scholarly journals Degradation of MicroRNA miR-466d-3p by Japanese Encephalitis Virus NS3 Facilitates Viral Replication and Interleukin-1β Expression

2020 ◽  
Vol 94 (15) ◽  
Author(s):  
Hui Jiang ◽  
Lige Bai ◽  
Lina Ji ◽  
Zhuofang Bai ◽  
Jianwei Su ◽  
...  
Keyword(s):  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Computational Models ◽  
Encephalitis Virus ◽  
Site Directed Mutagenesis ◽  
Interleukin 1Β ◽  
Mirna Regulation ◽  
Ns3 Protein ◽  
Virus Serotype

ABSTRACT Japanese encephalitis virus (JEV) infection alters microRNA (miRNA) expression in the central nervous system (CNS). However, the mechanism contributing to miRNA regulation in the CNS is not known. We discovered global degradation of mature miRNA in mouse brains and neuroblastoma (NA) cells after JEV infection. Integrative analysis of miRNAs and mRNAs suggested that several significantly downregulated miRNAs and their targeted mRNAs were clustered into an inflammation pathway. Transfection with miRNA 466d-3p (miR-466d-3p) decreased interleukin-1β (IL-1β) expression and inhibited JEV replication in NA cells. However, miR-466d-3p expression increased after JEV infection in the presence of cycloheximide, indicating that viral protein expression reduced miR-466d-3p expression. We generated all the JEV coding proteins and demonstrated NS3 helicase protein to be a potent miRNA suppressor. The NS3 proteins of Zika virus, West Nile virus, and dengue virus serotype 1 (DENV-1) and DENV-2 also decreased miR-466d-3p expression. Results from helicase-blocking assays and in vitro unwinding assays demonstrated that NS3 could unwind pre-miR-466d and induce miRNA dysfunction. Computational models and an RNA immunoprecipitation assay revealed arginine-rich domains of NS3 to be crucial for pre-miRNA binding and degradation of host miRNAs. Importantly, site-directed mutagenesis of conserved residues in NS3 revealed that R226G and R202W reduced the binding affinity and degradation of pre-miR-466d. These results expand the function of flavivirus helicases beyond unwinding duplex RNA to degrade pre-miRNAs. Hence, we revealed a new mechanism for NS3 in regulating miRNA pathways and promoting neuroinflammation. IMPORTANCE Host miRNAs have been reported to regulate JEV-induced inflammation in the CNS. We found that JEV infection could reduce expression of host miRNA. The helicase region of the NS3 protein bound specifically to miRNA precursors and could lead to incorrect unwinding of miRNA precursors, thereby reducing the expression of mature miRNAs. This observation led to two major findings. First, our results suggested that JEV NS3 protein induced miR-466d-3p degradation, which promoted IL-1β expression and JEV replication. Second, arginine molecules on NS3 were the main miRNA-binding sites, because we demonstrated that miRNA degradation was abolished if arginines at R226 and R202 were mutated. Our study provides new insights into the molecular mechanism of JEV and reveals several amino acid sites that could be mutated for a JEV vaccine.

scholarly journals Mouse and Human Monoclonal Antibodies Protect against Infection by Multiple Genotypes of Japanese Encephalitis Virus

mBio ◽  
2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Estefania Fernandez ◽  
Nurgun Kose ◽  
Melissa A. Edeling ◽  
Jagat Adhikari ◽  
Gopal Sapparapu ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Viral Encephalitis ◽  
Encephalitis Virus ◽  
Site Directed Mutagenesis ◽  
Genotype Distribution ◽  
Genotype I

