The highly conserved 5′ untranslated region as an effective target towards the inhibition of Enterovirus 71 replication by unmodified and appropriate 2′-modified siRNAs

Background: enterovirus 71 (ev71) is a highly infectious agent that plays an etiological role in hand,foot,and mouth disease. it is associated with severe neurological complications and has caused significant mortalities in recent large-scale outbreaks. currently,no effective vaccine or specific clinical therapy is available against ev71. methods: unmodified 21 nucleotide small interfering rnas (sirnas) and classic 2′-modified (2′-o-methylation or 2′-fluoro modification) sirnas were designed to target highly conserved 5′ untranslated region (utr) of the ev71 genome and employed as anti-ev71 agents. real-time taqman rt-pcr,western blot analysis and plaque assays were carried out to evaluate specific viral inhibition by the sirnas. results: transfection of rhabdomyosarcoma (rd) cells with sirnas targeting the ev71 genomic 5′ utr significantly delayed and alleviated the cytopathic effects of ev71 infection,increased cell viability in ev71-infected rd cells. the inhibitory effect on ev71 replication was sequence-specific and dosage-dependent,with significant corresponding decreases in viral rna,vp1 protein and viral titer. appropriate 2′-modified sirnas exhibited similar rna interference (rnai) activity with dramatically increased serum stability in comparison with unmodified counterparts. conclusion: sequences were identified within the highly conserved 5′ utr that can be targeted to effectively inhibit ev71 replication through rnai strategies. appropriate 2′-modified sirnas provide a promising approach to optimizing sirnas to overcome barriers on rnai-based antiviral therapies for broader administration. © 2012 deng et al.; licensee biomed central ltd.