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Ahnström J, Petri A, Crawley JTB. Tissue factor pathway inhibitor - cofactor-dependent regulation of the initiation of coagulation. Curr Opin Hematol 2024; 31:315-320. [PMID: 39259668 PMCID: PMC11426987 DOI: 10.1097/moh.0000000000000838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/13/2024]
Abstract
PURPOSE OF REVIEW In humans, tissue factor pathway inhibitor (TFPI) exists in two alternatively spliced isoforms, TFPIα and TFPIβ. TFPIα consists of three Kunitz domains (K1, K2 and K3) and a highly basic C-terminal tail. K1 inhibits the tissue factor-activated factor VII complex, K2 specifically inhibits activated factor X, K3 is essential for interaction with its cofactor, protein S, and the basic C-terminus is binds factor V-short (FV-short) with high affinity. TFPIβ consists of K1 and K2 that is glycosylphosphatidylinositol anchored directly to cell surfaces. This review explores the structure/function of TFPI and its cofactors (protein S and FV-short), and the relative contributions that different TFPI isoforms may play in haemostatic control. RECENT FINDINGS Recent data have underscored the importance of TFPIα function and its reliance on its cofactors, protein S and FV-short, in influencing haemostatic control as well as bleeding and thrombotic risk. SUMMARY TFPIα is likely the most important pool of TFPI in modifying the risk of thrombosis and bleeding. TFPIα forms a trimolecular complex with FV-short and protein S in plasma. FV-short expression levels control the circulating levels of TFPIα, whereas protein S exerts essential cofactor mediated augmentation of it anticoagulant function.
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Affiliation(s)
- Josefin Ahnström
- Centre for Haematology, Department of Immunology and Inflammation, Hammersmith Hospital Campus, Imperial College London, London, UK
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2
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Eldem I, Antunes-Heck L, Subramanian R, Lasky NM, Ashworth K, Di Paola J, Girard TJ. Deletion of tissue factor pathway inhibitor isoform beta or gamma, but not alpha, improves clotting in hemophilic mice. J Thromb Haemost 2024; 22:2681-2691. [PMID: 38925489 DOI: 10.1016/j.jtha.2024.06.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 06/06/2024] [Accepted: 06/07/2024] [Indexed: 06/28/2024]
Abstract
BACKGROUND Tissue factor pathway inhibitor (TFPI) regulates tissue factor-triggered coagulation. Humans and mice express transcripts encoding for multidistributed (endothelial, platelet, and plasma) 3-Kunitz domain TFPIα and endothelial membrane-anchored 2-Kunitz TFPIβ. Mice express a third transcript, γ, that encodes plasma lipoprotein-associated 2-Kunitz TFPI. In humans, proteolysis of α and/or β produces plasma lipoprotein-associated 2-Kunitz TFPI at lower levels. In clinical trials, monoclonal antibodies that target all TFPI isoforms extend coagulation and correct bleeding in hemophilic patients but with some thrombosis risks. OBJECTIVES To determine the impact of TFPI isoform-specific deletions on promoting clotting in hemophilic mice. METHODS Engineered TFPI isoform-specific, hemophilic (factor VIII-null) mice were evaluated for clotting. RESULTS Mice expressing any single TFPI isoform were healthy. Thrombin generation assays identified TFPIγ as the dominant anticoagulation isoform in mouse plasma. Hemostasis was assessed by serial bleeding times from a tail vein laceration. Repeatedly, after a clot forms, it was manually disrupted; the number of clots/disruptions occurring over a 15-minute period were reported. C57BL/6 and hemophilic mice clot on average 25.6 vs 5.4 times, respectively. On a hemophilia background, TFPIβ or TFPIγ-specific deletion improved clotting to 14.6 and 15.2 times, respectively (P < .0001). TFPIα-specific deletion was without impact, clotting 5.1 times. Heterozygous deletion of TFPIβ was effective, clotting 11.8 times (P < .0001). Heterozygous deletion of TFPIα or TFPIγ alone was ineffective, clotting 3.0 and 6.1 times, respectively, but heterozygous TFPIαγ deletion improved clotting to 11.2 times (P < .001). CONCLUSION In hemophilic mice, endothelial TFPIβ and plasma γ-derived 2-Kunitz TFPI individually contribute more to bleeding than total TFPIα.
