title: MicroRNA-221/222 upregulation indicates the activation of stellate cells and the progression of liver fibrosis.
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.
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  miR-221/222 may be new markers for stellate cell activation and liver fibrosis progression.
authors.affiliation: Department of Hepatology, Graduate School of Medicine, Osaka City University, 1-4-3 Asahimachi, Abeno, Osaka, Japan. kawadanori@med.osaka-cu.ac.jp
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Ogawa
authors.forename: Masaru
authors.initials: M
authors.lastname: Enomoto
authors.forename: Hideki
authors.initials: H
authors.lastname: Fujii
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Sekiya
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Yoshizato
authors.forename: Kazuo
authors.initials: K
authors.lastname: Ikeda
authors.forename: Norifumi
authors.initials: N
authors.lastname: Kawada
mesh_terms: D000368:Aged; D000818:Animals; D001707:Biopsy, Needle; D016022:Case-Control Studies; D049109:Cell Proliferation; D002478:Cells, Cultured; D004195:Disease Models, Animal; D018450:Disease Progression; D005260:Female; D005786:Gene Expression Regulation; D005819:Genetic Markers; D055166:Hepatic Stellate Cells / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D008103:Liver Cirrhosis / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000378:metabolism*; D008875:Middle Aged; D011897:Random Allocation; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods; D018709:Statistics, Nonparametric; D046888:Tissue Array Analysis; D015854:Up-Regulation
chemical_list: D005819:Genetic Markers; D035683:MicroRNAs; C525709:MIR221, human; C546122:MIRN221 microRNA, mouse; C525710:MIR222, human; C546123:MIRN222 microRNA, mouse