Department of Cardiology, Jiangxi Provincial People's Hospital Affiliated to Nanchang University, Nanchang, Jiangxi, China.
Department of Gerontology, The First Affliated Hospital of Nanchang University, Nanchang, Jiangxi, China.
J Cardiovasc Pharmacol. 2021 Feb 1;77(2):200-207. doi: 10.1097/FJC.0000000000000949.
Hypoxia leads to insufficient supply of blood and nutrients, which is major incentive for cardiomyocyte injury and apoptosis. Previous studies reported the regulation effects of microRNAs (miRNAs) in myocardial infarction, whereas function and molecular mechanisms of miR-322-5p were still unclear. Therefore, our study focused on the biological role of miR-322-5p in hypoxia-induced cardiac myoblast cells apoptosis and injury. The expression levels of miR-322-5p and cytokine-induced apoptosis inhibitor 1 (CIAPIN1) were measured by real-time quantitative polymerase chain reaction in cardiac myoblast cells. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazol-3-ium bromide (MTT), lactic dehydrogenase, and flow cytometry assays were performed to examine proliferation, injury, and apoptosis of cardiac myoblast cells, respectively. The protein expression levels were evaluated with western blot assay. The relationship between miR-322-5p and CIAPIN1 was confirmed by dual-luciferase reporter analysis. We found that miR-322-5p level was increased in cardiac myoblast cells exposed to hypoxia. In addition, miR-322-5p silencing could weaken injury and apoptosis in cardiac myoblast cells induced by hypoxia; meanwhile, inhibition of miR-322-5p activation of phosphatidylinositol-3 kinases (PI3K)/protein kinase B (AKT) signal pathway. Besides, CIAPIN1 was a target mRNA of miR-322-5p based on bioinformatics prediction. CIAPIN1 knockdown reversed the effects of miR-322-5p silencing on hypoxic cardiac myoblast cells. Suppression of miR-322-5p protected cardiac myoblast cells against hypoxia-induced injury and apoptosis through regulation of CIAPIN1 expression and PI3K/AKT signal pathway.
缺氧导致血液和营养供应不足，这是心肌细胞损伤和凋亡的主要诱因。先前的研究报道了 microRNAs (miRNAs) 在心肌梗死中的调节作用，然而 miR-322-5p 的功能和分子机制仍不清楚。因此，我们的研究集中在 miR-322-5p 在缺氧诱导的心肌细胞凋亡和损伤中的生物学作用。通过实时定量聚合酶链反应测量心肌细胞中 miR-322-5p 和细胞因子诱导的凋亡抑制剂 1 (CIAPIN1) 的表达水平。通过 3-(4,5-二甲基噻唑-2-基)-2,5-二苯基-2H-四唑溴盐 (MTT)、乳酸脱氢酶和流式细胞术检测分别评估心肌细胞的增殖、损伤和凋亡。通过 Western blot 检测评估蛋白表达水平。通过双荧光素酶报告分析证实了 miR-322-5p 和 CIAPIN1 之间的关系。我们发现，缺氧暴露的心肌细胞中 miR-322-5p 水平增加。此外，miR-322-5p 沉默可减弱缺氧诱导的心肌细胞损伤和凋亡；同时，抑制 miR-322-5p 激活磷脂酰肌醇-3 激酶 (PI3K)/蛋白激酶 B (AKT) 信号通路。此外，基于生物信息学预测，CIAPIN1 是 miR-322-5p 的靶 mRNA。CIAPIN1 敲低逆转了 miR-322-5p 沉默对缺氧心肌细胞的影响。抑制 miR-322-5p 通过调节 CIAPIN1 表达和 PI3K/AKT 信号通路保护心肌细胞免受缺氧诱导的损伤和凋亡。