ABSTRACTJapanese encephalitis virus (JEV) remains a leading cause of viral encephalitis worldwide. Although JEV-specific antibodies have been described, an assessment of their ability to neutralize multiple genotypes of JEV has been limited. Here, we describe the development of a panel of mouse and human neutralizing monoclonal antibodies (MAbs) that inhibit infection in cell culture of four different JEV genotypes tested. Mechanism-of-action studies showed that many of these MAbs inhibited infection at a postattachment step, including blockade of virus fusion. Mapping studies using site-directed mutagenesis and hydrogen-deuterium exchange with mass spectrometry revealed that the lateral ridge on domain III of the envelope protein was a primary recognition epitope for our panel of strongly neutralizing MAbs. Therapeutic studies in mice demonstrated protection against lethality caused by genotype I and III strains when MAbs were administered as a single dose even 5 days after infection. This information may inform the development of vaccines and therapeutic antibodies as emerging strains and genotypic shifts become more prevalent.IMPORTANCEAlthough Japanese encephalitis virus (JEV) is a vaccine-preventable cause of viral encephalitis, the inactivated and live attenuated platforms available are derived from strains belonging to a single genotype (GIII) due to its historical prevalence in areas of JEV epidemics. Related to this, studies with vaccines and antibodies have focused on assessing thein vitroandin vivoprotective responses to homologous or heterologous GIII strains. An epidemiological shift in JEV genotype distribution warrants the induction of broadly neutralizing antibody responses that inhibit infection of multiple JEV genotypes. Here, we generated a panel of mouse and human neutralizing monoclonal antibodies and evaluated their inhibitory activity, epitope location, and capacity for protection against multiple JEV genotypes in mice.

scholarly journals NS5 from Dengue Virus Serotype 2 Can Adopt a Conformation Analogous to That of Its Zika Virus and Japanese Encephalitis Virus Homologues

2019 ◽  
Vol 94 (1) ◽  
Author(s):  
Abbas El Sahili ◽  
Tingjin Sherryl Soh ◽  
Jonas Schiltz ◽  
Aïcha Gharbi-Ayachi ◽  
Cheah Chen Seh ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Zika Virus ◽  
Nonstructural Protein ◽  
Vaccine Design ◽  
Encephalitis Virus ◽  
Virus Serotype ◽  
In Cells

ABSTRACT Flavivirus nonstructural protein 5 (NS5) contains an N-terminal methyltransferase (MTase) domain and a C-terminal polymerase (RNA-dependent RNA polymerase [RdRp]) domain fused through a 9-amino-acid linker. While the individual NS5 domains are structurally conserved, in the full-length protein, their relative orientations fall into two classes: the NS5 proteins from Japanese encephalitis virus (JEV) and Zika virus (ZIKV) adopt one conformation, while the NS5 protein from dengue virus serotype 3 (DENV3) adopts another. Here, we report a crystallographic structure of NS5 from DENV2 in a conformation similar to the extended one seen in JEV and ZIKV NS5 crystal structures. Replacement of the DENV2 NS5 linker with DENV1, DENV3, DENV4, JEV, and ZIKV NS5 linkers had modest or minimal effects on in vitro DENV2 MTase and RdRp activities. Heterotypic DENV NS5 linkers attenuated DENV2 replicon growth in cells, while the JEV and ZIKV NS5 linkers abolished replication. Thus, the JEV and ZIKV linkers likely hindered essential DENV2 NS5 interactions with other viral or host proteins within the virus replicative complex. Overall, this work sheds light on the dynamics of the multifunctional flavivirus NS5 protein and its interdomain linker. Targeting the NS5 linker is a possible strategy for producing attenuated flavivirus strains for vaccine design. IMPORTANCE Flaviviruses include important human pathogens, such as dengue virus and Zika virus. NS5 is a nonstructural protein essential for flavivirus RNA replication with dual MTase and RdRp enzyme activities and thus constitutes a major drug target. Insights into NS5 structure, dynamics, and evolution should inform the development of antiviral inhibitors and vaccine design. We found that NS5 from DENV2 can adopt a conformation resembling that of NS5 from JEV and ZIKV. Replacement of the DENV2 NS5 linker with the JEV and ZIKV NS5 linkers abolished DENV2 replication in cells, without significantly impacting in vitro DENV2 NS5 enzymatic activities. We propose that heterotypic flavivirus NS5 linkers impede DENV2 NS5 protein-protein interactions that are essential for virus replication.

scholarly journals Potential Role of Birds in Japanese Encephalitis Virus Zoonotic Transmission and Genotype Shift

