Tissue Factor Pathway Inhibitor Blocks Cellular Effects of Endotoxin by Binding to Endotoxin and Interfering With Transfer to CD14

Abstract Tissue factor pathway inhibitor (TFPI) is a Kunitz-type plasma protease inhibitor that inhibits factor Xa and the factor VIIa/tissue factor catalytic complex. It plays an important role in feedback inhibition of the coagulation cascade (Broze, Annu Rev Med 46:103, 1995). TFPI has also been used successfully to prevent lethality and attenuate coagulopathic responses in a baboon model of septic shock (Creasey et al, J Clin Invest 91:2850, 1993; and Carr et al, Circ Shock 44:126, 1995). However, the mechanism of reduced mortality in these animals could not be explained merely by the anticoagulant effect of TFPI, because TFPI-treated animals also had a significantly depressed interleukin-6 response. Moreover, inhibition of coagulopathic responses by other anticoagulants has failed to block the organ damage or lethal effect of endotoxic shock (Coalson et al, Circ Shock 5:423, 1978; Warr et al, Blood 75:1481, 1990; and Taylor et al, Blood 78:364, 1991). We show here that recombinant TFPI can bind to endotoxin in vitro. This binding prevents interaction of endotoxin with both lipopolysaccharide binding protein and CD14, thereby blocking cellular responses.

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Effect of Depolymerized Holothurian Glycosaminoglycan (DHG) on Tissue Factor Pathway Inhibitor: In Vitro and In Vivo Studies

Thrombosis and Haemostasis ◽

10.1055/s-0038-1657643 ◽

1997 ◽

Vol 78 (02) ◽

pp. 864-870 ◽

Cited By ~ 9

Author(s):

Hideki Nagase ◽

Kei-ichi Enjyoji ◽

Yu-ichi Kamikubo ◽

Keiko T Kitazato ◽

Kenji Kitazato ◽

...

Keyword(s):

Tissue Factor ◽

Tissue Factor Pathway Inhibitor ◽

Factor Xa ◽

Free Form ◽

Initial Reaction ◽

Extrinsic Pathway ◽

Factor Xa Inhibition ◽

Tissue Factor Pathway

SummaryDepolymerized holothurian glycosaminoglycan (DHG) is a glycosaminoglycan extracted from the sea cucumber Stichopus japonicusSelenka. In previous studies, we demonstrated that DHG has antithrombotic and anticoagulant activities that are distinguishable from those of heparin and dermatan sulfate. In the present study, we examined the effect of DHG on the tissue factor pathway inhibitor (TFPI), which inhibits the initial reaction of the tissue factor (TF)-mediated coagulation pathway. We first examined the effect of DHG on factor Xa inhibition by TFPI and the inhibition of TF-factor Vila by TFPI-factor Xa in in vitro experiments using human purified proteins. DHG increased the rate of factor Xa inhibition by TFPI, which was abolished either with a synthetic C-terminal peptide or with a synthetic K3 domain peptide of TFPI. In contrast, DHG reduced the rate of TF-factor Vila inhibition by TFPI-factor Xa. Therefore, the effect of DHG on in vitroactivity of TFPI appears to be contradictory. We then examined the effect of DHG on TFPI in cynomolgus monkeys and compared it with that of unfractionated heparin. DHG induced an increase in the circulating level of free-form TFPI in plasma about 20-fold when administered i.v. at 1 mg/kg. The prothrombin time (PT) in monkey plasma after DHG administration was longer than that estimated from the plasma concentrations of DHG. Therefore, free-form TFPI released by DHG seems to play an additive role in the anticoagulant mechanisms of DHG through the extrinsic pathway in vivo. From the results shown in the present work and in previous studies, we conclude that DHG shows anticoagulant activity at various stages of coagulation reactions, i.e., by inhibiting the initial reaction of the extrinsic pathway, by inhibiting the intrinsic Xase, and by inhibiting thrombin.

