Pyruvate Kinase M2 regulates Japanese encephalitis virus replication by interacting with NS1 protein

Pyruvate kinase isoform M2 (PKM2) is a key modulator of glucose metabolism. While the major role of PKM2 is to facilitate the breakdown of glucose, it is potentially associated with other additional non-glycolytic functions as well. The role of PKM2 in the autoimmune response and inflammatory process is increasingly being acknowledged as a crucial modulator of cellular pathophysiological activity. However, its role in modulating viral replication has not been explored in detail. In the present study, we have shown a significant increase in endogenous PKM2 expression in JEV-infected mouse neuroblastoma cells. Furthermore, overexpression of PKM2 significantly reduced JEV replication, suggesting a negative effect of PKM2 on JEV replication. This was further confirmed by siRNA-mediated downregulation of endogenous PKM2 expression, which resulted in enhanced JEV replication. In silico studies revealed the potential interaction between PKM2 and NS1 protein of JEV. The microscopic studies also showed cellular colocalization of PKM2 and NS1 in the ER of infected cells. The interaction was further validated in vitro by co-immunoprecipitation assay. The present study suggests that PKM2 negatively regulates the JEV replication by its possible interaction with NS1. ImportanceJapanese encephalitis (JE) is a neuroinflammatory disease caused by the Japanese encephalitis virus (JEV). JE is a major threat to public health not only because it causes many deaths but also for its permanent neuropsychiatric sequelae in children. Out of all non-structural proteins of JEV, NS1 is highly immunogenic. A wide range of possible interactive partners has been identified for the NS1, many of those have been linked to immune evasion and regulating viral replication. In the current study, we have described a novel host cell factor, PKM2 modulating JEV replication by interacting with NS1 protein. Considering PKM2s central role in regulating host cell metabolism, our findings suggest a previously unrecognized role for PKM2 in JEV neuropathogenesis. The identification and characterization of previously unknown host factors, as well as the elucidation of their regulatory mechanisms, are of utmost importance in the development of innovative treatments and antivirals against JEV.