Estrogen induces endothelial progenitor cells proliferation and migration by estrogen receptors and PI3K-dependent pathways

Estrogen induces endothelial progenitor cells (EPCs) migration and proliferation, which may serve as a potential target for coronary artery disease, but the mechanisms are unclear. We hypothesized that estrogen receptors (ERs) and phosphatidylinositol 3-kinase (PI3K) signaling pathway, which represent particularly important roles of action for estrogen, may contribute to estrogen-induced EPCs migration and proliferation. Bone marrow mononuclear cells (MNCs) were cultured in Dulbecco’s modified Eagle’s medium (DMEM) supplemented with growth factors as previously described. A total of 87.32 ± 5.13% of adherent cells showed uptake of acetylated low-density lipoprotein and lectin binding. Immunostaining and fluorescence activated cell sorting confirmed the endothelial progenitor phenotype. RT-PCR, immunocytochemistry staining and Western blot demonstrated expression of ERs. Exposure to 17β-estradiol significantly improved EPCs migration and proliferation. Those effects were blocked by pretreatment with the pharmacological PI3K blockers LY294002 (1 h, 10 umol/L) and ICI-182780 (1 h, 10 umol/L), a specific estrogen receptor antagonist, which show involvement of estrogen receptors and PI3K pathway. These results suggest that estrogen induces EPCs migration and proliferation via ERs and PI3K pathway which provided a novel insight and treatment strategy of vascular biology.