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Affiliation(s)
- Irem Eldem
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Lilian Antunes-Heck
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Renumathi Subramanian
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Nina M Lasky
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Katrina Ashworth
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Jorge Di Paola
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, USA.
| | - Thomas J Girard
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, USA.
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Mehic D, Schramm T, Forstner-Bergauer B, Haslacher H, Ay C, Pabinger I, Gebhart J. Activated protein C and free protein S in patients with mild to moderate bleeding disorders. Thromb Res 2024; 235:98-106. [PMID: 38324941 DOI: 10.1016/j.thromres.2024.01.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 11/29/2023] [Accepted: 01/22/2024] [Indexed: 02/09/2024]
Abstract
BACKGROUND Underlying mechanisms for bleeding and impaired thrombin generation (TG) and plasma clot formation (PCF) in patients with mild to moderate bleeding disorders (MBDs) are still to be elucidated, especially in bleeding disorder of unknown cause (BDUC). The role of the natural anticoagulants activated protein C (APC) and free protein S (PS) has not yet been investigated in this patient population. AIMS To analyze antigen levels of APC and PS in patients with MBDs and BDUC and investigate associations to clinical bleeding phenotype and severity as well as and hemostatic capacity. METHODS Antigen levels of APC and free PS were measured in 262 patients from the Vienna Bleeding Biobank (VIBB), a single-center cohort study, by ELISA and compared to 61 healthy controls (HC). RESULTS Antigen levels of APC were higher in MBD patients than in HC when adjusted for age, sex and BMI (median (IQR) 33.1 (20.6-52.6) and 28.6 (16.4-47.2) ng/mL). This was most pronounced in patients with BDUC (35.3 (21.7-54.3) ng/mL). No differences in PS antigen levels between patients and HC were seen overall, or according to specific diagnoses. Further, no association between APC or PS and bleeding severity or global tests of hemostasis or TG were identified, while paradoxically APC weakly correlated with shorter lag time and time to peak of PCF in BDUC. CONCLUSION Our data demonstrate increased antigen levels of APC in BDUC, which might contribute to the bleeding tendency in some patients and could be a future therapeutic target in BDUC.
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Affiliation(s)
- Dino Mehic
- Clinical Division of Hematology and Hemostaseology, Department of Medicine I, Medical University of Vienna, Vienna, Austria
| | - Theresa Schramm
- Clinical Division of Hematology and Hemostaseology, Department of Medicine I, Medical University of Vienna, Vienna, Austria
| | - Birgit Forstner-Bergauer
- Clinical Division of Hematology and Hemostaseology, Department of Medicine I, Medical University of Vienna, Vienna, Austria
| | - Helmuth Haslacher
- Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria
| | - Cihan Ay
- Clinical Division of Hematology and Hemostaseology, Department of Medicine I, Medical University of Vienna, Vienna, Austria
| | - Ingrid Pabinger
- Clinical Division of Hematology and Hemostaseology, Department of Medicine I, Medical University of Vienna, Vienna, Austria
| | - Johanna Gebhart
- Clinical Division of Hematology and Hemostaseology, Department of Medicine I, Medical University of Vienna, Vienna, Austria.
