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Huang S, Shi PD, Fan XX, Yang Y, Qin CF, Zhao H, Shi L, Ci Y. The glycosylation deficiency of flavivirus NS1 attenuates virus replication through interfering with the formation of viral replication compartments. J Biomed Sci 2024; 31:60. [PMID: 38849802 PMCID: PMC11157723 DOI: 10.1186/s12929-024-01048-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 05/28/2024] [Indexed: 06/09/2024] Open
Abstract
BACKGROUND Flavivirus is a challenge all over the world. The replication of flavivirus takes place within membranous replication compartments (RCs) derived from endoplasmic reticulum (ER). Flavivirus NS1 proteins have been proven essential for the formation of viral RCs by remodeling the ER. The glycosylation of flavivirus NS1 proteins is important for viral replication, yet the underlying mechanism remains unclear. METHODS HeLa cells were used to visualize the ER remodeling effects induced by NS1 expression. ZIKV replicon luciferase assay was performed with BHK-21 cells. rZIKV was generated from BHK-21 cells and the plaque assay was done with Vero Cells. Liposome co-floating assay was performed with purified NS1 proteins from 293T cells. RESULTS We found that the glycosylation of flavivirus NS1 contributes to its ER remodeling activity. Glycosylation deficiency of NS1, either through N-glycosylation sites mutations or tunicamycin treatment, compromises its ER remodeling activity and interferes with viral RCs formation. Disruption of NS1 glycosylation results in abnormal aggregation of NS1, rather than reducing its membrane-binding activity. Consequently, deficiency in NS1 glycosylation impairs virus replication. CONCLUSIONS In summary, our results highlight the significance of NS1 glycosylation in flavivirus replication and elucidate the underlying mechanism. This provides a new strategy for combating flavivirus infections.
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Affiliation(s)
- Shuhan Huang
- State Key Laboratory of Common Mechanism Research for Major Diseases, 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
| | - Pan-Deng Shi
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing, China
| | - Xiao-Xuan Fan
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing, China
| | - Yang Yang
- State Key Laboratory of Common Mechanism Research for Major Diseases, 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
| | - Cheng-Feng Qin
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing, China
| | - Hui Zhao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing, China.
| | - Lei Shi
- State Key Laboratory of Common Mechanism Research for Major Diseases, 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.
| | - Yali Ci
- State Key Laboratory of Common Mechanism Research for Major Diseases, 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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Fang E, Li M, Liu X, Hu K, Liu L, Zhang Z, Li X, Peng Q, Li Y. NS1 Protein N-Linked Glycosylation Site Affects the Virulence and Pathogenesis of Dengue Virus. Vaccines (Basel) 2023; 11:vaccines11050959. [PMID: 37243063 DOI: 10.3390/vaccines11050959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 05/02/2023] [Accepted: 05/04/2023] [Indexed: 05/28/2023] Open
Abstract
Live attenuated vaccine is one of the most effective vaccines against flavivirus. Recently, site-directed mutation of the flavivirus genome using reverse genetics techniques has been used for the rapid development of attenuated vaccines. However, this technique relies on basic research of critical virulence loci of the virus. To screen the attenuated sites in dengue virus, a total of eleven dengue virus type four mutant strains with deletion of N-glycosylation sites in the NS1 protein were designed and constructed. Ten of them (except for the N207-del mutant strain) were successfully rescued. Out of the ten strains, one mutant strain (N130del+207-209QQA) was found to have significantly reduced virulence through neurovirulence assay in suckling mice, but was genetically unstable. Further purification using the plaque purification assay yielded a genetically stable attenuated strain #11-puri9 with mutations of K129T, N130K, N207Q, and T209A in the NS1 protein and E99D in the NS2A protein. Identifying the virulence loci by constructing revertant mutant and chimeric viruses revealed that five amino acid adaptive mutations in the dengue virus type four non-structural proteins NS1 and NS2A dramatically affected its neurovirulence and could be used in constructing attenuated dengue chimeric viruses. Our study is the first to obtain an attenuated dengue virus strain through the deletion of amino acid residues at the N-glycosylation site, providing a theoretical basis for understanding the pathogenesis of the dengue virus and developing its live attenuated vaccines.
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Affiliation(s)
- Enyue Fang
- Institute of Health Inspection and Quarantine, Chinese Academy of Inspection and Quarantine, Beijing 100176, China
- Department of Arbovirus Vaccine, National Institutes for Food and Drug Control, Beijing 102629, China
| | - Miao Li
- Department of Arbovirus Vaccine, National Institutes for Food and Drug Control, Beijing 102629, China
- Vaccines R&D Department, Changchun Institute of Biological Products Co., Ltd., Changchun 130000, China
| | - Xiaohui Liu
- Department of Arbovirus Vaccine, National Institutes for Food and Drug Control, Beijing 102629, China
- Vaccines R&D Department, Changchun Institute of Biological Products Co., Ltd., Changchun 130000, China
| | - Kongxin Hu
- Institute of Health Inspection and Quarantine, Chinese Academy of Inspection and Quarantine, Beijing 100176, China
| | - Lijuan Liu
- Institute of Health Inspection and Quarantine, Chinese Academy of Inspection and Quarantine, Beijing 100176, China
| | - Zelun Zhang
- Department of Arbovirus Vaccine, National Institutes for Food and Drug Control, Beijing 102629, China
| | - Xingxing Li
- Department of Arbovirus Vaccine, National Institutes for Food and Drug Control, Beijing 102629, China
| | - Qinhua Peng
- Department of Arbovirus Vaccine, National Institutes for Food and Drug Control, Beijing 102629, China
| | - Yuhua Li
- Department of Arbovirus Vaccine, National Institutes for Food and Drug Control, Beijing 102629, China
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Feng T, Zhang J, Chen Z, Pan W, Chen Z, Yan Y, Dai J. Glycosylation of viral proteins: Implication in virus-host interaction and virulence. Virulence 2022; 13:670-683. [PMID: 35436420 PMCID: PMC9037552 DOI: 10.1080/21505594.2022.2060464] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Glycans are among the most important cell molecular components. However, given their structural diversity, their functions have not been fully explored. Glycosylation is a vital post-translational modification for various proteins. Many bacteria and viruses rely on N-linked and O-linked glycosylation to perform critical biological functions. The diverse functions of glycosylation on viral proteins during viral infections, including Dengue, Zika, influenza, and human immunodeficiency viruses as well as coronaviruses have been reported. N-linked glycosylation is the most common form of protein modification, and it modulates folding, transportation and receptor binding. Compared to N-linked glycosylation, the functions of O-linked viral protein glycosylation have not been comprehensively evaluated. In this review, we summarize findings on viral protein glycosylation, with particular attention to studies on N-linked glycosylation in viral life cycles. This review informs the development of virus-specific vaccines or inhibitors.
