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Pablo-Moreno JAD, Serrano LJ, Revuelta L, Sánchez MJ, Liras A. The Vascular Endothelium and Coagulation: Homeostasis, Disease, and Treatment, with a Focus on the Von Willebrand Factor and Factors VIII and V. Int J Mol Sci 2022; 23:ijms23158283. [PMID: 35955419 PMCID: PMC9425441 DOI: 10.3390/ijms23158283] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 07/22/2022] [Accepted: 07/23/2022] [Indexed: 11/27/2022] Open
Abstract
The vascular endothelium has several important functions, including hemostasis. The homeostasis of hemostasis is based on a fine balance between procoagulant and anticoagulant proteins and between fibrinolytic and antifibrinolytic ones. Coagulopathies are characterized by a mutation-induced alteration of the function of certain coagulation factors or by a disturbed balance between the mechanisms responsible for regulating coagulation. Homeostatic therapies consist in replacement and nonreplacement treatments or in the administration of antifibrinolytic agents. Rebalancing products reestablish hemostasis by inhibiting natural anticoagulant pathways. These agents include monoclonal antibodies, such as concizumab and marstacimab, which target the tissue factor pathway inhibitor; interfering RNA therapies, such as fitusiran, which targets antithrombin III; and protease inhibitors, such as serpinPC, which targets active protein C. In cases of thrombophilia (deficiency of protein C, protein S, or factor V Leiden), treatment may consist in direct oral anticoagulants, replacement therapy (plasma or recombinant ADAMTS13) in cases of a congenital deficiency of ADAMTS13, or immunomodulators (prednisone) if the thrombophilia is autoimmune. Monoclonal-antibody-based anti-vWF immunotherapy (caplacizumab) is used in the context of severe thrombophilia, regardless of the cause of the disorder. In cases of disseminated intravascular coagulation, the treatment of choice consists in administration of antifibrinolytics, all-trans-retinoic acid, and recombinant soluble human thrombomodulin.
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Affiliation(s)
- Juan A. De Pablo-Moreno
- Department of Genetics, Physiology and Microbiology, School of Biology, Complutense University, 28040 Madrid, Spain; (J.A.D.P.-M.); (L.J.S.)
| | - Luis Javier Serrano
- Department of Genetics, Physiology and Microbiology, School of Biology, Complutense University, 28040 Madrid, Spain; (J.A.D.P.-M.); (L.J.S.)
| | - Luis Revuelta
- Department of Physiology, School of Veterinary Medicine, Complutense University of Madrid, 28040 Madrid, Spain;
| | - María José Sánchez
- Centro Andaluz de Biología del Desarrollo (CABD), Consejo Superior de Investigaciones Científicas (CSIC), Junta de Andalucía, Pablo de Olavide University, 41013 Sevilla, Spain;
| | - Antonio Liras
- Department of Genetics, Physiology and Microbiology, School of Biology, Complutense University, 28040 Madrid, Spain; (J.A.D.P.-M.); (L.J.S.)
