Small Interfering RNAs against Human Enteroviral Infections

Much is known about the enteroviral life cycle, however, because of the emergence of resistant mutants, no effective specific drugs are available to treat enteroviral infections. RNA interference (RNAi) is a post-transcriptional, sequence-specific, gene-silencing defense mechanism of eukaryotic cells against viruses and transposons. It is an evolutionarily conserved mechanism for regulating gene expression which has the potential to be a therapeutic alternative to antiviral small molecule drugs. Small interfering RNAs (siRNAs) induce RNAi and are critical for the inhibition of RNA virus replication in the host cell. siRNAs are also important regulators of virus-host cell interactions. In this investigation we describe a relatively novel approach for using RNAi against CBVs by creating a siRNA pool covering different conserved CBV gene sequences. Many viruses have evolved mechanisms to inhibit RNAi cell defenses. A single nucleotide substitution in the RNAi target site within the viral genome can result in complete loss of interference, depending on the location and the nature of the resulting mismatch. Using polls of siRNAs inhibit the viruses which may escape single-site siRNA silencing by point mutations, overlapping the mutated target region. The polymerase complex of bacteriophage phi 6 is used to synthesize specific dsRNAs complementary to target CBV genes. The dsRNAs are cleaved using Dicer to siRNA pool and introduced to cells by transfection. We produced specific dsRNAs and siRNA pools targeted to 5'UTR, 2A and 3D genes of CVB3 that inhibit completely virus replication in vitro in HEp-2 cells. Cytotoxic effects were not observed in the used concentrations.