Clin Res Cardiol 101, Suppl 1, April 2012

P375 - Sphingosine-1-phosphate induces in vitro angiogenesis via the sphingosine-1-phosphate receptor 3 and activation of RhoA
S. Del Galdo1, C. Vettel1, D. Baltus2, S. Lutz3, T. Wieland1
1Institut für Experimentelle u. Klinische Pharmakologie und Toxikologie, Universität Heidelberg, Mannheim; 2Universität Heidelberg, Medizinische Fakultät Mannheim, Mannheim; 3Abteilung Pharmakologie, Universitätsmedizin Göttingen, Göttingen;
Sphingosine-1-phosphate (S1P) elicits numerous biological responses including cell survival, growth, migration, proliferation and tube formation of endothelial cells (EC). These responses are mediated by a family of G-protein-coupled receptors previously named endothelial differentiation genes. Three types of these receptors (S1P1R, S1P2R, S1P3R) have been described in vascular EC. Whereas the Gi-coupled S1P1R is involved in maintaining the endothelial barrier function, the subtype(s) regulating angiogenesis are ill defined. We therefore studied the S1P-induced in vitro spheroid sprouting of human umbilical vein EC (HUVEC) and analyzed the concomitant activation of the RhoGTPases RhoA and Rac1 by effector pull down assays. Physiological relevant concentrations of S1P (100 nM) induce a moderate activation of both, Rac1 and RhoA. The activation of Rac1 was sensitive to NSC23766 (NSC), an inhibitor of Rac1 specific guanine nucleotide exchange factor Tiam1 and was similarly induced by the S1P1R-specific agonist SEW2871, arguing for a Rac1 activation via the S1P1R/Gi/Tiam1 pathway. Therefore we studied the influence of SEW2871, pertussis toxin (PTX) and NSC on in vitro angiogenesis. SEW2871 concentration dependently inhibited angiogenesis whereas PTX and NSC had no influence on S1P-induced sprouting. Inhibition of the S1P2R by its specific antagonist JTE 013 increased basal but had no effect on the S1P-stimulated sprouting. In contrast, the S1P1R and S1P3R antagonist VPC23019 suppressed basal and S1P-induced sprouting angiogenesis in a concentration dependent manner. Suppression of the activity of the Gq/11 protein did not inhibit whereas attenuation of G12/13 signaling blunted S1P-induced RhoA activation. We therefore conclude that angiogenic sprouting of EC is mainly stimulated via the S1P3R subtype and likely involves the activation of RhoA via a G12/13  dependent pathways at physiological relevant S1P concentrations.
Clin Res Cardiol 101, Suppl 1, April 2012
Zitierung mit Vortrags- oder Posternummer s.o.
DOI 10.1007/s00392-012-1100-6