Viruses ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 357
Author(s):  
Muddassar Hameed ◽  
Abdul Wahaab ◽  
Mohsin Nawaz ◽  
Sawar Khan ◽  
Jawad Nazir ◽  
...  
Keyword(s):  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Encephalitis Virus ◽  
Zoonotic Transmission ◽  
In Vivo Studies ◽  
Genotype I ◽  
Genotype Iii

Japanese encephalitis (JE) is a vaccine-preventable disease caused by the Japanese encephalitis virus (JEV), which is primarily prevalent in Asia. JEV is a Flavivirus, classified into a single serotype with five genetically distinct genotypes (I, II, III, IV, and V). JEV genotype III (GIII) had been the most dominant strain and caused numerous outbreaks in the JEV endemic countries until 1990. However, recent data shows the emergence of JEV genotype I (GI) as a dominant genotype and it is gradually displacing GIII. The exact mechanism of this genotype displacement is still unclear. The virus can replicate in mosquito vectors and vertebrate hosts to maintain its zoonotic life cycle; pigs and aquatic wading birds act as an amplifying/reservoir hosts, and the humans and equines are dead-end hosts. The important role of pigs as an amplifying host for the JEV is well known. However, the influence of other domestic animals, especially birds, that live in high abundance and close proximity to the human is not well studied. Here, we strive to briefly highlight the role of birds in the JEV zoonotic transmission, discovery of birds as a natural reservoirs and amplifying host for JEV, species of birds susceptible to the JEV infection, and the proposed effect of JEV on the poultry industry in the future, a perspective that has been neglected for a long time. We also discuss the recent in vitro and in vivo studies that show that the newly emerged GI viruses replicated more efficiently in bird-derived cells and ducklings/chicks than GIII, and an important role of birds in the JEV genotype shift from GIII to GI.

scholarly journals ZBTB38 in Porcine Alveolar Macrophages Positively Regulates the Proliferation of Japanese Encephalitis Virus

2021 ◽  
Author(s):  
Yi Zheng ◽  
Yu-Yong Zhou ◽  
Chun-Xia Chai ◽  
San-Jie Cao ◽  
Qi-Gui Yan ◽  
...  
Keyword(s):  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Alveolar Macrophages ◽  
Encephalitis Virus ◽  
Porcine Alveolar Macrophage ◽  
Envelope Gene ◽  
Interacting Protein ◽  
Btb Domain ◽  
New Information ◽  
Ns3 Protein

Abstract Background Japanese encephalitis (JE) is an important zoonotic disease caused by Japanese encephalitis virus (JEV), and pigs are intermediate host of this disease. Previous studies have confirmed that JEV can proliferate in the respiratory tract of mice and spread through it. Therefore, this study aimed to screen the proteins interacting with JEV on porcine alveolar macrophage cell and verify its role in the proliferation of JEV.Methods and results Porcine alveolar macrophages cell line 3D4/21 were infected with JEV, and obvious cytopathic effect (CPE) was observed. Zinc finger and BTB domain containing 38 (ZBTB38) was screened out as an interacting protein using co-immunoprecipitation assay and validated through knockout and overexpression of ZBTB38 in 3D4/21 cells. The results demonstrated that loss of ZBTB38 function basically had no effect on the attachment and entry processes of JEV, while the transcription level of JEV envelope gene, the expression level of NS3 protein and the number of virions were all significantly down-regulated in the subsequent infection stage. Conclusion Overall, one core conclusion was drawn in this paper that ZBTB38 promotes the proliferation of JEV especially in the middle and late stages of infection. This study provides new information for understanding the pathogenic mechanism of JEV, especially the respiratory transmission caused by JEV infection.

scholarly journals Histidine at Residue 99 and the Transmembrane Region of the Precursor Membrane prM Protein Are Important for the prM-E Heterodimeric Complex Formation of Japanese Encephalitis Virus

