Animal Flaviviruses

Antiviral and anti-inflammatory activity of novel belladonna formulation against Japanese encephalitis virus via inhibition of p65 nuclear translocation and TNF-α mediated NF-kB signaling

Japanese encephalitis (JE) is a mosquito-borne flavivirus infection, a major cause of viral encephalitis in South-East Asia with a CFR of ~30% and no specific treatment. Therefore, a novel belladonna formulation (BCT) was prepared and its antiviral and anti-inflammatory activity was elucidated during Japanese encephalitis virus (JEV) infection. Anti-JEV role of BCT was investigated aiming to prevent the infection in the peripheral immune cells. Antiviral activity of BCT was evaluated by plaque reduction assay, cell survival and apoptosis assay. BCT-mediated reduction in JEV-envelope expression was measured by indirect immunofluorescence, RT-PCR and Western blot assays. NF-κB expression and p65 nuclear translocation assays were determined to explore the mechanism of the action of BCT. TNF-α level was measured to evaluate the anti-inflammatory role of BCT during JEV infection. Consequently, molecular docking was performed with the TRAF2-TRADD complex. Our data suggested that BCT treatment reduces the JEV-plaque formation, JEV-induced cytopathic effects and increases cell survival. The antiviral effect of BCT was confirmed by reduction in the JEV-envelope protein expression. Moreover, BCT treatment and prevents the NF-κB activation via preventing the nuclear translocation of p65 and reduces the TNF-α levels. Our molecular docking analysis suggested that belladonna alkaloids interfere with the TRAF2-TRADD complex that results in inhibition of TNF-induced NF-κB signaling. For the first time, our data suggested that BCT reduces JEV expression and interferes with TNF-induced NF-κB signaling, thereby increasing cell survival via preventing the p65 nuclear translocation and may be used for the treatment and prevention of JE.Abbreviation: CFR: Case fatality rate; CAM: Complementary and alternative medicines; COX-2: Cyclooxygenase-2; IκB: Inhibitor kappa B; JE: Japanese encephalitis; JEV: Japanese encephalitis virus; NF-κB: Nuclear factor kappa-light-chain-enhancer of activated B cells; ORF: Open reading frame; TNFR: Tumor necrosis factor receptor; TNF-α: Tumor necrosis factor-α; TRADD: TNFR1-associated death domain protein; TRAF2: TNF Receptor Associated Factor 2.

Antiviral Activity of Belladonna During Japanese Encephalitis Virus Infection via Inhibition of Microglia Activation and Inflammation Leading to Neuronal Cell Survival

Japanese encephalitis virus (JEV) is the main cause of viral encephalitis resulting in more than 68 000 clinical cases every year with case fatality rate as high as 30-40% for which no specific treatments are available. We have recently exhibited belladonna may be widely applicable for the treatment of various neurological disorders. Therefore, we developed a hydroalcoholic formulation of belladonna (B200) consisting of atropine and scopolamine and showed its antiviral efficacy against JEV infection. B200 treatment increases neuronal cell survival by reducing JEV induced cytopathic effects which were evident from significant reduction in necrotic cell population by flow-cytometry analysis and caspase 3 and 8 enzymatic activities. B200 treatment was found to reduce the intracellular JEV level observed by significant reduction in JEV-fluorescein isothiocyanate (FITC) expression in both neurons and microglia. Because microglia plays a crucial role in JEV pathogenesis, we further investigated the anti-JEV effects of B200 on human microglia cells and elucidated the mechanism of action by performing whole-transcriptome sequencing. Gene expression analysis revealed that B200 reduces the pro-apoptotic and inflammatory gene expression observed by significant reduction in BAD, BAX, CASP3, CASP8, IL1B, and CXCL10 and increase in IL10 responsive gene expression. Interestingly, our molecular docking analysis revealed that atropine and scopolamine interact with the His288 residue of NS3 protein, a crucial residue for RNA unwinding and ATPase activity that was further confirmed by degradation of NS3 protein. Drug likeness, ADME (absorption, distribution, metabolism, and excretion), and toxicity analysis further suggests that atropine and scopolamine both cross the blood-brain barrier, which is crucial for effective treatment of Japanese encephalitis (JE).