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1.
J Virol ; 98(5): e0011624, 2024 May 14.
Article En | MEDLINE | ID: mdl-38591880

Flaviviruses in the Japanese encephalitis virus (JEV) serogroup, such as JEV, West Nile virus, and St. Louis encephalitis virus, can cause severe neurological diseases. The nonstructural protein 1 (NS1) is a multifunctional protein of flavivirus that can be secreted by infected cells and circulate in the host bloodstream. NS1' is an additional form of NS1 protein with 52 amino acids extension at its carboxy-terminal and is produced exclusively by flaviviruses in the JEV serogroup. In this study, we demonstrated that the secreted form of both NS1 and NS1' can disrupt the blood-brain barrier (BBB) of mice, with NS1' exhibiting a stronger effect. Using the in vitro BBB model, we found that treatment of soluble recombinant JEV NS1 or NS1' protein increases the permeability of human brain microvascular endothelial cells (hBMECs) and leads to the degradation of tight junction proteins through the autophagy-lysosomal pathway. Consistently, NS1' protein exhibited a more pronounced effect compared to NS1 in these cellular processes. Further research revealed that the increased expression of macrophage migration inhibitory factor (MIF) is responsible for triggering autophagy after NS1 or NS1' treatment in hBMECs. In addition, TLR4 and NF-κB signaling was found to be involved in the activation of MIF transcription. Moreover, administering the MIF inhibitor has been shown to decrease viral loads and mitigate inflammation in the brains of mice infected with JEV. This research offers a novel perspective on the pathogenesis of JEV. In addition, the stronger effect of NS1' on disrupting the BBB compared to NS1 enhances our understanding of the mechanism by which flaviviruses in the JEV serogroup exhibit neurotropism.IMPORTANCEJapanese encephalitis (JE) is a significant viral encephalitis worldwide, caused by the JE virus (JEV). In some patients, the virus cannot be cleared in time, leading to the breach of the blood-brain barrier (BBB) and invasion of the central nervous system. This invasion may result in cognitive impairment, behavioral disturbances, and even death in both humans and animals. However, the mechanism by which JEV crosses the BBB remains unclear. Previous studies have shown that the flavivirus NS1 protein plays an important role in causing endothelial dysfunction. The NS1' protein is an elongated form of NS1 protein that is particularly produced by flaviviruses in the JEV serogroup. This study revealed that both the secreted NS1 and NS1' of JEV can disrupt the BBB by breaking down tight junction proteins through the autophagy-lysosomal pathway, and NS1' is found to have a stronger effect compared to NS1 in this process. In addition, JEV NS1 and NS1' can stimulate the expression of MIF, which triggers autophagy via the ERK signaling pathway, leading to damage to BBB. Our findings reveal a new function of JEV NS1 and NS1' in the disruption of BBB, thereby providing the potential therapeutic target for JE.


Autophagy , Blood-Brain Barrier , Encephalitis Virus, Japanese , Encephalitis, Japanese , Viral Nonstructural Proteins , Animals , Humans , Mice , Blood-Brain Barrier/virology , Blood-Brain Barrier/metabolism , Brain/virology , Brain/metabolism , Encephalitis Virus, Japanese/physiology , Encephalitis, Japanese/virology , Encephalitis, Japanese/metabolism , Endothelial Cells/virology , Endothelial Cells/metabolism , Macrophage Migration-Inhibitory Factors/metabolism , NF-kappa B/metabolism , Viral Nonstructural Proteins/metabolism
2.
Vaccines (Basel) ; 11(12)2023 Dec 15.
Article En | MEDLINE | ID: mdl-38140261

