Role of microRNAs in pathogenesis of venezuelan equine encephalitis virus and development of antiviral strategies

Abstract

Venezuelan equine encephalitis virus is a member of the alphavirus family and genus togaviridae. These viruses are mosquito-borne viruses and can cause fatal human diseases. VEEV can be easily spread through aerosol and has been weaponized making it a potential biothreat agent. MicroRNAs (miRNA) are a class of small (19-28nt) endogenous RNA molecules which have been proven to be key regulators of gene expression. MiRNAs modulate gene expression either by transcriptional blocking or by translational repression and have been shown to play an important role in early development and differentiation. newlineRole of microRNAs in the pathology of alphaviruses and more specifically VEEV has not been studied. In this research work we have studied the role of microRNAs in both in vitro and in vivo system. We identified miRNAs which can play crucial role in regulating the inflammation, viral entry and virus replication from our in vitro and in vivo results. MiRNAs modulation specific for cells of blood brain barrier indicated a role of these cells in viral entry into brain. Detailed studies revealed that VEEV infects endothelial cells of blood vessels and may present an additional viral entry route in the brain. Based on the leads from in vitro miRNA expression data, we further studied the role of phosphatidylinositol 3-Kinase-AKT pathway in VEEV infection. It was concluded that this pathway is very critical in the initial phase of the virus replication and blocking the pathway results in impaired virus replication. newlineMoreover, currently there are no FDA approved antivirals or vaccines are available for therapeutic and prophylaxis respectively. We have used various antiviral approaches including known antiviral compounds siRNA and artificial miRNAs and evaluated their therapeutic potential in response to VEEV infection. Data demonstrated that siRNA and miRNA effectively inhibited VEEV replication in vitro. The protection in case of artificial miRNAs appears to be newlinev newlinebetter in comparison to siRNA mediated transcriptional inhibition.