质子感知受体OGR1介导酸化环境对内皮祖细胞活力和成管作用的影响

Proton-sensing receptor OGR1 mediates inhibitory effects of acidic environment on viability and tube formation ability of endothelial progenitor cells

目的:分析卵巢癌G蛋白偶联受体1(ovarian cancer G-protein-coupled receptor 1, OGR1)在内皮祖细胞(endothelial progenitor cells,EPCs)中的表达,探索OGR1的酸调节效应对内皮祖细胞活力和成管能力的影响。方法:体外分离和培养小鼠骨髓源性内皮祖细胞,采取 FITC-UEA-I 和 DiI-Ac-LDL 双荧光染色法鉴定,利用real-time PCR和Western blot检测OGR1在小鼠EPCs的表达。采用不同pH值培养基处理EPCs后分析OGR1表达。以小干扰RNA(siRNA)沉默 OGR1 ,使用CCK-8实验和流式细胞术分析EPCs的活力及周期分布的变化,划痕实验、Transwell迁移实验以及成管实验分析EPCs的迁移能力和成管作用的变化。结果:分离诱导的EPCs分化良好,FITC-UEA-I 及 DiI-Ac-LDL染色均呈阳性,小鼠内皮祖细胞存在OGR1的mRNA及蛋白表达。随着培养基pH值降低,OGR1表达逐渐升高,在pH 6.4的培养基中OGR1表达最高( P <0.05)。pH 6.4培养基抑制EPCs的活力并导致其生长停滞,而使用siRNA沉默 OGR1 后可部分逆转酸化环境对EPCs的作用( P <0.05)。pH 6.4培养基抑制EPCs的迁移和成管能力,而使用siRNA沉默 OGR1 后可部分逆转酸化环境对EPCs的作用( P <0.05)。结论: OGR1在EPCs中呈阳性表达,并介导了酸化环境对EPCs活力及迁移和成管能力的抑制作用。

AIM: To analyze the expression of ovarian cancer G-protein-coupled receptor 1 (OGR1), a proton-sensing receptor, in the endothelial progenitor cells (EPCs), and to explore the role of OGR1 in acid-regulated viability and tube formation ability of EPCs. METHODS: The method of FITC-UEA-I and DiI-Ac-LDL double staining was used to identify the EPCs. The expression of OGR1 in mouse EPCs was analyzed by real-time-PCR and Western blot. After treatment with different pH media, the OGR1 expression was analyzed in EPCs. The viability and cell cycle distribution of the EPCs were analyzed by CCK-8 and flow cytometry assay. The migration and vascularization of EPCs were measured by scratch test, Transwell migration assay and tube formation experiments after silencing OGR1 using small interfering RNA(siRNA). RESULTS: The isolated endothelial progenitor cells were well differentiated, and FITC-UEA-I and DiI-Ac-LDL staining was positive. The expression of OGR1 at mRNA and protein levels was observed in mouse EPCs. The expression of OGR1 was increased gradually with the decrease of pH value of the medium, while the expression of OGR1 was the highest in the medium of pH 6.4 ( P <0.05). pH 6.4 medium inhibited the viability of the EPCs and induced cell cycle arrest at G 0/G 1 phase. Knock-down of OGR1 expression by siRNA partially reversed the effect of acidic environment on the EPCs ( P <0.05). The abilities of migration and tube formation of EPCs were inhibited by pH 6.4 medium, while transfection of siRNA to silence OGR1 expression partially reversed the effect ( P <0.05). CONCLUSION: The expression of OGR1 in EPCs is positive, and OGR1 mediates the effects of acid on the viability, migration and tube formation ability of EPCs.