Feline calicivirus (FCV) is one of the most important pathogens causing upper respiratory tract diseases in cats, posing a serious health threat to these animals. At present, FCV is mainly prevented through vaccination, but the protective efficacy of vaccines in China is limited. In this study, based on the differences in capsid proteins of isolates from different regions in China, as reported in our previous studies, seven representative FCV epidemic strains were selected and tested for their viral titers, virulence, immunogenicity, and extensive cross-protection. Subsequently, vaccine strains were selected to prepare inactivated vaccines. The whole-genome sequencing and analysis results showed that these seven representative FCV strains and 144 reference strains fell into five groups (A, B, C, D, and E). The strains isolated in China mainly fall into groups C and D, exhibiting regional characteristics. These Chinese isolates had a distant evolutionary relationship and low homology with the current FCV-255 vaccine strain. The screened FCV-HB7 and FCV-HB10 strains displayed desirable in vitro culture characteristics, with the highest virus proliferation titers (109.5 TCID50/mL) at 36 h post inoculation at a dose of 0.01 MOI. All five cats infected intranasally with FCV-HB7 or FCV-HB10 strains showed obvious clinical symptoms of FCV. The symptoms of cats infected with the FCV-HB7 strain were more severe than those infected with the FCV-HB10 strain. Both the single-strain inactivated immunization and combined bivalent inactivated vaccine immunization of FCV-HB7 and FCV-HB10 induced high neutralizing antibody titers in five cats immunized. Moreover, bivalent inactivated vaccine immunization protected cats from FCV-HB7 and FCV-HB10 strains. The cross-neutralizing antibody titer against seven representative FCV epidemic strains achieved by combined bivalent inactivated vaccine immunization was higher than that achieved by single-strain immunization, which was much higher than that achieved by commercial vaccine FCV-255 strain immunization. The above results suggest that the FCV-HB7 and FCV-HB10 strains screened in this study have great potential to become vaccine strains with broad-spectrum protective efficacy. However, their immune protective efficacy needs to be further verified by multiple methods before clinical application.

3.
Mediators Inflamm ; 2022: 2078520, 2022.
Article En | MEDLINE | ID: mdl-35633654

Objective: The relative contribution of some products with prebiotic effects, such as inulin, together with medications specific to the human gut microbiome has not been comprehensively studied. The present study determined the potential for manipulating populations in the gut microbiome using inulin alone and combined with other agents in individuals with metabolic syndrome (MetS). The study also assessed whether there is relationship variability in multiple clinical parameters in response to intervention with the changes in the gut milieu. Participants/Methods. This single-centre, single-blinded, randomised community-based pilot trial randomly assigned 60 patients (mean age, 46.3 y and male, 43%) with MetS to receive either inulin, inulin+traditional Chinese medicine (TCM), or inulin+metformin for 6 months. Lipid profiles, blood glucose, and uric acid (UA) levels were analysed in venous blood samples collected after overnight fast of 8 h at baseline and at the end of the follow-up period. Microbiota from stool samples were taxonomically analysed using 16S RNA amplicon sequencing, and an integrative analysis was conducted on microbiome and responsiveness data at 6 months. Results: The results of 16S rRNA sequencing showed that inulin resulted in a higher proportion of Bacteroides at the endpoint compared with inulin+TCM and inulin+metformin (p = 0.024). More Romboutsia (p = 0.043), Streptococcus (p < 0.001), and Holdemanella (p = 0.011) were found in inulin+TCM and inulin+metformin samples. We further identified gut microbiota relationships with lipids, UA, and glucose that impact the development of MetS. Conclusion: Among the groups, inulin alone or combined with metformin or TCM altered specific gut microbiota taxa but not the general diversity. Accordingly, we analysed metabolites associated with microbiota that might provide more information about intrinsic differences. Consequently, a reliable method could be developed for treating metabolic syndrome in the future.


Gastrointestinal Microbiome , Metabolic Syndrome , Metformin , Female , Gastrointestinal Microbiome/physiology , Humans , Inulin/metabolism , Inulin/therapeutic use , Male , Metabolic Syndrome/drug therapy , Metformin/therapeutic use , Middle Aged , Pilot Projects , RNA, Ribosomal, 16S , Risk Factors
4.
Pathogens ; 11(4)2022 Apr 12.
Article En | MEDLINE | ID: mdl-35456135

