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Gut 61:1600-1609 doi:10.1136/gutjnl-2011-300717
  • Original articles
    • Hepatology

MicroRNA-221/222 upregulation indicates the activation of stellate cells and the progression of liver fibrosis

  1. Norifumi Kawada1,2
  1. 1Department of Hepatology, Graduate School of Medicine, Osaka City University, Osaka, Japan
  2. 2Liver Research Center, Graduate School of Medicine, Osaka City University, Osaka, Japan
  3. 3Center for the Advancement of Higher Education, Faculty of Engineering, Kinki University, Hiroshima, Japan
  4. 4PhoenixBio Co Ltd., Hiroshima, Japan
  5. 5Department of Anatomy and Cell Biology, Graduate School of Medicine, Nagoya City University, Aichi, Japan
  1. Correspondence to Professor Norifumi Kawada, Department of Hepatology, Graduate School of Medicine, Osaka City University, 1-4-3, Asahimachi, Abeno, Osaka 545-8585, Japan; kawadanori{at}med.osaka-cu.ac.jp
  1. Contributors TO, EM, NK: conception, design, analysis and interpretation of data, drafting of the manuscript, critical revision of article, final approval given. HF, YS: analysis and interpretation of data, final approval given. KY, KI: conception, design, drafting of the manuscript, final approval given.

  • Revised 1 December 2011
  • Accepted 15 December 2011
  • Published Online First 20 January 2012

Abstract

Background MicroRNAs (miRNAs) are important in hepatic pathophysiology and the development of liver cancer.

Objective To explore miRNAs that are regulated with the progression of liver fibrosis caused by chronic liver disease.

Design The regulated miRNAs in human livers infected with hepatitis C virus were identified by microarray analysis. Their expression in human livers with non-alcoholic steatohepatitis, mouse livers from two fibrosis models and cultured stellate cells was validated by real-time RT-PCR. The regulation of miR-222 expression in stellate cells by nuclear factor kappa B (NF-κB) was assayed. Finally, the effects of an miR-222 precursor or inhibitor on the expression of cyclin-dependent kinase inhibitor 1B (CDKN1B) and the growth of LX-2 cells were determined.

Results It was found that miR-199a-5p/199a-3p and miR-221/222 were upregulated in the human liver in a fibrosis progression–dependent manner. Among these miRNAs, miR-221/222 were upregulated in LX-2 cells and increased during the course of culture-dependent activation of mouse primary stellate cells, in a manner similar to the expression of α1(I) collagen and α-smooth muscle actin mRNAs. The expression of miR-221/222 increased in mouse models of liver fibrosis. In contrast, an NF-κB inhibitor significantly suppressed the miR-222 induction that was stimulated in culture by transforming growth factor α or tumour necrosis factor α. Although overexpression or downregulation of miR-222 failed to regulate the growth of LX-2 cells, miR-222 bound to the CDKN1B 3′UTR and regulated the expression of the corresponding protein.

Conclusion miR-221/222 may be new markers for stellate cell activation and liver fibrosis progression.

Footnotes

  • Funding NK was supported by a grant-in-aid for scientific research from the Japan Society for the Promotion of Science (JSPS) (No 21390232; 2009–2011), a grant from the Ministry of Health, Labour and Welfare of Japan (2008–2010) and a Thrust Area Research Grant from Osaka City University (2008–2011). TO was supported by a grant-in-aid for scientific research from the JSPS (No 22790666; 2010–2011).

  • Competing interests None.

  • Ethics approval Ethics approval was provided by Osaka City University Medical School.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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