Transcriptional regulation and activation of the mitogen-activated protein kinase pathway after Japanese encephalitis virus infection in neuroblastoma cells

Japanese encephalitis virus (JEV), the most frequent and the single most important cause of encephalitis worldwide, has spread throughout most of Asia. For the development of appropriate and effective therapy, there is an immediate requirement to understand the role of host factors in JEV-induced neuropathogenesis. In the present study, we investigated the role of mitogen-activated protein kinases (MAPKs) in JEV infection of mouse neuroblastoma (N2A) cells. The MAPK pathway was studied at the transcriptional level to access the gene expression profile at different time points after JEV infection. The effector MAPK genes were also analyzed for protein expression and activation. Gene expression analysis showed a significant regulation of extracellular signal-regulated kinases (ERK)1, ERK2 and c-Jun N-terminal kinase (JNK)3 genes along with their downstream transcription factors such as Mef2c, c-Jun and Sfn. Experiments with the JNK inhibitor, SP600125, and the ERK inhibitor, PD98059, showed the involvement of JNK in JEV-induced caspase-3 activation and apoptosis, but ERK1/2 had no effect. Overall, our results show the transcriptional regulation of the MAPK pathway and the essential role of JNK in JEV-induced apoptosis in neuroblastoma cells. These findings provide a new insight into the role of the mitogen- and stress-activated kinases in JEV pathogenesis and opens up new avenues of therapeutics.