G protein-dependent basal and evoked endothelial cell vWF secretion.

TitleG protein-dependent basal and evoked endothelial cell vWF secretion.
Publication TypeJournal Article
Year of Publication2013
AuthorsRusu L, Andreeva A, Visintine DJ, Kim K, Vogel SM, Stojanovic-Terpo A, Chernaya O, Liu G, Bakhshi FR, Haberichter SL, Iwanari H, Kusano-Arai O, Suzuki N, Hamakubo T, Kozasa T, Cho J, Du X, Minshall RD
Date Published2013 Sep 30

von Willebrand factor (vWF) secretion by endothelial cells (EC) is essential for hemostasis and thrombosis, however, the molecular mechanisms are poorly understood. Interestingly, we observed increased bleeding in EC-Gα13(-/-);Gα12(-/-) mice that could be normalized by infusion of human vWF. Blood from Gα12(-/-) mice exhibited significantly reduced vWF levels but normal vWF multimers and impaired laser-induced thrombus formation indicating Gα12 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 Gα12(-/-) whereas thrombin-induced vWF secretion was defective in both EC-Gαq(-/-);Gα11(-/-) and Gα12(-/-) mice. Using siRNA in cultured HUVEC and HPAEC, depletion of Gα12 and α-SNAP (but not Gα13) inhibited both basal and thrombin-induced vWF secretion while over-expression of activated Gα12 promoted vWF secretion. In Gαq, p115 RhoGEF, and RhoA-depleted HUVEC, thrombin-induced vWF secretion was reduced by 40% whereas basal secretion was unchanged. Finally, in vitro binding assays revealed Gα12 N-terminal residues 10-15 mediated the binding of Gα12 to α-SNAP, and an engineered α-SNAP binding-domain minigene peptide blocked basal and evoked vWF secretion. Discovery of obligatory and complementary roles of Gα12 and Gαq/11 in basal vs. evoked EC vWF secretion may provide promising new therapeutic strategies for treatment of thrombotic disease.

Alternate JournalBlood