Wang Peng, Shen Cheng, Diao Lei, Yang Zhiyin, Fan Fan, Wang Cong, Liu Xiangwei, Sun Xiaolei, Dong Zhen, Zhu Hong, Ma Xin, Cao Quan, Zhao Xiaona, Ma Duan, Zou Yunzeng, Hu Kai, Sun Aijun, Ge Junbo
Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital, Fudan University, Shanghai 200032, China ; Department of Cardiology, Shandong University, Jinan, Shandong 250012, China.
Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China.
Biomed Res Int. 2015;2015:503692. doi: 10.1155/2015/503692. Epub 2015 Jan 5.
Aldehyde dehydrogenase 2 (ALDH2) plays a crucial role in myocardial protection against ischemia. Downregulation of ALDH2 was evidenced after myocardial infarction and the underlying mechanism is not fully understood. DNA methylation can regulate gene transcription in epigenetic level. We thus hypothesized that DNA methylation may affect ALDH2 expression in myocardial infarction (MI).
MI was induced in Sprague-Dawley rats. MI border zone tissues were harvested at 1st week, 2nd week, and 3rd week after MI. Bisulfite sequencing PCR (BSP) was performed to detect the methylation levels of ALDH2 core promoter. Sequenom MassARRAY platform (MassARRAY) was used to examine the methylation levels of ALDH2 promoter upstream sequence. ALDH2 protein and mRNA expression were assayed by Western blot and real-time PCR, respectively.
Compared with Sham group, ALDH2 protein and mRNA expression of MI groups was significantly downregulated. Compared with Sham group, DNA methylation level of CpG sites in ALDH2 promoter upstream sequence was significantly higher in MI groups in a time-dependent manner (CpG1, CpG2, and CpG7, P < 0.01). DNA methylation did not affect ALDH2 core promoter sequence during the progress of MI. No significant difference was detected in DNA methylation level of ALDH2 promoter upstream sequence among MI groups.
Aberrant hypermethylation of CpG sites in ALDH2 promoter upstream sequence is associated with myocardial ischemia injury and may partly result in ALDH2 downregulation after MI.
乙醛脱氢酶2（ALDH2）在心肌缺血保护中起关键作用。心肌梗死后有证据表明ALDH2表达下调，但其潜在机制尚未完全阐明。DNA甲基化可在表观遗传水平调节基因转录。因此，我们推测DNA甲基化可能影响心肌梗死（MI）时ALDH2的表达。
在Sprague-Dawley大鼠中诱导MI。在MI后第1周、第2周和第3周采集MI边缘区组织。采用亚硫酸氢盐测序PCR（BSP）检测ALDH2核心启动子的甲基化水平。使用Sequenom MassARRAY平台（MassARRAY）检测ALDH2启动子上游序列的甲基化水平。分别通过蛋白质免疫印迹法和实时PCR检测ALDH2蛋白和mRNA表达。
与假手术组相比，MI组的ALDH2蛋白和mRNA表达显著下调。与假手术组相比，MI组中ALDH2启动子上游序列中CpG位点的DNA甲基化水平呈时间依赖性显著升高（CpG1、CpG2和CpG7，P<0.01）。在MI进展过程中，DNA甲基化不影响ALDH2核心启动子序列。MI组之间ALDH2启动子上游序列的DNA甲基化水平未检测到显著差异。
ALDH2启动子上游序列中CpG位点的异常高甲基化与心肌缺血损伤相关，可能是MI后ALDH2下调的部分原因。