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4
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Mohapatra AK, Todaro AM, Castoldi E. Factor V variants in bleeding and thrombosis. Res Pract Thromb Haemost 2024; 8:102330. [PMID: 38404937 PMCID: PMC10883835 DOI: 10.1016/j.rpth.2024.102330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 01/04/2024] [Indexed: 02/27/2024] Open
Abstract
A state-of-the-art lecture titled "Factor V variants in bleeding and thrombosis" was presented at the International Society on Thrombosis and Haemostasis (ISTH) congress in 2023. Blood coagulation is a finely regulated cascade of enzymatic reactions culminating in thrombin formation and fibrin deposition at the site of injury. Factor V (FV) plays a central role in this process, as its activated form is an essential procoagulant cofactor in prothrombin activation. However, other molecular forms of FV act as anticoagulant cofactors of activated protein C and tissue factor pathway inhibitor α, respectively, thereby contributing to the regulation of coagulation. This dual procoagulant and anticoagulant character makes FV a central regulator of the hemostatic balance, and quantitative and qualitative alterations of FV may be associated with an increased risk of bleeding or venous thrombosis. Here, we review the procoagulant and anticoagulant functions of FV and the manifold mechanisms by which F5 gene mutations may affect the balance between these opposite functions and thereby predispose individuals to bleeding or venous thrombosis. In particular, we discuss our current understanding of the 3 main pathological conditions related to FV, namely FV deficiency, activated protein C resistance, and the overexpression of FV-short, a minor splicing isoform of FV with tissue factor pathway inhibitor α-dependent anticoagulant properties and an emerging role as a key regulator of the initiation of coagulation. Finally, we summarize relevant new data on this topic presented during the 2023 ISTH Congress.
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Affiliation(s)
- Adarsh K. Mohapatra
- Department of Biochemistry, CARIM, Maastricht University, Maastricht, the Netherlands
| | - Alice M. Todaro
- Department of Biochemistry, CARIM, Maastricht University, Maastricht, the Netherlands
| | - Elisabetta Castoldi
- Department of Biochemistry, CARIM, Maastricht University, Maastricht, the Netherlands
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Mathews N, Tasneem S, Hayward CPM. Rare inherited coagulation and fibrinolytic defects that challenge diagnostic laboratories. Int J Lab Hematol 2023. [PMID: 37211424 DOI: 10.1111/ijlh.14084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 04/12/2023] [Indexed: 05/23/2023]
Abstract
BACKGROUND Coagulation factors, anticoagulants, and fibrinolytic proteins are important for hemostasis, and mutations affecting these proteins causes some rare inherited bleeding disorders that are particularly challenging to diagnose. AIMS This review provides current information on rare inherited bleeding disorders that are difficult to diagnose. MATERIAL & METHODS A review of the literature was conducted for up to date information on rare and difficult to diagnose bleeding disorders. RESULTS Some rare bleeding disorders cause an inherited deficiency of multiple coagulation factors (F), such as combined FV and FVIII deficiency and familial vitamin K-dependent clotting factor deficiency. Additionally, congenital disorders of glycosylation can affect a variety of procoagulant and anticoagulant proteins and also platelets. Some bleeding disorders reflect mutations with unique impairments in the procoagulant/anticoagulant balance, including those caused by F5 mutations that secondarily increase the plasma levels of tissue factor pathway inhibitor as well as THBD mutations that increase functional thrombomodulin in plasma or cause a consumptive coagulopathy due to thrombomodulin deficiency. Some bleeding disorders accelerate fibrinolysis due to loss-of-function mutations in SERPINE1 and SERPINF2 or in the case of Quebec platelet disorder, a duplication mutation that rewires PLAU and selectively increases expression in megakaryocytes, resulting in a unique platelet-dependent gain-of-function defect in fibrinolysis. DISCUSSION Current information on rare and difficult to diagnose bleeding disorders indicates they have unique clinical and laboratory features, and pathogenic characteristics to consider for diagnostic evaluation. CONCLUSION Laboratories and clinicians should consider rare inherited disorders, and difficult to diagnose conditions, in their strategy for diagnosing bleeding disorders.
