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Genoyer E, Wilson J, Ames JM, Stokes C, Moreno D, Etzyon N, Oberst A, Gale M. Exposure of negative-sense viral RNA in the cytoplasm initiates innate immunity to West Nile virus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.07.597966. [PMID: 38895355 PMCID: PMC11185705 DOI: 10.1101/2024.06.07.597966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
For many RNA viruses, immunity is triggered when RIG-I-like receptors (RLRs) detect viral RNA. However, only a minority of infected cells undergo innate immune activation. By examining these "first responder" cells during West Nile virus infection, we found that specific accumulation of anti- genomic negative-sense viral RNA (-vRNA) underlies innate immune activation and that RIG-I preferentially interacts with -vRNA. However, flaviviruses sequester -vRNA into membrane-bound replication compartments away from cytosolic sensors. We found that single-stranded -vRNA accumulates outside of replication compartments in "first responder" cells, rendering it accessible to RLRs. Exposure of this -vRNA occurs at late timepoints of infection, is linked to viral assembly, and depends on the expression of viral structural proteins. These findings reveal that while most infected cells replicate high levels of vRNA, release of -vRNA from replication compartments during assembly occurs at low frequency and is critical for initiation of innate immunity during flavivirus infection.
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Ma X, Xia Q, Liu K, Wu Z, Li C, Xiao C, Dong N, Hameed M, Anwar MN, Li Z, Shao D, Li B, Qiu Y, Wei J, Ma Z. Palmitoylation at Residue C221 of Japanese Encephalitis Virus NS2A Protein Contributes to Viral Replication Efficiency and Virulence. J Virol 2023; 97:e0038223. [PMID: 37289075 PMCID: PMC10308905 DOI: 10.1128/jvi.00382-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 05/13/2023] [Indexed: 06/09/2023] Open
Abstract
Palmitoylation of viral proteins is crucial for host-virus interactions. In this study, we examined the palmitoylation of Japanese encephalitis virus (JEV) nonstructural protein 2A (NS2A) and observed that NS2A was palmitoylated at the C221 residue of NS2A. Blocking NS2A palmitoylation by introducing a cysteine-to-serine mutation at C221 (NS2A/C221S) impaired JEV replication in vitro and attenuated the virulence of JEV in mice. NS2A/C221S mutation had no effect on NS2A oligomerization and membrane-associated activities, but reduced protein stability and accelerated its degradation through the ubiquitin-proteasome pathway. These observations suggest that NS2A palmitoylation at C221 played a role in its protein stability, thereby contributing to JEV replication efficiency and virulence. Interestingly, the C221 residue undergoing palmitoylation was located at the C-terminal tail (amino acids 195 to 227) and is removed from the full-length NS2A following an internal cleavage processed by viral and/or host proteases during JEV infection. IMPORTANCE An internal cleavage site is present at the C terminus of JEV NS2A. Following occurrence of the internal cleavage, the C-terminal tail (amino acids 195 to 227) is removed from the full-length NS2A. Therefore, it was interesting to discover whether the C-terminal tail contributed to JEV infection. During analysis of viral palmitoylated protein, we observed that NS2A was palmitoylated at the C221 residue located at the C-terminal tail. Blocking NS2A palmitoylation by introducing a cysteine-to-serine mutation at C221 (NS2A/C221S) impaired JEV replication in vitro and attenuated JEV virulence in mice, suggesting that NS2A palmitoylation at C221 contributed to JEV replication and virulence. Based on these findings, we could infer that the C-terminal tail might play a role in the maintenance of JEV replication efficiency and virulence despite its removal from the full-length NS2A at a certain stage of JEV infection.
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Affiliation(s)
- Xiaochun Ma
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People’s Republic of China
- College of Veterinary Medicine, Shandong Vocational Animal Science and Veterinary College, Weifang, People’s Republic of China
| | - Qiqi Xia
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People’s Republic of China
| | - Ke Liu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People’s Republic of China
| | - Zhuanchang Wu
- Key Laboratory for Experimental Teratology of Ministry of Education and Department of Immunology, School of Basic Medical Science, Shandong University, Jinan, People’s Republic of China
| | - Chenxi Li
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People’s Republic of China
| | - Changguang Xiao
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People’s Republic of China
| | - Nihua Dong
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People’s Republic of China
| | - Muddassar Hameed
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People’s Republic of China
| | - Muhammad Naveed Anwar
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People’s Republic of China
- Institute of Microbiology, University of Agriculture, Faisalabad, Pakistan
| | - Zongjie Li
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People’s Republic of China
| | - Donghua Shao
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People’s Republic of China
| | - Beibei Li
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People’s Republic of China
| | - Yafeng Qiu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People’s Republic of China
| | - Jianchao Wei
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People’s Republic of China
| | - Zhiyong Ma
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People’s Republic of China
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Nonyong P, Ekalaksananan T, Phanthanawiboon S, Overgaard HJ, Alexander N, Thaewnongiew K, Sawaswong V, Nimsamer P, Payungporn S, Phadungsombat J, Nakayama EE, Shioda T, Pientong C. Intrahost Genetic Diversity of Dengue Virus in Human Hosts and Mosquito Vectors under Natural Conditions Which Impact Replicative Fitness In Vitro. Viruses 2023; 15:982. [PMID: 37112962 PMCID: PMC10143933 DOI: 10.3390/v15040982] [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: 02/04/2023] [Revised: 04/08/2023] [Accepted: 04/16/2023] [Indexed: 04/29/2023] Open
Abstract
Dengue virus (DENV) is an arbovirus whose transmission cycle involves disparate hosts: humans and mosquitoes. The error-prone nature of viral RNA replication drives the high mutation rates, and the consequently high genetic diversity affects viral fitness over this transmission cycle. A few studies have been performed to investigate the intrahost genetic diversity between hosts, although their mosquito infections were performed artificially in the laboratory setting. Here, we performed whole-genome deep sequencing of DENV-1 (n = 11) and DENV-4 (n = 13) derived from clinical samples and field-caught mosquitoes from the houses of naturally infected patients, in order to analyze the intrahost genetic diversity of DENV between host types. Prominent differences in DENV intrahost diversity were observed in the viral population structure between DENV-1 and DENV-4, which appear to be associated with differing selection pressures. Interestingly, three single amino acid substitutions in the NS2A (K81R), NS3 (K107R), and NS5 (I563V) proteins in DENV-4 appear to be specifically acquired during infection in Ae. aegypti mosquitoes. Our in vitro study shows that the NS2A (K81R) mutant replicates similarly to the wild-type infectious clone-derived virus, while the NS3 (K107R), and NS5 (I563V) mutants have prolonged replication kinetics in the early phase in both Vero and C6/36 cells. These findings suggest that DENV is subjected to selection pressure in both mosquito and human hosts. The NS3 and NS5 genes may be specific targets of diversifying selection that play essential roles in early processing, RNA replication, and infectious particle production, and they are potentially adaptive at the population level during host switching.
