Yu Xiufeng, Li Tingting, Liu Xia, Yu Hao, Hao Zhongfei, Chen Yingli, Zhang Chen, Liu Yumei, Li Qian, Mao Min, Zhu Daling
Department of Biopharmaceutical Sciences, College of Pharmacy, Harbin Medical University (Daqing), Daqing, China.
Cell Physiol Biochem. 2015;35(6):2079-97. doi: 10.1159/000374015. Epub 2015 Apr 7.
We have previously shown that 15-hydroxyeicosatetraenoic acid (15-HETE) plays a critical role in pulmonary hypertension (PH)-associated vascular remodeling. However, the signaling mechanisms remain unclear. The purpose of this study was to investigate the role of 15-lipoxygenase-2 (15-LO-2)/15-HETE-mitogen-activated protein kinases (MAPKs) pathway in hypoxia-induced pulmonary vascular remodeling and the underlying mechanisms.
The arterial wall thickness was measured by hematoxylin and eosin (HE) staining in distal pulmonary arteries isolated from normal and PAH patient-derived lungs. The protein expression of phosphorylated extracellular signal-regulated kinase (p-ERK) and phosphorylated p38 mitogen-activated protein kinases (p-p38MAPK) were measured by Western blot in the lungs of PAH patients and hypoxia-induced rats. The apoptosis of cultured rat pulmonary arterial smooth muscle cells (PASMCs) was determined by Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and Flow cytometry. The cell proliferation and cell cycle in PASMCs following hypoxia were analyzed by bromodeoxyuridine incorporation and flow cytometry, respectively.
Our results showed that the levels of p-ERK and p-p38MAPK were both drastically elevated in lungs from human patients and hypoxic rats. The HE staining revealed that the medial wall thickness was higher in patients with PAH than normal humans. In cultured PASMCs, Hypoxia stimulated the cell proliferation, the cell cycle progression, and subsequently promoted cell differentiation and cell migration leading to the suppressed cell apoptosis. Furthermore, MAPKs- induced cell proliferation and anti-apoptosis in PASMCs is 15-LO-2/15HETE activation-dependent.
Our study indicates that hypoxia-induced pulmonary vascular remodeling is associated with increased levels of 15-LO-2 and 15-HETE. 15-LO-2/15-HETE stimulates the cell proliferation and anti-apoptosis in PASMCs through phosphorylation of ERK and p38MAPK, which subsequently contributing to hypoxia-induced pulmonary vascular remodeling.
我们之前已经表明，15-羟基二十碳四烯酸（15-HETE）在肺动脉高压（PH）相关的血管重塑中起关键作用。然而，其信号传导机制仍不清楚。本研究的目的是探讨15-脂氧合酶-2（15-LO-2）/15-HETE-丝裂原活化蛋白激酶（MAPKs）通路在缺氧诱导的肺血管重塑中的作用及潜在机制。
通过苏木精和伊红（HE）染色测量从正常和PAH患者来源的肺中分离出的远端肺动脉的动脉壁厚度。通过蛋白质印迹法检测PAH患者和缺氧诱导大鼠肺中磷酸化细胞外信号调节激酶（p-ERK）和磷酸化p38丝裂原活化蛋白激酶（p-p38MAPK）的蛋白表达。通过末端脱氧核苷酸转移酶dUTP缺口末端标记（TUNEL）和流式细胞术测定培养的大鼠肺动脉平滑肌细胞（PASMCs）的凋亡。分别通过溴脱氧尿苷掺入和流式细胞术分析缺氧后PASMCs中的细胞增殖和细胞周期。
我们的结果表明，人类患者和缺氧大鼠肺中的p-ERK和p-p38MAPK水平均显著升高。HE染色显示，PAH患者的中膜厚度高于正常人。在培养的PASMCs中，缺氧刺激细胞增殖、细胞周期进程，随后促进细胞分化和细胞迁移，导致细胞凋亡受抑制。此外，MAPKs诱导的PASMCs细胞增殖和抗凋亡是15-LO-2/15HETE激活依赖性的。
我们的研究表明，缺氧诱导的肺血管重塑与15-LO-2和15-HETE水平升高有关。15-LO-2/15-HETE通过ERK和p38MAPK的磷酸化刺激PASMCs中的细胞增殖和抗凋亡，这随后导致缺氧诱导的肺血管重塑。