Feline coronavirus (FCoV) infections present as one of two forms: a mild or symptom-less enteric infection (FEC) and a fatal systemic disease termed feline infectious peritonitis (FIP). The lack of epidemiology of FCoV in central China and the reason why different symptoms are caused by viruses of the same serotype have motivated this investigation. Clinical data of 81 suspected FIP cases, 116 diarrhea cases and 174 healthy cases were collected from veterinary hospitals using body cavity effusion or fecal samples. Risk factors, sequence comparison and phylogenetic studies were performed. The results indicated that FIPV was distinguished from FECV in the average hydrophobicity of amino acids among the cleavage sites of furin, as well as the mutation sites 23,531 and 23,537. FIPV included a higher minimal R-X-X-R recognition motif of furin (41.94%) than did FECV (9.1%). The serotype of FCoV was insignificantly correlated with FIP, and the clade 1 and clade 2 strains that appeared were unique to central China. Thus, it is hypothesized that this, along with the latent variables of an antigenic epitope at positions 1058 and 1060, as well as mutations at the S1/S2 sites, are important factors affecting FCoV transmission and pathogenicity.

5.
Virol Sin ; 37(1): 94-106, 2022 Feb.
Article En | MEDLINE | ID: mdl-35234626

Flaviviruses are important arthropod-borne pathogens that represent an immense global health problem. Their unprecedented epidemic rate and unpredictable clinical features underscore an urgent need for antiviral interventions. Dehydroepiandrosterone (DHEA) is a natural occurring adrenal-derived steroid in the human body that has been associated in protection against various infections. In the present study, the plaque assay based primary screening was conducted on 32 synthetic derivatives of DHEA against Japanese encephalitis virus (JEV) to identify potent anti-flaviviral compounds. Based on primary screening, HAAS-AV3026 and HAAS-AV3027 were selected as hits from DHEA derivatives that exhibited strong antiviral activity against JEV (IC50 â€‹= â€‹2.13 and 1.98 â€‹µmol/L, respectively) and Zika virus (ZIKV) (IC50 â€‹= â€‹3.73 and 3.42 â€‹µmol/L, respectively). Mechanism study indicates that HAAS-AV3026 and HAAS-AV3027 do not exhibit inhibitory effect on flavivirus binding and entry process, while significantly inhibit flavivirus infection at the replication stage. Moreover, indirect immunofluorescence assay, Western blot analyses, and quantitative reverse transcription-PCR (qRT-PCR) revealed a potent antiviral activity of DHEA derivatives hits against JEV and ZIKV in terms of inhibition of viral infection, protein production, and viral RNA synthesis in Vero cells. Taken together, our results may provide a basis for the development of new antivirals against flaviviruses.


Flavivirus Infections , Flavivirus , Zika Virus Infection , Zika Virus , Animals , Antiviral Agents/pharmacology , Chlorocebus aethiops , Dehydroepiandrosterone/pharmacology , Flavivirus Infections/drug therapy , Humans , Vero Cells , Virus Replication
6.
Microbiol Spectr ; 9(3): e0166121, 2021 12 22.
Article En | MEDLINE | ID: mdl-34756071

Type I interferon (IFN-I) is a key component of the host innate immune system. To establish efficient replication, viruses have developed several strategies to escape from the host IFN response. Japanese encephalitis virus (JEV) NS1', a larger NS1-related protein, is known to inhibit the mitochondrial antiviral signaling (MAVS)-mediated IFN-ß induction by increasing the binding of transcription factors (CREB and c-Rel) to the microRNA 22 (miRNA-22) promoter. However, the mechanism by which NS1' induces the recruitment of CREB and c-Rel onto the miRNA-22 promoter is unknown. Here, we found that JEV NS1' protein interacts with the host cyclin-dependent kinase 1 (CDK1) protein. Mechanistically, NS1' interrupts the CDC25C phosphatase-mediated dephosphorylation of CDK1, which prolongs the phosphorylation status of CDK1 and leads to the inhibition of MAVS-mediated IFN-ß induction. Furthermore, the CREB phosphorylation and c-Rel activation through the IκBα phosphorylation were observed to be enhanced upon the augmentation of CDK1 phosphorylation by NS1'. The abrogation of CDK1 activity by a small-molecule inhibitor significantly suppressed the JEV replication in vitro and in vivo. Moreover, the administration of CDK1 inhibitor protected the wild-type mice from JEV-induced lethality but showed no effect on the MAVS-/- mice challenged with JEV. In conclusion, our study provides new insight into the mechanism of JEV immune evasion, which may lead to the development of novel therapeutic options to treat JEV infection. IMPORTANCE Japanese encephalitis virus (JEV) is the main cause of acute human encephalitis in Asia. The unavailability of specific treatment for Japanese encephalitis demands a better understanding of the basic cellular mechanisms that contribute to the onset of disease. The present study identifies a novel interaction between the JEV NS1' protein and the cellular CDK1 protein, which facilitates the JEV replication by dampening the cellular antiviral response. This study sheds light on a novel mechanism of JEV replication, and thus our findings could be employed for developing new therapies against JEV infection.


