Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Fujian Medical University, No. 20 Chazhong Road, Taijiang District, Fuzhou 350005, China.
The Second Affiliated Hospital of Fujian Medical University, No. 34 Zhongshan North Road, Licheng District, Quanzhou 362000, China.
Oxid Med Cell Longev. 2019 May 7;2019:6581217. doi: 10.1155/2019/6581217. eCollection 2019.
MicroRNAs (miRNAs) have emerged as key modulators in the pathophysiologic processes of cardiovascular diseases. However, its function in cardiac injury induced by obstructive sleep apnea (OSA) remains unknown. The aim of the current study was to identify the effect and potential molecular mechanism of miR-146a-5p in intermittent hypoxia(IH)- induced myocardial damage. We exposed H9c2 cells to IH condition; the expression levels of miR-146a-5p were detected by RT-qPCR. Cell viability, cell apoptosis, and the expressions of apoptosis-associated proteins were assessed via Cell Counting Kit-8 (CCK-8), flow cytometry, and western blotting, respectively. Target genes of miR-146a-5p were confirmed by dual-luciferase reporter assay. IH remarkably lowered viability but enhanced cell apoptosis. Concomitantly, the miR-146a-5p expression level was increased in H9c2 cells after IH. Subsequent experiments showed that IH-induced injury was alleviated through miR-146a-5p silence. X-linked inhibitor of apoptosis protein (XIAP) was predicted by bioinformatics analysis and further confirmed as a direct target gene of miR-146a-5p. Surprisingly, the effect of miR-146a-5p inhibition under IH may be reversed by downregulating XIAP expression. In conclusion, our results demonstrated that miR-146a-5p could attenuate viability and promote the apoptosis of H9c2 by targeting XIAP, thus aggravating the H9c2 cell injury induced by IH, which could enhance our understanding of the mechanisms for OSA-associated cardiac injury.
微小 RNA（miRNA）已成为心血管疾病病理生理过程中的关键调节因子。然而，其在阻塞性睡眠呼吸暂停（OSA）引起的心脏损伤中的功能尚不清楚。本研究旨在确定 miR-146a-5p 在间歇性低氧（IH）诱导的心肌损伤中的作用及其潜在的分子机制。我们将 H9c2 细胞暴露于 IH 条件下；通过 RT-qPCR 检测 miR-146a-5p 的表达水平。通过细胞计数试剂盒-8（CCK-8）、流式细胞术和 Western blot 分别评估细胞活力、细胞凋亡以及凋亡相关蛋白的表达。通过双荧光素酶报告基因实验证实 miR-146a-5p 的靶基因。IH 显著降低了细胞活力，但增强了细胞凋亡。同时，IH 后 H9c2 细胞中 miR-146a-5p 的表达水平增加。后续实验表明，通过 miR-146a-5p 沉默可减轻 IH 诱导的损伤。通过生物信息学分析预测 X 连锁凋亡抑制蛋白（XIAP）是 miR-146a-5p 的直接靶基因，并进一步得到证实。令人惊讶的是，IH 下 miR-146a-5p 抑制的作用可通过下调 XIAP 表达而逆转。总之，我们的研究结果表明，miR-146a-5p 可通过靶向 XIAP 来减弱 H9c2 的活力并促进其凋亡，从而加重 IH 诱导的 H9c2 细胞损伤，这可以增强我们对 OSA 相关心脏损伤机制的理解。