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Affiliation(s)
- Tingting Feng
- Jiangsu Key Laboratory of Infection and Immunity, Institute of Biology and Medical Sciences, Soochow University, Suzhou, China
| | - Jinyu Zhang
- Jiangsu Key Laboratory of Infection and Immunity, Institute of Biology and Medical Sciences, Soochow University, Suzhou, China
| | - Zhiqian Chen
- Jiangsu Key Laboratory of Infection and Immunity, Institute of Biology and Medical Sciences, Soochow University, Suzhou, China
| | - Wen Pan
- Jiangsu Key Laboratory of Infection and Immunity, Institute of Biology and Medical Sciences, Soochow University, Suzhou, China
| | - Zhengrong Chen
- Department of Respiratory Medicine, Children's Hospital of Soochow University, Soochow University, Suzhou, China
| | - Yongdong Yan
- Department of Respiratory Medicine, Children's Hospital of Soochow University, Soochow University, Suzhou, China
| | - Jianfeng Dai
- Jiangsu Key Laboratory of Infection and Immunity, Institute of Biology and Medical Sciences, Soochow University, Suzhou, China
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4
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Carpio KL, Barrett ADT. Flavivirus NS1 and Its Potential in Vaccine Development. Vaccines (Basel) 2021; 9:622. [PMID: 34207516 PMCID: PMC8229460 DOI: 10.3390/vaccines9060622] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 06/03/2021] [Accepted: 06/04/2021] [Indexed: 12/19/2022] Open
Abstract
The Flavivirus genus contains many important human pathogens, including dengue, Japanese encephalitis (JE), tick-borne encephalitis (TBE), West Nile (WN), yellow fever (YF) and Zika (ZIK) viruses. While there are effective vaccines for a few flavivirus diseases (JE, TBE and YF), the majority do not have vaccines, including WN and ZIK. The flavivirus nonstructural 1 (NS1) protein has an unusual structure-function because it is glycosylated and forms different structures to facilitate different roles intracellularly and extracellularly, including roles in the replication complex, assisting in virus assembly, and complement antagonism. It also plays a role in protective immunity through antibody-mediated cellular cytotoxicity, and anti-NS1 antibodies elicit passive protection in animal models against a virus challenge. Historically, NS1 has been used as a diagnostic marker for the flavivirus infection due to its complement fixing properties and specificity. Its role in disease pathogenesis, and the strong humoral immune response resulting from infection, makes NS1 an excellent target for inclusion in candidate flavivirus vaccines.
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Affiliation(s)
- Kassandra L. Carpio
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA;
| | - Alan D. T. Barrett
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA
- Sealy Institute for Vaccine Sciences, University of Texas Medical Branch, Galveston, TX 77555, USA
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5
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Dey D, Poudyal S, Rehman A, Hasan SS. Structural and biochemical insights into flavivirus proteins. Virus Res 2021; 296:198343. [PMID: 33607183 DOI: 10.1016/j.virusres.2021.198343] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 02/10/2021] [Accepted: 02/11/2021] [Indexed: 01/01/2023]
Abstract
Flaviviruses are the fastest spreading arthropod-borne viruses that cause severe symptoms such as hepatitis, hemorrhagic fever, encephalitis, and congenital deformities. Nearly 40 % of the entire human population is at risk of flavivirus epidemics. Yet, effective vaccination is restricted only to a few flaviviruses such as yellow fever and Japanese encephalitis viruses, and most recently for select cases of dengue virus infections. Despite the global spread of dengue virus, and emergence of new threats such as Zika virus and a new genotype of Japanese encephalitis virus, insights into flavivirus targets for potentially broad-spectrum vaccination are limited. In this review article, we highlight biochemical and structural differences in flavivirus proteins critical for virus assembly and host interactions. A comparative sequence analysis of pH-responsive properties of viral structural proteins identifies trends in conservation of complementary acidic-basic character between interacting viral structural proteins. This is highly relevant to the understanding of pH-sensitive differences in virus assembly in organelles such as neutral ER and acidic Golgi. Surface residues in viral interfaces identified by structural approaches are shown to demonstrate partial conservation, further reinforcing virus-specificity in assembly and interactions with host proteins. A comparative analysis of epitope conservation in emerging flaviviruses identifies therapeutic antibody candidates that have potential as broad spectrum anti-virals, thus providing a path towards development of vaccines.
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Affiliation(s)
- Debajit Dey
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 N. Greene Street, Baltimore MD 21201, USA
| | - Shishir Poudyal
- Department of Biological Sciences, Purdue University, 915 W. State Street, West Lafayette IN 47907, USA
| | - Asma Rehman
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 N. Greene Street, Baltimore MD 21201, USA
| | - S Saif Hasan
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 N. Greene Street, Baltimore MD 21201, USA; University of Maryland Marlene and Stewart Greenebaum Cancer Center, University of Maryland Medical Center, 22. S. Greene St. Baltimore MD 21201, USA; Center for Biomolecular Therapeutics, University of Maryland School of Medicine, 9600 Gudelsky Drive, Rockville MD 20850, USA.
