Department of Orthopedics, The Second Xiangya Hospital of Central South University, Changsha 410011, Hunan, People's Republic of China.
J Biosci. 2021;46.
Hypoxia plays an important role in many heart diseases. MicroRNA-9 (miR-9) has been reported to be involved in hypoxia-induced cell proliferation, injury and apoptosis in cardiomyocytes. However, the underlying mechanism still remains poorly understood. The expression levels of miR-9 and cyclin-dependent kinase 8 (CDK8) were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The relative protein expression was measured by Western blot. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT), lactate dehydrogenase (LDH) measurement, flow cytometry assays were conducted to detect cell proliferation, the release of LDH and cell apoptosis, respectively. The potential relationship between miR-9 and CDK8 was predicted by online database, and confirmed by dual-luciferase reporter assay. We found that miR-9 was increased, while CDK8 was decreased in hypoxia-treated H9c2 cells. miR-9 down-regulation or CDK8 up-regulation promoted cell proliferation, while repressed cell damage and apoptosis in hypoxia-induced H9c2 cells. Moreover, CDK8 was identified to be target of miR-9, and CDK8 knockdown could reverse the effects of miR-9 inhibitor on cell proliferation, damage and apoptosis in hypoxia-treated H9c2 cells. Besides, miR-9 could regulate the Wnt/b-catenin pathway by targeting CDK8 in hypoxic-induced H9c2 cells. In conclusion, miR-9 repressed cell proliferation and promoted cell damage and apoptosis by binding to CDK8 through the Wnt/ β-catenin pathway in hypoxic-induced H9c2 cells, which provided a new direction for further studying the treatment of hypoxia-aroused heart diseases.
缺氧在许多心脏疾病中起着重要作用。已经有报道称 microRNA-9（miR-9）参与了心肌细胞缺氧诱导的增殖、损伤和凋亡。然而，其潜在机制仍知之甚少。通过实时定量聚合酶链反应（qRT-PCR）检测 miR-9 和细胞周期蛋白依赖性激酶 8（CDK8）的表达水平。通过 Western blot 测定相对蛋白表达水平。通过 3-(4,5-二甲基-2-噻唑基)-2,5-二苯基-2H-四唑溴盐（MTT）、乳酸脱氢酶（LDH）测量、流式细胞术检测细胞增殖、LDH 的释放和细胞凋亡。通过在线数据库预测 miR-9 和 CDK8 之间的潜在关系，并通过双荧光素酶报告基因实验进行验证。我们发现缺氧处理的 H9c2 细胞中 miR-9 增加，而 CDK8 减少。miR-9 下调或 CDK8 上调促进细胞增殖，而抑制缺氧诱导的 H9c2 细胞损伤和凋亡。此外，CDK8 被鉴定为 miR-9 的靶基因，CDK8 敲低可以逆转 miR-9 抑制剂对缺氧处理的 H9c2 细胞增殖、损伤和凋亡的影响。此外，miR-9 可以通过靶向 CDK8 调节缺氧诱导的 H9c2 细胞中的 Wnt/β-catenin 通路。总之，miR-9 通过 Wnt/β-catenin 通路与 CDK8 结合，抑制细胞增殖，促进细胞损伤和凋亡，为进一步研究缺氧引起的心脏疾病的治疗提供了新的方向。