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TFPIβ is the GPI-anchored TFPI isoform on human endothelial cells and placental microsomes

Blood ◽

10.1182/blood-2011-10-388512 ◽

2012 ◽

Vol 119 (5) ◽

pp. 1256-1262 ◽

Cited By ~ 37

Author(s):

Thomas J. Girard ◽

Elodee Tuley ◽

George J. Broze

Keyword(s):

Endothelial Cells ◽

Tissue Factor ◽

Feedback Inhibition ◽

Culture Media ◽

Factor Viia ◽

Factor Xa ◽

Gpi Anchor ◽

C Terminus ◽

Before And After ◽

Tissue Factor Pathway

Abstract Tissue factor pathway inhibitor (TFPI) produces factor Xa-dependent feedback inhibition of factor VIIa/tissue factor-induced coagulation. Messages for 2 isoforms of TFPI have been identified. TFPIα mRNA encodes a protein with an acidic N-terminus, 3 Kunitz-type protease inhibitor domains and a basic C-terminus that has been purified from plasma and culture media. TFPIβ mRNA encodes a form in which the Kunitz-3 and C-terminal domains of TFPIα are replaced with an alternative C-terminus that directs the attachment of a glycosylphosphatidylinositol (GPI) anchor, but whether TFPIβ protein is actually expressed is not clear. Moreover, previous studies have suggested that the predominant form of TFPI released from cells by phosphatidylinositol-specific phospholipase C (PIPLC) treatment is TFPIα, implying it is bound at cell surfaces to a separate GPI-anchored coreceptor. Our studies show that the form of TFPI released by PIPLC treatment of cultured endothelial cells and placental microsomes is actually TFPIβ based on (1) migration on SDS-PAGE before and after deglycosylation, (2) the lack of a Kunitz-3 domain, and (3) it contains a GPI anchor. Immunoassays demonstrate that, although endothelial cells secrete TFPIα, greater than 95% of the TFPI released by PIPLC treatment from the surface of endothelial cells and from placental microsomes is TFPIβ.

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Recombinant full-length tissue factor pathway inhibitor fails to bind to the cell surface: implications for catabolism in vitro and in vivo

Blood ◽

10.1182/blood.v95.6.1973 ◽

2000 ◽

Vol 95 (6) ◽

pp. 1973-1978 ◽

Cited By ~ 7

Author(s):

Guyu Ho ◽

Masaaki Narita ◽

George J. Broze ◽

Alan L. Schwartz

Keyword(s):

Tissue Factor ◽

Tissue Factor Pathway Inhibitor ◽

Feedback Inhibition ◽

Factor Xa ◽

Full Length ◽

Pharmacokinetic Studies ◽

Dependent Manner ◽

Carboxy Terminus ◽

Tissue Factor Pathway

Abstract Tissue factor pathway inhibitor (TFPI) plays a key role in the regulation of tissue factor-initiated blood coagulation secondary to loss of the integrity of the blood vessel wall. TFPI is a naturally occurring Kunitz-type protease inhibitor that inhibits coagulation factor Xa and, in a factor Xa-dependent manner, mediates feedback inhibition of the factor VIIa/tissuefactor catalytic complex. In vivo full-length TFPI is thought to be primarily bound to the vascular endothelium and the high affinity binding requires an intact carboxy terminus. Here we describe a full-length TFPI molecule, expressed in mouse C127 cells (TFPIC127), which exhibits virtually no cellular binding yet contains the intact carboxy terminus. This TFPI (TFPIC127) is neither internalized nor degraded via the TFPI endocytic receptor, LDL-receptor–related protein. Pharmacokinetic studies of TFPIC127 in vivo demonstrate a 10-fold prolongation in the plasma half-life, compared with that of bacterial recombinant TFPI.

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Small Peptides Blocking Inhibition of Factor Xa and Tissue Factor-Factor VIIa by Tissue Factor Pathway Inhibitor (TFPI)

Journal of Biological Chemistry ◽

10.1074/jbc.m113.533836 ◽

2013 ◽

Vol 289 (3) ◽

pp. 1732-1741 ◽

Cited By ~ 28

Author(s):

Michael Dockal ◽

Rudolf Hartmann ◽

Markus Fries ◽

M. Christella L. G. D. Thomassen ◽

Alexandra Heinzmann ◽

...

