在模拟心肌梗死缺氧微环境中，缺氧诱导因子-1α（HIF-1α）诱导的miR-145表达通过调控血清和糖皮质激素诱导激酶1（SGK1）保护心肌细胞免受凋亡。

Inducible miR-145 expression by HIF-1a protects cardiomyocytes against apoptosis via regulating SGK1 in simulated myocardial infarction hypoxic microenvironment.

作者信息

Sun Nianzi, Meng Fanyan, Xue Ning, Pang Guanghui, Wang Qingxin, Ma Hongliang

机构信息

Linyi People's Hospital.

出版信息

Cardiol J. 2018;25(2):268-278. doi: 10.5603/CJ.a2017.0105. Epub 2017 Oct 5.

DOI:10.5603/CJ.a2017.0105

PMID:28980287

Abstract

BACKGROUND

Myocardial infarction (MI) is partly due to myocardial cell damage caused by hypoxia. MicroRNAs (miRNAs) have been proved to be closely related to the development and progression of many cardiovascular diseases. This study investigated the role of miR-145 in cardiomyocytes under hypoxic condition.

METHODS

The quantitative real-time polymerase chain reaction (qRT-PCR) was performed to test miR-145 expression in H9c2 cells with hypoxia-inducible factor (HIF)-a abnormal expression under hypoxic condition. The 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyltetrazolium bromide (MTT), Tran-swell assay and flow cytometry were used to investigate the effects of miR-145 on cell viability, migration and apoptosis under normoxic or hypoxic condition, respectively. Meanwhile, reactive oxygen species (ROS) content in hypoxic H9c2 cells was analyzed. Western blotting was used to explore the potential mechanism of miR-145 protective effects on cardiomyocytes. Expression levels of miR-145 and SGK1 in rat MI model were also assessed.

RESULTS

Results showed that miR-145 was upregulated in H9c2 and HL-1 cells under hypoxic condi-tion, which was promoted by HIF-1a. MiR-145 overexpression enhanced cell viability and migration under normoxic condition. Under hypoxic condition, miR-145 overexpression promoted cell viability, inhibited apoptosis and ROS activity. Western blotting results proved that miR-145 overexpression inhibited the activation of apoptotic related factors, and promoted activation of PI3K/AKT signaling pathway via SGK1 upregulation. Expression levels of miR-145 and SGK1 were both upregulated in rat MI models.

CONCLUSIONS

HIF-1a could induce miR-145 upregulation in hypoxic H9c2 and HL-1 cells. MiR-145 protected H9c2 cells against hypoxic damage. SGK1 upregulation and activated PI3K/AKT may have participated in the protective effects of miR-145 on cardiomyocytes.

摘要

背景

心肌梗死（MI）部分归因于缺氧引起的心肌细胞损伤。微小RNA（miRNA）已被证明与许多心血管疾病的发生和发展密切相关。本研究调查了miR-145在缺氧条件下心肌细胞中的作用。

方法

采用定量实时聚合酶链反应（qRT-PCR）检测缺氧条件下缺氧诱导因子（HIF）-α异常表达的H9c2细胞中miR-145的表达。分别采用3-（4,5-二甲基-2-噻唑基）-2,5-二苯基四氮唑溴盐（MTT）法、Transwell实验和流式细胞术研究miR-145在常氧或缺氧条件下对细胞活力、迁移和凋亡的影响。同时，分析缺氧H9c2细胞中活性氧（ROS）含量。采用蛋白质免疫印迹法探讨miR-145对心肌细胞保护作用的潜在机制。还评估了大鼠MI模型中miR-145和血清/糖皮质激素调节激酶1（SGK1）的表达水平。

结果

结果显示，缺氧条件下H9c2和HL-1细胞中miR-145上调，这是由HIF-1α促进的。miR-145过表达增强了常氧条件下的细胞活力和迁移能力。在缺氧条件下，miR-145过表达促进细胞活力，抑制凋亡和ROS活性。蛋白质免疫印迹结果证明，miR-145过表达抑制凋亡相关因子的激活，并通过上调SGK1促进磷脂酰肌醇-3-激酶/蛋白激酶B（PI3K/AKT）信号通路的激活。大鼠MI模型中miR-145和SGK1的表达水平均上调。