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Affiliation(s)
- Patcharaporn Nonyong
- Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand; (P.N.); (T.E.); (S.P.)
| | - Tipaya Ekalaksananan
- Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand; (P.N.); (T.E.); (S.P.)
- HPV & EBV and Carcinogenesis Research Group, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Supranee Phanthanawiboon
- Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand; (P.N.); (T.E.); (S.P.)
| | - Hans J. Overgaard
- Faculty of Science and Technology, Norwegian University of Life Sciences, P.O. Box 5003, 1432 Ås, Norway;
| | - Neal Alexander
- MRC International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK;
| | - Kesorn Thaewnongiew
- Department of Disease Control, Office of Disease Prevention and Control, Region 7 Khon Kaen, Ministry of Public Health, Khon Kaen 40000, Thailand;
| | - Vorthon Sawaswong
- Program in Bioinformatics and Computational Biology, Graduate School, Chulalongkorn University, Bangkok 10330, Thailand;
- Center of Excellence in Systems Biology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand; (P.N.); (S.P.)
| | - Pattaraporn Nimsamer
- Center of Excellence in Systems Biology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand; (P.N.); (S.P.)
| | - Sunchai Payungporn
- Center of Excellence in Systems Biology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand; (P.N.); (S.P.)
- Department of Biochemistry, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand
| | - Juthamas Phadungsombat
- Mahidol-Osaka Center for Infectious Diseases (MOCID), Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand; (J.P.); (E.E.N.)
| | - Emi E. Nakayama
- Mahidol-Osaka Center for Infectious Diseases (MOCID), Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand; (J.P.); (E.E.N.)
- Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Tatsuo Shioda
- Mahidol-Osaka Center for Infectious Diseases (MOCID), Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand; (J.P.); (E.E.N.)
- Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Chamsai Pientong
- Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand; (P.N.); (T.E.); (S.P.)
- HPV & EBV and Carcinogenesis Research Group, Khon Kaen University, Khon Kaen 40002, Thailand
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Dharmapalan BT, Biswas R, Sankaran S, Venkidasamy B, Thiruvengadam M, George G, Rebezov M, Zengin G, Gallo M, Montesano D, Naviglio D, Shariati MA. Inhibitory Potential of Chromene Derivatives on Structural and Non-Structural Proteins of Dengue Virus. Viruses 2022; 14:v14122656. [PMID: 36560664 PMCID: PMC9787897 DOI: 10.3390/v14122656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 11/16/2022] [Accepted: 11/24/2022] [Indexed: 11/29/2022] Open
Abstract
Dengue fever is a mosquito-borne viral disease that has become a serious health issue across the globe. It is caused by a virus of the Flaviviridae family, and it comprises five different serotypes (DENV-1 to DENV-5). As there is no specific medicine or effective vaccine for controlling dengue fever, there is an urgent need to develop potential inhibitors against it. Traditionally, various natural products have been used to manage dengue fever and its co-morbid conditions. A detailed analysis of these plants revealed the presence of various chromene derivatives as the major phytochemicals. Inspired by these observations, authors have critically analyzed the anti-dengue virus potential of various 4H chromene derivatives. Further, in silico, in vitro, and in vivo reports of these scaffolds against the dengue virus are detailed in the present manuscript. These analogues exerted their activity by interfering with various stages of viral entry, assembly, and replications. Moreover, these analogues mainly target envelope protein, NS2B-NS3 protease, and NS5 RNA-dependent RNA polymerase, etc. Overall, chromene-containing analogues exerted a potent activity against the dengue virus and the present review will be helpful for the further exploration of these scaffolds for the development of novel antiviral drug candidates.
