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Hopp MT, Ugurlar D, Pezeshkpoor B, Biswas A, Ramoji A, Neugebauer U, Oldenburg J, Imhof D. In-depth structure-function profiling of the complex formation between clotting factor VIII and heme. Thromb Res 2024; 237:184-195. [PMID: 38631156 DOI: 10.1016/j.thromres.2024.04.006] [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: 01/10/2024] [Revised: 04/04/2024] [Accepted: 04/10/2024] [Indexed: 04/19/2024]
Abstract
BACKGROUND AND AIMS Blood disorders, such as sickle cell disease, and other clinical conditions are often accompanied by intravascular hemolytic events along with the development of severe coagulopathies. Hemolysis, in turn, leads to the accumulation of Fe(II/III)-protoporphyrin IX (heme) in the intravascular compartment, which can trigger a variety of proinflammatory and prothrombotic reactions. As such, heme binding to the blood coagulation proteins factor VIII (FVIII), fibrinogen, and activated protein C with functional consequences has been demonstrated earlier. METHODS We herein present an in-depth characterization of the FVIII-heme interaction at the molecular level and its (patho-)physiological relevance through the application of biochemical, biophysical, structural biology, bioinformatic, and diagnostic tools. RESULTS FVIII has a great heme-binding capacity with seven heme molecules associating with the protein. The respective binding sites were identified by investigating heme binding to FVIII-derived peptides in combination with molecular docking and dynamic simulation studies of the complex as well as cryo-electron microscopy, revealing three high-affinity and four moderate heme-binding motifs (HBMs). Furthermore, the relevance of the FVIII-heme complex formation was characterized in physiologically relevant assay systems, revealing a ~ 50 % inhibition of the FVIII cofactor activity even in the protein-rich environment of blood plasma. CONCLUSION Our study provides not only novel molecular insights into the FVIII-heme interaction and its physiological relevance, but also strongly suggests the reduction of the intrinsic pathway and the accentuation of the final clotting step (by, for example, fibrinogen crosslinking) in hemolytic conditions as well as a future perspective in the context of FVIII substitution therapy of hemorrhagic events in hemophilia A patients.
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Affiliation(s)
- Marie-T Hopp
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, Bonn, Germany; Department of Chemistry, Institute for Integrated Natural Sciences, University of Koblenz, Koblenz, Germany.
| | - Deniz Ugurlar
- Center for Electron Microscopy, Thermo Fisher Scientific, Eindhoven, the Netherlands
| | - Behnaz Pezeshkpoor
- Institute of Experimental Hematology and Transfusion Medicine, University Hospital Bonn, Bonn, Germany
| | - Arijit Biswas
- Institute of Experimental Hematology and Transfusion Medicine, University Hospital Bonn, Bonn, Germany
| | - Anuradha Ramoji
- Leibniz Institute of Photonic Technology, Jena, Germany; Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Jena, Germany
| | - Ute Neugebauer
- Leibniz Institute of Photonic Technology, Jena, Germany; Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Jena, Germany; Center for Sepsis Control and Care, Jena University Hospital, Jena, Germany
| | - Johannes Oldenburg
- Institute of Experimental Hematology and Transfusion Medicine, University Hospital Bonn, Bonn, Germany
| | - Diana Imhof
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, Bonn, Germany.
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Takeyama M, Furukawa S, Sasai K, Horiuchi K, Nogami K. Factor VIII A3 domain residues 1793-1795 represent a factor IXa-interactive site in the tenase complex. Biochim Biophys Acta Gen Subj 2023; 1867:130381. [PMID: 37207906 DOI: 10.1016/j.bbagen.2023.130381] [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: 11/15/2022] [Revised: 05/09/2023] [Accepted: 05/15/2023] [Indexed: 05/21/2023]
Abstract
BACKGROUND Factor (F)VIII functions as a cofactor in the tenase complex responsible for conversion of FX to FXa by FIXa. Earlier studies indicated that one of the FIXa-binding sites is located in residues 1811-1818 (crucially F1816) of the FVIII A3 domain. A putative, three-dimensional structure model of the FVIIIa molecule suggested that residues 1790-1798 form a V-shaped loop, and juxtapose residues 1811-1818 on the extended surface of FVIIIa. AIM To examine FIXa molecular interactions in the clustered acidic sites of FVIII including residues 1790-1798. METHODS AND RESULTS Specific ELISA's demonstrated that the synthetic peptides, encompassing residues 1790-1798 and 1811-1818, competitively inhibited the binding of FVIII light chain to active-site-blocked Glu-Gly-Arg-FIXa (EGR-FIXa) (IC50; 19.2 and 42.9 μM, respectively), in keeping with a possible role for the 1790-1798 in FIXa interactions. Surface plasmon resonance-based analyses demonstrated that variants of FVIII, in which the clustered acidic residues (E1793/E1794/D1793) or F1816 contained substituted alanine, bound to immobilized biotin labeled-Phe-Pro-Arg-FIXa (bFPR-FIXa) with a 1.5-2.2-fold greater KD compared to wild-type FVIII (WT). Similarly, FXa generation assays indicated that E1793A/E1794A/D1795A and F1816A mutants increased the Km by 1.6-2.8-fold relative to WT. Furthermore, E1793A/E1794A/D1795A/F1816A mutant showed that the Km was increased by 3.4-fold and the Vmax was decreased by 0.75-fold, compared to WT. Molecular dynamics simulation analyses revealed the subtle changes between WT and E1793A/E1794A/D1795A mutant, supportive of the contribution of these residues for FIXa interaction. CONCLUSION The 1790-1798 region in the A3 domain, especially clustered acidic residues E1793/E1794/D1795, contains a FIXa-interactive site.
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Affiliation(s)
- Masahiro Takeyama
- Department of Pediatrics, Nara Medical University, Kashihara, Nara 634-8522, Japan.
| | - Shoko Furukawa
- Department of Pediatrics, Nara Medical University, Kashihara, Nara 634-8522, Japan
| | - Kana Sasai
- Department of Pediatrics, Nara Medical University, Kashihara, Nara 634-8522, Japan
| | - Kaoru Horiuchi
- Department of Pediatrics, Nara Medical University, Kashihara, Nara 634-8522, Japan
| | - Keiji Nogami
- Department of Pediatrics, Nara Medical University, Kashihara, Nara 634-8522, Japan
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3
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Sarafanov AG. Plasma Clearance of Coagulation Factor VIII and Extension of Its Half-Life for the Therapy of Hemophilia A: A Critical Review of the Current State of Research and Practice. Int J Mol Sci 2023; 24:ijms24108584. [PMID: 37239930 DOI: 10.3390/ijms24108584] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 05/05/2023] [Accepted: 05/08/2023] [Indexed: 05/28/2023] Open
Abstract
Factor VIII (FVIII) is an important component of blood coagulation as its congenital deficiency results in life-threatening bleeding. Current prophylactic therapy of the disease (hemophilia A) is based on 3-4 intravenous infusions of therapeutic FVIII per week. This poses a burden on patients, demanding reduction of infusion frequency by using FVIII with extended plasma half-life (EHL). Development of these products requires understanding FVIII plasma clearance mechanisms. This paper overviews (i) an up-to-date state of the research in this field and (ii) current EHL FVIII products, including recently approved efanesoctocog alfa, for which the plasma half-life exceeds a biochemical barrier posed by von Willebrand factor, complexed with FVIII in plasma, which results in ~1 per week infusion frequency. We focus on the EHL FVIII products' structure and function, in particular related to the known discrepancy in results of one-stage clotting (OC) and chromogenic substrate (CS) assays used to assign the products' potency, dosing, and for clinical monitoring in plasma. We suggest a possible root cause of these assays' discrepancy that is also pertinent to EHL factor IX variants used to treat hemophilia B. Finally, we discuss approaches in designing future EHL FVIII variants, including those to be used for hemophilia A gene therapy.
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Affiliation(s)
- Andrey G Sarafanov
- Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD 20993, USA
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4
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Childers KC, Peters SC, Lollar P, Spencer HT, Doering CB, Spiegel PC. SAXS analysis of the intrinsic tenase complex bound to a lipid nanodisc highlights intermolecular contacts between factors VIIIa/IXa. Blood Adv 2022; 6:3240-3254. [PMID: 35255502 PMCID: PMC9198903 DOI: 10.1182/bloodadvances.2021005874] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 02/27/2022] [Indexed: 11/20/2022] Open
Abstract
The intrinsic tenase (Xase) complex, formed by factors (f) VIIIa and fIXa, forms on activated platelet surfaces and catalyzes the activation of factor X to Xa, stimulating thrombin production in the blood coagulation cascade. The structural organization of the membrane-bound Xase complex remains largely unknown, hindering our understanding of the structural underpinnings that guide Xase complex assembly. Here, we aimed to characterize the Xase complex bound to a lipid nanodisc with biolayer interferometry (BLI), Michaelis-Menten kinetics, and small-angle X-ray scattering (SAXS). Using immobilized lipid nanodiscs, we measured binding rates and nanomolar affinities for fVIIIa, fIXa, and the Xase complex. Enzyme kinetic measurements demonstrated the assembly of an active enzyme complex in the presence of lipid nanodiscs. An ab initio molecular envelope of the nanodisc-bound Xase complex allowed us to computationally model fVIIIa and fIXa docked onto a flexible lipid membrane and identify protein-protein interactions. Our results highlight multiple points of contact between fVIIIa and fIXa, including a novel interaction with fIXa at the fVIIIa A1-A3 domain interface. Lastly, we identified hemophilia A/B-related mutations with varying severities at the fVIIIa/fIXa interface that may regulate Xase complex assembly. Together, our results support the use of SAXS as an emergent tool to investigate the membrane-bound Xase complex and illustrate how mutations at the fVIIIa/fIXa dimer interface may disrupt or stabilize the activated enzyme complex.
