Department of Cardiology, The Center Hospital of Shaoyang, Shaoyang, China.
PeerJ. 2022 Aug 5;10:e13823. doi: 10.7717/peerj.13823. eCollection 2022.
Hypoxia and reoxygenation (H/R) play a prevalent role in heart-related diseases. Histone demethylases are involved in myocardial injury. In this study, the mechanism of the lysine-specific histone demethylase 1A (KDM1A/LSD1) on cardiomyocyte apoptosis after myocardial ischemia-reperfusion injury (MIRI) was investigated. Firstly, HL-1 cells were treated with H/R to establish the MIRI models. The expressions of KDM1A and Sex Determining Region Y-Box Transcription Factor 9 (SOX9) in H/R-treated HL-1 cells were examined. The cell viability, markers of myocardial injury (LDH, AST, and CK-MB) and apoptosis (Bax and Bcl-2), and Caspase-3 and Caspase-9 protein activities were detected, respectively. We found that H/R treatment promoted cardiomyocyte apoptosis and downregulated KDM1A, and overexpressing KDM1A reduced apoptosis in H/R-treated cardiomyocytes. Subsequently, tri-methylation of lysine 4 on histone H3 (H3K4me3) level on the SOX9 promoter region was detected. We found that KDM1A repressed SOX9 transcription by reducing H3K4me3. Then, HL-1 cells were treated with CPI-455 and plasmid pcDNA3.1-SOX9 and had joint experiments with pcDNA3.1-KDM1A. We disclosed that upregulating H3K4me3 or overexpressing SOX9 reversed the inhibitory effect of overexpressing KDM1A on apoptosis of H/R-treated cardiomyocytes. In conclusion, KDM1A inhibited SOX9 transcription by reducing the H3K4me3 on the SOX9 promoter region and thus inhibited H/R-induced apoptosis of cardiomyocytes.
缺氧和再氧合（H/R）在心脏相关疾病中起着重要作用。组蛋白去甲基化酶参与心肌损伤。在这项研究中，研究了赖氨酸特异性组蛋白去甲基酶 1A（KDM1A/LSD1）在心肌缺血再灌注损伤（MIRI）后心肌细胞凋亡中的作用机制。首先，用 H/R 处理 HL-1 细胞建立 MIRI 模型。检测 H/R 处理的 HL-1 细胞中 KDM1A 和性决定区 Y 框转录因子 9（SOX9）的表达。检测细胞活力、心肌损伤标志物（LDH、AST 和 CK-MB）和凋亡标志物（Bax 和 Bcl-2）以及 Caspase-3 和 Caspase-9 蛋白活性。结果发现，H/R 处理促进心肌细胞凋亡，下调 KDM1A，过表达 KDM1A 可减少 H/R 处理的心肌细胞凋亡。随后，检测 SOX9 启动子区域组蛋白 H3 赖氨酸 4 三甲基化（H3K4me3）水平。结果发现，KDM1A 通过降低 H3K4me3 抑制 SOX9 转录。然后，用 CPI-455 和 pcDNA3.1-SOX9 质粒处理 HL-1 细胞，并与 pcDNA3.1-KDM1A 进行联合实验。结果表明，上调 H3K4me3 或过表达 SOX9 逆转了过表达 KDM1A 对 H/R 处理的心肌细胞凋亡的抑制作用。结论：KDM1A 通过降低 SOX9 启动子区域的 H3K4me3 抑制 SOX9 转录，从而抑制 H/R 诱导的心肌细胞凋亡。
