G protein-dependent basal and evoked endothelial cell vWF secretion

Luiza Rusu, Alexandra Andreeva, David J. Visintine, Kyungho Kim, Stephen M. Vogel, Aleksandra Stojanovic-Terpo, Olga Chernaya, Guoquan Liu, Farnaz R. Bakhshi, Sandra L. Haberichter, Hiroko Iwanari, Osamu Kusano-Arai, Nobuchika Suzuki, Takao Hamakubo, Tohru Kozasa, Jaehyung Cho, Xiaoping Du, Richard D. Minshall

Research output: Contribution to journalArticlepeer-review

21 Scopus citations

Abstract

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-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 that 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 human umbilical vein ECs and human pulmonary artery ECs, depletion of Gα12 and soluble Nethylmaleimide- sensitive-fusion factor attachment protein α (α-SNAP), but not Gα13, inhibited both basal and thrombin-induced vWF secretion, whereas overexpression of activated Gα12 promoted vWF secretion. In Gαq, 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 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.

Original languageEnglish
Pages (from-to)442-450
Number of pages9
JournalBlood
Volume123
Issue number3
DOIs
StatePublished - Jan 16 2014

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