微小RNA-133b对心肌纤维化的影响

目的 研究微小RNA-133b(miR-133b)对心肌纤维化的影响。方法 选取人心肌成纤维细胞(CFs),采用CCK8检测过表达及敲低miR-133b时细胞增殖情况,qRT-PCR及Western blot检测结缔组织生长因子(CTGF)、α平滑肌肌动蛋白(α-SMA)、Ⅰ型胶原蛋白(collagenⅠ)及Ⅲ型胶原蛋白(collagen Ⅲ)的表达水平;生物学软件预测miR-133b的靶基因,双荧光素酶报告实验证实miR-133b与靶基因的直接调控作用。 结果 qRT-PCR检测结果显示,转染miR-133b mimic后miR-133b的表达水平明显高于阴性对照组(t=26.219,P=0.000),转染miR-133b inhibitor后miR-133b的表达水平明显低于阴性对照组(t=6.738,P=0.003)。转染CFs 21、45、69、93和117 h后,与阴性对照组相比,miR-133b mimic组CFs增殖能力明显降低,而miR-133b inhibitor组CFs增殖水平明显上升(P均<0.05)。与阴性对照组相比,过表达miR-133b后,CTGF(t=9.213,P=0.001;t=8.195,P=0.001)、α-SMA(t=6.511,P=0.003;t=4.434,P=0.011)、collagenⅠ(t=3.172,P=0.034;t=4.053,P=0.015)及collagen Ⅲ(t=6.404,P=0.003;t=5.319,P=0.006)的mRNA和蛋白表达水平均明显下调;敲低miR-133b后,CTGF(t=9.439,P=0.001;t=14.100,P=0.000)、α-SMA(t=4.519,P=0.011;t=4.377,P=0.012)、collagenⅠ(t=5.966,P=0.004;t=5.514,P=0.005)及collagen Ⅲ(t=4.622,P=0.010;t=4.996,P=0.008)的mRNA和蛋白表达水平均明显上升。共转染miR-133b mimic和WT 3’UTR表达载体细胞的相对荧光素酶活性明显低于共转染mimic control和WT 3’UTR表达载体的细胞(t=5.654,P=0.005),共转染miR-133b mimic和MUT 3’UTR表达载体细胞的相对荧光素酶活性与共转染mimic control和MUT 3’UTR表达载体的细胞差异无统计学意义(t=0.380,P=0.724)。结论 miR-133b可能是通过靶向抑制CTGF来影响CFs的活化增殖,从而改善心肌纤维化。

Effect of microRNA-133b on Myocardial Fibrosis

Objective To investigate the effect of microRNA-133b(miR-133b)on cardiac fibrosis and its mechanism.Methods Human cardiac fibroblasts(CFs)were harvested.The proliferation of CFs was detected by CCK8 during the overexpression and knock-down of miR-133b.The expressions of connective tissue growth factor(CTGF),α-smooth muscle actin(α-SMA),collagen Ⅰ,and collagen Ⅲ were detected with qRT-PCR and Western blot analysis after miR-133b overexpression or downexpression.Target genes of miR-133b were predicted by bioinformatics software.Dual-luciferase activity assay were used to verify a target gene of miR-133b.Results qRT-PCR showed that the expression level of miR-133b in the miR-133b mimic group was significantly higher than that in the negative control group(t=26.219,P=0.000).The expression level of miR-133b in the miR-133b inhibitor group was significantly lower than that in the negative control group(t=6.738,P=0.003).After 21,45,69,93,and 117 hours of transfection,the proliferation ability of CFs significantly decreased in the miR-133b mimic group but significantly increased in the miR-133b group(all P<0.05,compared with the negative control group).After overexpression of miR-133b,the mRNA and protein levels of CTGF(t=9.213,P=0.001;t=8.195,P=0.001),α-SMA(t=6.511,P =0.003;t=4.434,P=0.011),collagenⅠ(t=3.172,P=0.034;t=4.053,P=0.015)and collagen Ⅲ(t=6.404,P=0.003;t=5.319,P=0.006)were significantly down-regulated.After the expression of miR-133b was knocked down,the mRNA and protein levels of CTGF(t=9.439,P=0.001;t=14.100,P=0.000),α-SMA(t=4.519,P=0.011;t=4.377,P=0.012),collagen Ⅰ(t=5.966,P=0.004;t=5.514,P=0.005)and collagen Ⅲ(t=4.622,P=0.010;t=4.996,P=0.008)were significantly increased.The relative luciferase activity of the cells co-transfected with miR-133b mimic and WT 3’UTR expression vector was significantly lower than that of the cells co-transfected with mimic control and WT 3’UTR expression vectors(t=5.654,P=0.005);however,there was no significant difference in relative luciferase activity between cells co-transfected with miR-133b mimic and MUT 3’UTR expression vectors and cells co-transfected with mimic control and MUT 3’UTR expression vectors(t=0.380,P=0.724).Conclusion miR-133b may affect the activation and proliferation of CFs by targeting CTGF and thus improve cardiac fibrosis.