-end hosts. Many studies have investigated the molecular determinants of WNV virulence, mainly with the ultimate objective of guiding vaccine development. Several vaccines are used in horses in different parts of the world, but there are no licensed WNV vaccines for humans, suggesting the need for greater understanding of the molecular determinants of virulence and antigenicity in different hosts. Owing to technical and economic considerations, WNV virulence factors have essentially been studied in rodent models, and the results cannot always be transported to mosquito vectors or to avian hosts. In this review, the known molecular determinants of WNV virulence, according to invertebrate (mosquitoes) or vertebrate hosts (mammalian and avian), are presented and discussed. This overview will highlight the differences and similarities found between WNV hosts and models, to provide a foundation for the prediction and anticipation of WNV re-emergence and its risk of global spread.
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Affiliation(s)
- Lise Fiacre
- UMR 1161 Virology, ANSES, INRAE, ENVA, ANSES Animal Health Laboratory, EURL for Equine Diseases, 94704 Maisons-Alfort, France; (L.F.); (J.R.); (G.G.)
- CIRAD, UMR ASTRE, F-97170 Petit Bourg, Guadeloupe, France; (N.P.); (E.A.)
- ASTRE, University Montpellier, CIRAD, INRAE, F-34398 Montpellier, France
| | - Nonito Pagès
- CIRAD, UMR ASTRE, F-97170 Petit Bourg, Guadeloupe, France; (N.P.); (E.A.)
- ASTRE, University Montpellier, CIRAD, INRAE, F-34398 Montpellier, France
| | - Emmanuel Albina
- CIRAD, UMR ASTRE, F-97170 Petit Bourg, Guadeloupe, France; (N.P.); (E.A.)
- ASTRE, University Montpellier, CIRAD, INRAE, F-34398 Montpellier, France
| | - Jennifer Richardson
- UMR 1161 Virology, ANSES, INRAE, ENVA, ANSES Animal Health Laboratory, EURL for Equine Diseases, 94704 Maisons-Alfort, France; (L.F.); (J.R.); (G.G.)
| | - Sylvie Lecollinet
- UMR 1161 Virology, ANSES, INRAE, ENVA, ANSES Animal Health Laboratory, EURL for Equine Diseases, 94704 Maisons-Alfort, France; (L.F.); (J.R.); (G.G.)
- Correspondence: ; Tel.: +33-1-43967376
| | - Gaëlle Gonzalez
- UMR 1161 Virology, ANSES, INRAE, ENVA, ANSES Animal Health Laboratory, EURL for Equine Diseases, 94704 Maisons-Alfort, France; (L.F.); (J.R.); (G.G.)
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13
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Ins and Outs of Reovirus: Vesicular Trafficking in Viral Entry and Egress. Trends Microbiol 2020; 29:363-375. [PMID: 33008713 PMCID: PMC7523517 DOI: 10.1016/j.tim.2020.09.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 09/02/2020] [Accepted: 09/04/2020] [Indexed: 12/11/2022]
Abstract
Cell entry and egress are essential steps in the viral life cycle that govern pathogenesis and spread. Mammalian orthoreoviruses (reoviruses) are nonenveloped viruses implicated in human disease that serve as tractable models for studies of pathogen-host interactions. In this review we discuss the function of intracellular vesicular transport systems in reovirus entry, trafficking, and egress and comment on shared themes for diverse viruses. Designing strategic therapeutic interventions that impede these steps in viral replication requires a detailed understanding of mechanisms by which viruses coopt vesicular trafficking. We illuminate such targets, which may foster development of antiviral agents.
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14
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Cryo-EM Structures of Eastern Equine Encephalitis Virus Reveal Mechanisms of Virus Disassembly and Antibody Neutralization. Cell Rep 2019; 25:3136-3147.e5. [PMID: 30540945 PMCID: PMC6302666 DOI: 10.1016/j.celrep.2018.11.067] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 10/01/2018] [Accepted: 11/15/2018] [Indexed: 01/08/2023] Open
Abstract
Alphaviruses are enveloped pathogens that cause arthritis and encephalitis. Here, we report a 4.4-Å cryoelectron microscopy (cryo-EM) structure of eastern equine encephalitis virus (EEEV), an alphavirus that causes fatal encephalitis in humans. Our analysis provides insights into viral entry into host cells. The envelope protein E2 showed a binding site for the cellular attachment factor heparan sulfate. The presence of a cryptic E2 glycan suggests how EEEV escapes surveillance by lectin-expressing myeloid lineage cells, which are sentinels of the immune system. A mechanism for nucleocapsid core release and disassembly upon viral entry was inferred based on pH changes and capsid dissociation from envelope proteins. The EEEV capsid structure showed a viral RNA genome binding site adjacent to a ribosome binding site for viral genome translation following genome release. Using five Fab-EEEV complexes derived from neutralizing antibodies, our investigation provides insights into EEEV host cell interactions and protective epitopes relevant to vaccine design. EEEV cryo-EM structure shows the basis of receptor binding and pH-triggered disassembly Cryptic envelope protein glycosylation interferes with immune detection EEEV RNA genome binding site on capsid protein has an extended conformation Antibody inhibition of EEEV entry involves cross-linking of viral envelope proteins
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15
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Davis EH, Barrett ADT. Structure-Function of the Yellow Fever Virus Envelope Protein: Analysis of Antibody Epitopes. Viral Immunol 2019; 33:12-21. [PMID: 31682201 DOI: 10.1089/vim.2019.0107] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Yellow fever virus (YFV) is the prototype member of the genus Flavivirus, which contains more than 60 positive-sense, single-stranded RNA viruses, many of which are considered public health threats. YF disease is controlled by a live attenuated vaccine, 17D, which was generated empirically through serial passage of the wild-type (WT) strain Asibi in chicken tissue. The vaccine, which has been used for over 80 years, is considered to be one of the safest and most effective live attenuated vaccines. It has been shown that the humoral immune response is essential to a positive disease outcome during infection. As such, the neutralizing antibody response and its correlation to long-term protection are a critical measure of 17D efficacy. The primary target of these antibodies is the envelope (E) protein, which is the major component of the virion. Monoclonal antibodies can distinguish WT strain Asibi and vaccine strain 17D by many different measures, including physical binding, hemagglutination inhibition, neutralization, and passive protection. This makes the WT-vaccine pair ideal candidates to study the structure-function relationship of the E protein in the attenuation and immunogenicity of flaviviruses. In this study, we provide an overview of structure-function of YFV E protein and its involvement in protective immunity.
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Affiliation(s)
- Emily H Davis
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas.,Sealy Institute for Vaccine Sciences, University of Texas Medical Branch, Galveston, Texas
| | - Alan D T Barrett
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas.,Sealy Institute for Vaccine Sciences, University of Texas Medical Branch, Galveston, Texas
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16
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Cáceres Munar BA, Castellanos Parra JE, Rodríguez Panduro MH. Amplificación de la infección dependiente de anticuerpos en la inmunopatogénesis del dengue grave, implicaciones para el desarrollo y uso de las vacunas. ACTA BIOLÓGICA COLOMBIANA 2019. [DOI: 10.15446/abc.v24n3.79410] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Actualmente, la infección por el virus de dengue (DENV) es uno de los problemas más importantes de salud pública en países tropicales y endémicos como Colombia, pues en tanto puede ser producida por cuatro diferentes serotipos virales, durante las infecciones secundarias se presentan frecuentemente cuadros más severos que incluso pueden llevar a desenlaces fatales. El centro de la fisiopatología del dengue grave es el daño producido al endotelio, que se traduce en un aumento en la permeabilidad vascular que se evidencia como fuga plasmática, descontrol en la coagulación y daño de órganos. Aunque hay varias teorías que explican la enfermedad severa, el fenómeno denominado amplificación de la infección dependiente de anticuerpos (antibody dependent enhancement, ADE) es el más conocido. En este, se postula que el virus causante de una infección secundaria es reconocido, pero no neutralizado, por anticuerpos generados en la infección previa e internalizado en las células susceptibles usando receptores Fc-gamma, lo cual aumenta la replicación viral e induce modificaciones en la respuesta inmune celular que contribuyen al desarrollo de dengue grave. En este escrito, se realiza una revisión de los hallazgos sobre los mecanismos involucrados en el fenómeno de ADE y cómo pueden contribuir a la progresión hacia dengue grave, describiendo los conceptos de ADE extrínseco e intrínseco, además de como este fenómeno debe ser tenido en cuenta para el diseño, desarrollo e implementación de una vacuna para dengue, en tanto es capaz de afectar su eficacia y seguridad.