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Affiliation(s)
- Natalie Mathews
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
- Hamilton Regional Laboratory Medicine Program, Hamilton, Ontario, Canada
| | - Subia Tasneem
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Catherine P M Hayward
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
- Hamilton Regional Laboratory Medicine Program, Hamilton, Ontario, Canada
- Department of Medicine, McMaster University, Hamilton, Ontario, Canada
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Maroney SA, Siebert AE, Martinez ND, Rasmussen M, Peterson JA, Weiler H, Lincoln J, Mast AE. Platelet tissue factor pathway inhibitor-α dampens cardiac thrombosis and associated fibrosis in mice. J Thromb Haemost 2023; 21:639-651. [PMID: 36696221 PMCID: PMC10200073 DOI: 10.1016/j.jtha.2022.11.034] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 11/17/2022] [Accepted: 11/28/2022] [Indexed: 01/21/2023]
Abstract
BACKGROUND Tissue factor pathway inhibitor (TFPI) is the primary inhibitor of events initiating the blood coagulation pathway. Tfpi-/- mice die during embryonic development. The absence of protease-activated receptor (PAR) 4, the major thrombin receptor on mouse platelets, rescues Tfpi-/-mice to adulthood. Among the 3 TFPI isoforms in mice, TFPIα is the only isoform within platelets (pltTFPIα) and the only isoform that inhibits prothrombinase, the enzymatic complex that converts prothrombin to thrombin. OBJECTIVES To determine biological functions of pltTFPIα. METHODS Tfpi-/-/Par4-/- mice were irradiated and transplanted with bone marrow from mice lacking or containing pltTFPIα. Thus, PAR4 expression was restored in the recipient mice, which differed selectively by the presence or absence of pltTFPIα and lacked other forms of TFPI. RESULTS Recipient mice lacking pltTFPIα had reduced survival over the 200-day posttransplant period. Necropsy revealed radiation injury associated with large intraventricular platelet-rich thrombi, whereas other organs were not affected. Thrombi were associated with fibrotic presentations, including increased collagen deposition, periostin-positive activated fibroblasts, myofibroblasts, and macrophage infiltrates. Recipient mice containing pltTFPIα showed evidence of radiation injury but lacked heart pathology. CONCLUSIONS Tfpi-/-/Par4-/- mice develop severe cardiac fibrosis following irradiation and transplantation with bone marrow lacking pltTFPIα. This pathology is markedly reduced when the mice are transplanted with bone marrow containing pltTFPIα. Thus, in this model system pltTFPIα has an important physiological role in dampening pathological responses mediated by activated platelets within the heart tissue.
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Affiliation(s)
- Susan A Maroney
- Thrombosis and Hemostasis Program, Versiti Blood Research Institute, Milwaukee, WI, USA
| | - Amy E Siebert
- Thrombosis and Hemostasis Program, Versiti Blood Research Institute, Milwaukee, WI, USA
| | - Nicholas D Martinez
- Thrombosis and Hemostasis Program, Versiti Blood Research Institute, Milwaukee, WI, USA
| | - Mark Rasmussen
- Thrombosis and Hemostasis Program, Versiti Blood Research Institute, Milwaukee, WI, USA
| | - Julie A Peterson
- Thrombosis and Hemostasis Program, Versiti Blood Research Institute, Milwaukee, WI, USA
| | - Hartmut Weiler
- Thrombosis and Hemostasis Program, Versiti Blood Research Institute, Milwaukee, WI, USA; Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Joy Lincoln
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, USA; Division of Pediatric Cardiology, The Herma Heart Institute, Children's Wisconsin, Milwaukee, WI, USA
| | - Alan E Mast
- Thrombosis and Hemostasis Program, Versiti Blood Research Institute, Milwaukee, WI, USA; Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA.
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7
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Reitsma SE, Holle LA, Bouck EG, Monroe DM, Mast AE, Burthem J, Bolton-Maggs PHB, Gidley GN, Wolberg AS. Tissue factor pathway inhibitor is a potential modifier of bleeding risk in factor XI deficiency. J Thromb Haemost 2023; 21:467-479. [PMID: 36696199 PMCID: PMC10111213 DOI: 10.1016/j.jtha.2022.10.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 09/26/2022] [Accepted: 10/06/2022] [Indexed: 01/26/2023]
Abstract
BACKGROUND Factor (F) XI deficiency is associated with increased bleeding risk in some individuals. Neither FXI levels nor clinical clotting assays predict the bleeding risk. Compared with controls, FXI-deficient bleeders have reduced clot formation, decreased fibrin network density, and increased susceptibility to fibrinolysis. Tissue factor pathway inhibitor (TFPI) was recently implicated as a modifying factor in individuals with bleeding of unknown cause. OBJECTIVES To determine the potential of TFPI in modifying the bleeding risk in FXI-deficient individuals. METHODS The effects of TFPI on thrombin generation and clot formation, structure, and fibrinolysis in FXI-deficient plasma were measured in vitro in the absence or presence of inhibitory anti-TFPI antibody or exogenous recombinant TFPIα. Total plasma TFPI concentration was measured in 2 independent cohorts of controls and FXI-deficient individuals classified as bleeders or nonbleeders (cohort 1: 10 controls and 16 FXI-deficient individuals; cohort 2: 48 controls and 57 FXI-deficient individuals) and correlated with ex vivo plasma clot formation and fibrinolysis parameters associated with bleeding risk. RESULTS In an in vitro FXI deficiency model, inhibition of TFPI enhanced thrombin generation and clot formation, increased the network density, and decreased fibrinolysis, whereas an increase in TFPI had the opposite effects. Compared with controls, plasma from FXI-deficient bleeders had higher TFPI concentration. Total plasma TFPI concentrations correlated with parameters from ex vivo clotting and fibrinolysis assays that differentiate FXI-deficient bleeders and nonbleeders. CONCLUSION Coagulation and fibrinolysis parameters that differentiate FXI-deficient nonbleeders and bleeders were altered by plasma TFPIα. Total plasma TFPI was increased in FXI-deficient bleeders. TFPI may modify the bleeding risk in FXI-deficient individuals.
