Smad2/3乙酰化/磷酸化对肾脏成纤维细胞细胞外基质合成的调节作用

Backgroud: AngII-Smad2/3 signal passway has long been recognized stimulating extracellular matrix (ECM) synthesis and plays a critical role in the renal fibrosis. The phosphorylationg and nucleus translocation of Smad proteins have been demonstrated to be involved in AngII- induce ECM synthesis. Acetylation was recently noticed as another way of Smads modification. The aim of the study is to investigate whether acetylaiton of Smad2/3 envolved in the progress of AngII-induced ECM synthesis, which is the enzyme, the relationship between acetylaiton and phosphorylationg of Smad2/3 and the related mechanism of them in AngII-induced ECM synthesis. Methodology/Prinicipal Dindings: Cultured rat renal interstitial fibroblast cell line (NRK-49F) was used in the experiment. 1) AngII increased the expressions of ECM proteins, including collagenIV and fibronectin, in a concentration-dependent manner. 2) AngII stimulated acetylation of Smad2/3, which could be inhibited by C646 (p300 inhibitor) and C646 also could decrease AngII-induced synthesis of ECM. 3) Transfection of siRNA-p300, but not siRNA-CBP, blocked AngII-induced acetylation of Smad2/3, and the increases of collagenIV and fibronectin expressions. 4) The inhibitor of p38 (SB203580), neither PD98059 (inhibitor to Erk ) nor SP600125(inhibitor to JNK ), reversed AngII-induced phosphorylation of smad2/3 as well as the expressions of collagenIV and fibronectin. 5) SB203580 abrogated AngII-induced increase of Smad2/3 acetylation, however, neither C646 nor siRNA-p300 had obvious effects on AngII induced increase in Smad2/3 phosphorylation. Conclusions: 1) AngII sitmulates Smad2/3 acetylation by regulating P300 in cultured NRK-49F, which participate in synthesis of ECM. 2) p38 plays the crucial role in Ang II-induced Smad2/3 phosphorylation and production of ECM. 3) In the way of Ang II induced abnormal generation of ECM, phosphorylation lays upstream of acetylaiton of Smad2/3. C646 also could decrease AngII-induced synthesis of ECM. 3) Transfection of siRNA-p300, but not siRNA-CBP, blocked AngII-induced acetylation of Smad2/3, and the increases of collagenIV and fibronectin expressions. 4) The inhibitor of p38 (SB203580), neither PD98059 (inhibitor to Erk ) nor SP600125(inhibitor to JNK ), reversed AngII-induced phosphorylation of smad2/3 as well as the expressions of collagenIV and fibronectin. 5) SB203580 abrogated AngII-induced increase of Smad2/3 acetylation, however, neither C646 nor siRNA-p300 had obvious effects on AngII induced increase in Smad2/3 phosphorylation. Conclusions: 1) AngII sitmulates Smad2/3 acetylation by regulating P300 in cultured NRK-49F, which participate in synthesis of ECM. 2) p38 plays the crucial role in Ang II-induced Smad2/3 phosphorylation and production of ECM. 3) In the way of Ang II induced abnormal generation of ECM, phosphorylation lays upstream of acetylaiton of Smad2/3.