Abstract 174: MicroRNA-216a Induces a Premature Senescent-Like Phenotype and Regulates Angiogenic Activity in Human Vascular Endothelial Cells

Abstract

Background: Among the age-associated functional and structural changes, of particular note is cellular senescence of endothelial cells, which plays a key role in endothelial dysfunction and atherogenesis. But the molecular basis of which is not fully defined. We have identified that a particular microRNA, miR-216a , was up-regulated in senescent endothelial cells, here, the present study aimed to determine the role of miR-216a in regulating premature senescence and angiogenic activity of endothelial cells. Methods and results: Human umbilical vein endothelial cells (HUVECs) were cultured and population-doubling levels (PDLs) were calculated during passages. Briefly, PDLs was computed as Log2 (Ch/Cs), where Ch was the number of viable cells at harvest and Cs was the number of cells seeded. PDL8 and PDL44 were respectively identified as young and senescent HUVECs, with increased expression of p53 and p21 and shortened telomere length in PDL44. We found that miR-216a expression is up-regulated by 64% in PDL44 ( P <0.05). Next, we examined the effect of miR-216a on senescence-associated β-galactosidase (SA-β-gal) activity, a characteristic of senescence-related growth arrest. In PDL8 with stable miR-216a lentiviral transfection, we found that miR216a overexpression increased the percentage of SA-β-gal[[Unable to Display Character: –]]positive cells by 1.8-fold compared with control at about 15 days. We also found that telomerase activity was dependent on modulation of miR-216a levels, which confirms a crucial role for miR-216a in HUVEC senescence. To further analyze the effect of miR-216a on endothelial functions, we tested the cell proliferation, migration, adhesion, and tube-formation abilities. The results showed that miR-216a overexpression accelerated the decline of endothelial functions at about 15 days, which led to a significant inhibition of endothelial proliferation and migration by 15% ( P <0.001) and 8% ( P =0.001) and increased adhesion capability of THP-1 cells to HUVECs by 1.9-folds ( P =0.001). There was no significant impairment of tube formation in the Matrigel assay. Conclusions: Our data indicated that miR-216a can promote the premature endothelial senescence and may serve as a target in regulating endothelial dysfunction associated with atherosclerosis.