p-CREB-1 promotes hepatic fibrosis through the transactivation of transforming growth factor-β1 expression in rats

Int J Mol Med. 2016 Aug;38(2):521-8. doi: 10.3892/ijmm.2016.2630. Epub 2016 Jun 8.

Abstract

Phosphorylated cAMP-responsive element binding protein-1 (p-CREB-1) is an important transcription factor which has been reported to be implicated in fibrogenesis. However, the association between p-CREB-1 and transforming growth factor-β1 (TGF-β1)-mediated liver fibrogenesis remains poorly understood. In the present study, exogenous TGF-β1 recombinant protein was used to activate hepatic stellate cells (HSCs), and we established a rat model of tetrachloromethane (CCl4)‑induced liver fibrosis. Loss- and gain-of-function studies were performed to examine the role of p-CREB-1 in liver fibrogenesis, and the detailed mechanism responsible for these effects was further explored using chromatin immunoprecipitation and luciferase reporter gene assays. We found that p-CREB-1 expression was significantly upregulated in a rat model of hepatic fibrosis. We also demonstrated that p-CREB-1 increased TGF-β1 expression and auto‑induction in HSCs, through directly binding to the CRE site within the TGF-β1 promoter in order to enhance its transcriptional activity. Moreover, lentivirus-mediated CREB-1 overexpression promoted hepatic fibrogenesis in rats. These findings suggest that p-CREB-1 may function as a potent profibrogenic factor through the transactivation of TGF-β1 expression in liver fibrosis.

MeSH terms

  • Animals
  • Cell Line
  • Cyclic AMP Response Element-Binding Protein / metabolism*
  • Hepatic Stellate Cells / drug effects
  • Hepatic Stellate Cells / metabolism
  • Humans
  • Liver Cirrhosis / genetics*
  • Liver Cirrhosis / metabolism
  • Male
  • Phosphorylation / drug effects
  • Promoter Regions, Genetic / genetics*
  • Protein Binding / drug effects
  • Rats, Sprague-Dawley
  • Transcriptional Activation / drug effects
  • Transcriptional Activation / genetics*
  • Transforming Growth Factor beta1 / genetics*
  • Transforming Growth Factor beta1 / metabolism
  • Transforming Growth Factor beta1 / pharmacology
  • Up-Regulation / drug effects
  • Up-Regulation / genetics

Substances

  • Cyclic AMP Response Element-Binding Protein
  • Transforming Growth Factor beta1