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6
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Labeau A, Simon-Loriere E, Hafirassou ML, Bonnet-Madin L, Tessier S, Zamborlini A, Dupré T, Seta N, Schwartz O, Chaix ML, Delaugerre C, Amara A, Meertens L. A Genome-Wide CRISPR-Cas9 Screen Identifies the Dolichol-Phosphate Mannose Synthase Complex as a Host Dependency Factor for Dengue Virus Infection. J Virol 2020; 94:e01751-19. [PMID: 31915280 PMCID: PMC7081898 DOI: 10.1128/jvi.01751-19] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 12/20/2019] [Indexed: 12/24/2022] Open
Abstract
Dengue virus (DENV) is a mosquito-borne flavivirus responsible for dengue disease, a major human health concern for which no specific therapies are available. Like other viruses, DENV relies heavily on the host cellular machinery for productive infection. In this study, we performed a genome-wide CRISPR-Cas9 screen using haploid HAP1 cells to identify host genes important for DENV infection. We identified DPM1 and -3, two subunits of the endoplasmic reticulum (ER) resident dolichol-phosphate mannose synthase (DPMS) complex, as host dependency factors for DENV and other related flaviviruses, such as Zika virus (ZIKV). The DPMS complex catalyzes the synthesis of dolichol-phosphate mannose (DPM), which serves as mannosyl donor in pathways leading to N-glycosylation, glycosylphosphatidylinositol (GPI) anchor biosynthesis, and C- or O-mannosylation of proteins in the ER lumen. Mutation in the DXD motif of DPM1, which is essential for its catalytic activity, abolished DPMS-mediated DENV infection. Similarly, genetic ablation of ALG3, a mannosyltransferase that transfers mannose to lipid-linked oligosaccharide (LLO), rendered cells poorly susceptible to DENV. We also established that in cells deficient for DPMS activity, viral RNA amplification is hampered and truncated oligosaccharides are transferred to the viral prM and E glycoproteins, affecting their proper folding. Overall, our study provides new insights into the host-dependent mechanisms of DENV infection and supports current therapeutic approaches using glycosylation inhibitors to treat DENV infection.IMPORTANCE Dengue disease, which is caused by dengue virus (DENV), has emerged as the most important mosquito-borne viral disease in humans and is a major global health concern. DENV encodes only few proteins and relies on the host cell machinery to accomplish its life cycle. The identification of the host factors important for DENV infection is needed to propose new targets for antiviral intervention. Using a genome-wide CRISPR-Cas9 screen, we identified DPM1 and -3, two subunits of the DPMS complex, as important host factors for the replication of DENV as well as other related viruses such as Zika virus. We established that DPMS complex plays dual roles during viral infection, both regulating viral RNA replication and promoting viral structural glycoprotein folding/stability. These results provide insights into the host molecules exploited by DENV and other flaviviruses to facilitate their life cycle.
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Affiliation(s)
- Athena Labeau
- INSERM U944, CNRS UMR 7212, Genomes & Cell Biology of Disease Unit, Institut de Recherche Saint-Louis, Université de Paris, Hôpital Saint-Louis, Paris, France
| | | | - Mohamed-Lamine Hafirassou
- INSERM U944, CNRS UMR 7212, Genomes & Cell Biology of Disease Unit, Institut de Recherche Saint-Louis, Université de Paris, Hôpital Saint-Louis, Paris, France
| | - Lucie Bonnet-Madin
- INSERM U944, CNRS UMR 7212, Genomes & Cell Biology of Disease Unit, Institut de Recherche Saint-Louis, Université de Paris, Hôpital Saint-Louis, Paris, France
| | - Sarah Tessier
- INSERM U944, CNRS UMR 7212, Genomes & Cell Biology of Disease Unit, Institut de Recherche Saint-Louis, Université de Paris, Hôpital Saint-Louis, Paris, France
| | - Alessia Zamborlini
- INSERM U944, CNRS UMR 7212, Genomes & Cell Biology of Disease Unit, Institut de Recherche Saint-Louis, Université de Paris, Hôpital Saint-Louis, Paris, France
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Thierry Dupré
- Laboratoire de Biochimie, Hôpital Bichat-Claude Bernard, Paris, France
| | - Nathalie Seta
- Laboratoire de Biochimie, Hôpital Bichat-Claude Bernard, Paris, France
| | - Olivier Schwartz
- Institut Pasteur, Virus and Immunity Unit, CNRS-UMR3569, Paris, France
| | - Marie-Laure Chaix
- INSERM U944, CNRS UMR 7212, Genomes & Cell Biology of Disease Unit, Institut de Recherche Saint-Louis, Université de Paris, Hôpital Saint-Louis, Paris, France
- Laboratoire de Virologie et Département des Maladies Infectieuses, Hôpital Saint-Louis, APHP, Paris, France
| | - Constance Delaugerre
- INSERM U944, CNRS UMR 7212, Genomes & Cell Biology of Disease Unit, Institut de Recherche Saint-Louis, Université de Paris, Hôpital Saint-Louis, Paris, France
- Laboratoire de Virologie et Département des Maladies Infectieuses, Hôpital Saint-Louis, APHP, Paris, France
| | - Ali Amara
- INSERM U944, CNRS UMR 7212, Genomes & Cell Biology of Disease Unit, Institut de Recherche Saint-Louis, Université de Paris, Hôpital Saint-Louis, Paris, France
| | - Laurent Meertens
- INSERM U944, CNRS UMR 7212, Genomes & Cell Biology of Disease Unit, Institut de Recherche Saint-Louis, Université de Paris, Hôpital Saint-Louis, Paris, France
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7
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Abdullah AA, Lee YK, Chin SP, Lim SK, Lee VS, Othman R, Othman S, Rahman NA, Yusof R, Heh CH. Discovery of Dengue Virus Inhibitors. Curr Med Chem 2020; 27:4945-5036. [PMID: 30514185 DOI: 10.2174/0929867326666181204155336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 11/11/2018] [Accepted: 11/22/2018] [Indexed: 11/22/2022]
Abstract
To date, there is still no approved anti-dengue agent to treat dengue infection in the market. Although the only licensed dengue vaccine, Dengvaxia is available, its protective efficacy against serotypes 1 and 2 of dengue virus was reported to be lower than serotypes 3 and 4. Moreover, according to WHO, the risk of being hospitalized and having severe dengue increased in seronegative individuals after they received Dengvaxia vaccination. Nevertheless, various studies had been carried out in search of dengue virus inhibitors. These studies focused on the structural (C, prM, E) and non-structural proteins (NS1, NS2A, NS2B, NS3, NS4A, NS4B and NS5) of dengue virus as well as host factors as drug targets. Hence, this article provides an overall up-to-date review of the discovery of dengue virus inhibitors that are only targeting the structural and non-structural viral proteins as drug targets.
