Alpha-synuclein expression in neuron modulates the Japanese encephalitis virus infection

Abstract

AbstractJapanese encephalitis virus (JEV) stands as a prominent vector-borne zoonotic pathogen, displaying neurotropism and eliciting Parkinson’s disease (PD)-like symptoms among most symptomatic survivors. A characteristic feature of PD is aggregation of mutated α-synuclein (α-syn) that damages the dopaminergic neurons. Considering this link between JEV-induced PD-like symptoms and α-syn pathogenesis, we explored the role of α-syn in JEV infectivity in neuronal cells. Our investigation revealed significant increase in endogenous α-syn expression in JEV-infected cells. Additionally, treatment with exogenous α-syn (Exoα-syn) led to a substantial reduction in JEV replication, suggesting its anti-JEV effect. Furthermore, Exoα-syn treatment led to the upregulation of superoxide dismutase 1 (SOD1) and reduction in reactive oxygen species (ROS). The results were validated by endogenous α-syn-silencing, that decreased SOD1 level and raised ROS level in neuronal cells. Similarly, the SOD1 inhibition via LCS-1 also intensified ROS and JEV infection. Overall, our results suggest that α-syn exerts an anti-JEV effect by regulating protein involved in oxidative stress inside neuronal cells. This study contributes valuable insights into the interplay between α-syn expression and JEV infectivity, shedding light on avenues to further investigate the potential role of α-syn in JEV pathogenesis.ImportanceJapanese encephalitis virus (JEV) poses significant threat particularly to children. Despite extensive research efforts, the development of effective treatments against JEV has been impeded. One of the major setbacks is a lack of comprehensive understanding of neurotropism. The study focuses on alpha synuclein (α-syn), a neuronal protein, and aims to determine its role in JEV pathogenesis. Present study reveals that host cell upregulates α-syn in response of JEV infection. α-syn restrains JEV propagation by modulating superoxide dismutase 1 (SOD1) expression which further blocks JEV-induced ROS generation. Endogenous α-syn silencing led to decrease in SOD1 expression and increased viral titer. α-syn plays crucial role in counteracting oxidative stress through SOD1, which is essential for limiting JEV replication. This study provides broader implications for antiviral strategies and its possible role in neurodegenerative diseases; however, there is still much to explore, particularly regarding its aggregation kinetics in JEV infection.