Department of Pharmacology, Xiangya School of Pharmaceutical Sciences, Central South University, No.110 Xiangya Road, Changsha, 410078, China.
Department of Cardiovascular Medicine, Xiangya Hospital, Central South University, Changsha, 410008, China.
Cardiovasc Drugs Ther. 2019 Feb;33(1):13-23. doi: 10.1007/s10557-018-06848-8.
Necroptosis is an important form of cell death following myocardial ischemia/reperfusion (I/R) and phosphoglycerate mutase 5 (PGAM5) functions as the convergent point for multiple necrosis pathways. This study aims to investigate whether inhibition of PGAM5 could reduce I/R-induced myocardial necroptosis and the underlying mechanisms.
The SD rat hearts (or H9c2 cells) were subjected to 1-h ischemia (or 10-h hypoxia) plus 3-h reperfusion (or 4-h reoxygenation) to establish the I/R (or H/R) injury model. The myocardial injury was assessed by the methods of biochemistry, H&E (hematoxylin and eosin), and PI/DAPI (propidium iodide/4',6-diamidino-2-phenylindole) staining, respectively. Drug interventions or gene knockdown was used to verify the role of PGAM5 in I/R (or H/R)-induced myocardial necroptosis and possible mechanisms.
The I/R-treated heart showed the injuries (increase in infarct size and creatine kinase release), upregulation of PGAM5, dynamin-related protein 1 (Drp1), p-Drp1-S616, and necroptosis-relevant proteins (RIPK1/RIPK3, receptor-interacting protein kinase 1/3; MLKL, mixed lineage kinase domain-like); these phenomena were attenuated by inhibition of PGAM5 or RIPK1. In H9c2 cells, H/R treatment elevated the levels of PGAM5, RIPK1, RIPK3, MLKL, Drp1, and p-Drp1-S616 and induced mitochondrial dysfunctions (elevation in mitochondrial membrane potential and ROS level) and cellular necrosis (increase in LDH release and the ratio of PI/DAPI cells); these effects were blocked by inhibition or knockdown of PGAM5.
Inhibition of PGAM5 can reduce necroptosis in I/R-treated rat hearts through suppression of Drp1; there is a positive feedback between RIPK1 and PGAM5, and PGAM5 might serve as a novel therapeutic target for prevention of myocardial I/R injury.
细胞坏死是心肌缺血/再灌注（I/R）后一种重要的细胞死亡形式，磷酸甘油酸变位酶 5（PGAM5）作为多种坏死途径的汇聚点发挥作用。本研究旨在探讨抑制 PGAM5 是否可以减少 I/R 诱导的心肌坏死和潜在机制。
SD 大鼠心脏（或 H9c2 细胞）进行 1 小时缺血（或 10 小时缺氧）加 3 小时再灌注（或 4 小时复氧）以建立 I/R（或 H/R）损伤模型。通过生化、H&E（苏木精和伊红）和 PI/DAPI（碘化丙啶/4',6-二脒基-2-苯基吲哚）染色分别评估心肌损伤。药物干预或基因敲低用于验证 PGAM5 在 I/R（或 H/R）诱导的心肌坏死中的作用及其可能的机制。
I/R 处理的心脏显示出损伤（梗死面积增加和肌酸激酶释放增加）、PGAM5、动力相关蛋白 1（Drp1）、p-Drp1-S616 和坏死相关蛋白（RIPK1/RIPK3、受体相互作用蛋白激酶 1/3；MLKL、混合谱系激酶结构域样）上调；这些现象通过抑制 PGAM5 或 RIPK1 得到减弱。在 H9c2 细胞中，H/R 处理升高了 PGAM5、RIPK1、RIPK3、MLKL、Drp1 和 p-Drp1-S616 的水平，并诱导线粒体功能障碍（线粒体膜电位和 ROS 水平升高）和细胞坏死（LDH 释放增加和 PI/DAPI 细胞比例增加）；这些作用通过抑制或敲低 PGAM5 得到阻断。
通过抑制 Drp1，抑制 PGAM5 可以减少 I/R 处理的大鼠心脏中的坏死。RIPK1 和 PGAM5 之间存在正反馈，PGAM5 可能成为预防心肌 I/R 损伤的新治疗靶点。
