Shao Haifeng, Yang Lili, Wang Li, Tang Bozan, Wang Jian, Li Qiang
Department of Cardiology, The Third Affiliated Hospital of Qiqihar Medical University, Qiqihar 161000, China.
Biochem Cell Biol. 2018 Jun;96(3):349-354. doi: 10.1139/bcb-2016-0158. Epub 2017 May 25.
ischemia-reperfusion (I/R) is a consequence of restored blood supply after myocardial infarction. Myocardial I/R injury can be alleviated by reducing autophagy in heart tissue. MicroRNA-34a (miR-34a) has been shown to regulate autophagy in a renal model of I/R, but it is not known whether it can protect cardiac tissues from I/R injury. This study investigated how miR-34a protects myocardial cells from I/R injury by inhibiting autophagy via regulation of tumor necrosis factor α (TNFα).
we constructed an I/R model in vivo using Langendorff perfusion, and we constructed an in vivo model by treating neonatal rat cardiomyocytes (NRCMs) with hypoxia-reoxygenation (H/R method). Transfected adenoviral-overexpressed miR-34a mimics and controlled NRCMs after H/R. We analyzed cell viability using the MTT assay and a cell counting kit-8 (CCK-8) assay. Changes in the rate of apoptosis were detected by flow cytometry. We investigated the effect mechanisms of miR-34a with Western blot and luciferase assays.
miR-34a expression decreased after in vivo reperfusion of the myocardial cells and heart tissues of neonatal rats. MiR-34a reduced apoptosis of the NRCMs and autophagy levels, simultaneously, after H/R injury. Further, miR-34a decreased the expression of Lc3-II and p62, indicating that miR-34a reduces myocardial I/R injury by decreasing TNFα expression.
miR-34a can inhibit autophagy levels after I/R by targeting TNFα, thereby reducing myocardial injury.
缺血再灌注（I/R）是心肌梗死后恢复血液供应的结果。心肌I/R损伤可通过减少心脏组织中的自噬来缓解。微小RNA-34a（miR-34a）已被证明在I/R的肾脏模型中调节自噬，但尚不清楚它是否能保护心脏组织免受I/R损伤。本研究调查了miR-34a如何通过调节肿瘤坏死因子α（TNFα）抑制自噬来保护心肌细胞免受I/R损伤。
我们使用Langendorff灌注在体内构建I/R模型，并通过用缺氧复氧（H/R方法）处理新生大鼠心肌细胞（NRCMs）构建体内模型。在H/R后转染腺病毒过表达的miR-34a模拟物并对照NRCMs。我们使用MTT法和细胞计数试剂盒-8（CCK-8）法分析细胞活力。通过流式细胞术检测凋亡率的变化。我们用蛋白质印迹法和荧光素酶测定法研究miR-34a的作用机制。
新生大鼠心肌细胞和心脏组织在体内再灌注后miR-34a表达降低。在H/R损伤后，miR-34a同时降低了NRCMs的凋亡和自噬水平。此外，miR-34a降低了Lc3-II和p62的表达，表明miR-34a通过降低TNFα表达来减少心肌I/R损伤。
miR-34a可通过靶向TNFα抑制I/R后的自噬水平，从而减少心肌损伤。