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Affiliation(s)
- Kenneth C Childers
- Department of Chemistry, Western Washington University, Bellingham, WA; and
| | - Shaun C Peters
- Department of Chemistry, Western Washington University, Bellingham, WA; and
| | - Pete Lollar
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Emory University, Atlanta, GA
| | - Harold Trent Spencer
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Emory University, Atlanta, GA
| | - Christopher B Doering
- Department of Pediatrics, Aflac Cancer and Blood Disorders Center, Children's Healthcare of Atlanta, Emory University, Atlanta, GA
| | - Paul C Spiegel
- Department of Chemistry, Western Washington University, Bellingham, WA; and
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5
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Lopes TJS, Rios R, Nogueira T, Mello RF. Protein residue network analysis reveals fundamental properties of the human coagulation factor VIII. Sci Rep 2021; 11:12625. [PMID: 34135429 PMCID: PMC8209229 DOI: 10.1038/s41598-021-92201-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 06/08/2021] [Indexed: 11/09/2022] Open
Abstract
Hemophilia A is an X-linked inherited blood coagulation disorder caused by the production and circulation of defective coagulation factor VIII protein. People living with this condition receive either prophylaxis or on-demand treatment, and approximately 30% of patients develop inhibitor antibodies, a serious complication that limits treatment options. Although previous studies performed targeted mutations to identify important residues of FVIII, a detailed understanding of the role of each amino acid and their neighboring residues is still lacking. Here, we addressed this issue by creating a residue interaction network (RIN) where the nodes are the FVIII residues, and two nodes are connected if their corresponding residues are in close proximity in the FVIII protein structure. We studied the characteristics of all residues in this network and found important properties related to disease severity, interaction to other proteins and structural stability. Importantly, we found that the RIN-derived properties were in close agreement with in vitro and clinical reports, corroborating the observation that the patterns derived from this detailed map of the FVIII protein architecture accurately capture the biological properties of FVIII.
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Affiliation(s)
- Tiago J S Lopes
- Department of Reproductive Biology, Center for Regenerative Medicine, National Center for Child Health and Development Research Institute, 2-10-1 Okura, Setagaya-ku, Tokyo, 157-8535, Japan.
| | - Ricardo Rios
- Department of Computer Science, Federal University of Bahia, Salvador, Brazil.,Institute of Mathematics and Computer Science, University of São Paulo, São Paulo, Brazil
| | - Tatiane Nogueira
- Department of Computer Science, Federal University of Bahia, Salvador, Brazil.,Institute of Mathematics and Computer Science, University of São Paulo, São Paulo, Brazil
| | - Rodrigo F Mello
- Institute of Mathematics and Computer Science, University of São Paulo, São Paulo, Brazil.,Itaú Unibanco, Av. Eng. Armando de Arruda Pereira, 707, Jabaquara, São Paulo, 04309-010, Brazil
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6
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Abstract
The formation of membrane-bound complexes between specific coagulation factors at different cell surfaces is required for effective blood clotting. The most important of these complexes, the intrinsic Tenase and Prothrombinase complexes, are formed on the activated platelet surface during the propagation phase of coagulation. These two complexes are highly specific in their assembly mechanism and function modulated by anionic membranes, thus offering desirable targets for pharmaceutical interventions. Factor V (FV) and factor VIII (FVIII) are highly homologous non-enzymatic proteins. In their active state, FVa and FVIIIa serve as cofactors for the respective serine proteases factor Xa (FXa) and factor IXa (FIXa), significantly increasing their catalytic activity. This is achieved by forming well organized membrane-bound complexes at the phosphatidylserine rich activated platelet membrane in the presence of Ca2+ ions. The tenase (FVIIIa/FIXa) complex, catalyzes the proteolytic conversion of FX to FXa. Subsequently the prothrombinase (FVa/FXa) complex catalyzes the conversion of prothrombin to thrombin, required for efficient blood clotting. Although significant knowledge of FV and FVIII biochemistry and regulation has been achieved, the molecular mechanisms of their function are yet to be defined. Understanding the geometric assembly of the tenase and prothrombinase complexes is paramount in defining the structural basis of bleeding and thrombotic disorders. Such knowledge will enable the design of efficient pro- and anticoagulant therapies critical for regulating abnormal hemostasis. In this chapter, we will summarize the findings to date, showing our achievement in the field and outlining the future findings required to grasp the complexity of these proteins.
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Affiliation(s)
- Svetla Stoilova-McPhie
- Center for Nanoscale Systems (CNS), Laboratory For Integrated Sciences and Engineering (LISE), Faculty of Art and Sciences (FAS), Harvard University, 11 Oxford Street, Cambridge, MA, 02138, England, UK.
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7
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Abstract
Von Willebrand factor (VWF) and coagulation factor VIII (FVIII) circulate as a complex in plasma and have a major role in the hemostatic system. VWF has a dual role in hemostasis. It promotes platelet adhesion by anchoring the platelets to the subendothelial matrix of damaged vessels and it protects FVIII from proteolytic degradation. Moreover, VWF is an acute phase protein that has multiple roles in vascular inflammation and is massively secreted from Weibel-Palade bodies upon endothelial cell activation. Activated FVIII on the other hand, together with coagulation factor IX forms the tenase complex, an essential feature of the propagation phase of coagulation on the surface of activated platelets. VWF deficiency, either quantitative or qualitative, results in von Willebrand disease (VWD), the most common bleeding disorder. The deficiency of FVIII is responsible for Hemophilia A, an X-linked bleeding disorder. Here, we provide an overview on the role of the VWF-FVIII interaction in vascular physiology.
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Affiliation(s)
- Klytaimnistra Kiouptsi
- Center for Thrombosis and Hemostasis (CTH), University Medical Center Mainz, Langenbeckstrasse 1, Building 708, 55131, Mainz, Germany
| | - Christoph Reinhardt
- Center for Thrombosis and Hemostasis (CTH), University Medical Center Mainz, Langenbeckstrasse 1, Building 708, 55131, Mainz, Germany.
- German Center for Cardiovascular Research (DZHK), Partner Site RheinMain, Mainz, Germany.
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8
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Soeda T, Ogiwara K, Shima M, Nogami K. Interactions between residues 2228–2240 within factor VIIIa C2 domain and factor IXa Gla domain contribute to propagation of clot formation. Thromb Haemost 2017; 106:893-900. [DOI: 10.1160/th11-03-0203] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Accepted: 08/01/2011] [Indexed: 11/05/2022]
Abstract
SummaryFactor (F)VIII functions as a cofactor in the tenase complex responsible for phospholipid (PL)-dependent FXa generation by FIXa. We have recently reported that the FVIIIa C2 domain (residues 2228–2240) interacts with the FIXa Gla domain in this complex. We examined the role of this interaction in the generation of tenase activity during the process of clot formation, using a synthetic peptide corresponding to residues 2228–2240. The peptide 2228–2240 inhibited FVIIIa/FIXa-mediated FX activation dose-dependently in the presence of PL by >95% (IC50; ~10 μM). This effect was significantly greater than that obtained by peptide 1804–1818 (IC50; ~180 μM) which corresponds to another FIXa-interactive site in the light chain that provides the majority of binding energy for FIXa interaction. Peptide 2228–2240 had little effect on the prothrombin time and did not inhibit FIX activation in the coagulation process mediated by FVIIa/tissue factor or FXIa, suggesting specific inhibition of the intrinsic tenase complex. Clot waveform analysis, a plasma based-assay used to evaluate the process of intrinsic coagulation, demonstrated that peptide 2228–2240 significantly depressed both maximum coagulation velocity (|min1|) and acceleration (|min2|), reflecting the propagation of clot formation, although the clotting time was only marginally prolonged. Thromboelastography, an alternative whole blood based-assay, demonstrated that the peptide inhibited clot formation time, α-angle and maximal clot firmness, but had little effect on the clotting time. Interactions of the FVIIIa C2 domain (residues 2228–2240) with the FIXa Gla domain in the tenase complex appeared to contribute essentially to the propagation of clot formation.
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9
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Ogiwara K, Matsumoto T, Nishiya K, Takeyama M, Shima M, Nogami K. Mechanisms of human neutrophil elastase-catalysed inactivation of factor VIII(a). Thromb Haemost 2017; 105:968-80. [DOI: 10.1160/th10-12-0777] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Accepted: 03/06/2011] [Indexed: 11/05/2022]
Abstract
SummaryMechanisms of inflammation and coagulation are linked through various pathways. Human neutrophil elastase (HNE), can bind to activated platelets, might be localised on platelet membranes that provide negatively-charged phospholipid essential for the optimum function of tenase complex. In this study, we examined the effect of HNE on factor (F)VIII. FVIII activity was rapidly diminished in the presence of HNE and was undetectable within 10 minutes. The inactivation rate waŝ8-fold greater than that of activated protein C (APC). This time-dependent inactivation was moderately affected by von Willebrand factor. HNE proteolysed the heavy chain (HCh) of FVIII into two terminal products, A11–358 and A2375–708, by limited proteolysis at Val358, Val374, and Val708. Cleavage at Val708 was much slower than that at Val358 in the >90-kDa A1-A2-B compared to the 90-kDa A1-A2. The 80-kDa light chain (LCh) was proteolysed to 75-kDa product by cleavage at Val1670. HNE-cata- lysed FVIIIa inactivation was markedly slower than that of native FVIII (by ~25-fold), due to delayed cleavage at Val708 in FVIIIa. The inactivation rate mediated by HNE was ~8-fold lower than that by APC. Cleavages at Val358 and Val708 were regulated by the presence of LCh and HCh, respectively. In conclusion, HNE-catalysed FVIII inactivation was associated with the limited-proteolysis that led to A11–358, A2375–708, and A3-C1-C21671–2332, and subsequently to critical cleavage at Val708. HNE-related FVIII(a) reaction might play a role in inactivation of HNE-induced coagulation process, and appeared to depend on the amounts of inactivated FVIII and active FVIIIa which is predominantly resistant to HNE inactivation.Note: An account of this work was presented at the 51st annual meeting of the American Society of Hematology, December 10, 2009, New Orleans, LA, USA.
