Abstract
This research explores the role of microRNA in senescence of human endothelial progenitor cells (EPCs) induced by replication. Hsa-miR-134-5p was found up-regulated in senescent EPCs where overexpression improved angiogenic activity. Hsa-miR-134-5p, which targeted transforming growth factor β-activated kinase 1-binding protein 1 (TAB1) gene, down-regulated TAB1 protein, and inhibited phosphorylation of p38 mitogen-activated protein kinase (p38) in hsa-miR-134-5p-overexpressed senescent EPCs. Treatment with siRNA specific to TAB1 (TAB1si) down-regulated TAB1 protein and subsequently inhibited p38 activation in senescent EPCs. Treatment with TAB1si and p38 inhibitor, respectively, showed angiogenic improvement. In parallel, transforming growth factor Beta 1 (TGF-β1) was down-regulated in hsa-miR-134-5p-overexpressed senescent EPCs and addition of TGF-β1 suppressed the angiogenic improvement. Analysis of peripheral blood mononuclear cells (PBMCs) disclosed expression levels of hsa-miR-134-5p altered in adult life, reaching a peak before 65 years, and then falling in advanced age. Calculation of the Framingham risk score showed the score inversely correlates with the hsa-miR-134-5p expression level. In summary, hsa-miR-134-5p is involved in the regulation of senescence-related change of angiogenic activity via TAB1-p38 signalling and via TGF-β1 reduction. Hsa-miR-134-5p has a potential cellular rejuvenation effect in human senescent EPCs. Detection of human PBMC-derived hsa-miR-134-5p predicts cardiovascular risk.