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Affiliation(s)
- Stéphanie E Reitsma
- Department of Pathology and Laboratory Medicine and UNC Blood Research Center, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Lori A Holle
- Department of Pathology and Laboratory Medicine and UNC Blood Research Center, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Emma G Bouck
- Department of Pathology and Laboratory Medicine and UNC Blood Research Center, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Dougald M Monroe
- Department of Medicine and UNC Blood Research Center, University of North Carolina at Chapel Hill, North Carolina, USA
| | - Alan E Mast
- Versiti Blood Research Institute, Milwaukee, Wisconsin, USA
| | - John Burthem
- Department of Haematology, Manchester Royal Infirmary, Manchester University NHS Foundation Trust, Manchester, UK; Institute of Cancer Sciences, The University of Manchester, Manchester, UK
| | | | - Gillian N Gidley
- Institute of Cancer Sciences, The University of Manchester, Manchester, UK; Department of Haematology, St James' Hospital, Leeds Teaching Hospitals Trust, UK
| | - Alisa S Wolberg
- Department of Pathology and Laboratory Medicine and UNC Blood Research Center, University of North Carolina, Chapel Hill, North Carolina, USA.
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8
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Dahlbäck B. Natural anticoagulant discovery, the gift that keeps on giving: finding FV-Short. J Thromb Haemost 2023; 21:716-727. [PMID: 36746318 DOI: 10.1016/j.jtha.2023.01.033] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 01/24/2023] [Accepted: 01/24/2023] [Indexed: 02/05/2023]
Abstract
The complex reactions of blood coagulation are balanced by several natural anticoagulants resulting in tuned hemostasis. During several decades, the knowledge base of the natural anticoagulants has greatly increased and we have also learned about antiinflammatory and cytoprotective activities expressed by antithrombin and activated protein C (APC). Some coagulation proteins have also been found to function as anticoagulants; e.g., thrombin when bound to thrombomodulin activates protein C. Another example is factor V (FV), which in addition to being a procofactor to FVa has emerged as an anticoagulant. The discovery of APC resistance, caused by FVLeiden, as a thrombosis risk factor resulted in the identification of FV as an APC cofactor working in synergy with protein S in the regulation of FVIIIa in the Xase complex. More recently, a natural anticoagulant FV splice isoform (FV-Short) was discovered when investigating the East Texas bleeding disorder. In FV-Short, the truncated B domain exposes a high-affinity binding site for tissue factor pathway inhibitor alpha (TFPIα), and together with protein S a high-affinity trimolecular complex is generated. The FXa-inhibitory activity of TFPIα is synergistically stimulated by FV-Short and protein S. The circulating FV-Short/protein S/TFPIα complex concentration is normally low (≈0.2 nM) but provides an anticoagulant threshold. In the East Texas bleeding, the concentration of the complex, and thus the threshold, is increased 10-fold, which results in bleeding manifestations. The anticoagulant properties of FV were discovered during investigations of individual patients and follow the great tradition of bed-to-bench and bench-to-bed research in the coagulation field.
