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Tang J, Fu M, Xu C, Xue B, Zhou A, Chen S, Zhao H, Zhou Y, Chen J, Yang Q, Chen X. Development of a novel virus-like particle-based vaccine for preventing tick-borne encephalitis virus infection. Virol Sin 2023; 38:767-777. [PMID: 37328107 PMCID: PMC10590693 DOI: 10.1016/j.virs.2023.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Accepted: 06/12/2023] [Indexed: 06/18/2023] Open
Abstract
Tick-borne encephalitis virus (TBEV) is an important tick-borne pathogen that poses as a serious public health concern. The coverage and immunogenicity of the currently available vaccines against TBEV are relatively low; therefore, it is crucial to develop novel and effective vaccines against TBEV. The present study describes a novel strategy for the assembly of virus-like particles (VLPs) by co-expressing the structural (core/prM/E) and non-structural (NS2B/NS3Pro) proteins of TBEV. The efficacy of the VLPs was subsequently evaluated in C57BL/6 mice, and the resultant IgG serum could neutralize both Far-Eastern and European subtypes of TBEV. These findings indicated that the VLP-based vaccine elicited the production of cross-subtype reactive antibodies. The VLPs provided protection to mice lacking the type I interferon receptor (IFNAR-/-) against lethal TBEV challenge, with undetectable viral load in brain and intestinal tissues. Furthermore, the group that received the VLP vaccine did not exhibit significant pathological changes and the inflammatory factors were significantly suppressed compared to the control group. Immunization with the VLP vaccine induced the production of multiple-cytokine-producing antiviral CD4+ T cells in vivo, including TNF-α+, IL-2+, and IFN-γ+ T cells. Altogether, the findings suggest that noninfectious VLPs can serve as a potentially safe and effective vaccine candidate against diverse subtypes of TBEV.
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Affiliation(s)
- Jielin Tang
- Guangzhou National Laboratory, Guangzhou, 510005, China; State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Muqing Fu
- Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China
| | - Chonghui Xu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Bao Xue
- Guangzhou National Laboratory, Guangzhou, 510005, China; State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Anqi Zhou
- GMU-GIBH Joint School of Life Sciences, Guangzhou Medical University, Guangzhou, 511436, China
| | - Sijie Chen
- GMU-GIBH Joint School of Life Sciences, Guangzhou Medical University, Guangzhou, 511436, China
| | - He Zhao
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Yuan Zhou
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China
| | - Jizheng Chen
- Guangzhou National Laboratory, Guangzhou, 510005, China; State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China; State Key Laboratory of Respiratory Disease, Guangzhou Medical University, Guangzhou, 511436, China
| | - Qi Yang
- Guangzhou National Laboratory, Guangzhou, 510005, China; State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China.
| | - Xinwen Chen
- Guangzhou National Laboratory, Guangzhou, 510005, China; State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, China; State Key Laboratory of Respiratory Disease, Guangzhou Medical University, Guangzhou, 511436, China.
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Bollman B, Nunna N, Bahl K, Hsiao CJ, Bennett H, Butler S, Foreman B, Burgomaster KE, Aleshnick M, Kong WP, Fisher BE, Ruckwardt TJ, Morabito KM, Graham BS, Dowd KA, Pierson TC, Carfi A. An optimized messenger RNA vaccine candidate protects non-human primates from Zika virus infection. NPJ Vaccines 2023; 8:58. [PMID: 37080988 PMCID: PMC10119314 DOI: 10.1038/s41541-023-00656-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 03/29/2023] [Indexed: 04/22/2023] Open
Abstract
Zika virus (ZIKV), an arbovirus transmitted by mosquitoes, was identified as a cause of congenital disease during a major outbreak in the Americas in 2016. Vaccine design strategies relied on limited available isolate sequence information due to the rapid response necessary. The first-generation ZIKV mRNA vaccine, mRNA-1325, was initially generated and, as additional strain sequences became available, a second mRNA vaccine, mRNA-1893, was developed. Herein, we compared the immune responses following mRNA-1325 and mRNA-1893 vaccination and reported that mRNA-1893 generated comparable neutralizing antibody titers to mRNA-1325 at 1/20th of the dose and provided complete protection from ZIKV challenge in non-human primates. In-depth characterization of these vaccines indicated that the observed immunologic differences could be attributed to a single amino acid residue difference that compromised mRNA-1325 virus-like particle formation.
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Affiliation(s)
| | | | | | | | | | | | - Bryant Foreman
- Viral Pathogenesis Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Katherine E Burgomaster
- Viral Pathogenesis Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Maya Aleshnick
- Viral Pathogenesis Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Wing-Pui Kong
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Brian E Fisher
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Tracy J Ruckwardt
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Kaitlyn M Morabito
- 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
| | - Kimberly A Dowd
- Viral Pathogenesis Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Theodore C Pierson
- Viral Pathogenesis Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
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Alzahrani N, Wu MJ, Sousa CF, Kalinina OV, Welsch C, Yi M. SPCS1-Dependent E2-p7 processing determines HCV Assembly efficiency. PLoS Pathog 2022; 18:e1010310. [PMID: 35130329 PMCID: PMC8853643 DOI: 10.1371/journal.ppat.1010310] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 02/17/2022] [Accepted: 01/26/2022] [Indexed: 11/18/2022] Open
Abstract
Recent studies identified signal peptidase complex subunit 1 (SPCS1) as a proviral host factor for Flaviviridae viruses, including HCV. One of the SPCS1’s roles in flavivirus propagation was attributed to its regulation of signal peptidase complex (SPC)-mediated processing of flavivirus polyprotein, especially C-prM junction. However, whether SPCS1 also regulates any SPC-mediated processing sites within HCV polyprotein remains unclear. In this study, we determined that loss of SPCS1 specifically impairs the HCV E2-p7 processing by the SPC. We also determined that efficient separation of E2 and p7, regardless of its dependence on SPC-mediated processing, leads to SPCS1 dispensable for HCV assembly These results suggest that SPCS1 regulates HCV assembly by facilitating the SPC-mediated processing of E2-p7 precursor. Structural modeling suggests that intrinsically delayed processing of the E2-p7 is likely caused by the structural rigidity of p7 N-terminal transmembrane helix-1 (p7/TM1/helix-1), which has mostly maintained membrane-embedded conformations during molecular dynamics (MD) simulations. E2-p7-processing-impairing p7 mutations narrowed the p7/TM1/helix-1 bending angle against the membrane, resulting in closer membrane embedment of the p7/TM1/helix-1 and less access of E2-p7 junction substrate to the catalytic site of the SPC, located well above the membrane in the ER lumen. Based on these results we propose that the key mechanism of action of SPCS1 in HCV assembly is to facilitate the E2-p7 processing by enhancing the E2-p7 junction site presentation to the SPC active site. By providing evidence that SPCS1 facilitates HCV assembly by regulating SPC-mediated cleavage of E2-p7 junction, equivalent to the previously established role of this protein in C-prM junction processing in flavivirus, this study establishes the common role of SPCS1 in Flaviviridae family virus propagation as to exquisitely regulate the SPC-mediated processing of specific, suboptimal target sites.
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Affiliation(s)
- Nabeel Alzahrani
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
| | - Ming-Jhan Wu
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
| | - Carla F. Sousa
- Drug Bioinformatics Group, HIPS, HZI, Saarbrücken, Germany
| | - Olga V. Kalinina
- Drug Bioinformatics Group, HIPS, HZI, Saarbrücken, Germany
- Medical Faculty, Saarland University, Homburg, Germany
| | - Christoph Welsch
- Department of Internal Medicine 1, Goethe University Hospital, Frankfurt am Main, Germany
| | - MinKyung Yi
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, Galveston, Texas, United States of America
- * E-mail:
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Wahaab A, Mustafa BE, Hameed M, Stevenson NJ, Anwar MN, Liu K, Wei J, Qiu Y, Ma Z. Potential Role of Flavivirus NS2B-NS3 Proteases in Viral Pathogenesis and Anti-flavivirus Drug Discovery Employing Animal Cells and Models: A Review. Viruses 2021; 14:44. [PMID: 35062249 PMCID: PMC8781031 DOI: 10.3390/v14010044] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 12/22/2021] [Accepted: 12/23/2021] [Indexed: 02/07/2023] Open
Abstract
Flaviviruses are known to cause a variety of diseases in humans in different parts of the world. There are very limited numbers of antivirals to combat flavivirus infection, and therefore new drug targets must be explored. The flavivirus NS2B-NS3 proteases are responsible for the cleavage of the flavivirus polyprotein, which is necessary for productive viral infection and for causing clinical infections; therefore, they are a promising drug target for devising novel drugs against different flaviviruses. This review highlights the structural details of the NS2B-NS3 proteases of different flaviviruses, and also describes potential antiviral drugs that can interfere with the viral protease activity, as determined by various studies. Moreover, optimized in vitro reaction conditions for studying the NS2B-NS3 proteases of different flaviviruses may vary and have been incorporated in this review. The increasing availability of the in silico and crystallographic/structural details of flavivirus NS2B-NS3 proteases in free and drug-bound states can pave the path for the development of promising antiflavivirus drugs to be used in clinics. However, there is a paucity of information available on using animal cells and models for studying flavivirus NS2B-NS3 proteases, as well as on the testing of the antiviral drug efficacy against NS2B-NS3 proteases. Therefore, on the basis of recent studies, an effort has also been made to propose potential cellular and animal models for the study of flavivirus NS2B-NS3 proteases for the purposes of exploring flavivirus pathogenesis and for testing the efficacy of possible drugs targets, in vitro and in vivo.
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Affiliation(s)
- Abdul Wahaab
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China; (A.W.); (M.H.); (M.N.A.); (K.L.); (J.W.)
| | - Bahar E Mustafa
- Sub Campus Toba Tek Singh, University of Agriculture, Faisalabad 36050, Pakistan;
| | - Muddassar Hameed
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China; (A.W.); (M.H.); (M.N.A.); (K.L.); (J.W.)
- Department of Biomedical Sciences and Pathobiology, College of Veterinary Medicine, Virginia Polytechnic Institute, State University, Fralin Life Sciences Building, 360 W Campus Blacksburg, Blacksburg, VA 24061, USA
| | - Nigel J. Stevenson
- Royal College of Surgeons in Ireland, Medical University of Bahrain, Busaiteen, Adliya 15503, Bahrain;
- Viral Immunology Group, School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, D02 R590 Dublin, Ireland
| | - Muhammad Naveed Anwar
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China; (A.W.); (M.H.); (M.N.A.); (K.L.); (J.W.)
| | - Ke Liu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China; (A.W.); (M.H.); (M.N.A.); (K.L.); (J.W.)
| | - Jianchao Wei
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China; (A.W.); (M.H.); (M.N.A.); (K.L.); (J.W.)
| | - Yafeng Qiu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China; (A.W.); (M.H.); (M.N.A.); (K.L.); (J.W.)
| | - Zhiyong Ma
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China; (A.W.); (M.H.); (M.N.A.); (K.L.); (J.W.)
