Factor VIIa stimulates endothelin-1 synthesis in TNF-primed endothelial cells by activation of protease-activated receptor 2

Abstract

The mechanisms linking prothrombotic changes to endothelial dysfunction and accelerated atheroma formation have yet to be fully defined. Expression of TF (tissue factor) on the endothelium is potentially an initiating event as binding and activation of FVII (factor VII) can result in thrombosis. Although PAR2 (protease-activated receptor-2) is expressed on vascular endothelium, its precise physiological significance and mechanism of activation have yet to be defined. In the present study, we investigated whether PAR2 can be activated by FVIIa (activated FVII) and induce ET-1 (endothelin-1) synthesis. In bovine aortic endothelial cells pretreated with TNF (tumour necrosis factor-alpha) to increase TF expression, FVIIa stimulated ET-1 synthesis via activation of PAR2. Although FX (factor X) alone was inactive, this response was enhanced by using FVII and FX in combination. Inhibition of the proteolytic activity of FVIIa abolished the response. The PAR2 agonist peptide SLIGKV also enhanced ET-1 release on TNF-pretreated cells. The response to FVIIa was inhibited by a PAR2 antagonist peptide FSLLRY. Inhibition of the p38 MAPK (mitogen-activated protein kinase) reduced PAR2 expression and the ET-1 response. In summary, FVIIa can stimulate ET-1 synthesis in endothelial cells by activating PAR2, demonstrating a potential link between thrombotic processes and endothelial cell dysfunction.

Protease-activated receptor-2 activation: a major actor in intestinal inflammation

“…Previous studies have indicated that PAR 2 is also highly expressed on the endothelium where the activators of PAR 2 can stimulate the synthesis of endothelin and exocytosis of adhesion molecules 21 22. Previous studies have shown that PAR 2 agonists can induce leukocyte rolling/adherence along the mesenteric venules, whereas leukocyte rolling was reduced in the cremaster muscles of PAR 2 -deficient mice submitted to surgical trauma 13 23.…”

Luminal Cathepsin G and Protease-Activated Receptor 4

“…After 60 minutes, fluorescence intensity was measured. To assess the respective role of PAR 1 , PAR 2 , and PAR 4 in the influence of UC fecal supernatants on CPP: (i) P4-pal10 pepducin (final concentration 1 mol/L) (NeoMPS, Strasbourg, France), (ii) PAR 1 antagonist FLLRN (PheLeu-Leu-Arg-Asn, 10 mol/L, Peptides International, Louisville, KY), 13,14 (iii) PAR 2 antagonist FSLLRY (PheSer-Leu-Arg-Tyr, 10 mol/L, Bachem, Weil am Rhein, Germany), 15 or (iv) physiological saline, as a control, were added to the mucosal side of each chamber before administration at the mucosal side of either fecal supernatants or physiological saline. In another series of experiments, PAR 4 agonist peptide (Ala-Tyr-Pro-Gly-LysPhe-NH 2, 50 mol/L, Sigma) was added into the mucosal compartment, and CPP was measured after 1 hour.…”

Characterisation of preproendothelin-1 derived peptides identifies Endothelin-Like Domain Peptide as a modulator of Endothelin-1

“…Stimulation with TNFα (10 ng/ml) increases EDN1 mRNA levels 33 . Consistent with this, levels of NT-proET-1 and CT-proET-1 in conditioned media samples significantly increased.…”