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17
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Dowd KA, Pierson TC. The Many Faces of a Dynamic Virion: Implications of Viral Breathing on Flavivirus Biology and Immunogenicity. Annu Rev Virol 2019; 5:185-207. [PMID: 30265634 DOI: 10.1146/annurev-virology-092917-043300] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Flaviviruses are arthropod-borne RNA viruses that are a significant threat to global health due to their widespread distribution, ability to cause severe disease in humans, and capacity for explosive spread following introduction into new regions. Members of this genus include dengue, tick-borne encephalitis, yellow fever, and Zika viruses. Vaccination has been a highly successful means to control flaviviruses, and neutralizing antibodies are an important component of a protective immune response. High-resolution structures of flavivirus structural proteins and virions, alone and in complex with antibodies, provide a detailed understanding of viral fusion mechanisms and virus-antibody interactions. However, mounting evidence suggests these structures provide only a snapshot of an otherwise structurally dynamic virus particle. The contribution of the structural ensemble arising from viral breathing to the biology, antigenicity, and immunity of flaviviruses is discussed, including implications for the development and evaluation of flavivirus vaccines.
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Affiliation(s)
- Kimberly A Dowd
- Viral Pathogenesis Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA; ,
| | - Theodore C Pierson
- Viral Pathogenesis Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA; ,
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18
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Redwan EM, AlJaddawi AA, Uversky VN. Structural disorder in the proteome and interactome of Alkhurma virus (ALKV). Cell Mol Life Sci 2019; 76:577-608. [PMID: 30443749 PMCID: PMC7079808 DOI: 10.1007/s00018-018-2968-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 10/30/2018] [Accepted: 11/05/2018] [Indexed: 12/13/2022]
Abstract
Infection by the Alkhurma virus (ALKV) leading to the Alkhurma hemorrhagic fever is a common thread in Saudi Arabia, with no efficient treatment or prevention available as of yet. Although the rational drug design traditionally uses information on known 3D structures of viral proteins, intrinsically disordered proteins (i.e., functional proteins that do not possess unique 3D structures), with their multitude of disorder-dependent functions, are crucial for the biology of viruses. Here, viruses utilize disordered regions in their invasion of the host organisms and in hijacking and repurposing of different host systems. Furthermore, the ability of viruses to efficiently adjust and accommodate to their hostile habitats is also intrinsic disorder-dependent. However, little is currently known on the level of penetrance and functional utilization of intrinsic disorder in the ALKV proteome. To fill this gap, we used here multiple computational tools to evaluate the abundance of intrinsic disorder in the ALKV genome polyprotein. We also analyzed the peculiarities of intrinsic disorder predisposition of the individual viral proteins, as well as human proteins known to be engaged in interaction with the ALKV proteins. Special attention was paid to finding a correlation between protein functionality and structural disorder. To the best of our knowledge, this work represents the first systematic study of the intrinsic disorder status of ALKV proteome and interactome.
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Affiliation(s)
- Elrashdy M Redwan
- Department of Biological Sciences, Faculty of Sciences, King Abdulaziz University, P.O. Box 80203, Jeddah, Saudi Arabia.
| | - Abdullah A AlJaddawi
- Department of Biological Sciences, Faculty of Sciences, King Abdulaziz University, P.O. Box 80203, Jeddah, Saudi Arabia
| | - Vladimir N Uversky
- Department of Biological Sciences, Faculty of Sciences, King Abdulaziz University, P.O. Box 80203, Jeddah, Saudi Arabia.
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.
- Laboratory of New Methods in Biology, Institute for Biological Instrumentation, Russian Academy of Sciences, Pushchino, 142290, Moscow Region, Russia.
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19
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Goo L, Debbink K, Kose N, Sapparapu G, Doyle MP, Wessel AW, Richner JM, Burgomaster KE, Larman BC, Dowd KA, Diamond MS, Crowe JE, Pierson TC. A protective human monoclonal antibody targeting the West Nile virus E protein preferentially recognizes mature virions. Nat Microbiol 2018; 4:71-77. [PMID: 30455471 PMCID: PMC6435290 DOI: 10.1038/s41564-018-0283-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 10/04/2018] [Indexed: 12/12/2022]
Abstract
West Nile virus (WNV), a member of the Flavivirus genus, is a leading cause of viral encephalitis in the United States1. The development of neutralizing antibodies against the flavivirus envelope (E) protein is critical for immunity and vaccine protection2. Previously identified candidate therapeutic mouse and human neutralizing monoclonal antibodies (mAbs) target epitopes within the E domain III lateral ridge and the domain I-II hinge region, respectively3. To explore the neutralizing antibody repertoire elicited by WNV infection for potential therapeutic application, we isolated 10 mAbs from WNV-infected individuals. MAb WNV-86 neutralized WNV with a 50% inhibitory concentration (IC50) of 2 ng/mL, one of the most potently neutralizing flavivirus-specific antibodies ever isolated. WNV-86 targets an epitope in E domain II, and preferentially recognizes mature virions lacking an uncleaved form of the chaperone protein prM, unlike most flavivirus-specific antibodies4. In vitro selection experiments revealed a neutralization escape mechanism involving a glycan addition to E domain II. Finally, a single dose of WNV-86 administered two days post-infection protected mice from lethal WNV challenge. This study identifies a highly potent human neutralizing mAb with therapeutic potential that targets an epitope preferentially displayed on mature virions.
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Affiliation(s)
- Leslie Goo
- Viral Pathogenesis Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.,Chan Zuckerberg Biohub, San Francisco, CA, USA
| | - Kari Debbink
- Viral Pathogenesis Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Nurgun Kose
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Gopal Sapparapu
- Department of Pediatrics, and the Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Michael P Doyle
- Department of Pathobiology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Alex W Wessel
- Departments of Medicine, Molecular Microbiology, Pathology and Immunology, and The Andrew M. and Jane M. Bursky Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St. Louis, MO, USA
| | - Justin M Richner
- Departments of Medicine, Molecular Microbiology, Pathology and Immunology, and The Andrew M. and Jane M. Bursky Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St. Louis, MO, USA.,Department of Microbiology and Immunology, University of Illinois at Chicago, Chicago, IL, USA
| | - Katherine E Burgomaster
- Viral Pathogenesis Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Bridget C Larman
- Viral Pathogenesis Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Kimberly A Dowd
- Viral Pathogenesis Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Michael S Diamond
- Departments of Medicine, Molecular Microbiology, Pathology and Immunology, and The Andrew M. and Jane M. Bursky Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St. Louis, MO, USA
| | - James E Crowe
- Departments of Pediatrics, Pathobiology, Microbiology and Immunology, and the Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, USA.
| | - Theodore C Pierson
- Viral Pathogenesis Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA.
