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Virus Research Dec 2023Flaviviruses are a major cause of viral diseases worldwide, for which effective treatments have yet to be discovered. The prion protein (PrPc) is abundantly expressed in...
Flaviviruses are a major cause of viral diseases worldwide, for which effective treatments have yet to be discovered. The prion protein (PrPc) is abundantly expressed in brain cells and has been shown to play a variety of roles, including neuroprotection, cell homeostasis, and regulation of cellular signaling. However, it is still unclear whether PrPc can protect against flaviviruses. In this study, we investigated the role of PrPc in regulating autophagy flux and its potential antiviral activity during Japanese encephalitis virus (JEV) infection. Our in vivo experiment showed that JEV was more lethal to the PrPc knocked out mice which was further supported by histological analysis, western blot and rtPCR results from infected mice brain samples. Role of PrPc against viral propagation in vitro was verified through cell survival study, protein expression and RNA replication analysis, and adenoviral vector assay by overexpressing PrPc. Further analysis indicated that after virus entry, PrPc inhibited autophagic flux that prevented JEV replication inside the host cell. Our results from in vivo and in vitro investigations demonstrate that prion protein effectively inhibited JEV propagation by regulating autophagy flux which is used by JEV to release its genetic material and replication after entering the host cell, suggesting that prion protein may be a promising therapeutic target for flavivirus infection.
Topics: Animals; Mice; Encephalitis Virus, Japanese; Prion Proteins; Cell Line; Encephalitis, Japanese; Antiviral Agents; Virus Replication
PubMed: 37858731
DOI: 10.1016/j.virusres.2023.199249 -
BioRxiv : the Preprint Server For... Dec 2023Japanese Encephalitis Virus (JEV) NS2B-NS3 is a protein complex composed of NS3 proteases and a NS2B cofactor. The N-terminal protease domain (180 residues) of NS3...
NS2B-D55E and NS2B-E65D Variations are Responsible for Differences in NS2B-NS3 Protease Activities Between Japanese Encephalitis Virus Genotype I and III in Fluorogenic Peptide Model.
Japanese Encephalitis Virus (JEV) NS2B-NS3 is a protein complex composed of NS3 proteases and a NS2B cofactor. The N-terminal protease domain (180 residues) of NS3 (NS3(pro)) interacts directly with a central 40-amino acid hydrophilic domain of NS2B (NS2B(H)) to form an active serine protease. In this study, the recombinant NS2B(H)-NS3(pro) proteases were prepared in and used to compare the enzymatic activity between genotype I (GI) and III (GIII) NS2B-NS3 proteases. The GI NS2B(H)-NS3(pro) was able to cleave the sites at internal C, NS2A/NS2B, NS2B/NS3 and NS3/NS4A junctions that were identical to the sites proteolytically processed by GIII NS2B(H)-NS3(pro). Analysis of the enzymatic activity of recombinant NS2B(H)-NS3(pro) proteases using a model of fluorogenic peptide substrate revealed that the proteolytical processing activity of GIII NS2B(H)-NS3(pro) was significantly higher than that of GI NS2B(H)-NS3(pro). There were eight amino acid variations between GI and GIII NS2B(H)-NS3(pro), which may be responsible for the difference in enzymatic activities between GI and GIII proteases. Therefore, recombinant mutants were generated by exchanging NS2B(H) and NS3(pro) domains between GI and GIII NS2B(H)-NS3(pro) and subjected to protease activity analysis. Substitution of NS2B(H) significantly altered the protease activities, as compared to the parental NS2B(H)-NS3(pro), suggesting that NS2B(H) played an essential role in regulation of NS3(pro) protease activity. To further identify the amino acids responsible for the difference in protease activities, multiple substitution mutants including the individual and combined mutations at the variant residue 55 and 65 of NS2B(H) were generated and subjected to protease activity analysis. Replacement of NS2B-55 and NS2B-65 of GI to GIII significantly increased the enzymatic activity of GI NS2B(H)-NS3(pro) protease, whereas mutation of NS2B-55 and NS2B-65 of GIII to GI remarkably reduced the enzymatic activity of GIII NS2B(H)-NS3(pro) protease. Overall, these data demonstrated that NS2B-55 and NS2B-65 variations in hydrophilic domain of NS2B co-contributed to the difference in NS2B(H)-NS3(pro) protease activities between GI and GIII. These observations gain an insight into the role of NS2B in regulation of NS3 protease activities, which is useful for understanding the replication of JEV GI and GIII viruses.
