Upregulation of microRNA-22 contributes to myocardial ischemia-reperfusion injury by interfering with the mitochondrial function
Upregulation of microRNA-22 contributes to myocardial ischemia-reperfusion injury by interfering with the mitochondrial function
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microRNA-22的上调通过干扰线粒体功能导致心肌缺血再灌注损伤
DOI：
10.1016/j.freeradbiomed.2016.05.006
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发表时间：
2016-07-01
影响因子：
7.4
通讯作者：
Ni, Xin
中科院分区：
文献类型：
--
作者：
Du, Jian-Kui;Cong, Bin-Hai;Ni, Xin
线粒体氧化损伤是心肌缺血再灌注（I/R）损伤的重要机制。已经预测MicroRNA-22（miR-22）潜在地靶向sirtuin-1（Sirt 1）和过氧化物酶体增殖物激活受体-γ共激活因子-la（PGC 1 α），已知这两者都提供针对线粒体氧化损伤的保护。本研究旨在探讨miR-22是否通过调节线粒体功能参与心肌I/R损伤的调控。我们发现，与假手术组相比，在I/R损伤的大鼠心脏中，miR-22水平显著增加。心肌内注射20 μ g miR-22抑制剂可减少I/R损伤，心肌梗死面积、血清乳酸脱氢酶（LDH）和肌酸激酶（CK）水平以及凋亡心肌细胞数量显著减少。H9 c2心肌细胞缺氧/复氧（H/R）损伤后miR-22表达增加，活性氧清除剂和p53抑制剂可阻断miR-22表达。此外，miR-22抑制剂减轻了H/R诱导的H9 c2心肌细胞损伤，而miR-22模拟物加重了H/R诱导的H9 c2心肌细胞损伤。MiR-22抑制剂本身对心脏线粒体功能没有显著影响。与接受miR对照的大鼠相比，发现在缺血前48 h接受miR-22抑制剂的大鼠的线粒体具有显著较少的线粒体超氧化物产生和较大的线粒体膜电位和ATP产生。在H9 c2心肌细胞中，发现miR-22模拟物加重，而miR-22抑制剂显著减轻H/R诱导的线粒体损伤。通过使用真实的时间PCR、蛋白质印迹和双荧光素酶报告基因分析，我们鉴定了Sirt 1和PGC 1 α为心肌细胞中的miR-22靶标。发现Sirt 1的沉默消除了miR-22抑制剂对心肌细胞中H/R诱导的线粒体功能障碍和细胞损伤的保护作用。综上所述，我们的研究结果在miRNA水平揭示了心肌I/R损伤期间心脏线粒体功能障碍的新分子机制，并证明了miR-22抑制通过维持心脏线粒体功能对急性心肌I/R损伤的治疗潜力。(C)2016 Elsevier Inc. All rights reserved.
Mitochondrial oxidative damage is critically involved in cardiac ischemia reperfusion (I/R) injury. MicroRNA-22 (miR-22) has been predicted to potentially target sirtuin-1 (Sirt1) and peroxisome proliferator-activated receptor-gamma coactivator-la (PGC1 alpha), both of which are known to provide protection against mitochondrial oxidative injury. The present study aims to investigate whether miR-22 is involved in the regulation of cardiac I/R injury by regulation of mitochondrial function. We found that miR-22 level was significantly increased in rat hearts subjected to I/R injury, as compared with the sham group. Intra-myocardial injection of 20 ug miR-22 inhibitor reduced I/R injury as evidenced by significant decreases in cardiac infarct size, serum lactate dehydrogenase (LDH) and creatine kinase (CK) levels and the number of apoptotic cardiomyocytes. H9c2 cardiomyocytes exposed to hypoxia/reoxygenation (H/R) insult exhibited an increase in miR-22 expression, which was blocked by reactive oxygen species (ROS) scavenger and p53 inhibitor. In addition, miR-22 inhibitor attenuated, whereas miR-22 mimic aggravated H/R-induced injury in H9c2 cardiomyocytes. MiR-22 inhibitor per se had no significant effect on cardiac mitochondrial function. Mitochondria from rat receiving miR-22 inhibitor 48 h before ischemia were found to have a significantly less mitochondrial superoxide production and greater mitochondrial membrane potential and ATP production as compared with rat receiving miR control. In H9c2 cardiomyocyte, it was found that miR-22 mimic aggravated, whilst miR-22 inhibitor significantly attenuated H/R-induced mitochondrial damage. By using real time PCR, western blot and dual-luciferase reporter gene analyses, we identified Sirtl and PGC1 alpha as miR-22 targets in cardiomyocytes. It was found that silencing of Sirtl abolished the protective effect of miR-22 inhibitor against H/R-induced mitochondrial dysfunction and cell injury in cardiomyocytes. Taken together, our findings reveal a novel molecular mechanism for cardiac mitochondrial dysfunction during myocardial I/R injury at the miRNA level and demonstrate the therapeutic potential of miR-22 inhibition for acute myocardial I/R injury by maintaining cardiac mitochondrial function. (C) 2016 Elsevier Inc. All rights reserved.