Cai Xinyong, Zou Pengtao, Hong Lang, Chen Yanmei, Zhan Yuliang, Liu Yuanyuan, Shao Liang
Department of Cardiology, Jiangxi Provincial People's Hospital, The First Affiliated Hospital of Nanchang Medical College, No. 92, Aiguo Road, Donghu District, Nanchang, Jiangxi, 330006, People's Republic of China.
Hum Cell. 2023 Nov;36(6):1948-1964. doi: 10.1007/s13577-023-00956-w. Epub 2023 Jul 28.
BNIP3 is reported to be involved in hypoxia-induced mitochondrial defect and cell death in cardiomyocytes. However, little is known about the specific function and molecular mechanism of BNIP3-mediated mitophagy in myocardial ischemia-reperfusion injury (MIRI). Herein, this study explored the mechanism regulating BNIP3-modulated mitophagy in MIRI. Rat cardiomyocytes (H9c2 cells) underwent transfection and hypoxia/reoxygenation (H/R) treatment, followed by cell viability and apoptosis detection. Gain-of-function assays were conducted in rats before MIRI modeling, followed by the monitoring of cardiac changes and the evaluation of cardiac function, myocardial infarction area, and apoptosis in myocardial tissues. The levels of creatine kinase MB (CK-MB), cardiac troponin I (cTnI), lactic dehydrogenase (LDH), reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), p62, and LC3 II/LC3 I were tested in rat serum or H9c2 cells. The co-localization of LC3 and TOMM20 was analyzed. The interaction of BNIP3 with YTHDF2 was assessed. H/R treatment decreased cell viability and p62 and SOD levels while elevating cell apoptosis, the levels of CK-MB, cTnI, LDH, MDA, ROS, and LC3 II/LC3 I, the number of autophagosomes, and the co-localization of LC3 and TOMM20 in cardiomyocytes, which were neutralized by downregulating BNIP3 or upregulating YTHDF2. Moreover, upregulation of YTHDF2 repressed myocardial injury and mitophagy in MIRI rats. Mechanistically, YTHDF2 mediated BNIP3 expression by recognizing methylated BNIP3. Upregulation of BNIP3 counteracted the suppressive effect of YTHDF2 overexpression on H/R-induced injury and mitophagy in cardiomyocytes. The RNA methylation reading protein YTHDF2 ameliorated MIRI by downregulating BNIP3 via mA modification.
据报道，BNIP3参与缺氧诱导的心肌细胞线粒体缺陷和细胞死亡。然而，关于BNIP3介导的线粒体自噬在心肌缺血再灌注损伤（MIRI）中的具体功能和分子机制知之甚少。在此，本研究探讨了MIRI中调节BNIP3介导的线粒体自噬的机制。对大鼠心肌细胞（H9c2细胞）进行转染和缺氧/复氧（H/R）处理，随后检测细胞活力和凋亡。在MIRI建模前对大鼠进行功能获得性实验，随后监测心脏变化并评估心脏功能、心肌梗死面积和心肌组织中的凋亡情况。检测大鼠血清或H9c2细胞中肌酸激酶MB（CK-MB）、心肌肌钙蛋白I（cTnI）、乳酸脱氢酶（LDH）、活性氧（ROS）、丙二醛（MDA）、超氧化物歧化酶（SOD）、p62和LC3 II/LC3 I的水平。分析LC3和TOMM20的共定位情况。评估BNIP3与YTHDF2的相互作用。H/R处理降低了细胞活力、p62和SOD水平，同时提高了细胞凋亡率、CK-MB、cTnI、LDH、MDA、ROS和LC3 II/LC3 I的水平、自噬体数量以及心肌细胞中LC3和TOMM20的共定位，下调BNIP3或上调YTHDF2可中和这些变化。此外，YTHDF2的上调抑制了MIRI大鼠的心肌损伤和线粒体自噬。机制上，YTHDF2通过识别甲基化的BNIP3介导BNIP3的表达。BNIP3的上调抵消了YTHDF2过表达对H/R诱导的心肌细胞损伤和线粒体自噬的抑制作用。RNA甲基化阅读蛋白YTHDF2通过mA修饰下调BNIP3改善了MIRI。