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Affiliation(s)
- Babitha Thekkiniyedath Dharmapalan
- Department of Pharmaceutical Chemistry, Amrita School of Pharmacy, AIMS Health Sciences Campus, Amrita Vishwa Vidyapeetham, Kochi 682041, India
| | - Raja Biswas
- Centre for Nanosciences and Molecular Medicine, Amrita Vishwa Vidyapeetham, Kochi 682041, India
| | - Sathianarayanan Sankaran
- Faculty of Pharmacy, Karpagam Academy of Higher Education, Karpagam University, Pollachi Main Road, Eachanari Post, Coimbatore 641021, India
- Correspondence: (S.S.); (G.G.); (M.G.)
| | - Baskar Venkidasamy
- Department of Oral and Maxillofacial Surgery, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai 600077, India
| | - Muthu Thiruvengadam
- Department of Applied Bioscience, College of Life and Environmental Sciences, Konkuk University, Seoul 05029, Republic of Korea
| | - Ginson George
- Department of Pharmaceutical Chemistry, Amrita School of Pharmacy, AIMS Health Sciences Campus, Amrita Vishwa Vidyapeetham, Kochi 682041, India
- Correspondence: (S.S.); (G.G.); (M.G.)
| | - Maksim Rebezov
- Department of Scientific Research, K.G. Razumovsky Moscow State University of Technologies and Management (The First Cossack University), 73 Zemlyanoy Val, 109004 Moscow, Russia
- Department of Scientific Research, Russian State Agrarian University—Moscow Timiryazev Agricultural Academy, 49 Timiryazevskaya Str., 127550 Moscow, Russia
- Faculty of Biotechnology and Food Engineering, Ural State Agricultural University, 42 Karl Liebknecht Str., 620075 Yekaterinburg, Russia
| | - Gokhan Zengin
- Department of Biology, Science Faculty, Selcuk University, Konya 42130, Turkey
| | - Monica Gallo
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Via Pansini 5, 80131 Naples, Italy
- Correspondence: (S.S.); (G.G.); (M.G.)
| | - Domenico Montesano
- Department of Pharmacy, University of Naples Federico II, Via D. Montesano 49, 80131 Naples, Italy
| | - Daniele Naviglio
- Department of Chemical Sciences, University of Naples Federico II, Via Cintia 4, 80126 Naples, Italy
| | - Mohammad Ali Shariati
- Department of Scientific Research, K.G. Razumovsky Moscow State University of Technologies and Management (The First Cossack University), 73 Zemlyanoy Val, 109004 Moscow, Russia
- Department of Scientific Research, Russian State Agrarian University—Moscow Timiryazev Agricultural Academy, 49 Timiryazevskaya Str., 127550 Moscow, Russia
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5
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Latanova A, Starodubova E, Karpov V. Flaviviridae Nonstructural Proteins: The Role in Molecular Mechanisms of Triggering Inflammation. Viruses 2022; 14:v14081808. [PMID: 36016430 PMCID: PMC9414172 DOI: 10.3390/v14081808] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 08/13/2022] [Accepted: 08/15/2022] [Indexed: 12/24/2022] Open
Abstract
Members of the Flaviviridae family are posing a significant threat to human health worldwide. Many flaviviruses are capable of inducing severe inflammation in humans. Flaviviridae nonstructural proteins, apart from their canonical roles in viral replication, have noncanonical functions strongly affecting antiviral innate immunity. Among these functions, antagonism of type I IFN is the most investigated; meanwhile, more data are accumulated on their role in the other pathways of innate response. This review systematizes the last known data on the role of Flaviviridae nonstructural proteins in molecular mechanisms of triggering inflammation, with an emphasis on their interactions with TLRs and RLRs, interference with NF-κB and cGAS-STING signaling, and activation of inflammasomes.
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Human pathogenic RNA viruses establish noncompeting lineages by occupying independent niches. Proc Natl Acad Sci U S A 2022; 119:e2121335119. [PMID: 35639694 PMCID: PMC9191635 DOI: 10.1073/pnas.2121335119] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Numerous pathogenic viruses are endemic in humans and cause a broad variety of diseases, but what is their potential for causing new pandemics? We show that most human pathogenic RNA viruses form multiple, cocirculating lineages with low turnover rates. These lineages appear to be largely noncompeting and occupy distinct epidemiological niches that are not regionally or seasonally defined, and their persistence appears to stem from limited outbreaks in small communities so that only a small fraction of the global susceptible population is infected at any time. However, due to globalization, interaction and competition between lineages might increase, potentially leading to increased diversification and pathogenicity. Thus, endemic viruses appear to merit global attention with respect to the prevention of future pandemics. Many pathogenic viruses are endemic among human populations and can cause a broad variety of diseases, some potentially leading to devastating pandemics. How virus populations maintain diversity and what selective pressures drive population turnover is not thoroughly understood. We conducted a large-scale phylodynamic analysis of 27 human pathogenic RNA viruses spanning diverse life history traits, in search of unifying trends that shape virus evolution. For most virus species, we identify multiple, cocirculating lineages with low turnover rates. These lineages appear to be largely noncompeting and likely occupy semiindependent epidemiological niches that are not regionally or seasonally defined. Typically, intralineage mutational signatures are similar to interlineage signatures. The principal exception are members of the family Picornaviridae, for which mutations in capsid protein genes are primarily lineage defining. Interlineage turnover is slower than expected under a neutral model, whereas intralineage turnover is faster than the neutral expectation, further supporting the existence of independent niches. The persistence of virus lineages appears to stem from limited outbreaks within small communities, so that only a small fraction of the global susceptible population is infected at any time. As disparate communities become increasingly connected through globalization, interaction and competition between lineages might increase as well, which could result in changing selective pressures and increased diversification and/or pathogenicity. Thus, in addition to zoonotic events, ongoing surveillance of familiar, endemic viruses appears to merit global attention with respect to the prevention or mitigation of future pandemics.
