Exaggerated levels of some specific TLRs, cytokines and chemokines in Japanese encephalitis infected BV2 and neuro 2A cell lines associated with worst outcome

Abstract

Japanese encephalitis (JE) disease, a viral brain fever is caused by Japanese encephalitis virus (JEV). Despite the availability of effective vaccines against this deadly infection, JE is the leading cause of epidemic viral encephalitis in children in South-east Asia. There is no treatment available for the JE disease which might be due to incomplete understanding of the pathogenesis of JE virus. The JEV infections lead to permanent neurological deficits even in those who survive from the infection. Activated microglia may play a potentially detrimental role by eliciting the expression of pro-inflammatory cytokines such as interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNF-α) influencing the surrounding brain tissue. Microglial activation, proinflammatory cytokine release and leukocytes trafficking are associated following JEV infection in central nervous system (CNS). How the pattern recognition receptors sense the viral nucleic acid and how the microglial and neuronal cells behaves following JEV infection is still unelucidated. There is scarcity of data on the expression levels of toll like receptors (TLRs), cytokines and chemokines in JEV infection in invitro model. To explore the molecular mechanisms of JEV infection of microglial cells and neuronal cells, we studied the expression profile of TLRs, cytokines and chemokines in JEV infected microglial cell line BV2 and Neuronal cell line Neuro 2A. For the present study, we developed the mouse model of encephalitis by intracerebral (IC) injection of JE virus for virus propagation, disease progression and damage study. Our results demonstrate the exaggerated release of some specific TLRs, cytokines and chemokines in invitro cell culture of microglial and Neuro 2A cell line, which are associated with bad outcome in invivo study.