PubMed: 38105993
DOI: 10.1101/2023.12.08.570834 -
Biosensors Jul 2023The Japanese encephalitis virus (JEV) is prevalent in Asian countries, including Korea, Japan, China, Vietnam, and India. JEV is transmitted to humans by Culex...
The Japanese encephalitis virus (JEV) is prevalent in Asian countries, including Korea, Japan, China, Vietnam, and India. JEV is transmitted to humans by Culex mosquitoes. Despite extensive research efforts, no approved antiviral agents are currently available, although JE can be prevented by vaccination. DNA endonuclease-targeted CRISPR trans reporter (DETECTR) is a newly emerging CRISPR-Cas12a-based molecular diagnostic method combined with isothermal nucleic acid amplification. In this study, DETECTR with reverse transcription-recombinase polymerase amplification (RT-RPA) was effectively utilized for JEV diagnosis and detected down to 10 RNA copies for JEV genotype I (GI) and 1 × 10 copies for both GIII and GV, achieving similar sensitivity to RT-PCR while displaying no cross-reaction with other viruses. A one-tube, one-temperature format of DETECTR was further developed, and its efficiency compared with that of conventional DETECTR.
Topics: Humans; Animals; Encephalitis Virus, Japanese; CRISPR-Cas Systems; Antiviral Agents; China; Genotype
PubMed: 37622855
DOI: 10.3390/bios13080769 -
EBioMedicine Nov 2023Complex patterns of cross-reactivity exist between flaviviruses, yet there is no precise understanding of how sequential exposures due to flavivirus infections or...
Priming with Japanese encephalitis virus or yellow fever virus vaccination led to the recognition of multiple flaviviruses without boosting antibody responses induced by an inactivated Zika virus vaccine.
BACKGROUND
Complex patterns of cross-reactivity exist between flaviviruses, yet there is no precise understanding of how sequential exposures due to flavivirus infections or vaccinations impact subsequent antibody responses.
METHODS
We investigated whether B cell priming from Japanese encephalitis virus (JEV) or yellow fever virus (YFV) vaccination impacted binding and functional antibody responses to flaviviruses following vaccination with a Zika virus (ZIKV) purified inactivated virus (ZPIV) vaccine. Binding antibody responses and Fc gamma receptor engagement against 23 flavivirus antigens were characterized along with neutralization titres and Fc effector responses in 75 participants at six time points.
FINDINGS
We found no evidence that priming with JEV or YFV vaccines improved the magnitude of ZPIV induced antibody responses to ZIKV. Binding antibodies and Fc gamma receptor engagement to ZIKV antigens did not differ significantly across groups, while antibody-dependent cellular phagocytosis (ADCP) and neutralizing responses were higher in the naïve group than in the JEV and YFV primed groups following the second ZPIV immunization (p ≤ 0.02). After a third dose of ZPIV, ADCP responses remained higher in the naïve group than in the primed groups. However, priming affected the quality of the response following ZPIV vaccination, as primed individuals recognized a broader array of flavivirus antigens than individuals in the naïve group.
INTERPRETATION
While a priming vaccination to either JEV or YFV did not boost ZIKV-specific responses upon ZIKV vaccination, the qualitatively different responses elicited in the primed groups highlight the complexity in the cross-reactive antibody responses to flaviviruses.
FUNDING
This work was supported by a cooperative agreement between The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., and the U.S. Department of the Army [W81XWH-18-2-0040]. The work was also funded in part by the National Institute of Allergy and Infectious Diseases (NIAID) R01AI155983 to SJK and KM.