2005 ◽  
Vol 79 (13) ◽  
pp. 8535-8544 ◽  
Author(s):  
Ying-Ju Lin ◽  
Suh-Chin Wu
Keyword(s):  
Complex Formation ◽  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Microscopic Analysis ◽  
Subcellular Location ◽  
Encephalitis Virus ◽  
Site Directed Mutagenesis ◽  
Single Amino Acid ◽  
Heterodimeric Complex ◽  
Prm Protein

ABSTRACT The formation of the flavivirus prM-E complex is an important step for the biogenesis of immature virions, which is followed by a subsequent cleavage of prM to M protein through cellular protease to result in the production and release of mature virions. In this study, the intracellular formation of the prM-E complex of Japanese encephalitis virus was investigated by baculovirus coexpression of prM and E in trans in Sf9 insect cells as analyzed by anti-E antibody immunoprecipitation and sucrose gradient sedimentation analysis. A series of carboxyl-terminally truncated prM mutant baculoviruses was constructed to demonstrate that the truncations of the transmembrane (TM) region resulted in a reduction of the formation of the stable prM-E complex by approximately 40% for the TM1 (at residues 130 to 147 [prM130-147]) truncation and 20% for TM2 (at prM153-167) truncation. Alanine-scanning site-directed mutagenesis on the prM99-103 region indicated that the His99 residue was the critical prM binding element for stable prM-E heterodimeric complex formation. The single amino acid mutation at the His99 residue of prM abolishing the prM-E interaction was not due to reduced expression or different subcellular location of the mutant prM protein involved in prM-E interactions as characterized by pulse-chase labeling and confocal scanning microscopic analysis. Recombinant subviral particles were detected in the Sf9 cell culture supernatants by baculovirus coexpression of prM and E proteins but not with the prM H99A mutant. Sequence alignment analysis was further conducted with different groups of flaviviruses to show that the prM H99 residues are generally conserved. Our findings are the first report to characterize the minimum binding elements of the prM protein that are involved in prM-E interactions of flaviviruses. This information, concerning a molecular framework for the prM protein, is considered to elucidate the structure/function relationship of the prM-E complex synthesis and provide the proper trajectory for flavivirus assembly and maturation.

scholarly journals Targeting of the Nasal Mucosa by Japanese Encephalitis Virus for Non-Vector-Borne Transmission

2018 ◽  
Vol 92 (24) ◽  
Author(s):  
Obdulio García-Nicolás ◽  
Roman O. Braun ◽  
Panagiota Milona ◽  
Marta Lewandowska ◽  
Ronald Dijkman ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Ex Vivo ◽  
Encephalitis Virus ◽  
Nasal Epithelium ◽  
Virus Shedding ◽  
Nasal Epithelial Cells ◽  
Vector Borne

ABSTRACTThe mosquito-borne Japanese encephalitis virus (JEV) causes severe central nervous system diseases and cycles betweenCulexmosquitoes and different vertebrates. For JEV and some other flaviviruses, oronasal transmission is described, but the mode of infection is unknown. Using nasal mucosal tissue explants and primary porcine nasal epithelial cells (NEC) at the air-liquid interface (ALI) and macrophages asex vivoandin vitromodels, we determined that the nasal epithelium could represent the route of entry and exit for JEV in pigs. Porcine NEC at the ALI exposed to with JEV resulted in apical and basolateral virus shedding and release of monocyte recruiting chemokines, indicating infection and replication in macrophages. Moreover, macrophages stimulated by alarmins, including interleukin-25, interleukin-33, and thymic stromal lymphopoietin, were more permissive to the JEV infection. Altogether, our data are important to understand the mechanism of non-vector-borne direct transmission of Japanese encephalitis virus in pigs.IMPORTANCEJEV, a main cause of severe viral encephalitis in humans, has a complex ecology composed of a mosquito-waterbird cycle and a cycle involving pigs, which amplifies virus transmission to mosquitoes, leading to increased human cases. JEV can be transmitted between pigs by contact in the absence of arthropod vectors. Moreover, virus or viral RNA is found in oronasal secretions and the nasal epithelium. Using nasal mucosa tissue explants and three-dimensional porcine nasal epithelial cells cultures and macrophages asex vivoandin vitromodels, we determined that the nasal epithelium could be a route of entry as well as exit for the virus. Infection of nasal epithelial cells resulted in apical and basolateral virus shedding and release of monocyte recruiting chemokines and therefore infection and replication in macrophages, which is favored by epithelial-cell-derived cytokines. The results are relevant to understand the mechanism of non-vector-borne direct transmission of JEV.

