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Wilson HP, Pierre A, Paysse AL, Kumar N, Cooley BC, Rudra P, Dorsey AW, Polania-Villanueva D, Chatterjee S, Janbain M, Velez MC, Majumder R. Protein S antibody as an adjunct therapy for hemophilia B. Blood Adv 2024; 8:441-452. [PMID: 37773781 PMCID: PMC10827407 DOI: 10.1182/bloodadvances.2023010819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 09/19/2023] [Accepted: 09/19/2023] [Indexed: 10/01/2023] Open
Abstract
ABSTRACT Hemophilia B (HB) is caused by an inherited deficiency of plasma coagulation factor IX (FIX). Approximately 60% of pediatric patients with HB possess a severe form of FIX deficiency (<1% FIX activity). Treatment typically requires replacement therapy through the administration of FIX. However, exogenous FIX has a limited functional half-life, and the natural anticoagulant protein S (PS) inhibits activated FIX (FIXa). PS ultimately limits thrombin formation, which limits plasma coagulation. This regulation of FIXa activity by PS led us to test whether inhibiting PS would extend the functional half-life of FIX and thereby prolong FIX-based HB therapy. We assayed clotting times and thrombin generation to measure the efficacy of a PS antibody for increasing FIX activity in commercially obtained plasma and plasma from pediatric patients with HB. We included 11 pediatric patients who lacked additional comorbidities and coagulopathies. In vivo, we assessed thrombus formation in HB mice in the presence of the FIXa ± PS antibody. We found an accelerated rate of clotting in the presence of PS antibody. Similarly, the peak thrombin formed was significantly greater in the presence of the PS antibody, even in plasma from patients with severe HB. Furthermore, HB mice injected with PS antibody and FIX had a 4.5-fold higher accumulation of fibrin at the thrombus induction site compared with mice injected with FIX alone. Our findings imply that a PS antibody would be a valuable adjunct to increase the effectiveness of FIX replacement therapy in pediatric patients who have mild, moderate, and severe HB.
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Affiliation(s)
- Hope P. Wilson
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, New Orleans, LA
- Department of Pediatric Hematology and Oncology, University of Alabama at Birmingham, Birmingham, AL
| | - Aliyah Pierre
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, New Orleans, LA
| | - Ashley L. Paysse
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, New Orleans, LA
| | - Narender Kumar
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, New Orleans, LA
| | - Brian C. Cooley
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC
| | | | - Adrianne W. Dorsey
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, New Orleans, LA
| | - Diana Polania-Villanueva
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, New Orleans, LA
| | - Sabyasachi Chatterjee
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, New Orleans, LA
| | - Maissaa Janbain
- Department of Hematology & Medical Oncology, Tulane University, New Orleans, LA
| | - Maria C. Velez
- Department of Pediatric Hematology and Oncology, Children's Hospital of New Orleans, New Orleans, LA
| | - Rinku Majumder
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, New Orleans, LA
- Department of Interdisciplinary Oncology, Louisiana State University Health Sciences Center, New Orleans, LA
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2
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Strijbis VJF, Vatandoost J, Bos MHA. Crippling down factor IX for therapeutic gain. J Thromb Haemost 2023; 21:3287-3291. [PMID: 37678545 DOI: 10.1016/j.jtha.2023.08.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 08/29/2023] [Accepted: 08/29/2023] [Indexed: 09/09/2023]
Affiliation(s)
- Viola J F Strijbis
- Department of Internal Medicine, Division of Thrombosis and Hemostasis, Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, Leiden, The Netherlands. https://twitter.com/ViolaStrijbis
| | - Jafar Vatandoost
- Department of Biology, Hakim Sabzevari University, Sabzevar, Iran
| | - Mettine H A Bos
- Department of Internal Medicine, Division of Thrombosis and Hemostasis, Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, Leiden, The Netherlands.
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3
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Nguyen GN, Lindgren JR, Seleme MC, Kafle S, Zander CB, Zheng XL, Sabatino DE. Altered cleavage of human factor VIII at the B-domain and acidic region 3 interface enhances expression after gene therapy in hemophilia A mice. J Thromb Haemost 2023; 21:2101-2113. [PMID: 37080538 PMCID: PMC11157168 DOI: 10.1016/j.jtha.2023.04.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 03/17/2023] [Accepted: 04/04/2023] [Indexed: 04/22/2023]
Abstract
BACKGROUND Variants of human factor VIII (hFVIII) have been developed to further understand the structure and function of hFVIII and improve gene-based therapeutics. We have previously characterized several hFVIII variants of the furin cleavage site (1645-1648) with improved secretion. We have also identified a second cleavage site in the acidic region 3 (a3) (1657-1658) that becomes the primary hFVIII intracellular cleavage position in the absence of the furin site. We tested a hypothesis that modification of this site may confer additional functional advantages to hFVIII. OBJECTIVES The aim of this study was to conduct the biochemical and functional characterization of hFVIII variants of the furin cleavage site, the a3 cleavage site, or in combination, both in vitro and in vivo after AAV mediated gene therapy. METHODS Recombinant hFVIII variants of the furin cleavage site (hFVIII-Δ3), the a3 cleavage site (hFVIII-S1657P/D1658E [SP/DE]), or in combination (hFVIII-Δ3-SP/DE) were purified and characterized in vitro and in vivo. RESULTS Recombinant hFVIII-Δ3, hFVIII-SP/DE, and hFVIII-Δ3-SP/DE variants all had comparable specific activity to B-domain deleted (BDD) hFVIII. Hemophilia A mice tolerant to hFVIII did not develop immune responses to hFVIII after protein challenge with these variants or after adeno-associated virus (AAV) delivery. Following AAV delivery, hFVIII-Δ3-SP/DE resulted in expression levels that were 2- to 5-fold higher than those with hFVIII-BDD in hemophilia A mice. CONCLUSION The novel hFVIII-Δ3-SP/DE variant of the furin and a3 cleavage sites significantly improved secretion compared with hFVIII-BDD. This key feature of the Δ3-SP/DE variant provides a unique strategy that can be combined with other approaches to further improve factor VIII expression to achieve superior efficacy in AAV-based gene therapy for hemophilia A.
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Affiliation(s)
- Giang N Nguyen
- The Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Jonathan R Lindgren
- The Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Maria C Seleme
- The Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Samita Kafle
- The Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Catherine B Zander
- Department of Pathology, University of Alabama at Birmingham School of Medicine, University of Alabama, Birmingham, Alabama, USA
| | - X Long Zheng
- Department of Pathology and Laboratory Medicine, The University of Kansas Medical Center, Kansas City, Kansas, USA; Institute of Reproductive Medicine and Developmental Science, The University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Denise E Sabatino
- The Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA; Department of Pediatrics, Division of Hematology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
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4
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Ivanciu L, Arruda VR, Camire RM. Factor IXa variants resistant to plasma inhibitors enhance clot formation in vivo. Blood 2023; 141:2022-2032. [PMID: 36724452 PMCID: PMC10163311 DOI: 10.1182/blood.2022018083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 12/28/2022] [Accepted: 01/13/2023] [Indexed: 02/03/2023] Open
Abstract
Factor IXa (FIXa) plays a pivotal role in coagulation by contributing to FX activation via the intrinsic pathway. Although antithrombin (AT) and other plasma inhibitors are thought to regulate FIXa procoagulant function, the impact of FIXa inhibition on thrombin generation and clot formation in vivo remains unclear. Here, we generated FIXa variants with altered reactivity to plasma inhibitors that target the FIXa active site but maintain procoagulant function when bound to its cofactor, FVIIIa. We found that selected FIXa variants (eg, FIXa-V16L) have a prolonged activity half-life in the plasma due, in part, to AT resistance. Studies using hemophilia B mice have shown that delayed FIXa inhibition has a major impact on reducing the bleeding phenotype and promoting thrombus formation following administration of FIX protein. Overall, these results demonstrate that the regulation of FIXa inhibition contributes in a major way to the spatial and temporal control of coagulation at the site of vascular injury. Our findings provide novel insights into the physiological regulation of FIXa, enhance our understanding of thrombus formation in vivo via the intrinsic pathway, and suggest that altering FIXa inhibition could have therapeutic benefits.
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Affiliation(s)
- Lacramioara Ivanciu
- Division of Hematology and the Raymond G. Perelman Center for Cellular and Molecular Therapeutics, Children’s Hospital of Philadelphia, Philadelphia, PA
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Valder R. Arruda
- Division of Hematology and the Raymond G. Perelman Center for Cellular and Molecular Therapeutics, Children’s Hospital of Philadelphia, Philadelphia, PA
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Rodney M. Camire
- Division of Hematology and the Raymond G. Perelman Center for Cellular and Molecular Therapeutics, Children’s Hospital of Philadelphia, Philadelphia, PA
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
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5
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Liu W, Xue F, Fu R, Ding B, Li M, Sun T, Chen Y, Liu X, Ju M, Dai X, Wu Q, Zhou Z, Yu J, Wang X, Zhu Q, Zhou H, Yang R, Zhang L. Preclinical studies of a factor X activator and a phase 1 trial for hemophilia patients with inhibitors. J Thromb Haemost 2023; 21:1453-1465. [PMID: 36796484 DOI: 10.1016/j.jtha.2023.01.040] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 01/10/2023] [Accepted: 01/30/2023] [Indexed: 02/16/2023]
Abstract
BACKGROUND Bleeding episodes in hemophiliacs with inhibitors are difficult to control. Staidson protein-0601 (STSP-0601), a specific factor (F)X activator purified from the venom of Daboia russelii siamensis, has been developed. OBJECTIVES We aimed to investigate the efficacy and safety of STSP-0601 in preclinical and clinical studies. METHODS In vitro and in vivo preclinical studies were performed. A phase 1, first-in-human, multicenter, and open-label trial was conducted. The clinical study was divided into parts A and B. Hemophiliacs with inhibitors were eligible for this study. Patients received a single intravenous injection of STSP-0601 (0.01 U/kg, 0.04 U/kg, 0.08 U/kg, 0.16 U/kg, 0.32 U/kg, or 0.48 U/kg) in part A or a maximum of 6 4-hourly injections (0.16 U/kg) in part B. The primary endpoint for each part was the number of adverse events (AEs) from baseline to 168 hours after administration. This study was registered at clinicaltrials.gov (NCT-04747964 and NCT-05027230). RESULTS Preclinical studies showed that STSP-0601 could specifically activate FX in a dose-dependent manner. In the clinical study, 16 patients in part A and 7 patients in part B were enrolled. Eight (22.2%) AEs in part A and 18 (75.0%) AEs in part B were reported to be related to STSP-0601. Neither severe AEs nor dose-limiting toxicity events were reported. There were no thromboembolic event. The antidrug antibody of STSP-0601 was not detected. CONCLUSION Preclinical and clinical studies showed that STSP-0601 had a good ability to activate FX and had a good safety profile. STSP-0601 could be used as a hemostatic treatment in hemophiliacs with inhibitors.
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Affiliation(s)
- Wei Liu
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin Key Laboratory of Gene Therapy for Blood Diseases, Chinese Academy of Medical Sciences Key Laboratory of Gene Therapy for Blood Diseases, Tianjin, China
| | - Feng Xue
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin Key Laboratory of Gene Therapy for Blood Diseases, Chinese Academy of Medical Sciences Key Laboratory of Gene Therapy for Blood Diseases, Tianjin, China
| | - Rongfeng Fu
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin Key Laboratory of Gene Therapy for Blood Diseases, Chinese Academy of Medical Sciences Key Laboratory of Gene Therapy for Blood Diseases, Tianjin, China
| | - Bingjie Ding
- Department of Hematology, The Affiliated Cancer Hospital of Zhengzhou University & Henan Cancer Hospital, Hemostasis and Thrombosis Diagnostic Engineering Research Center of Henan Province, Zhengzhou, China
| | - Mengjuan Li
- Department of Hematology, The Affiliated Cancer Hospital of Zhengzhou University & Henan Cancer Hospital, Hemostasis and Thrombosis Diagnostic Engineering Research Center of Henan Province, Zhengzhou, China
| | - Ting Sun
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin Key Laboratory of Gene Therapy for Blood Diseases, Chinese Academy of Medical Sciences Key Laboratory of Gene Therapy for Blood Diseases, Tianjin, China
| | - Yunfei Chen
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin Key Laboratory of Gene Therapy for Blood Diseases, Chinese Academy of Medical Sciences Key Laboratory of Gene Therapy for Blood Diseases, Tianjin, China
| | - Xiaofan Liu
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin Key Laboratory of Gene Therapy for Blood Diseases, Chinese Academy of Medical Sciences Key Laboratory of Gene Therapy for Blood Diseases, Tianjin, China
| | - Mankai Ju
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin Key Laboratory of Gene Therapy for Blood Diseases, Chinese Academy of Medical Sciences Key Laboratory of Gene Therapy for Blood Diseases, Tianjin, China
| | - Xinyue Dai
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin Key Laboratory of Gene Therapy for Blood Diseases, Chinese Academy of Medical Sciences Key Laboratory of Gene Therapy for Blood Diseases, Tianjin, China
| | - Quanrui Wu
- Staidson (Beijing) Biopharmaceuticals Co, Ltd, Beijing, China
| | - Zan Zhou
- Staidson (Beijing) Biopharmaceuticals Co, Ltd, Beijing, China
| | - Jiaojiao Yu
- Staidson (Beijing) Biopharmaceuticals Co, Ltd, Beijing, China
| | - Xiaomin Wang
- Staidson (Beijing) Biopharmaceuticals Co, Ltd, Beijing, China
| | - Qing Zhu
- Staidson (Beijing) Biopharmaceuticals Co, Ltd, Beijing, China
| | - Hu Zhou
- Department of Hematology, The Affiliated Cancer Hospital of Zhengzhou University & Henan Cancer Hospital, Hemostasis and Thrombosis Diagnostic Engineering Research Center of Henan Province, Zhengzhou, China.
| | - Renchi Yang
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin Key Laboratory of Gene Therapy for Blood Diseases, Chinese Academy of Medical Sciences Key Laboratory of Gene Therapy for Blood Diseases, Tianjin, China.
| | - Lei Zhang
- State Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin Key Laboratory of Gene Therapy for Blood Diseases, Chinese Academy of Medical Sciences Key Laboratory of Gene Therapy for Blood Diseases, Tianjin, China.