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Affiliation(s)
- Adib Afandi Abdullah
- Drug Design and Development Research Group (DDDRG), University of Malaya, Kuala Lumpur, Malaysia
| | - Yean Kee Lee
- Drug Design and Development Research Group (DDDRG), University of Malaya, Kuala Lumpur, Malaysia
| | - Sek Peng Chin
- Drug Design and Development Research Group (DDDRG), University of Malaya, Kuala Lumpur, Malaysia
| | - See Khai Lim
- Drug Design and Development Research Group (DDDRG), University of Malaya, Kuala Lumpur, Malaysia
| | - Vannajan Sanghiran Lee
- Drug Design and Development Research Group (DDDRG), University of Malaya, Kuala Lumpur, Malaysia
| | - Rozana Othman
- Drug Design and Development Research Group (DDDRG), University of Malaya, Kuala Lumpur, Malaysia
| | - Shatrah Othman
- Drug Design and Development Research Group (DDDRG), University of Malaya, Kuala Lumpur, Malaysia
| | - Noorsaadah Abdul Rahman
- Drug Design and Development Research Group (DDDRG), University of Malaya, Kuala Lumpur, Malaysia
| | - Rohana Yusof
- Drug Design and Development Research Group (DDDRG), University of Malaya, Kuala Lumpur, Malaysia
| | - Choon Han Heh
- Drug Design and Development Research Group (DDDRG), University of Malaya, Kuala Lumpur, Malaysia
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Tohma D, Tajima S, Kato F, Sato H, Kakisaka M, Hishiki T, Kataoka M, Takeyama H, Lim CK, Aida Y, Saijo M. An estrogen antagonist, cyclofenil, has anti-dengue-virus activity. Arch Virol 2018; 164:225-234. [PMID: 30357482 DOI: 10.1007/s00705-018-4079-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 10/03/2018] [Indexed: 11/27/2022]
Abstract
Dengue virus (DENV) infections are a major cause of morbidity and mortality in tropical and subtropical areas. Several compounds that act against DENV have been studied in clinical trials to date; however, there have been no compounds identified that are effective in reducing the severity of the clinical manifestations. To explore anti-DENV drugs, we examined small molecules that interact with DENV NS1 and inhibit DENV replication. Cyclofenil, which is a selective estrogen receptor modulator (SERM) and has been used clinically as an ovulation-inducing drug, showed an inhibitory effect on DENV replication in mammalian cells but not in mosquito cells. Other SERMs also inhibited DENV replication in mammalian cells, but cyclofenil showed the weakest cytotoxicity among these SERMs. Cyclofenil also inhibited the replication of Zika virus. A time-of-addition assay suggested that cyclofenil may interfere with two stages of the DENV life cycle: the translation-RNA synthesis and assembly-maturation stages. However, the level of intracellular infectious particles decreased more drastically after treatment with cyclofenil than the viral RNA level did, indicating that the assembly-maturation stage might be the main target of cyclofenil. In electron microscopy analysis, many aggregated particles were detected in DENV-infected cells in the presence of cyclofenil, supporting the possibility that cyclofenil impedes the process of assembly and maturation of DENV.
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Affiliation(s)
- Daiki Tohma
- Department of Virology I, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku, Tokyo, 162-8640, Japan
- Department of Life Science and Medical Bioscience, School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsucho, Shinjuku, Tokyo, 162-8480, Japan
| | - Shigeru Tajima
- Department of Virology I, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku, Tokyo, 162-8640, Japan.