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Affiliation(s)
- Björn Dahlbäck
- Department of Translational Medicine, University Hospital, Lund University, 21428 Malmö, Sweden.
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9
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Ayombil F, Petrillo T, Kim H, Camire RM. Regulation of Factor V by the Anticoagulant Protease Activated Protein C: Influence of the B-domain and TFPIα. J Biol Chem 2022; 298:102558. [DOI: 10.1016/j.jbc.2022.102558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 09/25/2022] [Accepted: 09/26/2022] [Indexed: 10/14/2022] Open
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10
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Samelson-Jones BJ. A new harmony for hemorrhagic disorders: The Dutch SYMPHONY consortium. J Thromb Haemost 2022; 20:1984-1985. [PMID: 35968793 DOI: 10.1111/jth.15786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 06/08/2022] [Accepted: 06/11/2022] [Indexed: 11/29/2022]
Affiliation(s)
- Benjamin J Samelson-Jones
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- The Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Division of Hematology, Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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11
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Mast AE, Ruf W. Regulation of coagulation by tissue factor pathway inhibitor: Implications for hemophilia therapy. J Thromb Haemost 2022; 20:1290-1300. [PMID: 35279938 PMCID: PMC9314982 DOI: 10.1111/jth.15697] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 02/08/2022] [Accepted: 03/07/2022] [Indexed: 11/27/2022]
Abstract
Tissue factor pathway inhibitor (TFPI) is an alternatively spliced anticoagulant protein that primarily dampens the initiation phase of coagulation before thrombin is generated. As such, TFPI's actions are localized to cells expressing TF and to sites of injury, where it is an important regulator of bleeding in hemophilia. The major splice isoforms TFPIα and TFPIβ localize to different sites within and surrounding the vasculature. Both forms directly inhibit factor Xa (FXa) via their Kunitz 2 domain and inhibit TF-FVIIa via their Kunitz 1 domain in a tight complex primarily localized to cells. By forming complexes localized to distinct cellular microenvironments and engaging additional cell surface receptors, TFPI alters cellular trafficking and signaling pathways driven by coagulation proteases of the TF pathway. TFPIα, which circulates in complex with FV and protein S, also serves an inhibitor of FXa independent of the TF initiation complex and prevents the formation of an active prothrombinase. This regulation of thrombin generation in the context of vessel injury is effectively blocked by antibodies to Kunitz 2 domain of TFPI and exploited as a therapy to restore efficient hemostasis in hemophilia.
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Affiliation(s)
- Alan E. Mast
- Versiti Blood Research InstituteMilwaukeeWisconsinUSA
| | - Wolfram Ruf
- Center for Thrombosis and HemostasisJohannes Gutenberg University Medical CenterMainzGermany
- Department of Immunology and MicrobiologyScripps ResearchLa JollaCaliforniaUSA
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12
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Dahlbäck B, Tran S. A hydrophobic patch (PLVIVG; 1481-1486) in the B-domain of factor V-short is crucial for its synergistic TFPIα-cofactor activity with protein S and for the formation of the FXa-inhibitory complex comprising FV-short, TFPIα, and protein S. J Thromb Haemost 2022; 20:1146-1157. [PMID: 35247027 PMCID: PMC9313797 DOI: 10.1111/jth.15690] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 02/09/2022] [Accepted: 02/25/2022] [Indexed: 11/28/2022]
Abstract
BACKGROUND Factor V-short (FV756-1458) is a natural splice variant functioning in synergy with protein S as tissue factor pathway inhibitor alpha (TFPIα)-cofactor in inhibition of factor Xa (FXa). An exposed acid region (AR2; 1493-1537) in the B domain binds TFPIα. The preAR2 (1458-1492) is crucial for the synergistic TFPIα-cofactor activity between FV-short and protein S and for assembly of a trimolecular FXa-inhibitory complex among FV-short, protein S, and TFPIα. OBJECTIVE To identify which part of preAR2 is required for the synergistic TFPIα-cofactor activity between FV-short and protein S. METHODS A FXa-inhibition assay was used to test the synergistic TFPIα cofactor activity between protein S and new FV-short variants FV709-1476, FV712-1478, FV712-1481, FV712-1484, FV712-1487, and FV712-1490. A microtiter-based assay analyzed binding among FV-short variants, protein S, and TFPIα. RESULTS FV709-1476, FV712-1478, and FV712-1481 were fully active as synergistic TFPIα cofactors with protein S; FV712-1484 showed intermediate activity; and FV712-1487 and FV712-1490 were inactive. TFPIα interacted with all variants in the absence of protein S but FV712-1478 and FV712-1481 bound TFPIα with highest affinity. None of the FV-short variants bound directly to protein S in the absence of TFPIα. In the presence of TFPIα, efficient cooperative binding was demonstrated between protein S, TFPIα, and FV709-1476, FV712-1478, or FV712-1481. In contrast, no cooperativity among TFPIα, protein S, and FV712-1484, FV712-1487, or FV712-1490 was seen. CONCLUSION A short hydrophobic patch in preAR2 (PLVIVG, 1481-1486) in FV-short is crucial for the synergistic TFPIα-cofactor activity between FV-short and protein S and for the assembly of a trimolecular FXa-inhibitory complex among FV-short, protein S, and TFPIα.