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6
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Zimowski KL, Petrillo T, Ho MD, Wechsler J, Shields JE, Denning G, Jhita N, Rivera AA, Escobar MA, Kempton CL, Camire RM, Doering CB. F5-Atlanta: A novel mutation in F5 associated with enhanced East Texas splicing and FV-short production. J Thromb Haemost 2021; 19:1653-1665. [PMID: 33773040 DOI: 10.1111/jth.15314] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 03/21/2021] [Accepted: 03/22/2021] [Indexed: 01/14/2023]
Abstract
BACKGROUND Elucidating the molecular pathogenesis underlying East Texas bleeding disorder (ET) led to the discovery of alternatively spliced F5 transcripts harboring large deletions within exon 13. These alternatively spliced transcripts produce a shortened form of coagulation factor V (FV) in which a large portion of its B-domain is deleted. These FV isoforms bind tissue factor pathway inhibitor alpha (TFPIα) with high affinity, prolonging its circulatory half-life and enhancing its anticoagulant effects. While two missense pathogenic variants highlighted this alternative splicing event, similar internally deleted FV proteins are found in healthy controls. OBJECTIVE We identified a novel heterozygous 832 base pair deletion within F5 exon 13, termed F5-Atlanta (F5-ATL), in a patient with severe bleeding. Our objective is to investigate the effect of this deletion on F5 and FV expression. METHODS & RESULTS Assessment of patient plasma revealed markedly elevated levels of total and free TFPI and a FV isoform similar in size to the FV-short described in ET. Sequencing analyses of cDNA revealed the presence of a transcript alternatively spliced using the ET splice sites, thereby removing the F5-ATL deletion. This alternative splicing pattern was recapitulated by heterologous expression in mammalian cells. CONCLUSIONS These findings support a mechanistic model consisting of cis-acting regulatory sequences encoded within F5 exon 13 that control alternative splicing at the ET splice sites and thereby regulate circulating FV-short and TFPIα levels.
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Affiliation(s)
- Karen L Zimowski
- Aflac Cancer and Blood Disorders Center, Emory University/Children's Healthcare of Atlanta, Atlanta, Georgia, USA
| | - Teodolinda Petrillo
- The Children's Hospital of Philadelphia, The Raymond G. Perelman Center for Cellular and Molecular Therapeutics, Philadelphia, Pennsylvania, USA
| | - Michelle D Ho
- The Children's Hospital of Philadelphia, The Raymond G. Perelman Center for Cellular and Molecular Therapeutics, Philadelphia, Pennsylvania, USA
| | - Julie Wechsler
- Aflac Cancer and Blood Disorders Center, Emory University/Children's Healthcare of Atlanta, Atlanta, Georgia, USA
| | - Jordan E Shields
- Aflac Cancer and Blood Disorders Center, Emory University/Children's Healthcare of Atlanta, Atlanta, Georgia, USA
| | | | | | | | - Miguel A Escobar
- University of Texas Houston Health Science Center, Houston, Texas, USA
| | - Christine L Kempton
- Department of Hematology and Medical Oncology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Rodney M Camire
- The Children's Hospital of Philadelphia, The Raymond G. Perelman Center for Cellular and Molecular Therapeutics, Philadelphia, Pennsylvania, USA
- Division of Hematology, Department of Pediatrics, Perelman School of Medicine, The University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Christopher B Doering
- Aflac Cancer and Blood Disorders Center, Emory University/Children's Healthcare of Atlanta, Atlanta, Georgia, USA
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7
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Hafer A, McCann L. Direct oral anticoagulant reversal: An update. Nursing 2021; 51:54-64. [PMID: 34014879 DOI: 10.1097/01.nurse.0000743104.69943.67] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
ABSTRACT The rise in direct oral anticoagulant (DOAC) use means nurses must understand the reversal of these agents in case of bleeding. Depending on bleed severity, as well as other criteria, pharmacologic reversal can be considered in place of supportive care alone. Knowledge of literature surrounding DOAC reversal is crucial.
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Affiliation(s)
- Andrea Hafer
- Andrea Hafer is a critical care clinical pharmacist at Riddle Hospital in Media, Pa., and Lindsay McCann is a critical care clinical pharmacy specialist at Bryn Mawr Hospital in Bryn Mawr, Pa
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8
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Adili R, Jackson M, Stanger L, Dai X, Li M, Li BX, Holinstat M. Slounase, a Batroxobin Containing Activated Factor X Effectively Enhances Hemostatic Clot Formation and Reducing Bleeding in Hypocoagulant Conditions in Mice. Clin Appl Thromb Hemost 2021; 27:10760296211018510. [PMID: 34047195 PMCID: PMC8165871 DOI: 10.1177/10760296211018510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Uncontrolled bleeding associated with trauma and surgery is the leading
cause of preventable death. Batroxobin, a snake venom-derived
thrombin-like serine protease, has been shown to clot fibrinogen by
cleaving fibrinopeptide A in a manner distinctly different from
thrombin, even in the presence of heparin. The biochemical properties
of batroxobin and its effect on coagulation have been well
characterized in vitro. However, the efficacy of
batroxobin on hemostatic clot formation in vivo is
not well studied due to the lack of reliable in vivo
hemostasis models. Here, we studied the efficacy of batroxobin and
slounase, a batroxobin containing activated factor X, on hemostatic
clot composition and bleeding using intravital microcopy laser
ablation hemostasis models in micro and macro vessels and liver
puncture hemostasis models in normal and heparin-induced hypocoagulant
mice. We found that prophylactic treatment in wild-type mice with
batroxobin, slounase and activated factor X significantly enhanced
platelet-rich fibrin clot formation following vascular injury. In
heparin-treated mice, batroxobin treatment resulted in detectable
fibrin formation and a modest increase in hemostatic clot size, while
activated factor X had no effect. In contrast, slounase treatment
significantly enhanced both platelet recruitment and fibrin formation,
forming a stable clot and shortening bleeding time and blood loss in
wild-type and heparin-treated hypocoagulant mice. Our data demonstrate
that, while batroxobin enhances fibrin formation, slounase was able to
enhance hemostasis in normal mice and restore hemostasis in
hypocoagulant conditions via the enhancement of fibrin formation and
platelet activation, indicating that slounase is more effective in
controlling hemorrhage.
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Affiliation(s)
- Reheman Adili
- Department of Pharmacology, 1259University of Michigan, Ann Arbor, MI, USA
| | - Madeline Jackson
- Department of Pharmacology, 1259University of Michigan, Ann Arbor, MI, USA
| | - Livia Stanger
- Department of Pharmacology, 1259University of Michigan, Ann Arbor, MI, USA
| | - Xiangrong Dai
- Zhaoke Pharmaceutical (Hefei) Co. Limited, Hefei, Anhui, China
| | - Mandy Li
- Lee's Pharmaceutical Holdings Limited. Shatin, Hong Kong, China
| | | | - Michael Holinstat
- Department of Pharmacology, 1259University of Michigan, Ann Arbor, MI, USA.,Department of Internal Medicine, Division of Cardiovascular Medicine, 1259University of Michigan, Ann Arbor, MI, USA
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9
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Activated protein C has a regulatory role in factor VIII function. Blood 2021; 137:2532-2543. [PMID: 33512448 DOI: 10.1182/blood.2020007562] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 12/17/2020] [Indexed: 11/20/2022] Open
Abstract
Mechanisms thought to regulate activated factor VIII (FVIIIa) cofactor function include A2-domain dissociation and activated protein C (APC) cleavage. Unlike A2-domain dissociation, there is no known phenotype associated with altered APC cleavage of FVIII, and biochemical studies have suggested APC plays a marginal role in FVIIIa regulation. However, the in vivo contribution of FVIIIa inactivation by APC is unexplored. Here we compared wild-type B-domainless FVIII (FVIII-WT) recombinant protein with an APC-resistant FVIII variant (FVIII-R336Q/R562Q; FVIII-QQ). FVIII-QQ demonstrated expected APC resistance without other changes in procoagulant function or A2-domain dissociation. In plasma-based studies, FVIII-WT/FVIIIa-WT demonstrated dose-dependent sensitivity to APC with or without protein S, whereas FVIII-QQ/FVIIIa-QQ did not. Importantly, FVIII-QQ demonstrated approximately fivefold increased procoagulant function relative to FVIII-WT in the tail clip and ferric chloride injury models in hemophilia A (HA) mice. To minimize the contribution of FV inactivation by APC in vivo, a tail clip assay was performed in homozygous HA/FV Leiden (FVL) mice infused with FVIII-QQ or FVIII-WT in the presence or absence of monoclonal antibody 1609, an antibody that blocks murine PC/APC hemostatic function. FVIII-QQ again demonstrated enhanced hemostatic function in HA/FVL mice; however, FVIII-QQ and FVIII-WT performed analogously in the presence of the PC/APC inhibitory antibody, indicating the increased hemostatic effect of FVIII-QQ was APC specific. Our data demonstrate APC contributes to the in vivo regulation of FVIIIa, which has the potential to be exploited to develop novel HA therapeutics.
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10
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Camire RM. Blood coagulation factor X: molecular biology, inherited disease, and engineered therapeutics. J Thromb Thrombolysis 2021; 52:383-390. [PMID: 33886037 DOI: 10.1007/s11239-021-02456-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/13/2021] [Indexed: 12/19/2022]
Abstract
Blood coagulation factor X/Xa sits at a pivotal point in the coagulation cascade and has a role in each of the three major pathways (intrinsic, extrinsic and the common pathway). Due to this central position, it is an attractive therapeutic target to either enhance or dampen thrombin generation. In this brief review, I will summarize key developments in the molecular understanding of this critical clotting factor and discuss the molecular basis of FX deficiency, highlight difficulties in expressing recombinant factor X, and detail two factor X variants evaluated clinically.
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Affiliation(s)
- Rodney M Camire
- Division of Hematology and the Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA. .,Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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11
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Petrillo T, Ayombil F, Van't Veer C, Camire RM. Regulation of factor V and factor V-short by TFPIα: Relationship between B-domain proteolysis and binding. J Biol Chem 2021; 296:100234. [PMID: 33376137 PMCID: PMC7948760 DOI: 10.1074/jbc.ra120.016341] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 12/17/2020] [Accepted: 12/29/2020] [Indexed: 12/25/2022] Open
Abstract
Coagulation factor V (FV) plays an anticoagulant role but serves as a procoagulant cofactor in the prothrombinase complex once activated to FVa. At the heart of these opposing effects is the proteolytic removal of its central B-domain, including conserved functional landmarks (basic region, BR; 963–1008 and acidic region 2, AR2; 1493–1537) that enforce the inactive FV procofactor state. Tissue factor pathway inhibitor α (TFPIα) has been associated with FV as well as FV-short, a physiologically relevant isoform with a shortened B-domain missing the BR. However, it is unclear which forms of FV are physiologic ligands for TFPIα. Here, we characterize the binding and regulation of FV and FV-short by TFPIα via its positively charged C-terminus (TFPIα-BR) and examine how bond cleavage in the B-domain influences these interactions. We show that FV-short is constitutively active and functions in prothrombinase like FVa. Unlike FVa, FV-short binds with high affinity (Kd ∼1 nM) to TFPIα-BR, which blocks procoagulant function unless FV-short is cleaved at Arg1545, removing AR2. Importantly, we do not observe FV binding (μM detection limit) to TFPIα. However, cleavage at Arg709 and Arg1018 displaces the FV BR, exposing AR2 and allowing TFPIα to bind via its BR. We conclude that for full-length FV, the detachment of FV BR from AR2 is necessary and sufficient for TFPIα binding and regulation. Our findings pinpoint key forms of FV, including FV-short, that act as physiologic ligands for TFPIα and establish a mechanistic framework for assessing the functional connection between these proteins.
