Tissue factor (TF) pathway inhibitor (TFPI) regulates factor X activation through the sequential inhibition of factor Xa and the VIIa.TF complex. Factor Xa formation was studied in a purified, reconstituted system, at plasma concentrations of factor X and TFPI, saturating concentrations of factor VIIa, and increasing concentrations of TF reconstituted into phosphatidylcholine:phosphatidylserine membranes (TF/PCPS) or PC membranes (TF/PC). The initial rate of factor Xa formation was equivalent in ...[more]
Project description:This model is from the article:
A model for the stoichiometric regulation of blood coagulation.
Hockin MF, Jones KC, Everse SJ, Mann KG.
Journal of Biological ChemistryVolume 277, Issue 21, 24 May 2002, Pages 18322 -18333
We have developed a model of the extrinsic blood coagulation system that includes the stoichiometric anticoagulants. The model accounts for the formation, expression, and propagation of the vitamin K-dependent procoagulant complexes and extends our previous model by including: (a) the tissue factor pathway inhibitor (TFPI)-mediated inactivation of tissue factor (TF).VIIa and its product complexes; (b) the antithrombin-III (AT-III)-mediated inactivation of IIa, mIIa, factor VIIa, factor IXa, and factor Xa; (c) the initial activation of factor V and factor VIII by thrombin generated by factor Xa-membrane; (d) factor VIIIa dissociation/activity loss; (e) the binding competition and kinetic activation steps that exist between TF and factors VII and VIIa; and (f) the activation of factor VII by IIa, factor Xa, and factor IXa. These additions to our earlier model generate a model consisting of 34 differential equations with 42 rate constants that together describe the 27 independent equilibrium expressions, which describe the fates of 34 species. Simulations are initiated by "exposing" picomolar concentrations of TF to an electronic milieu consisting of factors II, IX, X, VII, VIIa, V, and VIIII, and the anticoagulants TFPI and AT-III at concentrations found in normal plasma or associated with coagulation pathology. The reaction followed in terms of thrombin generation, proceeds through phases that can be operationally defined as initiation, propagation, and termination. The generation of thrombin displays a nonlinear dependence upon TF, AT-III, and TFPI and the combination of these latter inhibitors displays kinetic thresholds. At subthreshold TF, thrombin production/expression is suppressed by the combination of TFPI and AT-III; for concentrations above the TF threshold, the bolus of thrombin produced is quantitatively equivalent. A comparison of the model with empirical laboratory data illustrates that most experimentally observable parameters are captured, and the pathology that results in enhanced or deficient thrombin generation is accurately described.
Project description:Blood coagulation model investigating effects of Xa-inhibitors (Rivaroxaban and Apixaban). Model is an extension of Pohl1994 and reduced from Wajima2009.
Encoding the model from the supplementary files results in 43 species, 82 reactions and 111 parameters. Including the drug (Xa-inhibitor) and drug-Xa complexes results in 46 species, 84 reactions and 115 parameters (+1 dummy variable to change inhibitory kinetic parameters depending on which drug is simulated). The publication lists there being 45 species, 84 reactions and 116 parameters. Publication figure 2 has 45 species present however the complex VIIa:Xa (reaction 51 involving Xa and VIIa) is not shown. This figure also has numerous small errors such as listing IXa:ATIII complex twice (instead of one being XIa:ATIII), not showing XIa:ATIII, typo ('Va' -> Va), typo (IXa + VIIIa -> IXA:'VIIa').
Rate laws for Xa-drug interactions were assumed to be mass action.
Project description:Reused mathematical model (Hockin et al., 2002) of blood coagulation simulating the effects of coagulation factor inhibitors, fondaparinux (synthetic heparin) and Rivaroxaban. Fondaparinux (Fpx) simulated to reversibly bind with ATIII before irreversibly binding to Xa, IXa, mIIa, TF:VIIa, Xa:Va and IIa. Rivaroxaban simulated to bind reversibly to Xa and Xa:Va.
Project description:Mathematical model of blood coagulation. Reused Wajima2009 model with modifications to reactions 27 (formation of Va:Xa complex), 32 (Xa inhibition by TFPI) and 45 (Xa inhibition by TFPI-Heparin complex) as described in publication equations 2,3 and 4. Publication lists parameter sets to simulate Rivaroxaban, VKA and Enoxaparin (supplementary files).
Project description:Cancer patients often have an activated clotting system and are at increased risk for venous thrombosis. In this study, we analyzed tissue factor (TF) expression in four different human pancreatic tumor cell lines for the purpose of producing derivative tumors in vivo. We found that two of the lines expressed TF and released TF-positive microparticles (MPs) into the culture medium. The majority of TF protein in the culture medium was associated with MPs. Importantly, only TF-positive cell lines activated coagulation in nude mice, and this activation was abolished by an anti-human TF antibody. Of the two TF-positive lines only one produced detectable levels of human MP TF activity in the plasma when grown orthotopically in nude mice. Surprisingly, <5% of human TF protein in plasma from tumor-bearing mice was associated with MPs. Mice with TF-positive tumors and elevated levels of circulating TF-positive MPs had increased thrombosis in a saphenous vein model. In contrast, we observed no difference in thrombus weight between tumor bearing and control mice in an inferior vena cava stenosis model. Our studies suggest that in a xenograft mouse model tumor TF activates coagulation, whereas TF on circulating MPs may trigger venous thrombosis. Overall design: 8 human tumor pancreatic cell lines
Project description:System of ODEs to describe the behaviour of the activated factors of the extrinsic pathway of blood coagulation with the addition of the TFPI-Xa complex. Mass-action kinetics used with the only exception of factor IIa production (Michaelis-Menten rate law).
Project description:Mathematical model of blood coagulation investigating effects of varied factor VIIa on thrombin generation. Model derived from Hockin2002/Butenas2004. Butenas added two new reactions (R28 and R29) and two new parameters (k43 and k44). Here, changes to parameters k32 and k38 and TF initial conc. changed to 5e-12
Project description:Mathematical model of blood coagulation. Extended model of Mitrophanov2011 (which is an extension of Hockin2002). Additional reactions added involving thrombin. Modelling the effects of dilution and addition of recombinant factor VIIa, II, VII, IX, X, AT.
Project description:Analysis of coagulation factor FVII-induced breast cancer cell transformation at gene expression level. The hypothesis tested in the present study was that expression of FVII upregulates genes involved in epithelial-to-mesenchymal transition and transformation. Results provide important information on the cellular response to tumor FVII expression with respect to pro-oncogenic programs . Overall design: Total RNA obtained from an MDA-MB-231-based cell line (MDA-FRT; an MDA-MB-231 cell line containing a flp-in FRT site) containing human FVII cDNA (2A3-3-flTF) compared to cells expressing an empty vector control (pcDNA).