Keyword(s):

Tissue Factor ◽

Tissue Factor Pathway Inhibitor ◽

Factor Viia ◽

Anticoagulant Activity ◽

Tight Binding ◽

Factor Xa ◽

Factor X ◽

Intermediate Segment ◽

Tissue Factor Pathway ◽

Α Helix

Tissue factor pathway inhibitor (TFPI) is a Kunitz-type protease inhibitor that inhibits activated factor X (FXa) via a slow-tight binding mechanism and tissue factor-activated FVII (TF-FVIIa) via formation of a quaternary FXa-TFPI-TF-FVIIa complex. Inhibition of TFPI enhances coagulation in hemophilia models. Using a library approach, we selected and subsequently optimized peptides that bind TFPI and block its anticoagulant activity. One peptide (termed compound 3), bound with high affinity to the Kunitz-1 (K1) domain of TFPI (Kd ∼1 nm). We solved the crystal structure of this peptide in complex with the K1 of TFPI at 2.55-Å resolution. The structure of compound 3 can be segmented into a N-terminal anchor; an Ω-shaped loop; an intermediate segment; a tight glycine-loop; and a C-terminal α-helix that is anchored to K1 at its reactive center loop and two-stranded β-sheet. The contact surface has an overall hydrophobic character with some charged hot spots. In a model system, compound 3 blocked FXa inhibition by TFPI (EC50 = 11 nm) and inhibition of TF-FVIIa-catalyzed FX activation by TFPI (EC50 = 2 nm). The peptide prevented transition from the loose to the tight FXa-TFPI complex, but did not affect formation of the loose FXa-TFPI complex. The K1 domain of TFPI binds and inhibits FVIIa and the K2 domain similarly inhibits FXa. Because compound 3 binds to K1, our data show that K1 is not only important for FVIIa inhibition but also for FXa inhibition, i.e. for the transition of the loose to the tight FXa-TFPI complex. This mode of action translates into normalization of coagulation of hemophilia plasmas. Compound 3 thus bears potential to prevent bleeding in hemophilia patients.

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Complementary DNA sequencing of canine tissue factor pathway inhibitor reveals a unique nanomeric repetitive sequence between the second and third Kunitz domains

Biochemical Journal ◽

10.1042/bj3030923 ◽

1994 ◽

Vol 303 (3) ◽

pp. 923-928 ◽

Cited By ~ 4

Author(s):

T J Girard ◽

D Gailani ◽

G J Broze

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Tissue Factor ◽

Tissue Factor Pathway Inhibitor ◽

Factor Viia ◽

Peptide Sequence ◽

Tissue Factor Pathway ◽

Kunitz Type ◽

Canine Plasma

Tissue factor pathway inhibitor (TFPI) is a factor Xa-dependent inhibitor of the factor VIIa-tissue factor complex of blood coagulation. The primary amino acid sequence of canine TFPI has been deduced from cDNA sequences obtained using the techniques of reverse transcription followed by amplification using PCR and conventional screening of a canine endothelial cell cDNA library. The open reading frame for canine TFPI encodes a signal peptide of 28 amino acids followed by a 40.7 kDa protein of 368 amino acids. Similar to human, rat and rabbit TFPI, canine TFPI contains a negatively-charged cluster of amino acids at its mature amino-terminus, followed by three Kunitz-type proteinase inhibitory domains and a cluster of positively-charged amino acids near its carboxy-terminus. In contrast to other TFPIs, following its second Kunitz-type proteinase inhibitory domain canine TFPI contains an additional amino acid insert which includes a nanomeric peptide-sequence repeated six times. Recombinant canine TFPI was expressed in both bacterial- and insect cell-expression systems for functional analysis and the generation of antibodies. The recombinant canine TFPI inhibits tissue factor-induced coagulation in an in vitro canine system. Immunoprecipitation of TFPI from canine plasma, followed by Western-blot analysis, tentatively identifies canine TFPI as an 80,000 kDa protein. Anti-peptide antibodies raised to the nanomeric peptide repeat immunoprecipitate an identical, cross-reactive, 80,000 kDa protein.