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Peñaflor-Téllez Y, Chávez-Munguía B, Lagunes-Guillén A, Salazar-Villatoro L, Gutiérrez-Escolano AL. The Feline Calicivirus Leader of the Capsid Protein Has the Functional Characteristics of a Viroporin. Viruses 2022; 14:v14030635. [PMID: 35337042 PMCID: PMC8955107 DOI: 10.3390/v14030635] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 02/21/2022] [Accepted: 02/22/2022] [Indexed: 12/27/2022] Open
Abstract
The leader of the capsid (LC) protein is exclusive to the Vesivirus genus, and it is needed for successful feline calicivirus (FCV) replication, as well as an efficient apoptosis induction through the mitochondrial pathway. In this work, we aimed to determine if the LC protein from the FCV is a viroporin. Although lacking in a transmembrane domain or an amphipathic helix, the LC protein from the FCV is toxic when expressed in bacteria and it oligomerizes through disulfide bonds, which are both key characteristics of viroporins. An electron microscopy analysis of LC-expressing E. coli cells suggest that the protein induces osmotic stress. Moreover, we found that the previously studied C40A LC mutant, that fails to induce apoptosis and that hinders the replication cycle, also oligomerizes but it has a reduced toxicity and fails to induce osmotic stress in bacteria. We propose that the LC protein is a viroporin that acts as a disulfide bond-dependent antimicrobial peptide, similar to the Ebola virus delta peptide.
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8
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In Vitro Inhibition of Zika Virus Replication with Amantadine and Rimantadine Hydrochlorides. MICROBIOLOGY RESEARCH 2021. [DOI: 10.3390/microbiolres12030052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Zika virus (ZIKV) is a mosquito-borne flavivirus in which human infection became relevant during recent outbreaks in Latin America due to its unrecognized association with fetal neurological disorders. Currently, there are no approved effective antivirals or vaccines for the treatment or prevention of ZIKV infections. Amantadine and rimantadine are approved antivirals used against susceptible influenza A virus infections that have been shown to have antiviral activity against other viruses, such as dengue virus (DENV). Here, we report the in vitro effectiveness of both amantadine and rimantadine hydrochlorides against ZIKV replication, resulting in a dose-dependent reduction in viral titers of a ZIKV clinical isolate and two different ZIKV reference strains. Additionally, we demonstrate similar in vitro antiviral activity of these drugs against DENV-1 and yellow fever virus (YFV), although at higher drug concentrations for the latter. ZIKV replication was inhibited at drug concentrations well below cytotoxic levels of both compounds, as denoted by the high selectivity indexes obtained with the tested strains. Further work is absolutely needed to determine the potential clinical use of these antivirals against ZIKV infections, but our results suggest the existence of a highly conserved mechanism across flavivirus, susceptible to be blocked by modified more specific adamantane compounds.
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Ci Y, Shi L. Compartmentalized replication organelle of flavivirus at the ER and the factors involved. Cell Mol Life Sci 2021; 78:4939-4954. [PMID: 33846827 PMCID: PMC8041242 DOI: 10.1007/s00018-021-03834-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 03/16/2021] [Accepted: 04/01/2021] [Indexed: 12/14/2022]
Abstract
Flaviviruses are positive-sense single-stranded RNA viruses that pose a considerable threat to human health. Flaviviruses replicate in compartmentalized replication organelles derived from the host endoplasmic reticulum (ER). The characteristic architecture of flavivirus replication organelles includes invaginated vesicle packets and convoluted membrane structures. Multiple factors, including both viral proteins and host factors, contribute to the biogenesis of the flavivirus replication organelle. Several viral nonstructural (NS) proteins with membrane activity induce ER rearrangement to build replication compartments, and other NS proteins constitute the replication complexes (RC) in the compartments. Host protein and lipid factors facilitate the formation of replication organelles. The lipid membrane, proteins and viral RNA together form the functional compartmentalized replication organelle, in which the flaviviruses efficiently synthesize viral RNA. Here, we reviewed recent advances in understanding the structure and biogenesis of flavivirus replication organelles, and we further discuss the function of virus NS proteins and related host factors as well as their roles in building the replication organelle.
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Affiliation(s)
- Yali Ci
- 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.
| | - 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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10
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Lien TS, Sun DS, Hung SC, Wu WS, Chang HH. Dengue Virus Envelope Protein Domain III Induces Nlrp3 Inflammasome-Dependent NETosis-Mediated Inflammation in Mice. Front Immunol 2021; 12:618577. [PMID: 33815373 PMCID: PMC8009969 DOI: 10.3389/fimmu.2021.618577] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Accepted: 02/22/2021] [Indexed: 12/18/2022] Open
Abstract
Abnormal immune responses and cytokine storm are involved in the development of severe dengue, a life-threatening disease with high mortality. Dengue virus-induced neutrophil NETosis response is associated with cytokine storm; while the role of viral factors on the elicitation of excessive inflammation mains unclear. Here we found that treatments of dengue virus envelope protein domain III (EIII), cellular binding moiety of virion, is sufficient to induce neutrophil NETosis processes in vitro and in vivo. Challenges of EIII in inflammasome Nlrp3-/- and Casp1-/- mutant mice resulted in less inflammation and NETosis responses, as compared to the wild type controls. Blockages of EIII-neutrophil interaction using cell-binding competitive inhibitor or selective Nlrp3 inflammasome inhibitors OLT1177 and Z-WHED-FMK can suppress EIII-induced NETosis response. These results collectively suggest that Nlrp3 inflammsome is a molecular target for treating dengue-elicited inflammatory pathogenesis.
