Studies Of MiRNA-21 Modulates The Senescence Of Endothelial Progenitor Cells

Aims: To investigate the role of micro-RNA 21 acting upon rat endothelial progenitor cells(EPCs) in the course of senescence; To investigate whether mi R-21 activates the senescence of EPCs via suppressing Hmga2.Methods: 1. By means of Ficoll density gradient centrifugation, bone marrow-derived mononuclear cells(BMMNCs) were isolated from SD rats; Then they were cultured within special EGM-2MV medium during a period of 14 to 28 days; The characters of cultured cells were observed under the optical microscope, the growth curves of which were plotted via CCK8; Flow cytometry technique and experiments of acetylated low-density lipoprotein endocytosis and ulex europaeus I lectin binding was manipulated to attain the identification. Tube formation of EPCs in matrigel in vitro was then addressed; 2. EPCs in generation 10(P10) were transfected with mi R-21 mimics or inhibitors. CCK8 analysis was performed to evaluate the growth of EPCs subjecting to mi R-21; Cell migration analysis was monitored by transwell assay. In vitro, matrigel tube formation assay was implemented to clarify the righteous role of mi R-21 involving the angiogenic activity; Senescence β-galactosidase staining was conducted to demonstrate the function of mi R-21 on the senescence of EPCs; 3. After transfection, total RNAs and proteins were extracted for PCR and Western Blot accordingly; Both m RNA and proteins of the gene were testified using Hmga2.Results: 1.With the method of density gradient centrifugation, cultured cells were found to show EC specific surface markers such as CD 133 and CD 34, VEGFR-2 and had the ability to endocytose ac-LDL and bind UEA I lectin, displaying a high capacity of migration and vessel formation; 2. The down-regulation of mi R-21 promoted EPCs migration through transwell assay and enhanced tube formation by matrigel assay; Down-regulation of mi R-21 impaired the senescence of EPCs; 3.The levels of proteins were lower in which mi R-21 was up-regulated.Conclusion: The senescence of EPCs was inhibited due to mi R-21 down-regulation. The down-regulation of mi R-21 promoted the ability of migration and tube formation in EPCs. Hmga2 was predicted to be the target gene of mi R-21.