- Correspondence:
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Mashausi DS, Roy D, Mangukiya HB, Merugu SB, Raza G, Yunus FUN, Liu GS, Negi H, Li D. A high efficient FVIII variant corrects bleeding in hemophilia A mouse model. Biochem Biophys Res Commun 2022; 637:358-364. [DOI: 10.1016/j.bbrc.2022.02.066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 02/17/2022] [Accepted: 02/18/2022] [Indexed: 11/02/2022]
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3
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Gong J, Chung TH, Zheng J, Zheng H, Chang LJ. Transduction of modified factor VIII gene improves lentiviral gene therapy efficacy for hemophilia A. J Biol Chem 2021; 297:101397. [PMID: 34774524 PMCID: PMC8649223 DOI: 10.1016/j.jbc.2021.101397] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 11/03/2021] [Accepted: 11/04/2021] [Indexed: 12/18/2022] Open
Abstract
Hemophilia A (HA) is a bleeding disorder caused by deficiency of the coagulation factor VIII (F8). F8 replacement is standard of care, whereas gene therapy (F8 gene) for HA is an attractive investigational approach. However, the large size of the F8 gene and the immunogenicity of the product present challenges in development of the F8 gene therapy. To resolve these problems, we synthesized a shortened F8 gene (F8-BDD) and cloned it into a lentiviral vector (LV). The F8-BDD produced mainly short cleaved inactive products in LV-transduced cells. To improve F8 functionality, we designed two novel F8-BDD genes, one with an insertion of eight specific N-glycosylation sites (F8-N8) and another which restored all N-glycosylation sites (F8-299) in the B domain. Although the overall protein expression was reduced, high coagulation activity (>100-fold) was detected in the supernatants of LV-F8-N8- and LV-F8-299-transduced cells. Protein analysis of F8 and the procoagulation cofactor, von Willebrand Factor, showed enhanced interaction after restoration of B domain glycosylation using F8-299. HA mouse hematopoietic stem cell transplantation studies illustrated that the bleeding phenotype was corrected after LV-F8-N8 or -299 gene transfer into the hematopoietic stem cells. Importantly, the F8-299 modification markedly reduced immunogenicity of the F8 protein in these HA mice. In conclusion, the modified F8-299 gene could be efficiently packaged into LV and, although with reduced expression, produced highly stable and functional F8 protein that corrected the bleeding phenotype without inhibitory immunogenicity. We anticipate that these results will be beneficial in the development of gene therapies against HA.
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Affiliation(s)
- Jie Gong
- School of Medicine, University of Electronic Science and Technology of China, Sichuan, China
| | - Tsai-Hua Chung
- School of Medicine, University of Electronic Science and Technology of China, Sichuan, China; Shenzhen Geno-Immune Medical Institute, Shenzhen, China
| | - Jie Zheng
- Hematology Center, Beijing Children's Hospital, Capital Medical University, Beijing, China
| | - Huyong Zheng
- Hematology Center, Beijing Children's Hospital, Capital Medical University, Beijing, China
| | - Lung-Ji Chang
- School of Medicine, University of Electronic Science and Technology of China, Sichuan, China; Shenzhen Geno-Immune Medical Institute, Shenzhen, China; Hematology Center, Beijing Children's Hospital, Capital Medical University, Beijing, China.
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4
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Jun Z, Ming-Ming L, Qian-Qing Z, Yun-Hong W, Chong-Yang Z, Xin L. Functional identification of factor VIII B domain regions in hepatocyte cells. Biochem Biophys Res Commun 2020; 526:633-640. [PMID: 32248973 DOI: 10.1016/j.bbrc.2020.03.132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 03/23/2020] [Indexed: 11/15/2022]
Abstract
Factor VIII (FVIII) functions as a cofactor within the intrinsic pathway of blood coagulation in process of FX activation by FIXa, for which deficiency results in the bleeding disorder hemophilia A. The gene of FVIII contains 26 exons that code for a 19 amino acid signal peptide and a 2332 amino acid polypeptide with a domain structure designated A1-A2-B-A3-C1-C2, of which the A domains are homologous with each other, as are the C domains. It has been well-documented that both the domains are the necessary elements for FVIII activities. The B domain is highly glycosylated and has a variable sequence, even among FVIIIs from different species. The B domain plays versatile roles in FVIII lifespan except for coagulation activity, but the functional characteristics of its specific regions remain still obscure. A series of recombinant FVIIIs (rFVIIIs) with B domain truncated were constructed and transiently expressed in hepatocyte cells. Media and cell lysates were collected after 72 h for the analyses of FVIII biosynthesis, secretion, activity and stability in ex vivo plasma relative to the full length wild-type FVIII. Unexpectedly, various regions in B domain exhibited different contribution to these functionalities. The discovery might facilitate the bioengineered rFVIIIs and gene therapeutics.