CDC2 Protein Kinase/metabolism , Encephalitis Virus, Japanese/immunology , Immune Evasion/immunology , Interferon-beta/immunology , Viral Nonstructural Proteins/metabolism , Virus Replication/physiology , Animals , CDC2 Protein Kinase/antagonists & inhibitors , CREB-Binding Protein/metabolism , Cell Line, Tumor , Cricetinae , Encephalitis, Japanese/immunology , HeLa Cells , Humans , Immunity, Innate/immunology , Mice , Mice, Inbred C57BL , Mice, Knockout , MicroRNAs/genetics , NF-KappaB Inhibitor alpha/metabolism , Phosphorylation/genetics , Promoter Regions, Genetic/genetics , Proto-Oncogene Proteins c-rel/metabolism , cdc25 Phosphatases/metabolism
7.
Front Microbiol ; 12: 727236, 2021.
Article En | MEDLINE | ID: mdl-34690968

Flaviviruses are the major emerging arthropod-borne pathogens globally. However, there is still no practical anti-flavivirus approach. Therefore, existing and emerging flaviviruses desperately need active broad-spectrum drugs. In the present study, the antiviral effect of steroidal dehydroepiandrosterone (DHEA) and 23 synthetic derivatives against flaviviruses such as Japanese encephalitis virus (JEV), Zika virus (ZIKV), and Dengue virus (DENV) were appraised by examining the characteristics of virus infection both in vitro and in vivo. Our results revealed that AV1003, AV1004 and AV1017 were the most potent inhibitors of flavivirus propagation in cells. They mainly suppress the viral infection in the post-invasion stage in a dose-dependent manner. Furthermore, orally administered compound AV1004 protected mice from lethal JEV infection by increasing the survival rate and reducing the viral load in the brain of infected mice. These results indicate that the compound AV1004 might be a potential therapeutic drug against JEV infection. These DHEA derivatives may provide lead scaffolds for further design and synthesis of potential anti-flavivirus potential drugs.

8.
Antiviral Res ; 182: 104930, 2020 10.
Article En | MEDLINE | ID: mdl-32898585

Japanese encephalitis virus (JEV) is one of the most important culex transmitted-flaviviruses, which can cause encephalitis in humans. Although non-structural protein 1 (NS1) of JEV does not stimulate neutralizing antibodies, this protein can provide high immunoprotection in vivo. The protective epitopes and the protective mechanism of NS1 still remain unclear. In this study, we generated five different monoclonal antibodies (mAbs) targeting the NS1 protein of JEV. In vitro experiments revealed that none of these five antibodies neutralized the JEV infection. In mouse protection studies, one of these mAbs, designated 2B8, provided a therapeutic effect against JEV lethal challenge (70% survival rate). Using peptide mapping analysis, we found that mAb 2B8 reacted with the epitope 225PETHTLWGD233 in the NS1 protein, in which any mutations among amino acid residues T228, H229, L231 or W232 could cause binding failure of 2B8 to the NS1 protein. Furthermore, mice immunized with KLH-polypeptide (225PETHTLWGD233) showed reduced mortality following JEV challenge. Collectively, we found a new protective epitope in the JEV NS1 protein. These results may facilitate the development of therapeutic agent and subunit-based vaccines based on the NS1 protein.


