Inhibition of Tissue Factor-Factor VIIa-catalyzed Factor X Activation by Factor Xa-Tissue Factor Pathway Inhibitor

Salemink, Irene; Franssen, Jo; Willems, George M.; Hemker, H.C.; Lindhout, Théo

doi:10.1074/jbc.274.40.28225

Cited by 20 publications

(17 citation statements)

References 49 publications

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“…Recombinant human tissue factor was a kind gift of Dr Y. Nemerson (Mount Sinai School of Medicine, New York, NY, USA) and was relipidated as described before [13]. Human α‐thrombin was prepared as previously described [14].…”

Section: Methodsmentioning

confidence: 99%

von Willebrand factor stimulates thrombin-induced exposure of procoagulant phospholipids on the surface of fibrin-adherent platelets

Briedé

Wielders

Heemskerk

et al. 2003

Journal of Thrombosis and Haemostasis

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Summary. Studies from our laboratory have demonstrated that von Willebrand factor (VWF) stimulates thrombin generation in platelet-rich plasma. The precise role of VWF and fibrin in this reaction, however, remained to be clarified. In the present study we utilized thrombin-free planar fibrin layers and washed platelets to examine the relationship between platelet-fibrin interaction and exposure of coagulation-stimulating phosphatidylserine (PS) under conditions of low and high shear stress. Our study confirms that platelet adhesion to fibrin at a shear rate of 1000 s À1 requires fibrin-bound VWF. ), but only a minority of the platelets (11 AE 8%) exposed PS. The essential role of VWF in this thrombin-induced procoagulant response became apparent from low shear rate perfusion studies over fibrin that was incubated with VWF and botrocetin. After treatment with thrombin, the majority of the adherent platelets (57 AE 23%) exposed PS and had peak values of [Ca 2þ ] i of about 0.6 mmol L À1 . Taken together, these results demonstrate that thrombin-induced exposure of PS and high calcium response on fibrin-adherent platelets depends on shear-or botrocetin-induced VWF-platelet interaction.Keywords: fibrin, platelet procoagulant activity, von Willebrand factor.Thrombus formation at an injured vessel wall involves platelet adhesion, platelet activation and fibrin formation. Previous studies have provided evidence that fibrin, besides physically entrapping platelets [1], may also be involved in signal pathways that result in the exposure of anionic phospholipids (PS) at the plasma membrane of platelets [2,3]. The presence of PS in the outer leaflet of the platelet plasma membrane is of physiological importance because of its critical role in maintaining thrombin generation at the surface of a developing thrombus [4]. Platelets adhere to fibrin by molecular mechanisms that vary with the surface shear rate [5,6]. At low shear rates, platelet adhesion is mediated by integrin a IIb b 3 whereas at high shear rates an interaction between platelet glycoprotein (GP) Ib and fibrin-bound von Willebrand factor (VWF) tethers the platelets as a prerequisite for an irreversible, integrin a IIb b 3 -mediated, adhesion to fibrin [7][8][9][10].Recently, conflicting reports appeared on the role for GPIb in the development of procoagulant platelets. Studies in plateletrich plasma revealed that VWF supports thrombin generation by two mechanisms: one that involves integrin a IIb b 3 but not fibrin and another one that depends on both fibrin and GPIb [3]. Other investigators studied the thrombin-dependent expression of procoagulant activity in suspensions of gel-filtered platelets and found that the GPIb binding site for thrombin, but not that for VWF, has a key role in the exposure of procoagulant phospholipids on the platelet surface, implying that VWF does not function in this response [11]. Earlier studies, however, indicated that PAR1 is the primary mediator of thrombin-stimulated platelet procoagulant activity, implicating that GPIb doe...