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Affiliation(s)
- Teodolinda Petrillo
- Division of Hematology and the Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Francis Ayombil
- Division of Hematology and the Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Cornelis Van't Veer
- Center of Experimental and Molecular Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, the Netherlands
| | - Rodney M Camire
- Division of Hematology and the Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA; Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
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12
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Deguchi H, Morla S, Griffin JH. Novel blood coagulation molecules: Skeletal muscle myosin and cardiac myosin. J Thromb Haemost 2021; 19:7-19. [PMID: 32920971 PMCID: PMC7819347 DOI: 10.1111/jth.15097] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 09/03/2020] [Accepted: 09/03/2020] [Indexed: 12/21/2022]
Abstract
Essentials Striated muscle myosins can promote prothrombin activation by FXa or FVa inactivation by APC. Cardiac myosin and skeletal muscle myosin are pro-hemostatic in murine tail cut bleeding models. Infused cardiac myosin exacerbates myocardial injury caused by myocardial ischemia reperfusion. Skeletal muscle myosin isoforms that circulate in human plasma can be grouped into 3 phenotypes. ABSTRACT: Two striated muscle myosins, namely skeletal muscle myosin (SkM) and cardiac myosin (CM), may potentially contribute to physiologic mechanisms for regulation of thrombosis and hemostasis. Thrombin is generated from activation of prothrombin by the prothrombinase (IIase) complex comprising factor Xa, factor Va, and Ca++ ions located on surfaces where these factors are assembled. We discovered that SkM and CM, which are abundant motor proteins in skeletal and cardiac muscles, can provide a surface for thrombin generation by the prothrombinase complex without any apparent requirement for phosphatidylserine or lipids. These myosins can also provide a surface that supports the inactivation of factor Va by activated protein C/protein S, resulting in negative feedback downregulation of thrombin generation. Although the physiologic significance of these reactions remains to be established for humans, substantive insights may be gleaned from murine studies. In mice, exogenously infused SkM and CM can promote hemostasis as they are capable of reducing tail cut bleeding. In a murine myocardial ischemia-reperfusion injury model, exogenously infused CM exacerbates myocardial infarction damage. Studies of human plasmas show that SkM antigen isoforms of different MWs circulate in human plasma, and they can be used to identify three plasma SkM phenotypes. A pilot clinical study showed that one SkM isoform pattern appeared to be linked to isolated pulmonary embolism. These discoveries enable multiple preclinical and clinical studies of SkM and CM, which should provide novel mechanistic insights with potential translational relevance for the roles of CM and SkM in the pathobiology of hemostasis and thrombosis.
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Affiliation(s)
- Hiroshi Deguchi
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Shravan Morla
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - John H Griffin
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
- Division of Hematology, Department of Medicine, University of California, San Diego, CA, USA
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13
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Silva Blas Y, Diringer MN, Lo B, Masjuan J, Pérez de la Ossa N, Cardinal M, Yong F, Zhu T, Li G, Arkin S. Phase 1b Study to Evaluate Safety, Tolerability, and Maximum Tolerated Dose of PF-05230907 for Intracerebral Hemorrhage. Stroke 2020; 52:294-298. [PMID: 33272131 DOI: 10.1161/strokeaha.120.029789] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND AND PURPOSE This study aimed to determine the maximum tolerated dose and to evaluate the overall safety and tolerability of single doses of PF-05230907 in subjects with acute intracerebral hemorrhage. METHODS Individuals presenting with intracerebral hemorrhage were enrolled in a phase 1, multicenter, open-label clinical trial. A Bayesian modified continual reassessment method design based on treatment-emergent thromboembolic or ischemic events was adopted. Sequential dosing, an external data monitoring committee, and prespecified stopping rules were incorporated as safeguards. RESULTS Twenty-one subjects received PF-05230907. The mean (±SD) age in years and intracerebral hemorrhage volume in mL at baseline were 62 (±9) and 18 (±11), respectively. Two treatment-emergent thromboembolic or ischemic events occurred (deep vein thrombosis and cerebral ischemia), in the 30 μg/kg dose group. There were no other clear drug-related toxicities at dose levels ranging from 5 to 30 μg/kg. At the time of study termination, the maximum tolerated dose was estimated to be 24 μg/kg, with a mean fitted dose-toxicity estimate of 11.9% (95% CI, 1.2%-27.4%). CONCLUSIONS Single doses of PF-05230907 appeared to be tolerated across a range of doses in the intracerebral hemorrhage population, with thrombotic events observed only at the highest dose level tested. Recruitment within the recommended therapeutic window of opportunity remains a challenge. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02687191.
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Affiliation(s)
| | | | - Benjamin Lo
- Montreal Neurological Institute, Quebec, Canada (B.L.)
| | - Jaime Masjuan
- Hospital Universitario Ramón y Cajal, Madrid, Spain (J.M.)
| | | | | | | | - Tong Zhu
- Pfizer Inc, Cambridge, MA (M.C., F.Y., T.Z., S.A.)
| | - Gang Li
- Pfizer Inc, Collegeville, PA (G.L.)
| | - Steven Arkin
- Pfizer Inc, Cambridge, MA (M.C., F.Y., T.Z., S.A.)
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14
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Schreuder M, Poenou G, Strijbis VJF, Cheung KL, Reitsma PH, Bos MHA. Evolutionary Adaptations in Pseudonaja Textilis Venom Factor X Induce Zymogen Activity and Resistance to the Intrinsic Tenase Complex. Thromb Haemost 2020; 120:1512-1523. [PMID: 32820486 DOI: 10.1055/s-0040-1715441] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The venom of the Australian snake Pseudonaja textilis comprises powerful prothrombin activators consisting of factor X (v-ptFX)- and factor V-like proteins. While all vertebrate liver-expressed factor X (FX) homologs, including that of P. textilis, comprise an activation peptide of approximately 45 to 65 residues, the activation peptide of v-ptFX is significantly shortened to 27 residues. In this study, we demonstrate that exchanging the human FX activation peptide for the snake venom ortholog impedes proteolytic cleavage by the intrinsic factor VIIIa-factor IXa tenase complex. Furthermore, our findings indicate that the human FX activation peptide comprises an essential binding site for the intrinsic tenase complex. Conversely, incorporation of FX into the extrinsic tissue factor-factor VIIa tenase complex is completely dependent on exosite-mediated interactions. Remarkably, the shortened activation peptide allows for factor V-dependent prothrombin conversion while in the zymogen state. This indicates that the active site of FX molecules comprising the v-ptFX activation peptide partially matures upon assembly into a premature prothrombinase complex. Taken together, the shortened activation peptide is one of the remarkable characteristics of v-ptFX that has been modified from its original form, thereby transforming FX into a powerful procoagulant protein. Moreover, these results shed new light on the structural requirements for serine protease activation and indicate that catalytic activity can be obtained without formation of the characteristic Ile16-Asp194 salt bridge via modification of the activation peptide.
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Affiliation(s)
- Mark Schreuder
- Division of Thrombosis and Hemostasis, Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Geraldine Poenou
- Division of Thrombosis and Hemostasis, Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, Leiden, The Netherlands.,AP-HP, Hôpital Louis Mourier, Colombes, France
| | - Viola J F Strijbis
- Division of Thrombosis and Hemostasis, Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Ka Lei Cheung
- Division of Thrombosis and Hemostasis, Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Pieter H Reitsma
- Division of Thrombosis and Hemostasis, Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Mettine H A Bos
- Division of Thrombosis and Hemostasis, Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, Leiden, The Netherlands
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15
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Schreuder M, Reitsma PH, Bos MHA. Reversal Agents for the Direct Factor Xa Inhibitors: Biochemical Mechanisms of Current and Newly Emerging Therapies. Semin Thromb Hemost 2020; 46:986-998. [DOI: 10.1055/s-0040-1709134] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
AbstractThe direct oral anticoagulants targeting coagulation factor Xa or thrombin are widely used as alternatives to vitamin K antagonists in the management of venous thromboembolism and nonvalvular atrial fibrillation. In case of bleeding or emergency surgery, reversal agents are helpful to counteract the anticoagulant therapy and restore hemostasis. While idarucizumab has been established as an antidote for the direct thrombin inhibitor dabigatran, reversal strategies for the direct factor Xa inhibitors have been a focal point in clinical care over the past years. In the absence of specific reversal agents, the off-label use of (activated) prothrombin complex concentrate and recombinant factor VIIa have been suggested as effective treatment options during inhibitor-induced bleeding complications. Meanwhile, several specific reversal agents have been developed. In this review, an overview of the current state of nonspecific and specific reversal agents for the direct factor Xa inhibitors is provided, focusing on the biochemistry and mechanism of action and the preclinical assessment of newly emerging therapies.
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Affiliation(s)
- Mark Schreuder
- Division of Thrombosis and Hemostasis, Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Pieter H. Reitsma
- Division of Thrombosis and Hemostasis, Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Mettine H. A. Bos
- Division of Thrombosis and Hemostasis, Einthoven Laboratory for Vascular and Regenerative Medicine, Leiden University Medical Center, Leiden, The Netherlands
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16
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Zilberman-Rudenko J, Deguchi H, Shukla M, Oyama Y, Orje JN, Guo Z, Wyseure T, Mosnier LO, McCarty OJT, Ruggeri ZM, Eckle T, Griffin JH. Cardiac Myosin Promotes Thrombin Generation and Coagulation In Vitro and In Vivo. Arterioscler Thromb Vasc Biol 2020; 40:901-913. [PMID: 32102568 DOI: 10.1161/atvbaha.120.313990] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVE Cardiac myosin (CM) is structurally similar to skeletal muscle myosin, which has procoagulant activity. Here, we evaluated CM's ex vivo, in vivo, and in vitro activities related to hemostasis and thrombosis. Approach and Results: Perfusion of fresh human blood over CM-coated surfaces caused thrombus formation and fibrin deposition. Addition of CM to blood passing over collagen-coated surfaces enhanced fibrin formation. In a murine ischemia/reperfusion injury model, exogenous CM, when administered intravenously, augmented myocardial infarction and troponin I release. In hemophilia A mice, intravenously administered CM reduced tail-cut-initiated bleeding. These data provide proof of concept for CM's in vivo procoagulant properties. In vitro studies clarified some mechanisms for CM's procoagulant properties. Thrombin generation assays showed that CM, like skeletal muscle myosin, enhanced thrombin generation in human platelet-rich and platelet-poor plasmas and also in mixtures of purified factors Xa, Va, and prothrombin. Binding studies showed that CM, like skeletal muscle myosin, directly binds factor Xa, supporting the concept that the CM surface is a site for prothrombinase assembly. In tPA (tissue-type plasminogen activator)-induced plasma clot lysis assays, CM was antifibrinolytic due to robust CM-dependent thrombin generation that enhanced activation of TAFI (thrombin activatable fibrinolysis inhibitor). CONCLUSIONS CM in vitro is procoagulant and prothrombotic. CM in vivo can augment myocardial damage and can be prohemostatic in the presence of bleeding. CM's procoagulant and antifibrinolytic activities likely involve, at least in part, its ability to bind factor Xa and enhance thrombin generation. Future work is needed to clarify CM's pathophysiology and its mechanistic influences on hemostasis or thrombosis.