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20
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Kenney JL, Anishchenko M, Hermance M, Romo H, Chen CI, Thangamani S, Brault AC. Generation of a Lineage II Powassan Virus (Deer Tick Virus) cDNA Clone: Assessment of Flaviviral Genetic Determinants of Tick and Mosquito Vector Competence. Vector Borne Zoonotic Dis 2018; 18:371-381. [PMID: 29782238 DOI: 10.1089/vbz.2017.2224] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The Flavivirus genus comprises a diverse group of viruses that utilize a wide range of vertebrate hosts and arthropod vectors. The genus includes viruses that are transmitted solely by mosquitoes or vertebrate hosts as well as viruses that alternate transmission between mosquitoes or ticks and vertebrates. Nevertheless, the viral genetic determinants that dictate these unique flaviviral host and vector specificities have been poorly characterized. In this report, a cDNA clone of a flavivirus that is transmitted between ticks and vertebrates (Powassan lineage II, deer tick virus [DTV]) was generated and chimeric viruses between the mosquito/vertebrate flavivirus, West Nile virus (WNV), were constructed. These chimeric viruses expressed the prM and E genes of either WNV or DTV in the heterologous nonstructural (NS) backbone. Recombinant chimeric viruses rescued from cDNAs were characterized for their capacity to grow in vertebrate and arthropod (mosquito and tick) cells as well as for in vivo vector competence in mosquitoes and ticks. Results demonstrated that the NS elements were insufficient to impart the complete mosquito or tick growth phenotypes of parental viruses; however, these NS genetic elements did contribute to a 100- and 100,000-fold increase in viral growth in vitro in tick and mosquito cells, respectively. Mosquito competence was observed only with parental WNV, while infection and transmission potential by ticks were observed with both DTV and WNV-prME/DTV chimeric viruses. These data indicate that NS genetic elements play a significant, but not exclusive, role for vector usage of mosquito- and tick-borne flaviviruses.
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Affiliation(s)
- Joan L Kenney
- 1 Division of Vector-Borne Diseases, Centers for Disease Control and Prevention , Fort Collins, Colorado
| | - Michael Anishchenko
- 1 Division of Vector-Borne Diseases, Centers for Disease Control and Prevention , Fort Collins, Colorado
| | - Meghan Hermance
- 2 Department of Pathology, Institute for Human Infections and Immunity, University of Texas Medical Branch , Galveston, Texas
| | - Hannah Romo
- 1 Division of Vector-Borne Diseases, Centers for Disease Control and Prevention , Fort Collins, Colorado
| | - Ching-I Chen
- 3 Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California , Davis, Davis, California
| | - Saravanan Thangamani
- 2 Department of Pathology, Institute for Human Infections and Immunity, University of Texas Medical Branch , Galveston, Texas
| | - Aaron C Brault
- 1 Division of Vector-Borne Diseases, Centers for Disease Control and Prevention , Fort Collins, Colorado
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21
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Wang B, Thurmond S, Hai R, Song J. Structure and function of Zika virus NS5 protein: perspectives for drug design. Cell Mol Life Sci 2018; 75:1723-1736. [PMID: 29423529 PMCID: PMC5911220 DOI: 10.1007/s00018-018-2751-x] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 01/02/2018] [Accepted: 01/11/2018] [Indexed: 12/29/2022]
Abstract
Zika virus (ZIKV) belongs to the positive-sense single-stranded RNA-containing Flaviviridae family. Its recent outbreak and association with human diseases (e.g. neurological disorders) have raised global health concerns, and an urgency to develop a therapeutic strategy against ZIKV infection. However, there is no currently approved antiviral against ZIKV. Here we present a comprehensive overview on recent progress in structure-function investigation of ZIKV NS5 protein, the largest non-structural protein of ZIKV, which is responsible for replication of the viral genome, RNA capping and suppression of host interferon responses. Structural comparison of the N-terminal methyltransferase domain and C-terminal RNA-dependent RNA polymerase domain of ZIKV NS5 with their counterparts from related viruses provides mechanistic insights into ZIKV NS5-mediated RNA replication, and identifies residues critical for its enzymatic activities. Finally, a collection of recently identified small molecule inhibitors against ZIKV NS5 or its closely related flavivirus homologues are also discussed.
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Affiliation(s)
- Boxiao Wang
- Department of Biochemistry, University of California, Riverside, CA, 92521, USA
| | - Stephanie Thurmond
- Department of Microbiology and Plant Pathology , University of California, Riverside, CA, 92521, USA
| | - Rong Hai
- Department of Microbiology and Plant Pathology , University of California, Riverside, CA, 92521, USA.
| | - Jikui Song
- Department of Biochemistry, University of California, Riverside, CA, 92521, USA.
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22
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Barrows NJ, Campos RK, Liao KC, Prasanth KR, Soto-Acosta R, Yeh SC, Schott-Lerner G, Pompon J, Sessions OM, Bradrick SS, Garcia-Blanco MA. Biochemistry and Molecular Biology of Flaviviruses. Chem Rev 2018; 118:4448-4482. [PMID: 29652486 DOI: 10.1021/acs.chemrev.7b00719] [Citation(s) in RCA: 189] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Flaviviruses, such as dengue, Japanese encephalitis, tick-borne encephalitis, West Nile, yellow fever, and Zika viruses, are critically important human pathogens that sicken a staggeringly high number of humans every year. Most of these pathogens are transmitted by mosquitos, and not surprisingly, as the earth warms and human populations grow and move, their geographic reach is increasing. Flaviviruses are simple RNA-protein machines that carry out protein synthesis, genome replication, and virion packaging in close association with cellular lipid membranes. In this review, we examine the molecular biology of flaviviruses touching on the structure and function of viral components and how these interact with host factors. The latter are functionally divided into pro-viral and antiviral factors, both of which, not surprisingly, include many RNA binding proteins. In the interface between the virus and the hosts we highlight the role of a noncoding RNA produced by flaviviruses to impair antiviral host immune responses. Throughout the review, we highlight areas of intense investigation, or a need for it, and potential targets and tools to consider in the important battle against pathogenic flaviviruses.
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Affiliation(s)
- Nicholas J Barrows
- Department of Biochemistry and Molecular Biology , University of Texas Medical Branch , Galveston , Texas 77555 , United States.,Department of Molecular Genetics and Microbiology , Duke University , Durham , North Carolina 27710 , United States
| | - Rafael K Campos
- Department of Biochemistry and Molecular Biology , University of Texas Medical Branch , Galveston , Texas 77555 , United States.,Department of Molecular Genetics and Microbiology , Duke University , Durham , North Carolina 27710 , United States
| | - Kuo-Chieh Liao
- Programme in Emerging Infectious Diseases , Duke-NUS Medical School , Singapore 169857 , Singapore
| | - K Reddisiva Prasanth
- Department of Biochemistry and Molecular Biology , University of Texas Medical Branch , Galveston , Texas 77555 , United States
| | - Ruben Soto-Acosta
- Department of Biochemistry and Molecular Biology , University of Texas Medical Branch , Galveston , Texas 77555 , United States
| | - Shih-Chia Yeh
- Programme in Emerging Infectious Diseases , Duke-NUS Medical School , Singapore 169857 , Singapore
| | - Geraldine Schott-Lerner
- Department of Biochemistry and Molecular Biology , University of Texas Medical Branch , Galveston , Texas 77555 , United States
| | - Julien Pompon
- Programme in Emerging Infectious Diseases , Duke-NUS Medical School , Singapore 169857 , Singapore.,MIVEGEC, IRD, CNRS, Université de Montpellier , Montpellier 34090 , France
| | - October M Sessions
- Programme in Emerging Infectious Diseases , Duke-NUS Medical School , Singapore 169857 , Singapore
| | - Shelton S Bradrick
- Department of Biochemistry and Molecular Biology , University of Texas Medical Branch , Galveston , Texas 77555 , United States
| | - Mariano A Garcia-Blanco
- Department of Biochemistry and Molecular Biology , University of Texas Medical Branch , Galveston , Texas 77555 , United States.,Programme in Emerging Infectious Diseases , Duke-NUS Medical School , Singapore 169857 , Singapore
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23
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Abstract
For several decades, flow cytometry has been a common approach to analyze cells and sort them to near-purity. It enables one to probe inner cellular molecules, surface receptors, or infected cells. However, the analysis of smaller entities such as viruses and exocytic vesicles has been more difficult but is becoming mainstream. This has in part been due to the development of new instrumentation with resolutions below that of conventional cytometers. It is also attributed to the several means employed to fluorescently label viruses, hence enabling them to stand out from similarly sized particles representing background noise. Thus far, more than a dozen different viruses ranging in size from 40 nm to giant viruses have been probed by this approach, which was recently dubbed "flow virometry." These studies have collectively highlighted the breadth of the applications of this method, which, for example, has elucidated the maturation of dengue virus, served as quality control for vaccinia vaccines, and enabled the sorting of herpes simplex virus discrete viral particles. The present review focuses on the means employed to characterize and sort viruses by this powerful technology and on the emerging uses of flow virometry. It similarly addresses some of its current challenges and limitations.