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Protein S enhances the tissue factor pathway inhibitor inhibition of factor Xa but not its inhibition of factor VIIa–tissue factor

Journal of Thrombosis and Haemostasis ◽

10.1111/j.1538-7836.2008.02980.x ◽

2008 ◽

Vol 6 (6) ◽

pp. 1044-1046 ◽

Cited By ~ 45

Author(s):

M. NDONWI ◽

G. BROZE

Keyword(s):

Tissue Factor ◽

Tissue Factor Pathway Inhibitor ◽

Factor Viia ◽

Factor Xa ◽

Protein S ◽

Tissue Factor Pathway

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Localization of tissue factor pathway inhibitor to lipid rafts is not required for inhibition of factor VIIa/tissue factor activity

Thrombosis and Haemostasis ◽

10.1055/s-0037-1613544 ◽

2003 ◽

Vol 89 (01) ◽

pp. 65-73 ◽

Cited By ~ 10

Author(s):

Garnet Jack ◽

Keith Page ◽

Tina Tetzloff ◽

Connie Hall ◽

Alan Mast ◽

...

Keyword(s):

Plasma Membrane ◽

Tissue Factor ◽

Lipid Rafts ◽

Tissue Factor Pathway Inhibitor ◽

Factor Viia ◽

Factor Xa ◽

Hek293 Cells ◽

Membrane Domains ◽

Gpi Anchor ◽

Tissue Factor Pathway

SummaryTissue factor pathway inhibitor (TFPI) abrogates coagulation initiated by the factor VIIa/tissue factor catalytic complex. While the gene structure of TFPI suggests that it is a secreted protein, a large pool of TFPI is associated with the vascular endothelium through its affinity for a glycosylphosphatidylinositol (GPI)-linked membrane protein. Inhibition of tissue factor by TFPI coincides with the translocation of quaternary complexes containing tissue factor, factor VIIa, factor Xa, and TFPI to detergent-insoluble plasma membrane domains rich in cholesterol, sphingomyelin, and GPI-linked proteins known as lipid rafts and caveolae. It is not known if localization of TFPI to these membrane domains is required for its inhibition of tissue factor procoagulant activity. We generated chimeric TFPI molecules linked directly to the plasma membrane via a GPI anchor or hydrophobic transmembrane domain and expressed these in HEK293 cells that produce tissue factor but not endogenous TFPI. The GPI-anchored chimera was exclusively enriched in detergent-insoluble membrane fractions while the transmembrane molecule was not. Transfectants expressing equal levels of the GPI-linked or transmembrane TFPI displayed equal anticoagulant potency as assessed by tissue factor-mediated conversion of factor X to factor Xa. Disruption of lipid rafts with cyclodextrin likewise had no effect on the inhibitory activity of the transmembrane or GPI-linked TFPI chimeras in HEK293 cells, nor on endogenous TFPI expressed by ECV304 cells. Thus, we conclude that the GPI anchor and membrane localization to lipid rafts does not enhance inhibition of factor VIIa/ tissue factor by cell-surface associated TFPI.

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Aptamer ARC19499 mediates a procoagulant hemostatic effect by inhibiting tissue factor pathway inhibitor

Blood ◽

10.1182/blood-2010-10-311936 ◽

2011 ◽

Vol 117 (20) ◽

pp. 5514-5522 ◽

Cited By ~ 87

Author(s):

Emily K. Waters ◽

Ryan M. Genga ◽

Michael C. Schwartz ◽

Jennifer A. Nelson ◽

Robert G. Schaub ◽

...

