PPARγ配体抑制气道肌纤维母细胞分化的作用机制

Mechanism of Inhibiting Bronchial Myofibroblast Differentiation by PPARγ Ligand

目的探讨过氧化物酶体增殖物激活受体(PPARγ)配体对气道肌纤维母细胞分化和转化生长因子β(1TGF-β1)/Smad3信号传导途径的影响。方法小鼠气道纤维母细胞原代培养,并于特定时间加入TGF-β(15mg/L)或PPARγ配体-罗格列酮(10mmol/L)或PPARγ抑制剂(10mmol/L)处理后,用Westernblot检测肌纤维母细胞的标志物-α平滑肌肌动蛋白原(αSMA)以及结缔组织基质-纤维结合蛋白和I型胶原蛋白的表达情况;并采用Westernblot、DNA凝胶电泳迁移率检测和免疫细胞化学检测对Smad3蛋白的磷酸化、与DNA结合能力和细胞核转位的影响。结果罗格列酮能抑制TGF-β1诱导的αSMA的产生,并降低纤维结合蛋白和I型胶原蛋白的表达;同时抑制Smad3的磷酸化、与DNA的结合能力和细胞核转位。PPARγ配体的抑制剂能够完全消除PPARγ配体对TGF-β1的抑制作用。结论 PPARγ配体能够通过阻断TGF-β1/Smad3信号传导通路,抑制TGF-β1诱导产生的肌纤维母细胞分化和纤维化的细胞效应。

Objective To investigate the effect of PPARγ ligand on bronchial myofibroblast differentiation and transforming growth factor-β1（TGF-β1）/Smad3 signal pathway.Methods Primary culture of bronchial myofibroblasts from mice was performed for in vitro study.After treated with TGF-β1（5 mg/L）,PPARγ ligand（rosiglitizone,10 mmol/L）,or PPARγ inhibitor（10 mmol/L）at specific time points,the expressions of α-smooth muscle actin（α-SMA）,a marker of myofibroblast differentiation,fibronectin in connective tissue matrix,and type Ⅰ collagen were detected by Western blot.The effects of PPARγ on the phosphorylation,DNA binding,and nuclear translocation of Smad3 were determined by Western blot,DNA electrophoretic mobility gel shift assay,and immunocytochemistry.Results Rosiglitizone inhibited the production of α-SMA induced by TGF-β1 and decreased the expressions of fibronectin and type Ⅰ collagen.Rosiglitizone also inhibited the phosphorylation,DNA binding,and nuclear translocation of Smad3.The inhibitor of PPARγ completely abrogated these inhibitory effects of PPARγ ligand on TGF-β1.Conclusion PPARγ ligand could inhibit the myofibroblast differentiation and tissue remodeling induced by TGF-β1 through blocking TGF-β1/Smad3 signal pathway.