微小RNA-21-5p靶向Smad7调控转化生长因子-β1诱导心肌纤维化促进房颤的发生

目的探讨微小RNA(miR)-21-5p对转化生长因子(TGF)-β1,诱导心肌纤维化从而促进房颤的影响。方法采用实时定量聚合酶链反应(RT-qPCR)和蛋白质印迹法(Western blot)检测房颤患者(AF组)和窦性心律患者(SR组)右心耳肌组织miR-21-5p、Smad7、TGF-Bi和纤粘蛋白(Fibronecin)的表达。采用RT-qPCR和Westernblot检测过表达miR-21-5p和敲减Smad7对SD乳鼠心肌成纤维细胞TGF-β1,和Fibronecin表达的影响。釆用双荧光素酶报告基因实验验证miR-21-5p和Smad7的靶向关系。结果AF组miR-21-5p、TGF-β1 mRNA及蛋白、Fibronecin蛋白表达水平均高于SR组,Smad7 mRNA和蛋白表达水平均低于SR组(P<0.05).miR-21-5p mimics组miR-21-5p和TGF-β1、Fibronecin mRNA及蛋白表达水平均高于miR-NC组(P<0.05)。si-Smad7组TGF-Rix Fibronecin mRNA及蛋白表达水平均高于si-NC组(P<0.05)omiR-21-5pmimics与Smad73'-UTR野生型质粒共转染后SD乳鼠心肌成纤维细胞荧光素酶活性明显降低(P<0.05)。miR-21-5p mimics组Smad7 mRNA和蛋白表达水平均低于miR-NC组,TGF-β1、Fibronecin mRNA及蛋白表达水平均高于miR-NC组(P<0.05);miR-21-5pmimics+pcDNA3.1-Smad7组TGF-β1、Fibronecin mRNA及蛋白表达水平均低于miR-21-5pmimics+pcDNA3.1组(PvO.05)。结论miR-21-5p表达上调能够通过靶向抑制Smad7促进TGF-β1和Fibronecin分泌,诱导心肌纤维化。

MicroRNA-21-5p regulates transforming growth factor-induced myocardial fibrosis by targeting smad7 and promotes atrial fibrillation

Objective To investigate the effect of microRNA(miRNA)-21-5p on myocardial fibrosis induced by transforming growth factor(TGF)-β1 and to promote atrial fibrillation.Methods The expression levels of miR-21-5p,Smad7,TGF-p,and Fibronecin in right atrial appendages of patients in atrial fibrillation(AF group)and sinus rhythm(SR group)were detected by real time quantitative polymerase chain reaction(RT-qPCR)and Western blotting.Effects of overexpression of miR-21-5p and knockdown of Smad7 on expression of TGF-β1 and Fibronecin in SD neonatal rat cardiac fibroblasts were detected by RT-qPCR and Western blotting.Dual-luciferase assay were used to confirm the target relationship between miR-21-5p and Smad7.Results Expression levels of miR-21丒5p,TGF-Ri mRNA and protein and Fibronecin protein in AF group were higher than those in SR group,expression levels of Smad7 mRNA and protein levels were lower than those in SR group(P<0.05).Expression levels of miR-21-5p,TGF-β1,Fibronecin mRNA and protein in miR-21-5p mimics group were higher than those in miR-NC group(P<0.05).Expression levels of TGF-β1,Fibronecin mRNA and protein in si-Smad7 group were higher than those in si-NC group(P<0.05).Luciferase activity of myocardium fibroblasts in SD neonatal rats decreased significantly after co-transfection of miR-21-5p mimics with Smad7 3'-UTR wild-type plasmid(P<0.05).Expression levels of Smad7 mRNA and protein in miR-21-5p mimics group were lower than those in miR-NC group,expression levels of TGF-Pj,Fibronecin mRNA and protein were higher than those in miR-NC group(P<0.05).Expression levels of TGF-β1,Fibronecin mRNA and protein in miR-21-5p mimics+pcDNA3.1-Smad7 group were lower than those in miR-21-5p mimics+pcDNA3.1 group(P<0.05).Conclusion Upregulation of miR-21-5 p can induce myocardial fibrosis by targeted inhibiting Smad7 and to promote secretion of TGF-β1 and Fibronecin.