Topics: Humans; Zika Virus; Flavivirus; Yellow fever virus; Encephalitis Virus, Japanese; Zika Virus Infection; Vaccines, Inactivated; Antibody Formation; Receptors, IgG; Antibodies, Neutralizing; Antibodies, Viral; Vaccination; Antigens, Viral; Cross Reactions
PubMed: 37793212
DOI: 10.1016/j.ebiom.2023.104815 -
Pediatric Research Jan 2024This review utilizes quatitative methods and bibliometric data to analyse the trends of emerging and re-emerging vector-borne diseases, with a focus on their impact on... (Review)
Review
This review utilizes quatitative methods and bibliometric data to analyse the trends of emerging and re-emerging vector-borne diseases, with a focus on their impact on pediatric population. To conduct this analysis, a systematic search of PubMed articles from the past two decades was performed, specifically looking at 26 different vector-borne viruses listed in WHO and CDC list of vector-borne viruses. The review found that diseases like Dengue, Zika, West Nile, and Chikungunya were frequently discussed in the literature. On the other hand, diseases such as Tick-borne encephalitis, Rift Valley fever, Venezuelan equine encephalitis, Sindbis fever, Venezuelan equine encephalitis, Ross River virus, and Eastern equine encephalitis showed an upward trend in publications, indicating potential resurgence. In addition to discussing trends and patterns, the review delves into the clinical manifestations and long-term effects of the top 10 viruses in children. It highlights various factors including deforestation, urbanization, global travel, and immunosuppression that contribute to disease emergence and resurgence. To effectively combat these vector-borne diseases, continuous surveillance is crucial. The review also emphasizes the importance of increased vaccination efforts and targeted research to address the health challenges they pose. IMPACT: This review employs quantitative analysis of publications to elucidate trends in emerging pediatric vector-borne viral diseases over two decades. Dengue, the most prevalent of these diseases, has spread to new regions. New strains of Japanese Encephalitis have caused outbreaks. Resurgence of Tick-borne Encephalitis, West Nile, and Yellow Fever due to vaccine hesitancy has also transpired. Continuous global surveillance, increased vaccination, and research into novel therapeutics are imperative to combat the substantial morbidity and mortality burden these diseases pose for children worldwide.
Topics: Child; Humans; Dengue; Encephalitis, Tick-Borne; Encephalomyelitis, Venezuelan Equine; Zika Virus; Zika Virus Infection
PubMed: 37880334
DOI: 10.1038/s41390-023-02866-x -
Emerging Microbes & Infections Dec 2024Japanese encephalitis (JE), caused by the Japanese encephalitis virus (JEV), is a highly threatening disease with no specific treatment. Fortunately, the development of...
Japanese encephalitis (JE), caused by the Japanese encephalitis virus (JEV), is a highly threatening disease with no specific treatment. Fortunately, the development of vaccines has enabled effective defense against JE. However, re-emerging genotype V (GV) JEV poses a challenge as current vaccines are genotype III (GIII)-based and provide suboptimal protection. Given the isolation of GV JEVs from Malaysia, China, and the Republic of Korea, there is a concern about the potential for a broader outbreak. Under the hypothesis that a GV-based vaccine is necessary for effective defense against GV JEV, we developed a pentameric recombinant antigen using cholera toxin B as a scaffold and mucosal adjuvant, which was conjugated with the E protein domain III of GV by genetic fusion. This GV-based vaccine antigen induced a more effective immune response in mice against GV JEV isolates compared to GIII-based antigen and efficiently protected animals from lethal challenges. Furthermore, a bivalent vaccine approach, inoculating simultaneously with GIII- and GV-based antigens, showed protective efficacy against both GIII and GV JEVs. This strategy presents a promising avenue for comprehensive protection in regions facing the threat of diverse JEV genotypes, including both prevalent GIII and GI as well as emerging GV strains.
