Transforming growth factor β1 represses proximal tubular cell microRNA-192 expression through decreased hepatocyte nuclear factor DNA binding

Biochem J. 2012 Apr 15;443(2):407-16. doi: 10.1042/BJ20111861.

Abstract

miR (microRNA)-192 plays key roles in renal pathological and physiological responses, by repressing targets including Zeb1, Zeb2 and Wnk1. In the present study, we have assessed the regulation of miR-192 expression. We found that TGF-β1 (transforming growth factor β1) down-regulates miR-192 and miR-194, co-transcribed in the shared precursor pri-miR (primary miR transcript)-192/194. Luciferase reporter analysis showed constitutive promoter activity within nucleotides +21 to -223. We identified HNF (hepatocyte nuclear factor) and p53 binding sites within this region that were required for constitutive promoter activity, which was decreased by TGF-β1 through an Alk5-dependent mechanism. TGF-β1 treatment decreased HNF binding to the miR-194-2/192 promoter, whereas knockdown of HNF-1 inhibited mature miR-192 and miR-194 expression. miR-192, miR-194 and HNF expression were restricted to a defined subset of human tissues including kidney, small intestine, colon and liver. Our results from the present study identify co-ordinated regulation of miR-192 and miR-194, with binding of HNF and p53 transcription factors necessary for activation of transcription, and TGF-β1-mediated repression through decreased HNF binding to its cognate promoter element.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Cells, Cultured
  • DNA / genetics
  • DNA / metabolism*
  • Down-Regulation*
  • Hepatocyte Nuclear Factors / genetics
  • Hepatocyte Nuclear Factors / metabolism*
  • Humans
  • MicroRNAs / genetics*
  • Promoter Regions, Genetic
  • Protein Binding
  • RNA, Small Interfering / genetics
  • Transforming Growth Factor beta1 / genetics
  • Transforming Growth Factor beta1 / metabolism*
  • Tumor Suppressor Protein p53 / genetics
  • Tumor Suppressor Protein p53 / metabolism

Substances

  • Hepatocyte Nuclear Factors
  • MIRN192 microRNA, human
  • MicroRNAs
  • RNA, Small Interfering
  • TGFB1 protein, human
  • TP53 protein, human
  • Transforming Growth Factor beta1
  • Tumor Suppressor Protein p53
  • DNA