Targeting 2A protease by RNA interference attenuates coxsackieviral cytopathogenicity and promotes survival in highly susceptible mice

Background - Enteroviridae such as coxsackievirus B3 (CVB3) are important infectious agents involved in viral heart disease, hepatitis, and pancreatitis, but no specific antiviral therapy is available. Methods and Results - The aim of the present study was to evaluate the impact of RNA interference on viral replication, cytopathogenicity, and survival. Small interfering RNA ( siRNA) molecules were designed against the viral 2A region (siRNA-2A), which is considered to be highly conserved and essential for both virus maturation and host cytopathogenicity. siRNA-2A exhibited a significant protective effect on cell viability mediated by marked inhibition of CVB3 gene expression and viral replication. In highly susceptible type I interferon receptor - knockout mice, siRNA-2A led to significant reduction of viral tissue titers, attenuated tissue damage, and prolonged survival. Repeated siRNA-2A transfection was associated with a further improvement of survival. Various control siRNA molecules had no protective effect in vitro or in vivo. Conclusions - RNA interference directed against the 2A protease encoding genomic region effectively confers intracellular immunity toward CVB3-mediated cell injury and improves survival, suggesting a potential role for RNA interference for future treatment options targeting enteroviral diseases.