Shear Stress Induces Differentiation of Arterial Endothelial Cells From Murine Embryonic Stem Cells

摘要

The development of vasculature in the embryo has been assumed to depend on the influence of fluid mechanical forces, but the cellular and molecular mechanisms of its development are still poorly understood. The aim of the present study was to investigate whether shear stress affects embryonic stem (ES) cell differentiation. When VEGF receptor 2 (VEGF2)-positive murine ES cells were exposed to shear stress in a flow-loading device, expression of the endothelial cell (EC) markers VEGFR2, Flt-1, VE-cadherin, and PEC AM-1 increased at both the protein level and the mRNA level, but expression of the mural cell marker SM-o-actin, blood cell marker CD3, or the epithelial cell marker keratin remained unchanged. These findings indicate that shear stress selectively promote the differentiation of VEGFR2-positive ES cells into the EC lineage. Shear stress also increased expression of the arterial EC marker ephrinB2, whereas it decreased expression of the venous EC marker EphB4. Shear stress induced tyrosine phosphorylation of VEGFR and caused Notch cleavage in VEGFR2-positive ES cells. The VEGFR kinase inhibitor SU1498 abolished shear stress-induced VEGFR phosphorylation, Notch cleavage, and increase in ephrinB2 expression. The y-secretase inhibitors DAPT and L685.4S8 also blocked shear-stress induced Notch cleavage and up-regulation of ephrinB2 expression. Taken together, these findings suggest that shear stress induces differentiation of ES cells into arterial ECs through the VEGF-Notch signaling pathways.