TGF-β receptor kinase inhibitor enhances growth and integrity of embryonic stem cell–derived endothelial cells

Abstract

Recent findings have shown that embryonic vascular progenitor cells are capable of differentiating into mural and endothelial cells. However, the molecular mechanisms that regulate their differentiation, proliferation, and endothelial sheet formation remain to be elucidated. Here, we show that members of the transforming growth factor (TGF)-β superfamily play important roles during differentiation of vascular progenitor cells derived from mouse embryonic stem cells (ESCs) and from 8.5–days postcoitum embryos. TGF-β and activin inhibited proliferation and sheet formation of endothelial cells. Interestingly, SB-431542, a synthetic molecule that inhibits the kinases of receptors for TGF-β and activin, facilitated proliferation and sheet formation of ESC-derived endothelial cells. Moreover, SB-431542 up-regulated the expression of claudin-5, an endothelial specific component of tight junctions. These results suggest that endogenous TGF-β/activin signals play important roles in regulating vascular growth and permeability.

Glioblastoma-secreted factors induce IGFBP7 and angiogenesis by modulating Smad-2-dependent TGF-β signaling

“…Both TGF-b1-and U87MG-CM-induced Smad-2 and Smad-1/-5 phosphorylation were inhibited in the presence of SB431542. As SB431542 has no effect on ALK1/Smad phosphorylation (Goumans et al, 2003;Watabe et al, 2003), these observations suggest that ALK1-mediated phosphorylation of Smad-1/-5 in HBEC cells is probably induced secondary to the activation of ALK5. Findings by Goumans et al (2003) demonstrating that ALK5 kinase activity is required for ALK1 activation by TGF-b support this conclusion.…”

Transforming Growth Factor-β Regulates the Growth of Valve Interstitial Cells in Vitro

“…By acting as an ATP mimetic, it disrupts the receptor kinase activity and abolishes TGF-␤-mediated cellular responses in many cell types. 28,55 Intriguingly, although this inhibitor is able to abolish the growth-suppressive effect of exogenous TGF-␤, on its own, it decreases cell number without affecting cell survival. One likely explanation, as noted later, is that the various non-Smad pathways activated by TGF-␤ may function independently to oppose the Smadmediated effects; in addition, the net cellular response depends on the extent of activation or suppression of each individual pathway.…”

“…SB431542 is a potent inhibitor of TGF-␤RI. [27][28][29] Solid anhydrous SB431542 (Sigma, St Louis, MO) was dissolved in sterile dimethyl sulfoxide (DMSO) and prepared into a 10 mmol/L stock solution. A specific amount of the stock solution was added to the culture media to achieve desired further dilutions.…”

TGF-β signaling in vascular biology and dysfunction

“…ALK5 induces the expression of fibronectin and plasminogen activator inhibitor type 1 (PAI-1), a negative regulator of EC migration [34]. Interestingly, in mouse embryonic stem cell-derived ECs, the ALK5 kinase inhibitor SB-431542 enhances EC growth and integrity via up-regulation of the tight junction component Claudin-5, suggesting a role for ALK5 signaling in regulating vascular permeability [35]. ALK5 indeed has been reported to increase TGF-β-induced EC permeability and actin cytoskeleton remodeling [36].…”