MicroRNA let-7g inhibited hypoxia-induced proliferation of PASMCs via G(0)/G(1) cell cycle arrest by targeting c-myc
MicroRNA let-7g inhibited hypoxia-induced proliferation of PASMCs via G(0)/G(1) cell cycle arrest by targeting c-myc
复制标题
MicroRNA let-7g 通过靶向 c-myc 通过 G(0)/G(1) 细胞周期阻滞抑制缺氧诱导的 PASMC 增殖
DOI：
10.1016/j.lfs.2016.11.020
复制
发表时间：
2017
期刊：
影响因子：
6.1
通讯作者：
Cheng Xiao-Shu
中科院分区：
文献类型：
--
作者：
Zhang Wei-Fang;Xiong You-Wen;Zhu Tian-Tian;Xiong Ai-Zhen;Bao Hui-hui;Cheng Xiao-Shu
目的肺动脉高压(PH)是一种以肺内血管平滑肌细胞增殖增强、凋亡抑制为特征的增生性疾病。最近，基于网络的生物信息学已经发现了let-7家族，它是一种肿瘤抑制微RNA，调节着与PH相关的多个相互作用的靶点。然而，LET-7在PH患者血管内稳态中的作用仍不清楚。因此，我们想探讨let-7在低氧诱导的PASMCs增殖中的作用及其在缺氧性肺动脉高压(HPH)中的作用机制。主要方法：雄性SD大鼠暴露于低氧(10%O2)中21天，诱导HPH。采用实时定量聚合酶链式反应(qRT-PCR)和原位杂交技术检测LET-7的表达。原代培养大鼠PASMCs暴露于低氧(3%O2)。用MTS和EDU检测PASMCs的增殖情况。用qRT-PCR和Western blotting分别检测c-myc、Bmi-1和p16的mRNA和蛋白表达。结果：在LET-7家族成员中，只有LET-7b和LET-7g在重塑的HPH大鼠的肺动脉中表达显著下调。此外，缺氧性PASMCs仅LET-7g水平降低。低氧或LET-7G抑制剂均可刺激PASMCs增殖，而LET-7G模拟抑制低氧诱导的PASMCs增殖。C-myc是PASMCs中let-7g的靶点。转染let-7g模拟物可抑制缺氧诱导的c-myc、Bmi-1上调和p16下调，最终控制细胞周期进程。
AimsPulmonary hypertension (PH) is a proliferative disorder characterized by enhanced proliferation and suppressed apoptosis of intrapulmonary vascular smooth muscle cells. Recently, network-based bioinformatics have identified let-7 family, a tumor suppressive microRNA, regulate multiple interacting targets relevant to PH. However, the role of let-7 in vascular homeostasis in PH remains unknown. Thus, we wanted to investigate the role of let-7 in hypoxia-induced PASMCs proliferation and the underlying mechanism in hypoxic pulmonary hypertension (HPH).Main methodsThe male Sprague–Dawley (SD) rats were exposed to hypoxia (10% O2) for 21 days to induce HPH. The expression of let-7 was determined by quantitative real-time polymerase chain reaction (qRT-PCR) and in situ hybridization. Primary rat PASMCs were exposed to hypoxia (3% O2). MTS and EDU were performed to evaluate PASMCs proliferation. The mRNA and protein expression of c-myc, Bmi-1 and p16 were determined by qRT-PCR and Western blotting, respectively. The functions of let-7g on PASMCs proliferation, c-myc, Bmi-1 and p16 expression were assessed by let-7g mimic and inhibitor transfection.Key findingsAmong let-7 family members, only let-7b and let-7g were significantly down-regulated in remodeled pulmonary artery in HPH rats. Furthermore, only let-7g level was decreased in hypoxic PASMCs. Either hypoxia or let-7g inhibitor stimulated proliferation of PASMCs, let-7g mimic inhibited hypoxia-induced PASMCs proliferation. C-myc was the target of let-7g in PASMCs. Transfect of let-7g mimic inhibited hypoxia-induced c-myc, Bmi-1 up-regulation and p16 down-regulation, which ultimately controls cell cycle progression.SignificanceLoss of inhibition on c-myc-Bmi-1-p16 signaling pathway by let-7g may lead to PASMCs proliferation and vascular remodeling in HPH.