Background: The West Nile Virus (WNV) has emerged as one of the most significant arboviral
infection in many parts of the world and is associated with the encephalitis affecting mainly
human and horses. In spite of the fact that the WNV is threat for the public health, there is no vaccine
or therapeutic available for the treatment of WNV.
Methods: In this study, we tested a novel RNA interference based technique to inhibit WNV replication
in Vero cells. Two siRNAs were designed against the NS2A and NS5 regions of WNV which are
highly conserved among Flaviviruses as it play important role in apoptosis and in viral replication respectively.
In addition to this, dual functional siRNA is designed by joining an immunostimulatroy
motif with the NS2A and NS5 specific siRNA. The antiviral activity was evaluated by detecting both
the infectious virus and its genome.
Results: The bifunctional siRNA resulted in significant reduction of virus titre in siRNA transfected
cells as compared to controls. The antiviral efficacy was most effective at 48hr post infection. These
results were in accordance with the quantitative RT-PCR assay revealing similar reduction in WNV
genomic RNA. The expression of housekeeping gene was not affected by the siRNA indicating no off
target effect and non-interference in cellular mechanism.
Conclusion: Thus, this bifunctional siRNA intervention paves the new way for therapeutic treatment
of WNV disease.