天津医药

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microRNA-21通过促进成纤维细胞的增殖和分化调节心肌梗死后的心脏重塑

郭东1,张闽红2,3,肖清萍2,3,刘建文1   

  1. 1. 江西省吉安市中心人民医院
    2.
    3. 吉安市中心人民医院
  • 收稿日期:2013-06-17 修回日期:2014-01-06 出版日期:2014-05-15 发布日期:2014-05-15
  • 通讯作者: 刘建文

microRNA-21 regulates cardiac remodeling by promoting proliferation and differentiation of fibroblast after myocardial infarction

  • Received:2013-06-17 Revised:2014-01-06 Published:2014-05-15 Online:2014-05-15

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摘要： 目的 探讨小鼠心肌梗死模型中microRNA-21（miR-21）对心脏成纤维细胞增殖和分化的影响。方法 利用左前降支结扎法构建C57/BL6小鼠心肌梗死模型，以心电图及病理改变作为建模成功的观察指标。采用荧光定量PCR（qRT-PCR）检测各组心肌组织miR-21的表达。体外实验分为3组：随机对照组、空白对照组和miR-21 mimic组。利用miR-21的模拟物（miR-21 mimic）转染小鼠成纤维细胞，使其在细胞中呈过表达状态，然后标记5-乙炔基-2′脱氧尿嘧啶核苷（EdU），通过荧光显微镜观察成纤维细胞的增殖情况，并利用蛋白质印迹技术（Western Blot）检测成纤维细胞α平滑肌肌动蛋白（α-SMA）和小鼠Smad同源物7（Smad7）的表达。结果 与假手术组比较，心梗手术组梗死交界区的miR-21的表达量较远端区[（4.839 ±0.705）×10-4 vs（1.620±0.451）×10-4]明显上调（P <0.01）。与随机对照组和空白对照组比较，miR-21 minic组miR-21的表达[（4.839±0.705）×10-4 vs（1.143±0.064）×10-4 vs（1.017±0.201）×10-4]显著上调（P<0.01）。与随机对照组和空白对照组比较，miR-21 minic组成纤维细胞EdU染色阳性率[（27.892±1.645）% vs（12.553±1.227）% vs（13.946±1.550）%]显著增加（P<0.01）；同时，miR-21 minic组成纤维细胞Smad7基因的表达明显下调，而α-SMA的表达显著上调。结论 心肌梗死后，上调的miR-21可以通过调节转化生长因子（TGF）-β信号通路中Smad7的表达促进成纤维细胞的增殖和分化，进而调节心梗后的心脏重塑。

关键词: 心肌梗死, 成纤维细胞, 细胞增殖, 细胞分化, microRNA-21

Abstract: Objective To investigate the role of microRNA-21(miR-21) on cardiac fibroblast proliferation and differentiation in the mouse model of myocardial infarction. Method Male C57BL/6 mice underwent ligation of the left coronary artery to produce models of myocardial infarction (MI). Echocardiographic assessment and histological evaluation were performed after ligation. The expressing levels of miR-21 were measured by quantitative real-time PCR in the various myocardial tissues. The in vitro experiment was divided into control group, blank group and miR-21 minic group. In cardiac fibroblasts stably overexpressing miR-21 by transfection of miR-21 minic, proliferation was assessed by immunostaining for 5-ethynyl-2’-deoxyuridine (EdU). Western Blot was used to detect the expression of α-SMA and Smad7 in the cardiac fibroblasts. Results The expression of miR-21 was significantly increased in border area compared to remote areas in MI group than that of sham group (P<0.01). There was a higher expression of miR-21 in miR-21 minic group than those of control group and blank group (P<0.01). The EdU positive rate was significantly higher in miR-21 minic group than those of control group and blank group (P<0.01). Overexpression of miR-21 in cardiac fibroblasts increased α-SMA level, while Smad7 level, a target gene of miR-21, was significantly decreased. Conclusion Overexpression of miR-21 in cardiac fibroblasts disrupts TGF-β signaling pathway by reducing the expression of Smad7, which promotes the proliferation and differentiation of cardiac fibroblast, and finally regulates cardiac remodeling after myocardial infarction.

Key words: myocardial infarction, fibroblasts, cell proliferation, cell differentiation, microRNA-21