| | - Fumihiro Kato
- Department of Virology I, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku, Tokyo, 162-8640, Japan
| | - Hirotaka Sato
- Nano Medical Engineering Laboratory, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
- Virus Infectious Diseases Unit, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Michinori Kakisaka
- Virus Infectious Diseases Unit, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Takayuki Hishiki
- Department of Microbiology, Kanagawa Prefectural Institute of Public Health, 1-3-1 Shimomachiya, Chigasaki, Kanagawa, 253-0087, Japan
| | - Michiyo Kataoka
- Department of Pathology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku, Tokyo, 162-8640, Japan
| | - Haruko Takeyama
- Department of Life Science and Medical Bioscience, School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsucho, Shinjuku, Tokyo, 162-8480, Japan
| | - Chang-Kweng Lim
- Department of Virology I, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku, Tokyo, 162-8640, Japan
| | - Yoko Aida
- Nano Medical Engineering Laboratory, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
- Virus Infectious Diseases Unit, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Masayuki Saijo
- Department of Virology I, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku, Tokyo, 162-8640, Japan
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Qadir A, Riaz M, Saeed M, Shahzad-Ul-Hussan S. Potential targets for therapeutic intervention and structure based vaccine design against Zika virus. Eur J Med Chem 2018; 156:444-460. [PMID: 30015077 DOI: 10.1016/j.ejmech.2018.07.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 06/28/2018] [Accepted: 07/06/2018] [Indexed: 01/01/2023]
Abstract
Continuously increasing number of reports of Zika virus (ZIKV) infections and associated severe clinical manifestations, including autoimmune abnormalities and neurological disorders such as neonatal microcephaly and Guillain-Barré syndrome have created alarming situation in various countries. To date, no specific antiviral therapy or vaccine is available against ZIKV. This review provides a comprehensive insight into the potential therapeutic targets and describes viral epitopes of broadly neutralizing antibodies (bNAbs) in vaccine design perspective. Interactions between ZIKV envelope glycoprotein E and cellular receptors mediate the viral fusion and entry to the target cell. Blocking these interactions by targeting cellular receptors or viral structural proteins mediating these interactions or viral surface glycans can inhibit viral entry to the cell. Similarly, different non-structural proteins of ZIKV and un-translated regions (UTRs) of its RNA play essential roles in viral replication cycle and potentiate for therapeutic interventions. Structure based vaccine design requires identity and structural description of the epitopes of bNAbs. We have described different conserved bNAb epitopes present in the ZIKV envelope as potential targets for structure based vaccine design. This review also highlights successes, unanswered questions and future perspectives in relation to therapeutic and vaccine development against ZIKV.
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Affiliation(s)
- Amina Qadir
- Department of Biology, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, Lahore, 54792, Pakistan
| | - Muhammad Riaz
- Department of Chemistry, University of Azad Jammu & Kashmir, Muzaffarabad, Pakistan
| | - Muhammad Saeed
- Department of Chemistry and Chemical Engineering, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, Lahore, 54792, Pakistan.
| | - Syed Shahzad-Ul-Hussan
- Department of Biology, Syed Babar Ali School of Science and Engineering, Lahore University of Management Sciences, Lahore, 54792, Pakistan.
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10
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Yap SSL, Nguyen-Khuong T, Rudd PM, Alonso S. Dengue Virus Glycosylation: What Do We Know? Front Microbiol 2017; 8:1415. [PMID: 28791003 PMCID: PMC5524768 DOI: 10.3389/fmicb.2017.01415] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Accepted: 07/12/2017] [Indexed: 12/04/2022] Open
Abstract
In many infectious diseases caused by either viruses or bacteria, pathogen glycoproteins play important roles during the infection cycle, ranging from entry to successful intracellular replication and host immune evasion. Dengue is no exception. Dengue virus glycoproteins, envelope protein (E) and non-structural protein 1 (NS1) are two popular sub-unit vaccine candidates. E protein on the virion surface is the major target of neutralizing antibodies. NS1 which is secreted during DENV infection has been shown to induce a variety of host responses through its binding to several host factors. However, despite their critical role in disease and protection, the glycosylated variants of these two proteins and their biological importance have remained understudied. In this review, we seek to provide a comprehensive summary of the current knowledge on protein glycosylation in DENV, and its role in virus biogenesis, host cell receptor interaction and disease pathogenesis.
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Affiliation(s)
- Sally S L Yap
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, and Immunology program, Life Sciences Institute, National University of SingaporeSingapore, Singapore
| | - Terry Nguyen-Khuong
- Analytics Group, Bioprocessing Technology Institute, A∗STARSingapore, Singapore
| | - Pauline M Rudd
- Analytics Group, Bioprocessing Technology Institute, A∗STARSingapore, Singapore
| | - Sylvie Alonso
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, and Immunology program, Life Sciences Institute, National University of SingaporeSingapore, Singapore
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Rastogi M, Sharma N, Singh SK. Flavivirus NS1: a multifaceted enigmatic viral protein. Virol J 2016; 13:131. [PMID: 27473856 PMCID: PMC4966872 DOI: 10.1186/s12985-016-0590-7] [Citation(s) in RCA: 161] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 07/26/2016] [Indexed: 12/31/2022] Open
Abstract
Flaviviruses are emerging arthropod-borne viruses representing an immense global health problem. The prominent viruses of this group include dengue virus, yellow fever virus, Japanese encephalitis virus, West Nile virus tick borne encephalitis virus and Zika Virus. These are endemic in many parts of the world. They are responsible for the illness ranging from mild flu like symptoms to severe hemorrhagic, neurologic and cognitive manifestations leading to death. NS1 is a highly conserved non-structural protein among flaviviruses, which exist in diverse forms. The intracellular dimer form of NS1 plays role in genome replication, whereas, the secreted hexamer plays role in immune evasion. The secreted NS1 has been identified as a potential diagnostic marker for early detection of the infections caused by flaviviruses. In addition to the diagnostic marker, the importance of NS1 has been reported in the development of therapeutics. NS1 based subunit vaccines are at various stages of development. The structural details and diverse functions of NS1 have been discussed in detail in this review.
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Affiliation(s)
- Meghana Rastogi
- Institute of Medical Sciences (IMS), Laboratory of Human Molecular Virology & Immunology, Molecular Biology Unit, Faculty of Medicine, Banaras Hindu University, Varanasi, 221005, India
| | - Nikhil Sharma
- Laboratory of Neurovirology and Inflammation Biology, CSIR-Centre for Cellular and Molecular Biology (CCMB), Uppal Road, Hyderabad, 500007, India
| | - Sunit Kumar Singh
- Institute of Medical Sciences (IMS), Laboratory of Human Molecular Virology & Immunology, Molecular Biology Unit, Faculty of Medicine, Banaras Hindu University, Varanasi, 221005, India.