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Affiliation(s)
- Jevgenia Zilberman-Rudenko
- From the Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA (J.Z.-R., H.D., M.S., J.N.O., Z.G., T.W., L.O.M., Z.M.R., J.H.G.).,Department of Biomedical Engineering (J.Z.-R., O.J.T.M.), School of Medicine, Oregon Health & Science University, Portland
| | - Hiroshi Deguchi
- From the Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA (J.Z.-R., H.D., M.S., J.N.O., Z.G., T.W., L.O.M., Z.M.R., J.H.G.)
| | - Meenal Shukla
- From the Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA (J.Z.-R., H.D., M.S., J.N.O., Z.G., T.W., L.O.M., Z.M.R., J.H.G.)
| | - Yoshimasa Oyama
- Department of Hematology-Oncology (O.J.T.M.), School of Medicine, Oregon Health & Science University, Portland
| | - Jennifer N Orje
- From the Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA (J.Z.-R., H.D., M.S., J.N.O., Z.G., T.W., L.O.M., Z.M.R., J.H.G.)
| | - Zihan Guo
- From the Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA (J.Z.-R., H.D., M.S., J.N.O., Z.G., T.W., L.O.M., Z.M.R., J.H.G.)
| | - Tine Wyseure
- From the Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA (J.Z.-R., H.D., M.S., J.N.O., Z.G., T.W., L.O.M., Z.M.R., J.H.G.)
| | - Laurent O Mosnier
- From the Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA (J.Z.-R., H.D., M.S., J.N.O., Z.G., T.W., L.O.M., Z.M.R., J.H.G.)
| | - Owen J T McCarty
- Department of Biomedical Engineering (J.Z.-R., O.J.T.M.), School of Medicine, Oregon Health & Science University, Portland
| | - Zaverio M Ruggeri
- From the Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA (J.Z.-R., H.D., M.S., J.N.O., Z.G., T.W., L.O.M., Z.M.R., J.H.G.)
| | - Tobias Eckle
- Department of Hematology-Oncology (O.J.T.M.), School of Medicine, Oregon Health & Science University, Portland
| | - John H Griffin
- From the Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA (J.Z.-R., H.D., M.S., J.N.O., Z.G., T.W., L.O.M., Z.M.R., J.H.G.).,Department of Anesthesiology, University of Colorado School of Medicine, Aurora (Y.O., T.E.)
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17
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Role of the I16-D194 ionic interaction in the trypsin fold. Sci Rep 2019; 9:18035. [PMID: 31792294 PMCID: PMC6889508 DOI: 10.1038/s41598-019-54564-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 11/15/2019] [Indexed: 12/20/2022] Open
Abstract
Activity in trypsin-like proteases is the result of proteolytic cleavage at R15 followed by an ionic interaction that ensues between the new N terminus of I16 and the side chain of the highly conserved D194. This mechanism of activation, first proposed by Huber and Bode, organizes the oxyanion hole and primary specificity pocket for substrate binding and catalysis. Using the clotting protease thrombin as a relevant model, we unravel contributions of the I16-D194 ionic interaction to Na+ binding, stability of the transition state and the allosteric E*-E equilibrium of the trypsin fold. The I16T mutation abolishes the I16-D194 interaction and compromises the architecture of the oxyanion hole. The D194A mutation also abrogates the I16-D194 interaction but, surprisingly, has no effect on the architecture of the oxyanion hole that remains intact through a new H-bond established between G43 and G193. In both mutants, loss of the I16-D194 ionic interaction compromises Na+ binding, reduces stability of the transition state, collapses the 215–217 segment into the primary specific pocket and abrogates the allosteric E*-E equilibrium in favor of a rigid conformation that binds ligand at the active site according to a simple lock-and-key mechanism. These findings refine the structural role of the I16-D194 ionic interaction in the Huber-Bode mechanism of activation and reveal a functional linkage with the allosteric properties of the trypsin fold like Na+ binding and the E*-E equilibrium.
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18
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Evaluation of biomarkers for monitoring thrombogenic potential of FXaI16L. Blood Coagul Fibrinolysis 2019; 31:16-28. [PMID: 31687988 DOI: 10.1097/mbc.0000000000000866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
: A zymogen-like activated factor X variant (FXa) is being developed for treating acute bleeding conditions. Activated factor V is an essential cofactor to FXa for activating prothrombin to thrombin. Thrombi/emboli formation was observed microscopically in FXa toxicity studies in animals. The objective of this research was to evaluate candidate biomarkers for FXa-induced thrombi/emboli formation to inform safety monitoring and dose-escalation decisions in FXa clinical trials. Effects of intravenous FXa administration on platelets, fibrinogen, activated partial thromboplastin time (aPTT), prothrombin time (PT), D-dimer, tissue factor pathway inhibitor, thrombin : antithrombin complex, antithrombin, and factor V, and protein C (PC) activities were evaluated in mice, rats, and monkeys. Mice had endogenous factor V activity 10× that of monkeys and were overly sensitive to FXa-induced thrombi/emboli formation. In monkeys, decreases in fibrinogen and prolongation in aPTT and PT emerged as potential biomarkers for impending FXa-induced thrombi/emboli formation, based on association of changes with microscopically observable thrombi/emboli (0-97 thrombi/emboli per monkey). PC decreases, measured by a clot-based assay, were also observed. A similar reduction in PC activity, when measured by clot-based assay, was observed in a phase 1 clinical trial. However, an in-vitro experiment with human plasma spiked with increasing concentrations of FXa indicated dose-dependent FXa-induced interference with clot-based assays and no depletion of PC or S by FXa in non-clot-based assays. Nonclinical biomarker studies identified fibrinogen, aPTT and PT as potential biomarkers for monitoring the clinical safety of FXa. Results of clot-based assays with FXa treatment should be interpreted with caution.
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19
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Residues W215, E217 and E192 control the allosteric E*-E equilibrium of thrombin. Sci Rep 2019; 9:12304. [PMID: 31444378 PMCID: PMC6707225 DOI: 10.1038/s41598-019-48839-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 08/13/2019] [Indexed: 01/07/2023] Open
Abstract
A pre-existing, allosteric equilibrium between closed (E*) and open (E) conformations of the active site influences the level of activity in the trypsin fold and defines ligand binding according to the mechanism of conformational selection. Using the clotting protease thrombin as a model system, we investigate the molecular determinants of the E*-E equilibrium through rapid kinetics and X-ray structural biology. The equilibrium is controlled by three residues positioned around the active site. W215 on the 215-217 segment defining the west wall of the active site controls the rate of transition from E to E* through hydrophobic interaction with F227. E192 on the opposite 190-193 segment defining the east wall of the active site controls the rate of transition from E* to E through electrostatic repulsion of E217. The side chain of E217 acts as a lever that moves the entire 215-217 segment in the E*-E equilibrium. Removal of this side chain converts binding to the active site to a simple lock-and-key mechanism and freezes the conformation in a state intermediate between E* and E. These findings reveal a simple framework to understand the molecular basis of a key allosteric property of the trypsin fold.
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20
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Arce M, Pinto MP, Galleguillos M, Muñoz C, Lange S, Ramirez C, Erices R, Gonzalez P, Velasquez E, Tempio F, Lopez MN, Salazar-Onfray F, Cautivo K, Kalergis AM, Cruz S, Lladser Á, Lobos-González L, Valenzuela G, Olivares N, Sáez C, Koning T, Sánchez FA, Fuenzalida P, Godoy A, Contreras Orellana P, Leyton L, Lugano R, Dimberg A, Quest AFG, Owen GI. Coagulation Factor Xa Promotes Solid Tumor Growth, Experimental Metastasis and Endothelial Cell Activation. Cancers (Basel) 2019; 11:cancers11081103. [PMID: 31382462 PMCID: PMC6721564 DOI: 10.3390/cancers11081103] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 07/11/2019] [Accepted: 07/27/2019] [Indexed: 02/06/2023] Open
Abstract
Hypercoagulable state is linked to cancer progression; however, the precise role of the coagulation cascade is poorly described. Herein, we examined the contribution of a hypercoagulative state through the administration of intravenous Coagulation Factor Xa (FXa), on the growth of solid human tumors and the experimental metastasis of the B16F10 melanoma in mouse models. FXa increased solid tumor volume and lung, liver, kidney and lymph node metastasis of tail-vein injected B16F10 cells. Concentrating on the metastasis model, upon coadministration of the anticoagulant Dalteparin, lung metastasis was significantly reduced, and no metastasis was observed in other organs. FXa did not directly alter proliferation, migration or invasion of cancer cells in vitro. Alternatively, FXa upon endothelial cells promoted cytoskeleton contraction, disrupted membrane VE-Cadherin pattern, heightened endothelial-hyperpermeability, increased inflammatory adhesion molecules and enhanced B16F10 adhesion under flow conditions. Microarray analysis of endothelial cells treated with FXa demonstrated elevated expression of inflammatory transcripts. Accordingly, FXa treatment increased immune cell infiltration in mouse lungs, an effect reduced by dalteparin. Taken together, our results suggest that FXa increases B16F10 metastasis via endothelial cell activation and enhanced cancer cell-endothelium adhesion advocating that the coagulation system is not merely a bystander in the process of cancer metastasis.
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Affiliation(s)
- Maximiliano Arce
- Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
- Advanced Center for Chronic Diseases (ACCDiS), Santiago, Chile
| | - Mauricio P Pinto
- Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Macarena Galleguillos
- Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Catalina Muñoz
- Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Soledad Lange
- Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Carolina Ramirez
- Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Rafaela Erices
- Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
- Vicerrectoría de Investigación, Universidad Mayor, Santiago 7510041, Chile
| | - Pamela Gonzalez
- Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Ethel Velasquez
- Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
- Comisión Chilena de Energía Nuclear (CCHEN), Santiago, Chile
| | - Fabián Tempio
- Institute of Biomedical Sciences, Faculty of Medicine, University de Chile, Santiago 8380453, Chile
| | - Mercedes N Lopez
- Institute of Biomedical Sciences, Faculty of Medicine, University de Chile, Santiago 8380453, Chile
- Millennium Institute on Immunology and Immunotherapy, Santiago 8331150, Chile
| | - Flavio Salazar-Onfray
- Institute of Biomedical Sciences, Faculty of Medicine, University de Chile, Santiago 8380453, Chile
- Millennium Institute on Immunology and Immunotherapy, Santiago 8331150, Chile
| | - Kelly Cautivo
- Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Alexis M Kalergis
- Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
- Millennium Institute on Immunology and Immunotherapy, Santiago 8331150, Chile
- Biomedical Research Consortium of Chile, Santiago 8331010, Chile
| | - Sebastián Cruz
- Laboratory of Immunoncology, Fundación Ciencia & Vida, Santiago, Chile
| | - Álvaro Lladser
- Millennium Institute on Immunology and Immunotherapy, Santiago 8331150, Chile
- Laboratory of Immunoncology, Fundación Ciencia & Vida, Santiago, Chile
| | - Lorena Lobos-González
- Advanced Center for Chronic Diseases (ACCDiS), Santiago, Chile
- Laboratory of Immunoncology, Fundación Ciencia & Vida, Santiago, Chile
- Regenerative Medicine Center, Faculty of Medicine, Clinica Alemana-Universidad Del Desarrollo, Santiago 7650568, Chile
| | - Guillermo Valenzuela
- Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Nixa Olivares
- Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Claudia Sáez
- Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Tania Koning
- Immunology Institute, Faculty of Medicine, Universidad Austral de Chile, Valdivia 5110566, Chile
| | - Fabiola A Sánchez
- Immunology Institute, Faculty of Medicine, Universidad Austral de Chile, Valdivia 5110566, Chile
| | - Patricia Fuenzalida
- Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Alejandro Godoy
- Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
- Department of Urology, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14203, USA
| | - Pamela Contreras Orellana
- Advanced Center for Chronic Diseases (ACCDiS), Santiago, Chile
- Laboratory of Cellular Communication, ICBM, Faculty of Medicine, Universidad de Chile, Santiago 8380453, Chile
| | - Lisette Leyton
- Advanced Center for Chronic Diseases (ACCDiS), Santiago, Chile
- Laboratory of Cellular Communication, ICBM, Faculty of Medicine, Universidad de Chile, Santiago 8380453, Chile
| | - Roberta Lugano
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, 751 85 Uppsala, Sweden
| | - Anna Dimberg
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, 751 85 Uppsala, Sweden
| | - Andrew F G Quest
- Advanced Center for Chronic Diseases (ACCDiS), Santiago, Chile
- Laboratory of Cellular Communication, ICBM, Faculty of Medicine, Universidad de Chile, Santiago 8380453, Chile
| | - Gareth I Owen
- Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile.
- Advanced Center for Chronic Diseases (ACCDiS), Santiago, Chile.
- Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile.
- Millennium Institute on Immunology and Immunotherapy, Santiago 8331150, Chile.