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Affiliation(s)
- Zhang Jun
- Institute of Molecular Medicine and Oncology, Chongqing Medical University, Chongqing, 400016, China.
| | - Lin Ming-Ming
- Institute of Molecular Medicine and Oncology, Chongqing Medical University, Chongqing, 400016, China
| | - Zhang Qian-Qing
- Institute of Molecular Medicine and Oncology, Chongqing Medical University, Chongqing, 400016, China
| | - Wang Yun-Hong
- Institute of Molecular Medicine and Oncology, Chongqing Medical University, Chongqing, 400016, China
| | - Zhu Chong-Yang
- Institute of Molecular Medicine and Oncology, Chongqing Medical University, Chongqing, 400016, China
| | - Li Xin
- Institute of Molecular Medicine and Oncology, Chongqing Medical University, Chongqing, 400016, China
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5
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Selective factor VIII activation by the tissue factor-factor VIIa-factor Xa complex. Blood 2017; 130:1661-1670. [PMID: 28729433 DOI: 10.1182/blood-2017-02-767079] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 07/06/2017] [Indexed: 12/23/2022] Open
Abstract
Safe and effective antithrombotic therapy requires understanding of mechanisms that contribute to pathological thrombosis but have a lesser impact on hemostasis. We found that the extrinsic tissue factor (TF) coagulation initiation complex can selectively activate the antihemophilic cofactor, FVIII, triggering the hemostatic intrinsic coagulation pathway independently of thrombin feedback loops. In a mouse model with a relatively mild thrombogenic lesion, TF-dependent FVIII activation sets the threshold for thrombus formation through contact phase-generated FIXa. In vitro, FXa stably associated with TF-FVIIa activates FVIII, but not FV. Moreover, nascent FXa product of TF-FVIIa can transiently escape the slow kinetics of Kunitz-type inhibition by TF pathway inhibitor and preferentially activates FVIII over FV. Thus, TF synergistically primes FIXa-dependent thrombin generation independently of cofactor activation by thrombin. Accordingly, FVIIa mutants deficient in direct TF-dependent thrombin generation, but preserving FVIIIa generation by nascent FXa, can support intrinsic pathway coagulation. In ex vivo flowing blood, a TF-FVIIa mutant complex with impaired free FXa generation but activating both FVIII and FIX supports efficient FVIII-dependent thrombus formation. Thus, a previously unrecognized TF-initiated pathway directly yielding FVIIIa-FIXa intrinsic tenase complex may be prohemostatic before further coagulation amplification by thrombin-dependent feedback loops enhances the risk of thrombosis.
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Aissaoui H, Prévost C, Boucharaba A, Sanhadji K, Bordet JC, Négrier C, Boukerche H. MDA-9/syntenin is essential for factor VIIa-induced signaling, migration, and metastasis in melanoma cells. J Biol Chem 2014; 290:3333-48. [PMID: 25505176 DOI: 10.1074/jbc.m114.606913] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Melanoma differentiation associated gene-9 (MDA-9), also known as syntenin, is a novel gene that positively regulates cancer cell motility, invasion, and metastasis through distinct biochemical and signaling pathways, but how MDA-9/syntenin is regulated in response to signals with the extracellular environment and promotes tumor progression is unclear. We now demonstrate that MDA-9/syntenin is dramatically up-regulated by a combination of rFVIIa and factor F(X) in malignant melanoma. Induction of MDA-9/syntenin in melanoma was found to occur in a thrombin-independent signaling pathway and involves the PAR-1/c-Src/Rho GTPases Rac1 and Cdc42/c-Jun N-terminal kinase axis resulting in the activation of paxillin, NF-κB, and matrix metalloproteinase-2 (MMP-2). MDA-9/syntenin physically interacts with c-Src through its PDZ binding motif following stimulation of melanoma cells with rFVIIa and FX. We also document that induction of this signaling pathway is required for TF·FVIIa·Xa-induced cell migration, invasion, and metastasis by melanoma cells. The present finding uncovers a novel role of MDA-9/syntenin as an important TF·FVIIa·Xa/PAR-1-regulated gene that initiates a signaling circuit essential for cell motility and invasion of metastatic melanoma. In these contexts, targeting TF·FVIIa·Xa and its relevant downstream targets such as MDA-9/syntenin, may represent a novel therapeutic strategy to control the evolution of neoplastic cells.
