Abstract:

BACKGROUND: Erythropoietin (EPO) can promote the proliferation and migration of endothelial cells to form new vessels, so EPO may play an important role in functional activation of endothelial progenitor cells (EPCs). Except hematopoiesis, whether EPCs are a target of EPO remains poorly understood.
OBJECTIVE: To investigate the effects of EPO on functional activation of EPCs and its signal pathway.
METHODS: EPCs were separated from bone marrow of rats using density gradient centrifugation. First, cells were divided into control group (serum-free DMEM culture medium), recombinant human erythropoietin (rhEPO) in different dose groups (500,    1 000, 2 000 U/L), EPO (2 000 U/L) and the ERK inhibitor FR180204 (50 μmol/L) interaction group. Proliferation, migration, tubes formation and Bcl-2 expression of EPCs were detected with MTT assay, Transwell chamber, Matrigel and Western blot assay respectively. Secondly, cells were divided into control group (serum-free DMEM culture medium), rhEPO group (2 000 U/L), rhEPO (2 000 U/L) and JAK2 inhibitor SD1029 (10 µmol/L) interaction group. P-ERK expression of EPCs was detected by Western blot assay.
RESULTS AND CONCLUSION: Compared with control group, EPO significantly increased EPCs proliferation, the number of migrating cells and tubes formation, up-regulated Bcl-2 protein expression in a dose-dependent manner in a certain rage. After added ERK inhibitor FR180204, these effects were significantly decreased compared with the rhEPO group (2 000 U/L). In addition, compared with the control group, the p-ERK1/2 expression in the rhEPO group (2000 U/L) was significantly up-regulated, JAK2 inhibitor SD1029 made the result reduced markedly. These indicate that EPO can promote functional activity of EPCs, which might be modulated by JAK2-dependent ERK signal pathway.