Topics: Encephalitis Virus, Japanese; Animals; Genotype; Encephalitis, Japanese; Japanese Encephalitis Vaccines; Mice; Antibodies, Viral; Humans; Mice, Inbred BALB C; Female; Antigens, Viral; Vaccine Efficacy; Cholera Toxin
PubMed: 38618740
DOI: 10.1080/22221751.2024.2343910 -
Virologica Sinica Feb 2024Ferroptosis is a newly discovered prototype of programmed cell death (PCD) driven by iron-dependent phospholipid peroxidation accumulation, and it has been linked to...
Ferroptosis is a newly discovered prototype of programmed cell death (PCD) driven by iron-dependent phospholipid peroxidation accumulation, and it has been linked to numerous organ injuries and degenerative pathologies. Although studies have shown that a variety of cell death processes contribute to JEV-induced neuroinflammation and neuronal injury, there is currently limited research on the specific involvement of ferroptosis. In this study, we explored the neuronal ferroptosis induced by JEV infection in vitro and in vivo. Our results indicated that JEV infection induces neuronal ferroptosis through inhibiting the function of the antioxidant system mediated by glutathione (GSH)/glutathione peroxidase 4 (GPX4), as well as by promoting lipid peroxidation mediated by yes-associated protein 1 (YAP1)/long-chain acyl-CoA synthetase 4 (ACSL4). Further analyses revealed that JEV E and prM proteins function as agonists, inducing ferroptosis. Moreover, we found that treatment with a ferroptosis inhibitor in JEV-infected mice reduces the viral titers and inflammation in the mouse brains, ultimately improving the survival rate of infected mice. In conclusion, our study unveils a critical role of ferroptosis in the pathogenesis of JEV, providing new ideas for the prevention and treatment of viral encephalitis.
Topics: Mice; Animals; Neuroinflammatory Diseases; Ferroptosis; Neurons; Encephalitis, Japanese; Apoptosis
PubMed: 38104890
DOI: 10.1016/j.virs.2023.12.004 -
Frontiers in Cellular and Infection... 2023West Nile virus (WNV) and Japanese encephalitis virus (JEV) are emerging mosquito-borne flaviviruses causing encephalitis globally. No specific drug or therapy exists to...
West Nile virus (WNV) and Japanese encephalitis virus (JEV) are emerging mosquito-borne flaviviruses causing encephalitis globally. No specific drug or therapy exists to treat flavivirus-induced neurological diseases. The lack of specific therapeutics underscores an urgent need to determine the function of important host factors involved in flavivirus replication and disease progression. Interleukin-6 (IL-6) upregulation has been observed during viral infections in both mice and humans, implying that it may influence the disease outcome significantly. Herein, we investigated the function of IL-6 in the pathogenesis of neurotropic flavivirus infections. First, we examined the role of IL-6 in flavivirus-infected human neuroblastoma cells, SK-N-SH, and found that IL-6 neutralization increased the WNV or JEV replication and inhibited the expression of key cytokines. We further evaluated the role of IL-6 by infecting primary mouse cells derived from IL-6 knockout (IL-6) mice and wild-type (WT) mice with WNV or JEV. The results exhibited increased virus yields in the cells lacking the IL-6 gene. Next, our approach revealed that IL-6 mice had significantly higher morbidity and mortality after subcutaneous infection with the pathogenic WNV NY99 or JEV Nakayama strain compared to WT mice. The non-pathogenic WNV Eg101 strain did not cause mortality in WT mice but resulted in 60% mortality in IL-6 mice, indicating that IL-6 is required for the survival of mice after the peripheral inoculation of WNV or JEV. We also observed significantly higher viremia and brain viral load in IL-6 mice than in WT mice. Subsequently, we explored innate immune responses in WT and IL-6 mice after WNV NY99 infection. Our data demonstrated that the IL-6 mice had reduced levels of key cytokines in the serum during early infection but elevated levels of proinflammatory cytokines in the brain later, along with suppressed anti-inflammatory cytokines. In addition, mRNA expression of IFN-α and IFN-β was significantly lower in the infected IL-6 mice. In conclusion, these data suggest that the lack of IL-6 exacerbates WNV or JEV infection and by causing an increase in virus replication and dysregulating host immune response.
