微小RNA451a对心肌肥厚的影响

Effect of miRNA-451a on cardiac hypertrophy

目的探讨微小RNA(miRNA)-451a在心肌肥厚的作用。方法腹主动脉缩窄术(abodminal aortic constriction,AAC)建立大鼠心肌肥厚模型,超声检测、心肌肥厚指数及组织病理学观察评估模型建立效果,蛋白印迹检测LC3II/I的比值,实时定量聚合酶链反应(quantiative real-time polymerase chain reaction,qRT-PCR)检测心肌miRNA-451a及肥厚标志基因的表达。乳鼠心肌细胞分空白对照组及异丙肾上腺素(isoproterenol,ISO)组,qRT-PCR检测miRNA-451a及肥厚标志分子基因的表达,免疫荧光测定细胞表面积及测定LC3II/I的比值。乳鼠心肌细胞分4组,即miR-451a mimic组及其阴性对照组、miR-451a inhibitor组及其阴性对照组,分别转染乳鼠心肌细胞24 h再予ISO处理48 h,qRT-PCR检测肥厚标志基因的表达,测定细胞表面积及LC3II/I比值。结果 AAC组大鼠心肌肥厚模型建立成功,其肥厚标志基因表达上调,miRNA-451a表达下调,LC3II/I比值增大。ISO组心肌细胞比空白对照组肥厚标志基因表达上调,miRNA-451a表达下调,LC3II/I比值及细胞表面积增大。miRNA-451a mimic+ISO组心肌细胞比阴性对照组肥厚标志基因表达下调,细胞表面积及LC3II/I比值减小;而miRNA-451a inhibitor+ISO组心肌细胞则表现相反。结论 miRNA-451a可能在心肌肥厚过程中具有调控作用。

Objectives To investigate the role of miRNA-45 l a on cardiac hypertrophy. Methods We induced cardiac hypertrophy rat model by abdominal aortic constriction, evaluated the effect of model by ultrasonic testing, cardiac hypertrophy index measurement and histopathologic observation. Expressions of miRNA-451a and hypertrophy-related genes were analyzed by quantiative real-time polymerase chain reaction （qRT-PCR） and ration of LC3II/I was calculated by Western-blotting. Neonatal cardiomyocytes were isolated and divided into control group and isoproterenol （ISO） group. Expression of miRNA-451a and hypertrophy-related genes were all analyzed. LC3II/I ratio will be calculated and cell area were measured by immunofluorescence. Neonatal eardiomyocytes were divided into four groups to transfect with different treats for 24 h： miRNA-451a mimic and miRNA mimic negative control groups, miRNA-451a inhibitor and miRNA inhibitor negative control groups. Then, the ceils were treated with ISO for 48 h. Expression of hypertrophy-related genes were analyzed. LC3II/I ratio and cell area were also calculated. Results AAC rat model of cardiac hypertrophy was well established and the expression of both hypertrophy-related genes and LC3II/I upregulated, whereas expression of miRNA-451a downregulated. Cardiomyocytes of ISO group showed upregulation of hypertrophy- related genes and LC3II/I ratio except for downregulation of miRNA-451a. Expression of hypertrophy-related genes downregulated in miRNA-45 la mimic＋ISO group when compared with negative control group, with increased cell area and LC3II/I ratio. Expression of hypertrophy-related genes upregulated in miRNA-451a inhibitor＋ISO group when compared with negative control group, with increased cell area and LC3II/I ratio. Conclusions miRNA-451a may play a regulatory role in cardiac hypertrophy.