Antibodies, Monoclonal/immunology , Antibodies, Viral/immunology , Encephalitis Virus, Japanese/immunology , Encephalitis, Japanese/prevention & control , Epitope Mapping , Epitopes/immunology , Viral Nonstructural Proteins/immunology , Animals , Binding Sites, Antibody , Cell Line , Cricetinae , Encephalitis, Japanese/immunology , Immunization , Kidney/cytology , Mice , Mice, Inbred BALB C , Peptides/administration & dosage , Peptides/immunology , Sf9 Cells , Spodoptera
9.
BMC Genomics ; 21(1): 409, 2020 Jun 18.
Article En | MEDLINE | ID: mdl-32552669

BACKGROUND: Japanese encephalitis virus (JEV) is one of the common causes of acute encephalitis in humans. Japanese encephalitis is characterized by the uncontrolled release of inflammatory cytokines, which ultimately results in neuronal cell damage. In recent years, with the advancement of high-throughput sequencing technology, studies have shown that circRNAs, by competing with endogenous miRNAs, play a vital role in the pathology of CNS diseases. However, it is unknown whether circRNAs participate in JEV-induced neuroinflammation. RESULTS: By employing Illumina RNA-sequencing, we identified 180 circRNAs and 58 miRNAs that showed significant differential expression in JEV-infected mice brain tissues. The functional enrichment analyses revealed that these differentially regulated circRNAs were predominantly related to neurotransmission, histone modifications, transcription misregulation, and inflammation-associated calcium signaling pathway. Our established competing endogenous RNA (ceRNA) interaction network suggested the correlation of several circRNAs, miRNAs, and mRNAs in regulating the inflammatory response during JEV infection. Among the predicted interactions, the correlation between circ_0000220, miR-326-3p, and BCL3/MK2/TRIM25 mRNAs was experimentally validated by knockdown or overexpression of the non-coding RNA entities in cultured mouse microglia. The knockdown of circ_0000220 or overexpression of miR-326-3p caused a lower production of JEV-induced inflammatory cytokines. CONCLUSIONS: Conclusively, our study provides new insights into the host response to JEV infection and proposes the circRNA-targeting therapeutic interventions to rein in Japanese encephalitis.


Encephalitis Virus, Japanese/pathogenicity , Encephalitis, Japanese/genetics , Exome Sequencing/methods , MicroRNAs/genetics , RNA, Circular/genetics , Animals , B-Cell Lymphoma 3 Protein/genetics , Cells, Cultured , DNA-Binding Proteins/genetics , Gene Expression Regulation , Gene Knockdown Techniques , Gene Regulatory Networks , High-Throughput Nucleotide Sequencing , Intracellular Signaling Peptides and Proteins/genetics , Mice , Microglia/chemistry , Microglia/cytology , Protein Serine-Threonine Kinases/genetics , Sequence Analysis, RNA/methods , Transcription Factors/genetics
10.
J Immunol ; 204(5): 1287-1298, 2020 03 01.
Article En | MEDLINE | ID: mdl-31996459

Japanese encephalitis virus (JEV) is a mosquito-borne Flavivirus that causes severe neurologic disease in humans. NS1' is a NS1-related protein only reported in the Japanese encephalitis serogroup members of Flavivirus It is produced through programmed -1 ribosomal frameshift in NS2A. Our previous study demonstrated that JEV NS1' could antagonize type I IFN (IFN-I) production, but the mechanism is still unclear. In the current study, we found that JEV NS1' inhibits the expression of MAVS, and knockdown of MAVS hampers inhibition of IFN-ß induction by NS1', suggesting that JEV NS1' inhibits IFN-I production by targeting MAVS. This finding is further supported by the result of the in vivo assay that showed the similar mortality caused by NS1'-deficient virus and its wild type virus in MAVS-deficient mice. Based on our previous sequencing results of noncoding RNA in JEV-infected cells, microRNA-22 (miR-22) was identified to be a key regulator for MAVS expression during JEV infection. Furthermore, we demonstrated that JEV NS1' could induce the expression of miR-22 by increasing the binding of transcriptional factors, CREB and c-Rel, to the promoter elements of miR-22. Taken together, our results reveal a novel mechanism by which JEV NS1' antagonizes host MAVS by regulating miR-22, thereby inhibiting the IFN-I production and facilitating viral replication.


