Screening MiRNA Potentially Modulating Remnant-like-particle-induced Senescence Of Mouse Bone Marrow-derived Endothelial Progenitor Cells

BackgroundEndothelial progenitor cells (EPCs) are precursors of mature vascular endothelial cells, and involve in vascular regeneration and repairing process after endothelial injury. EPCs senescence and dysfunction can induce vascular endothelial dysfunction which is closely associated to the development of atherosclerosis. The postprandial phase is considered to be a critically atherogenic period. In patients with postprandial hypertriglyceridemia, the increased plasma remnant-like particles (RLPs)-cholesterol levels are closely related to vascular endothelial dysfunction. RLPs can accelerate the senescence process of human EPCs derived from peripheral blood mononuclear cells, however, the mechanism is still not clarified. MicroRNAs (miRNAs) are a class of endogenous small non-coding single-stranded RNAs that are highly reserved during evolution, and play important roles in regulating the expressions of eukaryotic genes. Recently, miRNA has been found involving in the regulation of cell senescence. It can be conjectured that miRNA may regulate RLP-induced EPCs senescence.ObjectiveTo explore the effects of RLPs on the senescence process of mouse bone marrow-derived EPCs, and to screen potential miRNAs that may regulate RLPs-induced EPCs senescence. MethodsMononuclear cells were isolated from mouse bone marrow by density gradient centrifugation and differential adhesion method. The remaining cells were cultured and differentiated to EPCs in EBM-2. The expressions of specific antigens(CD34, CD133, Flk-1 and CD31) on cell surface were analyzed by flow cytometer. Taking EPCs stimulated by PBS as control, EPCs were stimulated by 0.1mg/mL RLPs. After stimulation for 12h,24h,48h and 72h, senescent cells in each group were identified by senescence associatedβ-galactosidase (SA-β-gal) staining and characteristic morphology change. MiRNAs in senescent EPCs were screened by miRNA microarray technology.ResultsCells obtained from mouse bone marrow by density gradient centrifugation and differential adhesion method formed clusters at 4d. At 12d, positive ratios of CD34+,CD133+,Flk-1+and CD31+were (65±4)%, (48±3)%, (37±3)%and (51±4)%, respectively. RLPs significantly increased the number of senescent EPCs. The number of senescent EPCs significantly increased at 24h after stimulation by RLPs. The most obvious difference in senescent cell percentage between two groups was observed after 48h. Five miRNAs with twifold changed expressions in senescent EPCs were found by miRNA microarray technology. One significantly upregulated miRNA was miR-542-3p, and four significantly downregulated miRNAs were miR-328, miR-324-5p, miR-27b and miR-191.ConclusionsThere are 5 miRNAs with twifold changed expressions in senescent mouse bone marrow-derived EPCs induced by RLPs, and they may be involved in regulation of RLP-induced EPCs senescence.