MiR-214 Promotes the Alcohol-Induced Oxidative Stress via Down-Regulation of Glutathione Reductase and Cytochrome P450 Oxidoreductase in Liver Cells.

Background The involvement of oxidative stress in the pathophysiological process of alcohol-induced liver injury has been studied for decades. However, the role of micro RNAs (mi RNAs) targeting to oxidative stress genes in the pathogenesis of alcohol-induced liver injury has not yet been determined. The aim of this study was to identify the targeting of miR-214 to both glutathione reductase ( GSR) and cytochrome P450 oxidoreductase ( POR) genes and elucidate their impact on alcohol-induced oxidative stress in liver cells. Methods The miR-214 expression vector and reporter vectors of GSR and POR 3′- UTR were constructed. Human hepatoma cell (Bel7402), human embryonic kidney 293 cell ( HEK293), and rat normal hepatocyte ( BRL) were transfected and stimulated with ethanol (EtOH). Wistar rats were fed with EtOH for 4 weeks. The GSR and POR protein levels were detected by Western blot, and their activities were measured using the spectrophotometric method. The miR-214 expression was detected by real-time PCR. The index of oxidative stress including the total antioxidant capacity (T- AOC) and malondialdehyde ( MDA) level was detected by commercial kits. Results miR-214 bound specifically to the GSR and POR 3′- UTR and repressed the expressions and activities of both GSR and POR. EtOH up-regulated the miR-214 expression, down-regulated the GSR and POR protein levels and activities, and induced the oxidative stress in human and rat liver cells. EtOH-fed Wistar rats further confirmed that alcohol up-regulates the miR-214 expression in liver and repressed both GSR and POR in vivo. Conclusions These findings demonstrated a new mechanism by which the alcohol repressed the GSR and POR expression via up-regulation of miR-214 and in turn induced oxidative stress in liver cells. [ABSTRACT FROM AUTHOR]