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21
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Parng C, Bolt M, Pittman DD, Caiazzo T, Dyleski L, Gorovits B, Webster R. Induction and Impact of Anti-Drug Responses Elicited by a Human Recombinant Coagulation Factor FXa I16L in Preclinical Species. AAPS JOURNAL 2019; 21:52. [PMID: 30976993 DOI: 10.1208/s12248-019-0324-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 03/22/2019] [Indexed: 11/30/2022]
Abstract
This paper presents a systemic investigation of ADA development and ADA impact of a human coagulation factor in nonclinical species during drug development and provides insights into potential implications in human if a similar ADA occurs. FXaI16L-induced ADA response was characterized in monkey, mouse, rat, and dog in different studies, and ADA effects on pharmacokinetic and/or pharmacodynamics of FXaI16L were further examined in ADA-negative and ADA-positive animals. After repeated administrations, FXaI16L elicited a dose and exposure day-dependent ADA response which ranged from no response to a transient or persistent response. Increase in exposure day and increase in dose generally enhanced ADA incidence except for a decrease in ADA incidence was observed in monkeys after repeated high-dose administrations. The observable ADA impact on pharmacokinetics was only found in some ADA+ animals and included decrease in clearance and increase in systemic exposure but no increase in half-life. In addition, no or limited effect on pharmacodynamics by ADA was observed. The earliest ADA response was observed after three exposure days, marked elevation of drug exposure was observed in some animals at log titer > 2.0, and the highest antibody titer excited was about 4 (Log10) in all species. A correlation between ADA induction and accumulative exposure after various repeat treatments in different species was found for FXaI16L. In addition, potential immunogenicity risk and mitigation of ADA in clinics are discussed.
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Affiliation(s)
- Chuenlei Parng
- Pfizer Biomedicine Design, Pharmacokinetics Pharmacodynamics Metabolism, 610 Main St., Cambridge, Massachusetts, 02139, USA.
| | - Michael Bolt
- Pfizer Drug Safety Research and Development, Cambridge, Massachusetts, 02139, USA
| | - Debra D Pittman
- Pfizer Rare Disease Research Unit, Cambridge, Massachusetts, 02139, USA
| | - Teresa Caiazzo
- Pfizer Biomedicine Design, Andover, Massachusetts, 01810, USA
| | - Lisa Dyleski
- Pfizer Biomedicine Design, Andover, Massachusetts, 01810, USA
| | - Boris Gorovits
- Pfizer Biomedicine Design, Andover, Massachusetts, 01810, USA
| | - Rob Webster
- Pfizer Biomedicine Design, Pharmacokinetics Pharmacodynamics Metabolism, 610 Main St., Cambridge, Massachusetts, 02139, USA
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22
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Protein-Engineered Coagulation Factors for Hemophilia Gene Therapy. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2018; 12:184-201. [PMID: 30705923 PMCID: PMC6349562 DOI: 10.1016/j.omtm.2018.12.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Hemophilia A (HA) and hemophilia B (HB) are X-linked bleeding disorders due to inheritable deficiencies in either coagulation factor VIII (FVIII) or factor IX (FIX), respectively. Recently, gene therapy clinical trials with adeno-associated virus (AAV) vectors and protein-engineered transgenes, B-domain deleted (BDD) FVIII and FIX-Padua, have reported near-phenotypic cures in subjects with HA and HB, respectively. Here, we review the biology and the clinical development of FVIII-BDD and FIX-Padua as transgenes. We also examine alternative bioengineering strategies for FVIII and FIX, as well as the immunological challenges of these approaches. Other engineered proteins and their potential use in gene therapy for hemophilia with inhibitors are also discussed. Continued advancement of gene therapy for HA and HB using protein-engineered transgenes has the potential to alleviate the substantial medical and psychosocial burdens of the disease.
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23
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Plautz WE, Chattopadhyay R, Goldfeld EI, Samelson-Jones BJ, Pilli VS, Campello E, Datta A, Arruda VR, Simioni P, Majumder R. Padua FIXa resistance to Protein S and a potential therapy for hyperactive FIXa. Thromb Res 2018; 170:133-141. [PMID: 30189336 DOI: 10.1016/j.thromres.2018.08.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 08/08/2018] [Accepted: 08/24/2018] [Indexed: 10/28/2022]
Abstract
INTRODUCTION Abnormalities in the levels and functions of proteins that maintain hemostasis can cause thrombosis. Factor IX (FIX) R338L, i.e., Factor IX Padua, is a hyperactive clotting factor that promotes thrombosis. The R338L mutation increases the clotting rate by 8-fold despite increasing the Factor IXa enzymatic activity by only 2-fold. Protein S (PS) is a natural anticoagulant that directly inhibits FIXa. Because individuals affected by the R338L mutation have normal concentrations of PS, we speculated that the Padua hypercoagulation phenotype is due to decreased inhibition of FIXa R338L by PS. METHODS We measured the ability of PS to inhibit FIX R338L, and we assessed the ability of PS to mitigate the prothrombotic effect FIX R338L. RESULTS Plasma clotting assays demonstrated that 3-fold more PS was required to inhibit FIXa R338L compared with inhibition of wild type FIXa. Thrombin generation assays with Padua patient plasma recapitulated this biochemical consequence of the R338L mutation. Importantly, the less efficient inhibition of FIXa R338L was reversed by increasing PS concentration. Binding and co-immunoprecipitation studies revealed that the decrease in the inhibition of FIXa R338L by PS was caused by a 3- to 4-fold reduction in FIXa R338L affinity for PS. CONCLUSION In summary, the resistance of FIXa R338L to inhibition by PS likely contributes to the unexpectedly high clotting rate in Padua individuals. Moreover, PS-mediated reversal of the pathological properties of FIXa R338L suggests that PS administration may be a novel and effective means to mitigate thrombophilia caused by any source of elevated FIXa activity.
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Affiliation(s)
- William E Plautz
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, New Orleans, LA, United States of America
| | - Rima Chattopadhyay
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, New Orleans, LA, United States of America
| | - Ester I Goldfeld
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, New Orleans, LA, United States of America
| | - Benjamin J Samelson-Jones
- Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA, United States of America; Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Vijaya S Pilli
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, New Orleans, LA, United States of America
| | - Elena Campello
- Department of Medicine, Thrombotic and Hemorrhagic Diseases Unit, University of Padua Medical School, Padua, Italy
| | - Arani Datta
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, New Orleans, LA, United States of America
| | - Valder R Arruda
- Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA, United States of America; Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States; Raymond G. Perelman Center for Cellular and Molecular Therapeutics, Philadelphia, PA, United States
| | - Paolo Simioni
- Department of Medicine, Thrombotic and Hemorrhagic Diseases Unit, University of Padua Medical School, Padua, Italy
| | - Rinku Majumder
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, New Orleans, LA, United States of America.
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24
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Novel therapeutics for hemophilia and other bleeding disorders. Blood 2018; 132:23-30. [DOI: 10.1182/blood-2017-09-743385] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 04/17/2018] [Indexed: 11/20/2022] Open
Abstract
Abstract
Hemophilia and von Willebrand disease are the most common congenital bleeding disorders. Treatment of these disorders has focused on replacement of the missing coagulation factor to prevent or treat bleeding. New technologies and insights into hemostasis have driven the development of many promising new therapies for hemophilia and von Willebrand disease. Emerging bypass agents including zymogen-like factor IXa and Xa molecules are in development and a bispecific antibody, emicizumab, demonstrated efficacy in a phase 3 trial in people with hemophilia A and inhibitors. Tissue factor pathway inhibitor, the protein C/S system, and antithrombin are targets of novel compounds in development to alter the hemostatic balance and new approaches using modified factor VIII molecules are being tested for prevention and eradication of inhibitor antibodies in hemophilia A. The first recombinant von Willebrand factor (VWF) product has been approved and has unique VWF multimer content and does not contain factor VIII. These new approaches may offer better routes of administration, improved dosing regimens, and better efficacy for prevention and treatment of bleeding in congenital bleeding disorders.
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25
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Chakraborty P, Acquasaliente L, Pelc LA, Di Cera E. Interplay between conformational selection and zymogen activation. Sci Rep 2018; 8:4080. [PMID: 29511224 PMCID: PMC5840343 DOI: 10.1038/s41598-018-21728-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 02/09/2018] [Indexed: 11/09/2022] Open
Abstract
Trypsin-like proteases are synthesized as zymogens and activated through a mechanism that folds the active site for efficient binding and catalysis. Ligand binding to the active site is therefore a valuable source of information on the changes that accompany zymogen activation. Using the physiologically relevant transition of the clotting zymogen prothrombin to the mature protease thrombin, we show that the mechanism of ligand recognition follows selection within a pre-existing ensemble of conformations with the active site accessible (E) or inaccessible (E*) to binding. Prothrombin exists mainly in the E* conformational ensemble and conversion to thrombin produces two dominant changes: a progressive shift toward the E conformational ensemble triggered by removal of the auxiliary domains upon cleavage at R271 and a drastic drop of the rate of ligand dissociation from the active site triggered by cleavage at R320. Together, these effects produce a significant (700-fold) increase in binding affinity. Limited proteolysis reveals how the E*-E equilibrium shifts during prothrombin activation and influences exposure of the sites of cleavage at R271 and R320. These new findings on the molecular underpinnings of prothrombin activation are relevant to other zymogens with modular assembly involved in blood coagulation, complement and fibrinolysis.
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Affiliation(s)
- Pradipta Chakraborty
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, 63104, USA
| | - Laura Acquasaliente
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, 63104, USA
| | - Leslie A Pelc
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, 63104, USA
| | - Enrico Di Cera
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, 63104, USA.
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26
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Ragni MV. Novel alternate hemostatic agents for patients with inhibitors: beyond bypass therapy. HEMATOLOGY. AMERICAN SOCIETY OF HEMATOLOGY. EDUCATION PROGRAM 2017; 2017:605-609. [PMID: 29222310 PMCID: PMC6142579 DOI: 10.1182/asheducation-2017.1.605] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Inhibitor formation is among the most severe complications of hemophilia treatment. With a cumulative incidence of ∼30% in those with severe hemophilia A and ∼3% in those with severe hemophilia B, inhibitors are caused by a T-cell response directed against infused coagulation factor; these inhibitors neutralize factor VIII or IX activity and disrupt normal hemostasis. Inhibitor patients become unresponsive to standard factor treatment and, as an alternative, use bypass treatment (eg, recombinant factor VIIa or factor VIII inhibitor bypass activity). However, response to bypass agents is poorer and the burden of disease is higher, with greater morbidity, hospitalization, cost, and mortality, than in noninhibitor patients. Furthermore, inhibitor formation interferes with prophylaxis to prevent bleeding episodes and is a contraindication to gene therapy. Thus, more effective therapies for inhibitor patients are greatly needed. In the last several years, there has been an explosion of novel alternative hemostatic agents for hemophilia patients with and without inhibitors. These agents take advantage of technologic manipulation of coagulation factors and natural anticoagulants to promote hemostasis. The approaches include the following: (1) mutants or mimics of coagulation factors, rendering them resistant to natural anticoagulants; or (2) knock-down or disruption of natural anticoagulants, preventing degradation of coagulation factors. The purpose of this article was to review these novel alternative hemostatic agents and their mechanisms of action, as well as the preliminary pharmacokinetic, safety, and efficacy data available from early-phase clinical trials.
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Affiliation(s)
- Margaret V Ragni
- Department of Medicine, Division Hematology/Oncology, University of Pittsburgh, and Hemophilia Center of Western Pennsylvania, Pittsburgh, PA
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27
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Tanratana P, Ellery P, Westmark P, Mast AE, Sheehan JP. Elevated Plasma Factor IXa Activity in Premenopausal Women on Hormonal Contraception. Arterioscler Thromb Vasc Biol 2017; 38:266-274. [PMID: 29097362 DOI: 10.1161/atvbaha.117.309919] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 10/12/2017] [Indexed: 01/30/2023]
Abstract
OBJECTIVE Combined oral contraceptives induce a reversible hypercoagulable state with an enhanced risk of venous thromboembolism, but the underlying mechanism(s) remain unclear. Subjects on combined oral contraceptives also demonstrate a characteristic resistance to APC (activated protein C) in the thrombin generation assay. Here, we report the potential role of plasma factor IXa (FIXa) as a mechanism for hormone-induced systemic hypercoagulability. APPROACH AND RESULTS A novel assay was used to determine FIXa activity in plasma samples from volunteer blood donors. Plasma from 36 premenopausal females on hormonal contraception and 35 not on hormonal contraception, 35 postmenopausal females, and 10 males were analyzed for FIXa activity, total PS (protein S), total tissue factor pathway inhibitor (TFPI), and TFPI-α antigen. Premenopausal females on hormonal contraception demonstrated significantly increased FIXa activity and decreased TFPI-α compared with the other groups. Remarkably, FIXa values were not normally distributed in the hormonal contraception group, but skewed toward the high end. Plasma FIXa activity inversely correlated with both TFPI-α and total PS antigen. Ex vivo determination of TF-dependent FIX activation in FV-deficient plasma demonstrated that inhibitory anti-TFPI antibodies enhanced FIXa generation by 2- to 3-fold, whereas addition of 75 nmol/L PS reduced FIXa generation by ≈2-fold. Further, increasing FIXa concentration enhanced APC resistance during TF-triggered plasma thrombin generation. CONCLUSIONS Elevation of plasma FIXa activity in association with reductions in TFPI-α and PS is a potential mechanism for systemic hypercoagulability and resistance to APC in premenopausal females on hormonal contraception.
