微小RNA let-7g与凝集素样氧化低密度脂蛋白受体1（LOX-1）之间的负反馈调节介导缺氧诱导的肺动脉平滑肌细胞增殖。
Negative feedback regulation between microRNA let-7g and LOX-1 mediated hypoxia-induced PASMCs proliferation.
作者信息
Zhang Wei-Fang, Zhu Tian-Tian, Xiong You-Wen, Xiong Ai-Zhen, Ge Xiao-Yue, Hu Chang-Ping, Zhang Zheng
机构信息
Department of Pharmacology, Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, 410078, China; Department of Pharmacy, The Second Affiliated Hospital of Nanchang University, Nanchang, 330006, China.
Department of Pharmacology, Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, 410078, China; Hunan Provincial Key Laboratory of Cardiovascular Research, Central South University, Changsha, Hunan, 410078, China.
出版信息
Biochem Biophys Res Commun. 2017 Jul 8;488(4):655-663. doi: 10.1016/j.bbrc.2017.01.073. Epub 2017 Jan 18.
BACKGROUND
Pulmonary hypertension (PH) is a proliferative disorder associated with enhanced proliferation and suppressed apoptosis of pulmonary artery smooth muscle cells (PASMCs). Our lately study demonstrated that let-7g inhibited hypoxia-induced proliferation of PASMCs via repressing c-myc-Bmi-1-p16 signaling pathway. However, the upstream of let-7g has not yet been fully defined. Previous studies have shown that LOX-1, a target of let-7g, could also regulate the expression of let-7g in human aortic endothelial cells. In this present study, we aimed to investigate whether there is a negative feedback regulation between microRNA let-7g and LOX-1 in hypoxia-induced proliferation of PASMCs.
METHODS
SD Rats were exposed to hypoxia (10% O, 3 weeks) to induce PH. HE staining was used to evaluate pulmonary artery remodeling. in situ hybridization and immunohistochemistry were performed to assess the expression and distribution of let-7g and LOX-1, respectively. MTS, EDU and flow cytometry were performed to evaluate PASMCs proliferation. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting were conducted to assess the expression of let-7g, LOX-1, calpain-1,-2,-4, and OCT-1.
RESULTS
The expression of let-7g was significantly down-regulated in pulmonary arteries of hypoxia-induced PH rats accompanied by pulmonary vascular remodeling, whereas let-7g mimic inhibited hypoxia-induced proliferation of PASMCs and up-regulation of LOX-1 expression. LOX-1 blocking reversed hypoxia-induced down-regulation of let-7g expression. Calpains, protein kinase C and OCT-1 were involved in negative feedback regulation between let-7g and LOX-1.
CONCLUSION
Negative feedback regulation between let-7g and LOX-1 mediated hypoxia-induced proliferation of in PASMCs.
背景
肺动脉高压（PH）是一种增殖性疾病，与肺动脉平滑肌细胞（PASMCs）增殖增强和凋亡受抑制有关。我们最近的研究表明，let-7g通过抑制c-myc-Bmi-1-p16信号通路来抑制缺氧诱导的PASMCs增殖。然而，let-7g的上游机制尚未完全明确。先前的研究表明，let-7g的靶标LOX-1也可调节人主动脉内皮细胞中let-7g的表达。在本研究中，我们旨在探讨在缺氧诱导的PASMCs增殖过程中，微小RNA let-7g与LOX-1之间是否存在负反馈调节。
方法
将SD大鼠暴露于低氧环境（10% O₂，3周）以诱导PH。采用苏木精-伊红（HE）染色评估肺动脉重塑。分别进行原位杂交和免疫组织化学检测来评估let-7g和LOX-1的表达及分布。采用甲基噻唑基四唑（MTS）、5-乙炔基-2'-脱氧尿苷（EDU）和流式细胞术评估PASMCs增殖。进行定量实时聚合酶链反应（qRT-PCR）和蛋白质免疫印迹法检测let-7g、LOX-1、钙蛋白酶-1、-2、-4和八聚体转录因子1（OCT-1）的表达。
结果
在缺氧诱导的PH大鼠肺动脉中，let-7g的表达显著下调，同时伴有肺血管重塑，而let-7g模拟物可抑制缺氧诱导的PASMCs增殖及LOX-1表达上调。阻断LOX-1可逆转缺氧诱导的let-7g表达下调。钙蛋白酶、蛋白激酶C和OCT-1参与了let-7g与LOX-1之间的负反馈调节。
结论
let-7g与LOX-1之间的负反馈调节介导了缺氧诱导的PASMCs增殖。
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