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The E rns Carboxyterminus: Much More Than a Membrane Anchor. Viruses 2021; 13:v13071203. [PMID: 34201636 PMCID: PMC8310223 DOI: 10.3390/v13071203] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 06/15/2021] [Accepted: 06/17/2021] [Indexed: 12/12/2022] Open
Abstract
Pestiviruses express the unique essential envelope protein Erns, which exhibits RNase activity, is attached to membranes by a long amphipathic helix, and is partially secreted from infected cells. The RNase activity of Erns is directly connected with pestivirus virulence. Formation of homodimers and secretion of the protein are hypothesized to be important for its role as a virulence factor, which impairs the host's innate immune response to pestivirus infection. The unusual membrane anchor of Erns raises questions with regard to proteolytic processing of the viral polyprotein at the Erns carboxy-terminus. Moreover, the membrane anchor is crucial for establishing the critical equilibrium between retention and secretion and ensures intracellular accumulation of the protein at the site of virus budding so that it is available to serve both as structural component of the virion and factor controlling host immune reactions. In the present manuscript, we summarize published as well as new data on the molecular features of Erns including aspects of its interplay with the other two envelope proteins with a special focus on the biochemistry of the Erns membrane anchor.
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Lee WHK, Liu W, Fan JS, Yang D. Dengue virus protease activity modulated by dynamics of protease cofactor. Biophys J 2021; 120:2444-2453. [PMID: 33894215 DOI: 10.1016/j.bpj.2021.04.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 03/26/2021] [Accepted: 04/02/2021] [Indexed: 10/21/2022] Open
Abstract
The viral protease domain (NS3pro) of dengue virus is essential for virus replication, and its cofactor NS2B is indispensable for the proteolytic function. Although several NS3pro-NS2B complex structures have been obtained, the dynamic property of the complex remains poorly understood. Using NMR relaxation techniques, here we found that NS3pro-NS2B exists in both closed and open conformations that are in dynamic equilibrium on a submillisecond timescale in aqueous solution. Our structural information indicates that the C-terminal region of NS2B is disordered in the minor open conformation but folded in the major closed conformation. Using mutagenesis, we showed that the closed-open conformational equilibrium can be shifted by changing NS2B stability. Moreover, we revealed that the proteolytic activity of NS3pro-NS2B correlates well with the population of the closed conformation. Our results suggest that the closed-open conformational equilibrium can be used by both nature and humanity to control the replication of dengue virus.
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Affiliation(s)
- Wen Hao Kenneth Lee
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Wei Liu
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Jing-Song Fan
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Daiwen Yang
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore.
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Xie S, Zhang H, Liang Z, Yang X, Cao R. AXL, an Important Host Factor for DENV and ZIKV Replication. Front Cell Infect Microbiol 2021; 11:575346. [PMID: 33954117 PMCID: PMC8092360 DOI: 10.3389/fcimb.2021.575346] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 02/18/2021] [Indexed: 12/13/2022] Open
Abstract
Flaviviruses, as critically important pathogens, are still major public health problems all over the world. For instance, the evolution of ZIKV led to large-scale outbreaks in the Yap island in 2007. DENV was considered by the World Health Organization (WHO) as one of the 10 threats to global health in 2019. Enveloped viruses hijack a variety of host factors to complete its replication cycle. Phosphatidylserine (PS) receptor, AXL, is considered to be a candidate receptor for flavivirus invasion. In this review, we discuss the molecular structure of ZIKV and DENV, and how they interact with AXL to successfully invade host cells. A more comprehensive understanding of the molecular mechanisms of flavivirus-AXL interaction will provide crucial insights into the virus infection process and the development of anti-flavivirus therapeutics.
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Affiliation(s)
- Shengda Xie
- Ministry of Education (MOE) Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Huiru Zhang
- Ministry of Education (MOE) Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Zhenjie Liang
- Ministry of Education (MOE) Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Xingmiao Yang
- Ministry of Education (MOE) Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Ruibing Cao
- Ministry of Education (MOE) Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
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Downstream Sequences Control the Processing of the Pestivirus E rns-E1 Precursor. J Virol 2020; 95:JVI.01905-20. [PMID: 33028718 DOI: 10.1128/jvi.01905-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 09/30/2020] [Indexed: 02/06/2023] Open
Abstract
Like other enveloped viruses, pestiviruses employ cellular proteases for processing of their structural proteins. While typical signal peptidase cleavage motifs are present at the carboxy terminus of the signal sequence preceding Erns and the E1/E2 and E2/P7 sites, the Erns-E1 precursor is cleaved by signal peptidase at a highly unusual structure, in which the transmembrane sequence upstream of the cleavage site is replaced by an amphipathic helix. As shown before, the integrity of the amphipathic helix is crucial for efficient processing. The data presented here demonstrate that the E1 sequence downstream of this cleavage site is also important for the cleavage. Carboxy-terminal truncation of the E1 moiety as well as internal deletions in E1 reduced the cleavage efficiency to less than 30% of the wild-type (wt) level. Moreover, the C-terminal truncation by more than 30 amino acids resulted in strong secretion of the uncleaved fusion proteins. The reduced processing and increased secretion were even observed when 10 to 5 amino-terminal residues of E1 were left, whereas extensions by 1 or 3 E1 residues resulted in reduced processing but no significantly increased secretion. In contrast to the E1 sequences, a 10-amino-acid c-myc tag fused to the Erns C terminus had only marginal effect on secretion but was also not processed efficiently. Mutation of the von Heijne sequence upstream of E2 not only blocked the cleavage between E1 and E2 but also prevented the processing between Erns and E2. Thus, processing at the Erns-E1 site is a highly regulated process.IMPORTANCE Cellular signal peptidase (SPase) cleavage represents an important step in maturation of viral envelope proteins. Fine tuning of this system allows for establishment of concerted folding and processing processes in different enveloped viruses. We report here on SPase processing of the Erns-E1-E2 glycoprotein precursor of pestiviruses. Erns-E1 cleavage is delayed and only executed efficiently when the complete E1 sequence is present. C-terminal truncation of the Erns-E1 precursor impairs processing and leads to significant secretion of the protein. The latter is not detected when internal deletions preserving the E1 carboxy terminus are introduced, but also these constructs show impaired processing. Moreover, Erns-E1 is only processed after cleavage at the E1/E2 site. Thus, processing of the pestiviral glycoprotein precursor by SPase is done in an ordered way and depends on the integrity of the proteins for efficient cleavage. The functional importance of this processing scheme is discussed in the paper.
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Alzahrani N, Wu MJ, Shanmugam S, Yi M. Delayed by Design: Role of Suboptimal Signal Peptidase Processing of Viral Structural Protein Precursors in Flaviviridae Virus Assembly. Viruses 2020; 12:v12101090. [PMID: 32993149 PMCID: PMC7601889 DOI: 10.3390/v12101090] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 09/04/2020] [Accepted: 09/24/2020] [Indexed: 02/06/2023] Open
Abstract
The Flaviviridae virus family is classified into four different genera, including flavivirus, hepacivirus, pegivirus, and pestivirus, which cause significant morbidity and mortality in humans and other mammals, including ruminants and pigs. These are enveloped, single-stranded RNA viruses sharing a similar genome organization and replication scheme with certain unique features that differentiate them. All viruses in this family express a single polyprotein that encodes structural and nonstructural proteins at the N- and C-terminal regions, respectively. In general, the host signal peptidase cleaves the structural protein junction sites, while virus-encoded proteases process the nonstructural polyprotein region. It is known that signal peptidase processing is a rapid, co-translational event. Interestingly, certain signal peptidase processing site(s) in different Flaviviridae viral structural protein precursors display suboptimal cleavage kinetics. This review focuses on the recent progress regarding the Flaviviridae virus genus-specific mechanisms to downregulate signal peptidase-mediated processing at particular viral polyprotein junction sites and the role of delayed processing at these sites in infectious virus particle assembly.
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Diosa-Toro M, Prasanth KR, Bradrick SS, Garcia Blanco MA. Role of RNA-binding proteins during the late stages of Flavivirus replication cycle. Virol J 2020; 17:60. [PMID: 32334603 PMCID: PMC7183730 DOI: 10.1186/s12985-020-01329-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 04/11/2020] [Indexed: 12/21/2022] Open
Abstract
The genus Flavivirus encompasses several worldwide-distributed arthropod-borne viruses including, dengue virus, Japanese encephalitis virus, West Nile virus, yellow fever virus, Zika virus, and tick-borne encephalitis virus. Infection with these viruses manifest with symptoms ranging from febrile illness to life- threatening hypotensive shock and encephalitis. Therefore, flaviviruses pose a great risk to public health. Currently, preventive measures are falling short to control epidemics and there are no antivirals against any Flavivirus.Flaviviruses carry a single stranded positive-sense RNA genome that plays multiple roles in infected cells: it is translated into viral proteins, used as template for genome replication, it is the precursor of the subgenomic flaviviral RNA and it is assembled into new virions. Furthermore, viral RNA genomes are also packaged into extracellular vesicles, e.g. exosomes, which represent an alternate mode of virus dissemination.Because RNA molecules are at the center of Flavivirus replication cycle, viral and host RNA-binding proteins (RBPs) are critical determinants of infection. Numerous studies have revealed the function of RBPs during Flavivirus infection, particularly at the level of RNA translation and replication. These proteins, however, are also critical participants at the late stages of the replication cycle. Here we revise the function of host RBPs and the viral proteins capsid, NS2A and NS3, during the packaging of viral RNA and the assembly of new virus particles. Furthermore, we go through the evidence pointing towards the importance of host RBPs in mediating cellular RNA export with the idea that the biogenesis of exosomes harboring Flavivirus RNA would follow an analogous pathway.
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Affiliation(s)
- Mayra Diosa-Toro
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore.
| | - K Reddisiva Prasanth
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA
| | - Shelton S Bradrick
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA
- Global Health, Surveillance & Diagnostics Group, MRIGlobal, Kansas City, MO, USA
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, USA
| | - Mariano A Garcia Blanco
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore.
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA.
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, USA.
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Virus Like Particles (VLP) as multivalent vaccine candidate against Chikungunya, Japanese Encephalitis, Yellow Fever and Zika Virus. Sci Rep 2020; 10:4017. [PMID: 32132648 PMCID: PMC7055223 DOI: 10.1038/s41598-020-61103-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 02/10/2020] [Indexed: 12/31/2022] Open
Abstract
Mosquito borne viral diseases are an emerging threat as evident from the recent outbreak of Zika virus (ZIKV) as well as repeated outbreaks of Chikungunya (CHIKV), Yellow fever (YFV) and Japanese encephalitis (JEV) virus in different geographical regions. These four arboviruses are endemic in overlapping regions due to the co-prevalence of the transmitting mosquito vector species Aedes and Culex. Thus, a multivalent vaccine that targets all four viruses would be of benefit to regions of the world where these diseases are endemic. We developed a potential Virus Like Particle (VLP) based multivalent vaccine candidate to target these diseases by using stable cell lines that continuously secrete VLPs in the culture supernatants. Moreover, inclusion of Capsid in the VLPs provides an additional viral protein leading to an enhanced immune response as evident from our previous studies with ZIKV. Immunization of Balb/c mice with different combinations of Capsid protein containing VLPs either as monovalent, bivalent or tetravalent formulation resulted in generation of high levels of neutralizing antibodies. Interestingly, the potential tetravalent VLP vaccine candidate provided strong neutralizing antibody titers against all four viruses. The 293 T stable cell lines secreting VLPs were adapted to grow in suspension cultures to facilitate vaccine scale up. Our stable cell lines secreting individual VLPs provide a flexible yet scalable platform conveniently adaptable to different geographical regions as per the need. Further studies in appropriate animal models will be needed to define the efficacy of the multivalent vaccine candidate to protect against lethal virus challenge.
