
Hepatitis C virus (HCV) directly induces oxidative stress and liver injury. Bach1, a basic leucine zipper mammalian transcriptional repressor, negatively regulates heme oxygenase 1 (HMOX1), a key cytoprotective enzyme that has antioxidant and anti-inflammatory activities. microRNAs (miRNAs) are small noncoding RNAs (≈22 nt) that are important regulators of gene expression. Whether and how miRNAs regulate Bach1 or HCV are largely unknown. The aims of this study were to determine whether miR-196 regulates Bach1, HMOX1, and/or HCV gene expression. HCV replicon cell lines (Con1 and 9–13) of the Con1 isolate and J6/JFH1-based HCV cell culture system were used in this study. The effects of miR-196 mimic on Bach1, HMOX1, and HCV RNA, and protein levels were measured by way of quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting, respectively. The Dual Glo Luciferase Assay System was used to determine reporter activities. miR-196 mimic significantly down-regulated Bach1 and up-regulated HMOX1 gene expression and inhibited HCV expression. Dual luciferase reporter assays demonstrated that transfection of miR-196 mimic resulted in a significant decrease in Bach1 3′-untranslated region (UTR)–dependent luciferase activity but not in mutant Bach1 3′-UTR–dependent luciferase activity. Moreover, there was no detectable effect of mutant miR-196 on Bach1 3′-UTR–dependent luciferase activity. Conclusion: miR-196 directly acts on the 3′-UTR of Bach1 messenger RNA and translationally represses the expression of this protein, and up-regulates HMOX1. miR-196 also inhibits HCV expression in HCV replicon cell lines (genotype 1b) and in J6/JFH1 (genotype 2a) HCV cell culture system. Thus, miR-196 plays a role in both HMOX1/Bach1 expression and the regulation of HCV expression in human hepatocytes. Overexpression of miR-196 holds promise as a potential novel strategy to prevent or ameliorate hepatitis C infection, and to protect against liver injury in chronic HCV infection. (Hepatology 2010.)
Carcinoma, Hepatocellular, Base Sequence, Liver Neoplasms, Molecular Sequence Data, Down-Regulation, Hepacivirus, Transfection, Fanconi Anemia Complementation Group Proteins, Up-Regulation, MicroRNAs, Viral Proteins, Basic-Leucine Zipper Transcription Factors, Humans, RNA, Viral, RNA, Messenger, 3' Untranslated Regions, Heme Oxygenase-1
Carcinoma, Hepatocellular, Base Sequence, Liver Neoplasms, Molecular Sequence Data, Down-Regulation, Hepacivirus, Transfection, Fanconi Anemia Complementation Group Proteins, Up-Regulation, MicroRNAs, Viral Proteins, Basic-Leucine Zipper Transcription Factors, Humans, RNA, Viral, RNA, Messenger, 3' Untranslated Regions, Heme Oxygenase-1
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