EP_2A体外可促进人CD34~+细胞归巢而不能促进其增殖

目的:探讨前列腺素E_2受体2激动剂(EP_2A)在体外对人CD34~+细胞的归巢与增殖作用。方法:收集健康供者经粒细胞集落刺激因子动员后的外周血,免疫磁珠法分选出人CD34~+细胞;同时收集健康供者动员前骨髓液,分离单个核细胞,并行骨髓间充质干细胞(BMMSC)培养。人CD34~+细胞和BMMSC经前列腺素E_2(阳性对照)、DMSO(阴性对照)、EP_2A和EP_2A+前列腺素E_2受体2拮抗剂(EP_2AA)处理后,对人CD34~+细胞用CCK-8法检测细胞活力,集落形成实验检测集落形成数目,流式细胞术检测G_2/M期细胞比例,Western blot检测细胞中survivin、β-catenin及CXC趋化因子受体4(CXCR4)的蛋白表达;ELISA法检测BMMSC中基质细胞衍生因子1α(SDF-1α)的含量。结果:EP_2A组与阴性对照组相比,人CD34~+细胞在细胞活力、集落形成数目、G_2/M期比例及survivin和β-catenin蛋白表达方面均无明显差别。但EP_2A组人CD34~+细胞CXCR4及BMMSC SDF-1α的表达均明显高于阴性对照组。结论:EP_2A体外可促进人CD34~+细胞归巢但不能促进其增殖。

EP2A promotes human CD34+ cell homing in vitro but not proliferation

AIM: To investigate the role of prostaglandin E₂ receptor 2 agonist (EP₂A) in proliferation and homing of human CD34⁺ cells. METHODS: Bone marrow fluid and peripheral blood containing stem cells were collected from healthy donors mobilized by granulocyte colony-stimulating factor in our department. Human CD34⁺ cells were isolated by the method of magnetic-activated cell sorting microbeads. Bone marrow mononuclear cells were isolated by Ficoll-Paque centrifugation, and the bone marrow mesenchymal stem cells (BMMSC) were cultured with L-DMEM. Human CD34⁺ cells and BMMSC were divided into 4 groups, and treated with PGE₂ (as positive control), DMSO (as negative control), EP₂A and EP₂A+prostaglandin E₂ receptor 2 antagonist (EP₂AA), respectively. After exposed to the reagents, human CD34⁺ cell viability was measured by CCK-8 assay, the number of colonies was evaluated by colony-formation assay, the cell cycle distribution was analyzed by flow cytometry, and the protein expression of survivin, β-catenin and CXC chemokine receptor 4 (CXCR4) was detrmined by Western blot. Moreover, the concentration of stromal cell-derived factor-1α (SDF-1α) in the BMMSC was detected by ELISA. RESULTS: The cell viability and the colony number of human CD34⁺ cells in EP₂A group were not higher than those in negative control group. Furthermore, the proportion of human CD34⁺ cells treated with EP₂A in G₂/M phase was not elevated compared with negative control group. The protein expression of survivin and β-catenin did not up-regulated in human CD34⁺ cells exposed to EP₂A, but the protein expression of CXCR4 in human CD34⁺ cells and the concentration of SDF-1α in BMMSC were elevated. CONCLUSION: EP₂A promotes human CD34⁺ cell homing in vitro but not proliferation.