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Sangiambut S, Pethrak C, Anupap C, Ninnabkaew P, Kongsanthia C, Promphet N, Chaiyaloom S, Songjaeng A, Avirutnan P, Puttikhunt C, Kasinrerk W, Sittisombut N, Malasit P. Enhanced production of infectious particles by adaptive modulation of C–prM processing and C–C interaction during propagation of dengue pseudoinfectious virus in stable CprME-expressing cells. J Gen Virol 2020; 101:59-72. [DOI: 10.1099/jgv.0.001345] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Sutha Sangiambut
- Division of Dengue Hemorrhagic Fever Research, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
- Medical Biotechnology Research Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Bangkok 12120, Thailand
| | - Chatpong Pethrak
- Division of Dengue Hemorrhagic Fever Research, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
- Medical Biotechnology Research Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Bangkok 12120, Thailand
| | - Chainarong Anupap
- Division of Dengue Hemorrhagic Fever Research, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Parichat Ninnabkaew
- Division of Dengue Hemorrhagic Fever Research, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Charuphan Kongsanthia
- Division of Dengue Hemorrhagic Fever Research, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Natcha Promphet
- Division of Dengue Hemorrhagic Fever Research, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
- Medical Biotechnology Research Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Bangkok 12120, Thailand
| | - Suwipa Chaiyaloom
- Division of Dengue Hemorrhagic Fever Research, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
- Medical Biotechnology Research Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Bangkok 12120, Thailand
| | - Adisak Songjaeng
- Division of Dengue Hemorrhagic Fever Research, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Panisadee Avirutnan
- Division of Dengue Hemorrhagic Fever Research, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Chunya Puttikhunt
- Division of Dengue Hemorrhagic Fever Research, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
- Medical Biotechnology Research Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Bangkok 12120, Thailand
| | - Watchara Kasinrerk
- Division of Clinical Immunology, Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai 50200, Thailand
- Biomedical Technology Research Center, National Center for Genetic Engineering and Biotechnology, National Sciences and Technology Development Agency at the Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai, Thailand
| | - Nopporn Sittisombut
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
- Medical Biotechnology Research Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Bangkok 12120, Thailand
| | - Prida Malasit
- Division of Dengue Hemorrhagic Fever Research, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
- Medical Biotechnology Research Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Bangkok 12120, Thailand
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Rana J, Burrone OR. DENV2 Pseudoviral Particles with Unprocessed Capsid Protein Are Assembled and Infectious. Viruses 2019; 12:v12010027. [PMID: 31881703 PMCID: PMC7019998 DOI: 10.3390/v12010027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 12/06/2019] [Accepted: 12/23/2019] [Indexed: 11/16/2022] Open
Abstract
Proteolytic processing of flavivirus polyprotein is a uniquely controlled process. To date, the sequential cleavage of the capsid anchor sequence at the junction of C-PrM has been considered essential for the production of flaviviruses. In this study, we used two experimental approaches to show the effect of unprocessed capsid on the production and infectivity of dengue virus 2 (DENV2) pseudoviral particles. The results showed that (1) both mature and unprocessed capsids of DENV2 were equally efficient in the viral RNA packaging and also in the assembly of infective particles; (2) DENV2 variants, in which the viral and host mediated cleavage of Ca peptide were independent, produced significantly higher levels of infective particles. Overall, this study demonstrated that unlike other flaviviruses, DENV2 capsid does not require a cleavable Ca sequence, and the sequential cleavage is not an obligatory requirement for the morphogenesis of infective pseudoviral particles.
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Affiliation(s)
- Jyoti Rana
- Correspondence: (J.R.); (O.R.B.); Tel.: +39-040-3757314 (J.R. & O.R.B.)
| | - Oscar R. Burrone
- Correspondence: (J.R.); (O.R.B.); Tel.: +39-040-3757314 (J.R. & O.R.B.)
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14
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Rana J, Slon Campos JL, Poggianella M, Burrone OR. Dengue virus capsid anchor modulates the efficiency of polyprotein processing and assembly of viral particles. J Gen Virol 2019; 100:1663-1673. [DOI: 10.1099/jgv.0.001346] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The assembly and secretion of flaviviruses are part of an elegantly regulated process. During maturation, the viral polyprotein undergoes several co- and post-translational cleavages mediated by both viral and host proteases. Among these, sequential cleavage at the N and C termini of the hydrophobic capsid anchor (Ca) is crucial in deciding the fate of viral infection. Here, using a refined dengue pseudovirus production system, along with cleavage and furin inhibition assays, immunoblotting and secondary structure prediction analysis, we show that Ca plays a key role in the processing efficiency of dengue virus type 2 (DENV2) structural proteins and viral particle assembly. Replacement of the DENV2 Ca with the homologous regions from West nile or Zika viruses or, alternatively, increasing its length, improved cleavage and hence particle assembly. Further, we showed that substitution of the Ca conserved proline residue (P110) to alanine abolishes pseudovirus production, regardless of the Ca sequence length. Besides providing the results of a biochemical analysis of DENV2 structural polyprotein processing, this study also presents a system for efficient production of dengue pseudoviruses.
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Affiliation(s)
- Jyoti Rana
- Present address: Gene and Cell Therapy group, IU School of Medicine, Wells Center of Pediatric Research, IUPUI, Indianapolis, IN 46202, USA
- International Centre for Genetic Engineering and Biotechnology, ICGEB, Padriciano 99, 34149 Trieste, Italy
| | - José Luis Slon Campos
- Present address: Nuffield Department of Medicine, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN, UK
- International Centre for Genetic Engineering and Biotechnology, ICGEB, Padriciano 99, 34149 Trieste, Italy
| | - Monica Poggianella
- International Centre for Genetic Engineering and Biotechnology, ICGEB, Padriciano 99, 34149 Trieste, Italy
| | - Oscar R. Burrone
- International Centre for Genetic Engineering and Biotechnology, ICGEB, Padriciano 99, 34149 Trieste, Italy
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15
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Xing H, Xu S, Jia F, Yang Y, Xu C, Qin C, Shi L. Zika NS2B is a crucial factor recruiting NS3 to the ER and activating its protease activity. Virus Res 2019; 275:197793. [PMID: 31676367 DOI: 10.1016/j.virusres.2019.197793] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 10/18/2019] [Accepted: 10/22/2019] [Indexed: 01/10/2023]
Abstract
Zika virus (ZIKV) is an emergent flavivirus associated with severe neurological disorders. ZIKV NS3 protein is a viral protease that cleaves the ZIKV polyprotein precursor into individual viral proteins. In this study, we found that ZIKV NS3 by itself exhibited mitochondrial localization, which was quite different from its endoplasmic reticulum (ER) localization in ZIKV-infected cells. We screened viral proteins and identified NS2B as the bona fide recruiter of NS3 to the ER. The NS2B C-terminal tail interacted with NS3 protease domain to retain NS3 on the ER. β-Sheet motifs that formed between NS2B and the NS3 protease domain played important roles in their interaction, while mutation in the β-strand of NS2B attenuated NS2B-NS3 interaction and impaired the ability of NS3 protease to cleave the polyprotein precursor into multiple viral proteins. Consequently, NS2B mutations led to severe inhibition of ZIKV replication and production due to insufficient NS3 protease activity. In summary, our study reveals the critical role of NS2B in NS3 recruitment and protease function and provides mechanistic insight into ZIKV replication.
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Affiliation(s)
- Huaipeng Xing
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, Beijing, 100005, China; Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, Beijing, 100005, China
| | - Shan Xu
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, Beijing, 100005, China; Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, Beijing, 100005, China
| | - Fangfei Jia
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, Beijing, 100005, China; Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, Beijing, 100005, China
| | - Yang Yang
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, Beijing, 100005, China; Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, Beijing, 100005, China
| | - Caimin Xu
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, Beijing, 100005, China; Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, Beijing, 100005, China
| | - Chengfeng Qin
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, 100005, China.
| | - Lei Shi
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, Beijing, 100005, China; Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, Beijing, 100005, China.
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16
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Garg H, Mehmetoglu-Gurbuz T, Ruddy GM, Joshi A. Capsid containing virus like particle vaccine against Zika virus made from a stable cell line. Vaccine 2019; 37:7123-7131. [PMID: 31607605 DOI: 10.1016/j.vaccine.2019.09.093] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 09/26/2019] [Accepted: 09/27/2019] [Indexed: 12/16/2022]
Abstract
Zika virus infection during pregnancy is associated with severe birth defects including microcephaly in the new born. The lack of specific treatment calls for the development of a safe and effective vaccine for use in pregnant women. We recently tested the efficacy of a Virus Like Particle (VLP) vaccine for Zika virus in mice and found that Capsid-preMembrane-Env (CprME) VLPs generated a better neutralizing antibody response than preMembrane-Env (prME) VLPs. The superiority of CprME VLPs suggested that inclusion of capsid in the vaccine may enhance the immune response. However, production of CprME VLPs requires co-expression of NS2B-3 protease, which creates a major hurdle for generation of stable cell lines. To overcome this limitation, we generated a bicistronic vector that expresses CprME and NS2B-3 using an IRES sequence. This bicistronic expression cassette, in a lentiviral vector, was used to create a stable cell line that constitutively secretes CprME VLPs. The expression of NS2B-3, presence of capsid in the secreted VLPs, efficiency of VLP release, and stability of the cell line was extensively tested. Antigen sparing studies in mice using prME and CprME VLPs, both derived from stable cell lines, confirmed the superiority of CprME VLPs in generation of neutralizing antibody response. Capsid specific antibodies were detected in CprME VLP immunized mice providing mechanistic insights into the superiority of these VLPs. Challenge of CprME VLP immunized mice with Zika PRVABC59 showed complete protection against day 3 viremia further validating the efficacy of the vaccine. Our study is the first to generate a stable cell line secreting Zika CprME VLPs via natural NS2B-3 cleavage, demonstrate incorporation of capsid in CprME VLPs and complete protection in challenge studies. This is a major advancement for the Zika vaccine platform that is safe for use in pregnant women and readily scalable for use in developing countries.
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Affiliation(s)
- Himanshu Garg
- Center of Emphasis in Infectious Diseases, Department of Molecular and Translational Medicine, Texas Tech University Health Sciences Center, El Paso, TX, USA.
| | - Tugba Mehmetoglu-Gurbuz
- Center of Emphasis in Infectious Diseases, Department of Molecular and Translational Medicine, Texas Tech University Health Sciences Center, El Paso, TX, USA
| | - Gregory M Ruddy
- Center of Emphasis in Infectious Diseases, Department of Molecular and Translational Medicine, Texas Tech University Health Sciences Center, El Paso, TX, USA
| | - Anjali Joshi
- Center of Emphasis in Infectious Diseases, Department of Molecular and Translational Medicine, Texas Tech University Health Sciences Center, El Paso, TX, USA.
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17
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Mazeaud C, Freppel W, Chatel-Chaix L. The Multiples Fates of the Flavivirus RNA Genome During Pathogenesis. Front Genet 2018. [PMID: 30564270 DOI: 10.3389/fgene.2018.00595/full] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023] Open
Abstract
The Flavivirus genus comprises many viruses (including dengue, Zika, West Nile and yellow fever viruses) which constitute important public health concerns worldwide. For several of these pathogens, neither antivirals nor vaccines are currently available. In addition to this unmet medical need, flaviviruses are of particular interest since they constitute an excellent model for the study of spatiotemporal regulation of RNA metabolism. Indeed, with no DNA intermediate or nuclear step, the flaviviral life cycle entirely relies on the cytoplasmic fate of a single RNA species, namely the genomic viral RNA (vRNA) which contains all the genetic information necessary for optimal viral replication. From a single open reading frame, the vRNA encodes a polyprotein which is processed to generate the mature viral proteins. In addition to coding for the viral polyprotein, the vRNA serves as a template for RNA synthesis and is also selectively packaged into newly assembled viral particles. Notably, vRNA translation, replication and encapsidation must be tightly coordinated in time and space via a fine-tuned equilibrium as these processes cannot occur simultaneously and hence, are mutually exclusive. As such, these dynamic processes involve several vRNA secondary and tertiary structures as well as RNA modifications. Finally, the vRNA can be detected as a foreign molecule by cytosolic sensors which trigger upon activation antiviral signaling pathways and the production of antiviral factors such as interferons and interferon-stimulated genes. However, to create an environment favorable to infection, flaviviruses have evolved mechanisms to dampen these antiviral processes, notably through the production of a specific vRNA degradation product termed subgenomic flavivirus RNA (sfRNA). In this review, we discuss the current understanding of the fates of flavivirus vRNA and how this is regulated at the molecular level to achieve an optimal replication within infected cells.