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Affiliation(s)
- Te-Sheng Lien
- Department of Molecular Biology and Human Genetics, Tzu-Chi University, Hualien, Taiwan
| | - Der-Shan Sun
- Department of Molecular Biology and Human Genetics, Tzu-Chi University, Hualien, Taiwan
- Institute of Medical Sciences, Tzu-Chi University, Hualien, Taiwan
| | - Shih-Che Hung
- Institute of Medical Sciences, Tzu-Chi University, Hualien, Taiwan
| | - Wen-Sheng Wu
- Division of General Surgery, Department of Surgery, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan
- School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Hsin-Hou Chang
- Department of Molecular Biology and Human Genetics, Tzu-Chi University, Hualien, Taiwan
- Institute of Medical Sciences, Tzu-Chi University, Hualien, Taiwan
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11
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Barnard TR, Abram QH, Lin QF, Wang AB, Sagan SM. Molecular Determinants of Flavivirus Virion Assembly. Trends Biochem Sci 2021; 46:378-390. [PMID: 33423940 DOI: 10.1016/j.tibs.2020.12.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 12/07/2020] [Accepted: 12/08/2020] [Indexed: 01/07/2023]
Abstract
Virion assembly is an important step in the life cycle of all viruses. For viruses of the Flavivirus genus, a group of enveloped positive-sense RNA viruses, the assembly step represents one of the least understood processes in the viral life cycle. While assembly is primarily driven by the viral structural proteins, recent studies suggest that several nonstructural proteins also play key roles in coordinating the assembly and packaging of the viral genome. This review focuses on describing recent advances in our understanding of flavivirus virion assembly, including the intermolecular interactions between the viral structural (capsid) and nonstructural proteins (NS2A and NS2B-NS3), host factors, as well as features of the viral genomic RNA required for efficient flavivirus virion assembly.
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Affiliation(s)
- Trisha R Barnard
- Department of Microbiology & Immunology, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Quinn H Abram
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Qi Feng Lin
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Alex B Wang
- Department of Microbiology & Immunology, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Selena M Sagan
- Department of Microbiology & Immunology, McGill University, Montreal, Quebec H3G 1Y6, Canada; Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada.
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12
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[Activation of positive-strand RNA virus genome replication complexes by host oxidation machinery and viroporins]. Uirusu 2021; 71:55-62. [PMID: 35526995 DOI: 10.2222/jsv.71.55] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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13
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Transmembrane redox regulation of genome replication functions in positive-strand RNA viruses. Curr Opin Virol 2020; 47:25-31. [PMID: 33383355 DOI: 10.1016/j.coviro.2020.12.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 12/02/2020] [Accepted: 12/08/2020] [Indexed: 02/07/2023]
Abstract
Positive-strand RNA virus genome replication takes place on intracellular membranes that separate the reduced cytosol from the oxidized extracellular/luminal milieu. Ongoing studies of these membrane-bounded genome replication complexes have revealed underlying common principles in their structure, assembly and functionalization, including transmembrane features and redox dependencies. Among these, members of the alphavirus, flavivirus, and picornavirus supergroups all encode membrane-permeabilizing viroporins required for efficient RNA replication. For flaviviruses and particularly alphavirus supergroup members, these viroporins are linked to activating viral RNA capping and potentially other later-stage RNA replication functions, and to local transmembrane release of oxidizing potential to trigger these changes in cytoplasmic RNA replication complexes. Further exploration of these emerging shared principles could spur development of broad-spectrum antivirals.
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14
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Shrivastava G, Valenzuela Leon PC, Calvo E. Inflammasome Fuels Dengue Severity. Front Cell Infect Microbiol 2020; 10:489. [PMID: 33014899 PMCID: PMC7511630 DOI: 10.3389/fcimb.2020.00489] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 08/06/2020] [Indexed: 01/10/2023] Open
Abstract
Dengue is an acute febrile disease triggered by dengue virus. Dengue is the widespread and rapidly transmitted mosquito-borne viral disease of humans. Diverse symptoms and diseases due to Dengue virus (DENV) infection ranges from dengue fever, dengue hemorrhagic fever (life-threatening) and dengue shock syndrome characterized by shock, endothelial dysfunction and vascular leakage. Several studies have linked the severity of dengue with the induction of inflammasome. DENV activates the NLRP3-specific inflammasome in DENV infected human patients, mice; specifically, mouse bone marrow derived macrophages (BMDMs), dendritic cells, endothelial cells, human peripheral blood mononuclear cells (PBMCs), keratinocytes, monocyte-differentiated macrophages (THP-1), and platelets. Dengue virus mediated inflammasome initiates the maturation of IL-1β and IL-18, which are critical for dengue pathology and inflammatory response. Several studies have reported the molecular mechanism through which (host and viral factors) dengue induces inflammasome, unravels the possible mechanisms of DENV pathogenesis and sets up the stage for the advancement of DENV therapeutics. In this perspective article, we discuss the potential implications and our understanding of inflammasome mechanisms of dengue virus and highlight research areas that have potential to inhibit the pathogenesis of viral diseases, specifically for dengue.