Adaptor Proteins, Signal Transducing/immunology , Encephalitis Virus, Japanese/physiology , Interferon Type I/immunology , Viral Nonstructural Proteins/immunology , Virus Replication/immunology , Adaptor Proteins, Signal Transducing/genetics , Animals , Cricetinae , Frameshifting, Ribosomal/immunology , HEK293 Cells , HeLa Cells , Humans , Interferon Type I/genetics , Mice , Mice, Knockout , MicroRNAs/genetics , MicroRNAs/immunology , Viral Nonstructural Proteins/genetics , Virus Replication/genetics
11.
Viruses ; 11(11)2019 10 31.
Article En | MEDLINE | ID: mdl-31683742

Flaviviruses, such as Zika virus (ZIKV), Japanese encephalitis virus (JEV), Dengue virus (DENV), and West Nile virus (WNV), are important arthropod-borne pathogens that present an immense global health problem. Their unpredictable disease severity, unusual clinical features, and severe neurological manifestations underscore an urgent need for antiviral interventions. Furin, a host proprotein convertase, is a key contender in processing flavivirus prM protein to M protein, turning the inert virus to an infectious particle. For this reason, the current study was planned to evaluate the antiviral activity of decanoyl-Arg-Val-Lys-Arg-chloromethylketone, a specific furin inhibitor, against flaviviruses, including ZIKV and JEV. Analysis of viral proteins revealed a significant increase in the prM/E index of ZIKV or JEV in dec-RVKR-cmk-treated Vero cells compared to DMSO-treated control cells, indicating dec-RVKR-cmk inhibits prM cleavage. Plaque assay, qRT-PCR, and immunofluorescence assay revealed a strong antiviral activity of dec-RVKR-cmk against ZIKV and JEV in terms of the reduction in virus progeny titer and in viral RNA and protein production in both mammalian cells and mosquito cells. Time-of-drug addition assay revealed that the maximum reduction of virus titer was observed in post-infection treatment. Furthermore, our results showed that dec-RVKR-cmk exerts its inhibitory action on the virus release and next round infectivity but not on viral RNA replication. Taken together, our study highlights an interesting antiviral activity of dec-RVKR-cmk against flaviviruses.


Amino Acid Chloromethyl Ketones/pharmacology , Flavivirus/drug effects , Furin/antagonists & inhibitors , Viral Envelope Proteins , Animals , Antiviral Agents/pharmacology , Cell Line , Chlorocebus aethiops , Encephalitis Virus, Japanese/drug effects , Furin/metabolism , Vero Cells , Viral Envelope Proteins/drug effects , Viral Envelope Proteins/metabolism , Virus Release/drug effects , Virus Replication/drug effects , Zika Virus/drug effects
12.
Arch Virol ; 164(6): 1535-1542, 2019 Jun.
Article En | MEDLINE | ID: mdl-30900070

Japanese encephalitis virus (JEV) is a zoonotic pathogen transmitted by Culex mosquitoes and is the leading cause of viral encephalitis in humans. JEV infection of swine, which are the main amplifying hosts for JEV, can cause reproductive failure in sows; in boars it can cause testitis and infertility. The prevalence of JEV in swine is a continuous threat to human health. A practical diagnostic method for monitoring JEV infection in swine herds is essential for control of the disease in both swine and humans. Here, we have identified a high-affinity anti-JEV NS1 monoclonal antibody (mAb) by indirect ELISA and utilized it for the development of a blocking ELISA (bELISA). The optimal NS1 protein coating concentration (2 µg/mL) and mAb working concentration (1 µg/mL) were determined by checkerboard titration. One hundred ten JEV-antibody-negative serum samples were used to establish 34.03% inhibition as the cutoff value for a negative result. By the bELISA, seroconversion in 80% of newly JEV-vaccinated pigs was detected by 7 days post-immunization, while by the commercial envelope-protein-based iELISA, seroconversion was detected in 20% of the newly vaccinated pigs. We found 98.7% agreement between the bELISA and the commercial iELISA when we tested 157 field samples using both methods. From an epidemiological survey of swine serum collected between 2014 and 2016, we found that the average JEV seropositive rate in unvaccinated commodity pigs was 8.1%, and in vaccinated boars and sows, it was 67.6%.


