Potent inhibition of influenza B virus BM2 gene transcript by DNAzymes significantly reduce viral RNA translation and replication

INTRODUCTION:  The vaccine against influenza viruses needs to be updated annually due to frequent mutations in their genome. The influenza B virus BM2 ion channel protein is highly conserved and essentially required during the trafficking, assembly and budding processes of virus, thus an attractive target for designing antiviral drugs. DNAzymes (Dz’s) represent the most effective nucleic acid drug to date. They are stable as compared to their RNA counterparts and highly specific in action.

METHODS:  We designed several 10-23 DNAzymes (Dz’s) targeting different regions of the matrix gene (BM2) of influenza B viruses and analyzed their ability to specifically cleave the target RNA in both cell free systems as well as in cell culture using transient transfections. 

RESULTS:  RT-PCR and real-time RT-PCR assays showed significant 65% inhibition of BM2 gene of influenza B viruses upon specific Dz treatment. The transfection of MDCK cells with Dz showed reduced cytopathic effect caused by influenza B virus (B/Yamagata/1/73) and considerably reduced the BM2 protein expression for a comparatively longer duration of time. As expected, the mutant-Dz did not hinder in virus replication showing high level of specificity of designed Dz towards the target RNA. 

CONCLUSIONS:  Our results demonstrate substantial reduction in whole virus replication thereby paving new dimensions in antiviral therapy. Our study, for the first time, has documented antiviral potential of Dz against BM2 transcript of influenza B virus. Thus, we propose that the 10-23 DNAzymes may be used as selective and effective inhibitor of viral RNA replication, and can be explored further for development of a potent therapeutic agent against influenza infection.