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Affiliation(s)
- Björn Dahlbäck
- Department of Translational MedicineUniversity HospitalLund UniversityMalmöSweden
| | - Sinh Tran
- Department of Translational MedicineUniversity HospitalLund UniversityMalmöSweden
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13
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Peterson JA, Gupta S, Martinez ND, Hardesty B, Maroney SA, Mast AE. Factor V east Texas variant causes bleeding in a three-generation family. J Thromb Haemost 2022; 20:565-573. [PMID: 34847292 PMCID: PMC8885967 DOI: 10.1111/jth.15612] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 11/11/2021] [Accepted: 11/29/2021] [Indexed: 12/30/2022]
Abstract
BACKGROUND The factor V east Texas bleeding disorder (FVETBD) is caused by increased plasma tissue factor pathway inhibitor-α (TFPIα) concentration. The underlying cause is a variant in F5 causing alternative splicing within exon 13 and producing FV-short, which tightly binds the C-terminus of TFPIα, prolonging its circulatory half-life. OBJECTIVES To diagnose a family presenting with variable bleeding and laboratory phenotypes. PATIENTS/METHODS Samples were obtained from 17 family members for F5 exon 13 sequencing. Plasma/platelet TFPI and platelet FV were measured by ELISA and/or western blot. Plasma thrombin generation potential was evaluated using calibrated automated thrombography. RESULTS The FVET variant was identified in all family members with bleeding symptoms and associated with elevated plasma TFPIα (4.5- to 13.4-fold) and total TFPI (2- to 3-fold). However, TFPIα and FV-short were not elevated in platelets. TF-initiated thrombin generation in patient plasma was diminished but was restored by a monoclonal anti-TFPI antibody or factor VIIa. TFPIα localized within vascular extracellular matrix in an oral lesion biopsy from an affected family member. CONCLUSIONS Factor V east Texas bleeding disorder was diagnosed in an extended family. The variant was autosomal dominant and highly penetrant. Elevated plasma TFPIα, rather than platelet TFPIα, was likely the primary cause of bleeding. Plasma FV-short did not deplete TFPIα from extracellular matrix. In vitro thrombin generation was restored with an anti-TFPI antibody or factor VIIa suggesting effective therapies may be available. Increased awareness of, and testing for, bleeding disorders associated with F5 exon 13 variants and elevated plasma TFPI are needed.
