Reciprocal effects of micro-RNA-122 on expression of heme oxygenase-1 and hepatitis C virus genes in human hepatocytes

Gastroenterology. 2007 Oct;133(4):1166-74. doi: 10.1053/j.gastro.2007.08.002. Epub 2007 Aug 3.

Abstract

Background & aims: Heme oxygenase-1 (HO-1) is an antioxidant defense and key cytoprotective enzyme, which is repressed by Bach1. Micro-RNA-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 nonspecific control antagomir, into wild-type (WT) Huh-7 cells or Huh-7 stably replicating HCV subgenomic protein core through nonstructural protein 3 of HCV (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. Transfection with 2'-O-methlyl-mimic miR-122 increased HCV levels up to 2.5-fold. 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 nmol/L Bach1-short interfering RNA or by treatment with 5 mumol/L 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.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Antagomirs
  • Basic-Leucine Zipper Transcription Factors / genetics
  • Basic-Leucine Zipper Transcription Factors / metabolism
  • Cell Line, Tumor
  • Enzyme Induction
  • Fanconi Anemia Complementation Group Proteins / genetics
  • Fanconi Anemia Complementation Group Proteins / metabolism
  • Gene Expression Regulation, Viral* / drug effects
  • Heme / pharmacology
  • Heme Oxygenase-1 / biosynthesis
  • Heme Oxygenase-1 / metabolism*
  • Hepacivirus / drug effects
  • Hepacivirus / genetics
  • Hepacivirus / metabolism*
  • Hepatocytes / drug effects
  • Hepatocytes / enzymology
  • Hepatocytes / metabolism*
  • Hepatocytes / virology
  • Humans
  • MicroRNAs / metabolism*
  • Oligonucleotides / metabolism
  • Protoporphyrins / pharmacology
  • RNA Interference
  • RNA, Messenger / metabolism
  • RNA, Small Interfering / metabolism
  • RNA, Viral / metabolism
  • Transfection
  • Viral Nonstructural Proteins / genetics
  • Viral Nonstructural Proteins / metabolism*
  • Virus Replication

Substances

  • Antagomirs
  • BACH1 protein, human
  • Basic-Leucine Zipper Transcription Factors
  • Fanconi Anemia Complementation Group Proteins
  • MicroRNAs
  • NS3 protein, hepatitis C virus
  • Oligonucleotides
  • Protoporphyrins
  • RNA, Messenger
  • RNA, Small Interfering
  • RNA, Viral
  • Viral Nonstructural Proteins
  • antagomir-122
  • Heme
  • cobaltiprotoporphyrin
  • HMOX1 protein, human
  • Heme Oxygenase-1