Document Type



Medicine and Health Sciences


Background & Aims Heme oxygenase-1 (HO-1) is an antioxidant defense and key cytoprotective enzyme, which is repressed by Bach1. MicroRNA-122 (miR-122) is specifically expressed and highly abundant in human liver and required for replication of hepatitis C virus (HCV) RNA. This study was to assess whether a specific miR-122 antagomir down-regulates HCV protein replication and up-regulates HO-1. Methods We transfected antagomir of miR-122, 2′-O-methyl-mimic miR-122, or non-specific-control antagomir (NSCA) into wild type Huh-7 cells or Huh-7 stably replicating HCV subgenomic core-NS3 (CNS3 replicon cells), or NS3-5B (9–13 replicon cells). Results Antagomir of miR-122 reduced the abundance of HCV-RNA by 64% in CNS3, and by 84% in 9–13 cells. In contrast, transfection with 2′-O-methlyl-mimic miR-122 increased HCV levels up to 2.5-fold; transfection with NSCA did not change the level of HCV. Antagomir of miR-122 also decreased Bach1 and increased HO-1 mRNA levels in CNS3, 9–13, and WT Huh-7 cells. Increasing HO-1 by silencing Bach1 with 50 nM Bach1-siRNA or by treatment with 5 μM cobalt protoporphyrin or heme (known inducers of HO-1) decreased HCV RNA and protein by 50% in HCV replicon cells. Conclusions Down-regulation of HCV replication using an antagomir targeted to miR-122 is effective, specific, and selective. Increasing HO-1, by silencing the Bach1 gene or by treatment with cobalt protoporphyrin or heme, decreases HCV replication. Thus, miR-122 plays an important role in the regulation of HCV replication and HO-1/Bach1 expression in hepatocytes. Down-regulation of miR-122 and up-regulation of HO-1 may be new strategies for anti-HCV intervention and cytoprotection.


Gastroenterology. Author manuscript; available in PMC 2008 October 1. Published in final edited form as: Gastroenterology. 2007 October; 133(4): 1166–1174. Published online 2007 August 3. doi: 10.1053/j.gastro.2007.08.002 PMCID: PMC2128739 NIHMSID: NIHMS32086