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24
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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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Goo L, DeMaso CR, Pelc RS, Ledgerwood JE, Graham BS, Kuhn RJ, Pierson TC. The Zika virus envelope protein glycan loop regulates virion antigenicity. Virology 2018; 515:191-202. [PMID: 29304471 DOI: 10.1016/j.virol.2017.12.032] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 12/22/2017] [Accepted: 12/26/2017] [Indexed: 01/30/2023]
Abstract
Because antibodies are an important component of flavivirus immunity, understanding the antigenic structure of flaviviruses is critical. Compared to dengue virus (DENV), the loop containing the single N-linked glycosylation site on Zika virus (ZIKV) envelope (E) proteins extends further towards the DII fusion loop (DII-FL) on neighboring E proteins within E dimers on mature viruses. Although ZIKV is poorly neutralized by DII-FL antibodies, we demonstrated significantly increased neutralization sensitivity of ZIKV particles incorporating the DENV glycan loop. Increased neutralization sensitivity was independent of E protein glycosylation: ZIKV lacking E protein glycans remained poorly neutralized, whereas ZIKV loop chimeras with or without an E protein glycan were potently neutralized. ZIKV particles lacking the E protein glycan were capable of infecting Raji cells expressing the lectin DC-SIGNR, suggesting the prM glycan of partially mature particles can facilitate entry. Our study provides insight into the determinants of ZIKV E protein function and antigenicity.
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Affiliation(s)
- Leslie Goo
- Viral Pathogenesis Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States of America
| | - Christina R DeMaso
- Viral Pathogenesis Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States of America
| | - Rebecca S Pelc
- Viral Pathogenesis Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States of America
| | - Julie E Ledgerwood
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Barney S Graham
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Richard J Kuhn
- Markey Center for Structural Biology and Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN, USA
| | - Theodore C Pierson
- Viral Pathogenesis Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States of America.
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Chew MF, Poh KS, Poh CL. Peptides as Therapeutic Agents for Dengue Virus. Int J Med Sci 2017; 14:1342-1359. [PMID: 29200948 PMCID: PMC5707751 DOI: 10.7150/ijms.21875] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 09/01/2017] [Indexed: 12/19/2022] Open
Abstract
Dengue is an important global threat caused by dengue virus (DENV) that records an estimated 390 million infections annually. Despite the availability of CYD-TDV as a commercial vaccine, its long-term efficacy against all four dengue virus serotypes remains unsatisfactory. There is therefore an urgent need for the development of antiviral drugs for the treatment of dengue. Peptide was once a neglected choice of medical treatment but it has lately regained interest from the pharmaceutical industry following pioneering advancements in technology. In this review, the design of peptide drugs, antiviral activities and mechanisms of peptides and peptidomimetics (modified peptides) action against dengue virus are discussed. The development of peptides as inhibitors for viral entry, replication and translation is also described, with a focus on the three main targets, namely, the host cell receptors, viral structural proteins and viral non-structural proteins. The antiviral peptides designed based on these approaches may lead to the discovery of novel anti-DENV therapeutics that can treat dengue patients.
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Affiliation(s)
- Miaw-Fang Chew
- Research Centre for Biomedical Sciences, Sunway University, Bandar Sunway, Selangor 47500, Malaysia
| | - Keat-Seong Poh
- Department of Surgery, Faculty of Medicine, University of Malaya, Jalan Universiti, Kuala Lumpur, 50603, Malaysia
| | - Chit-Laa Poh
- Research Centre for Biomedical Sciences, Sunway University, Bandar Sunway, Selangor 47500, Malaysia
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Goo L, VanBlargan LA, Dowd KA, Diamond MS, Pierson TC. A single mutation in the envelope protein modulates flavivirus antigenicity, stability, and pathogenesis. PLoS Pathog 2017; 13:e1006178. [PMID: 28207910 PMCID: PMC5312798 DOI: 10.1371/journal.ppat.1006178] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 01/11/2017] [Indexed: 01/23/2023] Open
Abstract
The structural flexibility or ‘breathing’ of the envelope (E) protein of flaviviruses allows virions to sample an ensemble of conformations at equilibrium. The molecular basis and functional consequences of virus conformational dynamics are poorly understood. Here, we identified a single mutation at residue 198 (T198F) of the West Nile virus (WNV) E protein domain I-II hinge that regulates virus breathing. The T198F mutation resulted in a ~70-fold increase in sensitivity to neutralization by a monoclonal antibody targeting a cryptic epitope in the fusion loop. Increased exposure of this otherwise poorly accessible fusion loop epitope was accompanied by reduced virus stability in solution at physiological temperatures. Introduction of a mutation at the analogous residue of dengue virus (DENV), but not Zika virus (ZIKV), E protein also increased accessibility of the cryptic fusion loop epitope and decreased virus stability in solution, suggesting that this residue modulates the structural ensembles sampled by distinct flaviviruses at equilibrium in a context dependent manner. Although the T198F mutation did not substantially impair WNV growth kinetics in vitro, studies in mice revealed attenuation of WNV T198F infection. Overall, our study provides insight into the molecular basis and the in vitro and in vivo consequences of flavivirus breathing. Flaviviruses include emerging pathogens such as WNV, DENV, and ZIKV that threaten global health. Despite causing significant morbidity, effective vaccines or therapeutic agents to protect humans against many flaviviruses are lacking. Because of the importance of antibodies in flavivirus immunity and vaccine protection, much effort is focused on understanding the factors that modulate antibody recognition of flaviviruses. Virus breathing, which allows viruses to sample different conformations at equilibrium, has the potential to transiently expose otherwise inaccessible antibody epitopes. Here, we report the identification a single mutation in the envelope protein that alters the exposure of a poorly accessible epitope and the stability of both WNV and DENV through changes in the ensemble of structures sampled by the virus. For WNV, this change attenuated infection and pathogenesis in mice, suggesting that virus conformational dynamics have relevant consequences in vivo.
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Affiliation(s)
- Leslie Goo
- Viral Pathogenesis Section, National Institutes of Health, Bethesda, MD, United States of America
| | - Laura A. VanBlargan
- Departments of Medicine, Molecular Microbiology, Pathology & Immunology, and The Andrew M. and Jane M. Bursky Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St. Louis, MO, United States of America
| | - Kimberly A. Dowd
- Viral Pathogenesis Section, National Institutes of Health, Bethesda, MD, United States of America
| | - Michael S. Diamond
- Departments of Medicine, Molecular Microbiology, Pathology & Immunology, and The Andrew M. and Jane M. Bursky Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St. Louis, MO, United States of America
| | - Theodore C. Pierson
- Viral Pathogenesis Section, National Institutes of Health, Bethesda, MD, United States of America
- * E-mail:
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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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Abstract
The re-emergence of Zika virus (ZIKV) and its suspected link with various disorders in newborns and adults led the World Health Organization to declare a global health emergency. In response, the stem cell field quickly established platforms for modeling ZIKV exposure using human pluripotent stem cell-derived neural progenitors and brain organoids, fetal tissues, and animal models. These efforts provided significant insight into cellular targets, pathogenesis, and underlying biological mechanisms of ZIKV infection as well as platforms for drug testing. Here we review the remarkable progress in stem cell-based ZIKV research and discuss current challenges and future opportunities.
