Alcohol Facilitates HCV RNA Replication Via Up-Regulation of mi R-122 Expression and Inhibition of Cyclin G1 in Human Hepatoma Cells.

Background Clinical studies demonstrate synergistic liver damage by alcohol and hepatitis C virus ( HCV); however, the mechanisms by which alcohol promotes HCV infection remain obscure. The liver-specific micro RNA-122 (miR-122) regulates HCV replication and expression of host genes, including Cyclin G1. Here, we hypothesized that alcohol regulates mi R-122 expression and thereby modulates HCV RNA replication. Methods The J6/ JFH/ Huh-7.5 model of HCV infection was used in this study. Real-time quantitative polymerase chain reaction, Western blotting, electrophoretic mobility shift assay, and confocal microscopy were used for experimental analysis. Results We found that acute alcohol exposure (25 mM) significantly increased intracellular HCV RNA as well as mi R-122 levels in Huh-7.5 and Huh-7.5/ CYP2 E1 expressing cells in the presence and absence of J6/ JFH- HCV infection. Expression of the mi R-122 target, Cyclin G1, was inhibited by alcohol both in J6/ JFH-infected and uninfected Huh-7.5 cells. The use of a mi R-122 inhibitor increased Cyclin G1 expression and prevented the alcohol-induced increase in HCV RNA and protein levels, suggesting a mechanistic role for alcohol-induced mi R122 in HCV replication. We discovered that si RNA-mediated silencing of Cyclin G1 significantly increased intracellular HCV RNA levels compared with controls, suggesting a mechanistic role for Cyclin G1 in HCV replication. Alcohol-induced increase in mi R-122 was associated with increased nuclear translocation and DNA binding of the nuclear regulatory factor-κ B and could be prevented by NF-κ B inhibition. Conclusions Our novel data indicate a mi R-122-mediated mechanism for alcohol increasing HCV RNA replication. We show for the first time that Cyclin G1, a mi R-122 target gene, has regulatory effects on HCV replication and that alcohol increases HCV replication by regulating mi R-122 and Cyclin G1. [ABSTRACT FROM AUTHOR]