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Affiliation(s)
- Gaurav Shrivastava
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, United States
| | - Paola Carolina Valenzuela Leon
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, United States
| | - Eric Calvo
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, United States
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15
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Shiryaev VA, Klimochkin YN. Heterocyclic Inhibitors of Viroporins in the Design of Antiviral Compounds. Chem Heterocycl Compd (N Y) 2020; 56:626-635. [PMID: 32836315 PMCID: PMC7366462 DOI: 10.1007/s10593-020-02712-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 04/06/2020] [Indexed: 12/19/2022]
Abstract
Ion channels of viruses (viroporins) represent a common type of protein targets for drugs. The relative simplicity of channel architecture allows convenient computational modeling and enables virtual search for new inhibitors. In this review, we analyze the data published over the last 10 years on known ion channels of viruses that cause socially significant diseases. The effectiveness of inhibition by various types of heterocyclic compounds of the viroporins of influenza virus, hepatitis С virus, human immunodeficiency virus, human papillomaviruses, coronaviruses, and respiratory syncytial virus is discussed. The presented material highlights the promise held by the search for heterocyclic antiviral compounds that act by inhibition of viroporins.
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Affiliation(s)
- Vadim A Shiryaev
- Samara State Technical University, 244 Molodogvardeiskaya St, Samara, 443100 Russia
| | - Yuri N Klimochkin
- Samara State Technical University, 244 Molodogvardeiskaya St, Samara, 443100 Russia
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16
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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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17
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Shrivastava G, Visoso-Carvajal G, Garcia-Cordero J, Leon-Juarez M, Chavez-Munguia B, Lopez T, Nava P, Villegas-Sepulveda N, Cedillo-Barron L. Dengue Virus Serotype 2 and Its Non-Structural Proteins 2A and 2B Activate NLRP3 Inflammasome. Front Immunol 2020; 11:352. [PMID: 32210961 PMCID: PMC7076137 DOI: 10.3389/fimmu.2020.00352] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 02/13/2020] [Indexed: 12/12/2022] Open
Abstract
Dengue is the most prevalent and rapidly transmitted mosquito-borne viral disease of humans. One of the fundamental innate immune responses to viral infections includes the processing and release of pro-inflammatory cytokines such as interleukin (IL-1β and IL-18) through the activation of inflammasome. Dengue virus stimulates the Nod-like receptor (NLRP3-specific inflammasome), however, the specific mechanism(s) by which dengue virus activates the NLRP3 inflammasome is unknown. In this study, we investigated the activation of the NLRP3 inflammasome in endothelial cells (HMEC-1) following dengue virus infection. Our results showed that dengue infection as well as the NS2A and NS2B protein expression increase the NLRP3 inflammasome activation, and further apoptosis-associated speck-like protein containing caspase recruitment domain (ASC) oligomerization, and IL-1β secretion through caspase-1 activation. Specifically, we have demonstrated that NS2A and NS2B, two proteins of dengue virus that behave as putative viroporins, were sufficient to stimulate the NLRP3 inflammasome complex in lipopolysaccharide (LPS)-primed endothelial cells. In summary, our observations provide insight into the dengue-induced inflammatory response mechanism and highlight the importance of DENV-2 NS2A and NS2B proteins in activation of the NLRP3 inflammasome during dengue virus infection.
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Affiliation(s)
- Gaurav Shrivastava
- Departmento de Biomedicina Molecular Centro de Investigación y Estudios Avanzados-Instituto Politécnico Nacional, Mexico City, Mexico
| | - Giovani Visoso-Carvajal
- Departmento de Biomedicina Molecular Centro de Investigación y Estudios Avanzados-Instituto Politécnico Nacional, Mexico City, Mexico
| | - Julio Garcia-Cordero
- Departmento de Biomedicina Molecular Centro de Investigación y Estudios Avanzados-Instituto Politécnico Nacional, Mexico City, Mexico
| | - Moisés Leon-Juarez
- Departamento de Inmunobioquímica, Instituto Nacional de Perinatología, Mexico City, Mexico
| | - Bibiana Chavez-Munguia
- Departamento de Infectomica y Biologia Molecular, Centro de Investigación y Estudios Avanzados-Instituto Politécnico Nacional, Mexico City, Mexico
| | - Tomas Lopez
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, UNAM Cuernavaca, Cuernavaca, Mexico
| | - Porfirio Nava
- Departamento de Fisiologia, Biofisica y Neurociencias, Cinvestav Zacatenco, Mexico City, Mexico
| | - Nicolás Villegas-Sepulveda
- Departmento de Biomedicina Molecular Centro de Investigación y Estudios Avanzados-Instituto Politécnico Nacional, Mexico City, Mexico
| | - Leticia Cedillo-Barron
- Departmento de Biomedicina Molecular Centro de Investigación y Estudios Avanzados-Instituto Politécnico Nacional, Mexico City, Mexico
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18
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Varasteh Moradi S, Gagoski D, Mureev S, Walden P, McMahon KA, Parton RG, Johnston WA, Alexandrov K. Mapping Interactions among Cell-Free Expressed Zika Virus Proteins. J Proteome Res 2020; 19:1522-1532. [DOI: 10.1021/acs.jproteome.9b00771] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Shayli Varasteh Moradi
- CSIRO-QUT Synthetic Biology Alliance, Centre for Tropical Crops and Bio-commodities, Queensland University of Technology, Brisbane QLD 4001, Australia