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Affiliation(s)
- Hanaa Aissaoui
- From the EA 4174, Onco-Hematology Unit, University Claude Bernard, INSERM, Lyon 1, 69372 Lyon, France
| | - Célia Prévost
- From the EA 4174, Onco-Hematology Unit, University Claude Bernard, INSERM, Lyon 1, 69372 Lyon, France
| | - Ahmed Boucharaba
- the Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland, and
| | - Kamel Sanhadji
- the Transplantation and Clinical Immunology Department, Edouart Herriot Hospital, Lyon, France
| | - Jean-Claude Bordet
- From the EA 4174, Onco-Hematology Unit, University Claude Bernard, INSERM, Lyon 1, 69372 Lyon, France
| | - Claude Négrier
- From the EA 4174, Onco-Hematology Unit, University Claude Bernard, INSERM, Lyon 1, 69372 Lyon, France
| | - Habib Boukerche
- From the EA 4174, Onco-Hematology Unit, University Claude Bernard, INSERM, Lyon 1, 69372 Lyon, France,
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7
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Wakabayashi H, Wintermute JM, Fay PJ. Combining mutations that modulate inter-subunit interactions and proteolytic inactivation enhance the stability of factor VIIIa. Thromb Haemost 2014; 112:43-52. [PMID: 24599523 DOI: 10.1160/th13-10-0918] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 01/17/2014] [Indexed: 11/05/2022]
Abstract
FVIIIa is labile due to the dissociation of A2 subunit. Previously, we introduced hydrophobic mutations at select A1/A2/A3 subunit interfaces yielding more stable FVIII(a) variants. Separately we showed that altering the sequence flanking the primary FXa cleavage site in FVIIIa (Arg336) yielded reduced rates of proteolytic inactivation of FVIIIa. In this study we prepared the FXa-cleavage resistant mutant (336(P4-P3')562) combined with mutations of Ala108Ile, Asp519Val/Glu665Val or Ala108Ile/Asp519Val/Glu665Val and examined the effects of these combinations relative to FVIII thermal stability, rates of FVIIIa decay and proteolytic inactivation of FVIIIa by FXa. Thermal decay rates for 336(P4-P3')562/Ala108Ile, 336(P4-P3')562/Asp519Val/Glu665Val, and 336(P4-P3')562/Ala108Ile/Asp519Val/Glu665Val variants were reduced by ~2- to 5-fold as compared with wild-type (WT) primarily reflecting the effects of the A domain interface mutations. FVIIIa decay rates for 336(P4-P3')562/Asp519Val/Glu665Val and 336(P4-P3')562/Ala108Ile/Asp519Val/Glu665Val variants were reduced by ~25 fold, indicating greater stability than the control Asp519Val/Glu665Val variant (~14-fold). Interestingly, 336(P4-P3')562/Asp519Val/Glu665Val and 336(P4-P3')562/Ala108Ile/Asp519Val/Glu665Val variants showed reduced FXa-inactivation rates compared with the 336(P4-P3')562 control (~4-fold), suggesting A2 subunit destabilisation is a component of proteolytic inactivation. Thrombin generation assays using the combination variants were similar to the Asp519Val/Glu665Val control. These results indicate that combining multiple gain-of-function FVIII mutations yields FVIII variants with increased stability relative to a single type of mutation.