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The C Terminus of the Core β-Ladder Domain in Japanese Encephalitis Virus Nonstructural Protein 1 Is Flexible for Accommodation of Heterologous Epitope Fusion. J Virol 2015; 90:1178-89. [PMID: 26559836 DOI: 10.1128/jvi.02057-15] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 10/30/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED NS1 is the only nonstructural protein that enters the lumen of the endoplasmic reticulum (ER), where NS1 is glycosylated, forms a dimer, and is subsequently secreted during flavivirus replication as dimers or hexamers, which appear to be highly immunogenic to the infected host, as protective immunity can be elicited against homologous flavivirus infections. Here, by using a trans-complementation assay, we identified the C-terminal end of NS1 derived from Japanese encephalitis virus (JEV), which was more flexible than other regions in terms of housing foreign epitopes without a significant impact on virus replication. This mapped flexible region is located in the conserved tip of the core β-ladder domain of the multimeric NS1 structure and is also known to contain certain linear epitopes, readily triggering specific antibody responses from the host. Despite becoming attenuated, recombinant JEV with insertion of a neutralizing epitope derived from enterovirus 71 (EV71) into the C-terminal end of NS1 not only could be normally released from infected cells, but also induced dual protective immunity for the host to counteract lethal challenge with either JEV or EV71 in neonatal mice. These results indicated that the secreted multimeric NS1 of flaviviruses may serve as a natural protein carrier to render epitopes of interest more immunogenic in the C terminus of the core β-ladder domain. IMPORTANCE The positive-sense RNA genomes of mosquito-borne flaviviruses appear to be flexible in terms of accommodating extra insertions of short heterologous antigens into their virus genes. Here, we illustrate that the newly identified C terminus of the core β-ladder domain in NS1 could be readily inserted into entities such as EV71 epitopes, and the resulting NS1-epitope fusion proteins appeared to maintain normal virus replication, secretion ability, and multimeric formation from infected cells. Nonetheless, such an insertion attenuated the recombinant JEV in mice, despite having retained the brain replication ability observed in wild-type JEV. Mother dams immunized with recombinant JEV expressing EV71 epitope-NS1 fused proteins elicited neutralizing antibodies that protected the newborn mice against lethal EV71 challenge. Together, our results implied a potential application of JEV NS1 as a viral carrier protein to express a heterologous epitope to stimulate dual/multiple protective immunity concurrently against several pathogens.
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Mutation of Putative N-Glycosylation Sites on Dengue Virus NS4B Decreases RNA Replication. J Virol 2015; 89:6746-60. [PMID: 25878113 DOI: 10.1128/jvi.00423-15] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 04/12/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Dengue virus (DENV) nonstructural protein 4B (NS4B) is an endoplasmic reticulum (ER) membrane-associated protein, and mutagenesis studies have revealed its significance in viral genome replication. In this work, we demonstrated that NS4B is an N-glycosylated protein in virus-infected cells as well as in recombinant protein expression. NS4B is N glycosylated at residues 58 and 62 and exists in two forms, glycosylated and unglycosylated. We manipulated full-length infectious RNA clones and subgenomic replicons to generate N58Q, N62Q, and N58QN62Q mutants. Each of the single mutants had distinct effects, but the N58QN62Q mutation resulted in dramatic reduction of viral production efficiency without affecting secretion or infectivity of the virion in mammalian and mosquito C6/36 hosts. Real-time quantitative PCR (qPCR), subgenomic replicon, and trans-complementation assays indicated that the N58QN62Q mutation affected RNA replication possibly by the loss of glycans. In addition, four intragenic mutations (S59Y, S59F, T66A, and A137T) were obtained from mammalian and/or mosquito C6/36 cell culture systems. All of these second-site mutations compensated for the replication defect of the N58QN62Q mutant without creating novel glycosylation sites. In vivo protein stability analyses revealed that the N58QN62Q mutation alone or plus a compensatory mutation did not affect the stability of NS4B. Overall, our findings indicated that mutation of putative N-glycosylation sites affected the biological function of NS4B in the viral replication complex. IMPORTANCE This is the first report to identify and reveal the biological significance of dengue virus (DENV) nonstructural protein 4B (NS4B) posttranslation N-glycosylation to the virus life cycle. The study demonstrated that NS4B is N glycosylated in virus-infected cells and in recombinant protein expression. NS4B is modified by glycans at Asn-58 and Asn-62. Functional characterization implied that DENV NS4B utilizes the glycosylation machinery in both mammalian and mosquito hosts. Four intragenic mutations were found to compensate for replication and subsequent viral production deficiencies without creating novel N-glycosylation sites or modulating the stabilities of the protein, suggesting that glycans may be involved in maintaining the NS4B protein conformation. NS4B glycans may be necessary elements of the viral life cycle, but compensatory mutations can circumvent their requirement. This novel finding may have broader implications in flaviviral biology as the most likely glycan at Asn-62 of NS4B is conserved in DENV serotypes and in some related flaviviruses.
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Abstract
Dengue virus (DENV) is an emerging mosquito-borne human pathogen that affects millions of individuals each year by causing severe and potentially fatal syndromes. Despite intense research efforts, no approved vaccine or antiviral therapy is yet available. Overcoming this limitation requires detailed understanding of the intimate relationship between the virus and its host cell, providing the basis to devise optimal prophylactic and therapeutic treatment options. With the advent of novel high-throughput technologies including functional genomics, transcriptomics, proteomics, and lipidomics, new important insights into the DENV replication cycle and the interaction of this virus with its host cell have been obtained. In this chapter, we provide a comprehensive overview on the current status of the DENV research field, covering every step of the viral replication cycle with a particular focus on virus-host cell interaction. We will also review specific chemical inhibitors targeting cellular factors and processes of relevance for the DENV replication cycle and their possible exploitation for the development of next generation antivirals.