Topics: Animals; Humans; Mice; Cytokines; Encephalitis Virus, Japanese; Flavivirus; Interleukin-6; West Nile Fever; West Nile virus
PubMed: 38053527
DOI: 10.3389/fcimb.2023.1275823 -
Rinsho Shinkeigaku = Clinical Neurology Aug 2023Recent studies have demonstrated that atypical parkinsonism can be presented in autoimmune encephalitis and paraneoplastic neurological syndromes. However, it is unclear... (Review)
Review
Recent studies have demonstrated that atypical parkinsonism can be presented in autoimmune encephalitis and paraneoplastic neurological syndromes. However, it is unclear which anti-neural antibodies are involved and when these diseases should be suspected. To address these clinical questions, we conducted a scoping review and analyzed 38 articles. The literature shows that many anti-neural antibodies, including unknown ones, have been reported in progressive supranuclear palsy, corticobasal syndrome, and multiple system atrophy. Moreover, the following symptoms and signs suggest the possibility of autoimmune encephalitis and paraneoplastic neurological syndromes: early onset, acute or subacute progression, the presence of a neoplasm, significant weight loss, abnormal cerebrospinal fluid findings, the absence of typical brain magnetic resonance imaging findings, and the existence of atypical physical examination signs.
Topics: Humans; Parkinsonian Disorders; Encephalitis; Paraneoplastic Syndromes; Supranuclear Palsy, Progressive; Autoimmune Diseases of the Nervous System
PubMed: 37518015
DOI: 10.5692/clinicalneurol.cn-001871 -
Acta Tropica Jul 2024Japanese encephalitis (JE) is a mosquito-borne disease with a spatial distribution that is linked to geo-environmental factors. The spatial distribution of JE cases and...
Japanese encephalitis (JE) is a mosquito-borne disease with a spatial distribution that is linked to geo-environmental factors. The spatial distribution of JE cases and correlated geo-environmental factors were investigated in two critical counties in southern and northern China. Based on maps, enhanced thematic mapper (ETM) remote sensing datasets from Landsat and spatial datasets of JE cases, spatial distribution and spatial cluster analyses of JE cases at the village scale were performed by using the standard deviational ellipse and Ripleys K-function. Global and regional spatial cluster analyses of JE cases were also performed by using Moran's index. Regression analysis was used to analyze the relationships between geo-environmental characteristics and the risk of JE cases. At the study sites, the JE cases were not spatially clustered at the village or district (global) level, whereas there was a spatial cluster at the district (local) level. Diversity-related features for JE patients at the district and village levels were detected at two sites. In the southern counties, the distance of a village from a road was related to the village-level JE risk (OR: 0.530, 95 CI: 0.297-0.947, P = 0.032), and the number of township-level JE cases was linked to the distance of the district center from the road (R =-0.467, P = 0.025) and road length (R = 0.516, P = 0.012) in the administrative area. In northern China, the modified normalized difference water index (MNDWI) in the 5 km buffer around the village was related to village-level JE risk (OR: 0.702, 95% CI: 0.524-0.940, P = 0.018), and the number of township-level JE cases was related to the MNDWI in the administrative region (R =-0.522, P = 0.038). This study elucidates the spatial distribution patterns of JE cases and risk, as well as correlated geo-environmental features, at various spatial scales. This study will significantly assist the JE control efforts of the local Centers for Disease Control and Prevention (CDC), which is the base-level CDC, particularly concerning the allocation of medicine and medical staff, the development of immunological plans, and the allocation of pesticides and other control measures for the mosquito vectors of JE.
Topics: China; Humans; Encephalitis, Japanese; Spatial Analysis; Cluster Analysis; Female; Male; Child; Adult; Adolescent; Middle Aged; Young Adult; Child, Preschool; Infant; Aged; Environment; Topography, Medical
PubMed: 38729328
DOI: 10.1016/j.actatropica.2024.107246