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Affiliation(s)
| | - Sweta Gupta
- Indiana Hemophilia & Thrombosis Center, Indianapolis, IN USA 46260
| | | | - Brandon Hardesty
- Indiana Hemophilia & Thrombosis Center, Indianapolis, IN USA 46260
| | | | - Alan E. Mast
- Versiti, Blood Research Institute, Milwaukee, WI 53226
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226
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Dahlbäck B, Tran S. The preAR2 region (1458-1492) in factor V-Short is crucial for the synergistic TFPIα-cofactor activity with protein S and the assembly of a trimolecular factor Xa-inhibitory complex comprising FV-Short, protein S, and TFPIα. J Thromb Haemost 2022; 20:58-68. [PMID: 34623729 DOI: 10.1111/jth.15547] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 10/05/2021] [Indexed: 01/22/2023]
Abstract
BACKGROUND Factor V-Short (FV756-1458) is a natural splice variant in which 702 residues are deleted from the B domain. It exposes an acid region (AR2; 1493-1537) that binds tissue factor pathway inhibitor alpha (TFPIα). Protein S also interacts with TFPIα and serves as TFPIα-cofactor in factor Xa (FXa) inhibition. FV-Short and protein S function as synergistic TFPIα-cofactors in inhibition of FXa. FV810-1492 is an artificial FV-Short variant that cannot synergize with protein S as TFPIα cofactor even though it contains AR2 and binds TFPIα. OBJECTIVE To elucidate the mechanisms for the synergism between FV756-1458 and protein S as TFPIα cofactors. METHODS Four FV-Short variants were created, FV756-1458 and FV712-1458 contained the preAR2 region (1458-1492), whereas FV810-1492 and FV713-1492 lacked this region. The synergistic TFPIα cofactor activity between FV-Short variants and protein S was analyzed by FXa-inhibition. A microtiter-based assay tested binding between FV-Short variants, protein S, and TFPIα. RESULTS The two preAR2-containing FV-Short variants were active as synergistic TFPIα cofactors, whereas the other two were inactive. All variants bound to TFPIα. None of the FV-Short variants bound directly to protein S. The combination of TFPIα and preAR2-containing FV-Short variants bound protein S, whereas TFPIα together with the preAR2-minus variants did not. Protein S potentiated TFPIα-binding to the preAR2-containing variants and binding between TFPIα and protein S was stimulated only by the preAR2-containing variants. CONCLUSION The preAR2 region is demonstrated to be crucial for the synergistic TFPIα-cofactor activity between FV-Short and protein S and for the assembly of a trimolecular FXa-inhibitory complex comprising FV-Short, protein S, and TFPIα.
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Affiliation(s)
- Björn Dahlbäck
- Department of Translational Medicine, Lund University, University Hospital, Malmö, Sweden
| | - Sinh Tran
- Department of Translational Medicine, Lund University, University Hospital, Malmö, Sweden
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15
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Antisense-Mediated Down-Regulation of Factor V-Short Splicing in a Liver Cell Line Model. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11209621] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Coagulation factor V (FV) is a liver-derived protein encoded by the F5 gene. Alternative splicing of F5 exon 13 produces a low-abundance splicing isoform, known as FV-short, which binds the anticoagulant protein tissue factor pathway inhibitor (TFPIα) with high affinity, stabilising it in the circulation and potently enhancing its anticoagulant activity. Accordingly, rare F5 gene mutations that up-regulate FV-short splicing are associated with bleeding. In this study we have explored the possibility of decreasing FV-short splicing by antisense-based splicing modulation. To this end, we have designed morpholino antisense oligonucleotides (MAOs) targeting the FV-short-specific donor and acceptor splice sites and tested their efficacy in a liver cell line (HepG2) that naturally expresses full-length FV and FV-short. Cells were treated with 0–20 µM MAO, and full-length FV and FV-short mRNA expression was analysed by RT-(q)PCR. Both MAOs, alone or in combination, decreased the FV-short/full-length FV mRNA ratio down to ~50% of its original value in a specific and dose-dependent manner. This pilot study provides proof-of-principle for the possibility to decrease FV-short expression by antisense-mediated splicing modulation. In turn, this may form the basis for novel therapeutic approaches to bleeding disorders caused by FV-short over-expression and/or elevated TFPIα (activity) levels.
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Castoldi E. F5-Atlanta: Factor V-short strikes again. J Thromb Haemost 2021; 19:1638-1640. [PMID: 34176223 PMCID: PMC8362210 DOI: 10.1111/jth.15351] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 04/20/2021] [Accepted: 04/20/2021] [Indexed: 11/30/2022]
Affiliation(s)
- Elisabetta Castoldi
- Department of BiochemistryCARIMMaastricht UniversityMaastrichtthe Netherlands
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