Overexpression of miR-126 promotes the differentiation of mesenchymal stem cells toward endothelial cells via activation of PI3K/Akt and MAPK/ERK pathways and release of paracrine factors

Abstract

The endothelial cell (EC)-specific miRNA, miR-126, is known to promote angiogenesis in response to angiogenic factors by repressing negative regulators of signal transduction pathways; however, whether miR-126 might regulate the differentiation of stem cells toward endothelial lineage remains unknown. To answer this question, in this study mesenchymal stem cells (MSCs) harvested from C57BL/6 mouse bone marrow were transfected with miR-126 (MSCmiR-126) using recombinant lentiviral vectors. Results showed the para-secretion and the expression levels of phosphorylated PI3K p85, Akt, p38, ERK1 protein in the MSCmiR-126 group were dramatically increased when compared with the control group. With half culture medium refreshed every 3 days, a small number of 6-day-cultured MSCmiR-126 differentiated into endothelial-like cells and most of 9-day-cultured MSCmiR-126 formed a cobblestone-like structure. These differentiated cells evidently expressed EC-specific makers and possessed mature ECs function, while inhibition of paracrine factors suppressed the MSC-EC differentiation. Strikingly, the increased secretion of MSCmiR-126 and their endothelial-differentiated potential were deprived by using a PI3K or MEK chemical inhibitor. Our results suggest that overexpression of miR-126 agumenting the endothelial differentiation of MSCs might in part be attributable to the activation of PI3K/Akt and MAPK/ERK pathways and an increased release of paracrine factors.

MicroRNA-mediated regulation of differentiation and trans-differentiation in stem cells

“…The increased expression of let-7 family members is consistent with observations that let-7 miRNAs are involved in repressing pluripotency factors and increased upon ESC differentiation [53]. Huang et al also reported that MSCs transfected with lentiviral vectors containing miR-126 had increased propensity towards endothelial differentiation indicating the additive effects of pro-endothelial differentiation miRNAs [117]. A recent study revealed that although miR-17-92 is important for regulating vascular integrity and angiogenesis, none of the members had a significant effect on the endothelial differentiation of mouse ESCs and iPSCs [118].…”

Protective Effects of MicroRNA-126 on Human Cardiac Microvascular Endothelial Cells Against Hypoxia/Reoxygenation-Induced Injury and Inflammatory Response by Activating PI3K/Akt/eNOS Signaling Pathway

“…In addition, endothelial cells respond to various proteins and growth factors that regulate angiogenesis [35]. VEGF is important for regulating the function of endothelial cells, in which miR-126 positively regulates the response of ECs to VEGF [36]. A previous study has indicated that miR-126 could regulate tumor angiogenesis, and the decreased expression of miR-126 is correlated with the increased mRNA and protein levels of VEGF-A, which indicated that the up-regulation of miR-126 reduced endothelial cell lumen formation ability and VEGF-induced migration [35].…”

The role of mechanical stimuli in the vascular differentiation of mesenchymal stem cells

“…Guanosine triphosphate (GTP) can provoke further conformational changes of the receptor, leading to its association with Ras, which in turn activates phosphoinositide 3-kinase (PI3K)-Akt pathway. This pathway has been shown to regulate MSC survival, proliferation, migration and other cellular fates through crosstalk with the Wntsignaling pathway (Huang et al, 2013). Furthermore, it has been shown that during endothelial cell differentiation of hASCs in response to shear stress, the acquisition of endothelial cell characteristics also depends on the PI3K-Akt pathway .…”