Abstract

Ambient air pollution is a leading cause of non-communicable disease in the world. PM_2.5 has the potential to change the miRNAs profiles, which in turn causes cardiovascular effects. Hypoxia-inducible factor (HIF)-1 plays a critical role in the development of atherosclerosis. Yet, the possible role of miR-939-5p/HIF-1α in PM_2.5-induced endothelial injury remains elusive. Therefore, the study aims to investigate the effects of miR-939-5p and HIF-1α on PM_2.5-triggered endothelial injury. The results from immunofluorescence, qRT-PCR, LSCM, and western blot assays demonstrated that PM_2.5 increased the levels of HIF-1α, inflammation and apoptosis in human aortic endothelial cells (HAECs). Yet, the inflammatory response and mitochondrial-mediated apoptosis pathway were effectively inhibited in HIF-1α knockdown HAECs lines. The expression of miR-939-5p was significantly down-regulated in HAECs after exposed to PM_2.5. The luciferase reporter, qRT-PCR and western blot results demonstrated that miR-939-5p could directly targeted HIF-1α. And the miR-939-5p overexpression restricted PM_2.5-triggered decreases in cell viability and increases in lactic dehydrogenase (LDH) activity, reactive oxygen species (ROS), mitochondrial membrane potential (MMP) and inflammation. In addition, miR-939-5p overexpression remarkably suppressed PM_2.5-triggered BcL-2/Bax ratio reduction and Cytochrome C, Cleaved Caspase-9 and Cleaved Caspase-3 expression increase, revealed that miR-939-5p hampered PM_2.5-induced endothelial apoptosis through mitochondrial-mediated apoptosis pathway. Our results demonstrated that PM_2.5 increased the expression of HIF-1α followed by a pro-inflammatory and apoptotic response in HAECs. The protective effect of miR-939-5p on PM_2.5-triggered endothelial cell injury by negatively regulating HIF-1α. miR-939-5p might present a new therapeutic target for PM_2.5 induced endothelial injury.

摘要

环境空气污染是世界上非传染性疾病的主要原因。PM _2.5有可能改变 miRNA 谱，进而导致心血管影响。缺氧诱导因子 (HIF)-1 在动脉粥样硬化的发展中起关键作用。然而，miR-939-5p/HIF-1α 在 PM _2.5诱导的内皮损伤中的可能作用仍然难以捉摸。因此，本研究旨在研究 miR-939-5p 和 HIF-1α 对 PM _2.5引发的内皮损伤的影响。免疫荧光、qRT-PCR、LSCM 和蛋白质印迹分析的结果表明 PM _2.5增加人主动脉内皮细胞 (HAEC) 的 HIF-1α、炎症和凋亡水平。然而，在 HIF-1α 敲低的 HAECs 系中，炎症反应和线粒体介导的细胞凋亡途径被有效抑制。暴露于 PM _2.5后，HAEC 中 miR-939-5p 的表达显着下调。荧光素酶报告基因、qRT-PCR 和蛋白质印迹结果表明 miR-939-5p 可以直接靶向 HIF-1α。并且 miR-939-5p 过表达限制了 PM _2.5引发的细胞活力降低和乳酸脱氢酶 (LDH) 活性、活性氧 (ROS)、线粒体膜电位 (MMP) 和炎症的增加。此外，miR-939-5p 过表达显着抑制 PM _2.5-触发的 BcL-2/Bax 比率降低和细胞色素 C、Cleaved Caspase-9 和 Cleaved Caspase-3 表达增加，表明 miR-939-5p通过线粒体介导的细胞凋亡途径阻碍 PM _2.5诱导的内皮细胞凋亡。我们的结果表明，PM _2.5增加了 HIF-1α 的表达，随后是 HAEC 中的促炎和凋亡反应。miR-939-5p通过负调节 HIF-1α对 PM _2.5引发的内皮细胞损伤的保护作用。miR-939-5p 可能为 PM _2.5诱导的内皮损伤提供新的治疗靶点。