Antibodies, Monoclonal/administration & dosage , Encephalitis Virus, Japanese/immunology , Encephalitis, Japanese/diagnosis , Swine Diseases/virology , Viral Nonstructural Proteins/immunology , Animals , Antibodies, Monoclonal/blood , Antibodies, Monoclonal/metabolism , Antibodies, Viral/administration & dosage , Antibodies, Viral/blood , Antibodies, Viral/metabolism , Chlorocebus aethiops , Cloning, Molecular , Encephalitis, Japanese/immunology , Encephalitis, Japanese/veterinary , Female , Seroconversion , Swine , Swine Diseases/diagnosis , Swine Diseases/immunology , Vaccination , Vero Cells , Viral Nonstructural Proteins/genetics
13.
Virol Sin ; 33(6): 515-523, 2018 Dec.
Article En | MEDLINE | ID: mdl-30542978

Japanese encephalitis virus (JEV) is a mosquito-borne virus and the major cause of viral encephalitis in Asia. NS1', a 52-amino acid C-terminal extension of NS1, is generated with a -1 programmed ribosomal frameshift and is only present in members of the Japanese encephalitis serogroup of flaviviruses. Previous studies demonstrated that NS1' plays a vital role in virulence, but the mechanism is unclear. In this study, an NS1' defected (rG66A) virus was generated. We found that rG66A virus was less virulent than its parent virus (pSA14) in wild-type mice. However, similar mortality caused by the two viruses was observed in an IFNAR knockout mouse model. Moreover, we found that rG66A virus induced a greater type I interferon (IFN) response than that by pSA14, and JEV NS1' significantly inhibited the production of IFN-ß and IFN-stimulated genes. Taken together, our results reveal that NS1' plays a vital role in blocking type I IFN production to help JEV evade antiviral immunity and benefit viral replication.


Encephalitis Virus, Japanese/pathogenicity , Encephalitis, Japanese/immunology , Interferon-beta/antagonists & inhibitors , Viral Nonstructural Proteins/immunology , A549 Cells , Animals , Cell Line , Chlorocebus aethiops , Cricetinae , Female , HeLa Cells , Humans , Immune Evasion , Interferon-beta/immunology , Mice , Mice, Knockout , Receptor, Interferon alpha-beta/deficiency , Receptor, Interferon alpha-beta/genetics , Vero Cells , Virulence , Virus Replication
14.
J Neuroinflammation ; 15(1): 238, 2018 Aug 25.
Article En | MEDLINE | ID: mdl-30144801

BACKGROUND: Overstimulation of glutamate receptors, especially neuronal N-methyl-D-aspartate receptor (NMDAR), mediates excitatory neurotoxicity in multiple neurodegenerative diseases. However, the role of NMDAR in the regulation of Japanese encephalitis virus (JEV)-mediated neuropathogenesis remains undisclosed. The primary objective of this study was to understand the function of NMDAR to JEV-induced neuronal cell damage and inflammation in the central nervous system. METHODS: The effect of JEV-induced NMDAR activation on the progression of Japanese encephalitis was evaluated using the primary mouse neuron/glia cultures and a mouse model of JEV infection. A high-affinity NMDAR antagonist MK-801 was employed to block the activity of NMDAR both in vitro and in vivo. The subsequent impact of NMDAR blockade was assessed by examining the neuronal cell death, glutamate and inflammatory cytokine production, and JEV-induced mice mortality. RESULTS: JEV infection enhanced the activity of NMDAR which eventually led to increased neuronal cell damage. The data obtained from our in vitro and in vivo assays demonstrated that NMDAR blockade significantly abrogated the neuronal cell death and inflammatory response triggered by JEV infection. Moreover, administration of NMDAR antagonist protected the mice from JEV-induced lethality. CONCLUSION: NMDAR plays an imperative role in regulating the JEV-induced neuronal cell damage and neuroinflammation. Thus, NMDAR targeting may constitute a captivating approach to rein in Japanese encephalitis.


