Department of Cardiothoracic Surgery, Affiliated Hospital of Nantong University, Nantong, Jiangsu, China.
Department of Cardiology, The Second Affiliated Hospital of Nantong University, Nantong, Jiangsu, China.
Eur J Pharmacol. 2023 Sep 5;954:175864. doi: 10.1016/j.ejphar.2023.175864. Epub 2023 Jun 29.
The E3 ubiquitin ligase HMG-CoA reductase degradation protein 1 (Hrd1) is a key enzyme for ER-associated degradation of misfolded proteins. Its role in ischemic heart disease has not been fully elucidated. Here, we investigated its effect on oxidative status and cell survival in cardiac ischemia-reperfusion injury (MIRI). We found that virus-induced down-regulation of Hrd1 expression limited infarct size, decreased creatinine kinase (CK) and lactate dehydrogenase (LDH), and preserved cardiac function in mice subjected to left anterior descending coronary artery ligation and reperfusion. Silencing of the Hrd1 gene also prevented the ischemia/reperfusion (I/R)-induced (i) increase in dihydroethidium (DHE) intensity, mitochondrial production of reactive oxygen species (ROS), malondialdehyde (MDA), and nitric oxide (NO), (ii) decrease in total antioxidant capacity (T-AOC) and glutathione (GSH), (iii) disruption of mitochondrial membrane potential, and (iv) increase in the expression of glucose-regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP) in ischemic heart tissue. In addition, down-regulation of Hrd1 expression prevented the abnormally increased caspase-3/caspase-9/Bax expression and decreased Bcl-2 expression in ischemic heart tissue of I/R mice. Further analysis showed that the I/R stimulus reduced peroxisome proliferation activated receptor α (PPARα) expression in ischemic heart tissue, which was partially prevented by down-regulation of Hrd1. Pharmacological inhibition of PPARα was able to abolish the preventive effect of down-regulation of Hrd1 on oxidative stress, endoplasmic reticulum stress, and cellular apoptosis in ischemic heart tissue. These data suggest that down-regulation of Hrd1 protects the heart from I/R-induced damage by suppressing oxidative stress and cellular apoptosis likely through PPARα.
E3 泛素连接酶 HMG-CoA 还原酶降解蛋白 1（Hrd1）是内质网相关降解错误折叠蛋白的关键酶。但其在缺血性心脏病中的作用尚未完全阐明。在这里，我们研究了它在心肌缺血再灌注损伤（MIRI）中的氧化状态和细胞存活的作用。我们发现，病毒诱导的 Hrd1 表达下调限制了梗死面积，降低了肌酸激酶（CK）和乳酸脱氢酶（LDH），并保持了左前降支冠状动脉结扎和再灌注后小鼠的心脏功能。沉默 Hrd1 基因也防止了缺血/再灌注（I/R）诱导的（i）二氢乙啶（DHE）强度增加、线粒体产生的活性氧（ROS）、丙二醛（MDA）和一氧化氮（NO），（ii）总抗氧化能力（T-AOC）和谷胱甘肽（GSH）减少，（iii）线粒体膜电位破坏，以及（iv）缺血性心肌组织中葡萄糖调节蛋白 78（GRP78）和 C/EBP 同源蛋白（CHOP）的表达增加。此外，下调 Hrd1 表达可防止 I/R 小鼠缺血性心肌组织中 caspase-3/caspase-9/Bax 表达异常增加和 Bcl-2 表达降低。进一步分析表明，I/R 刺激降低了缺血性心肌组织中过氧化物酶体增殖物激活受体α（PPARα）的表达，而 Hrd1 的下调部分阻止了这种表达降低。PPARα 的药理学抑制能够消除下调 Hrd1 对缺血性心肌组织氧化应激、内质网应激和细胞凋亡的预防作用。这些数据表明，下调 Hrd1 通过抑制氧化应激和细胞凋亡来保护心脏免受 I/R 损伤，这可能是通过 PPARα 实现的。
