miR-301a mediated immune evasion by Japanese encephalitis virus

Abstract

Japanese encephalitis virus (JEV) is the most leading cause of acute viral encephalitis in Asia-Pacific region. It principally targets central nervous system (CNS) and is clinically manifested by headache, vomiting, impaired consciousness, and often seizures. Approximately, 20-30% of patients die annually and nearly half of the survivors were left with permanent neurological sequelae [1]. Although multiple vaccines are available, JEV cases are continuously being reported every year. There are no effective antiviral therapies and treatment is mainly supportive to relieve the clinical symptoms. Amongst the important reasons of failure to control viral infection is their ability to adopt modified strategy to escape host immune response. Antiviral innate immunity includes induced expression of type I interferons (IFNs) is the most vital and primary part of host immune system to deliver first line of defence against virus. Though it is a spontaneous response to invading virus, expression of innate immune molecules is reported to be influenced by several gene regulatory mechanisms including post-transcriptional regulation by microRNAs (miRNAs). miRNAs are small non-coding RNA molecules that have been identified as a key regulator in almost every cellular processes. In case of viral infections, they serve as a fine-tuner in regulation of both cellular and viral gene expression as evidenced from some recent studies