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10
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Hartholt RB, Wroblewska A, Herczenik E, Peyron I, Ten Brinke A, Rispens T, Nolte MA, Slot E, Claassens JW, Nimmerjahn F, Verbeek JS, Voorberg J. Enhanced uptake of blood coagulation factor VIII containing immune complexes by antigen presenting cells. J Thromb Haemost 2017; 15:329-340. [PMID: 27868337 DOI: 10.1111/jth.13570] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Indexed: 02/01/2023]
Abstract
Essentials Anti-factor (F) VIII antibody formation is a major complication in the treatment of hemophilia A. We investigated uptake of FVIII and FVIII immune complex by bone marrow derived dendritic cells. Immune complex formation increased uptake of FVIII 3-4 fold in a Fcγ receptor dependent manner. FVIII immune complex binding to Fcγ receptors may modulate immune tolerance induction. SUMMARY Background A major complication in the treatment of hemophilia A is the development of inhibitory antibodies targeting coagulation factor VIII (FVIII). Eradication of these inhibitors can be established by immune tolerance induction (ITI), which consists of daily administration of high dosages of FVIII. FVIII immune complexes (FVIII-IC) could be formed following FVIII infusion in patients with pre-existing anti-FVIII antibodies. Objectives Here we studied endocytosis of FVIII-IC by bone marrow-derived dendritic cells (BMDCs). Methods BMDCs were pulsed with FVIII/FVIII-IC and uptake was assessed by flow cytometry and confocal imaging. Results BMDCs were able to efficiently internalize FVIII-IC in a dose-dependent manner, 3-4-fold more efficiently when compared with equimolar concentrations of non-complexed FVIII. Uptake of FVIII-IC, but not FVIII alone, could be inhibited with anti-Fcγ receptor (FcγR) antibody 2.4G2, indicating functional involvement of FcγR. No internalization of FVIII-IC was observed in BMDCs lacking FcγRI, FcγRIIb, FcγRIII and FcγRIV. Genetic ablation of FcγRIIb, FcγRIII or FcγRIV individually did not affect the ability of anti-FVIII IgG to promote the uptake of FVIII. BMDCs lacking FcγRI showed lower FVIII-IC uptake levels when compared with other single FcγR null BMDCs. Expression of the inhibitory FcγRIIb alone was sufficient to internalize FVIII-IC more efficiently than FVIII. Conclusions FcγR are critical in the internalization of FVIII-IC by BMDCs and multiple FcγR can contribute independently to this process. Our findings provide a basis for future studies to address whether the outcome of ITI is dependent on the interplay between FVIII-IC and inhibitory and activating FcγR.
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Affiliation(s)
- R B Hartholt
- Department of Plasma Proteins, Sanquin-AMC Landsteiner Laboratory, Amsterdam, the Netherlands
| | - A Wroblewska
- Department of Plasma Proteins, Sanquin-AMC Landsteiner Laboratory, Amsterdam, the Netherlands
| | - E Herczenik
- Department of Plasma Proteins, Sanquin-AMC Landsteiner Laboratory, Amsterdam, the Netherlands
| | - I Peyron
- Department of Plasma Proteins, Sanquin-AMC Landsteiner Laboratory, Amsterdam, the Netherlands
| | - A Ten Brinke
- Department of Immunopathology, Sanquin-AMC Landsteiner Laboratory, Amsterdam, the Netherlands
| | - T Rispens
- Department of Immunopathology, Sanquin-AMC Landsteiner Laboratory, Amsterdam, the Netherlands
| | - M A Nolte
- Department of Hematopoiesis, Sanquin-AMC Landsteiner Laboratory, Amsterdam, the Netherlands
| | - E Slot
- Department of Hematopoiesis, Sanquin-AMC Landsteiner Laboratory, Amsterdam, the Netherlands
| | - J W Claassens
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | - F Nimmerjahn
- Chair of Genetics, Department of Biology, University of Erlangen-Nuremberg, Erlangen, Germany
| | - J S Verbeek
- Department of Human Genetics, Leiden University Medical Center, Leiden, the Netherlands
| | - J Voorberg
- Department of Plasma Proteins, Sanquin-AMC Landsteiner Laboratory, Amsterdam, the Netherlands
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11
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Chen J, Wang J, Lin XY, Xu YW, He ZH, Li HY, Chen SQ, Jiang WY. Genetic diagnosis in Hemophilia A from southern China: five novel mutations and one preimplantation genetic analysis. Int J Lab Hematol 2016; 39:191-201. [DOI: 10.1111/ijlh.12602] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 10/03/2016] [Indexed: 12/23/2022]
Affiliation(s)
- J. Chen
- Department of Medical Genetics; Zhongshan School of Medicine; Sun Yat-Sen University; GuangZhou China
| | - J. Wang
- The First Affiliated Hospital; Sun Yat-sen University; GuangZhou China
| | - X. Y. Lin
- Department of Medical Genetics; Zhongshan School of Medicine; Sun Yat-Sen University; GuangZhou China
| | - Y. W. Xu
- The First Affiliated Hospital; Sun Yat-sen University; GuangZhou China
| | - Z. H. He
- Department of Medical Genetics; Zhongshan School of Medicine; Sun Yat-Sen University; GuangZhou China
| | - H. Y. Li
- Department of Medical Genetics; Zhongshan School of Medicine; Sun Yat-Sen University; GuangZhou China
| | - S. Q. Chen
- Department of Medical Genetics; Zhongshan School of Medicine; Sun Yat-Sen University; GuangZhou China
| | - W. Y. Jiang
- Department of Medical Genetics; Zhongshan School of Medicine; Sun Yat-Sen University; GuangZhou China
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12
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Dalm D, Galaz-Montoya JG, Miller JL, Grushin K, Villalobos A, Koyfman AY, Schmid MF, Stoilova-McPhie S. Dimeric Organization of Blood Coagulation Factor VIII bound to Lipid Nanotubes. Sci Rep 2015; 5:11212. [PMID: 26082135 PMCID: PMC4469981 DOI: 10.1038/srep11212] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 05/05/2015] [Indexed: 11/09/2022] Open
Abstract
Membrane-bound Factor VIII (FVIII) has a critical function in blood coagulation as the pro-cofactor to the serine-protease Factor IXa (FIXa) in the FVIIIa-FIXa complex assembled on the activated platelet membrane. Defects or deficiency of FVIII cause Hemophilia A, a mild to severe bleeding disorder. Despite existing crystal structures for FVIII, its membrane-bound organization has not been resolved. Here we present the dimeric FVIII membrane-bound structure when bound to lipid nanotubes, as determined by cryo-electron microscopy. By combining the structural information obtained from helical reconstruction and single particle subtomogram averaging at intermediate resolution (15-20 Å), we show unambiguously that FVIII forms dimers on lipid nanotubes. We also demonstrate that the organization of the FVIII membrane-bound domains is consistently different from the crystal structure in solution. The presented results are a critical step towards understanding the mechanism of the FVIIIa-FIXa complex assembly on the activated platelet surface in the propagation phase of blood coagulation.
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Affiliation(s)
- Daniela Dalm
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Jesus G Galaz-Montoya
- 1] Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA [2] National Center for Macromolecular Imaging, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jaimy L Miller
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Kirill Grushin
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Alex Villalobos
- School of Medicine, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Alexey Y Koyfman
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Michael F Schmid
- 1] Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA [2] National Center for Macromolecular Imaging, Baylor College of Medicine, Houston, TX 77030, USA
| | - Svetla Stoilova-McPhie
- 1] Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX 77555, USA [2] Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX 77555, USA
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Omental implantation of BOECs in hemophilia dogs results in circulating FVIII antigen and a complex immune response. Blood 2014; 123:4045-53. [PMID: 24829206 DOI: 10.1182/blood-2013-12-545780] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Ex vivo gene therapy strategies avoid systemic delivery of viruses thereby mitigating the risk of vector-associated immunogenicity. Previously, we delivered autologous factor VIII (FVIII)-expressing blood outgrowth endothelial cells (BOECs) to hemophilia A mice and showed that these cells remained sequestered within the implanted matrix and provided therapeutic levels of FVIII. Prior to translating this strategy into the canine (c) model of hemophilia A, we increased cFVIII transgene expression by at least 100-fold with the use of the elongation factor 1 alpha (EF1α) promoter and a strong endothelial enhancer element. BOECs isolated from hemophilia A dogs transduced with this lentiviral vector express levels of cFVIII ranging between 1.0 and 1.5 U/mL per 10(6) cells over 24 hours. Autologous BOECs have been implanted into the omentum of 2 normal and 3 hemophilia A dogs. These implanted cells formed new vessels in the omentum. All 3 hemophilia A dogs treated with FVIII-expressing autologous BOECs developed anti-FVIII immunoglobulin G2 antibodies, but in only 2 of the dogs were these antibodies inhibitory. FVIII antigen levels >40% in the absence of FVIII coagulant function were detected in the circulation for up to a year after a single gene therapy treatment, indicating prolonged cellular viability and synthesis of FVIII.