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Affiliation(s)
- Clément Mazeaud
- Institut National de la Recherche Scientifique, Centre INRS-Institut Armand-Frappier, Laval, QC, Canada
| | - Wesley Freppel
- Institut National de la Recherche Scientifique, Centre INRS-Institut Armand-Frappier, Laval, QC, Canada
| | - Laurent Chatel-Chaix
- Institut National de la Recherche Scientifique, Centre INRS-Institut Armand-Frappier, Laval, QC, Canada
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18
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Mazeaud C, Freppel W, Chatel-Chaix L. The Multiples Fates of the Flavivirus RNA Genome During Pathogenesis. Front Genet 2018; 9:595. [PMID: 30564270 PMCID: PMC6288177 DOI: 10.3389/fgene.2018.00595] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 11/15/2018] [Indexed: 12/11/2022] Open
Abstract
The Flavivirus genus comprises many viruses (including dengue, Zika, West Nile and yellow fever viruses) which constitute important public health concerns worldwide. For several of these pathogens, neither antivirals nor vaccines are currently available. In addition to this unmet medical need, flaviviruses are of particular interest since they constitute an excellent model for the study of spatiotemporal regulation of RNA metabolism. Indeed, with no DNA intermediate or nuclear step, the flaviviral life cycle entirely relies on the cytoplasmic fate of a single RNA species, namely the genomic viral RNA (vRNA) which contains all the genetic information necessary for optimal viral replication. From a single open reading frame, the vRNA encodes a polyprotein which is processed to generate the mature viral proteins. In addition to coding for the viral polyprotein, the vRNA serves as a template for RNA synthesis and is also selectively packaged into newly assembled viral particles. Notably, vRNA translation, replication and encapsidation must be tightly coordinated in time and space via a fine-tuned equilibrium as these processes cannot occur simultaneously and hence, are mutually exclusive. As such, these dynamic processes involve several vRNA secondary and tertiary structures as well as RNA modifications. Finally, the vRNA can be detected as a foreign molecule by cytosolic sensors which trigger upon activation antiviral signaling pathways and the production of antiviral factors such as interferons and interferon-stimulated genes. However, to create an environment favorable to infection, flaviviruses have evolved mechanisms to dampen these antiviral processes, notably through the production of a specific vRNA degradation product termed subgenomic flavivirus RNA (sfRNA). In this review, we discuss the current understanding of the fates of flavivirus vRNA and how this is regulated at the molecular level to achieve an optimal replication within infected cells.
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Affiliation(s)
- Clément Mazeaud
- Institut National de la Recherche Scientifique, Centre INRS-Institut Armand-Frappier, Laval, QC, Canada
| | - Wesley Freppel
- Institut National de la Recherche Scientifique, Centre INRS-Institut Armand-Frappier, Laval, QC, Canada
| | - Laurent Chatel-Chaix
- Institut National de la Recherche Scientifique, Centre INRS-Institut Armand-Frappier, Laval, QC, Canada
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Garg H, Mehmetoglu-Gurbuz T, Joshi A. Recent Advances in Zika Virus Vaccines. Viruses 2018; 10:v10110631. [PMID: 30441757 PMCID: PMC6267279 DOI: 10.3390/v10110631] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 11/08/2018] [Accepted: 11/11/2018] [Indexed: 01/07/2023] Open
Abstract
The recent outbreaks of Zika virus (ZIKV) infections and associated microcephaly in newborns has resulted in an unprecedented effort by researchers to target this virus. Significant advances have been made in developing vaccine candidates, treatment strategies and diagnostic assays in a relatively short period of time. Being a preventable disease, the first line of defense against ZIKV would be to vaccinate the highly susceptible target population, especially pregnant women. Along those lines, several vaccine candidates including purified inactivated virus (PIV), live attenuated virus (LAV), virus like particles (VLP), DNA, modified RNA, viral vectors and subunit vaccines have been in the pipeline with several advancing to clinical trials. As the primary objective of Zika vaccination is the prevention of vertical transmission of the virus to the unborn fetus, the safety and efficacy requirements for this vaccine remain unique when compared to other diseases. This review will discuss these recent advances in the field of Zika vaccine development.
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Affiliation(s)
- Himanshu Garg
- Center of Emphasis in Infectious Diseases, Department of Biomedical Science, Texas Tech University Health Sciences Center, El Paso, TX 79905, USA.
| | - Tugba Mehmetoglu-Gurbuz
- Center of Emphasis in Infectious Diseases, Department of Biomedical Science, Texas Tech University Health Sciences Center, El Paso, TX 79905, USA.
| | - Anjali Joshi
- Center of Emphasis in Infectious Diseases, Department of Biomedical Science, Texas Tech University Health Sciences Center, El Paso, TX 79905, USA.
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20
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Role of Capsid Anchor in the Morphogenesis of Zika Virus. J Virol 2018; 92:JVI.01174-18. [PMID: 30158295 DOI: 10.1128/jvi.01174-18] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 08/22/2018] [Indexed: 01/24/2023] Open
Abstract
The flavivirus capsid protein (C) is separated from the downstream premembrane (PrM) protein by a hydrophobic sequence named capsid anchor (Ca). During polyprotein processing, Ca is sequentially cleaved by the viral NS2B/NS3 protease on the cytosolic side and by signal peptidase on the luminal side of the endoplasmic reticulum (ER). To date, Ca is considered important mostly for directing translocation of PrM into the ER lumen. In this study, the role of Ca in the assembly and secretion of Zika virus was investigated using a pseudovirus-based approach. Our results show that, while Ca-mediated anchoring of C to the ER membrane is not needed for the production of infective particles, Ca expression in cis with respect to PrM is strictly required to allow proper assembly of infectious particles. Finally, we show that the presence of heterologous, but not homologous, Ca induces degradation of E through the autophagy/lysosomal pathway.IMPORTANCE The capsid anchor (Ca) is a single-pass transmembrane domain at the C terminus of the capsid protein (C) known to function as a signal for the translocation of PrM into the ER lumen. The objective of this study was to further examine the role of Ca in Zika virus life cycle, whether involved in the formation of nucleocapsid through association with C or in the formation of viral envelope. In this study, we show that Ca has a function beyond the one of translocation signal, controlling protein E stability and therefore its availability for assembly of infectious particles.
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21
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Slonchak A, Khromykh AA. Subgenomic flaviviral RNAs: What do we know after the first decade of research. Antiviral Res 2018; 159:13-25. [PMID: 30217649 DOI: 10.1016/j.antiviral.2018.09.006] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 09/10/2018] [Accepted: 09/10/2018] [Indexed: 12/13/2022]
Abstract
The common feature of flaviviral infection is the accumulation of abundant virus-derived noncoding RNA, named flaviviral subgenomic RNA (sfRNA) in infected cells. This RNA represents a product of incomplete degradation of viral genomic RNA by the cellular 5'-3' exoribonuclease XRN1 that stalls at the conserved highly structured elements in the 3' untranslated region (UTR). This mechanism of sfRNA generation was discovered a decade ago and since then sfRNA has been a focus of intense research. The ability of flaviviruses to produce sfRNA was shown to be evolutionary conserved in all members of Flavivirus genus. Mutations in the 3'UTR that affect production of sfRNAs and their interactions with host factors showed that sfRNAs are responsible for viral pathogenicity, host adaptation, and emergence of new pathogenic strains. RNA structural elements required for XRN1 stalling have been elucidated and the role of sfRNAs in inhibiting host antiviral responses in arthropod and vertebrate hosts has been demonstrated. Some molecular mechanisms determining these properties of sfRNA have been recently characterized, while other aspects of sfRNA functions remain an open avenue for future research. In this review we summarise the current state of knowledge on the mechanisms of generation and functional roles of sfRNAs in the life cycle of flaviviruses and highlight the gaps in our knowledge to be addressed in the future.
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Affiliation(s)
- Andrii Slonchak
- The Australian Infectious Disease Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, 4072, Australia
| | - Alexander A Khromykh
- The Australian Infectious Disease Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, QLD, 4072, Australia.
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22
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Early Events in Japanese Encephalitis Virus Infection: Viral Entry. Pathogens 2018; 7:pathogens7030068. [PMID: 30104482 PMCID: PMC6161159 DOI: 10.3390/pathogens7030068] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 07/31/2018] [Accepted: 08/06/2018] [Indexed: 12/15/2022] Open
Abstract
Japanese encephalitis virus (JEV), a mosquito-borne zoonotic flavivirus, is an enveloped positive-strand RNA virus that can cause a spectrum of clinical manifestations, ranging from mild febrile illness to severe neuroinvasive disease. Today, several killed and live vaccines are available in different parts of the globe for use in humans to prevent JEV-induced diseases, yet no antivirals are available to treat JEV-associated diseases. Despite the progress made in vaccine research and development, JEV is still a major public health problem in southern, eastern, and southeastern Asia, as well as northern Oceania, with the potential to become an emerging global pathogen. In viral replication, the entry of JEV into the cell is the first step in a cascade of complex interactions between the virus and target cells that is required for the initiation, dissemination, and maintenance of infection. Because this step determines cell/tissue tropism and pathogenesis, it is a promising target for antiviral therapy. JEV entry is mediated by the viral glycoprotein E, which binds virions to the cell surface (attachment), delivers them to endosomes (endocytosis), and catalyzes the fusion between the viral and endosomal membranes (membrane fusion), followed by the release of the viral genome into the cytoplasm (uncoating). In this multistep process, a collection of host factors are involved. In this review, we summarize the current knowledge on the viral and cellular components involved in JEV entry into host cells, with an emphasis on the initial virus-host cell interactions on the cell surface.
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23
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Peng M, Swarbrick CMD, Chan KWK, Luo D, Zhang W, Lai X, Li G, Vasudevan SG. Luteolin escape mutants of dengue virus map to prM and NS2B and reveal viral plasticity during maturation. Antiviral Res 2018; 154:87-96. [PMID: 29665375 DOI: 10.1016/j.antiviral.2018.04.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 04/10/2018] [Accepted: 04/13/2018] [Indexed: 10/17/2022]
Abstract
We previously showed that luteolin, a well-known plant-derived component found in the "heat clearing" class of Traditional Chinese Medicine (TCM) herbs, is an uncompetitive inhibitor (Ki 58.6 μM) of the host proprotein convertase furin, an endoprotease that is required for maturation of flaviviruses in the trans-Golgi compartment. Luteolin also weakly inhibited recombinant dengue virus NS2B/NS3 protease (Ki 140.36 μM) non-competitively. In order to further explore the mechanism of inhibition we isolated resistant mutants by continuous passaging of DENV2 in the presence of increasing concentrations of luteolin. Nucleotide sequence analysis of the luteolin-resistant escape mutants revealed nucleotide changes that lead to amino acid substitutions in the prM (T79R) and NS2B (I114M) genes. These mutations were introduced into a DENV2 infectious clone and tested for replication in Huh-7 cells. Interestingly we found that the replication kinetics of prM T19R-NS2B I114M double-mutant (DM) was similar to wild-type virus (WT). On the other hand the prM T79R single mutant (SM1) was attenuated and the NS2B I114M single mutant (SM2) showed enhanced replication. Time of drug addition assay with luteolin showed that the mutant viruses were able to produce more mature virions than WT in the order DM > SM2>SM1>WT. Exogenous addition of furin to purified immature WT or mutant viruses revealed that luteolin blocked the prM cleavage of WT and SM2 at a similar level. On the other hand the SM1 immature virus showed some cleavage while the DM immature virus revealed efficient furin cleavage of prM even in the presence of 50 μM luteolin. Our findings suggest that luteolin inhibition of furin may occur at host/pathogen interface that permits the virus to escape the suppression by mutating key residue that may lead to an altered interface.
