부산대학교 도서관

Background & Aims Analysis in silico suggests that occludin ( OCLN), a key receptor for HCV, is a candidate target of miR-122; the most abundant hepatic micro RNA. We aimed to determine if miR-122 can decrease HCV entry through binding to the 3′ UTR of OCLN m RNA. Design Huh7.5 cells were cotransfected with luciferase construct containing 3′ UTR of OCLN ( pLuc-OCLN) and with selected miRNAs (0-50 nM) and luciferase activity was measured. Huh7.5 cells were also infected by viral particles containing lenti-miR122 genome or control virus. After 48 h, the cells were infected with HCV pseudo-particles (HCVpp) and VSV pseudo-particles (VSVpp). After 72 h of infection, luciferase activity was measured and HCVpp activity was normalized to VSVpp activity. Results miR-122 binds to the 3′-UTR of OCLN and down-regulates its expression; cotransfection of miR-122 mimic with pLuc-OCLN resulted in a significant decrease in luciferase activity [by 55% ( P < 0.01)], while a non-specific miRNA and a mutant miR-122 did not have any effect. miR-122 mimic significantly down-regulated [by 80% ( P < 0.01)] OCLN protein in Huh7.5 cells. Accordingly, patients with chronic hepatitis C and higher levels of hepatic miR-122 have lower hepatic expression of OCLN. Immuno-fluorescence imaging showed a decrease in colocalization of OCLN and CLDN following miR-122 over-expression in HCV infected cells. Huh7.5 cells transiently expressing Lenti-miR122 system showed 42% ( P < 0.01) decrease in HCV entry. Conclusion This study uncovers a novel antiviral effect of miR-122 on human liver cells and shows that over-expression of miR-122 can decrease HCV entry into hepatocytes through down-regulation of OCLN. [ABSTRACT FROM AUTHOR]