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Affiliation(s)
- Pansakorn Tanratana
- From the Department of Pathology and Laboratory Medicine (P.T.), Department of Medicine/Hematology-Oncology (P.W., J.P.S.), University of Wisconsin School of Medicine and Public Health, Madison; Department of Pharmacology, Faculty of Science, Mahidol University, Bangkok, Thailand (P.T.); Blood Research Institute, Blood Center of Wisconsin, Milwaukee (P.E., A.E.M.); and School of Biomedical Sciences, Curtin University, Perth, Western Australia, Australia (P.E.)
| | - Paul Ellery
- From the Department of Pathology and Laboratory Medicine (P.T.), Department of Medicine/Hematology-Oncology (P.W., J.P.S.), University of Wisconsin School of Medicine and Public Health, Madison; Department of Pharmacology, Faculty of Science, Mahidol University, Bangkok, Thailand (P.T.); Blood Research Institute, Blood Center of Wisconsin, Milwaukee (P.E., A.E.M.); and School of Biomedical Sciences, Curtin University, Perth, Western Australia, Australia (P.E.)
| | - Pamela Westmark
- From the Department of Pathology and Laboratory Medicine (P.T.), Department of Medicine/Hematology-Oncology (P.W., J.P.S.), University of Wisconsin School of Medicine and Public Health, Madison; Department of Pharmacology, Faculty of Science, Mahidol University, Bangkok, Thailand (P.T.); Blood Research Institute, Blood Center of Wisconsin, Milwaukee (P.E., A.E.M.); and School of Biomedical Sciences, Curtin University, Perth, Western Australia, Australia (P.E.)
| | - Alan E Mast
- From the Department of Pathology and Laboratory Medicine (P.T.), Department of Medicine/Hematology-Oncology (P.W., J.P.S.), University of Wisconsin School of Medicine and Public Health, Madison; Department of Pharmacology, Faculty of Science, Mahidol University, Bangkok, Thailand (P.T.); Blood Research Institute, Blood Center of Wisconsin, Milwaukee (P.E., A.E.M.); and School of Biomedical Sciences, Curtin University, Perth, Western Australia, Australia (P.E.)
| | - John P Sheehan
- From the Department of Pathology and Laboratory Medicine (P.T.), Department of Medicine/Hematology-Oncology (P.W., J.P.S.), University of Wisconsin School of Medicine and Public Health, Madison; Department of Pharmacology, Faculty of Science, Mahidol University, Bangkok, Thailand (P.T.); Blood Research Institute, Blood Center of Wisconsin, Milwaukee (P.E., A.E.M.); and School of Biomedical Sciences, Curtin University, Perth, Western Australia, Australia (P.E.).
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28
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Abstract
PURPOSE OF REVIEW New therapies are needed to control bleeding in a range of clinical conditions. This review will discuss the biochemical properties of zymogen-like factor Xa, its preclinical assessment in different model systems, and future development prospects. RECENT FINDINGS Underlying many procoagulant therapeutic approaches is the rapid generation of thrombin to promote robust clot formation. Clinically tested prohemostatic agents (e.g., factor VIIa) can provide effective hemostasis to mitigate bleeding in hemophilia and other clinical situations. Over the past decade, we explored the possibility of using zymogen-like factor Xa variants to rapidly improve clot formation for the treatment of bleeding conditions. Compared to the wild-type enzyme, these variants adopt an altered, low activity, conformation which enables them to resist plasma protease inhibitors. However, zymogen-like factor Xa variants are conformationally dynamic and ligands such as its cofactor, factor Va, stabilize the molecule rescuing procoagulant activity. At the site of vascular injury, the variants in the presence of factor Va serve as effective prohemostatic agents. Preclinical data support their use to stop bleeding in a variety of clinical settings. Phase 1 studies suggest that zymogen-like factor Xa is safe and well tolerated, and a phase 1b is ongoing to assess safety in patients with intracerebral hemorrhage. SUMMARY Zymogen-like factor Xa is a unique prohemostatic agent for the treatment of a range of bleeding conditions.
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Affiliation(s)
- Nabil K Thalji
- Division of Hematology, Department of Pediatrics, The Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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29
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Parsons-Rich D, Hua F, Li G, Kantaridis C, Pittman DD, Arkin S. Phase 1 dose-escalating study to evaluate the safety, pharmacokinetics, and pharmacodynamics of a recombinant factor Xa variant (FXa I16L ). J Thromb Haemost 2017; 15:931-937. [PMID: 28294526 DOI: 10.1111/jth.13673] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Indexed: 11/28/2022]
Abstract
Essentials FXaI16L is a recombinant zymogen-like variant of activated coagulation factor X (FXa). A phase 1 dose escalation clinical trial of FXaI16L was conducted in healthy adults. FXaI16L was safe and tolerated at doses up to 5 μg/kg; no dose-limiting toxicity was observed. Data support further development of FXaI16L for patients with acute hemorrhagic conditions. SUMMARY Background FXaI16L (PF-05230907) is a zymogen-like variant of activated factor X (FXa). It shows enhanced resistance to inactivation by endogenous inhibitors as compared with wild-type FXa, and restores hemostatic activity in non-clinical models of various bleeding conditions. Objectives To evaluate the safety, pharmacokinetics and pharmacodynamics of FXaI16L by performing a phase 1, first-in-human, dose-escalation clinical trial in healthy adult volunteers. Methods Participants were assigned to one of six ascending single-dose cohorts (0.1, 0.3, 1, 2, 3 or 5 μg kg-1 ), each planned to comprise six volunteers treated with FXaI16L and two treated with placebo. Assessments included safety monitoring, pharmacokinetic and pharmacodynamic (PD) analyses, and immunogenicity testing. Results The trial enrolled 49 male volunteers. Administration of a single intravenous bolus dose of FXaI16L was safe and tolerated at all dose levels tested, with no dose-limiting toxicity or serious adverse events. FXaI16L plasma levels appeared to increase dose-proportionally, with a half-life of ~ 4 min. Treatment-related PD changes were observed for activated partial thromboplastin time, thrombin generation assay, thrombin-antithrombin complexes, prothrombin fragment 1 + 2, and D-dimer. One volunteer had a weak and transient non-neutralizing antidrug antibody response, which did not cross-react with native FX or native FXa. Conclusions FXaI16L was safe and tolerated, and showed a pharmacologic effect in healthy adults when administered at doses up to 5 μg kg-1 . The safety profile, pharmacokinetics and pharmacodynamics observed in this clinical trial support the further development of FXaI16L for hemostatic treatment in individuals with acute hemorrhagic conditions.
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Affiliation(s)
- D Parsons-Rich
- PharmaTherapeutics Clinical Research, Pfizer Inc., Cambridge, MA, USA
| | - F Hua
- PharmaTherapeutics Clinical Research, Pfizer Inc., Cambridge, MA, USA
| | - G Li
- PharmaTherapeutics Clinical Research, Pfizer Inc., Collegeville, PA, USA
| | - C Kantaridis
- Pfizer Clinical Research Unit, Pfizer Inc., Brussels, Belgium
| | - D D Pittman
- Rare Disease Research, Pfizer Inc., Cambridge, MA, USA
| | - S Arkin
- Rare Disease Research, Pfizer Inc., Cambridge, MA, USA
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30
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Parng C, Markiewicz V, Chen J, Leary B, Duriga N, Dyleski L, Caiazzo T, Bolt M, Joyce A, Gorovits B, Pittman DD, Webster R. Preclinical Pharmacokinetics, Pharmacodynamics, Tissue Distribution, and Interspecies Scaling of Recombinant Human Coagulation Factor Xa I16L. J Pharm Sci 2017; 106:2136-2143. [PMID: 28389265 DOI: 10.1016/j.xphs.2017.03.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 03/22/2017] [Accepted: 03/27/2017] [Indexed: 02/03/2023]
Abstract
FXaI16L is a recombinant human FXa variant which is currently being evaluated in the clinic for treating intracerebral hemorrhage. The aim of our studies is to investigate overall pharmacokinetics, pharmacodynamics, and distribution of FXaI16L in preclinical species, and to understand its potential implication in human. Pharmacokinetics of FXaI16L was examined using active site probes and the results showed that FXaI16L displayed fast clearance, low volume of distribution, and a very short plasma resident time in mice, rats, and monkeys. When pharmacodynamics was examined in monkeys, concentration effects of FXaI16L on shortening of active partial prothrombin time and formation of thrombin-antithrombin complex were observed. Furthermore, biodistribution study was conducted in mice using radiolabeled FXaI16L, and showed that 125I-FXaI16L has high plasma protein binding and significant liver and kidney distribution. Human pharmacokinetic prediction for first-in-human dosing was evaluated using allometric scaling, liver blood flow, and a fixed coefficient method, and single species allometric scaling using monkey data was most predictive for human pharmacokinetics of FXaI16L.
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Affiliation(s)
- Chuenlei Parng
- Biomedicine Design, Pfizer Research and Development, Andover, Massachussetts 01810.
| | | | - Jianqing Chen
- Pfizer Quantitative Medicine, Cambridge, Massachussetts 02140
| | - Beth Leary
- Biomedicine Design, Pfizer Research and Development, Andover, Massachussetts 01810
| | - Nicole Duriga
- Biomedicine Design, Pfizer Research and Development, Andover, Massachussetts 01810
| | - Lisa Dyleski
- Biomedicine Design, Pfizer Research and Development, Andover, Massachussetts 01810
| | - Teresa Caiazzo
- Biomedicine Design, Pfizer Research and Development, Andover, Massachussetts 01810
| | - Michael Bolt
- Pfizer Drug Safety Research and Development, Groton, Connecticut 06340
| | - Alison Joyce
- Biomedicine Design, Pfizer Research and Development, Andover, Massachussetts 01810
| | - Boris Gorovits
- Biomedicine Design, Pfizer Research and Development, Andover, Massachussetts 01810
| | - Debra D Pittman
- Pfizer Rare Disease Research Unit, Hematology, Cambridge, Massachussetts 02140
| | - Robert Webster
- Biomedicine Design, Pfizer Research and Development, Andover, Massachussetts 01810
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31
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Abstract
There is a clinical need to develop safe and rapid therapeutic strategies to control bleeding arising from a host of emergent situations. Over the past several years our laboratory has developed novel zymogen-like FXa variants and tested their safety and efficacy using hemophilia as a model system. The variants have a spectrum of properties resulting from an amino acid change at the N-terminus of the heavy chain that alters a critical conformational change. These properties, which include resistance to plasma protease inhibitors, low activity in the absence of FVa, and rescue of low activity upon incorporation in prothrombinase, yield remarkably effective pro-hemostatic agents. The FVa-dependent restoration of activity is a key aspect to their efficacy and also contributes to localizing the variants to the site of vascular injury. While pre-clinical data support their use in the setting of hemophilia, they have the potential to act as rapid pro-hemostatic agents for the treatment of a range of bleeding conditions. This review will discuss the biochemical properties of these FXa zymogen-like variants and their in vivo characterization.
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Affiliation(s)
- Rodney M Camire
- The Children's Hospital of Philadelphia, The Raymond G. Perelman Center for Cellular and Molecular Therapeutics, and Division of Hematology, Department of Pediatrics, The University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104.