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Section: Methodsmentioning

confidence: 99%

von Willebrand factor stimulates thrombin-induced exposure of procoagulant phospholipids on the surface of fibrin-adherent platelets

Briedé

Wielders

Heemskerk

et al. 2003

Journal of Thrombosis and Haemostasis

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“…Human FXa was obtained from Enzyme Research Laboratories (South Bend, IN). TFPI was kindly provided by T. Lindhout (Cardiovascular Research Institute Maastricht) (40). Full-length TFPI was produced in Escherichia coli, and the truncated variant of TFPI (amino acid residues 1-161) was expressed in Sacharomyces cerevisiae.…”

Section: Methodsmentioning

confidence: 99%

Protein S stimulates inhibition of the tissue factor pathway by tissue factor pathway inhibitor

Hackeng

Seré

Tans

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

295

365

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Tissue factor (TF) plays an important role in hemostasis, inflammation, angiogenesis, and the pathophysiology of atherosclerosis and cancer. In this article we uncover a mechanism in which protein S, which is well known as the cofactor of activated protein C, specifically inhibits TF activity by promoting the interaction between full-length TF pathway inhibitor (TFPI) and factor Xa (FXa). The stimulatory effect of protein S on FXa inhibition by TFPI is caused by a 10-fold reduction of the Ki of the FXa͞TFPI complex, which decreased from 4.4 nM in the absence of protein S to 0.5 nM in the presence of protein S. This decrease in Ki not only results in an acceleration of the feedback inhibition of the TF-mediated coagulation pathway, but it also brings the TFPI concentration necessary for effective FXa inhibition well within range of the concentration of TFPI in plasma. This mechanism changes the concept of regulation of TF-induced thrombin formation in plasma and demonstrates that protein S and TFPI act in concert in the inhibition of TF activity. Our data suggest that protein S deficiency not only increases the risk of thrombosis by impairing the protein C system but also by reducing the ability of TFPI to down-regulate the extrinsic coagulation pathway.anticoagulant ͉ venous thrombosis ͉ extrinsic coagulation

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“…The Rotating Disc Device-Rotating disc experiments were performed in a device described previously (15). Briefly, a circular glass coverslip with a diameter of 20 mm (Menzel Glä ser, Braunschweig, Germany), was rotated at 63 rad/s at the bottom of a cylindrical reaction vessel containing reactants in 3 ml of buffer A.…”

Section: Methodsmentioning

confidence: 99%

Regulation of Platelet Factor Va-dependent Thrombin Generation by Activated Protein C at the Surface of Collagen-adherent Platelets

Briedé

Tans

Willems

et al. 2001

Journal of Biological Chemistry

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Recent studies have indicated that factor Va bound to activated platelets is partially protected from inactivation by activated protein C (APC). To explore whether this sustained factor Va activity could maintain ongoing thrombin generation, the kinetics of platelet factor Vadependent prothrombinase activity and its inhibition by APC were studied. In an attempt to mimic physiologically relevant conditions, platelets were adhered to collagen type I-coated discs. These discs were then spun in solutions containing prothrombin and factor Xa either in the absence or presence of APC. The experiments were performed in the absence of platelet-derived microparticles, with thrombin generation and inhibition confined to the surface of the adherent platelets. APC completely inactivated platelet-associated prothrombinase activity with an overall second order rate constant of 3.3 ؋ 10 6 M ؊1 s ؊1 , which was independent of the prothrombin concentration over a wide range around the apparent K m for prothrombin. Kinetic studies on prothrombinase assembled at a planar phospholipid membrane composed of 25 mol % phosphatidylserine and 75 mol % phosphatidylcholine revealed a similar second order rate constant of inhibition (2.5 ؋ 10 6 M ؊1 s ؊1 ). Collectively, these data demonstrate that ongoing platelet factor Va-dependent thrombin generation at the surface of collagen-adherent platelets is effectively inhibited by APC. No differences were observed between the kinetics of APC inactivation of plasma-derived factor Va or platelet factor Va as part of the prothrombinase associated with, respectively, a planar membrane of synthetic phospholipids or collagen-adherent platelets.

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Inhibition of Tissue Factor-Factor VIIa-catalyzed Factor X Activation by Factor Xa-Tissue Factor Pathway Inhibitor

Cited by 20 publications

References 49 publications

von Willebrand factor stimulates thrombin-induced exposure of procoagulant phospholipids on the surface of fibrin-adherent platelets

von Willebrand factor stimulates thrombin-induced exposure of procoagulant phospholipids on the surface of fibrin-adherent platelets

Protein S stimulates inhibition of the tissue factor pathway by tissue factor pathway inhibitor

Regulation of Platelet Factor Va-dependent Thrombin Generation by Activated Protein C at the Surface of Collagen-adherent Platelets

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