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Zimmermann MA, Oldenburg J, Müller CR, Rost S. Expression studies of mutant factor VIII alleles with premature termination codons with regard to inhibitor formation. Haemophilia 2014; 20:e215-21. [DOI: 10.1111/hae.12388] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/27/2014] [Indexed: 01/21/2023]
Affiliation(s)
- M. A. Zimmermann
- Department of Human Genetics; University of Würzburg; Würzburg Germany
| | - J. Oldenburg
- Institute of Experimental Haematology and Transfusion Medicine; University of Bonn; Bonn Germany
| | - C. R. Müller
- Department of Human Genetics; University of Würzburg; Würzburg Germany
| | - S. Rost
- Department of Human Genetics; University of Würzburg; Würzburg Germany
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15
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Bloem E, Meems H, van den Biggelaar M, Mertens K, Meijer AB. A3 domain region 1803-1818 contributes to the stability of activated factor VIII and includes a binding site for activated factor IX. J Biol Chem 2013; 288:26105-26111. [PMID: 23884417 DOI: 10.1074/jbc.m113.500884] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A recent chemical footprinting study in our laboratory suggested that region 1803-1818 might contribute to A2 domain retention in activated factor VIII (FVIIIa). This site has also been implicated to interact with activated factor IX (FIXa). Asn-1810 further comprises an N-linked glycan, which seems incompatible with a role of the amino acids 1803-1818 for FIXa or A2 domain binding. In the present study, FVIIIa stability and FIXa binding were evaluated in a FVIII-N1810C variant, and two FVIII variants in which residues 1803-1810 and 1811-1818 are replaced by the corresponding residues of factor V (FV). Enzyme kinetic studies showed that only FVIII/FV 1811-1818 has a decreased apparent binding affinity for FIXa. Flow cytometry analysis indicated that fluorescent FIXa exhibits impaired complex formation with only FVIII/FV 1811-1818 on lipospheres. Site-directed mutagenesis revealed that Phe-1816 contributes to the interaction with FIXa. To evaluate FVIIIa stability, the FVIII/FV chimeras were activated by thrombin, and the decline in cofactor function was followed over time. FVIII/FV 1803-1810 and FVIII/FV 1811-1818 but not FVIII-N1810C showed a decreased FVIIIa half-life. However, when the FVIII variants were activated in presence of FIXa, only FVIII/FV 1811-1818 demonstrated an enhanced decline in cofactor function. Surface plasmon resonance analysis revealed that the FVIII variants K1813A/K1818A, E1811A, and F1816A exhibit enhanced dissociation after activation. The results together demonstrate that the glycan at 1810 is not involved in FVIII cofactor function, and that Phe-1816 of region 1811-1818 contributes to FIXa binding. Both regions 1803-1810 and 1811-1818 contribute to FVIIIa stability.
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Affiliation(s)
- Esther Bloem
- From the Department of Plasma Proteins, Sanquin Research, 1066 CX Amsterdam, The Netherlands and
| | - Henriet Meems
- From the Department of Plasma Proteins, Sanquin Research, 1066 CX Amsterdam, The Netherlands and
| | | | - Koen Mertens
- From the Department of Plasma Proteins, Sanquin Research, 1066 CX Amsterdam, The Netherlands and; Pharmaceutical Sciences, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 1066 CX Amsterdam, The Netherlands
| | - Alexander B Meijer
- From the Department of Plasma Proteins, Sanquin Research, 1066 CX Amsterdam, The Netherlands and; Pharmaceutical Sciences, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 1066 CX Amsterdam, The Netherlands.
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16
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Rosset C, Vieira IA, Sinigaglia M, Gorziza RP, Salzano FM, Bandinelli E. Detection of new mutations and molecular pathology of mild and moderate haemophilia A patients from southern Brazil. Haemophilia 2013; 19:773-81. [DOI: 10.1111/hae.12172] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/08/2013] [Indexed: 01/17/2023]
Affiliation(s)
- C. Rosset
- Genetics Department; Biosciences Institute; Federal University of Rio Grande do Sul; Porto Alegre; RS; Brazil
| | - I. A. Vieira
- Genetics Department; Biosciences Institute; Federal University of Rio Grande do Sul; Porto Alegre; RS; Brazil
| | - M. Sinigaglia
- Genetics Department; Biosciences Institute; Federal University of Rio Grande do Sul; Porto Alegre; RS; Brazil
| | - R. P. Gorziza
- Genetics Department; Biosciences Institute; Federal University of Rio Grande do Sul; Porto Alegre; RS; Brazil
| | - F. M. Salzano
- Genetics Department; Biosciences Institute; Federal University of Rio Grande do Sul; Porto Alegre; RS; Brazil
| | - E. Bandinelli
- Genetics Department; Biosciences Institute; Federal University of Rio Grande do Sul; Porto Alegre; RS; Brazil
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18
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Repessé Y, Dimitrov JD, Peyron I, Farrokhi Moshai E, Kiger L, Dasgupta S, Delignat S, Marden MC, Kaveri SV, Lacroix-Desmazes S. Heme binds to factor VIII and inhibits its interaction with activated factor IX. J Thromb Haemost 2012; 10:1062-71. [PMID: 22471307 DOI: 10.1111/j.1538-7836.2012.04724.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Heme is a redox active macrocyclic compound that is released upon tissue damage or hemorrhages. The extracellular release of large amounts of heme saturates scavenging heme-binding proteins. Free heme has been proposed to affect coagulation and has been co-purified with the factor VIII (FVIII)-von Willebrand factor (VWF) complex. The sites from which heme is released upon injury overlap with the sites to which FVIII is targeted for performing its hemostatic functions. OBJECTIVES To investigate the interaction of heme with FVIII and the consequence for the procoagulant activity of FVIII in vitro. METHODS AND RESULTS Heme bound to several sites on FVIII with high apparent affinity. Heme-binding inhibited FVIII procoagulant activity in a dose-dependent manner. FVIII inactivation in the presence of saturating amounts of heme implicated a reduced interaction of FVIII with activated FIX, as shown by ELISA, surface plasmon resonance and fluorescence quenching. Heme-mediated inactivation of FVIII was prevented by VWF, but not by human serum albumin, a heme-binding protein known for its protective activity in hemolytic conditions. CONCLUSIONS Our data identify FVIII as a novel heme-binding protein. Occupation of high affinity heme-binding sites on FVIII at low concentrations of free heme did not inactivate FVIII. Conversely, large molar excesses of heme over FVIII, which correspond to conditions of extensive heme release, inhibited FVIII activity in vitro. It remains to be demonstrated whether, under such conditions, heme-mediated modulation of the activity of FVIII plays some role in the regulation of coagulation.
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Takeyama M, Wakabayashi H, Fay PJ. Factor VIII light chain contains a binding site for factor X that contributes to the catalytic efficiency of factor Xase. Biochemistry 2012; 51:820-8. [PMID: 22224589 DOI: 10.1021/bi201731p] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Factor (F) VIII functions as a cofactor in FXase, markedly accelerating the rate of FIXa-catalyzed activation of FX. Earlier work identified a FX-binding site having μM affinity within the COOH-terminal region of the FVIIIa A1 subunit. In the present study, surface plasmon resonance (SPR), ELISA-based binding assays, and chemical cross-linking were employed to assess an interaction between FX and the FVIII light chain (A3C1C2 domains). SPR and ELISA-based assays showed that FVIII LC bound to immobilized FX (K(d) = 165 and 370 nM, respectively). Furthermore, active site-modified activated protein C (DEGR-APC) effectively competed with FX in binding FVIII LC (apparent K(i) = 82.7 nM). Western blotting revealed that the APC-catalyzed cleavage rate at Arg(336) was inhibited by FX in a concentration-dependent manner. A synthetic peptide comprising FVIII residues 2007-2016 representing a portion of an APC-binding site blocked the interaction of FX and FVIII LC (apparent K(i) = 152 μM) and directly bound to FX (K(d) = 7.7 μM) as judged by SPR and chemical cross-linking. Ala-scanning mutagenesis of this sequence revealed that the A3C1C2 subunit derived from FVIII variants Thr2012Ala and Phe2014Ala showed 1.5- and 1.8-fold increases in K(d) for FX, whereas this value using the A3C1C2 subunit from a Thr2012Ala/Leu2013Ala/Phe2014Ala triple mutant was increased >4-fold. FXase formed using this LC triple mutant demonstrated an ~4-fold increase in the K(m) for FX. These results identify a relatively high affinity and functional FX site within the FVIIIa A3C1C2 subunit and show a contribution of residues Thr2012 and Phe2014 to this interaction.
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Affiliation(s)
- Masahiro Takeyama
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, United States
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20
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Encapsulation of the peptide Ac–Glu–Thr–Lys–Thr–Tyr–Phe–Trp–Lys–NH2 into polyvinyl alcohol biodegradable formulations—Effect of calcium alginate. Carbohydr Polym 2012. [DOI: 10.1016/j.carbpol.2011.08.064] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Chavali S, Mahajan A, Ghosh S, Mondal B, Bharadwaj D. Protein molecular function influences mutation rates in human genetic diseases with allelic heterogeneity. Biochem Biophys Res Commun 2011; 412:716-22. [PMID: 21867677 DOI: 10.1016/j.bbrc.2011.08.038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Accepted: 08/07/2011] [Indexed: 11/20/2022]
Abstract
Molecular epidemiology studies have used the counts of different mutational types like transitions, transversions, etc. to identify putative mutagens, with little reference to gene organization and structure-function of the translated product. Moreover, geographical variation in the mutational spectrum is not limited to the mutational types at the nucleotide level but also have a bearing at the functional level. Here, we developed a novel measure to estimate the rate of spontaneous detrimental mutations called "mutation index" for comparing the mutational spectra consisting of all single base, missense, and non-missense changes. We have analyzed 1609 mutations occurring in 38 exons in 24 populations in three diseases viz. hemophilia B (F9 gene - 420 mutations in 9 populations across 8 exons), hemophilia A (F8 gene - 650, 8 and 26, respectively) and ovarian carcinoma (TP53 gene - 539, 7 and 4, respectively). We considered exons as units of evolution instead of the entire gene and observed feeble differences among populations implying lack of a mutagen-specific effect and the possibility of mutation causing endogenous factors. In all the three genes we observed elevated rates of detrimental mutations in exons encoding regions of significance for the molecular function of the protein. We propose that this can be extended to the entire exome with implications in exon-shuffling and complex human diseases.
