MiR-30a在血管紧张素Ⅱ诱导的心肌肥厚中的作用

Role of miR-30a on Ang Ⅱ-induced myocardial hypertrophy

目的 探讨miR-30a是否介导了血管紧张素Ⅱ（AngⅡ）诱导的心肌肥厚.方法 将心肌细胞分为对照组和AngⅡ诱导组,用Real-time PCR观察AngⅡ刺激后心肌细胞miR-30a的变化和肥厚基因的表达.将心肌细胞分为对照组和AngⅡ诱导组,用激光共聚焦观察AngⅡ刺激后心肌细胞大小的变化.将心肌细胞分为对照组（AngⅡ＋NC）、miR-30a诱导组（AngⅡ＋miR-30a mimics）和miR-30a抑制组（AngⅡ＋miR-30ainhibitors）,通过对miR-30a过表达或者抑制miR-30a活性后,观察心肌细胞肥厚基因表达和心肌细胞大小的变化.结果 AngⅡ刺激心肌细胞后,心肌细胞miR-30a表达量下调至刺激前的32.9％.AngⅡ＋miR-30amimics组心肌细胞肥厚基因ANP和β-MHC表达分别是negative control组的51.7％和53.5％,AngⅡ＋miR30a inhibitors组心肌细胞肥厚基因ANP和β-MHC表达分别是AngⅡ＋negative control组的1.88倍和1.64倍.激光共聚焦检测形态学的改变,AngⅡ刺激心肌细胞使心肌细胞面积增加至刺激前的2.95倍.与negative control组比较,AngⅡ＋miR-30a mimics组心肌细胞面积减少至57.8％,AngⅡ＋miR-30a inhibitors组心肌细胞面积增加至1.50倍.结论 miR-30a下调可介导AngⅡ诱导的心肌肥厚.

Objective To investigate whether miR-30a could mediate angiotensin Ⅱ （Ang Ⅱ ）-induced myocardial hypertrophy or not. Methods The neonatal cardiomyocytes were divided into control group and Ang Ⅱ-induced group and relative expression of miR-30a and hypertrophy-related genes were analyzed in Ang Ⅱ -stim- ulated cardiomyocytes by real-time PCR. The neonatal cardiomyocytes were divided into control group and Ang Ⅱ- induced group and influence of Ang Ⅱ on relative cell area in cardiomyocytes was evaluated by confocal microscopy. The neonatal cardiomyocytes were divided into control group （Ang Ⅱ＋NC）, miR-30a-induced group （ Ang Ⅱ ＋miR-30a mimics ）and miR-30a-inhibited group （Ang Ⅱ＋miR-30a mimics ）. Influence of miR-30a on mRNA level of ANP and Ⅱ-MHC was evaluated in hypertrophic cardiomyoeytes. Results The expression of miR- 30a in Ang Ⅱ-stimulated eardiomyocytes was only 32.9% of that in unstimulated cells. The expression of ANP and β -MHC was measured in Ang II induced hypertrophic cardiomyocytes, treatment with an miR-30a mimic de- creased the expression of ANP and β-MHC by 48.3% and 46.5%, respectively, relative to the negative control. Conversely, in hypertrophic cardiomyocytes, treatment with an miR-30a inhibitor increased the expression of ANP and β-MHC by 1.88- and 1.64-fold, respectively, relative to the negative control. The morphological observations indicated that the surface area of hypertrophic cardiomyocytes was 2.95-fold that of untreated cells. Compared with hypertrophic cardiomyocytes treated with Ang Ⅱ＋negative control, the cell surface area decreased by 42.2% in cardiomyocytes treated with Ang Ⅱ＋miR-30a mimic, and increased 1.50-fold in cardiomyocytes treated with Ang Ⅱ ＋miR- 30a inhibitor. Conclusion Down-regulation of miR-30a mediates Ang Ⅱ -induced myocardial hypertrophy.