Encephalitis Virus, Japanese/pathogenicity , Encephalitis, Japanese/pathology , Neurons/metabolism , Receptors, N-Methyl-D-Aspartate/metabolism , Animals , Annexin A5/metabolism , Caspase 3/metabolism , Cell Survival/drug effects , Cells, Cultured , Cytokines/genetics , Cytokines/metabolism , Disease Models, Animal , Dizocilpine Maleate/therapeutic use , Embryo, Mammalian , Encephalitis, Japanese/drug therapy , Excitatory Amino Acid Antagonists/therapeutic use , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Neuroglia/drug effects , Neuroglia/metabolism , Neuroglia/pathology , Neurons/pathology , Neurons/virology , Phosphopyruvate Hydratase/metabolism , Phosphorylation/drug effects
15.
Front Immunol ; 8: 1237, 2017.
Article En | MEDLINE | ID: mdl-29033949

Japanese encephalitis virus (JEV) is the leading cause of epidemic encephalitis worldwide. JEV-induced neuroinflammation is characterized by profound neuronal cells damage accompanied by activation of glial cells. Albeit long non-coding RNAs (lncRNAs) have been emerged as important regulatory RNAs with profound effects on various biological processes, it is unknown how lncRNAs regulate JEV-induced inflammation. Here, using microarray approach, we identified 618 lncRNAs and 1,007 mRNAs differentially expressed in JEV-infected mice brain. The functional annotation analysis revealed that differentially regulated transcripts were predominantly involved in various signaling pathways related to host immune and inflammatory responses. The lncRNAs with their potential to regulate JEV-induced inflammatory response were identified by constructing the lncRNA-mRNA coexpression network. Furthermore, silencing of the two selected lncRNAs (E52329 and N54010) resulted in reducing the phosphorylation of JNK and MKK4, which are known to be involved during inflammatory response. Collectively, we first demonstrated the transcriptomic landscape of lncRNAs in mice brain infected with JEV and analyzed the coexpression network of differentially regulated lncRNAs and mRNAs during JEV infection. Our results provide a better understanding of the host response to JEV infection and suggest that the identified lncRNAs may be used as potential therapeutic targets for the management of Japanese encephalitis.

16.
Sci Signal ; 9(448): ra98, 2016 10 04.
Article En | MEDLINE | ID: mdl-27703031

Japanese encephalitis virus (JEV) is the leading cause of epidemic encephalitis worldwide. The pathogenesis of JEV is linked to a robust inflammatory response in the central nervous system (CNS). Glial cells are the resident immune cells in the CNS and represent critical effectors of CNS inflammation. To obtain a global overview of signaling events in glial cells during JEV infection, we conducted phosphoproteomics profiling of a JEV-infected glial cell line. We identified 1816 phosphopeptides, corresponding to 1264 proteins, that exhibited a change in phosphorylation status upon JEV infection. Bioinformatics analysis revealed that these proteins were predominantly related to transcription regulation, signal transduction, the cell cycle, and the cytoskeleton. Kinase substrate motif revealed that substrates for c-Jun N-terminal kinase 1 (JNK1) were the most overrepresented, along with evidence of increased AKT1 and protein kinase A (PKA) signaling. Pharmacological inhibition of JNK, AKT, or PKA reduced the inflammatory response of cultured glial cells infected with JEV, as did knockdown of JNK1 or its target JUN. JEV genomic RNA was sufficient to activate JNK1 signaling in cultured glial cells. Of potential clinical relevance, we showed that inhibition of JNK signaling significantly attenuated the production of inflammatory cytokines in the brain and reduced lethality in JEV-infected mice, thereby suggesting that JNK signaling is a potential therapeutic target for the management of Japanese encephalitis.


Encephalitis Virus, Japanese/metabolism , Encephalitis, Japanese/metabolism , Mitogen-Activated Protein Kinase 8/metabolism , Phosphoproteins/metabolism , Signal Transduction , Animals , Cell Line, Tumor , Cyclic AMP-Dependent Protein Kinases/genetics , Cyclic AMP-Dependent Protein Kinases/metabolism , Encephalitis Virus, Japanese/genetics , Encephalitis, Japanese/genetics , Humans , Inflammation/genetics , Inflammation/metabolism , Mice , Mitogen-Activated Protein Kinase 8/genetics , Phosphoproteins/genetics , Proteomics , Proto-Oncogene Proteins c-akt/genetics , Proto-Oncogene Proteins c-akt/metabolism
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