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Affiliation(s)
- Guo-Li Ming
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Hengli Tang
- Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
| | - Hongjun Song
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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Deconstructing the Antiviral Neutralizing-Antibody Response: Implications for Vaccine Development and Immunity. Microbiol Mol Biol Rev 2016; 80:989-1010. [PMID: 27784796 DOI: 10.1128/mmbr.00024-15] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The antibody response plays a key role in protection against viral infections. While antiviral antibodies may reduce the viral burden via several mechanisms, the ability to directly inhibit (neutralize) infection of cells has been extensively studied. Eliciting a neutralizing-antibody response is a goal of many vaccine development programs and commonly correlates with protection from disease. Considerable insights into the mechanisms of neutralization have been gained from studies of monoclonal antibodies, yet the individual contributions and dynamics of the repertoire of circulating antibody specificities elicited by infection and vaccination are poorly understood on the functional and molecular levels. Neutralizing antibodies with the most protective functionalities may be a rare component of a polyclonal, pathogen-specific antibody response, further complicating efforts to identify the elements of a protective immune response. This review discusses advances in deconstructing polyclonal antibody responses to flavivirus infection or vaccination. Our discussions draw comparisons to HIV-1, a virus with a distinct structure and replication cycle for which the antibody response has been extensively investigated. Progress toward deconstructing and understanding the components of polyclonal antibody responses identifies new targets and challenges for vaccination strategies.
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Systematic Bioinformatic Approach for Prediction of Linear B-Cell Epitopes on Dengue E and prM Protein. Adv Bioinformatics 2016; 2016:1373157. [PMID: 27688753 PMCID: PMC5023840 DOI: 10.1155/2016/1373157] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 06/06/2016] [Accepted: 06/23/2016] [Indexed: 11/26/2022] Open
Abstract
B-cell epitopes on the envelope (E) and premembrane (prM) proteins of dengue virus (DENV) were predicted using bioinformatics tools, BepiPred, Ellipro, and SVMTriP. Predicted epitopes, 32 and 17 for E and prM proteins, respectively, were then characterized for their level of conservations. The epitopes, EP4/E (48–55), epitope number 4 of E protein at amino acids 48–55, EP9/E (165–182), EP11/E (218–233), EP20/E (322–349), EP21/E (326–353), EP23/E (356–365), and EP25/E (380–386), showed a high intraserotype conservancy with very low pan-serotype conservancy, demonstrating a potential target as serotype specific diagnostic markers. EP3 (30–41) located in domain-I and EP26/E (393–409), EP27/E (416–435), EP28/E (417–430) located in the stem region of E protein, and EP8/prM (93–112) from the prM protein have a pan-serotype conservancy higher than 70%. These epitopes indicate a potential use as universal vaccine candidates, subjected to verification of their potential in viral neutralization. EP2/E (16–21), EP5/E (62–123), EP6/E (63–89), EP19/E (310–329), and EP24/E (371–402), which have more than 50% pan-serotype conservancies, were found on E protein regions that are important in host cell attachment. Previous studies further show evidence for some of these epitopes to generate cross-reactive neutralizing antibodies, indicating their importance in antiviral strategies for DENV. This study suggests that bioinformatic approaches are attractive first line of screening for identification of linear B-cell epitopes.
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Zicari S, Arakelyan A, Fitzgerald W, Zaitseva E, Chernomordik LV, Margolis L, Grivel JC. Evaluation of the maturation of individual Dengue virions with flow virometry. Virology 2015; 488:20-7. [PMID: 26590794 DOI: 10.1016/j.virol.2015.10.021] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 08/18/2015] [Accepted: 10/21/2015] [Indexed: 12/20/2022]
Abstract
High-throughput techniques are needed to analyze individual virions to understand how viral heterogeneity translates into pathogenesis since in bulk analysis the individual characteristics of virions are lost. Individual Dengue virions (DENV) undergo a maturation that involves a proteolytic cleavage of prM precursor into virion-associated M protein. Here, using a new nanoparticle-based technology, "flow virometry", we compared the maturation of individual DENV produced by BHK-21 and LoVo cells. The latter lacks the furin-protease that mediates prM cleavage. We found that prM is present on about 50% of DENV particles produced in BHK-21 cells and about 85% of DENV virions produced in LoVo, indicating an increase in the fraction of not fully matured virions. Flow virometry allows us to quantify the number of fully mature particles in DENV preparations and proves to be a useful method for studying heterogeneity of the surface proteins of various viruses.
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Affiliation(s)
- Sonia Zicari
- Section on Intercellular, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Anush Arakelyan
- Section on Intercellular, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Wendy Fitzgerald
- Section on Intercellular, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Elena Zaitseva
- Section on Membrane Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Leonid V Chernomordik
- Section on Membrane Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States.
| | - Leonid Margolis
- Section on Intercellular, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States.
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Meng F, Badierah RA, Almehdar HA, Redwan EM, Kurgan L, Uversky VN. Unstructural biology of the dengue virus proteins. FEBS J 2015; 282:3368-94. [DOI: 10.1111/febs.13349] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2015] [Revised: 06/01/2015] [Accepted: 06/15/2015] [Indexed: 01/02/2023]
Affiliation(s)
- Fanchi Meng
- Department of Electrical and Computer Engineering; University of Alberta; Edmonton Alberta Canada
| | - Reaid A. Badierah
- Biological Department; Faculty of Science; King Abdulaziz University; Jeddah Saudi Arabia
| | - Hussein A. Almehdar
- Biological Department; Faculty of Science; King Abdulaziz University; Jeddah Saudi Arabia
| | - Elrashdy M. Redwan
- Biological Department; Faculty of Science; King Abdulaziz University; Jeddah Saudi Arabia
- Therapeutic and Protective Proteins Laboratory; Protein Research Department; Genetic Engineering and Biotechnology Research Institute; City for Scientific Research and Technology Applications; New Borg El-Arab Alexandria Egypt
| | - Lukasz Kurgan
- Department of Electrical and Computer Engineering; University of Alberta; Edmonton Alberta Canada
| | - Vladimir N. Uversky
- Biological Department; Faculty of Science; King Abdulaziz University; Jeddah Saudi Arabia
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute; Morsani College of Medicine; University of South Florida; Tampa FL USA
- Laboratory of Structural Dynamics, Stability and Folding of Proteins; Institute of Cytology; Russian Academy of Sciences; St Petersburg Russia
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Pierson TC, Diamond MS. A game of numbers: the stoichiometry of antibody-mediated neutralization of flavivirus infection. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 129:141-66. [PMID: 25595803 DOI: 10.1016/bs.pmbts.2014.10.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The humoral response contributes to the protection against viral pathogens. Although antibodies have the potential to inhibit viral infections via several mechanisms, an ability to neutralize viruses directly may be particularly important. Neutralizing antibody titers are commonly used as predictors of protection from infection, especially in the context of vaccine responses and immunity. Despite the simplicity of the concept, how antibody binding results in virus inactivation is incompletely understood despite decades of research. Flaviviruses have been an attractive system in which to seek a structural and quantitative understanding of how antibody interactions with virions modulate infection because of the contribution of antibodies to both protection and pathogenesis. This review will present a stoichiometric model of antibody-mediated neutralization of flaviviruses and discuss how these concepts can inform the development of vaccines and antibody-based therapeutics.
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Affiliation(s)
- Theodore C Pierson
- Viral Pathogenesis Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA.
| | - Michael S Diamond
- Departments of Medicine, Molecular Microbiology, Pathology & Immunology, Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St. Louis, Missouri, USA.
