Effect of angiotensin II on the proliferation of bone marrow-derived endothelial progenitor cells and possible mechanism

Objective To study the effect of angiotensin Ⅱ(AngⅡ)on the proliferation of bone marrow-derived endothelial progenitor cells(EPCs)and its possible mechanism.Methods Mononuclear cells(MNCs) were isolated from bone marrow of rats by density gradient centrifugation.Then the MNCs were induced to differentiate into EPCs after 7 days of culture.EPCs were characterized as adherent cells double labeled with AC133 and Flk-1 by fluorescent staining and identified under laser scanning confocal microscope.Attached cells were collected and divided into different groups.A series of concentrations of AngⅡ(107 mol/L,10-8 mol/L,10-9 mol/L)were added to each group for intervention.The change in EPCs proliferative activity after the intervention was evaluated by MTT assay.RT-PCR was used to determine the change of Flk-1 mRNA expression in EPCs after the intervention by AngⅡ at different concentrations or pretreatment with valsartan or GFX,an inhibitor of protein kinase C,before AngⅡ stimulation.Results AngⅡ enhanced the proliferative ability of EPCs in the presence of VEGF,and increased Flk-1 mRNA expression.The effects of AngⅡ was blocked by valsartan or GFX.Conclusion It is suggested that AngⅡ may up-regulate Flk-1 mRNA expression of EPCs through AngⅡ type 1 receptor and PKC pathway,which results in the proliferation of EPCs and then benefits vasculogenesis.