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Affiliation(s)
| | | | - P J Fay
- Philip J. Fay, P.O. Box 712, Department of Biochemistry and Biophysics, 601 Elmwood Ave., Rochester, NY 14642, USA, Tel.: +1 585 275 6576, Fax: +1 585 275 6007, E-mail:
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8
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Wakabayashi H, Wintermute JM, Fay PJ. Combining mutations that modulate inter-subunit interactions and proteolytic inactivation enhance the stability of factor VIIIa. Thromb Haemost 2014. [DOI: 10.1160/th13-10-0887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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9
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Griffiths AE, Wintermute J, Newell-Caito JL, Fay PJ. Residues flanking scissile bonds in Factor VIII modulate rates of cleavage and proteolytic activation catalyzed by Factor Xa. Biochemistry 2013; 52:8060-8. [PMID: 24128092 DOI: 10.1021/bi4010123] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Factor Xa (FXa) proteolytically activates Factor VIII (FVIII) by cleaving P1 residues Arg(372), Arg(740), and Arg(1689). The Arg(372) site represents the rate-limiting step for procofactor activation, whereas cleavage at Arg(740) is a fast step. FXa also catalyzes inactivating cleavages that occur on a slower time scale than the activating ones. To assess the role of sequences flanking the Arg(372) and Arg(740) sites, recombinant FVIII variants in which P3-P3' sequences were swapped individually or in combination were prepared. Replacing the Arg(372) flanking sequence with that from the Arg(740) site increased the rate of cleavage at Arg(372), as judged by the ~5-fold increased rate in A1 subunit generation, and reduced the FVIIIa-dependent lag time for in situ FXa generation. The reciprocal swap yielded a nearly 2-fold increase in the rate of Arg(372) cleavage, while the combined double-swap variant showed a 10-fold rate increase at that site, consistent with the individual effects being additive. Although this cleavage represents the slow step for activation, the rate of this reaction appeared to be ~9-fold greater than the rate of the primary inactivating cleavage at Arg(336) in generating the A1(336) product. Interestingly, replacement of the Arg(372) flanking sequence with the Arg(740) sequence combined with an Arg(740)Gln mutation yielded both more rapid cleavage of the Arg(372) site and accelerated inactivating cleavages within the A1 subunit. These results indicate that flanking sequences in part modulate the reaction rates required for procofactor activation and influence the capacity of FXa as an initial activator of FVIII rather than an inactivator.
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Affiliation(s)
- Amy E Griffiths
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine , 601 Elmwood Avenue, Rochester, New York 14642, United States
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Griffiths AE, Rydkin I, Fay PJ. Factor VIIIa A2 subunit shows a high affinity interaction with factor IXa: contribution of A2 subunit residues 707-714 to the interaction with factor IXa. J Biol Chem 2013; 288:15057-64. [PMID: 23580639 DOI: 10.1074/jbc.m113.456467] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Factor (F) VIIIa forms a number of contacts with FIXa in assembling the FXase enzyme complex. Surface plasmon resonance was used to examine the interaction between immobilized biotinylated active site-modified FIXa, and FVIII and FVIIIa subunits. The FVIIIa A2 subunit bound FIXa with high affinity (Kd = 3.9 ± 1.6 nm) that was similar to the A3C1C2 subunit (Kd = 3.6 ± 0.6 nm). This approach was used to evaluate a series of baculovirus-expressed, isolated A2 domain (bA2) variants where alanine substitutions were made for individual residues within the sequence 707-714, the C-terminal region of A2 thought to be FIXa interactive. Three of six bA2 variants examined displayed 2- to 4-fold decreased affinity for FIXa as compared with WT bA2. The variant bA2 proteins were also tested in two reconstitution systems to determine activity and affinity parameters in forming FXase and FVIIIa. Vmax values for all variants were similar to the WT values, indicating that these residues do not affect cofactor function. All variants showed substantially greater increases in apparent Kd relative to WT in reconstituting the FXase complex (8- to 26-fold) compared with reconstituting FVIIIa (1.3- to 6-fold) suggesting that the mutations altered interaction with FIXa. bA2 domain variants with Ala replacing Lys(707), Asp(712), and Lys(713) demonstrated the greatest increases in apparent Kd (17- to 26-fold). These results indicate a high affinity interaction between the FVIIIa A2 subunit and FIXa and show a contribution of several residues within the 707-714 sequence to this binding.
