Baicalin promotes apoptosis and inhibits proliferation and migration of hypoxia-induced pulmonary artery smooth muscle cells by up-regulating A2a receptor via the SDF-1/CXCR4 signaling pathway
Baicalin promotes apoptosis and inhibits proliferation and migration of hypoxia-induced pulmonary artery smooth muscle cells by up-regulating A2a receptor via the SDF-1/CXCR4 signaling pathway
复制标题
DOI：
10.1186/s12906-018-2364-9
复制
发表时间：
2018-12-12
影响因子：
--
通讯作者：
Wang, Liangxing
中科院分区：
文献类型：
--
作者：
Huang, Xiaoying;Mao, Wei;Wang, Liangxing
黄芩苷是一种黄酮类化合物，对缺氧诱导的肺动脉平滑肌细胞（PASMCs）的增殖、迁移和凋亡抵抗具有特殊的药理作用。然而，其潜在机制尚未完全阐明。虽然我们之前的研究表明A2aR的激活会减弱CXCR的表达，但在缺氧pasmc中，A2aR与SDF-1/CXCR4轴之间的关系知之甚少。本研究旨在探讨A2aR对缺氧PASMCs中SDF-1/CXCR4轴的影响及其机制，以及黄芩苷是否通过A2aR发挥其保护作用。方法将大鼠PASMCs在常氧/缺氧条件下培养，分为常氧、缺氧、缺氧+ AMD3100 （CXCR4拮抗剂）、缺氧+黄芩苷、缺氧+阴性病毒、常氧+ A2aR敲低、缺氧+ A2aR激动剂CGS21680、缺氧+ A2aR敲低+黄芩苷9组。采用慢病毒转染方法建立PASMCs A2aR敲低模型。细胞在缺氧条件下孵育24h。采用RT-qPCR和western blot检测A2aR、SDF-1和CXCR4的表达水平。CCK-8法和Transwell法观察细胞增殖和迁移率。采用流式细胞术（FCM）和原位细胞死亡检测试剂盒（荧光素）检测细胞周期分布和细胞凋亡。结果低氧条件下，A2aR、SDF-1和CXCR4水平较常氧条件下显著升高。黄芩苷干预组中，A2aR上调时SDF-1和CXCR4被抑制的趋势更为明显。黄芩苷直接增强A2aR表达，而A2aR敲低则削弱黄芩苷的功能。缺氧+ A2aR敲低组SDF-1和CXCR4表达水平升高，PASMCs的增殖和迁移率升高，凋亡率降低。黄芩苷与CGS21680作用相反。结论黄芩苷通过上调A2aR和下调SDF-1/CXCR4轴，有效抑制缺氧诱导的PASMC增殖、迁移、凋亡抵抗及SDF-1分泌。
BackgroundBaicalin is a flavonoid compound that exerts specific pharmacological effect in attenuating the proliferation, migration, and apoptotic resistance of hypoxia-induced pulmonary artery smooth muscle cells (PASMCs). However, the underlying mechanism has not been fully elucidated yet. Although our previous studies had indicated that activation of A2aR attenuates CXCR expression, little is known about the relationship between A2aR and SDF-1/CXCR4 axis in hypoxic PASMCs. In this study, we aimed to investigate the effect of A2aR on the SDF-1/CXCR4 axis in hypoxic PASMCs, the mechanism underlying this effect, and whether baicalin exerts its protective functions though A2aR.MethodsRat PASMCs were cultured under normoxia/hypoxia and divided into nine groups: normoxia, hypoxia, hypoxia + AMD3100 (a CXCR4 antagonist), hypoxia + baicalin, hypoxia + negative virus, normoxia + A2aR knockdown, hypoxia + A2aR knockdown, hypoxia + CGS21680 (an A2aR agonist), and hypoxia + A2aR knockdown + baicalin. Lentiviral transfection methods were used to establish the A2aR knockdown model in PASMCs. Cells were incubated under hypoxic conditions for 24h. Expression levels of A2aR, SDF-1, and CXCR4 were detected using RT-qPCR and western blot. The proliferation and migration rate were observed via CCK-8 and Transwell methods. Cell cycle distribution and cell apoptosis were measured by flow cytometry (FCM) and the In-Situ Cell Death Detection kit (Fluorescein).ResultsUnder hypoxic conditions, levels of A2aR, SDF-1, and CXCR4 were significantly increased compared to those under normoxia. The trend of SDF-1 and CXCR4 being inhibited when A2aR is up-regulated was more obvious in the baicalin intervention group. Baicalin directly enhanced A2aR expression, and A2aR knockdown weakened the function of baicalin. SDF-1 and CXCR4 expression levels were increased in the hypoxia + A2aR knockdown group, as were the proliferation and migration rates of PASMCs, while the apoptotic rate was decreased. Baicalin and CGS21680 showed opposite effects.ConclusionsOur data indicate that baicalin efficiently attenuates hypoxia-induced PASMC proliferation, migration, and apoptotic resistance, as well as SDF-1 secretion, by up-regulating A2aR and down-regulating the SDF-1/CXCR4 axis.