The C-terminus of tissue factor pathway inhibitor-α inhibits factor V activation by protecting the Arg1545cleavage site

SummaryTissue factor pathway inhibitor (TFPI) is a feed back inhibitor of the initial activation of the extrinsic pathway of coagulation. In humans, injection of heparin results in a 2-6 fold increase in plasma TFPI and recent studies suggest that TFPI may be important for the anticoagulant activity of heparin. Full length (FL) TFPI, but not recombinant two-domain (2D) TFPI, has a poly cationic C-terminus showing very strong heparin binding. Therefore, we have investigated if heparin affects the pharmacokinetics of TFPI with and without this C-terminus.FL-TFPI (608 U/kg) and 2D-TFPI (337 U/kg) were injected intravenously in rabbits with and without simultaneous intravenous injections of low molecular weight heparin (450 anti-XaU/kg).Heparin decreased the volume of distribution and the clearance of FL-TFPI by a factor 10-15, whereas the pharmacokinetics of 2D-TFPI were unaffected by heparin. When heparin was administered 2 h following TFPI the recovery of FL-TFPI was similar to that found in the group receiving the two compounds simultaneously, suggesting that the releasable pool of FL-TFPI is removed very slowly in the absence of circulating heparin.

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Factor Xa Enhances the Binding of Tissue Factor Pathway Inhibitor to Acidic Phospholipids

Thrombosis and Haemostasis ◽

10.1055/s-0038-1650369 ◽

1996 ◽

Vol 75 (05) ◽

pp. 796-800 ◽

Cited By ~ 10

Author(s):

Sanne Valentin ◽

Inger Schousboe

Keyword(s):

Tissue Factor ◽

Tissue Factor Pathway Inhibitor ◽

Factor Xa ◽

Microtitre Plate ◽

C Terminus ◽

Microtitre Plate Assay ◽

Kunitz Domain ◽

Tissue Factor Pathway ◽

Acidic Phospholipids

SummaryIn the present study, the interaction between tissue factor pathway inhibitor (TFPI) and phospholipids has been characterized using a microtitre plate assay. TFPI was shown to bind calcium-independently to an acidic phospholipid surface composed of phosphatidylserine, but not a surface composed of the neutral phosphatidylcholine. The interaction was demonstrated to be dependent on the presence of the TFPI C-terminus. The presence of heparin (1 U/ml, unfractionated) was able to significantly reduce the binding of TFPI to phospholipid. The interaction of TFPI with phosphatidylserine was significantly decreased in the presence of calcium, but this was counteracted, and even enhanced, following complex formation of TFPI with factor Xa prior to incubation with the phospholipid surface. Moreover, a TFPI variant, not containing the third Kunitz domain and the C-terminus, was unable to bind to phospholipid. However, following the formation of a TFPI/factor Xa-complex this TFPI variant was capable of interacting with the phospholipid surface. This indicates that the role of factor Xa as a TFPI cofactor, at least in part, is to mediate the binding of TFPI to the phospholipid surface.

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Elevated levels of tissue factor pathway inhibitor in patients with mild to moderate bleeding tendency

Blood Advances ◽

10.1182/bloodadvances.2020003464 ◽

2021 ◽

Vol 5 (2) ◽

pp. 391-398

Author(s):

Dino Mehic ◽

Alexander Tolios ◽

Stefanie Hofer ◽

Cihan Ay ◽

Helmuth Haslacher ◽

...

Keyword(s):

Tissue Factor ◽

Tissue Factor Pathway Inhibitor ◽

Genetic Alterations ◽

Factor V ◽

Bleeding Tendency ◽

Healthy Controls ◽

Single Nucleotide ◽

Time To Peak ◽

Coagulation Inhibitors ◽

Tissue Factor Pathway

Abstract High levels of tissue factor pathway inhibitor (TFPI), caused by a longer TFPIα half-life after binding to a factor V splice variant and variants in the F5 gene, were recently identified in 2 families with an as-yet-unexplained bleeding tendency. This study aimed to investigate free TFPIα in a well-characterized cohort of 620 patients with mild to moderate bleeding tendencies and its association to genetic alterations in the F5 gene. TFPIα levels were higher in patients with bleeding compared with healthy controls (median [interquartile range], 8.2 [5.5-11.7] vs 7.8 [4.3-11.1]; P = .026). A higher proportion of patients had free TFPIα levels more than or equal to the 95th percentile compared with healthy controls (odds ratio [OR] [95% confidence interval (CI)], 2.82 [0.98-8.13]). This was pronounced in the subgroup of patients in whom no bleeding disorder could be identified (bleeding of unknown cause [BUC; n = 420]; OR [95% CI], 3.03 [1.02-8.98]) and in platelet function defects (PFDs) (n = 121; OR [95% CI], 3.47 [1.09-11.08]). An increase in free TFPIα was associated with a mild delay in thrombin generation (prolonged lag time and time to peak), but not with alterations in routinely used global clotting tests. We could neither identify new or known genetic variations in the F5 gene that are associated with free TFPIα levels, nor an influence of the single-nucleotide variant rs10800453 on free TFPIα levels in our patient cohort. An imbalance of natural coagulation inhibitors such as TFPIα could be an underlying cause or contributor for unexplained bleeding, which is most probably multifactorial in a majority of patients.