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32
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Lee D, Nayak S, Martin SW, Heatherington AC, Vicini P, Hua F. A quantitative systems pharmacology model of blood coagulation network describes in vivo biomarker changes in non-bleeding subjects. J Thromb Haemost 2016; 14:2430-2445. [PMID: 27666750 DOI: 10.1111/jth.13515] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 09/01/2016] [Indexed: 01/03/2023]
Abstract
Essentials Baseline coagulation activity can be detected in non-bleeding state by in vivo biomarker levels. A detailed mathematical model of coagulation was developed to describe the non-bleeding state. Optimized model described in vivo biomarkers with recombinant activated factor VII treatment. Sensitivity analysis predicted prothrombin fragment 1 + 2 and D-dimer are regulated differently. SUMMARY Background Prothrombin fragment 1 + 2 (F1 + 2 ), thrombin-antithrombin III complex (TAT) and D-dimer can be detected in plasma from non-bleeding hemostatically normal subjects or hemophilic patients. They are often used as safety or pharmacodynamic biomarkers for hemostatis-modulating therapies in the clinic, and provide insights into in vivo coagulation activity. Objectives To develop a quantitative systems pharmacology (QSP) model of the blood coagulation network to describe in vivo biomarkers, including F1 + 2 , TAT, and D-dimer, under non-bleeding conditions. Methods The QSP model included intrinsic and extrinsic coagulation pathways, platelet activation state-dependent kinetics, and a two-compartment pharmacokinetics model for recombinant activated factor VII (rFVIIa). Literature data on F1 + 2 and D-dimer at baseline and changes with rFVIIa treatment were used for parameter optimization. Multiparametric sensitivity analysis (MPSA) was used to understand key proteins that regulate F1 + 2 , TAT and D-dimer levels. Results The model was able to describe tissue factor (TF)-dependent baseline levels of F1 + 2 , TAT and D-dimer in a non-bleeding state, and their increases in hemostatically normal subjects and hemophilic patients treated with different doses of rFVIIa. The amount of TF required is predicted to be very low in a non-bleeding state. The model also predicts that these biomarker levels will be similar in hemostatically normal subjects and hemophilic patients. MPSA revealed that F1 + 2 and TAT levels are highly correlated, and that D-dimer is more sensitive to the perturbation of coagulation protein concentrations. Conclusions A QSP model for non-bleeding baseline coagulation activity was established with data from clinically relevant in vivo biomarkers at baseline and changes in response to rFVIIa treatment. This model will provide future mechanistic insights into this system.
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Affiliation(s)
- D Lee
- PharmaTherapeutics Clinical Research, Pfizer Inc., Cambridge, MA, USA
| | - S Nayak
- Pharmacometrics, Global Innovative Pharma Business, Pfizer Inc., Cambridge, MA, USA
| | - S W Martin
- Pharmacometrics, Global Innovative Pharma Business, Pfizer Inc., Cambridge, MA, USA
| | - A C Heatherington
- PharmaTherapeutics Clinical Research, Pfizer Inc., Cambridge, MA, USA
| | - P Vicini
- Pharmacokinetics, Dynamics and Metabolism - New Biological Entities, Pfizer Inc., San Diego, CA, USA
| | - F Hua
- PharmaTherapeutics Clinical Research, Pfizer Inc., Cambridge, MA, USA
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Affiliation(s)
- James C. Fredenburgh
- From the Departments of Medicine (J.C.F., J.I.W.) and Biochemistry and Biomedical Sciences (J.I.W.) and The Thrombosis and Atherosclerosis Research Institute (J.C.F., J.I.W.), McMaster University, Hamilton, ON, Canada
| | - Jeffrey I. Weitz
- From the Departments of Medicine (J.C.F., J.I.W.) and Biochemistry and Biomedical Sciences (J.I.W.) and The Thrombosis and Atherosclerosis Research Institute (J.C.F., J.I.W.), McMaster University, Hamilton, ON, Canada
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Pryzdial ELG, Meixner SC, Talbot K, Eltringham-Smith LJ, Baylis JR, Lee FMH, Kastrup CJ, Sheffield WP. Thrombolysis by chemically modified coagulation factor Xa. J Thromb Haemost 2016; 14:1844-54. [PMID: 27359348 PMCID: PMC5576980 DOI: 10.1111/jth.13402] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 06/15/2016] [Indexed: 12/22/2022]
Abstract
UNLABELLED Essentials Factor Xa (FXa) acquires cleavage-mediated tissue plasminogen activator (tPA) cofactor activity. Recombinant (r) tPA is the predominant thrombolytic drug, but it may cause systemic side effects. Chemically modified, non-enzymatic FXa was produced (Xai-K), which rapidly lysed thrombi in mice. Unlike rtPA, Xai-K had no systemic fibrinolysis activation markers, indicating improved safety. SUMMARY Background Enzymatic thrombolysis carries the risk of hemorrhage and re-occlusion must be evaded by co-administration with an anticoagulant. Toward further improving these shortcomings, we report a novel dual-functioning molecule, Xai-K, which is both a non-enzymatic thrombolytic agent and an anticoagulant. Xai-K is based on clotting factor Xa, whose sequential plasmin-mediated fragments, FXaβ and Xa33/13, accelerate the principal thrombolytic agent, tissue plasminogen activator (tPA), but only when localized to anionic phospholipid. Methods The effect of Xai-K on fibrinolysis was measured in vitro by turbidity, thromboelastography and chromogenic assays, and measured in a murine model of occlusive carotid thrombosis by Doppler ultrasound. The anticoagulant properties of Xai-K were evaluated by normal plasma clotting assays, and in murine liver laceration and tail amputation hemostatic models. Results Xa33/13, which participates in fibrinolysis of purified fibrin, was rapidly inhibited in plasma. Cleavage was blocked at FXaβ by modifying residues at the active site. The resultant Xai-K (1 nm) enhanced plasma clot dissolution by ~7-fold in vitro and was dependent on tPA. Xai-K alone (2.0 μg g(-1) body weight) achieved therapeutic patency in mice. The minimum primary dose of the tPA variant, Tenecteplase (TNK; 17 μg g(-1) ), could be reduced by > 30-fold to restore blood flow with adjunctive Xai-K (0.5 μg g(-1) ). TNK-induced systemic markers of fibrinolysis were not detected with Xai-K (2.0 μg g(-1) ). Xai-K had anticoagulant activity that was somewhat attenuated compared with a previously reported analogue. Conclusion These results suggest that Xai-K may ameliorate the safety profile of therapeutic thrombolysis, either as a primary or tPA/TNK-adjunctive agent.
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Affiliation(s)
- E L G Pryzdial
- Centre for Blood Research and Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada.
- Centre for Innovation, Canadian Blood Services, Ottawa, ON, Canada.
| | - S C Meixner
- Centre for Blood Research and Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
- Centre for Innovation, Canadian Blood Services, Ottawa, ON, Canada
| | - K Talbot
- Centre for Blood Research and Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
- Centre for Innovation, Canadian Blood Services, Ottawa, ON, Canada
| | - L J Eltringham-Smith
- Centre for Innovation, Canadian Blood Services, Ottawa, ON, Canada
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
| | - J R Baylis
- Centre for Blood Research and Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
- Michael Smith Laboratories and Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - F M H Lee
- Centre for Blood Research and Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
- Centre for Innovation, Canadian Blood Services, Ottawa, ON, Canada
| | - C J Kastrup
- Centre for Blood Research and Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
- Michael Smith Laboratories and Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - W P Sheffield
- Centre for Innovation, Canadian Blood Services, Ottawa, ON, Canada
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
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A rapid pro-hemostatic approach to overcome direct oral anticoagulants. Nat Med 2016; 22:924-32. [PMID: 27455511 DOI: 10.1038/nm.4149] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 06/16/2016] [Indexed: 02/07/2023]
Abstract
Direct inhibitors of coagulation factor Xa (FXa) or thrombin are promising oral anticoagulants that are becoming widely adopted. The ability to reverse their anticoagulant effects is important when serious bleeding occurs or urgent medical procedures are needed. Here, using experimental mouse models of hemostasis, we show that a variant coagulation factor, FXa(I16L), rapidly restores hemostasis in the presence of the anticoagulant effects of these inhibitors. The ability of FXa(I16L) to reverse the anticoagulant effects of FXa inhibitor depends, at least in part, on the ability of the active site inhibitor to hinder antithrombin-dependent FXa inactivation, paradoxically allowing uninhibited FXa to persist in plasma. Because of its inherent catalytic activity, FXa(I16L) is more potent (by >50-fold) in the hemostasis models tested than a noncatalytic antidote that is currently in clinical development. FXa(I16L) also reduces the anticoagulant-associated bleeding in vivo that is induced by the thrombin inhibitor dabigatran. FXa(I16L) may be able to fill an important unmet clinical need for a rapid, pro-hemostatic agent to reverse the effects of several new anticoagulants.
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Ragni MV. New and Emerging Agents for the Treatment of Hemophilia: Focus on Extended Half-Life Recombinant Clotting Proteins. Drugs 2016; 75:1587-600. [PMID: 26310188 DOI: 10.1007/s40265-015-0451-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Hemophilia A and B are X-linked disorders caused by deficient or defective clotting factor VIII (FVIII) or IX factor (FIX) proteins, and characterized by spontaneous or traumatic bleeding into joints and muscles. Previous use of plasma and plasma-derived clotting factors that lacked appropriate viral inactivation steps in manufacturing led to significant morbidity associated with transfusion-transmitted HIV and hepatitis C virus (HCV). The development of recombinant proteins revolutionized their treatment, and, with no new HIV or HCV infection via clotting proteins for nearly 30 years, greatly improved their lifespan, which now approaches that of the general population, and with the same risks for aging complications. Novel long-acting factor proteins are being licensed to extend FVIII and FIX half-life, thereby reducing infusion frequency and potentially bleed frequency and associated morbidity. Further, novel therapeutics which take advantage of new technologies, including siRNA, monoclonal antibody, and small peptide inhibition technologies, have the potential to simplify treatment and improve outcomes for those with inhibitors.
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Affiliation(s)
- Margaret V Ragni
- Division Hematology/Oncology, Department of Medicine, Hemophilia Center of Western Pennsylvania, University of Pittsburgh, 3636 Boulevard of the Allies, Pittsburgh, PA, 15213-4306, USA.
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Gale AJ, Bhat V, Pellequer JL, Griffin JH, Mosnier LO, Von Drygalski A. Safety, Stability and Pharmacokinetic Properties of (super)Factor Va, a Novel Engineered Coagulation Factor V for Treatment of Severe Bleeding. Pharm Res 2016; 33:1517-26. [PMID: 26960296 DOI: 10.1007/s11095-016-1895-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 03/01/2016] [Indexed: 11/30/2022]
Abstract
PURPOSE Activated (super)Factor V ((super)FVa) is a novel engineered FV with excellent prohemostatic efficacy. (Super)FVa has three APC cleavage site mutations and an interdomain disulfide bond. Stability, pharmacokinetics, and immunogenic and thrombogenic potential are reported here. METHODS Stability and circulating half-life were determined after incubation in buffer and human plasma, and after injection into FVIII-deficient mice. Immunogenicity potential was assessed by B- and T-cell specific epitope prediction and structural analysis using surface area and atomic depth computation. Thrombogenic potential was determined by quantification of lung fibrin deposition in wild-type mice after intravenous injection of (super)FVa (200 U/kg), recombinant human (rh) Tissue Factor (0.4-16 pmol/kg), rhFVIIa (3 mg/kg) or saline. RESULTS FVa retained full activity over 30 h in buffer, the functional half-life in human plasma was 4.9 h, and circulating half-life in FVIII-deficient mice was ~30 min. Predicted immunogenicity was not increased compared to human FV. While rh Tissue Factor, the positive control, resulted in pronounced lung fibrin depositions (mean 121 μg/mL), (super)FVa did not (6.7 μg/mL), and results were comparable to fibrin depositions with rhFVIIa (7.6 μg/mL) or saline (5.6 μg/mL). CONCLUSION FVa has an appropriate safety and stability profile for further preclinical development as a prohemostatic against severe bleeding.
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Affiliation(s)
- Andrew J Gale
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, 10550 N Torrey Pines Rd, La Jolla, California, USA. .,Avelas Biosciences, La Jolla, California, USA.
| | - Vikas Bhat
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, 10550 N Torrey Pines Rd, La Jolla, California, USA
| | - Jean-Luc Pellequer
- University Grenoble Alpes, IBS, F-38044, Grenoble, France.,CNRS, IBS, F-38044, Grenoble, France.,Methodology and Electron Microscopy Group, CEA, IBS, F-38044, Grenoble, France
| | - John H Griffin
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, 10550 N Torrey Pines Rd, La Jolla, California, USA.,Department of Medicine, Division of Hematology/Oncology, University California San Diego, San Diego, California, USA
| | - Laurent O Mosnier
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, 10550 N Torrey Pines Rd, La Jolla, California, USA
| | - Annette Von Drygalski
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, 10550 N Torrey Pines Rd, La Jolla, California, USA.,Department of Medicine, Division of Hematology/Oncology, University California San Diego, San Diego, California, USA
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Leissinger CA. Advances in the clinical management of inhibitors in hemophilia A and B. Semin Hematol 2015; 53:20-7. [PMID: 26805903 DOI: 10.1053/j.seminhematol.2015.10.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2004] [Revised: 11/05/2004] [Accepted: 12/01/2005] [Indexed: 01/25/2023]
Abstract
Inhibitors to factor (F)VIII or FIX are the most serious and challenging complication of hemophilia treatment, increasing morbidity and mortality because bleeds no longer respond to standard clotting factor replacement therapy. For patients with high-titer inhibitors, immune tolerance induction achieved through regular factor exposure is the only proven therapy capable of Inhibitor eradication and is almost always indicated for inhibitors of recent onset. Bypassing therapy is used to treat and prevent bleeding, but neither of the two currently available bypassing agents has the predictable hemostatic efficacy of factor replacement in hemophilia patients without inhibitors. Major research efforts are focused on the development of new, more potent therapies for the management of patients with inhibitors.
