G protein-dependent basal and evoked endothelial cell vWF secretion.
Blood
; 123(3): 442-50, 2014 Jan 16.
Article
in En
| MEDLINE
| ID: mdl-24081657
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 N-ethylmaleimide-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.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Von Willebrand Factor
/
RhoA GTP-Binding Protein
/
Endothelial Cells
/
GTP-Binding Protein alpha Subunits, G12-G13
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GTP-Binding Protein alpha Subunits, Gq-G11
Limits:
Animals
/
Humans
Language:
En
Journal:
Blood
Year:
2014
Document type:
Article