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The interaction of factor V and tissue factor pathway inhibitor in a myeloma patient with acquired factor V deficiency

Haemophilia ◽

10.1111/hae.13492 ◽

2018 ◽

Vol 24 (3) ◽

pp. e160-e163 ◽

Cited By ~ 1

Author(s):

E. De Maertelaere ◽

E. Castoldi ◽

I. Van haute ◽

D. Deeren ◽

K. M. Devreese

Keyword(s):

Tissue Factor ◽

Tissue Factor Pathway Inhibitor ◽

Factor V ◽

Myeloma Patient ◽

Factor V Deficiency ◽

Tissue Factor Pathway

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Abstract 43: Prothrombinase Assembled with Factor V Leiden is Resistant to Inhibition by Tissue Factor Pathway Inhibitor α Lowering the Procoagulant Threshold for Initiation of Coagulation

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.36.suppl_1.43 ◽

2016 ◽

Vol 36 (suppl_1) ◽

Author(s):

Jeremy P Wood ◽

Lisa M Baumann Kreuziger ◽

Susan A Maroney ◽

Rodney M Camire ◽

Alan E Mast

Keyword(s):

Tissue Factor ◽

Thrombin Generation ◽

Tissue Factor Pathway Inhibitor ◽

Platelet Rich Plasma ◽

Anticoagulant Activity ◽

Factor V Leiden ◽

Factor Xa ◽

Factor V ◽

Activation Threshold ◽

Tissue Factor Pathway

Factor V (FV) assembles with factor Xa (FXa) into prothrombinase, the enzymatic complex that converts prothrombin to thrombin. Tissue factor pathway inhibitor α (TFPIα) inhibits prothrombinase by high affinity interactions with FXa-activated FV and the FXa active site, thereby blocking the initiation of coagulation. FV Leiden (FVL) is strongly linked to venous thrombosis through its resistance to degradation by activated protein C (aPC), which enhances the propagation of coagulation. FVL combined with a 50% reduction in TFPI causes severe thrombosis and perinatal lethality in mice, suggesting that FVL also promotes the initiation of coagulation. To examine this possibility, thrombin generation assays initiated with limiting FXa were performed with control or FVL plasma and platelet-rich plasma (PRP). The activation threshold for thrombin generation was 10 to 20 pM FXa in 10 control plasmas, but was 5 pM in 4 of 10 homozygous FVL plasmas. FVL PRP had a similar decrease in the activation threshold. The differences in activation threshold were totally normalized by an anti-TFPI antibody, while exogenous TFPIα and a FV-binding peptide that mimics TFPIα had reduced anticoagulant activity in FVL plasma, revealing that the procoagulant effects of FVL in these assays rely on TFPIα. Next, FVL plasmas were studied in fibrin clot formation assays, as they are sensitive to small amounts of thrombin. In reactions activated with 0.5 pM FXa, 1 of 8 control plasmas, compared to 7 of 8 homozygous FVL plasmas, clotted within 60 minutes, with differences again normalized by the anti-TFPI antibody. In prothrombinase activity assays using purified proteins, TFPIα was a 1.7-fold weaker inhibitor of prothrombinase assembled with FVL compared to FV. Thus, in addition to its aPC-mediated effect on the propagation of coagulation, FVL is resistant to TFPIα inhibition, exerting a procoagulant effect on coagulation initiation. This is evident in responses to small stimuli, where TFPIα blocks clotting in plasmas with FV but not FVL. The TFPIα-mediated modulation of the procoagulant threshold may explain the severe perinatal thrombosis in FVL mice with decreased TFPI and be clinically relevant in the clotting associated with oral contraceptives, which cause acquired TFPI deficiency.

