The Effect Of MicroRNA-27b On Mice Endothelial Progenitor Cell Senescence Induced By Remnant-like Particles

Background Endothelial progenitor cells (EPCs) are bone marrow-derived cells that home to sites of new blood vessel formation and play an important role in the maintenance of vascular integrity and normal endothelial function. EPCs senescence plays an essential role in the development of atherosclerosis. p16INK4α is a key regulator of progenitor/stem cell senescense. Remnant-like particles (RLPs) from patients with postprandial hypertriglyceridemia are atherogenic and closely related to endothelial dysfunction. RLPs could accelerate the senescense process of EPCs deriving from human peripheral blood mononuclear cells, and dose-dependently up-regulated the protein expression of p161NK4α. MicroRNAs (miRNA/miR) are a class of small (18～22nucleotides) non-coding single strand RNAs that negatively regulate target genes at a post-transcriptional level. Previous studies found that miR-27b decreased in mice senescent EPCs induced by RLPs. It can be conjectured that miR-27b may play a potential role in EPC senescence induced by RLPs.Objective To explore the effect of miR-27b overexpression on EPCs senescence induced by RLPs. Methods EPCs were isolated from mice bone marrow by density gradient centrifugation and then maintained in endothelial basal medium-2containing vascular endothelial growth factor. After seven days of primary culture, EPCs were divided into two groups, miR-27b overexpression group and control group which were transfected by miR-27b mimic or its scramble control, respectively. Twenty four hours later, both groups were stimulated by0.2mg/mL RLPs for further24h. Senescent cells were identified by senescense associated-p-galactosidase (SA-β-Gal) staining. Real-time PCR was applied to assay the mRNA level of miR-27b and p16INK4α.Results Mouse bone marrow-derived EPCs were successfully isolated and cultured in vitro. MiR-27b level was significantly increased～37folds in EPCs. The average percentage of SA-β-Gal positive cells in miR-27b overexpression group was29.4%, while that in control group was21.4%. There was no significant difference in mRNA levels of p16INK4α between these two groups.Conclusion MiR-27b might represse RLP-induced senescence in mice EPCs. However, the exact mechanism needs to be further explored.