| First Author | Rusu L | Year | 2014 |
| Journal | Blood | Volume | 123 |
| Issue | 3 | Pages | 442-50 |
| PubMed ID | 24081657 | Mgi Jnum | J:206486 |
| Mgi Id | MGI:5550338 | Doi | 10.1182/blood-2013-03-489351 |
| Citation | Rusu L, et al. (2014) G protein-dependent basal and evoked endothelial cell vWF secretion. Blood 123(3):442-50 |
| abstractText | von Willebrand factor (vWF) secretion by endothelial cells (ECs) is essential for hemostasis and thrombosis; however, the molecular mechanisms are poorly understood. Interestingly, we observed increased bleeding in EC-Galpha13(-/-);Galpha12(-/-) mice that could be normalized by infusion of human vWF. Blood from Galpha12(-/-) mice exhibited significantly reduced vWF levels but normal vWF multimers and impaired laser-induced thrombus formation, indicating that Galpha12 plays a prominent role in EC vWF secretion required for hemostasis and thrombosis. In isolated buffer-perfused mouse lungs, basal vWF levels were significantly reduced in Galpha12(-/-), whereas thrombin-induced vWF secretion was defective in both EC-Galphaq(-/-);Galpha11(-/-) and Galpha12(-/-) mice. Using siRNA in cultured human umbilical vein ECs and human pulmonary artery ECs, depletion of Galpha12 and soluble N-ethylmaleimide-sensitive-fusion factor attachment protein alpha (alpha-SNAP), but not Galpha13, inhibited both basal and thrombin-induced vWF secretion, whereas overexpression of activated Galpha12 promoted vWF secretion. In Galphaq, p115 RhoGEF, and RhoA-depleted human umbilical vein ECs, thrombin-induced vWF secretion was reduced by 40%, whereas basal secretion was unchanged. Finally, in vitro binding assays revealed that Galpha12 N-terminal residues 10-15 mediated the binding of Galpha12 to alpha-SNAP, and an engineered alpha-SNAP binding-domain minigene peptide blocked basal and evoked vWF secretion. Discovery of obligatory and complementary roles of Galpha12 and Galphaq/11 in basal vs evoked EC vWF secretion may provide promising new therapeutic strategies for treatment of thrombotic disease. |
