Yang Jian, Fan Zhixing, Yang Jun, Ding Jiawang, Yang Chaojun, Chen Lihua
Department of Cardiology, Institute of Cardiovascular Diseases, The First College of Clinical Medical Sciences, China Three Gorges University, Yichang, Hubei 443000, P.R. China.
Department of Optometry and Ophthalmology, Yichang Central People's Hospital, China Three Gorges University, Yichang, Hubei 443000, P.R. China.
Exp Ther Med. 2016 Nov;12(5):3249-3255. doi: 10.3892/etm.2016.3777. Epub 2016 Oct 4.
Previous studies have reported that microRNA-22 (miR-22) may be implicated in ischemia-reperfusion (I/R)-induced myocardial injury. Our previously published data also demonstrated that miR-22 may protect against myocardial I/R injury via anti-apoptosis in rats by targeting cAMP response element-binding protein binding protein (CBP). However, the specific function of miR-22 in myocardial I/R injury is far from fully elucidated. The present study was designed to investigate another cardioprotective signaling mechanism of miR-22 in myocardial I/R injury. A total of 40 adult male Sprague-Dawley rats were randomly divided into four equal groups (n=10): Sham, myocardial I/R, myocardial I/R with adenovirus expressing scramble miRNA (Ad-Scramble) and myocardial I/R with adenovirus expressing miR-22 (Ad-miR-22) groups. Besides the Sham operation group, the remaining three groups were artificially afflicted with coronary occlusion for 30 min and subsequently reperfused for 4 h. A light microscope was used to observe structural changes in the myocardium; reverse transcription polymerase chain reaction was used to measure the miR-22 mRNA expression level; the myocardial infarct size was analyzed by the Evans Blue/triphenyltetrazolium chloride double-staining; and p38 mitogen-activated protein kinase (MAPK), CBP, c-Jun-activator protein (AP)-1 and phospho (p)-c-Jun-AP-1 expression protein levels were detected by a western blot. Furthermore, ELISA was used to measure the levels of TNF-α and IL-6 in the myocardium. The results demonstrated that adenovirus-mediated miR-22 overexpression markedly reduced p38 MAPK, CBP, c-Jun-AP-1, p-c-Jun-AP-1 expression levels concomitant with an improvement in myocardial injury, including smaller infarct size, reduced release of creatine kinase, lactate dehydrogenase and proinflammation mediators (tumor necrosis factor-α and interleukin-6). These findings suggest that miR-22 has a protective effect on myocardial I/R injury. This protection mechanism, at least in part, is due to its anti-inflammatory function via the suppression of the p38 MAPK/CBP/c-Jun-AP-1 signaling pathway.
先前的研究报道，微小RNA-22（miR-22）可能与缺血再灌注（I/R）诱导的心肌损伤有关。我们之前发表的数据也表明，miR-22可能通过靶向环磷酸腺苷反应元件结合蛋白结合蛋白（CBP），在大鼠中通过抗凋亡作用来保护心肌免受I/R损伤。然而，miR-22在心肌I/R损伤中的具体功能远未完全阐明。本研究旨在探究miR-22在心肌I/R损伤中的另一种心脏保护信号机制。总共40只成年雄性Sprague-Dawley大鼠被随机分为四组，每组10只：假手术组、心肌I/R组、心肌I/R联合表达乱序微小RNA的腺病毒组（Ad-Scramble）和心肌I/R联合表达miR-22的腺病毒组（Ad-miR-22）。除假手术组外，其余三组均进行冠状动脉闭塞30分钟，随后再灌注4小时。使用光学显微镜观察心肌结构变化；采用逆转录聚合酶链反应测量miR-22 mRNA表达水平；通过伊文思蓝/氯化三苯基四氮唑双重染色分析心肌梗死面积；采用蛋白质免疫印迹法检测p38丝裂原活化蛋白激酶（MAPK）、CBP、c-Jun活化蛋白（AP）-1和磷酸化（p）-c-Jun-AP-1的表达蛋白水平。此外，采用酶联免疫吸附测定法测量心肌中肿瘤坏死因子-α（TNF-α）和白细胞介素-6（IL-6）的水平。结果表明，腺病毒介导的miR-22过表达显著降低了p38 MAPK、CBP、c-Jun-AP-1、p-c-Jun-AP-1的表达水平，同时改善了心肌损伤，包括梗死面积减小、肌酸激酶、乳酸脱氢酶和促炎介质（肿瘤坏死因子-α和白细胞介素-6）释放减少。这些发现表明，miR-22对心肌I/R损伤具有保护作用。这种保护机制至少部分是由于其通过抑制p38 MAPK/CBP/c-Jun-AP-1信号通路发挥的抗炎功能。