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Affiliation(s)
- Amy E Griffiths
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine, Rochester, New York 14642, USA
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11
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Takeyama M, Wintermute JM, Manithody C, Rezaie AR, Fay PJ. Variable contributions of basic residues forming an APC exosite in the binding and inactivation of factor VIIIa. Biochemistry 2013; 52:2228-35. [PMID: 23480827 DOI: 10.1021/bi301632g] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Basic residues contained in the 39-, 60-, and 70-80-loops of activated protein C (APC) comprise an exosite that contributes to the binding and subsequent proteolytic inactivation of factor (F) VIIIa. Surface plasmon resonance (SPR) showed that WT APC bound to FVIII light chain (LC) and the FVIIIa A1/A3C1C2 dimer with equivalent affinity (Kd = 525 and 546 nM, respectively). These affinity values may reflect binding interactions to the acidic residue-rich a1 and a3 segments adjacent to A1 domain in the A1/A3C1C2 and A3 domain in LC, respectively. Results from SPR, using a panel of APC exosite variants where basic residues were mutated, in binding to immobilized FVIIIa A1/A3C1C2 or LC indicated ~4-10-fold increases in the Kd values relative to WT for several of the variants including Lys39Ala, Lys37-Lys38-Lys39/Pro-Gln-Glu, and Arg67Ala. On the other hand, a number of APC variants including Lys38Ala, Lys62Ala, and Lys78Ala showed little if any change in binding affinity to the FVIII substrates. FXa generation assays and Western blotting, used to monitor rates of FVIIIa inactivation and proteolysis at the primary cleavage site in the cofactor (Arg(336)), respectively, showed marked rate reductions relative to WT for the Lys39Ala, Lys37-Lys38-Lys39/Pro-Gln-Glu, Arg67Ala, and Arg74Ala variants. Furthermore, kinetic analysis monitoring FVIIIa inactivation by APC variants at varying FVIIIa substrate concentration showed ~2.6-4.4-fold increases in Km values relative to WT. These results show a variable contribution of basic residues comprising the APC exosite, with significant contributions from Lys39, Arg67, and Arg74 to forming a FVIIIa-interactive site.
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Affiliation(s)
- Masahiro Takeyama
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
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12
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Takeyama M, Wakabayashi H, Fay PJ. Contribution of factor VIII light-chain residues 2007-2016 to an activated protein C-interactive site. Thromb Haemost 2012; 109:187-98. [PMID: 23224054 DOI: 10.1160/th12-08-0561] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Accepted: 10/22/2012] [Indexed: 11/05/2022]
Abstract
Although factor (F) VIIIa is inactivated by activated protein C (APC) through cleavages in the FVIII heavy chain-derived A1 (Arg(336)) and A2 subunits (Arg(562), the FVIII light chain (LC) contributes to catalysis by binding the enzyme. ELISA-based binding assays showed that FVIII and FVIII LC bound to immobilised active site-modified APC (DEGR-APC) (apparent K(d) ~270 nM and 1.0 μM, respectively). Fluid-phase binding studies using fluorescence indicated an estimated K(d) of ~590 nM for acrylodan-labelled LC binding to DEGR-APC. Furthermore, FVIII LC effectively competed with FVIIIa in blocking APC-catalysed cleavage at Arg(336) (K(i) = 709 nM). A binding site previously identified near the C-terminal end of the A3 domain (residues 2007-2016) of FVIII LC was subjected to Ala-scanning mutagenesis. FXa generation assays and western and dot blotting were employed to assess the contribution of these residues to FVIIIa interactions with APC. Virtually all variants tested showed reductions in the rates of APC-catalysed inactivation of the cofactor and cleavage at the primary inactivation site (Arg(336)), with maximal reductions in inactivation rates (~3-fold relative to WT) and cleavage rates (~3 to ~9-fold relative to WT) observed for the Met2010Ala, Ser2011Ala, and Leu2013Ala variants. Titration of FVIIIa substrate concentration monitoring cleavage by a dot blot assay indicated that these variants also showed ~3-fold increases relative to WT while a double mutant (Met2010Ala/Ser2011Ala) showed a >4-fold increase in K(m). These results show a contribution of a number of residues within the 2007-2016 sequence, and in particular residues Met2010, Ser2011, and Leu2013 to an APC-interactive site.
