MicroRNA alterations in senescent endothelial progenitor cells induced by remnant-like lipoproteins.

Background: Remnant-like lipoproteins (RLPs) have been demonstrated to accelerate the onset of endothelial progenitor cells (EPCs) senescence. Recent study has determined that microRNAs (miRNAs) were closely associated with cellular proliferation and senescence. This study aimed to examine whether RLPs lead to an alteration of miRNAs in senescent EPCs.

Methods: RLPs were prepared from plasma samples with immunoaffinity method. After 8 days of culture, EPCs were identified by flow cytometry analysis. Cells were incubated with RLPs for 72 hours. The senescent markers p16INK4a and senescence-associated beta-galactosidase (SA-β-gal) were detected by Western blotting analysis and β-gal staining assay, respectively. A human miRNA microarray containing 723 miRNAs was used to detect the expression profile of miRNAs in control and senescent EPCs. The result from the above microarray was qualified by RT-PCR assay.

Results: RLPs dose-dependently up-regulated the protein level of p16(INK4a) in EPCs, and RLPs at a concentration of 100 µg/ml induced a significant increase in the percentage of SA-β-gal-positive EPCs. Of 723 miRNAs, four miRNAs expressed differentially and significantly in RLPs-treated EPCs (P < 0.05), then their changes in expression were validated by real-time RT-PCR. Among them miR-148b and miR-155 were upregulated while miR-574-3p was down-regulated significantly when compared with control (P < 0.01).

Conclusions: RLPs result in the onset of EPCs senescence. Senescent EPCs induced by RLPs exhibit a different profile of miRNAs. These three miR-148b and miR-155 and miR-574-3p reach a significant difference when compared with control, indicating that microRNA might take part in RLPs-induced EPCs senescence.