| | - Dejan Gagoski
- Queensland Brain Institute, The University of Queensland, St Lucia, Brisbane QLD 4072, Australia
| | - Sergey Mureev
- CSIRO-QUT Synthetic Biology Alliance, Centre for Tropical Crops and Bio-commodities, Queensland University of Technology, Brisbane QLD 4001, Australia
| | - Patricia Walden
- CSIRO-QUT Synthetic Biology Alliance, Centre for Tropical Crops and Bio-commodities, Queensland University of Technology, Brisbane QLD 4001, Australia
| | - Kerrie-Ann McMahon
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Brisbane QLD 4072, Australia
| | - Robert G. Parton
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Brisbane QLD 4072, Australia
- Centre for Microscopy and Microanalysis, The University of Queensland, St Lucia, Brisbane QLD 4072, Australia
| | - Wayne A. Johnston
- CSIRO-QUT Synthetic Biology Alliance, Centre for Tropical Crops and Bio-commodities, Queensland University of Technology, Brisbane QLD 4001, Australia
| | - Kirill Alexandrov
- CSIRO-QUT Synthetic Biology Alliance, Centre for Tropical Crops and Bio-commodities, Queensland University of Technology, Brisbane QLD 4001, Australia
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19
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Nasar S, Rashid N, Iftikhar S. Dengue proteins with their role in pathogenesis, and strategies for developing an effective anti-dengue treatment: A review. J Med Virol 2019; 92:941-955. [PMID: 31784997 DOI: 10.1002/jmv.25646] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 11/26/2019] [Indexed: 12/16/2022]
Abstract
Dengue virus is an arbovirus belonging to class Flaviviridae Its clinical manifestation ranges from asymptomatic to extreme conditions (dengue hemorrhagic fever/dengue shock syndrome). A lot of research has been done on this ailment, yet there is no effective treatment available for the disease. This review provides the systematic understanding of all dengue proteins, role of its structural proteins (C-protein, E-protein, prM) in virus entry, assembly, and secretion in host cell, and nonstructural proteins (NS1, NS2a, NS2b, NS3, NS4a, NS4b, and NS5) in viral assembly, replication, and immune evasion during dengue progression and pathogenesis. Furthermore, the review has highlighted the controversies related to the only commercially available dengue vaccine, that is, Dengvaxia, and the risk associated with it. Lastly, it provides an insight regarding various approaches for developing an effective anti-dengue treatment.
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Affiliation(s)
- Sitara Nasar
- School of Biological Sciences, University of the Punjab, Lahore, Pakistan
| | - Naeem Rashid
- School of Biological Sciences, University of the Punjab, Lahore, Pakistan
| | - Saima Iftikhar
- School of Biological Sciences, University of the Punjab, Lahore, Pakistan
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20
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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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21
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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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22
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Gopala Reddy SB, Chin WX, Shivananju NS. Dengue virus NS2 and NS4: Minor proteins, mammoth roles. Biochem Pharmacol 2018; 154:54-63. [PMID: 29674002 DOI: 10.1016/j.bcp.2018.04.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Accepted: 04/10/2018] [Indexed: 12/11/2022]
Abstract
Despite the ever-increasing global incidence of dengue fever, there are no specific chemotherapy regimens for its treatment. Structural studies on dengue virus (DENV) proteins have revealed potential drug targets. Major DENV proteins such as the envelope protein and non-structural (NS) proteins 3 and 5 have been extensively investigated in antiviral studies, but with limited success in vitro. However, the minor NS proteins NS2 and NS4 have remained relatively underreported. Emerging evidence indicating their indispensable roles in virus propagation and host immunomodulation should encourage us to target these proteins for drug discovery. This review covers current knowledge on DENV NS2 and NS4 proteins from structural and functional perspectives and assesses their potential as targets for antiviral design. Antiviral targets in NS2A include surface-exposed transmembrane regions involved in pathogenesis, while those in NS2B include protease-binding sites in a conserved hydrophilic domain. Ideal drug targets in NS4A include helix α4 and the PEPEKQR sequence, which are essential for NS4A-2K cleavage and NS4A-NS4B association, respectively. In NS4B, the cytoplasmic loop connecting helices α5 and α7 is an attractive target for antiviral design owing to its role in dimerization and NS4B-NS3 interaction. Findings implicating NS2A, NS2B, and NS4A in membrane-modulation and viroporin-like activities indicate an opportunity to target these proteins by disrupting their association with membrane lipids. Despite the lack of 3D structural data, recent topological findings and progress in structure-prediction methods should be sufficient impetus for targeting NS2 and NS4 for drug design.
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Affiliation(s)
- Sindhoora Bhargavi Gopala Reddy
- Department of Biotechnology, Sri Jayachamarajendra College of Engineering, JSS Science and Technology University, JSS TEI Campus, Mysuru 57006, Karnataka, India
| | - Wei-Xin Chin
- Laboratory of Molecular RNA Virology and Antiviral Strategies, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - Nanjunda Swamy Shivananju
- Department of Biotechnology, Sri Jayachamarajendra College of Engineering, JSS Science and Technology University, JSS TEI Campus, Mysuru 57006, Karnataka, India.
