Hes1, an important gene for activation of hepatic stellate cells, is regulated by Notch1 and TGF-β/BMP signaling

World J Gastroenterol. 2015 Jan 21;21(3):878-87. doi: 10.3748/wjg.v21.i3.878.

Abstract

Aim: To determine the role of Notch1 and Hes1 in regulating the activation of hepatic stellate cells (HSCs) and whether Hes1 is regulated by transforming growth factor (TGF)/bone morphogenetic protein (BMP) signaling.

Methods: Immunofluorescence staining was used to detect the expression of desmin, glial fibrillary acidic protein and the myofibroblastic marker α-smooth muscle actin (α-SMA) after freshly isolated, normal rat HSCs had been activated in culture for different numbers of days (0, 1, 3, 7 and 10 d). The expression of α-SMA, collagen1α2 (COL1α2), Notch receptors (Notch1-4), and the Notch target genes Hes1 and Hey1 were analyzed by reverse transcriptase-polymerase chain reaction. Luciferase reporter assays and Western blot were used to study the regulation of α-SMA, COL1α1, COL1α2 and Hes1 by NICD1, Hes1, CA-ALK3, and CA-ALK5 in HSC-T6 cells. Moreover, the effects of inhibiting Hes1 function in HSC-T6 cells using a Hes1 decoy were also investigated.

Results: The expression of Notch1 and Hes1 mRNAs was significantly down-regulated during the culture of freshly isolated HSCs. In HSC-T6 cells, Notch1 inhibited the promoter activities of α-SMA, COL1α1 and COL1α2. On the other hand, Hes1 enhanced the promoter activities of α-SMA and COL1α2, and this effect could be blocked by inhibiting Hes1 function with a Hes1 decoy. Furthermore, co-transfection of pcDNA3-CA-ALK3 (BMP signaling activin receptor-like kinase 3) and pcDNA3.1-NICD1 further increased the expression of Hes1 compared with transfection of either vector alone in HSC-T6 cells, while pcDNA3-CA-ALK5 (TGF-β signaling activin receptor-like kinase 5) reduced the effect of NICD1 on Hes1 expression.

Conclusion: Selective interruption of Hes1 or maintenance of Hes1 at a reasonable level decreases the promoter activities of α-SMA and COL1α2, and these conditions may provide an anti-fibrotic strategy against hepatic fibrosis.

Keywords: Hepatic fibrosis; Hepatic stellate cells; Hes1; Notch1; TGF-β/BMP.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / genetics
  • Actins / metabolism
  • Animals
  • Basic Helix-Loop-Helix Transcription Factors / genetics
  • Basic Helix-Loop-Helix Transcription Factors / metabolism*
  • Biomarkers / metabolism
  • Bone Morphogenetic Protein Receptors, Type I / genetics
  • Bone Morphogenetic Protein Receptors, Type I / metabolism
  • Bone Morphogenetic Proteins / metabolism*
  • Cells, Cultured
  • Collagen Type I / genetics
  • Collagen Type I / metabolism
  • Gene Expression Regulation
  • Genes, Reporter
  • Hepatic Stellate Cells / metabolism*
  • Hepatic Stellate Cells / pathology
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / metabolism*
  • Liver Cirrhosis / genetics
  • Liver Cirrhosis / metabolism*
  • Liver Cirrhosis / pathology
  • Myofibroblasts / metabolism
  • Myofibroblasts / pathology
  • Protein Serine-Threonine Kinases / genetics
  • Protein Serine-Threonine Kinases / metabolism
  • RNA, Messenger / metabolism
  • Rats
  • Receptor, Notch1 / genetics
  • Receptor, Notch1 / metabolism*
  • Receptor, Transforming Growth Factor-beta Type I
  • Receptors, Transforming Growth Factor beta / genetics
  • Receptors, Transforming Growth Factor beta / metabolism
  • Signal Transduction*
  • Time Factors
  • Transcription Factor HES-1
  • Transfection
  • Transforming Growth Factor beta / metabolism*

Substances

  • Actins
  • Basic Helix-Loop-Helix Transcription Factors
  • Biomarkers
  • Bone Morphogenetic Proteins
  • Collagen Type I
  • Hes1 protein, rat
  • Homeodomain Proteins
  • Notch1 protein, rat
  • RNA, Messenger
  • Receptor, Notch1
  • Receptors, Transforming Growth Factor beta
  • Transcription Factor HES-1
  • Transforming Growth Factor beta
  • smooth muscle actin, rat
  • Protein Serine-Threonine Kinases
  • Bone Morphogenetic Protein Receptors, Type I
  • Receptor, Transforming Growth Factor-beta Type I
  • Tgfbr1 protein, rat