Z Gastroenterol 2009; 47 - P1_28
DOI: 10.1055/s-0029-1191782

The role of microRNA-29 in collagen deposition during liver fibrogenesis

M Kwiecinski 1, I Strack 1, A Noetel 1, M Scheffler 1, U Töx 2, S Schulte 2, U Drebber 1, N Elfimova 1, HP Dienes 1, M Odenthal 1
  • 1Institut für Pathologie, Universität zu Köln
  • 2Abteilung für Gastroenterologie und Hepatologie am Abdominalzentrum, Universität zu Köln

Aims: MicroRNAs (miRNAs) are endogenously expressed regulatory noncoding RNAs, repressing protein translation by binding to their target mRNAs. In the present, study we investigated the role of the members of the miRNA-29 family in regulation of extracellular matrix production during liver fibrogenesis.

Methods: In order to identify miRNA species involved in repression of collagen synthesis, the databases of Miranda, Targetscan and Pictar were screened. MiR-29a and miR-29b were analysed during in vitro induced myofibroblastic differentiation of primary hepatic stellate cells (HSC), in human biopsies of chronically HCV infected liver representing different fibrotic stages (S0-S4), and in experimental rat fibrosis after bile-duct ligation by real time PCR of total RNA extracted by the Trizol method. The 3´-untranslated regions (UTR) of collagens 1A1 and 4A1, or miR-29a /b complementary sequences were fused downstream to the luciferase gene of the psicheck vector providing endogenous normalisation of the luciferase reporter activity. Ago-miR-29, mimicking miR-29, was transfected into HSC and collagen synthesis was determined by Western blot

Results: Searching different databases revealed putative miR-29 target sequences in transcripts of various collagen subunits but also e.g. of fibrillin and identified the members of the miR-29 family as probable regulators of extracellular matrix depositon. Analysis of miR-29a and miR-29b expression in chronically diseased liver demonstrated prominent downregulation of miR-29a and moderate downregulation of miR-29b upon experimental and human liver fibrosis. MiR-29 as repressors of collagen synthesis were proven by reporter assays of chimeric collagen 3´-UTR luciferase fusion constructs and by reduced collagen protein level in HSC overexpressing miR-29 by ago-miR treatment.

Conclusion: Members of miR-29 family, repressed during liver fibrogenesis, are suggested to act as antifibrogenic mediators.

chronic liver disease - experimental fibrosis - extracellular matrix deposition - heptic stellate cells - miRNA