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Affiliation(s)
- Minhua Peng
- Program in Emerging Infectious Disease, Duke-NUS Medical School, 8 College Road, Singapore 169857, Singapore; Mathematical Engineering Academy of Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510006, China
| | | | - Kitti Wing-Ki Chan
- Program in Emerging Infectious Disease, Duke-NUS Medical School, 8 College Road, Singapore 169857, Singapore; Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore
| | - Dahai Luo
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 636921, Singapore
| | - Wei Zhang
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, China
| | - Xiaoping Lai
- Mathematical Engineering Academy of Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510006, China
| | - Geng Li
- Center for Animal Experiment, Guangzhou University of Chinese Medicine, Guangzhou 510405, China
| | - Subhash G Vasudevan
- Program in Emerging Infectious Disease, Duke-NUS Medical School, 8 College Road, Singapore 169857, Singapore; Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore.
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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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The Transactions of NS3 and NS5 in Flaviviral RNA Replication. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1062:147-163. [PMID: 29845531 DOI: 10.1007/978-981-10-8727-1_11] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Dengue virus (DENV) replication occurs in virus-induced vesicles that contain the replication complex (RC) where viral RNA, viral proteins and host proteins participate in RNA-RNA, RNA-protein and protein-protein interactions to ensure viral genome synthesis. However, the details of the multitude of interactions involved in the biogenesis of the infectious virion are not fully understood. In this review, we will focus on the interaction between non-structural (NS) proteins NS3 and NS5, as well as their interactions with viral RNA and briefly also the interaction of NS5 with the host nuclear transport receptor protein importin-α. The multifunctional NS3 protease/helicase and NS5 methyltransferase (MTase)/RNA-dependent RNA polymerase (RdRp) contain all the enzymatic activities required to synthesize the viral RNA genome. The success stories of drug discovery and development with Hepatitis C virus (HCV), a member of the Flaviviridae family, has led to the view that DENV NS3 and NS5 may be attractive antiviral drug targets. However, more than 10 years of intensive research effort by Novatis has revealed that they are not "low hanging fruits" and therefore, the search for potent directly acting antivirals (DAAs) remains a pipeline goal for several medium to large drug discovery enterprises. The effort to discover DAAs for DENV has been boosted by the epidemic outbreak of the closely related flavivirus member - Zika virus (ZIKV). Because the viral RNA replication occurs within a molecular machine that is composed several viral and host proteins, much interest has turned to characterising functionally essential protein-protein interactions in order to identify potential allosteric inhibitor binding sites within the RC.
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Abstract
West Nile virus (WNV) is an arbovirus with increased global incidence in the last decade. It is also a major cause of human encephalitis in the USA. WNV is an arthropod-transmitted virus that mainly affects birds but humans become infected as incidental dead-end hosts which can cause outbreaks in naïve populations. The main vectors of WNV are mosquitoes of the genus Culex, which preferentially feed on birds. As in many other arboviruses, the characteristics that allow Flaviviruses like WNV to replicate and transmit to different hosts are encrypted in their genome, which also contains information for the production of structural and nonstructural proteins needed for host cell infection. WNV and other Flaviviruses have developed different strategies to establish infection, replication, and successful transmission. Most of these strategies include the diversion of the host's immune responses away from the virus. In this review, we describe the molecular structure and protein function of WNV with emphasis on protein involvement in the modulation of antiviral immune responses.
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Javed F, Manzoor KN, Ali M, Haq IU, Khan AA, Zaib A, Manzoor S. Zika virus: what we need to know? J Basic Microbiol 2017; 58:3-16. [DOI: 10.1002/jobm.201700398] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Revised: 09/19/2017] [Accepted: 09/03/2017] [Indexed: 01/22/2023]
Affiliation(s)
- Farakh Javed
- Department of Microbiology; University of Haripur; Haripur Pakistan
| | | | - Mubashar Ali
- Department of Microbiology; University of Haripur; Haripur Pakistan
| | - Irshad U. Haq
- Department of Microbiology; University of Haripur; Haripur Pakistan
| | - Abid A. Khan
- Department of Biosciences; COMSATS Institute of Information Technology; Islamabad Pakistan
| | - Assad Zaib
- Department of Medical Lab Technology; University of Haripur; Haripur Pakistan
| | - Sobia Manzoor
- Atta-ur-Rehman School of Applied Bio-Sciences; National University of Science and Technology; Islamabad Pakistan
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Investigating Tick-borne Flaviviral-like Particles as a Delivery System for Gene Therapy. Curr Ther Res Clin Exp 2017; 88:8-17. [PMID: 30093925 PMCID: PMC6076373 DOI: 10.1016/j.curtheres.2017.10.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/10/2017] [Indexed: 12/30/2022] Open
Abstract
Background Research on the biogenesis of tick-borne encephalitis virus (TBEV) would benefit gene therapy. Due to specific arrangements of genes along the TBEV genome, its viral-like particles (VLPs) could be exploited as shuttles to deliver their replicon, which carries therapeutic genes, to immune system cells. Objective To develop a flaviviral vector for gene delivery as a part of gene therapy research that can be expressed in secretable VLP suicidal shuttles and provide abundant unique molecular and structural data supporting this gene therapy concept. Method TBEV structural gene constructs of a Swedish Torö strain were cloned into plasmids driven by the promoters CAG and CMV and then transfected into various cell lines, including COS-1 and BHK-21. Time-course sampling of the cells, culture fluid, cell lysate supernatant, and pellet specimens were performed. Western blotting and electron microscopy analyses of collected specimens were used to investigate molecular and structural processing of TBEV structural proteins. Results Western blotting analysis showed differences between promoters in directing the gene expression of the VLPs constructs. The premature flaviviral polypeptides as well as mature VLPs could be traced. Using electron microscopy, the premature and mature VLP accumulation in cellular compartments—and also endoplasmic reticulum proliferation as a virus factory platform—were observed in addition to secreted VLPs. Conclusions The abundant virologic and cellular findings in this study show the natural processing and safety of inserting flaviviral structural genes into suicidal VLP shuttles. Thus, we propose that these VLPs are a suitable gene delivering system model in gene therapy.
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29
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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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30
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Development of Virus-Like-Particle Vaccine and Reporter Assay for Zika Virus. J Virol 2017; 91:JVI.00834-17. [PMID: 28794019 DOI: 10.1128/jvi.00834-17] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 07/31/2017] [Indexed: 12/31/2022] Open
Abstract
Recent worldwide outbreaks of Zika virus (ZIKV) infection and the lack of an approved vaccine raise serious concerns regarding preparedness to combat this emerging virus. We used a virus-like particle (VLP)-based approach to develop a vaccine and a microneutralization assay for ZIKV. A synthetic capsid-premembrane-envelope (C-prM-E) gene construct of ZIKV was used to generate reporter virus particles (RVPs) that package a green fluorescent protein (GFP) reporter-expressing West Nile virus (WNV) replicon. The assay was adapted to a 96-well format, similar to the plaque reduction neutralization test (PRNT), and showed high reproducibility with specific detection of ZIKV neutralizing antibodies. Furthermore, C-prM-E and prM-E VLPs were tested as vaccine candidates in mice and compared to DNA vaccination. While the ZIKV prM-E construct alone was sufficient for generating VLPs, efficient VLP production from the C-prM-E construct could be achieved in the presence of the WNV NS2B-3 protease, which cleaves C from prM, allowing virus release. Immunization studies in mice showed that VLPs generated higher neutralizing antibody titers than those with the DNA vaccines, with C-prM-E VLPs giving slightly higher titers than those with prM-E VLPs. The superiority of C-prM-E VLPs suggests that inclusion of capsid may have benefits for ZIKV and other flaviviral VLP vaccines. To facilitate the VLP platform, we generated a stable cell line expressing high levels of ZIKV prM-E proteins that constitutively produce VLPs as well as a cell line expressing ZIKV C-prM-E proteins for RVP production. While several vaccine platforms have been proposed for ZIKV, this study describes a safe, effective, and economical VLP-based vaccine against ZIKV.IMPORTANCE To address the growing Zika virus epidemic, we undertook this study with two objectives: first, to develop a safe, effective, and economical vaccine for ZIKV, and second, to develop a rapid and versatile assay to detect the anti-ZIKV immune response. We generated a cell line stably expressing ZIKV prM-E that produces large amounts of VLPs in the supernatant and a ZIKV C-prM-E cell line that produces reporter virus particles upon transfection with a GFP replicon plasmid. The prM-E VLPs induced a strong neutralizing antibody response in mice that was better when the capsid was included. VLP-based vaccines showed significantly better neutralizing antibody responses than those with their DNA counterparts. The RVP-based microneutralization assay worked similarly to the PRNT assay, with a rapid GFP readout in a 96-well format. Our VLP-based platform provides a source for a ZIKV vaccine and diagnosis that can rapidly be adapted to current outbreaks.
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31
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Brand C, Bisaillon M, Geiss BJ. Organization of the Flavivirus RNA replicase complex. WILEY INTERDISCIPLINARY REVIEWS-RNA 2017; 8. [PMID: 28815931 DOI: 10.1002/wrna.1437] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 07/09/2017] [Accepted: 07/13/2017] [Indexed: 12/20/2022]
Abstract
Flaviviruses, such as dengue, Japanese encephalitis, West Nile, yellow fever, and Zika viruses, are serious human pathogens that cause significant morbidity and mortality globally each year. Flaviviruses are single-stranded, positive-sense RNA viruses, and encode two multidomain proteins, NS3 and NS5, that possess all enzymatic activities required for genome replication and capping. NS3 and NS5 interact within virus-induced replication compartments to form the RNA genome replicase complex. Although the individual enzymatic activities of both proteins have been extensively studied and are well characterized, there are still gaps in our understanding of how they interact to efficiently coordinate their respective activities during positive-strand RNA synthesis and capping. Here, we discuss what is known about the structures and functions of the NS3 and NS5 proteins and propose a preliminary NS3:NS5:RNA interaction model based on a large body of literature about how the viral enzymes function, physical restraints between NS3 and NS5, as well as critical steps in the replication process. WIREs RNA 2017, 8:e1437. doi: 10.1002/wrna.1437 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Carolin Brand
- Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Martin Bisaillon
- Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Brian J Geiss
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, USA.,School of Biomedical Engineering, Colorado State University, Fort Collins, CO, USA
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32
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Yun SI, Lee YM. Zika virus: An emerging flavivirus. J Microbiol 2017; 55:204-219. [PMID: 28243937 DOI: 10.1007/s12275-017-7063-6] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 02/15/2017] [Indexed: 01/18/2023]
Abstract
Zika virus (ZIKV) is a previously little-known flavivirus closely related to Japanese encephalitis, West Nile, dengue, and yellow fever viruses, all of which are primarily transmitted by blood-sucking mosquitoes. Since its discovery in Uganda in 1947, ZIKV has continued to expand its geographic range, from equatorial Africa and Asia to the Pacific Islands, then further afield to South and Central America and the Caribbean. Currently, ZIKV is actively circulating not only in much of Latin America and its neighbors but also in parts of the Pacific Islands and Southeast Asia. Although ZIKV infection generally causes only mild symptoms in some infected individuals, it is associated with a range of neuroimmunological disorders, including Guillain-Barré syndrome, meningoencephalitis, and myelitis. Recently, maternal ZIKV infection during pregnancy has been linked to neonatal malformations, resulting in various degrees of congenital abnormalities, microcephaly, and even abortion. Despite its emergence as an important public health problem, however, little is known about ZIKV biology, and neither vaccine nor drug is available to control ZIKV infection. This article provides a brief introduction to ZIKV with a major emphasis on its molecular virology, in order to help facilitate the development of diagnostics, therapeutics, and vaccines.