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Evidence that the C-terminus of tissue factor pathway inhibitor (TFPI) is essential for its in vitro and in vivo interaction with lipoproteins

Blood Coagulation & Fibrinolysis ◽

10.1097/00001721-199310000-00007 ◽

1993 ◽

Vol 4 (5) ◽

pp. 713-720

Author(s):

S. Valentin ◽

O. Nordfang ◽

C. Bregengård ◽

P. Wildgoose

Keyword(s):

Tissue Factor ◽

Tissue Factor Pathway Inhibitor ◽

C Terminus ◽

Tissue Factor Pathway

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The C536T Transition in the Tissue Factor Pathway Inhibitor (TFPI) Gene Does not Contribute to Risk of Venous Thrombosis among Carriers of Factor V Leiden

Thrombosis and Haemostasis ◽

10.1055/s-0037-1614095 ◽

2000 ◽

Vol 84 (10) ◽

pp. 724-725 ◽

Cited By ~ 6

Author(s):

Robert Luhm ◽

Martin Hessner

Keyword(s):

Venous Thrombosis ◽

Tissue Factor ◽

Tissue Factor Pathway Inhibitor ◽

Factor V Leiden ◽

Factor V ◽

Tissue Factor Pathway

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Interaction between tissue factor pathway inhibitor and factor V levels on the risk of venous thrombosis

Journal of Thrombosis and Haemostasis ◽

10.1111/j.1538-7836.2010.03805.x ◽

2010 ◽

Author(s):

A. E. A. Dahm ◽

I. D. Bezemer ◽

P. M. Sandset ◽

F. R. Rosendaal

Keyword(s):

Venous Thrombosis ◽

Tissue Factor ◽

Tissue Factor Pathway Inhibitor ◽

Factor V ◽

Tissue Factor Pathway

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Procoagulant Activity of Laminaria Japonica Derived Fucoidan (BAX513) Depends on the Interaction with the C-Terminus of Tissue Factor Pathway Inhibitor

Blood ◽

10.1182/blood.v116.21.4417.4417 ◽

2010 ◽

Vol 116 (21) ◽

pp. 4417-4417 ◽

Cited By ~ 1

Author(s):

Michael Palige ◽

Christoph Redl ◽

Sabine Knappe ◽

Hartmut J. Ehrlich ◽

Michael Dockal ◽

...

Keyword(s):

Tissue Factor ◽

Mechanism Of Action ◽

Thrombin Generation ◽

Tissue Factor Pathway Inhibitor ◽

Laminaria Japonica ◽

Full Length ◽

Procoagulant Activity ◽

C Terminus ◽

Tissue Factor Pathway ◽

Dose Dependent

Abstract Abstract 4417 BAX513, a fucoidan derived from the brown seaweed Laminaria japonica, and other non-anticoagulant sulfated polysaccharides (NASPs) improve coagulation in hemophilic blood and plasma. Fucoidans are heterogeneous, polysulfated molecules with procoagulant activities in a wide concentration range. Tissue factor pathway inhibitor (TFPI) has been described as a potential target for the procoagulant activity of NASPs (Liu et al. Thromb Haemost 2006; 95:68). In the current study, we investigated the interaction of BAX513 with TFPI proteins to gain a detailed understanding of the mechanism of action of BAX513. We used calibrated automated thrombography to monitor the activity of BAX513 in normal, FX and TFPI-deficient plasma. TFPI plasma levels were varied by the addition of truncated TFPI (TFPI1-160) and TFPI-domain specific antibodies. Initiating thrombin generation by addition of FXa to plasma deficient in both, FX and FVIII-showed a BAX513-dose dependent increase of thrombin generation, which was completely abolished when TFPI-specific polyclonal antibodies were present. Furthermore, when full-length TFPI was inhibited in plasma and instead supplemented with increasing amounts of TFPI 1–160, BAX513 did not show any activity. The data are further supported by surface plasmon resonance experiments (BiaCore) exploring the BAX513-TFPI interaction. A high affinity interaction was only observed for BAX513 with full-length TFPI but not for BAX513 with TFPI1-160. Our findings support a mechanism of action in which BAX513 acts as a potent dose-dependent TFPI antagonist that requires the highly charged C-terminus of TFPI to unfold its full potential. Understanding the mechanism of action of BAX513 supports the development of BAX513 as a promising new therapeutic for hemophiliacs and FVIII-inhibitor patients. Disclosures: Palige: Baxter Innovations GmbH: Employment. Redl:Baxter Innovations GmbH: Employment. Knappe:Baxter Innovations GmbH: Employment. Ehrlich:Baxter Innovations GmbH: Employment. Dockal:Baxter Innovations GmbH: Employment. Scheiflinger:Baxter Innovations GmbH: Employment.

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