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Fan J, Liu Y, Yuan Z. Critical role of Dengue Virus NS1 protein in viral replication. Virol Sin 2014; 29:162-9. [PMID: 24903593 DOI: 10.1007/s12250-014-3459-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 05/16/2014] [Indexed: 11/27/2022] Open
Abstract
Dengue virus (DENV) nonstructural protein 1 (NS1) is a highly conserved 46-kDa protein that contains 2 glycosylation sites (Asn-130 and Asn-207) and 12 conserved cysteine (Cys) residues. Here, we performed site-directed mutagenesis to generate systematic mutants of viral strain TSV01. The results of the subsequent analysis showed that an alanine substitution at the second N-linked glycan Asn-207 in NS1 delayed viral RNA synthesis, reduced virus plaque size, and weakened the cytopathic effect. Three mutants at Cys sites (Cys-4, Cys-55, Cys-291) and a C-terminal deletion (ΔC) mutant significantly impaired RNA synthesis, and consequently abolished viral growth, whereas alanine mutations at Asn-130 and Glu-173 resulted in phenotypes that were similar to the wild-type (WT) virus. Further analysis showed that the Asn-207 mutation slightly delayed viral replication. These results suggest that the three conserved disulfide bonds and the second N-linked glycan in NS1 are required for DENV-2 replication.
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Affiliation(s)
- Jingjing Fan
- Key Laboratory of Agricultural and Environmental Microbiology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
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Morrison CR, Scholle F. Abrogation of TLR3 inhibition by discrete amino acid changes in the C-terminal half of the West Nile virus NS1 protein. Virology 2014; 456-457:96-107. [PMID: 24889229 DOI: 10.1016/j.virol.2014.03.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 03/10/2014] [Accepted: 03/16/2014] [Indexed: 01/14/2023]
Abstract
West Nile virus (WNV) is a mosquito-transmitted pathogen, which causes significant disease in humans. The innate immune system is a first-line defense against invading microorganism and many flaviviruses, including WNV, have evolved multifunctional proteins, which actively suppress its activation and antiviral actions. The WNV non-structural protein 1 (NS1) inhibits signal transduction originating from Toll-like receptor 3 (TLR3) and also critically contributes to virus genome replication. In this study we developed a novel FACS-based screen to attempt to separate these two functions. The individual amino acid changes P320S and M333V in NS1 restored TLR3 signaling in virus-infected HeLa cells. However, virus replication was also attenuated, suggesting that the two functions are not easily separated and may be contained within overlapping domains. The residues we identified are completely conserved among several mosquito- and tick-borne flaviviruses, indicating that they are of biological importance to the virus.
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Affiliation(s)
- Clayton R Morrison
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
| | - Frank Scholle
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA.
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Muller DA, Young PR. The flavivirus NS1 protein: molecular and structural biology, immunology, role in pathogenesis and application as a diagnostic biomarker. Antiviral Res 2013; 98:192-208. [PMID: 23523765 DOI: 10.1016/j.antiviral.2013.03.008] [Citation(s) in RCA: 363] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 03/02/2013] [Accepted: 03/05/2013] [Indexed: 11/25/2022]
Abstract
The flavivirus nonstructural glycoprotein NS1 is an enigmatic protein whose structure and mechanistic function have remained somewhat elusive ever since it was first reported in 1970 as a viral antigen circulating in the sera of dengue-infected patients. All flavivirus NS1 genes share a high degree of homology, encoding a 352-amino-acid polypeptide that has a molecular weight of 46-55 kDa, depending on its glycosylation status. NS1 exists in multiple oligomeric forms and is found in different cellular locations: a cell membrane-bound form in association with virus-induced intracellular vesicular compartments, on the cell surface and as a soluble secreted hexameric lipoparticle. Intracellular NS1 co-localizes with dsRNA and other components of the viral replication complex and plays an essential cofactor role in replication. Although this makes NS1 an ideal target for inhibitor design, the precise nature of its cofactor function has yet to be elucidated. A plethora of potential interacting partners have been identified, particularly for the secreted form of NS1, with many being implicated in immune evasion strategies. Secreted and cell-surface-associated NS1 are highly immunogenic and both the proteins themselves and the antibodies they elicit have been implicated in the seemingly contradictory roles of protection and pathogenesis in the infected host. Finally, NS1 is also an important biomarker for early diagnosis of disease. In this article, we provide an overview of these somewhat disparate areas of research, drawing together the wealth of data generated over more than 40 years of study of this fascinating protein.
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Affiliation(s)
- David A Muller
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland 4072, Australia
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N-linked glycosylation of dengue virus NS1 protein modulates secretion, cell-surface expression, hexamer stability, and interactions with human complement. Virology 2011; 413:253-64. [PMID: 21429549 DOI: 10.1016/j.virol.2011.02.022] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Revised: 01/24/2011] [Accepted: 02/26/2011] [Indexed: 11/20/2022]
Abstract
Dengue virus (DENV) NS1 is a versatile non-structural glycoprotein that is secreted as a hexamer, binds to the cell surface of infected and uninfected cells, and has immune evasive functions. DENV NS1 displays two conserved N-linked glycans at N130 and N207. In this study, we examined the role of these two N-linked glycans on NS1 secretion, stability, and function. Because some groups have reported reduced yields of infectious DENV when N130 and N207 are changed, we analyzed glycosylation-deficient NS1 phenotypes using a transgenic expression system. We show that the N-linked glycan at position 130 is required for stabilization of the secreted hexamer whereas the N-linked glycan at residue 207 facilitates secretion and extracellular protein stability. Moreover, NS1 mutants lacking an N-linked glycan at N130 did not interact efficiently with complement components C1s and C4. In summary, our results elucidate the contribution of N-linked glycosylation to the function of DENV NS1.