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Affiliation(s)
- Sang-Im Yun
- Department of Animal, Dairy, and Veterinary Sciences, Utah State University, Logan, UT, 84322-4815, USA
| | - Young-Min Lee
- Department of Animal, Dairy, and Veterinary Sciences, Utah State University, Logan, UT, 84322-4815, USA. .,Utah Science Technology and Research, College of Agriculture and Applied Sciences, Utah State University, Logan, UT, 84322-4815, USA.
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33
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Zhu Z, Chan JFW, Tee KM, Choi GKY, Lau SKP, Woo PCY, Tse H, Yuen KY. Comparative genomic analysis of pre-epidemic and epidemic Zika virus strains for virological factors potentially associated with the rapidly expanding epidemic. Emerg Microbes Infect 2016; 5:e22. [PMID: 26980239 PMCID: PMC4820678 DOI: 10.1038/emi.2016.48] [Citation(s) in RCA: 142] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 03/03/2016] [Indexed: 12/21/2022]
Abstract
Less than 20 sporadic cases of human Zika virus (ZIKV) infection were reported in Africa and Asia before 2007, but large outbreaks involving up to 73% of the populations on the Pacific islands have started since 2007, and spread to the Americas in 2014. Moreover, the clinical manifestation of ZIKV infection has apparently changed, as evident by increasing reports of neurological complications, such as Guillain-Barré syndrome in adults and congenital anomalies in neonates. We comprehensively compared the genome sequences of pre-epidemic and epidemic ZIKV strains with complete genome or complete polyprotein sequences available in GenBank. Besides the reported phylogenetic clustering of the epidemic strains with the Asian lineage, we found that the topology of phylogenetic tree of all coding regions is the same except that of the non-structural 2B (NS2B) coding region. This finding was confirmed by bootscan analysis and multiple sequence alignment, which suggested the presence of a fragment of genetic recombination at NS2B with that of Spondweni virus. Moreover, the representative epidemic strain possesses one large bulge of nine bases instead of an external loop on the first stem-loop structure at the 3'-untranslated region just distal to the stop codon of the NS5 in the 1947 pre-epidemic prototype strain. Fifteen amino acid substitutions are found in the epidemic strains when compared with the pre-epidemic strains. As mutations in other flaviviruses can be associated with changes in virulence, replication efficiency, antigenic epitopes and host tropism, further studies would be important to ascertain the biological significance of these genomic changes.
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Affiliation(s)
- Zheng Zhu
- Department of Microbiology, The University of Hong Kong, Hong Kong, China
| | - Jasper Fuk-Woo Chan
- Department of Microbiology, The University of Hong Kong, Hong Kong, China
- State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Hong Kong, China
- Research Centre of Infection and Immunology, The University of Hong Kong, Hong Kong, China
- Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong, China
| | - Kah-Meng Tee
- Department of Microbiology, The University of Hong Kong, Hong Kong, China
| | - Garnet Kwan-Yue Choi
- Research Centre of Infection and Immunology, The University of Hong Kong, Hong Kong, China
| | - Susanna Kar-Pui Lau
- Department of Microbiology, The University of Hong Kong, Hong Kong, China
- State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Hong Kong, China
- Research Centre of Infection and Immunology, The University of Hong Kong, Hong Kong, China
- Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong, China
| | - Patrick Chiu-Yat Woo
- Department of Microbiology, The University of Hong Kong, Hong Kong, China
- State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Hong Kong, China
- Research Centre of Infection and Immunology, The University of Hong Kong, Hong Kong, China
- Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong, China
| | - Herman Tse
- Department of Microbiology, The University of Hong Kong, Hong Kong, China
- State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Hong Kong, China
- Research Centre of Infection and Immunology, The University of Hong Kong, Hong Kong, China
- Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong, China
| | - Kwok-Yung Yuen
- Department of Microbiology, The University of Hong Kong, Hong Kong, China
- State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Hong Kong, China
- Research Centre of Infection and Immunology, The University of Hong Kong, Hong Kong, China
- Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong, China
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Yamaji H, Konishi E. Production of Japanese Encephalitis Virus-Like Particles Using Insect Cell Expression Systems. Methods Mol Biol 2016; 1404:365-375. [PMID: 27076311 DOI: 10.1007/978-1-4939-3389-1_25] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Virus-like particles (VLPs) can be produced via the expression of virus surface proteins that self-assemble into particulate structures in recombinant protein expression systems. Expression of the DNA fragment encoding the Japanese encephalitis (JE) virus prM signal peptide, the precursor (prM) of the viral membrane protein (M), and the envelope glycoprotein (E) allows the production of a secretory form of VLPs. Expression systems that use lepidopteran insect cells, such as the baculovirus-insect cell system and stably transformed insect cells, can be used for the efficient production of JE VLPs. This chapter describes the production of JE VLPs from stably transformed lepidopteran insect cells.
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Affiliation(s)
- Hideki Yamaji
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan.
| | - Eiji Konishi
- BIKEN Endowed Department of Dengue Vaccine Development, Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Road, Ratchathewi, Bangkok, 10400, Thailand.,BIKEN Endowed Department of Dengue Vaccine Development, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
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Context-Dependent Cleavage of the Capsid Protein by the West Nile Virus Protease Modulates the Efficiency of Virus Assembly. J Virol 2015; 89:8632-42. [PMID: 26063422 DOI: 10.1128/jvi.01253-15] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 06/02/2015] [Indexed: 12/31/2022] Open
Abstract
UNLABELLED The molecular mechanisms that define the specificity of flavivirus RNA encapsulation are poorly understood. Virions composed of the structural proteins of one flavivirus and the genomic RNA of a heterologous strain can be assembled and have been developed as live attenuated vaccine candidates for several flaviviruses. In this study, we discovered that not all combinations of flavivirus components are possible. While a West Nile virus (WNV) subgenomic RNA could readily be packaged by structural proteins of the DENV2 strain 16681, production of infectious virions with DENV2 strain New Guinea C (NGC) structural proteins was not possible, despite the very high amino acid identity between these viruses. Mutagenesis studies identified a single residue (position 101) of the DENV capsid (C) protein as the determinant for heterologous virus production. C101 is located at the P1' position of the NS2B/3 protease cleavage site at the carboxy terminus of the C protein. WNV NS2B/3 cleavage of the DENV structural polyprotein was possible when a threonine (Thr101 in strain 16681) but not a serine (Ser101 in strain NGC) occupied the P1' position, a finding not predicted by in vitro protease specificity studies. Critically, both serine and threonine were tolerated at the P1' position of WNV capsid. More extensive mutagenesis revealed the importance of flanking residues within the polyprotein in defining the cleavage specificity of the WNV protease. A more detailed understanding of the context dependence of viral protease specificity may aid the development of new protease inhibitors and provide insight into associated patterns of drug resistance. IMPORTANCE West Nile virus (WNV) and dengue virus (DENV) are mosquito-borne flaviviruses that cause considerable morbidity and mortality in humans. No specific antiflavivirus therapeutics are available for treatment of infection. Proteolytic processing of the flavivirus polyprotein is an essential step in the replication cycle and is an attractive target for antiviral development. The design of protease inhibitors has been informed by insights into the molecular details of the interactions of proteases and their substrates. In this article, studies of the processing of WNV and DENV capsid proteins by the WNV protease identified an unexpected contribution of the sequence surrounding critical residues within the cleavage site on protease specificity. This demonstration of context-dependent protease cleavage has implications for the design of chimeric flaviviruses, new therapeutics, and the interpretation of flavivirus protease substrate specificity studies.
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Kim JK, Kim JM, Song BH, Yun SI, Yun GN, Byun SJ, Lee YM. Profiling of viral proteins expressed from the genomic RNA of Japanese encephalitis virus using a panel of 15 region-specific polyclonal rabbit antisera: implications for viral gene expression. PLoS One 2015; 10:e0124318. [PMID: 25915765 PMCID: PMC4410938 DOI: 10.1371/journal.pone.0124318] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2015] [Accepted: 02/27/2015] [Indexed: 12/16/2022] Open
Abstract
Japanese encephalitis virus (JEV), a mosquito-borne flavivirus, is closely related to West Nile (WN), yellow fever (YF), and dengue (DEN) viruses. Its plus-strand genomic RNA carries a single open reading frame encoding a polyprotein that is cleaved into three structural (C, prM/M, and E) and at least seven nonstructural (NS1/NS1', NS2A, NS2B, NS3, NS4A, NS4B, and NS5) proteins, based on previous work with WNV, YFV, and DENV. Here, we aimed to profile experimentally all the viral proteins found in JEV-infected cells. We generated a collection of 15 JEV-specific polyclonal antisera covering all parts of the viral protein-coding regions, by immunizing rabbits with 14 bacterially expressed glutathione-S-transferase fusion proteins (for all nine viral proteins except NS2B) or with a chemically synthesized oligopeptide (for NS2B). In total lysates of JEV-infected BHK-21 cells, immunoblotting with these antisera revealed: (i) three mature structural proteins (~12-kDa C, ~8-kDa M, and ~53-kDa E), a precursor of M (~24-kDa prM) and three other M-related proteins (~10-14 kDa); (ii) the predicted ~45-kDa NS1 and its frameshift product, ~58-kDa NS1', with no evidence of the predicted ~25-kDa NS2A; (iii) the predicted but hardly detectable ~14-kDa NS2B and an unexpected but predominant ~12-kDa NS2B-related protein; (iv) the predicted ~69-kDa NS3 plus two major cleavage products (~34-kDa NS3N-term and ~35-kDa NS3C-term), together with at least nine minor proteins of ~16-52 kDa; (v) the predicted ~14-kDa NS4A; (vi) two NS4B-related proteins (~27-kDa NS4B and ~25-kDa NS4B'); and (vii) the predicted ~103-kDa NS5 plus at least three other NS5-related proteins (~15 kDa, ~27 kDa, and ~90 kDa). Combining these data with confocal microscopic imaging of the proteins' intracellular localization, our study is the first to provide a solid foundation for the study of JEV gene expression, which is crucial for elucidating the regulatory mechanisms of JEV genome replication and pathobiology.
