Key Laboratory of Pathobiology, Ministry of Education, Norman Bethune College of Medicine, Jilin University, Changchun, China.
Department of Endocrinology and Metabolism, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China.
Int J Cardiol. 2018 May 15;259:153-162. doi: 10.1016/j.ijcard.2018.01.036.
The AMP-activated protein kinase (AMPK) plays critical roles in growth regulation and metabolism reprogramming. AMPK activation protects cells against apoptosis from injury in different cell and animal models. However, its function in necroptosis remains largely unclear.
In the current study, we demonstrated that AMPK was activated upon necroptosis induction and protected mouse embryonic fibroblasts (MEFs) and cardiomyocytes from N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and reactive oxygen species (ROS) induced necroptosis. Activation of AMPK with chemicals A-769662, 2-deoxyglucose (2-DG), and metformin or constitutively active (CA) AMPK markedly decreased necroptosis and cytotoxicity induced by MNNG. In contrast, AMPK inhibitor compound C, dominant negative (DN) AMPK, as well as AMPK shRNAs increased necroptosis and cytotoxicity induced by MNNG. We further showed that AMPK physically associated with a protein complex containing PGAM5 and Keap1 whereby facilitating Keap1-mediated PGAM5 ubiquitination upon necroptosis induction. The AMPK agonist metformin ameliorated myocardial ischemia and reperfusion (IR) injury and reduced necroptosis through down-regulating the expression of PGAM5 in the Langendorff-perfused rat hearts.
Activation of AMPK protects against necroptosis via promoting Keap1-mediated PGAM5 degradation. Metformin may act as a valuable agent for the protection of myocardial ischemia and reperfusion injury by activating AMPK and reducing necroptosis.
AMP 激活的蛋白激酶 (AMPK) 在生长调控和代谢重编程中发挥着关键作用。AMPK 的激活可保护细胞免受不同细胞和动物模型中损伤诱导的细胞凋亡。然而，其在坏死性凋亡中的作用在很大程度上仍不清楚。
在本研究中，我们证明了 AMPK 在坏死性凋亡诱导时被激活，并保护小鼠胚胎成纤维细胞（MEFs）和心肌细胞免受 N-甲基-N'-硝基-N-亚硝基胍（MNNG）和活性氧（ROS）诱导的坏死性凋亡。用化学物质 A-769662、2-脱氧葡萄糖（2-DG）和二甲双胍或组成型激活（CA）AMPK 激活 AMPK，可显著降低 MNNG 诱导的坏死性凋亡和细胞毒性。相比之下，AMPK 抑制剂化合物 C、显性负（DN）AMPK 以及 AMPK shRNAs 增加了 MNNG 诱导的坏死性凋亡和细胞毒性。我们进一步表明，AMPK 与包含 PGAM5 和 Keap1 的蛋白质复合物物理结合，从而促进坏死性凋亡诱导时 Keap1 介导的 PGAM5 泛素化。AMPK 激动剂二甲双胍通过下调 Langendorff 灌流大鼠心脏中 PGAM5 的表达，改善心肌缺血再灌注（IR）损伤并减少坏死性凋亡。
激活 AMPK 通过促进 Keap1 介导的 PGAM5 降解来保护细胞免于坏死性凋亡。二甲双胍可能通过激活 AMPK 和减少坏死性凋亡来作为一种有价值的心肌缺血再灌注损伤保护剂。