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Hsieh SC, Wu YC, Zou G, Nerurkar VR, Shi PY, Wang WK. Highly conserved residues in the helical domain of dengue virus type 1 precursor membrane protein are involved in assembly, precursor membrane (prM) protein cleavage, and entry. J Biol Chem 2014; 289:33149-60. [PMID: 25326389 DOI: 10.1074/jbc.m114.610428] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The envelope and precursor membrane (prM) proteins of dengue virus (DENV) are present on the surface of immature virions. During maturation, prM protein is cleaved by furin protease into pr peptide and membrane (M) protein. Although previous studies mainly focusing on the pr region have identified several residues important for DENV replication, the functional role of M protein, particularly the α-helical domain (MH), which is predicted to undergo a large conformational change during maturation, remains largely unknown. In this study, we investigated the role of nine highly conserved MH domain residues in the replication cycle of DENV by site-directed mutagenesis in a DENV1 prME expression construct and found that alanine substitutions introduced to four highly conserved residues at the C terminus and one at the N terminus of the MH domain greatly affect the production of both virus-like particles and replicon particles. Eight of the nine alanine mutants affected the entry of replicon particles, which correlated with the impairment in prM cleavage. Moreover, seven mutants were found to have reduced prM-E interaction at low pH, which may inhibit the formation of smooth immature particles and exposure of prM cleavage site during maturation, thus contributing to inefficient prM cleavage. Taken together, these results are the first report showing that highly conserved MH domain residues, located at 20-38 amino acids downstream from the prM cleavage site, can modulate the prM cleavage, maturation of particles, and virus entry. The highly conserved nature of these residues suggests potential targets of antiviral strategy.
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Affiliation(s)
- Szu-Chia Hsieh
- From the Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii 96813 and
| | - Yi-Chieh Wu
- From the Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii 96813 and
| | - Gang Zou
- the Wadsworth Center, New York State Department of Health, Albany, New York 12208
| | - Vivek R Nerurkar
- From the Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii 96813 and
| | - Pei-Yong Shi
- the Wadsworth Center, New York State Department of Health, Albany, New York 12208
| | - Wei-Kung Wang
- From the Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii 96813 and
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Saiyasombat R, Carrillo-Tripp J, Miller WA, Bredenbeek PJ, Blitvich BJ. Substitution of the premembrane and envelope protein genes of Modoc virus with the homologous sequences of West Nile virus generates a chimeric virus that replicates in vertebrate but not mosquito cells. Virol J 2014; 11:150. [PMID: 25151534 PMCID: PMC4148964 DOI: 10.1186/1743-422x-11-150] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 08/19/2014] [Indexed: 11/23/2022] Open
Abstract
Background Most known flaviviruses, including West Nile virus (WNV), are maintained in natural transmission cycles between hematophagous arthropods and vertebrate hosts. Other flaviviruses such as Modoc virus (MODV) and Culex flavivirus (CxFV) have host ranges restricted to vertebrates and insects, respectively. The genetic elements that modulate the differential host ranges and transmission cycles of these viruses have not been identified. Methods Fusion polymerase chain reaction (PCR) was used to replace the capsid (C), premembrane (prM) and envelope (E) genes and the prM-E genes of a full-length MODV infectious cDNA clone with the corresponding regions of WNV and CxFV. Fusion products were directly transfected into baby hamster kidney-derived cells that stably express T7 RNA polymerase. At 4 days post-transfection, aliquots of each supernatant were inoculated onto vertebrate (BHK-21 and Vero) and mosquito (C6/36) cells which were then assayed for evidence of viral infection by reverse transcription-PCR, Western blot and plaque assay. Results Chimeric virus was recovered in cells transfected with the fusion product containing the prM-E genes of WNV. The virus could infect vertebrate but not mosquito cells. The in vitro replication kinetics and yields of the chimeric virus were similar to MODV but the chimeric virus produced larger plaques. Chimeric virus was not recovered in cells transfected with any of the other fusion products. Conclusions Our data indicate that genetic elements outside of the prM-E gene region of MODV condition its vertebrate-specific phenotype.
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Affiliation(s)
| | | | | | | | - Bradley J Blitvich
- Department of Veterinary Microbiology and Preventive Medicine, College of Veterinary Medicine, Iowa State University, Ames, Iowa, USA.
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Characterization of the ectodomain of the envelope protein of dengue virus type 4: expression, membrane association, secretion and particle formation in the absence of precursor membrane protein. PLoS One 2014; 9:e100641. [PMID: 24950216 PMCID: PMC4065094 DOI: 10.1371/journal.pone.0100641] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 05/29/2014] [Indexed: 01/08/2023] Open
Abstract
Background The envelope (E) of dengue virus (DENV) is the major target of neutralizing antibodies and vaccine development. After biosynthesis E protein forms a heterodimer with precursor membrane (prM) protein. Recent reports of infection enhancement by anti-prM monoclonal antibodies (mAbs) suggest anti-prM responses could be potentially harmful. Previously, we studied a series of C-terminal truncation constructs expressing DENV type 4 prM/E or E proteins and found the ectodomain of E protein alone could be recognized by all 12 mAbs tested, suggesting E protein ectodomain as a potential subunit immunogen without inducing anti-prM response. The characteristics of DENV E protein ectodomain in the absence of prM protein remains largely unknown. Methodology/Principal Findings In this study, we investigated the expression, membrane association, glycosylation pattern, secretion and particle formation of E protein ectodomain of DENV4 in the presence or absence of prM protein. E protein ectodomain associated with membrane in or beyond trans-Golgi and contained primarily complex glycans, whereas full-length E protein associated with ER membrane and contained high mannose glycans. In the absence of prM protein, E protein ectodomain can secrete as well as form particles of approximately 49 nm in diameter, as revealed by sucrose gradient ultracentrifugation with or without detergent and electron microscopy. Mutational analysis revealed that the secretion of E protein ectodomain was affected by N-linked glycosylation and could be restored by treatment with ammonia chloride. Conclusions/Significance Considering the enhancement of DENV infectivity by anti-prM antibodies, our findings provide new insights into the expression and secretion of E protein ectodomain in the absence of prM protein and contribute to future subunit vaccine design.
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Abstract
This review is a partially personal account of the discovery of virus structure and its implication for virus function. Although I have endeavored to cover all aspects of structural virology and to acknowledge relevant individuals, I know that I have favored taking examples from my own experience in telling this story. I am anxious to apologize to all those who I might have unintentionally offended by omitting their work. The first knowledge of virus structure was a result of Stanley's studies of tobacco mosaic virus (TMV) and the subsequent X-ray fiber diffraction analysis by Bernal and Fankuchen in the 1930s. At about the same time it became apparent that crystals of small RNA plant and animal viruses could diffract X-rays, demonstrating that viruses must have distinct and unique structures. More advances were made in the 1950s with the realization by Watson and Crick that viruses might have icosahedral symmetry. With the improvement of experimental and computational techniques in the 1970s, it became possible to determine the three-dimensional, near-atomic resolution structures of some small icosahedral plant and animal RNA viruses. It was a great surprise that the protecting capsids of the first virus structures to be determined had the same architecture. The capsid proteins of these viruses all had a 'jelly-roll' fold and, furthermore, the organization of the capsid protein in the virus were similar, suggesting a common ancestral virus from which many of today's viruses have evolved. By this time a more detailed structure of TMV had also been established, but both the architecture and capsid protein fold were quite different to that of the icosahedral viruses. The small icosahedral RNA virus structures were also informative of how and where cellular receptors, anti-viral compounds, and neutralizing antibodies bound to these viruses. However, larger lipid membrane enveloped viruses did not form sufficiently ordered crystals to obtain good X-ray diffraction. Starting in the 1990s, these enveloped viruses were studied by combining cryo-electron microscopy of the whole virus with X-ray crystallography of their protein components. These structures gave information on virus assembly, virus neutralization by antibodies, and virus fusion with and entry into the host cell. The same techniques were also employed in the study of complex bacteriophages that were too large to crystallize. Nevertheless, there still remained many pleomorphic, highly pathogenic viruses that lacked the icosahedral symmetry and homogeneity that had made the earlier structural investigations possible. Currently some of these viruses are starting to be studied by combining X-ray crystallography with cryo-electron tomography.
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Abstract
Japanese encephalitis (JE) is the most common form of viral encephalitis that appears in the form of frequent epidemics of brain fever throughout Southeast Asia, China and India. The disease is caused by a Flavivirus named Japanese encephalitis virus that is spread to humans by mosquitoes. An internationally approved mouse brain-derived inactivated vaccine has been available that is relatively expensive, gives immunity of uncertain duration and is not completely safe. Cell culture-derived inactivated and attenuated JE vaccines are in use in China, but these are not produced as per the norms acceptable in most countries. Several new promising JE vaccine candidates have been developed, some of which are under different stages of clinical evaluation. These new candidate JE vaccines have the potential to generate long-lasting immunity at low cost.