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Affiliation(s)
- Jin-Kyoung Kim
- Department of Animal, Dairy, and Veterinary Sciences; Utah Science Technology and Research, College of Agriculture and Applied Sciences, Utah State University, Logan, Utah, United States of America
| | - Jeong-Min Kim
- Department of Microbiology, College of Medicine, Chungbuk National University, Cheongju, South Korea
| | - Byung-Hak Song
- Department of Animal, Dairy, and Veterinary Sciences; Utah Science Technology and Research, College of Agriculture and Applied Sciences, Utah State University, Logan, Utah, United States of America
| | - 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, Utah, United States of America
| | - Gil-Nam Yun
- Department of Microbiology, College of Medicine, Chungbuk National University, Cheongju, South Korea
| | - Sung-June Byun
- Animal Biotechnology Division, Korea National Institute of Animal Science, Suwon, South Korea
| | - 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, Utah, United States of America
- * E-mail:
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Roby JA, Setoh YX, Hall RA, Khromykh AA. Post-translational regulation and modifications of flavivirus structural proteins. J Gen Virol 2015; 96:1551-69. [PMID: 25711963 DOI: 10.1099/vir.0.000097] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Flaviviruses are a group of single-stranded, positive-sense RNA viruses that generally circulate between arthropod vectors and susceptible vertebrate hosts, producing significant human and veterinary disease burdens. Intensive research efforts have broadened our scientific understanding of the replication cycles of these viruses and have revealed several elegant and tightly co-ordinated post-translational modifications that regulate the activity of viral proteins. The three structural proteins in particular - capsid (C), pre-membrane (prM) and envelope (E) - are subjected to strict regulatory modifications as they progress from translation through virus particle assembly and egress. The timing of proteolytic cleavage events at the C-prM junction directly influences the degree of genomic RNA packaging into nascent virions. Proteolytic maturation of prM by host furin during Golgi transit facilitates rearrangement of the E proteins at the virion surface, exposing the fusion loop and thus increasing particle infectivity. Specific interactions between the prM and E proteins are also important for particle assembly, as prM acts as a chaperone, facilitating correct conformational folding of E. It is only once prM/E heterodimers form that these proteins can be secreted efficiently. The addition of branched glycans to the prM and E proteins during virion transit also plays a key role in modulating the rate of secretion, pH sensitivity and infectivity of flavivirus particles. The insights gained from research into post-translational regulation of structural proteins are beginning to be applied in the rational design of improved flavivirus vaccine candidates and make attractive targets for the development of novel therapeutics.
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Affiliation(s)
- Justin A Roby
- 1Australian Infectious Diseases Research Centre, The University of Queensland, Australia 2School of Chemistry and Molecular Biosciences, The University of Queensland, Australia
| | - Yin Xiang Setoh
- 1Australian Infectious Diseases Research Centre, The University of Queensland, Australia 2School of Chemistry and Molecular Biosciences, The University of Queensland, Australia
| | - Roy A Hall
- 1Australian Infectious Diseases Research Centre, The University of Queensland, Australia 2School of Chemistry and Molecular Biosciences, The University of Queensland, Australia
| | - Alexander A Khromykh
- 1Australian Infectious Diseases Research Centre, The University of Queensland, Australia 2School of Chemistry and Molecular Biosciences, The University of Queensland, Australia
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Dengue protease activity: the structural integrity and interaction of NS2B with NS3 protease and its potential as a drug target. Biosci Rep 2015; 31:399-409. [PMID: 21329491 DOI: 10.1042/bsr20100142] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Flaviviral NS3 serine proteases require the NS2B cofactor region (cNS2B) to be active. Recent crystal structures of WNV (West Nile virus) protease in complex with inhibitors revealed that cNS2B participates in the formation of the protease active site. No crystal structures of ternary complexes are currently available for DENV (dengue virus) to validate the role of cNS2B in active site formation. In the present study, a GST (glutathione transferase) fusion protein of DENV-2 cNS2B49-95 was used as a bait to pull down DENV-2 protease domain (NS3pro). The affinity of NS3pro for cNS2B was strong (equilibrium-binding constant <200 nM) and the heterodimeric complex displayed a catalytic efficiency similar to that of single-chain DENV-2 cNS2B/NS3pro. Various truncations and mutations in the cNS2B sequence showed that conformational integrity of the entire 47 amino acids is critical for protease activity. Furthermore, DENV-2 NS3 protease can be pulled down and transactivated by cNS2B cofactors from DENV-1, -3, -4 and WNV, suggesting that mechanisms for activation are conserved across the flavivirus genus. To validate NS2B as a potential target in allosteric inhibitor development, a cNS2B-specific human monoclonal antibody (3F10) was utilized. 3F10 disrupted the interaction between cNS2B and NS3 in vitro and reduced DENV viral replication in HEK (human embryonic kidney)-293 cells. This provides proof-of-concept for developing assays to find inhibitors that block the interaction between NS2B and NS3 during viral translation.
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Structural differences observed in arboviruses of the alphavirus and flavivirus genera. Adv Virol 2014; 2014:259382. [PMID: 25309597 PMCID: PMC4182009 DOI: 10.1155/2014/259382] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 07/28/2014] [Accepted: 08/18/2014] [Indexed: 12/22/2022] Open
Abstract
Arthropod borne viruses have developed a complex life cycle adapted to alternate between insect and vertebrate hosts. These arthropod-borne viruses belong mainly to the families Togaviridae, Flaviviridae, and Bunyaviridae. This group of viruses contains many pathogens that cause febrile, hemorrhagic, and encephalitic disease or arthritic symptoms which can be persistent. It has been appreciated for many years that these viruses were evolutionarily adapted to function in the highly divergent cellular environments of both insect and mammalian phyla. These viruses are hybrid in nature, containing viral-encoded RNA and proteins which are glycosylated by the host and encapsulate viral nucleocapsids in the context of a host-derived membrane. From a structural perspective, these virus particles are macromolecular machines adapted in design to assemble into a packaging and delivery system for the virus genome and, only when associated with the conditions appropriate for a productive infection, to disassemble and deliver the RNA cargo. It was initially assumed that the structures of the virus from both hosts were equivalent. New evidence that alphaviruses and flaviviruses can exist in more than one conformation postenvelopment will be discussed in this review. The data are limited but should refocus the field of structural biology on the metastable nature of these viruses.
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Maintenance of dimer conformation by the dengue virus core protein α4-α4' helix pair is critical for nucleocapsid formation and virus production. J Virol 2014; 88:7998-8015. [PMID: 24807709 DOI: 10.1128/jvi.00940-14] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The virion of dengue virus (DENV) is composed of a viral envelope covering a nucleocapsid formed by a complex of viral genomic RNA and core protein (CP). DENV CP forms a dimer via the internal α2 and α4 helices of each monomer. Pairing of α2-α2' creates a continuous hydrophobic surface, while the α4-α4' helix pair joins the homodimer via side-chain interactions of the inner-edge residues. However, the importance of dimer conformation and the α4 helix of DENV CP in relation to its function are poorly understood. Loss of association between CP and lipid droplets (LDs) due to mutation suggests that the CP hydrophobic surface was not exposed, offering a possible explanation for the absence of dimers. Further assays suggest the connection between CP folding and protein stability. Attenuation of full-length RNA-derived virus production is associated with CP mutation, since no significant defects were detected in virus translation and replication. The in vitro characterization assays further highlighted that the α4-α4' helix pair conformation is critical in preserving the overall α-helical content, thermostability, and dimer formation ability of CP, features correlated with the efficiency of nucleocapsid formation. Addition of Tween 20 improves in vitro nucleocapsid-like particle formation, suggesting the role of the LD in nucleocapsid formation in vivo. This study provides the first direct link between the α4-α4' helix pair interaction and the CP dimer conformation that is the basis of CP function, particularly in nucleocapsid formation during virion production. Importance: Structure-based mutagenesis study of the dengue virus core protein (CP) reveals that the α4-α4' helix pair is the key to maintaining its dimer conformation, which is the basis of CP function in nucleocapsid formation and virus production. Attenuation of full-length RNA-derived virus production is associated with CP mutation, since no significant defects in virus translation and replication were detected. In vitro inefficiency and size of nucleocapsid-like particle (NLP) formation offer a possible explanation for in vivo virus production inefficiency upon CP mutation. Further, the transition of NLP morphology from an incomplete state to an intact particle shown by α4-α4' helix pair mutants in the presence of a nonionic detergent suggests the regulatory role of the intracellular lipid droplet (LD) in CP-LD interaction and in promoting nucleocapsid formation. This study provides the first direct link between the α4-α4' helix pair interaction and CP dimer conformation that is the fundamental requirement of CP function, particularly in nucleocapsid formation during virion production.
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Rothan HA, Mohamed Z, Paydar M, Rahman NA, Yusof R. Inhibitory effect of doxycycline against dengue virus replication in vitro. Arch Virol 2013; 159:711-8. [PMID: 24142271 DOI: 10.1007/s00705-013-1880-7] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 09/29/2013] [Indexed: 11/25/2022]
Abstract
Doxycycline is an antibiotic derived from tetracycline that possesses antimicrobial and anti-inflammatory activities. Antiviral activity of doxycycline against dengue virus has been reported previously; however, its anti-dengue properties need further investigation. This study was conducted to determine the potential activity of doxycycline against dengue virus replication in vitro. Doxycycline inhibited the dengue virus serine protease (DENV2 NS2B-NS3pro) with an IC50 value of 52.3 ± 6.2 μM at 37 °C (normal human temperature) and 26.7 ± 5.3 μM at 40 °C (high fever temperature). The antiviral activity of doxycycline was first tested at different concentrations against DENV2 using a plaque-formation assay. The virus titter decreased significantly after applying doxycycline at levels lower than its 50 % cytotoxic concentration (CC50, 100 μM), showing concentration-dependent inhibition with a 50 % effective concentration (EC50) of approximately 50 μM. Doxycycline significantly inhibited viral entry and post-infection replication of the four dengue serotypes, with serotype-specific inhibition (high activity against DENV2 and DENV4 compared to DENV1 and DENV3). Collectively, these findings underline the need for further experimental and clinical studies on doxycycline, utilizing its anti-dengue and anti-inflammatory activities to attenuate the clinical symptoms of dengue virus infection.
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Affiliation(s)
- Hussin A Rothan
- Department of Molecular Medicine, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia,
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Substrate-based peptidomimetic inhibitors of the Murray Valley encephalitis virus NS2B/NS3 serine protease: A P1–P4 SAR study. Eur J Med Chem 2013; 68:72-80. [DOI: 10.1016/j.ejmech.2013.07.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Revised: 07/03/2013] [Accepted: 07/13/2013] [Indexed: 12/30/2022]
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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: 145] [Impact Index Per Article: 13.2] [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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Mairiang D, Zhang H, Sodja A, Murali T, Suriyaphol P, Malasit P, Limjindaporn T, Finley RL. Identification of new protein interactions between dengue fever virus and its hosts, human and mosquito. PLoS One 2013; 8:e53535. [PMID: 23326450 PMCID: PMC3543448 DOI: 10.1371/journal.pone.0053535] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 12/03/2012] [Indexed: 11/26/2022] Open
Abstract
The four divergent serotypes of dengue virus are the causative agents of dengue fever, dengue hemorrhagic fever and dengue shock syndrome. About two-fifths of the world's population live in areas where dengue is prevalent, and thousands of deaths are caused by the viruses every year. Dengue virus is transmitted from one person to another primarily by the yellow fever mosquito, Aedes aegypti. Recent studies have begun to define how the dengue viral proteins interact with host proteins to mediate viral replication and pathogenesis. A combined analysis of these studies, however, suggests that many virus-host protein interactions remain to be identified, especially for the mosquito host. In this study, we used high-throughput yeast two-hybrid screening to identify mosquito and human proteins that physically interact with dengue proteins. We tested each identified host protein against the proteins from all four serotypes of dengue to identify interactions that are conserved across serotypes. We further confirmed many of the interactions using co-affinity purification assays. As in other large-scale screens, we identified some previously detected interactions and many new ones, moving us closer to a complete host - dengue protein interactome. To help summarize and prioritize the data for further study, we combined our interactions with other published data and identified a subset of the host-dengue interactions that are now supported by multiple forms of evidence. These data should be useful for understanding the interplay between dengue and its hosts and may provide candidates for drug targets and vector control strategies.