Keyword(s):

Tissue Factor ◽

Tissue Factor Pathway Inhibitor ◽

Hemophilia A ◽

Factor Viia ◽

Factor Xa ◽

Coagulation Factor ◽

Factor Ix ◽

Intrinsic Pathway ◽

Extrinsic Pathway ◽

Tissue Factor Pathway

Abstract Hemophilia A and B are caused by deficiencies in coagulation factor VIII (FVIII) and factor IX, respectively, resulting in deficient blood coagulation via the intrinsic pathway. The extrinsic coagulation pathway, mediated by factor VIIa and tissue factor (TF), remains intact but is negatively regulated by tissue factor pathway inhibitor (TFPI), which inhibits both factor VIIa and its product, factor Xa. This inhibition limits clot initiation via the extrinsic pathway, whereas factor deficiency in hemophilia limits clot propagation via the intrinsic pathway. ARC19499 is an aptamer that inhibits TFPI, thereby enabling clot initiation and propagation via the extrinsic pathway. The core aptamer binds tightly and specifically to TFPI. ARC19499 blocks TFPI inhibition of both factor Xa and the TF/factor VIIa complex. ARC19499 corrects thrombin generation in hemophilia A and B plasma and restores clotting in FVIII-neutralized whole blood. In the present study, using a monkey model of hemophilia, FVIII neutralization resulted in prolonged clotting times as measured by thromboelastography and prolonged saphenous-vein bleeding times, which are consistent with FVIII deficiency. ARC19499 restored thromboelastography clotting times to baseline levels and corrected bleeding times. These results demonstrate that ARC19499 inhibition of TFPI may be an effective alternative to current treatments of bleeding associated with hemophilia.

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Tissue factor pathway inhibitor: the carboxy-terminus is required for optimal inhibition of factor Xa

Blood ◽

10.1182/blood.v79.8.2004.2004 ◽

1992 ◽

Vol 79 (8) ◽

pp. 2004-2010 ◽

Cited By ~ 108

Author(s):

R Wesselschmidt ◽

K Likert ◽

T Girard ◽

TC Wun ◽

GJ Jr Broze

Keyword(s):

Tissue Factor ◽

Tissue Factor Pathway Inhibitor ◽

Factor Viia ◽

Factor Xa ◽

Reversible Inhibitor ◽

Normal Plasma ◽

Encounter Complex ◽

Factor Xa Inhibition ◽

Tissue Factor Pathway ◽

Inhibit Factor

Abstract Tissue factor pathway inhibitor (TFPI) is a multivalent Kunitz-type protease inhibitor that binds to and inactivates factor Xa directly, and in a factor Xa-dependent fashion inhibits the factor VIIa/tissue factor catalytic complex. TFPI is a slow, tight-binding, competitive, and reversible inhibitor of factor Xa, in which the formation of an initial encounter complex between TFPI and factor Xa is followed by slow isomerization to a final, tightened complex. Wild-type recombinant TFPI (rTFPI), expressed in mouse C127 cells, separates into two forms on heparin-agarose chromatography that elute at 0.3 mol/L and 0.6 mol/L NaCl. Western blot analysis shows that both forms contain the N- terminus of full-length TFPI, but only rTFPI(0.6) is recognized by an antibody directed against the C-terminus. rTFPI(0.3) and rTFPI(0.6) inhibit factor Xa with 1:1 stoichiometry and inhibit factor VIIa/tissue factor equally in an endpoint-type assay. However, rTFPI(0.6) is a more potent inhibitor than rTFPI(0.3) of coagulation in normal plasma induced by either factor Xa or tissue factor. The initial inhibition of factor Xa (less than 5 seconds) produced by rTFPI(0.6) is several-fold greater than that produced by rTFPI(0.3), presumably reflecting a lower Ki of the immediate encounter complex between factor Xa and TFPI. The differential effect of these forms of TFPI on tissue factor-induced coagulation in normal plasma appears to be directly related to their ability to inhibit factor Xa. To confirm the role of the C-terminal region of TFPI in optimal factor Xa inhibition, a carboxy-terminal mutant of rTFPI, which is truncated after leucine 252 and thus lacks the basic sequence K T K R K R K K Q R V K (residues 254–265), was expressed in C127 cells. This form of rTFPI elutes from heparin-agarose at 0.28 mol/L NaCl and inhibits factor Xa at a rate that is slower than rTFPI(0.3). The Ki(final)s for factor Xa inhibition by rTFPI(0.6), rTFPI(0.3), and rTFPI1–252 are 3.1 +/- 0.6, 19.6 +/- 0.8, and 19.6 +/- 3.0 pmol/L, respectively.

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