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Affiliation(s)
- Sreenivas Chavali
- Genomics and Molecular Medicine Unit, Institute of Genomics and Integrative Biology, CSIR, Delhi, India.
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22
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Abstract
Factor VIII functions as a cofactor for Factor IXa in a membrane-bound enzyme complex. Membrane binding accelerates the activity of the Factor VIIIa-Factor IXa complex approx. 100000-fold, and the major phospholipid-binding motif of Factor VIII is thought to be on the C2 domain. In the present study, we prepared an fVIII-C2 (Factor VIII C2 domain) construct from Escherichia coli, and confirmed its structural integrity through binding of three distinct monoclonal antibodies. Solution-phase assays, performed with flow cytometry and FRET (fluorescence resonance energy transfer), revealed that fVIII-C2 membrane affinity was approx. 40-fold lower than intact Factor VIII. In contrast with the similarly structured C2 domain of lactadherin, fVIII-C2 membrane binding was inhibited by physiological NaCl. fVIII-C2 binding was also not specific for phosphatidylserine over other negatively charged phospholipids, whereas a Factor VIII construct lacking the C2 domain retained phosphatidyl-L-serine specificity. fVIII-C2 slightly enhanced the cleavage of Factor X by Factor IXa, but did not compete with Factor VIII for membrane-binding sites or inhibit the Factor Xase complex. Our results indicate that the C2 domain in isolation does not recapitulate the characteristic membrane binding of Factor VIII, emphasizing that its role is co-operative with other domains of the intact Factor VIII molecule.
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Structural basis of thrombin-mediated factor V activation: the Glu666-Glu672 sequence is critical for processing at the heavy chain-B domain junction. Blood 2011; 117:7164-73. [PMID: 21555742 DOI: 10.1182/blood-2010-10-315309] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Thrombin-catalyzed activation of coagulation factor V (FV) is an essential positive feedback reaction within the blood clotting system. Efficient processing at the N- (Arg(709)-Ser(710)) and C-terminal activation cleavage sites (Arg(1545)-Ser(1546)) requires initial substrate interactions with 2 clusters of positively charged residues on the proteinase surface, exosites I and II. We addressed the mechanism of activation of human factor V (FV) using peptides that cover the entire acidic regions preceding these cleavage sites, FV (657-709)/ (FVa2) and FV(1481-1545)/(FVa3). FVa2 appears to interact mostly with exosite I, while both exosites are involved in interactions with the C-terminal linker. The 1.7-Å crystal structure of irreversibly inhibited thrombin bound to FVa2 unambiguously reveals docking of FV residues Glu(666)-Glu(672) to exosite I. These findings were confirmed in a second, medium-resolution structure of FVa2 bound to the benzamidine-inhibited proteinase. Our results suggest that the acidic A2-B domain linker is involved in major interactions with thrombin during cofactor activation, with its more N-terminal hirudin-like sequence playing a critical role. Modeling experiments indicate that FVa2, and likely also FVa3, wrap around thrombin in productive thrombin·FV complexes that cover a large surface of the activator to engage the active site.
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A membrane-interactive surface on the factor VIII C1 domain cooperates with the C2 domain for cofactor function. Blood 2011; 117:3181-9. [DOI: 10.1182/blood-2010-08-301663] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Factor VIII binds to phosphatidylserine (PS)-containing membranes through its tandem, lectin-homology, C1 and C2 domains. However, the details of C1 domain membrane binding have not been delineated. We prepared 4 factor VIII C1 mutations localized to a hypothesized membrane-interactive surface (Arg2090Ala/Gln2091Ala, Lys2092Ala/Phe2093Ala, Gln2042Ala/Tyr2043Ala, and Arg2159Ala). Membrane binding and cofactor activity were measured using membranes with 15% PS, mimicking platelets stimulated by thrombin plus collagen, and 4% PS, mimicking platelets stimulated by thrombin. All mutants had at least 10-fold reduced affinities for membranes of 4% PS, and 3 mutants also had decreased apparent affinity for factor X. Monoclonal antibodies against the C2 domain produced different relative impairment of mutants compared with wild-type factor VIII. Monoclonal antibody ESH4 decreased the Vmax for all mutants but only the apparent membrane affinity for wild-type factor VIII. Monoclonal antibody BO2C11 decreased the Vmax of wild-type factor VIII by 90% but decreased the activity of 3 mutants more than 98%. These results identify a membrane-binding face of the factor VIII C1 domain, indicate an influence of the C1 domain on factor VIII binding to factor X, and indicate that cooperation between the C1 and C2 domains is necessary for full activity of the factor Xase complex.
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Complex assemblies of factors IX and X regulate the initiation, maintenance, and shutdown of blood coagulation. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2011; 99:51-103. [PMID: 21238934 DOI: 10.1016/b978-0-12-385504-6.00002-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Blood hemostasis is accomplished by a complex network of (anti-)coagulatory and fibrinolytic processes. These physiological processes are implemented by the assembly of multiprotein complexes involving both humoral and cellular components. Coagulation factor X, and particularly, factor IX, exemplify the dramatic enhancement that is obtained by the synergistic interaction of cell surface, inorganic and protein cofactors, protease, and substrate. With a focus on structure-function relationship, we review the current knowledge of activity modulation principles in the coagulation proteases factors IX and X and indicate future challenges for hemostasis research. This chapter is organized by describing the principles of hierarchical activation of blood coagulation proteases, including endogenous and exogenous protease activators, cofactor binding, substrate specificities, and protein inhibitors. We conclude by outlining pharmaceutical opportunities for unmet needs in hemophilia and thrombosis.
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Soeda T, Nogami K, Matsumoto T, Ogiwara K, Shima M. Mechanisms of factor VIIa-catalyzed activation of factor VIII. J Thromb Haemost 2010; 8:2494-503. [PMID: 20735721 DOI: 10.1111/j.1538-7836.2010.04042.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND Factor (F)VIIa, complexed with tissue factor (TF), is a primary trigger of blood coagulation, and has extremely restricted substrate specificity. The complex catalyzes limited proteolysis of FVIII, but these mechanisms are poorly understood. OBJECTIVES In the present study, we investigated the precise mechanisms of FVIIa/TF-catalyzed FVIII activation. RESULTS FVIII activity increased ~4-fold within 30 s in the presence of FVIIa/TF, and then decreased to initial levels within 20 min. FVIIa (0.1 nM), at concentrations present physiologically in plasma, activated FVIII in the presence of TF, and this activation was more rapid than that induced by thrombin. The heavy chain (HCh) of FVIII was proteolyzed at Arg(740) and Arg(372) more rapidly by FVIIa/TF than by thrombin, consistent with the enhanced activation of FVIII. Cleavage at Arg(336) was evident at ~1 min, whilst little cleavage of the light chain (LCh) was observed. Cleavage of the HCh by FVIIa/TF was governed by the presence of the LCh. FVIII bound to Glu-Gly-Arg-active-site-modified FVIIa (K(d), ~0.8 nM) with a higher affinity for the HCh than for the LCh (K(d), 5.9 and 18.9 nm). Binding to the A2 domain was particularly evident. Von Willebrand factor (VWF) modestly inhibited FVIIa/TF-catalyzed FVIII activation, in keeping with the concept that VWF could moderate FVIIa/TF-mediated reactions. CONCLUSIONS The results demonstrated that this activation mechanism was distinct from those mediated by thrombin, and indicated that FVIIa/TF functions through a 'priming' mechanism for the activation of FVIII in the initiation phase of coagulation.
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Affiliation(s)
- T Soeda
- Department of Pediatrics, Nara Medical University, Kashihara, Nara, Japan
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27
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Abstract
Mild hemophilia A (HA), defined by clinical features and factor VIII coagulant activity (FVIII:C) between 0.05 and 0.40 IU mL(-1), is characteristically distinct from severe HA. Indeed, although the molecular characterization of mild HA has permitted the identification of specific underlying mutations, its clinical phenotype is strikingly different from that of patients with a severe FVIII defect, where spontaneous hemorrhages or recurrent joint bleeding are usual manifestations. With aging, mild HA patients may develop complications (i.e. cancers and cardiovascular disorders), the management of which may prove challenging due to the concomitant bleeding tendency. Furthermore, the development of inhibitors provides an additional major complication in these patients, because it increases the severity of the bleeding phenotype and complicates their management. Standard management of mild HA includes the use of desmopressin and antifibrinolytic agents for minor bleeding episodes or surgical procedures, whilst major bleeding or surgery requires replacement therapy with FVIII concentrates. As regards treatment of patients with inhibitors, bypassing agents (i.e. activated prothrombin complex concentrates and recombinant activated FVII) have proven effective in the treatment of bleeding episodes, but as there are insufficient data to determine the optimal approach to immune tolerance induction in this group of patients, their optimal management remains controversial. Rituximab is a newer, promising therapeutic option for inhibitor eradication in such patients. Many aspects concerning mild HA remain to be clarified, including the molecular basis, the natural history and the optimal diagnostic and therapeutic strategies. Only large prospective studies will shed light on this condition.
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Affiliation(s)
- M Franchini
- Servizio di Immunoematologia e Medicina Trasfusionale, Dipartimento di Patologia e Medicina di Laboratorio, Azienda Ospedaliero-Universitaria di Parma, Parma, Italy.
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Patsialas K, Koutsas C, Makris P, Liakopoulou-Kyriakides M. Peptide analogues of 1811–1818 loop of the A3 subunit of the light chain A3-C1–C2 of FVIII of blood coagulation: biological evaluation. Amino Acids 2010; 39:481-8. [DOI: 10.1007/s00726-009-0464-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Accepted: 12/22/2009] [Indexed: 10/19/2022]
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Characteristics, mechanisms of action, and epitope mapping of anti-factor VIII antibodies. Clin Rev Allergy Immunol 2009; 37:67-79. [PMID: 19172415 DOI: 10.1007/s12016-009-8119-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The development of anti-factor VIII (FVIII) antibodies (Abs), also called inhibitors, is currently one of the most serious complications arising during the treatment of hemophilia A patients. Improved prevention and eradication of these Abs remain a challenge both for clinicians and scientists. Numerous studies in the literature have reported on their epitope specificity, on their mechanism of FVIII inactivation, as well as on the methods used for their detection. In this review, we summarize the current knowledge on the nature (isotypes, kinetic properties), epitope properties, and mechanisms of action of anti-FVIII Abs. Furthermore, we present methods for detection and epitope characterization of anti-FVIII Abs with emphasis on the Luminex technique susceptible to facilitate the monitoring of changes in the epitope specificity of these Abs.