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Affiliation(s)
- Dumrong Mairiang
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, Michigan, United States of America
| | - Huamei Zhang
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, Michigan, United States of America
| | - Ann Sodja
- Department of Biology, Wayne State University, Detroit, Michigan, United States of America
| | - Thilakam Murali
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, Michigan, United States of America
| | - Prapat Suriyaphol
- Bioinformatics and Data Management for Research Unit, Faculty of Medicine Siriraj Hospital, and Center for Emerging and Neglected Infectious Diseases, Mahidol University, Bangkok, Thailand
| | - Prida Malasit
- Dengue Hemorrhagic Fever Research Unit, Office for Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
- Medical Biotechnology Research Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Bangkok, Thailand
| | - Thawornchai Limjindaporn
- Department of Anatomy, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Russell L. Finley
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, Michigan, United States of America
- Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, Detroit, Michigan, United States of America
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Yamaji H, Segawa M, Nakamura M, Katsuda T, Kuwahara M, Konishi E. Production of Japanese encephalitis virus-like particles using the baculovirus–insect cell system. J Biosci Bioeng 2012; 114:657-62. [DOI: 10.1016/j.jbiosc.2012.06.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Revised: 06/05/2012] [Accepted: 06/22/2012] [Indexed: 11/29/2022]
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Rothan HA, Han HC, Ramasamy TS, Othman S, Rahman NA, Yusof R. Inhibition of dengue NS2B-NS3 protease and viral replication in Vero cells by recombinant retrocyclin-1. BMC Infect Dis 2012; 12:314. [PMID: 23171075 PMCID: PMC3575220 DOI: 10.1186/1471-2334-12-314] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2012] [Accepted: 11/19/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Global resurgence of dengue virus infections in many of the tropical and subtropical countries is a major concern. Therefore, there is an urgent need for the development of successful drugs that are both economical and offer a long-lasting protection. The viral NS2B-NS3 serine protease (NS2B-NS3pro) is a promising target for the development of drug-like inhibitors, which are not available at the moment. In this study, we report retrocyclin-1 (RC-1) production in E. coli as a recombinant peptide to test against dengue NS2B-NS3pro. METHODS Dengue NS2B-NS3pro was produced as a recombinant single chain protein in E. coli and purified by Ni+ affinity chromatography. The RC-1 peptide was produced in E. coli and the tri-disulphide bonds were reformed in a diluted alkaline environment. Protease assay was performed using a fluorogenic peptide substrate and measured by fluorescence spectrometry. Real-time PCR was used for quantification of dengue serotype 2 (DENV-2) viral RNA produced in Vero cells. RESULTS The RC-1 peptide inhibited the activity of recombinant NS2B-NS3pro with different values at 50% inhibitory concentration (IC50) which are temperature dependent (28°C, 46.1 ± 1.7 μM; 37°C, 21.4 ± 1.6 μM; 40°C, 14.1 ± 1.2 μM). The presence of RC-1 significantly reduced viral replication in Vero cells infected with DENV-2 at simultaneous treatment after 48 hrs (70%) and 75 hrs (85%). Furthermore, moderate reduction in viral replication was observed at pre-treatment mode after 48 hrs (40%) and 72 hrs (38%) and post-treatment at 48 hrs (30%) and 72 hrs (45%). CONCLUSION Recombinant RC-1 inhibits DENV-2 replication in Vero cells by interfering with the activity of its serine protease. Thus, we propose that recombinant RC-1 is a potent, cost-effective dengue virus inhibitor. Therefore, it is suitable to consider RC-1 as a new candidate for drug development against dengue infection.
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Affiliation(s)
- Hussin A Rothan
- Department of Molecular Medicine, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia.
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Ivanyi-Nagy R, Darlix JL. Reprint of: Core protein-mediated 5'-3' annealing of the West Nile virus genomic RNA in vitro. Virus Res 2012; 169:448-57. [PMID: 23022255 PMCID: PMC7172194 DOI: 10.1016/j.virusres.2012.09.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 05/08/2012] [Accepted: 05/08/2012] [Indexed: 12/21/2022]
Abstract
Genome cyclization through conserved RNA sequences located in the 5' and 3' terminal regions of flavivirus genomic RNA is essential for virus replication. Although the role of various cis-acting RNA elements in panhandle formation is well characterized, almost nothing is known about the potential contribution of protein cofactors to viral RNA cyclization. Proteins with nucleic acid chaperone activities are encoded by many viruses (e.g., retroviruses, coronaviruses) to facilitate RNA structural rearrangements and RNA-RNA interactions during the viral replicative cycle. Since the core protein of flaviviruses is also endowed with potent RNA chaperone activities, we decided to examine the effect of West Nile virus (WNV) core on 5'-3' genomic RNA annealing in vitro. Core protein binding resulted in a dramatic, dose-dependent increase in 5'-3' complex formation. Mutations introduced in either the UAR (upstream AUG region) or CS (conserved sequence) elements of the viral RNA diminished core protein-dependent annealing, while compensatory mutations restored the 5'-3' RNA interaction. The activity responsible for stimulating RNA annealing was mapped to the C-terminal RNA-binding region of WNV core protein. These results indicate that core protein - besides its function in viral particle formation - might be involved in the regulation of flavivirus genomic RNA cyclization, and thus virus replication.
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Affiliation(s)
- Roland Ivanyi-Nagy
- LaboRetro, INSERM U758, Ecole Normale Supérieure de Lyon, IFR128 Biosciences Lyon-Gerland, 46 allée d'Italie, 69364 Lyon, France
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Protegrin-1 inhibits dengue NS2B-NS3 serine protease and viral replication in MK2 cells. J Biomed Biotechnol 2012; 2012:251482. [PMID: 23093838 PMCID: PMC3470887 DOI: 10.1155/2012/251482] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 08/31/2012] [Accepted: 09/02/2012] [Indexed: 11/17/2022] Open
Abstract
Dengue diseases have an economic as well as social burden worldwide. In this study, the antiviral activity of protegrin-1 (PG-1, RGGRLCYCRRRFCVCVGR) peptide towards dengue NS2B-NS3pro and viral replication in Rhesus monkey kidney (MK2) cells was investigated. The peptide PG-1 was synthesized by solid-phase peptide synthesis, and disulphide bonds formation followed by peptide purification was confirmed by LC-MS and RPHPLC. Dengue NS2B-NS3pro was produced as a single-chain recombinant protein in E. coli. The NS2B-NS3pro assay was carried out by measuring the florescence emission of catalyzed substrate. Real-time PCR was used to evaluate the inhibition potential of PG-1 towards dengue serotype-2 (DENV-2) replication in MK2 cells. The results showed that PG-1 inhibited dengue NS2B-NS3pro at IC(50) of 11.7 μM. The graded concentrations of PG-1 at nontoxic range were able to reduce viral replication significantly (P < 0.001) at 24, 48, and 72 hrs after viral infection. However, the percentage of inhibition was significantly (P < 0.01) higher at 24 hrs compared to 48 and 72 hrs. These data show promising therapeutic potential of PG-1 against dengue infection, hence it warrants further analysis and improvement of the peptide features as a prospective starting point for consideration in designing attractive dengue virus inhibitors.
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49
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Ivanyi-Nagy R, Darlix JL. Core protein-mediated 5'-3' annealing of the West Nile virus genomic RNA in vitro. Virus Res 2012; 167:226-35. [PMID: 22652509 PMCID: PMC7172325 DOI: 10.1016/j.virusres.2012.05.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 05/08/2012] [Accepted: 05/08/2012] [Indexed: 01/17/2023]
Abstract
Genome cyclization through conserved RNA sequences located in the 5' and 3' terminal regions of flavivirus genomic RNA is essential for virus replication. Although the role of various cis-acting RNA elements in panhandle formation is well characterized, almost nothing is known about the potential contribution of protein cofactors to viral RNA cyclization. Proteins with nucleic acid chaperone activities are encoded by many viruses (e.g., retroviruses, coronaviruses) to facilitate RNA structural rearrangements and RNA-RNA interactions during the viral replicative cycle. Since the core protein of flaviviruses is also endowed with potent RNA chaperone activities, we decided to examine the effect of West Nile virus (WNV) core on 5'-3' genomic RNA annealing in vitro. Core protein binding resulted in a dramatic, dose-dependent increase in 5'-3' complex formation. Mutations introduced in either the UAR (upstream AUG region) or CS (conserved sequence) elements of the viral RNA diminished core protein-dependent annealing, while compensatory mutations restored the 5'-3' RNA interaction. The activity responsible for stimulating RNA annealing was mapped to the C-terminal RNA-binding region of WNV core protein. These results indicate that core protein - besides its function in viral particle formation - might be involved in the regulation of flavivirus genomic RNA cyclization, and thus virus replication.
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Key Words
- cs, conserved sequence
- dar, downstream aug region
- db, dumbbell-like structure
- denv, dengue virus
- jev, japanese encephalitis virus
- orf, open reading frame
- rdrp, rna-dependent rna polymerase
- sfrna, subgenomic flavivirus rna
- tbev, tick-borne encephalitis virus
- uar, upstream aug region
- utr, untranslated region
- wnv, west nile virus
- yfv, yellow fever virus
- west nile virus
- core protein
- flaviviruses
- viral replication
- genome cyclization
- rna chaperoning
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Affiliation(s)
| | - Jean-Luc Darlix
- LaboRetro, INSERM U758, Ecole Normale Supérieure de Lyon, IFR128 Biosciences Lyon-Gerland, 46 allée d’Italie, 69364 Lyon, France
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Potapova UV, Feranchuk SI, Potapov VV, Kulakova NV, Kondratov IG, Leonova GN, Belikov SI. NS2B/NS3 protease: allosteric effect of mutations associated with the pathogenicity of tick-borne encephalitis virus. J Biomol Struct Dyn 2012; 30:638-51. [PMID: 22730949 DOI: 10.1080/07391102.2012.689697] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The sequences of the protease domain of the tick-borne encephalitis (TBE) virus NS3 protein have two amino acid substitutions, 16 R→K and 45 S→F, in the highly pathogenic and poorly pathogenic strains of the virus, respectively. Two models of the NS2B-NS3 protease complex for the highly pathogenic and poorly pathogenic strains of the virus were constructed by homology modeling using the crystal structure of West Nile virus NS2B-NS3 protease as a template; 20 ns molecular dynamic simulations were performed for both models, the trajectories of the dynamic simulations were compared, and the averaged distance between the two models was calculated for each residue. Conformational differences between two models were revealed in the identified pocket. The different conformations of the pocket resulted in different orientations of the NS2B segment located near the catalytic triad. In the model of the highly pathogenic TBE virus the identified pocket had a more open conformation compared to the poorly pathogenic model. We propose that conformational changes in the active protease center, caused by two amino acid substitutions, can influence enzyme functioning and the virulence of the virus.
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Affiliation(s)
- Ulyana V Potapova
- Limnological Institute, Siberian Branch of the Russian Academy of Sciences, 3, Ulan-Batorskaya St., Irkutsk, 664033, Russian Federation.
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