Figure 5. Silencing efficacy of siRNA formulated in optimized MEND against ongoing infectious HCV RNA.

(a) Schedule of treatment by dh-siRNA formulated in optimized MENDs in chimeric mice carrying human hepatocytes (PXB mice) infected with HCV genotype 1b (HCR6). The mice were administered intravenously with siRNA (1 mg/kg)-loaded optimized MENDs by 2 repeat doses. (b) Long-term silencing efficacy of siHCVs (the HCV-specific dh-siRNAs formulated in optimized MEND) against ongoing infectious HCV RNA. The HCV genomic RNA change from baseline in individual mice following treatment with siHCVs (n = 3) or with siControl (n = 3) were monitored for 2 weeks. (c) The serum human albumin levels (indicated as bar in left y-axis) in individual animals, as well as the change of body weight (indicated as line in right y-axis; plotted as mean + s.d. (across 3 animals)) over 2 weeks. (d) Intrahepatic analysis of chimeric mice infected with HCV. Two weeks after administration of siHCVs or siControl (injected on day 0 and day 3), chimeric mouse liver was harvested. The presence of human hepatocytes and HCV core protein were evaluated by immunohistochemistry. (e) dh-siRNA-mediated amelioration of HCV-induced liver damage in a murine model of inducible HCV. The inducible-HCV transgenic mouse model (HCV-Tg mice; see Materials and Methods) provides conditional expression of HCV core, E1, E2, and NS2 proteins. Six months after HCV induction, mice were treated by injection (on days 0 and 2) with optimized MENDs loaded with a single species of dh-siRNA (si197-1). On day 4, livers were harvested and assessed histologically (hematoxylin and eosin staining) for HCV-induced liver inflammatory responses. Degenerated liver tissue with diffuse inflammation and spotty necrosis was observed in the livers of the “no treatment” and siControl mice; treatment with si197-1-loaded optimized MENDs reduced HCV-induced liver damage. Arrows indicate necrosis; arrowheads indicate inflammation.