Figure 2

RO8191 activates JAK/STAT and induces IFN-like signals.

(a) The cytopathic effect of EMCV infection was inhibited by the indicated concentrations of RO8191 or IFN-α. Viable cells were stained with crystal violet. The data shown are the mean values and SDs based on experiments performed in quadruplicate. (b) ISG expression levels were measured using real-time RT-PCR. Total RNA was extracted from HCV replicon cells cultured in the presence of 50 μM RO8191 or 100 IU/mL IFN-α for 2 or 8 h and known ISGs were analyzed. Asterisk indicates 2-h treatment with agents. The values shown are the mean fold change induction compared to the mRNA level of human β-actin and the fold change induction compared to untreated cells. (c) HCV replicon cells were treated with various concentrations of the indicated agents for 15 min. Total lysates were immunoblotted with antibodies to STATs or JAK kinases. The HCV replicon IC₅₀ of IFN-α was 0.4 IU/mL, that of IFN-β was 3 IU/mL and that of IFN-γ was 0.3 ng/mL.