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30
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Jagannathan I, Ichikawa HT, Kruger T, Fay PJ. Identification of residues in the 558-loop of factor VIIIa A2 subunit that interact with factor IXa. J Biol Chem 2009; 284:32248-55. [PMID: 19801661 DOI: 10.1074/jbc.m109.050781] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Factor VIIIa is comprised of A1, A2, and A3C1C2 subunits. Several lines of evidence have identified the A2 558-loop as interacting with factor IXa. The contributions of individual residues within this region to inter-protein affinity and cofactor activity were assessed following alanine scanning mutagenesis of residues 555-571 that border or are contained within the loop. Variants were expressed as isolated A2 domains in Sf9 cells using a baculovirus construct and purified to >90%. Two reconstitution assays were employed to determine affinity and activity parameters. The first assay reconstituted factor Xase using varying concentrations of A2 mutant and fixed levels of A1/A3C1C2 dimer purified from wild type (WT), baby hamster kidney cell-expressed factor VIII, factor IXa, and phospholipid vesicles to determine the inter-molecular K(d) for A2. The second assay determined the K(d) for A2 in factor VIIIa by reconstituting various A2 and fixed levels of A1/A3C1C2. Parameter values were determined by factor Xa generation assays. WT A2 expressed in insect cells yielded similar K(d) and k(cat) values following reconstitution as WT A2 purified from baby hamster kidney cell-expressed factor VIII. All A2 variants exhibited modest if any increases in K(d) values for factor VIIIa assembly. However, variants S558A, V559A, D560A, G563A, and I566A showed >9-fold increases in K(d) for factor Xase assembly, implicating these residues in stabilizing A2 association with factor IXa. Furthermore, variants Y555A, V559A, D560A, G563A, I566A, and D569A showed >80% reduction in k(cat) for factor Xa generation. These results identify residues in the 558-loop critical to interaction with factor IXa in Xase.
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Affiliation(s)
- Indu Jagannathan
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine, Rochester, New York 14642, USA
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Factor VIII C1 domain residues Lys 2092 and Phe 2093 contribute to membrane binding and cofactor activity. Blood 2009; 114:3938-46. [PMID: 19687511 DOI: 10.1182/blood-2009-01-197707] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Binding of factor VIII to membranes containing phosphatidyl-L-serine (Ptd-L-Ser) is mediated, in part, by a motif localized to the C2 domain. We evaluated a putative membrane-binding role of the C1 domain using an anti-C1 antibody fragment, KM33(scFv), and factor VIII mutants with an altered KM33 epitope. We prepared a dual mutant Lys2092/Phe2093 --> Ala/Ala (fVIII(YFP 2092/93)) and 2 single mutants Lys2092 --> Ala and Phe2093 --> Ala. KM33(scFv) inhibited binding of fluorescein-labeled factor VIII to synthetic membranes and inhibited at least 95% of factor Xase activity. fVIII(YFP 2092/93) had 3-fold lower affinity for membranes containing 15% Ptd-L-Ser but more than 10-fold reduction in affinity for membranes with 4% Ptd-L-Ser. In a microtiter plate, KM33(scFv) was additive with an anti-C2 antibody for blocking binding to vesicles of 15% Ptd-L-Ser, whereas either antibody blocked binding to vesicles of 4% Ptd-L-Ser. KM33(scFv) inhibited binding to platelets and fVIII(YFP 2092/93) had reduced binding to A23187-stimulated platelets. fVIII(YFP 2092) exhibited normal activity at various Ptd-L-Ser concentrations, whereas fVIII(YFP 2093) showed a reduction of activity with Ptd-L-Ser less than 12%. fVIII(YFP 2092/93) had a greater reduction of activity than either single mutant. These results indicate that Lys 2092 and Phe 2093 are elements of a membrane-binding motif on the factor VIII C1 domain.
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Terraube V, O'Donnell JS, Jenkins PV. Factor VIII and von Willebrand factor interaction: biological, clinical and therapeutic importance. Haemophilia 2009; 16:3-13. [PMID: 19473409 DOI: 10.1111/j.1365-2516.2009.02005.x] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The interaction of factor VIII (FVIII) with von Willebrand Factor (VWF) is of direct clinical significance in the diagnosis and treatment of patients with haemophilia A and von Willebrand disease (VWD). A normal haemostatic response to vascular injury requires both FVIII and VWF. It is well-established that in addition to its role in mediating platelet to platelet and platelet to matrix binding, VWF has a direct role in thrombin and fibrin generation by acting as a carrier molecule for the cofactor FVIII. Recent studies show that the interaction affects not only the biology of both FVIII and VWF, and the pathology of haemophilia and VWD, but also presents opportunities in the treatment of haemophilia. This review details the mechanisms and the molecular determinants of FVIII interaction with VWF, and the role of FVIII-VWF interaction in modulating FVIII interactions with other proteases, cell types and cellular receptors. The effect of defective interaction of FVIII with VWF as a result of mutations in either protein is discussed.
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Affiliation(s)
- V Terraube
- Haemostasis Research Group, Institute of Molecular Medicine, Trinity College, Dublin, Ireland
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Pratt KP, Thompson AR. B-Cell and T-Cell Epitopes in Anti-factor VIII Immune Responses. Clin Rev Allergy Immunol 2009; 37:80-95. [DOI: 10.1007/s12016-009-8120-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Nogami K, Nishiya K, Saenko EL, Takeyama M, Ogiwara K, Yoshioka A, Shima M. Identification of plasmin-interactive sites in the light chain of factor VIII responsible for proteolytic cleavage at Lys36. J Biol Chem 2009; 284:6934-45. [PMID: 19126539 DOI: 10.1074/jbc.m802224200] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have recently reported that plasmin likely associates with the factor VIII light chain to proteolyze at Lys36 within the A1 domain. In this study, we determined that the rate of plasmin-catalyzed inactivation on the forms of factor VIIIa containing A1-(1-336) and 1722A3C1C2, reflecting Lys36 cleavage, was reduced by approximately 60%, compared with those containing 1649A3C1C2 and 1690A3C1C2. SDS-PAGE analysis revealed that Lys36 cleavage of factor VIIIa with 1722A3C1C2 was markedly slower than those with 1649A3C1C2 and 1690A3C1C2. Surface plasmon resonance-based assays, using active site-modified anhydro-plasmin (Ah-plasmin) showed that 1722A3C1C2 bound to Ah-plasmin with an approximately 3-fold lower affinity than 1649A3C1C2 or 1690A3C1C2 (Kd, 176, 68.2, and 60.3 nM, respectively). Recombinant A3 bound to Ah-plasmin (Kd, 44.2 nM), whereas C2 failed to bind, confirming the presence of a plasmin-binding site within N terminus of A3. Furthermore, the Glu-Gly-Arg active site-modified factor IXa also blocked 1722A3C1C2 binding to Ah-plasmin by approximately 95%, supporting the presence of another plasmin-binding site overlapping the factor IXa-binding site in A3. In keeping with a major contribution of the lysine-binding sites in plasmin for interaction with the factor VIII light chain, analysis of the A3 sequence revealed two regions involving clustered lysine residues in 1690-1705 and 1804-1818. Two peptides based on these regions blocked 1649A3C1C2 binding to Ah-plasmin by approximately 60% and plasmin-catalyzed Lys36 cleavage of factor VIIIa with A1-(1-336) by approximately 80%. Our findings indicate that an extended surface, centered on residues 1690-1705 and 1804-1818 within the A3 domain, contributes to a unique plasmin-interactive site that promotes plasmin docking during cofactor inactivation by cleavage at Lys36.
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Affiliation(s)
- Keiji Nogami
- Department of Pediatrics, Nara Medical University, Kashihara, Nara 634-8522, Japan.
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Takeyama M, Nogami K, Saenko EL, Soeda T, Nishiya K, Ogiwara K, Yoshioka A, Shima M. Protein S down-regulates factor Xase activity independent of activated protein C: specific binding of factor VIII(a) to protein S inhibits interactions with factor IXa. Br J Haematol 2008; 143:409-20. [DOI: 10.1111/j.1365-2141.2008.07366.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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36
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Crystal structure of human factor VIII: implications for the formation of the factor IXa-factor VIIIa complex. Structure 2008; 16:597-606. [PMID: 18400180 DOI: 10.1016/j.str.2008.03.001] [Citation(s) in RCA: 167] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2008] [Revised: 02/27/2008] [Accepted: 03/01/2008] [Indexed: 11/24/2022]
Abstract
Factor VIII is a procofactor that plays a critical role in blood coagulation, and is missing or defective in hemophilia A. We determined the X-ray crystal structure of B domain-deleted human factor VIII. This protein is composed of five globular domains and contains one Ca(2+) and two Cu(2+) ions. The three homologous A domains form a triangular heterotrimer where the A1 and A3 domains serve as the base and interact with the C2 and C1 domains, respectively. The structurally homologous C1 and C2 domains reveal membrane binding features. Based on biochemical studies, a model of the factor IXa-factor VIIIa complex was constructed by in silico docking. Factor IXa wraps across the side of factor VIII, and an extended interface spans the factor VIII heavy and light chains. This model provides insight into the activation of factor VIII and the interaction of factor VIIIa with factor IXa on the membrane surface.
