Conclusions
The CXCL12/CXCR4/PI3K/pAkt signalling pathway increased progesterone-induced EPC viability.
Methods
EPCs were isolated from bone marrow-derived mononuclear cells (BM-MNCs) and treated with progesterone (5, 10 and 100 nm). MTS assay was used to investigate EPC viability. Protein expression was examined by Western blotting, ELISA assay and flow cytometry. Cell membrane and cytoplasm proteins were extracted with membrane and cytoplasm protein extraction kits. CXCR4 antagonist (AMD3100) and phosphatidylinositol 3-kinases (PI3K) antagonist (LY294002) were used to characterize underlying mechanisms.
Results
Progesterone-induced EPC viability was time- and dose-dependent. Administration of progesterone facilitated EPC viability and increased expression of CXCL12 and phosphorylated Akt (also known as protein kinase B, pAkt) activity (P < 0.05). Progesterone did not regulate CXCR4 protein expression in cultured EPC membranes or cytoplasm. However, progesterone-induced EPC viability was significantly attenuated by AMD3100 or LY294002. Inhibition of the signalling pathway with AMD3100 and LY294002 subsequently reduced progesterone-induced CXCL12/CXCR4/PI3K/pAkt signalling activity. Conclusions: The CXCL12/CXCR4/PI3K/pAkt signalling pathway increased progesterone-induced EPC viability.