MIR-138-5p 通过靶向组蛋白去乙酰化酶调节心脏肥大

目的:探究MIR-138-5p 对心脏肥大的影响及其机制。方法:首先构建体外心脏肥大的模型，HE 染色、α-肌动蛋白染色和RT-PCR 方法，分别检测模型大鼠心脏的横断面积和血管紧张素Ⅱ（AngⅡ）处理的心肌细胞（H9c2）的表面积和心肌细胞中MIR-138-5p mRNA 表达情况；MIR-138-5p-mimic 转染AngⅡ处理过的H9c2 细胞，α-肌动蛋白染色和Western 印迹分别检测心肌细胞的表面积和心肌肥大标志物的蛋白表达水平；采用TargetScan 在线软件筛选miR-138-5p 的潜在靶基因，并进一步验证。MIR-138-5p-mimic、pcDNA- HDAC4共转染AngⅡ处理过的H9c2 细胞，α-肌动蛋白染色和Western 印迹法分别检测心肌细胞的表面积和心肌肥大标志物的蛋白表达水平。结果:相对于Sham 组，模型大鼠的心脏体积及心脏横截面均明显增大，心肌细胞中的MIR-138-5p mRNA 表达水平明显降低（F=21.578，P<0.001）；相对于Con 组，AngⅡ组心肌细胞的表面积明显增大，且MIR-138-5p mRNA 表达水平明显降低（F=23.790，P<0.001）。相对于AngⅡ+miR-NC 组，AngⅡ+miR-mimic 组心肌细胞的表面积（F=8.325，P<0.01）、心肌肥大标志蛋白表达水平（F=9.532，P<0.01）和心肌细胞中HDAC4 mRNA表达水平明显降低（F=25.530，P<0.001）； 相对于MIR-138-5p-mimic+pcDNA-Con 组，MIR-138-5p- mimic+pcDNA-HDAC4 组心肌细胞的表面积明显减小（F=10.134，P<0.01），心肌肥大标志蛋白表达水平明显升高。结论:MIR-138-5p 通过靶向组蛋白脱乙酰基酶-8（HDAC4）调节心脏肥大反应。

MIR-138-5p regulates cardiac hypertrophy by targeting histone deacetylase

Objective:To explore the effect of MIR-138-5p on cardiac hypertrophy and its mechanism. Methods: Firstly，the model ofcardiac hypertrophy in vitro was constructed. HE staining，α-actin staining and RT-PCR were used to detect the cross-sectional area of themodel rat heart，the surface area of AngⅡ-treated cardiomyocytes（H9c2）and the expression ofMIR-138-5pmRNA in the cardiomyocytes.MIR-138-5p-mimic was transfected into H9c2 cells treated with AngⅡ，α-actin staining and Western-blotting were used to detect thesurface area of cardiomyocytes and the protein expression level of cardiachypertrophy markers. TargetScan online software was used toscreen potential target genes of MIR-138-5p and further verify. MIR-138-5p-mimic，pcDNA-histone deacetylase-4（HDAC4）wereco -transfected into H9c2 cells treated with AngⅡ，α -actin staining and Western -blotting was used to detect the surface area ofcardiomyocytes and the protein expression level of cardiac hypertrophy markers. Results: Compared with the Sham group，the heartvolume and heart cross -section of model rats were significantly increased，and the expression level of MIR -138 -5p mRNA incardiomyocytes was significantly decreased（F=21.578，P <0.001）. Compared with the Con group，the surface area of cardiomyocytes in theAngⅡgroup was significantly increased，and the expression level of MIR-138-5p mRNA was significantly reduced（F=23.790，P <0.001）.Compared with the AngⅡ+ miR-NC group，the surface area of cardiomyocytes （F=8.325，P<0.01）and the expression of cardiachypertrophy marker proteins in the AngⅡ+ miR-mimic group were significantly reduced（F=9.532，P <0.01）. Compared with the AngⅡ+miR-NC group，the AngⅡ+miR-mimic group was found the expression level of HDAC4 mRNA in cardiomyocytes was significantlyreduced（F=25.530，P<0.001）. Compared with the MIR-138-5p-mimic+pcDNA-Con group，the surface area of cardiomyocytes in theMIR-138-5p-mimic+pcDNA-HDAC4 group was significantly reduced（F=10.134，P <0.01），and the expression level of cardiac hypertrophymarker protein was obviously elevated. Conclusion:MIR-138-5p regulates cardiac hypertrophy by targeting HDAC4.