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23
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Perry JW, Chen Y, Speliotes E, Tai AW. Functional Analysis of the Dengue Virus Genome Using an Insertional Mutagenesis Screen. J Virol 2018; 92:e02085-17. [PMID: 29321321 PMCID: PMC5972875 DOI: 10.1128/jvi.02085-17] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 01/03/2018] [Indexed: 12/29/2022] Open
Abstract
In the last few decades, dengue virus, an arbovirus, has spread to over 120 countries. Although a vaccine has been approved in some countries, limitations on its effectiveness and a lack of effective antiviral treatments reinforce the need for additional research. The functions of several viral nonstructural proteins are essentially unknown. To better understand the functions of these proteins and thus dengue virus pathogenesis, we embarked on a genomewide transposon mutagenesis screen with next-generation sequencing to determine sites in the viral genome that tolerate 15-nucleotide insertions. Using this approach, we generated support for several published predicted transmembrane and enzymatic domains. Next, we created 7 mutants containing the 15-nucleotide insertion from the original selection and found 6 of them were capable of replication in both mammalian and mosquito tissue culture cells. Interestingly, one mutation had a significant impairment of viral assembly, and this mutation may lead to a better understanding of viral assembly and release. In addition, we created a fully infectious virus expressing a functionally tagged NS4B protein, which will provide a much-needed tool to elucidate the role of NS4B in viral pathogenesis.IMPORTANCE Dengue virus is a mosquito-borne virus distributed in tropical and subtropical regions globally that can result in hospitalization and even death in some cases. Although a vaccine exists, its limitations and a lack of approved antiviral treatments highlight our limited understanding of dengue virus pathogenesis and host immunity. The functions of many viral proteins are poorly understood. We used a previously published approach using transposon mutagenesis to develop tools to study these proteins' functions by adding insertions randomly throughout the viral genomes. These genomes were transferred into cells, and infectious progeny were recovered to determine sites that tolerated insertions, as only the genomes that tolerated insertions would be able to propagate. Using these results, we created viruses with epitope tags, one in the viral structural protein Capsid and one in the viral nonstructural protein NS4B. Further investigation of these mutants may elucidate the roles of Capsid and NS4B during dengue virus infections.
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Affiliation(s)
- Jeffrey W Perry
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Yanhua Chen
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Elizabeth Speliotes
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Andrew W Tai
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA
- Medicine Service, Ann Arbor Veterans Administration Health System, Ann Arbor, Michigan, USA
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24
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Cedillo-Barrón L, García-Cordero J, Shrivastava G, Carrillo-Halfon S, León-Juárez M, Bustos Arriaga J, León Valenzuela P, Gutiérrez Castañeda B. The Role of Flaviviral Proteins in the Induction of Innate Immunity. Subcell Biochem 2018; 88:407-442. [PMID: 29900506 DOI: 10.1007/978-981-10-8456-0_17] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Flaviviruses are positive, single-stranded, enveloped cytoplasmic sense RNA viruses that cause a variety of important diseases worldwide. Among them, Zika virus, West Nile virus, Japanese encephalitis virus, and Dengue virus have the potential to cause severe disease. Extensive studies have been performed to elucidate the structure and replication strategies of flaviviruses, and current studies are aiming to unravel the complex molecular interactions between the virus and host during the very early stages of infection. The outcomes of viral infection and rapid establishment of the antiviral state, depends on viral detection by pathogen recognition receptors and rapid initiation of signalling cascades to induce an effective innate immune response. Extracellular and intracellular pathogen recognition receptors play a crucial role in detecting flavivirus infection and inducing a robust antiviral response. One of the main hallmarks of flaviviral nonstructural proteins is their multiple strategies to antagonise the interferon system. In this chapter, we summarize the molecular characteristics of flaviviral proteins and discuss how viral proteins target different components of the interferon signalling pathway by blocking phosphorylation, enhancing degradation, and downregulating the expression of major components of the Janus kinase/signal transducer and activator of transcription pathway. We also discuss how the interactions of viral proteins with host proteins facilitate viral pathogenesis. Due to the lack of antivirals or prophylactic treatments for many flaviviral infections, it is necessary to fully elucidate how these viruses disrupt cellular processes to influence pathogenesis and disease outcomes.
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Affiliation(s)
- L Cedillo-Barrón
- Departamento de Biomedicina Molecular, CINVESTAV IPN, México, D.F, Mexico.
| | - J García-Cordero
- Departamento de Biomedicina Molecular, CINVESTAV IPN, México, D.F, Mexico
| | - G Shrivastava
- Departamento de Biomedicina Molecular, CINVESTAV IPN, México, D.F, Mexico
| | - S Carrillo-Halfon
- Departamento de Biomedicina Molecular, CINVESTAV IPN, México, D.F, Mexico
| | - M León-Juárez
- Department of Immunobiochemistry, National Institute of Perinatology, México City, Mexico
| | - J Bustos Arriaga
- Unidad de Biomedicina. Facultad de Estudios Superiores-Iztacala, Universidad Nacional Autonoma de México, Edo. de México, Mexico
| | - Pc León Valenzuela
- Departamento de Biomedicina Molecular, CINVESTAV IPN, México, D.F, Mexico
| | - B Gutiérrez Castañeda
- Immunology Department UMF Facultad de Estudios Superiores-Iztacala, Universidad Nacional Autonoma de México, Edo. de México, Mexico
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