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Affiliation(s)
- Masahiro Takeyama
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642, USA
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13
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DeAngelis JP, Wakabayashi H, Fay PJ. Sequences flanking Arg336 in factor VIIIa modulate factor Xa-catalyzed cleavage rates at this site and cofactor function. J Biol Chem 2012; 287:15409-17. [PMID: 22411993 DOI: 10.1074/jbc.m111.333948] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Factor (F)VIII can be activated to FVIIIa by FXa following cleavages at Arg(372), Arg(740), and Arg(1689). FXa also cleaves FVIII/FVIIIa at Arg(336) and Arg(562) resulting in inactivation of the cofactor. These inactivating cleavages occur on a slower time scale than the activating ones. We assessed the contributions to cleavage rate and cofactor function of residues flanking Arg(336), the primary site yielding FVIII(a) inactivation, following replacement of these residues with those flanking the faster-reacting Arg(740) and Arg(372) sites and the slower-reacting Arg(562) site. Replacing P4-P3' residues flanking Arg(336) with those from Arg(372) or Arg(740) resulted in ∼4-6-fold increases in rates of FXa-catalyzed inactivation of FVIIIa, which paralleled the rates of proteolysis at Arg(336). Examination of partial sequence replacements showed a predominant contribution of prime residues flanking the scissile bonds to the enhanced rates. Conversely, replacement of this sequence with residues flanking the slow-reacting Arg(562) site yielded inactivation and cleavage rates that were ∼40% that of the WT values. The capacity for FXa to activate FVIII variants where cleavage at Arg(336) was accelerated due to flanking sequence replacement showed marked reductions in peak activity, whereas reducing the cleavage rate at this site enhanced peak activity. Furthermore, plasma-based thrombin generation assays employing the variants revealed significant reductions in multiple parameter values with acceleration of Arg(336) cleavage suggesting increased down-regulation of FXase. Overall, these results are consistent with a model of competition for activating and inactivating cleavages catalyzed by FXa that is modulated in large part by sequences flanking the scissile bonds.
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Affiliation(s)
- Jennifer P DeAngelis
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine, Rochester, New York 14642, USA
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14
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Newell-Caito JL, Griffiths AE, Fay PJ. P3-P3' residues flanking scissile bonds in factor VIII modulate rates of substrate cleavage and procofactor activation by thrombin. Biochemistry 2012; 51:3451-9. [PMID: 22455313 DOI: 10.1021/bi300070z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Thrombin-catalyzed activation of factor VIII (FVIII) occurs through proteolysis at three P1 Arg residues: Arg(372) and Arg(740) in the FVIII heavy chain and Arg(1689) in the FVIII light chain. Cleavage at the latter two sites is relatively fast compared with cleavage at Arg(372), which appears to be rate-limiting. Examination of the P3-P3' residues flanking each P1 site revealed that those sequences at Arg(740) and Arg(1689) are more optimal for thrombin cleavage than at Arg(372), suggesting these sequences may impact reaction rates. Recombinant FVIII variants were prepared with mutations swapping scissile bond flanking sequences in the heavy chain individually and in combination with a second swap or with a P1 point mutation. Rates of generation of A1 and A3-C1-C2 subunits were determined by Western blotting and correlated with rates of cleavage at Arg(372) and Arg(1689), respectively. Rates of thrombin cleavage at Arg(372) were increased ~10- and ~3-fold compared with that of wild-type FVIII when it was replaced with P3-P3' residues flanking Arg(740) and Arg(1689), respectively, and these values paralleled increased rates of A2 subunit generation and procofactor activation. Positioning of more optimal residues flanking Arg(372) abrogated the need for initial cleavage at Arg(740) to facilitate this step. These results show marked changes in cleavage rates correlate with the extent of cleavage-optimal residues flanking the scissile bond and modulate the mechanism for procofactor activation.
