Department of Emergency, Shengli Oilfield Central Hospital, Dongying, China.
J Cell Physiol. 2019 Dec;234(12):22103-22115. doi: 10.1002/jcp.28773. Epub 2019 May 6.
microRNAs (miRNAs) are pleiotropic players in cardiac development. Recent evidence have suggested miRNAs as promisingly therapeutic targets for cardiac regeneration. This study aimed to reveal the potential effects of miR-25 on cardiomyocytes proliferation and migration. Sprague-Dawley rats received left coronary occlusion surgery to induce an in vivo model of myocardial ischemia/reperfusion (I/R) injury. Expression changes of miR-25 and Bim were tested by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and western blot. Besides, primary neonatal and adult cardiomyocytes were transfected by the antisense oligonucleotides or mimic specific for miR-25, and then 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), 5-ethynyl-2'-deoxyuridine (EdU), Boyden chamber, and terminal-deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) assay were respectively used to determine cardiomyocytes growth and migration. Binding effects of miR-25 on the 3'-untranslated region (3'-UTR) of Bim was assessed by dual-luciferase reporter assay. We found that miR-25 was low expressed, whereas Bim was highly expressed in I/R injury model and hypoxia-stimulated cardiomyocytes. Downregulation of miR-25 in neonatal and adult cardiomyocytes markedly reduced cell proliferation and migration, but promoted apoptosis. Consistently, downregulation of miR-25 decreased the expression of cyclin E2, cyclin D1, and CDK4, and increased the expression of p57 (KIP2) in cardiomyocytes. We additionally found that Bim was a target of miR-25. The inhibitory effects of miR-25 downregulation on cardiomyocytes survival and migration were all significantly attenuated when Bim was silenced. To sum up, our study demonstrates that miR-25 downregulation inhibits cardiomyocytes proliferation and migration, but promotes apoptosis. The role of miR-25 in cardiomyocytes was by targeting Bim.
微小 RNA（miRNAs）是心脏发育中的多效性调节因子。最近的证据表明，miRNAs 作为心脏再生有前途的治疗靶点。本研究旨在揭示 miR-25 对心肌细胞增殖和迁移的潜在影响。Sprague-Dawley 大鼠接受左冠状动脉结扎手术，以诱导体内心肌缺血/再灌注（I/R）损伤模型。通过定量逆转录聚合酶链反应（qRT-PCR）和 Western blot 检测 miR-25 和 Bim 的表达变化。此外，原代新生和成年心肌细胞分别用针对 miR-25 的反义寡核苷酸或模拟物转染，然后分别用 3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四唑溴盐（MTT）、5-乙炔基-2'-脱氧尿苷（EdU）、Boyden 室和末端脱氧核苷酸转移酶介导的缺口末端标记（TUNEL）检测试剂盒分别检测心肌细胞的生长和迁移。双荧光素酶报告基因检测评估 miR-25 对 Bim 3'-非翻译区（3'-UTR）的结合作用。结果发现，在 I/R 损伤模型和低氧刺激的心肌细胞中，miR-25 表达下调，而 Bim 表达上调。在新生和成年心肌细胞中下调 miR-25 可显著降低细胞增殖和迁移，但促进细胞凋亡。一致地，下调 miR-25 可降低心肌细胞中细胞周期蛋白 E2、细胞周期蛋白 D1 和 CDK4 的表达，增加 p57（KIP2）的表达。我们还发现 Bim 是 miR-25 的靶基因。当沉默 Bim 时，miR-25 下调对心肌细胞存活和迁移的抑制作用均显著减弱。总之，本研究表明 miR-25 下调抑制心肌细胞增殖和迁移，但促进细胞凋亡。miR-25 在心肌细胞中的作用是通过靶向 Bim 实现的。
