HIF-1α/SDF-1信号轴在低氧诱导祖细胞迁移和黏附中的作用

Effects of HIF-1α/SDF-1 signaling axis on hypoxia-induced migration and adhesion of progenitor cells

目的:分析低氧对大鼠肺动脉内皮细胞低氧诱导因子(HIF-1α)及间质细胞衍生因子(SDF-1)表达的影响,探讨二者的相互关系(即是否存在HIF-1α/SDF-1信号轴)及其在低氧诱导祖细胞迁移和黏附中的作用。方法:免疫磁珠分离纯化SD大鼠外周血CD34/CXCR4阳性祖细胞,免疫荧光、Western blotting及ELISA法检测不同低氧时间HIF-1α和SDF-1在大鼠肺动脉内皮细胞的表达,迁移和黏附实验检测常氧组、低氧组、HIF-1α抑制剂2-甲氧雌二醇(2ME2)组、SDF-1中和抗体组及同时加2ME2和SDF-1中和抗体组祖细胞的迁移指数和黏附率。结果:HIF-1α和SDF-1的表达与低氧时间有关,低氧12h时二者表达到峰值(均P<0.01),应用2ME2可使SDF-1表达下调(P<0.05),应用2ME2或SDF-1中和抗体后均下调祖细胞的迁移指数和黏附率(P<0.05)。结论:低氧可诱导肺动脉内皮细胞HIF-1α及受其调控的下游因子SDF-1的表达,提示HIF-1α与SDF-1存在信号调节关系。HIF-1α/SDF-1信号轴在介导祖细胞迁移和黏附至肺动脉内皮细胞的过程中起重要作用。

AIM： To observe the expression of hypoxia-inducible factor-1alpha （HIF-1α） and stromal cell-derived factor 1 （SDF-1） in pulmonary artery endothelial cells （PAECs） of SD rats and to investigate the role of HIF-1α/SDF-1 signaling axis on hypoxia-induced migration and adhesion of progenitor cells to PAECs. METHODS： Immunomagnetic beads were used to separate and purify the CD34＋/CXCR4＋ progenitor cells derived from the peripheral circulation of SD rats. The expression of HIF-1α and SDF-1 in PAECs exposed to hypoxia （1% O2, 5% CO2 and 94% N2） was detected by immunofluorescence, Western blotting and ELISA. The migration index and adhesion rate were measured in the progenitor cells, which were subjected to the following different treatments： （1） normoxia （21% O2）; （2） hypoxia 12 h; （3） hypoxia 12 h ＋HIF-1α inhibitor （2ME2）; （4） hypoxia 12 h＋SDF-1 neutralizing antibody; （5） hypoxia 12 h＋2ME2＋SDF-1 neutralizing antibody.RESULTS： The expression of HIF-1α and SDF-1 in PAECs was effectively induced by the hypoxic exposure, and both of them reached the peak levels after 12 h of hypoxic treatment （P〈0.01）, while administration of 2ME2 decreased the hypoxia-induced SDF-1 expression （P〈0.05）. Treatment of the PAECs with 2ME2 or SDF-1 neutralizing antibody attenuated the migration index and adhesion rate of progenitor cells to the PAECs （P〈0.05）. CONCLUSION： There is a HIF-1α/SDF-1 signaling axis in hypoxia-exposed PAECs, which may play a crucial role in the migration and adhesion of progenitor cells to PAECs.