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Steen M, Tran S, Autin L, Villoutreix BO, Tholander AL, Dahlbäck B. Mapping of the factor Xa binding site on factor Va by site-directed mutagenesis. J Biol Chem 2008; 283:20805-12. [PMID: 18502757 DOI: 10.1074/jbc.m802703200] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Activated coagulation factor V functions as a cofactor to factor Xa in the conversion of prothrombin to thrombin. Based on the introduction of extra carbohydrate side chains in recombinant factor V, we recently proposed several regions in factor Va to be important for factor Xa binding. To further define which residues are important for factor Xa binding, we prepared fifteen recombinant factor V variants in which clusters of charged amino acid residues were mutated, mainly to alanines. The factor V variants were expressed in COS-1 cells, and their functional properties evaluated in a prothrombinase-based assay, as well as in a direct binding test. Four of the factor V variants, 501A/510A/511D, 501A/510A/511D/513A, 513A/577A/578A, and 501A/510A/511D/513A/577A/578A exhibited markedly reduced factor Xa-cofactor activity tested in the prothrombinase assay, and reduced binding affinity as judged by the direct binding assay. These factor Va variants were normally cleaved at Arg-506 by activated protein C, and the interaction between the factor Xa-factor Va complex and prothrombin was unaffected by the introduced mutations. Based on the integration of all available data, we propose a key factor Xa binding surface to be centered on Arg-501, Arg-510, Ala-511, Asp-513, Asp-577, and Asp-578 in the factor Va A2 domain. These residues form an elongated charged factor Xa binding cluster on the factor Va surface.
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Affiliation(s)
- Mårten Steen
- Department of Laboratory Medicine, Division of Clinical Chemistry, Lund University, The Wallenberg Laboratory, MAS, SE-205 02 Malmö, Sweden
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Gale AJ, Yegneswaran S, Xu X, Pellequer JL, Griffin JH. Characterization of a factor Xa binding site on factor Va near the Arg-506 activated protein C cleavage site. J Biol Chem 2007; 282:21848-55. [PMID: 17553804 DOI: 10.1074/jbc.m702192200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Prothrombin is proteolytically activated by the prothrombinase complex comprising the serine protease Factor (F) Xa complexed with its cofactor, FVa. Based on inhibition of the prothrombinase complex by synthetic peptides, FVa residues 493-506 were proposed as a FXa binding site. FVa is homologous to FVIIIa, the cofactor for the FIXa protease, in the FX-activating complex, and FVIIIa residues 555-561 (homologous to FVa residues 499-506) are recognized as a FIXa binding sequence. To test the hypothesis that FVa residues 499-505 contribute to FXa binding, we created the FVa loop swap mutant (designated 499-505(VIII) FV) with residues 499-505 replaced by residues 555-561 of FVIIIa, which differ at five of seven positions. Based on kinetic measurements and spectroscopic titrations, this FVa loop swap mutant had significantly reduced affinity for FXa. The fully formed prothrombinase complex containing this FVa mutant had fairly normal kinetic parameters (k(cat) and K(m)) for cleavage of prothrombin at Arg-320. However, small changes in both Arg-320 and Arg-271 cleavage rates result together in a moderate change in the pathway of prothrombin activation. Although residues 499-505 directly precede the Arg-506 cleavage site for activated protein C (APC), the 499-505(VIII) FVa mutant was inactivated entirely normally by APC. These results suggest that this A2 domain sequence of the FVa and FVIIIa cofactors evolved to have different specificity for binding FXa and FIXa while retaining compatibility as substrate for APC. In an updated three-dimensional model for the FVa structure, residues 499-505, along with Arg-506, Arg-306, and other previously suggested FXa binding sequences, delineate a continuous surface on the A2 domain that is strongly implicated as an extended FXa binding surface in the prothrombinase complex.
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Affiliation(s)
- Andrew J Gale
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA.
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Fang H, Wang L, Wang H. The protein structure and effect of factor VIII. Thromb Res 2007; 119:1-13. [PMID: 16487577 DOI: 10.1016/j.thromres.2005.12.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2005] [Revised: 11/06/2005] [Accepted: 12/26/2005] [Indexed: 11/23/2022]
Abstract
Factor VIII (FVIII) is a key component of the fluid phase of the blood coagulation system. The proteases efficiently cleave FVIII at three sites, two within the heavy and one within the light chain resulting in alteration of its covalent structure and conformation and yielding the active cofactor, FVIIIa. FVIIIa is a trimer composed of A1, A2 and A3-C1-C2 subunits. The role of FVIIIa is to markedly increase the catalytic efficiency of factor IXa in the activation of factor X. Variants of these factors frequently also lead to severe bleeding disorders.
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Affiliation(s)
- Hong Fang
- Department of Cardiology, Tongji Hospital, Tongji University, Shanghai 200065, China.
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41
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Di Giambattista M, Branckaert T, Hougardy V, Kemball-Cook G, Laub R. In silico prediction of FVIII epitopes recognised by natural autoantibodies in polyvalent immunoglobulin concentrates. Mol Immunol 2006; 44:1903-13. [PMID: 17113150 DOI: 10.1016/j.molimm.2006.09.034] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2006] [Accepted: 09/29/2006] [Indexed: 11/15/2022]
Abstract
Inhibitory antibodies directed against blood coagulation factor VIII (FVIII) impair FVIII replacement therapy, constituting a serious complication in haemophilic and autoimmune patients. Identifying B-cell FVIII epitopes and mapping them on the molecule remain important challenges. Using a combination of different algorithms, more than 30 hypothetical linear epitopes were predicted on the FVIII molecule surface. We selected several major predicted sequences, spanning all FVIII domains, for specific antibody induction in rabbits. All peptides tested successfully induced production of specific anti-FVIII rabbit antibodies, supporting the relevance of our approach. To investigate the presence of FVIII-reactive antibodies in the healthy donor population, a pooled fraction rich in all IgG subclasses was purified on peptide-Sepharose columns. Substantial amounts of Ig, specific for each FVIII peptide, were purified with yields ranging from 8 to 223 ng/mg immunoglobulins. Our results confirm the diversity of FVIII epitopes recognised by natural human anti-FVIII autoantibodies. All IgG subclasses were found in the affinity-isolated anti-peptide material, with overrepresentation of IgG2 and IgG4. Evidence was also found for new FVIII epitopes. Five human anti-peptide preparations displayed FVIII-neutralising activity, ranging from 1.3 to 5.3 BU/mg. Although the presence of naturally occurring anti-FVIII antibodies in healthy donors has been previously described, our methodology has allowed, for the first time, a fine mapping of several inhibitory and non-inhibitory epitopes. Our observations support the hypothesis that FVIII inhibitors in haemophilia A and autoimmune disease may originate from the proliferation of natural FVIII-specific B-cell clones.
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Affiliation(s)
- Mario Di Giambattista
- Research & Development Unit, Central Department for Fractionation, Avenue de Tyras 109, Red Cross, B-1120 Brussels, Belgium
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42
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SAENKO EL, ANANYEVA NM. Receptor-mediated clearance of factor VIII: implications for pharmacokinetic studies in individuals with haemophilia. Haemophilia 2006. [DOI: 10.1111/j.1365-2516.2006.01329.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Autin L, Steen M, Dahlbäck B, Villoutreix BO. Proposed structural models of the prothrombinase (FXa-FVa) complex. Proteins 2006; 63:440-50. [PMID: 16437549 DOI: 10.1002/prot.20848] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Activated coagulation factor V (FVa) functions as a cofactor to factor Xa (FXa) in the conversion of prothrombin (PT) to thrombin. This essential procoagulant reaction, despite being the subject of extensive investigation, is not fully understood structurally and functionally. To elucidate the structure of the FXa-FVa complex, we have performed protein:protein (Pr:Pr) docking simulation with the pseudo-Brownian Pr:Pr docking ICM package and with the shape-complementarity Pr:Pr docking program PPD. The docking runs were carried out using a new model of full-length human FVa and the X-ray structure of human FXa. Five representative models of the FXa-FVa complex were in overall agreement with some of the available experimental data, but only one model was found to be consistent with almost all of the reported experimental results. The use of hybrid docking approach (theoretical plus experimental) is definitively important to study such large macromolecular complexes. The FXa-FVa model we have created will be instrumental for further investigation of this macromolecular system and will guide future site directed mutagenesis experiments.
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Abstract
The reduced mortality, improved joint outcomes and enhanced quality of life, which have been witnessed in the developed world for patients with haemophilia, have been an outstanding achievement. Advancements in biotechnology contributed significantly through the development of improved pathogen screening, viral inactivation techniques and the development of recombinant clotting factors. These were partnered with enhanced delivery of care through comprehensive haemophilia centres, adoption of home therapy and most recently effective prophylaxis. This came at great costs to governments, medical insurers and patients' families. In addition, barriers persist limiting the adoption and adherence of effective prophylactic therapy. Biotechnology has been successful at overcoming similar barriers in other disease states. Long-acting biological therapeutics are an incremental advance towards overcoming some of these barriers. Strategies that have been successful for other therapeutic proteins are now being applied to factor VIII (FVIII) and include modifications such as the addition of polyethylene glycol (PEG) polymers and polysialic acids and alternative formulation with PEG-modified liposomes. In addition, insight into FVIII structure and function has allowed targeted modifications of the protein to increase the duration of its cofactor activity and reduce its clearance in vivo. The potential advantages and disadvantages of these approaches will be discussed.