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Affiliation(s)
- Kaushik Bharati
- Virology laboratory, National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110 067, India.
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The flavivirus protease as a target for drug discovery. Virol Sin 2013; 28:326-36. [PMID: 24242363 DOI: 10.1007/s12250-013-3390-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Accepted: 11/01/2013] [Indexed: 01/27/2023] Open
Abstract
Many flaviviruses are significant human pathogens causing considerable disease burdens, including encephalitis and hemorrhagic fever, in the regions in which they are endemic. A paucity of treatments for flaviviral infections has driven interest in drug development targeting proteins essential to flavivirus replication, such as the viral protease. During viral replication, the flavivirus genome is translated as a single polyprotein precursor, which must be cleaved into individual proteins by a complex of the viral protease, NS3, and its cofactor, NS2B. Because this cleavage is an obligate step of the viral life-cycle, the flavivirus protease is an attractive target for antiviral drug development. In this review, we will survey recent drug development studies targeting the NS3 active site, as well as studies targeting an NS2B/NS3 interaction site determined from flavivirus protease crystal structures.
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41
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Wu Y, Zhang F, Ma W, Song J, Huang Q, Zhang H. A Plasmid Encoding Japanese Encephalitis Virus PrM and E Proteins Elicits Protective Immunity in Suckling Mice. Microbiol Immunol 2013; 48:585-90. [PMID: 15322338 DOI: 10.1111/j.1348-0421.2004.tb03555.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
A plasmid encoding Japanese encephalitis virus (JEV) prM and E proteins was constructed, and its efficacy as a candidate vaccine against JEV was evaluated in suckling mice. Groups of 10 BALB/c mice (5-7 days old) were immunized twice via muscular injection with this DNA vaccine, an empty vector or PBS at an interval of 3 weeks, and were challenged with a lethal dose of JEV 3 weeks after the second inoculation. Both cellular and humoral immune responses were examined before the challenge. Two animals from each group were sacrificed to detect the JEV-specific cytotoxic T lymphocyte activity. JEV-specific lactate dehydrogenase release in the DNA vaccine, empty vector and PBS groups was 37.5%, 18% and 8.5% respectively. JEV-specific antibody was detected in 8 of 10 animals in DNA vaccine group with a geometrical mean titer of 1: 28.3. The pooled serum from the same group also showed a neutralizing activity. Six of 8 mice in the DNA vaccine group survived the challenge, with a protection rate of 75%, but all the mice died in the two control groups. These results show that this JEV prM and E DNA vaccine is immunogenic and protective against JEV infection in the mouse model.
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MESH Headings
- Animals
- Animals, Suckling
- Antibodies, Viral/blood
- Encephalitis Virus, Japanese/genetics
- Encephalitis Virus, Japanese/immunology
- Encephalitis, Japanese/immunology
- Encephalitis, Japanese/prevention & control
- Immunization
- Japanese Encephalitis Vaccines/administration & dosage
- Japanese Encephalitis Vaccines/genetics
- Japanese Encephalitis Vaccines/immunology
- Membrane Glycoproteins/genetics
- Membrane Glycoproteins/immunology
- Mice
- Mice, Inbred BALB C
- Plasmids/genetics
- Plasmids/immunology
- T-Lymphocytes, Cytotoxic/immunology
- Vaccines, DNA/administration & dosage
- Vaccines, DNA/immunology
- Viral Envelope Proteins/genetics
- Viral Envelope Proteins/immunology
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Affiliation(s)
- Yushui Wu
- Department of Microbiology, Fourth Military Medical University, Xi'an 710032, Shaanxi Province, China
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42
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Yun SI, Lee YM. Japanese encephalitis: the virus and vaccines. Hum Vaccin Immunother 2013; 10:263-79. [PMID: 24161909 PMCID: PMC4185882 DOI: 10.4161/hv.26902] [Citation(s) in RCA: 171] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 10/14/2013] [Accepted: 10/22/2013] [Indexed: 12/11/2022] Open
Abstract
Japanese encephalitis (JE) is an infectious disease of the central nervous system caused by Japanese encephalitis virus (JEV), a zoonotic mosquito-borne flavivirus. JEV is prevalent in much of Asia and the Western Pacific, with over 4 billion people living at risk of infection. In the absence of antiviral intervention, vaccination is the only strategy to develop long-term sustainable protection against JEV infection. Over the past half-century, a mouse brain-derived inactivated vaccine has been used internationally for active immunization. To date, however, JEV is still a clinically important, emerging, and re-emerging human pathogen of global significance. In recent years, production of the mouse brain-derived vaccine has been discontinued, but 3 new cell culture-derived vaccines are available in various parts of the world. Here we review current aspects of JEV biology, summarize the 4 types of JEV vaccine, and discuss the potential of an infectious JEV cDNA technology for future vaccine development.
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Affiliation(s)
- Sang-Im Yun
- Department of Animal, Dairy, and Veterinary Sciences; Utah Science Technology and Research; College of Agriculture and Applied Sciences; Utah State University; Logan, UT USA
| | - Young-Min Lee
- Department of Animal, Dairy, and Veterinary Sciences; Utah Science Technology and Research; College of Agriculture and Applied Sciences; Utah State University; Logan, UT USA
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43
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The Fc region of an antibody impacts the neutralization of West Nile viruses in different maturation states. J Virol 2013; 87:13729-40. [PMID: 24109224 DOI: 10.1128/jvi.02340-13] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Flavivirus-infected cells secrete a structurally heterogeneous population of viruses because of an inefficient virion maturation process. Flaviviruses assemble as noninfectious, immature virions composed of trimers of envelope (E) and precursor membrane (prM) protein heterodimers. Cleavage of prM is a required process during virion maturation, although this often remains incomplete for infectious virus particles. Previous work demonstrated that the efficiency of virion maturation could impact antibody neutralization through changes in the accessibility of otherwise cryptic epitopes on the virion. In this study, we show that the neutralization potency of monoclonal antibody (MAb) E33 is sensitive to the maturation state of West Nile virus (WNV), despite its recognition of an accessible epitope, the domain III lateral ridge (DIII-LR). Comprehensive epitope mapping studies with 166 E protein DIII-LR variants revealed that the functional footprint of MAb E33 on the E protein differs subtly from that of the well-characterized DIII-LR MAb E16. Remarkably, aromatic substitutions at E protein residue 306 ablated the maturation state sensitivity of E33 IgG, and the neutralization efficacy of E33 Fab fragments was not affected by changes in the virion maturation state. We propose that E33 IgG binding on mature virions orients the Fc region in a manner that impacts subsequent antibody binding to nearby sites. This Fc-mediated steric constraint is a novel mechanism by which the maturation state of a virion modulates the efficacy of the humoral immune response to flavivirus infection.
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44
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Bäck AT, Lundkvist A. Dengue viruses - an overview. Infect Ecol Epidemiol 2013; 3:19839. [PMID: 24003364 PMCID: PMC3759171 DOI: 10.3402/iee.v3i0.19839] [Citation(s) in RCA: 143] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 07/11/2013] [Accepted: 07/16/2013] [Indexed: 12/11/2022] Open
Abstract
Dengue viruses (DENVs) cause the most common arthropod-borne viral disease in man with 50-100 million infections per year. Because of the lack of a vaccine and antiviral drugs, the sole measure of control is limiting the Aedes mosquito vectors. DENV infection can be asymptomatic or a self-limited, acute febrile disease ranging in severity. The classical form of dengue fever (DF) is characterized by high fever, headache, stomach ache, rash, myalgia, and arthralgia. Severe dengue, dengue hemorrhagic fever (DHF), and dengue shock syndrome (DSS) are accompanied by thrombocytopenia, vascular leakage, and hypotension. DSS, which can be fatal, is characterized by systemic shock. Despite intensive research, the underlying mechanisms causing severe dengue is still not well understood partly due to the lack of appropriate animal models of infection and disease. However, even though it is clear that both viral and host factors play important roles in the course of infection, a fundamental knowledge gap still remains to be filled regarding host cell tropism, crucial host immune response mechanisms, and viral markers for virulence.
