蓝萼甲素下调GSK3β/β-catenin信号通路抑制TGF-β1诱导的肺成纤维细胞转化

Glaucocalyxin A represses TGF-β1-induced lung fibroblast differentiation by down-regulation of GSK3β/β-catenin signaling

本研究探讨了蓝萼甲素抑制转化生长因子-β1 (transforming growth factor-β1, TGF-β1)诱导的肺成纤维细胞向肺肌成纤维细胞转化的作用及其分子机制。应用Western blot法、细胞免疫荧光法、胶原胶收缩法等检测蓝萼甲素抑制TGF-β1诱导的肺成纤维细胞转化指标的变化情况;应用Western blot法、质粒转染法、激活剂等考察蓝萼甲素对TGF-β1诱导的肺成纤维细胞转化中Smad3、细胞外信号调节激酶(extracellular regulated protein kinases,ERK)、糖原合成酶激酶3β(glycogen synthase kinase 3β, GSK3β)(Ser9)三者的磷酸化水平与β-连环蛋白(β-catenin)表达情况及其调控作用。结果表明:蓝萼甲素能够显著降低肺成纤维细胞转化中α-平滑肌肌动蛋白(α-smooth muscle actin,α-SMA)表达水平;明显减少细胞肌丝的形成以及肺成纤维细胞胶原胶的收缩能力;显著下调纤维黏连蛋白(fibronectin, FN)的生成;不影响Smad3及ERK1/2的磷酸化水平;显著下调GSK3β(Ser9)的磷酸化及β-catenin的表达水平;GSK3β(S9A)突变体能明显抑制肺成纤维细胞转化;β-catenin激活剂SKL2001可部分逆转蓝萼甲素抑制肺成纤维细胞转化的作用。上述结果提示,蓝萼甲素能显著抑制肺成纤维细胞转化,这与蓝萼甲素下调GSK3β/β-catenin信号通路相关。

In this study, we investigated the effect and mechanism of glaucocalyxin A on transforming growth factor-β1(TGF-β1)-induced differentiation of lung fibroblasts by Western blotting, cellular immunofluorescence and collagen gel contraction assays. We monitored the phosphorylation of Smad3, measured extracellular regulated protein kinases(ERK) 1/2 and glycogen synthase kinse3β(Ser9) activity and the level of β-catenin to elucidate the role of glaucocalyxin A. The results show that glaucocalyxin A significantly decreased the expression of α-smooth muscle actin in lung fibroblasts;glaucocalyxin A remarkably reduced the formation of filaments and collagen gel contraction of lung fibroblasts;glaucocalyxin A notably down-regulated the production of fibronectin;glaucocalyxin A did not affect the phosphorylation level of Smad3 and ERK1/2;glaucocalyxin A markedly inhibited the phosphorylation of GSK3 β(Ser9) and the levels of β-catenin;a GSK3 β(S9 A) mutant significantly inhibited lung fibroblast differentiation;and SKL2001, a β-catenin activator, partly reversed the inhibition of lung fibroblast differentiation by glaucocalyxin A. These results suggest that glaucocalyxin A significantly inhibits the differentiation of lung fibroblasts, which is related to the down-regulation of GSK3β/β-catenin signaling.