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Affiliation(s)
- E L Saenko
- Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, MD, USA
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45
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Gale AJ, Radtke KP, Cunningham MA, Chamberlain D, Pellequer JL, Griffin JH. Intrinsic stability and functional properties of disulfide bond-stabilized coagulation factor VIIIa variants. J Thromb Haemost 2006; 4:1315-22. [PMID: 16706977 DOI: 10.1111/j.1538-7836.2006.01951.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND The utility of purified coagulation factor (F)VIII for treatment of hemophilia A is limited in part by its instability following activation by thrombin, which is caused by spontaneous dissociation of the A2 domain from the activated FVIII (FVIIIa) heterotrimer. To prevent this A2 domain dissociation in FVIIIa, we previously engineered a cysteine pair (C664-C1826) in recombinant FVIII that formed a disulfide bond cross-linking the A2 domain in the heavy chain to the A3 domain in the light chain. This engineered disulfide bond resulted in a more stable FVIIIa. AIMS Here, we characterize the functional parameters of C664-C1828 FVIII and of a new disulfide bond-stabilized FVIII (C662-C1828 FVIII). METHODS In order to assess whether these FVIII variants might be good candidates for a new therapeutic agent to treat hemophilia A, we investigated a variety of functional parameters that might affect the in vivo properties of the variants, including half-life of disulfide bond-stabilized FVIII and FVIIIa and the potency of these FVIIIa molecules in the FXase complex. RESULTS Both disulfide bond-stabilized variants had improved affinity for von Willebrand factor (VWF). In studies of FX activation by purified FIXa and FVIIIa, C662-C1828 FVIIIa had normal activity while C664-C1826 FVIIIa had reduced activity. Both C664-C1826 FVIIIa and C662-C1828 FVIIIa were inactivated by activated protein C (APC) but the rates of inactivation were different. CONCLUSION Overall, the specific location of the disulfide bridge between the A2 and A3 domains appears to affect functional properties of FVIIIa. In summary, introduction of engineered interdomain disulfides results in FVIIIa variants that resist spontaneous loss of activity while retaining susceptibility to APC proteolytic inactivation and maintaining VWF binding.
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Affiliation(s)
- A J Gale
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA.
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46
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Sheehan JP, Walke EN. Depolymerized holothurian glycosaminoglycan and heparin inhibit the intrinsic tenase complex by a common antithrombin-independent mechanism. Blood 2006; 107:3876-82. [PMID: 16672689 PMCID: PMC1895295 DOI: 10.1182/blood-2005-07-3043] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Depolymerized holothurian glycosaminoglycan (DHG) is a fucosylated chrondroitin sulfate that possesses antithrombin-independent antithrombotic properties and inhibits factor X activation by the intrinsic tenase complex (factor IXa-factor VIIIa). The mechanism and molecular target for intrinsic tenase inhibition were determined and compared with inhibition by low-molecular-weight heparin (LMWH). DHG inhibited factor X activation in a noncompetitive manner (reduced V(max(app))), with 50-fold higher apparent affinity than LMWH. DHG did not affect factor VIIIa half-life or chromogenic substrate cleavage by factor IXa-phospholipid but reduced the affinity of factor IXa for factor VIIIa. DHG competed factor IXa binding to immobilized LMWH with an EC(50) 35-fold lower than soluble LWMH. Analysis of intrinsic tenase inhibition, employing factor IXa with mutations in the heparin-binding exosite, demonstrated that relative affinity (K(i)) for DHG was as follows: wild type > K241A > H92A > R170A > > R233A, with partial rather than complete inhibition of the mutants. This rank order for DHG potency correlated with the effect of these mutations on factor IXa-LMWH affinity and the potency of LMWH for intrinsic tenase. DHG also accelerated decay of the intact intrinsic tenase complex. Thus, DHG binds to an exosite on factor IXa that overlaps with the binding sites for LMWH and factor VIIIa, disrupting critical factor IXa-factor VIIIa interactions.
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Affiliation(s)
- John P Sheehan
- Department of Medicine/Hematology, University of Wisconsin, Medical Sciences Center Rm. 4285, 1300 University Avenue, Madison, WI 53706, USA.
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47
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Boekhorst J, Verbruggen B, Lavergne JM, Costa JM, Schoormans SCM, Brons PPT, van Kraaij MGJ, Nováková IRO, van Heerde WL. Thirteen novel mutations in the factor VIII gene in the Nijmegen haemophilia A patient population. Br J Haematol 2005; 131:109-17. [PMID: 16173970 DOI: 10.1111/j.1365-2141.2005.05737.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The development of neutralising antibodies to factor VIII (FVIII) is a major complication of haemophilia A (HA) therapy. We aimed to construct an individual risk profile for the development of inhibitors in HA and started by screening for the causative mutation in our HA patient population. A total of 109 patients and 28 carriers were screened. The analysis revealed 38 different mutations in the FVIII gene, of which 13 have not been described on the Haemophilia A Mutation, Search, Test and Resource Site (HAMSTeRS). Twenty-five mutations have been reported previously and all except two had a similar phenotype to what has been described. Three novel mutations were associated with severe HA: one non-missense mutation, a small insertion in the A2 domain, and two missense mutations, a H256R mutation in the A1 domain and a L2025P substitution in the C1 domain. One novel mutation, Y156C, was associated with moderate HA. Nine novel mutations caused mild HA. The P130R, D167E and V278M mutations are located in the A1 domain. R439C, Y511H, A544G and Q645H in the A2 domain, L1758F in the A3 domain and a S2157R mutation in the C1 domain. In conclusion, the genotypic profile of our HA population was not different from others described and is suitable to study inhibitor formation.
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Affiliation(s)
- Jorien Boekhorst
- Department of Haematology, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands.
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48
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Autin L, Miteva MA, Lee WH, Mertens K, Radtke KP, Villoutreix BO. Molecular models of the procoagulant factor VIIIa-factor IXa complex. J Thromb Haemost 2005; 3:2044-56. [PMID: 16102111 DOI: 10.1111/j.1538-7836.2005.01527.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Formation of the intrinsic tenase complex is an essential event in the procoagulant reactions that lead to clot formation. The tenase complex is formed when the activated serine protease, Factor IXa (FIXa), and its cofactor Factor VIIIa (FVIIIa) assemble on a phospholipid surface to proteolytically convert the zymogen Factor X (FX) into its active form FXa. The physiological relevance of the tenase complex is evident in hemophilia A or B patients who present with bleeding disorders. OBJECTIVES The purpose of this study was to establish three-dimensional (3D) models of the FVIIIa-FIXa complex. METHODS First, we built two new theoretical models of FVIIIa via homology modeling, inter-domain docking and loop simulation algorithms as well as a model for FIXa. This was followed by pseudo-Brownian protein-protein docking in internal coordinates with the ICM (Internal Coordinates Mechanics) program between the two FVIIIa and the FIXa structures. RESULTS Ten representative models of this complex are presented based on agreements with known experimental data and according to structural criteria. CONCLUSIONS These novel 3D models will help guide future site directed mutagenesis aimed at improving the functionality of FVIIIa and/or FIXa and will contribute to a better understanding of the role of this macromolecular complex in the blood coagulation cascade.
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Affiliation(s)
- L Autin
- Inserm U648, Paris 5 University, 4 Ave de l'Observatoire, Paris, France
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49
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Abstract
Factor VIII, a metal ion-dependent heterodimer, circulates in complex with von Willebrand factor. At sites of vessel wall damage, this procofactor is activated to factor VIIIa by limited proteolysis and assembles onto an anionic phospholipid surface in complex with factor IXa to form the intrinsic factor Xase; an enzyme complex that efficiently converts factor X to factor Xa during the propagation phase of coagulation. Factor Xase activity is down-regulated by mechanisms that include self-dampening by dissociation of a critical factor VIIIa subunit and proteolytic inactivation by the activated protein C pathway. Recent studies identify putative metal ion coordination sites as well as ligands involved in the catabolism of the activated and procofactor forms of the protein. Our knowledge of these multiple intra- and inter-molecular interactions has been facilitated by the application of naturally occurring and site-directed mutations to study factor VIII structure and function. In this review, we document important and novel contributions following this line of investigation.
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Affiliation(s)
- Philip J Fay
- Department of Biochemistry, School of Medicine, University of Rochester, P.O. Box 712, 601 Elmwood Ave., Rochester, NY 14642, USA.
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50
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Bos MHA, Meijerman DWE, van der Zwaan C, Mertens K. Does activated protein C-resistant factor V contribute to thrombin generation in hemophilic plasma? J Thromb Haemost 2005; 3:522-30. [PMID: 15748243 DOI: 10.1111/j.1538-7836.2005.01181.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this study we assessed the role of factor V (FV) inactivation in hemophilic plasma with particular reference to the activated protein C (APC)-resistant variants FV-R506Q (FV Leiden) and FV-R306T (FV Cambridge). Purified recombinant full-length FV carrying these single substitutions and FV-R306T/R506Q were used in thrombin generation experiments. Plasma was first immunodepleted of FV, and subsequently of factors VIII, IX, or combinations thereof. Thrombin generation was initiated by low concentrations of recombinant tissue factor. Recombinant soluble thrombomodulin (TM) was used to trigger the APC system. Surprisingly, TM concentrations that reduced thrombin generation in normal plasma by no more than 50% virtually abolished thrombin formation in plasma deficient in the factor VIII/IX complex. This was already apparent at TM levels as low as 0.1 nmol L(-1). By varying the concentrations of purified (activated) protein C to plasma that was additionally depleted of protein C, we confirmed that impaired thrombin generation indeed was the result of the action of APC. In contrast, this did not occur when FV-depleted plasma had been reconstituted with FV-R306T/R506Q. Addition of FV-R306T or FV-R506Q partially reduced prothrombin activation, demonstrating the involvement of both APC cleavage sites. FV inactivation also occurred on the surface of human microvascular endothelial cells. Apparently, these cells express sufficient TM to down-regulate thrombin production via the APC pathway. We further conclude that in hemophilic plasma this pathway can induce a secondary defect because of premature FV inactivation. It therefore seems conceivable that APC-resistant FV has the potential of alleviating hemophilic bleeding.
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Affiliation(s)
- M H A Bos
- The Department of Plasma Proteins, Sanquin Research at CLB, Amsterdam, the Netherlands
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