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Affiliation(s)
- Anne Tuiskunen Bäck
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden ; Swedish Institute for Communicable Disease Control, Solna, Sweden ; Swedish International Development Cooperation Agency, Unit for Research Cooperation, Stockholm, Sweden
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45
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A single amino acid substitution in the core protein of West Nile virus increases resistance to acidotropic compounds. PLoS One 2013; 8:e69479. [PMID: 23874963 PMCID: PMC3715472 DOI: 10.1371/journal.pone.0069479] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 06/10/2013] [Indexed: 12/13/2022] Open
Abstract
West Nile virus (WNV) is a worldwide distributed mosquito-borne flavivirus that naturally cycles between birds and mosquitoes, although it can infect multiple vertebrate hosts including horses and humans. This virus is responsible for recurrent epidemics of febrile illness and encephalitis, and has recently become a global concern. WNV requires to transit through intracellular acidic compartments at two different steps to complete its infectious cycle. These include fusion between the viral envelope and the membrane of endosomes during viral entry, and virus maturation in the trans-Golgi network. In this study, we followed a genetic approach to study the connections between viral components and acidic pH. A WNV mutant with increased resistance to the acidotropic compound NH4Cl, which blocks organelle acidification and inhibits WNV infection, was selected. Nucleotide sequencing revealed that this mutant displayed a single amino acid substitution (Lys 3 to Glu) on the highly basic internal capsid or core (C) protein. The functional role of this replacement was confirmed by its introduction into a WNV infectious clone. This single amino acid substitution also increased resistance to other acidification inhibitor (concanamycin A) and induced a reduction of the neurovirulence in mice. Interestingly, a naturally occurring accompanying mutation found on prM protein abolished the resistant phenotype, supporting the idea of a genetic crosstalk between the internal C protein and the external glycoproteins of the virion. The findings here reported unveil a non-previously assessed connection between the C viral protein and the acidic pH necessary for entry and proper exit of flaviviruses.
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Abstract
Enveloped viruses rely on fusion proteins in their envelope to fuse the viral membrane to the host-cell membrane. This key step in viral entry delivers the viral genome into the cytoplasm for replication. Although class II fusion proteins are genetically and structurally unrelated to class I fusion proteins, they use the same physical principles and topology as other fusion proteins to drive membrane fusion. Exposure of a fusion loop first allows it to insert into the host-cell membrane. Conserved hydrophobic residues in the fusion loop act as an anchor, which penetrates only partway into the outer bilayer leaflet of the host-cell membrane. Subsequent folding back of the fusion protein on itself directs the C-terminal viral transmembrane anchor towards the fusion loop. This fold-back forces the host-cell membrane (held by the fusion loop) and the viral membrane (held by the C-terminal transmembrane anchor) against each other, resulting in membrane fusion. In class II fusion proteins, the fold-back is triggered by the reduced pH of an endosome, and is accompanied by the assembly of fusion protein monomers into trimers. The fold-back occurs by domain rearrangement rather than by an extensive refolding of secondary structure, but this domain rearrangement and the assembly of monomers into trimers together bury a large surface area. The energy that is thus released exerts a bending force on the apposed viral and cellular membranes, causing them to bend towards each other and, eventually, to fuse.
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Affiliation(s)
- Stefan Pöhlmann
- grid.10423.340000000095299877Institute for Virology, Hannover Medical School, Hannover, Germany ,grid.418215.b0000000085027018German Primate Center, Göttingen, Germany
| | - Graham Simmons
- grid.266102.10000000122976811Blood Systems Research Institute, and Department of Laboratory Medicine, University of California San Francisco, San Francisco, California USA
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47
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Yost SA, Marcotrigiano J. Viral precursor polyproteins: keys of regulation from replication to maturation. Curr Opin Virol 2013; 3:137-42. [PMID: 23602469 PMCID: PMC3660988 DOI: 10.1016/j.coviro.2013.03.009] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 03/19/2013] [Accepted: 03/20/2013] [Indexed: 11/25/2022]
Abstract
Viral polyproteins are cleaved in a spatially and temporally regulated manner. Access to the cleavage site is highly regulated through various mechanisms. Cleavage can result in structural rearrangement of the termini.
Many viruses use a replication strategy involving the translation of a large polyprotein, which is cleaved by viral and/or cellular proteases. Several of these viruses severely impact human health around the globe, including HIV, HCV, Dengue virus, and West Nile virus. This method of genome organization has many benefits to the virus such as condensation of genetic material, as well as temporal and spatial regulation of protein activity depending on polyprotein cleavage state. The study of polyprotein precursors is necessary to fully understand viral infection, and identify possible new drug targets; however, few atomic structures are currently available. Presented here are structures of four recent polyprotein precursors from viruses with a positive sense RNA genome.
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Affiliation(s)
- Samantha A Yost
- Center for Advanced Biotechnology and Medicine, Department of Chemistry and Chemical Biology, Rutgers University, 679 Hoes Lane West, Piscataway, NJ 08854, United States
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48
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C-terminal helical domains of dengue virus type 4 E protein affect the expression/stability of prM protein and conformation of prM and E proteins. PLoS One 2012; 7:e52600. [PMID: 23300717 PMCID: PMC3530441 DOI: 10.1371/journal.pone.0052600] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Accepted: 11/19/2012] [Indexed: 01/18/2023] Open
Abstract
Background The envelope (E) protein of dengue virus (DENV) is the major immunogen for dengue vaccine development. At the C-terminus are two α-helices (EH1 and EH2) and two transmembrane domains (ET1 and ET2). After synthesis, E protein forms a heterodimer with the precursor membrane (prM) protein, which has been shown as a chaperone for E protein and could prevent premature fusion of E protein during maturation. Recent reports of enhancement of DENV infectivity by anti-prM monoclonal antibodies (mAbs) suggest the presence of prM protein in dengue vaccine is potentially harmful. A better understanding of prM-E interaction and its effect on recognition of E and prM proteins by different antibodies would provide important information for future design of safe and effective subunit dengue vaccines. Methodology/Principal Findings In this study, we examined a series of C-terminal truncation constructs of DENV4 prME, E and prM. In the absence of E protein, prM protein expressed poorly. In the presence of E protein, the expression of prM protein increased in a dose-dependent manner. Radioimmunoprecipitation, sucrose gradient sedimentation and pulse-chase experiments revealed ET1 and EH2 were involved in prM-E interaction and EH2 in maintaining the stability of prM protein. Dot blot assay revealed E protein affected the recognition of prM protein by an anti-prM mAb; truncation of EH2 or EH1 affected the recognition of E protein by several anti-E mAbs, which was further verified by capture ELISA. The E protein ectodomain alone can be recognized well by all anti-E mAbs tested. Conclusions/Significance A C-terminal domain (EH2) of DENV E protein can affect the expression and stability of its chaperone prM protein. These findings not only add to our understanding of the interaction between prM and E proteins, but also suggest the ectodomain of E protein alone could be a potential subunit immunogen without inducing anti-prM response.
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50
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Immune responses to West Nile virus infection in the central nervous system. Viruses 2012; 4:3812-30. [PMID: 23247502 PMCID: PMC3528292 DOI: 10.3390/v4123812] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Revised: 12/07/2012] [Accepted: 12/10/2012] [Indexed: 12/16/2022] Open
Abstract
West Nile virus (WNV) continues to cause outbreaks of severe neuroinvasive disease in humans and other vertebrate animals in the United States, Europe, and other regions of the world. This review discusses our understanding of the interactions between virus and host that occur in the central nervous system (CNS), the outcome of which can be protection, viral pathogenesis, or immunopathogenesis. We will focus on defining the current state of knowledge of WNV entry, tropism, and host immune response in the CNS, all of which affect the balance between injury and successful clearance.
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