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Brown WC, DelProposto J, Rubin JR, Lamiman K, Carless J, Smith JL. New ligation-independent cloning vectors compatible with a high-throughput platform for parallel construct expression evaluation using baculovirus-infected insect cells. Protein Expr Purif 2011; 77:34-45. [PMID: 21262364 DOI: 10.1016/j.pep.2011.01.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Revised: 01/16/2011] [Accepted: 01/18/2011] [Indexed: 11/19/2022]
Abstract
Biomedical research has undergone a major shift in emphasis over the past decade from characterizing the genomes of organisms to characterizing their proteomes. The high-throughput approaches that were successfully applied to sequencing of genomes, such as miniaturization and automation, have been adapted for high-throughput cloning and protein production. High-throughput platforms allow for a multi-construct, multi-parallel approach to expression optimization and construct evaluation. We describe here a series of baculovirus transfer and expression vectors that contain ligation-independent cloning regions originally designed for use in high-throughput Escherichia coli expression evaluation. These new vectors allow for parallel cloning of the same gene construct into a variety of baculovirus or E. coli expression vectors. A high-throughput platform for construct expression evaluation in baculovirus-infected insect cells was developed to utilize these vectors. Data from baculovirus infection expression trials for multiple constructs of two target protein systems relevant to the study of human diseases are presented. The target proteins exhibit a wide variation in behavior and illustrate the benefit of investigating multiple cell types, fusion partners and secretion signals in optimization of constructs and conditions for eukaryotic protein production.
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Affiliation(s)
- William Clay Brown
- High-throughput Protein Lab, Center for Structural Biology, Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA.
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Rodenhuis-Zybert IA, Wilschut J, Smit JM. Dengue virus life cycle: viral and host factors modulating infectivity. Cell Mol Life Sci 2010; 67:2773-86. [PMID: 20372965 PMCID: PMC11115823 DOI: 10.1007/s00018-010-0357-z] [Citation(s) in RCA: 286] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2010] [Revised: 03/08/2010] [Accepted: 03/16/2010] [Indexed: 11/25/2022]
Abstract
Dengue virus (DENV 1-4) represents a major emerging arthropod-borne pathogen. All four DENV serotypes are prevalent in the (sub) tropical regions of the world and infect 50-100 million individuals annually. Whereas the majority of DENV infections proceed asymptomatically or result in self-limited dengue fever, an increasing number of patients present more severe manifestations, such as dengue hemorrhagic fever and dengue shock syndrome. In this review we will give an overview of the infectious life cycle of DENV and will discuss the viral and host factors that are important in controlling DENV infection.
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Affiliation(s)
- Izabela A. Rodenhuis-Zybert
- Molecular Virology Section, Department of Medical Microbiology, University Medical Center Groningen, University of Groningen, PO Box 30.001, 9700 RB Groningen, The Netherlands
| | - Jan Wilschut
- Molecular Virology Section, Department of Medical Microbiology, University Medical Center Groningen, University of Groningen, PO Box 30.001, 9700 RB Groningen, The Netherlands
| | - Jolanda M. Smit
- Molecular Virology Section, Department of Medical Microbiology, University Medical Center Groningen, University of Groningen, PO Box 30.001, 9700 RB Groningen, The Netherlands
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Sayce AC, Miller JL, Zitzmann N. Targeting a host process as an antiviral approach against dengue virus. Trends Microbiol 2010; 18:323-30. [PMID: 20452219 DOI: 10.1016/j.tim.2010.04.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Revised: 04/06/2010] [Accepted: 04/12/2010] [Indexed: 11/28/2022]
Abstract
The re-emergence of dengue virus as a significant human pathogen has lead to an increasing need for effective antivirals. Development of therapeutic agents with the ability to attenuate both the duration and severity of disease in patients after infection is particularly desirable in dengue endemic resource-poor settings. The reliance of dengue virus on endogenous processes during the late stages of infection prompts the development of molecules to interfere with and exploit these dependencies as potential antiviral therapies. Here we focus on the importance of N-linked glycan processing in infectious virion morphogenesis.
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Affiliation(s)
- Andrew C Sayce
- Department of Genetics and Biochemistry, Clemson University, 217 Biosystems Research Complex, 51 New Cherry Street, Clemson, SC 29634, USA
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Abstract
The innate immune response is the first line of defense against foreign pathogens. The recognition of virus-associated molecular patterns, including double- and single-stranded RNA, by pattern recognition receptors initiates a cascade of signaling reactions. These result in the transcriptional upregulation and secretion of proinflammatory cytokines that induce an antiviral state. Many viruses have evolved mechanisms to antagonize these responses in order to help them establish a productive infection. We have previously shown that West Nile virus (WNV) is able to inhibit Toll-like receptor 3 (TLR3)-mediated activation of interferon (IFN) regulatory factor 3 (IRF3) (F. Scholle and P. W. Mason, Virology 342:77-87, 2005). In the present study, the WNV nonstructural (NS) proteins were analyzed individually for their ability to antagonize signal transduction mediated by TLR3. We report that expression of WNV NS1 inhibits TLR3-induced transcriptional activation of the IFN-beta promoter and of an NF-kappaB-responsive promoter. This inhibition was due to a failure of the TLR3 ligand poly(I:C) to induce nuclear translocation of IRF3 and NF-kappaB. Furthermore, NS1 expression also inhibited TLR3-dependent production of interleukin-6 and the establishment of an antiviral state. The function of NS1 in flavivirus infection is not well understood. NS1 is required for viral RNA replication and is also secreted from mammalian cells but not from insect cells. Here, we identify a previously unrecognized role for NS1 in the modulation of signaling pathways of the innate immune response to WNV infection.
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