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Affiliation(s)
- Jennifer L Newell-Caito
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine, 601 Elmwood Avenue, Rochester, NY 14642, USA
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Plantier JL, Saboulard D, Pellequer JL, Négrier C, Delcourt M. Functional mapping of the A2 domain from human factor VIII. Thromb Haemost 2012; 107:315-27. [PMID: 22234396 DOI: 10.1160/th11-07-0492] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Accepted: 11/24/2011] [Indexed: 11/05/2022]
Abstract
Coagulation factor VIII (FVIII) is a multidomain glycoprotein in which the FVIII A2 domain is a key structural element. We aimed at identifying residues within FVIII A2 domain that are crucial for the maintenance of the cofactor function. A high number (n=206) of mutants were generated by substituting original residues with alanine. The mutants were expressed in COS-1 cells and their antigen levels and procoagulant activities were measured. The residues were classified in three categories: those with a non-detrimental alteration of their activities (activity >50 % of control FVIII; n=98), those with a moderate alteration (15 %<activity<50%; n=45) and those that were severely affected (activity<15%; n=63). The mutants sensitive to mutation were retrieved in the HAMSTeRS database with a higher percentage than those that were not affected (58.8% vs. 9.2%). The results revealed the existence of clusters of residues that are sensitive (Arg418-Phe436, Thr459-Ile475, Ser535-Gly549, Asn618-Ala635) or not (Leu398-Arg418, Pro485-Asp500, Gly506-Gly520, Pro596-Asp605) to mutations. The stretches of residues sensitive to mutations were buried within the molecule suggesting that these amino acids participate in the maintenance of the A2 domain structure. In contrast, residues resistant to mutations formed external loops without well- defined structures suggesting that these loops were not crucial for the process of factor X activation. This study provided a detailed map of the FVIII A2 domain between residues 371 and 649, identifying residues crucial for maintaining FVIII function and residues that can be mutated without jeopardising the coagulant activity.
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Affiliation(s)
- Jean-Luc Plantier
- Laboratoire d’Hémobiologie EA4174-IFR62 Faculté de Médecine RTH Laennec, Université de Lyon, Lyon, France.
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Gupta M, Lillicrap D, Stain AM, Friedman KD, Carcao MD. Therapeutic consequences for misdiagnosis of type 2N von Willebrand disease. Pediatr Blood Cancer 2011; 57:1081-3. [PMID: 21425451 DOI: 10.1002/pbc.23120] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Accepted: 02/14/2011] [Indexed: 11/06/2022]
Abstract
Patients presenting with a low FVIII:C and with normal VWF levels are usually presumed to have hemophilia (males) or be carriers for hemophilia (females). Some of these patients may instead have VWD:2N. Such patients if misdiagnosed are likely to suffer from insufficiently treated bleeds. We report 2 males and 1 female who presented with a low FVIII:C (1-21%) and minimally reduced/normal VWF and were assumed to have, or be a carrier for, hemophilia A. Eventually all were found to have VWD:2N. Prior to the correct diagnosis the males had been treated with rFVIII with poor responses and ultimately adverse clinical consequences.
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Affiliation(s)
- Madhu Gupta
- Division of Hematology/Oncology, Hospital for Sick Children, Toronto, Ontario, Canada
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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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