title: Transforming growth factor-beta1 downregulation of Smad1 gene expression in rat hepatic stellate cells.
abstract: Smads are intracellular signaling molecules of the transforming growth factor-beta (TGF-beta) superfamily that play an important role in the activation of hepatic stellate cells (HSCs) and hepatic fibrosis. Excepting the regulation of Smad7, receptor-regulated Smad gene expression is still unclear. We employed rat HSCs to investigate the expression and regulation of the Smad1 gene, which is a bone morphogenetic protein (BMP) receptor-regulated Smad. We found that the expression and phosphorylation of Smad1 are increased during the activation of HSCs. Moreover, TGF-beta significantly inhibits Smad1 gene expression in HSCs in a time- and dose-dependent manner. Furthermore, although both TGF-beta1 and BMP2 stimulate the activation of HSCs, they have different effects on HSC proliferation. In conclusion, Smad1 expression and phosphorylation are increased during the activation of HSCs and TGF-beta1 significantly inhibits the expression of the Smad1 gene.
authors.affiliation: Faculty of Pharmacy, University of Manitoba, Winnipeg, MB R3T 2N2 Canada.
authors.forename: Hong
authors.initials: H
authors.lastname: Shen
authors.forename: Guojiang
authors.initials: G
authors.lastname: Huang
authors.forename: Mohammed
authors.initials: M
authors.lastname: Hadi
authors.forename: Patrick
authors.initials: P
authors.lastname: Choy
authors.forename: Manna
authors.initials: M
authors.lastname: Zhang
authors.forename: Gerald Y
authors.initials: GY
authors.lastname: Minuk
authors.forename: Yongping
authors.initials: Y
authors.lastname: Chen
authors.forename: Yuewen
authors.initials: Y
authors.lastname: Gong
mesh_terms: D000818:Animals; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000235:genetics*; D015536:Down-Regulation; D015870:Gene Expression / Q000187:drug effects*; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D051785:Smad Proteins; D051898:Smad1 Protein; D015534:Trans-Activators / Q000235:genetics*; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D053773:Transforming Growth Factor beta1
chemical_list: C525719:Bmp2 protein, mouse; C525720:Bmp2 protein, rat; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D004268:DNA-Binding Proteins; D051785:Smad Proteins; D051898:Smad1 Protein; C497401:Smad1 protein, mouse; C497400:Smad1 protein, rat; C508961:Tgfb1 protein, mouse; C508962:Tgfb1 protein, rat; D015534:Trans-Activators; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1