scholarly journals Amino Acid at Position 166 of NS2A in Japanese Encephalitis Virus (JEV) Is Associated with In Vitro Growth Characteristics of JEV

Viruses ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 709
Author(s):  
Shigeru Tajima ◽  
Satoshi Taniguchi ◽  
Eri Nakayama ◽  
Takahiro Maeki ◽  
Takuya Inagaki ◽  
...  
Keyword(s):  
Amino Acid ◽  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Neuroblastoma Cells ◽  
Encephalitis Virus ◽  
Growth Potential ◽  
Sequencing Analysis ◽  
Murine Neuroblastoma ◽  
Growth Ability

We previously showed that the growth ability of the Japanese encephalitis virus (JEV) genotype V (GV) strain Muar is clearly lower than that of the genotype I (GI) JEV strain Mie/41/2002 in murine neuroblastoma cells. Here, we sought to identify the region in GV JEV that is involved in its low growth potential in cultured cells. An intertypic virus containing the NS1-3 region of Muar in the Mie/41/2002 backbone (NS1-3Muar) exhibited a markedly diminished growth ability in murine neuroblastoma cells. Moreover, the growth rate of a Muar NS2A-bearing intertypic virus (NS2AMuar) was also similar to that of Muar in these cells, indicating that NS2A of Muar is one of the regions responsible for the Muar-specific growth ability in murine neuroblastoma cells. Sequencing analysis of murine neuroblastoma Neuro-2a cell-adapted NS1-3Muar virus clones revealed that His-to-Tyr mutation at position 166 of NS2A (NS2A166) could rescue the low replication ability of NS1-3Muar in Neuro-2a cells. Notably, a virus harboring a Tyr-to-His substitution at NS2A166 (NS2AY166H) showed a decreased growth ability relative to that of the parental virus Mie/41/2002, whereas an NS2AMuar-based mutant virus, NS2AMuar-H166Y, showed a higher growth ability than NS2AMuar in Neuro-2a cells. Thus, these results indicate that the NS2A166 amino acid in JEV is critical for the growth and tissue tropism of JEV in vitro.

scholarly journals NS1′ of Flaviviruses in the Japanese Encephalitis Virus Serogroup Is a Product of Ribosomal Frameshifting and Plays a Role in Viral Neuroinvasiveness

2009 ◽  
Vol 84 (3) ◽  
pp. 1641-1647 ◽  
Author(s):  
Ezequiel Balmori Melian ◽  
Edward Hinzman ◽  
Tomoko Nagasaki ◽  
Andrew E. Firth ◽  
Norma M. Wills ◽  
...  
Keyword(s):  
Japanese Encephalitis Virus ◽  
Japanese Encephalitis ◽  
Nonstructural Protein ◽  
Infectious Clone ◽  
Encephalitis Virus ◽  
Innate Immune ◽  
Site Directed Mutagenesis ◽  
Sequence Elements ◽  
Rna Pseudoknot ◽  
Frameshift Event

ABSTRACT Flavivirus NS1 is a nonstructural protein involved in virus replication and regulation of the innate immune response. Interestingly, a larger NS1-related protein, NS1′, is often detected during infection with the members of the Japanese encephalitis virus serogroup of flaviviruses. However, how NS1′ is made and what role it performs in the viral life cycle have not been determined. Here we provide experimental evidence that NS1′ is the product of a −1 ribosomal frameshift event that occurs at a conserved slippery heptanucleotide motif located near the beginning of the NS2A gene and is stimulated by a downstream RNA pseudoknot structure. Using site-directed mutagenesis of these sequence elements in an infectious clone of the Kunjin subtype of West Nile virus, we demonstrate that NS1′ plays a role in viral neuroinvasiveness.

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