Erythropoietin promotes endothelial progenitor cells proliferation depending on PI3k/Akt pathway / 中国组织工程研究

ABSTRACT

BACKGROUND:It has been proved that erythropoietin can promotes angiogenesis in injured tissue, which is closely related to the proliferation and differentiation of endothelial progenitor cel s. However, the involved mechanism remains unclear yet. OBJECTIVE:To investigate the effect of erythropoietin on the function and activity of bone marrow-derived endothelial progenitor cel s in mice, and to explore the signal pathway. METHODS:The endothelial progenitor cel s from the bone marrow of mice were separated by means of density gradient centrifugation and then cultured. The cel s were preconditioned by specific inhibitor of PI3K (LY294002), and were divided into the fol owing groupsEGM-2 group, three erythropoietin preconditioned groups (the concentrations of erythropoietin in medium were 1, 5, 10 U/mL respectively), erythropoietin+LY group (10 U/mL erythropoietin and 10 mmol/L LY294002 in medium), LY group (10 mmol/L LY294002 in medium), dimethyl sulfoxide group (1 mL/L dimethyl sulfoxide in medium). The cel proliferation and apoptosis were evaluated by cel counting kit-8 and flow cytometry respectively. The contents of endothelial nitric oxide synthase and vascular endothelial growth factor in cel lysates were detected by the method of ELISA, and the expressions of Akt and p-Akt were by western blot assay. RESULTS AND CONCLUSION:Erythropoietin could promote the proliferation of endothelial progenitor cel s in a dose-dependent manner, which was, however, completely inhibited by LY294002. The apoptosis rate in the erythropoietin preconditioned groups was significantly lower than that in the erythropoietin+LY group. The contents of endothelial nitric oxide synthase and vascular endothelial growth factor in cel lysates of LY group and erythropoietin+LY group were significantly lower than those in the erythropoietin groups. There was no difference in Akt expression found in each group, while the p-Akt expression in the erythropoietin+LY group was significantly lower than that in the erythropoietin groups. The above results reveal that erythropoietin can promote the proliferation of endothelial progenitor cel s and decrease the cel apoptosis, which is depending on PI3K/Akt signal pathway.