LY294002可抑制VEGF和PlGF调控小鼠胎肝造血干细胞髓系分化的作用

 【目的】探讨内皮生长因子（VEGF）和胎盘生长因子（PlGF）对小鼠胎肝造血干细胞髓系分化的影响及其相关机制。【方法】体外培养E13胎肝造血细胞，培养造血集落CFU-GM，观察VEGF和PlGF对胎肝造血干细胞髓系分化的作用，应用MTT法来评估不同浓度的PI3-K/Akt抑制剂LY294002对胎肝造血细胞增殖的影响及其对VEGF和PlGF调控胎肝造血作用的影响， Western-Blot检测不同处理条件对胎肝造血细胞Akt蛋白以及p-Akt蛋白表达水平的影响。【结果】VEGF和PlGF均促进胎肝造血干细胞髓系分化，集落数分别为对照组的141%（P<0.05）和123%（P<0.05）；经PlGF处理的胎肝造血细胞后，p-Akt蛋白表达水平是对照组的143%（P<0.01）；VEGF和PlGF分别处理以及联合处理后，与对照组的总Akt蛋白表达水平相比，差异没有统计学意义。不同浓度的LY294002抑制胎肝造血细胞的增殖，并具有明显的剂量依赖性（r=0.9647，P<0.01），LY294002可抑制VEGF和PlGF调控胎肝造血干祖细胞调控髓系分化的作用，集落数为单独存在时的11.5%（P<0.001）和14.5%（P<0.001）。【结论】VEGF和PlGF均能促进胎肝造血干细胞的髓系分化；PlGF可通过上调胎肝造血细胞Akt的磷酸化水平调节胎肝造血细胞的髓系分化。

LY294002 inhibits myeloid differentiation of murine fetal liver hematopoiesis regulated by VEGF and PlGF

【Objective】To investigate the effects of VEGF and PlGF on the myeloid differentiation of murine fetal liver hematopoietic stem cells and related mechanism.【Methods】E13 murine fetal liver hematopoietic cells were isolated and cultured in vitro to evaluate the effects of VEGF and PlGF on the myeloid differentiation of murine fetal liver hematopoietic stem cells. the influence of LY294002 on proliferation of fetal liver hematopoietic cells was detected by MTT assay. The influence on proliferation of hematopoietic progenitor cells were detected by the colony forming unit(CFU) formation assay. Western blotting was used to determine the level of Akt and p-Akt expression in hematopoietic cells treated by different treatment.【Results】The yield of CFU-GM was increased by the application of VEGF and PlGF, in which the VEGF group was 141% compare to control group（P<0.05）, whiles the PlGF group was 123% compare to control group（P<0.05）. With the treatment of PlGF, the p-Akt expression level was increased to 143% compare to control group（P<0.01）. In the VEGF group, the PlGF group and the combination of VEGF and PlGF group, the change of Akt expression level were slightly compare to control group. LY294002 significantly inhibits the proliferation of fetal liver hematopoietic cells, and the impact of inhibitor was dose-dependent（r=0.9647，P<0.01）. When combined with LY294002, the CFU-GM of each group decrease dramatically, in which the combination of VEGF and LY294002 group was 11.5% in VEGF group（P<0.001）,and the combination of PlGF and LY294002 group was 14.5% in PlGF group（P<0.001）.【Conclusion】The myeloid differentiation of the fetal liver hematopoietic cells could be promoted by VEGF and PlGF. PlGF promotes the myeloid differentiation by up-regulating the phosphorylation of Akt.