Silencing HCV Replication in Its Reservoir

Abstract

BACKGROUND: HCV infection and its complications are among the leading public health challenges; the emergence of drug-resistant variants are expected to be a major problem. A novel combinatorial small interfering RNA (siRNA) could be a novel triple therapy that could be suitable for genotype 4. Although HCV is a hepatotropic virus, there is reliable evidence about its replication in peripheral blood mononuclear cells (PBMC) of chronically infected patients; these cells act as an extra-hepatic reservoir for viral recurrence and persistence. The patients with HCV-RNA in PBMC showed a significantly lower response to therapy that supports to be one of the factors influencing therapeutic response. Almost all regions of HCV show potential for siRNA target with relative efficiencies of individual siRNA sequences.

AIM: This study aims to test the efficacy of siRNA against HCV-4 replication in PBMC in vitro, to introduce an alternative therapeutic option for HCV-4 suitable to eradicate it from both hepatic and extra-hepatic reservoirs.

METHODS: Efficacy of synthesised siRNA molecule that targets 5^/UTR of domain IIIC within IRES of HCV RNA to eradicate HCV intra-PBMC in vitro was tested and compared with IFN/RBV in vitro, by using both qRT-PCR and western blot. Sixty genotype-4 chronic HCV patients who are naïve for any HCV treatment were enrolled and tested for the presence of HCV intra-PBMC using qRT-PCR before and after siRNA treatment in vitro.

RESULTS: Real-time PCR analysis showed a significant reduction of HCV RNA levels after 24hr post-HCV-positive-PBMCs treatment by siRNA with cell vitality reached up to 98%. Besides a complete inhibition of NS5A viral protein expression, that is functionally essential for viral assembly, replication and egress.

CONCLUSION: So, Targeting HCV infection using RNA interference technology might be a reliable therapeutic option for chronic HCV patients with HCV minus strand within PBMCs.