(A) Intracellular miRNAs were extracted after Huh 7.5.1 cells infected HCV with 0.1 MOI 4 days. (B) Huh 7.5.1 cells were infected with HCV at 0.1 MOI. After 3 days, the culture medium was replaced with exosome-depleted FBS medium. After 24 h, exosomes were isolated from cell supernatants and used for miRNA extraction. (C) Primary human hepatocytes were exposed healthy or HCV-infected patient sera. After 12 days, intracellular miRNAs were extracted, and (D) exosomes were isolated from cell supernatants and used for miRNA extraction. Intracellular miRNAs and extracellular exosomal miRNAs were extracted using a miRNeasy mini kit, and miRNAs expression was analyzed by real-time PCR. U18 was used as an endogenous control in cells for normalization, and Caenorhabditis elegans miR-39 was used as an exogenous control for normalization in the exosomes. Data are expressed as mean ± SD (n=3). *P < 0.05, ** P < 0.01 and *** P < 0.001 were considered statistically significant, as assessed using an unpaired student t-test.