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Affiliation(s)
- Cindy A Leissinger
- Departments of Medicine, Pediatrics, and Pathology, Tulane University School of Medicine, New Orleans, LA, USA.
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Abstract
Current developments in haemophilia therapy are directed at two therapeutic targets: reduction of injection frequency and reduction or bypassing of inhibitors. A variety of new molecules addressing these aims are now completing clinical trials and are ready to enter clinical use. First amongst these are modified Factor VIII (FVIII) and Factor IX (FIX) molecules with extended half-lives. FIX modifications have achieved 5-fold prolongation of half-life whilst effects on FVIII have been more modest, at less than two-fold. We now face the problem of integrating these into clinical practice. Other approaches have generated chemically modified FVIII molecules with altered activation profiles. An alternative way of correcting the haemophilia defect is to reduce the activity of natural anticoagulants in an attempt to restore the balance of haemostasis. These methods are also giving promising results but, as with all new approaches, it will be some while before they all find their place in practice.
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Affiliation(s)
- Mike Laffan
- Centre for Haematology, Imperial College London, London, UK
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40
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George LA, Thalji NK, Raffini LJ, Gimotty PA, Camire RM. Correction of human hemophilia A whole blood abnormalities with a novel bypass agent: zymogen-like FXa(I16L). J Thromb Haemost 2015; 13:1694-8. [PMID: 26190406 DOI: 10.1111/jth.13059] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 07/08/2015] [Indexed: 11/29/2022]
Abstract
BACKGROUND Approximately 30% of hemophilia A (HA) and 5% of hemophilia B patients develop inhibitors to protein replacement therapy, and this is the major cause of disease-related morbidity in the developed world. We previously developed zymogen-like factor Xa (FXa) molecules with impaired active site maturation, enabling a greater half-life than wild-type FXa while maintaining full procoagulant function in the prothrombinase complex. Here we evaluated the ability of zymogen-like FXa(I16L) to correct whole blood thromboelastometry abnormalities of severe HA subjects with and without inhibitors. METHODS Fourteen severe HA subjects without and five with inhibitors were enrolled at baseline ( FVIII C < 1%) > 5 half-lives from factor or bypass therapy. The subjects' whole blood was evaluated by thromboelastography (ROTEM(®) ) using INTEM analysis with two concentrations of FXa(I16L) or recombinant factor VIIa (rFVIIa). RESULTS With 0.1 nm FXa(I16L) , clot time (CT, in minutes [min]) among HA subjects without and with inhibitors (mean = 2.87 min, 95% CI = 2.58-3.15 min, and mean = 2.9 min, 95% CI = 2.07-3.73 min, respectively) did not significantly differ from control CT (mean = 2.73 min, 95% CI = 2.62-2.85 min). Addition of 20 nm rFVIIa, simulating a 90-μg/kg dose, resulted in significantly prolonged CTs for HA subjects without and with inhibitors (mean = 5.43 min, 95% CI = 4.53-6.35 min, and mean = 4.25 min, 95% CI = 3.32-5.17 min, respectively) relative to controls. CONCLUSIONS FXa(I16L) restored thromboelastometry CT to control values in severe HA subjects with and without inhibitors. The findings corroborate previous animal data and demonstrate the first evidence of zymogen-like FXa(I16L) correcting human HA subjects' whole-blood abnormalities and support the use of FXa(I16L) as a novel hemostatic agent.
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Affiliation(s)
- L A George
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - N K Thalji
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - L J Raffini
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - P A Gimotty
- Department of Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - R M Camire
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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42
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Westmark PR, Tanratana P, Sheehan JP. Selective disruption of heparin and antithrombin-mediated regulation of human factor IX. J Thromb Haemost 2015; 13:1053-63. [PMID: 25851619 DOI: 10.1111/jth.12960] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 03/24/2015] [Indexed: 12/01/2022]
Abstract
BACKGROUND Interaction with antithrombin and heparin regulates distribution, activity, and clearance of factor IXa (FIXa). Hemophilia B prophylaxis targets plasma FIX levels > 1% but neglects extravascular FIX, which colocalizes with antithrombin-heparan sulfate. OBJECTIVE Combined mutagenesis of FIX was undertaken to selectively disrupt heparin- and antithrombin-mediated regulation of the protease. METHODS Human FIX alanine substitutions in the heparin (K126A and K132A) and antithrombin (R150A) exosites were characterized with regard to coagulant activity, plasma thrombin generation, antithrombin inhibition, and plasma half-life. RESULTS Single or combined (K126A/R150A or K132A/R150A) exosite mutations variably reduced coagulant activity relative to wild-type (WT) for FIX (27-91%) and FIXa (25-91%). Double mutation in the heparin exosite (K126A/K132A and K126A/K132A/R150A) markedly reduced coagulant activity (7-21%) and plasma TG. In contrast to coagulant activity, FIX K126A (1.8-fold), R150 (1.6-fold), and K132A/R150A (1.3-fold) supported increased tissue factor-initiated plasma TG, while FIX K132A and K126A/R150A were similar to WT. FIXa K126A/R150A and K132A/R150A (1.5-fold) demonstrated significantly increased FIXa-initiated TG, while FIXa K132A, R150A, and K126A (0.8-0.9-fold) were similar to WT. Dual mutations in the heparin exosite or combined mutations in both exosites synergistically reduced the inhibition rate for antithrombin-heparin. The half-life of FIXa WT in FIX-deficient plasma was remarkably lengthy (40.9 ±1.4 min) and further prolonged for FIXa R150A, K126A/R150A, and K132A/R150A (> 2 h). CONCLUSION Selective disruption of exosite-mediated regulation by heparin and antithrombin can be achieved with preserved or enhanced thrombin generation capacity. These proteins should demonstrate enhanced therapeutic efficacy for hemophilia B.
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Affiliation(s)
- P R Westmark
- Department of Medicine/Hematology-Oncology, University of Wisconsin-Madison, Madison, WI, USA
| | - P Tanratana
- Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison, WI, USA
- Department of Pharmacology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - J P Sheehan
- Department of Medicine/Hematology-Oncology, University of Wisconsin-Madison, Madison, WI, USA
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Hemostatic agents of broad applicability produced by selective tuning of factor Xa zymogenicity. Blood 2015; 126:94-102. [PMID: 25896653 DOI: 10.1182/blood-2015-03-634329] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 04/15/2015] [Indexed: 01/01/2023] Open
Abstract
There is a clinical need to develop safe therapeutic strategies to mitigate bleeding. Previously, we found that a novel zymogen-like factor Xa variant (FXa-I16L) was effective in correcting the coagulation defect in hemophilic mice. Here we expand the mutational framework to tune the FX(a) zymogen-like state. Alteration of FXa zymogenicity yields variants (V17M, I16L, I16M, V17T, V17S, and I16T) with a wide range (≤1000-fold) of reduced function toward physiologic substrates and inhibitors. The extent of zymogen-like character, including resistance to antithrombin III, correlates well with plasma half-life (<2 minutes to >4 hours). Importantly, biologic function, including that of the most zymogen-like variant (FXa-I16T), was greatly enhanced when bound to FVa membranes. This resulted in improvement of clotting times and thrombin generation in hemophilic plasma. The FXa variants were remarkably effective in mouse injury models. In these systems, the data show that the more active the protease, the more difficult it is to overcome the protective mechanism of circulating inhibitors to achieve a therapeutic benefit. Depending on the treatment situation, the more zymogen-like variants (V17S and I16T) were most useful when given before injury whereas variants exhibiting greater activity but shorter half-lives (I16L and I16M) were most effective when administered after injury. This new class of FXa variants provides a useful and flexible platform for selectively bioengineering biologic function and half-life to target different clinical bleeding scenarios.
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Pathak M, Wilmann P, Awford J, Li C, Hamad BK, Fischer PM, Dreveny I, Dekker LV, Emsley J. Coagulation factor XII protease domain crystal structure. J Thromb Haemost 2015; 13:580-91. [PMID: 25604127 PMCID: PMC4418343 DOI: 10.1111/jth.12849] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 01/12/2015] [Indexed: 12/11/2022]
Abstract
BACKGROUND Coagulation factor XII is a serine protease that is important for kinin generation and blood coagulation, cleaving the substrates plasma kallikrein and FXI. OBJECTIVE To investigate FXII zymogen activation and substrate recognition by determining the crystal structure of the FXII protease domain. METHODS AND RESULTS A series of recombinant FXII protease constructs were characterized by measurement of cleavage of chromogenic peptide and plasma kallikrein protein substrates. This revealed that the FXII protease construct spanning the light chain has unexpectedly weak proteolytic activity compared to β-FXIIa, which has an additional nine amino acid remnant of the heavy chain present. Consistent with these data, the crystal structure of the light chain protease reveals a zymogen conformation for active site residues Gly193 and Ser195, where the oxyanion hole is absent. The Asp194 side chain salt bridge to Arg73 constitutes an atypical conformation of the 70-loop. In one crystal form, the S1 pocket loops are partially flexible, which is typical of a zymogen. In a second crystal form of the deglycosylated light chain, the S1 pocket loops are ordered, and a short α-helix in the 180-loop of the structure results in an enlarged and distorted S1 pocket with a buried conformation of Asp189, which is critical for P1 Arg substrate recognition. The FXII structures define patches of negative charge surrounding the active site cleft that may be critical for interactions with inhibitors and substrates. CONCLUSIONS These data provide the first structural basis for understanding FXII substrate recognition and zymogen activation.
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Affiliation(s)
- M Pathak
- Centre for Biomolecular Sciences, School of Pharmacy, University of Nottingham, Nottingham, UK
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Zeller MP, Al-Habsi KS, Golder M, Walsh GM, Sheffield WP. Plasma and Plasma Protein Product Transfusion: A Canadian Blood Services Centre for Innovation Symposium. Transfus Med Rev 2015; 29:181-94. [PMID: 25862281 DOI: 10.1016/j.tmrv.2015.03.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2015] [Revised: 03/12/2015] [Accepted: 03/13/2015] [Indexed: 12/27/2022]
Abstract
Plasma obtained via whole blood donation processing or via apheresis technology can either be transfused directly to patients or pooled and fractionated into plasma protein products that are concentrates of 1 or more purified plasma protein. The evidence base supporting clinical efficacy in most of the indications for which plasma is transfused is weak, whereas high-quality evidence supports the efficacy of plasma protein products in at least some of the clinical settings in which they are used. Transfusable plasma utilization remains composed in part of applications that fall outside of clinical practice guidelines. Plasma contains all of the soluble coagulation factors and is frequently transfused in efforts to restore or reinforce patient hemostasis. The biochemical complexities of coagulation have in recent years been rationalized in newer cell-based models that supplement the cascade hypothesis. Efforts to normalize widely used clinical hemostasis screening test values by plasma transfusion are thought to be misplaced, but superior rapid tests have been slow to emerge. The advent of non-vitamin K-dependent oral anticoagulants has brought new challenges to clinical laboratories in plasma testing and to clinicians needing to reverse non-vitamin K-dependent oral anticoagulants urgently. Current plasma-related controversies include prophylactic plasma transfusion before invasive procedures, plasma vs prothrombin complex concentrates for urgent warfarin reversal, and the utility of increased ratios of plasma to red blood cell units transfused in massive transfusion protocols. The first recombinant plasma protein products to reach the clinic were recombinant hemophilia treatment products, and these donor-free equivalents to factors VIII and IX are now being supplemented with novel products whose circulatory half-lives have been increased by chemical modification or genetic fusion. Achieving optimal plasma utilization is an ongoing challenge in the interconnected worlds of transfusable plasma, plasma protein products, and recombinant and engineered replacements.
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Affiliation(s)
- Michelle P Zeller
- Centre for Innovation, Medical Services and Innovation, Canadian Blood Services, Hamilton, Ottawa, Vancouver, Canada; Department of Medicine, McMaster University, Hamilton, Canada
| | - Khalid S Al-Habsi
- Centre for Innovation, Medical Services and Innovation, Canadian Blood Services, Hamilton, Ottawa, Vancouver, Canada; Department of Medicine, McMaster University, Hamilton, Canada
| | - Mia Golder
- Centre for Innovation, Medical Services and Innovation, Canadian Blood Services, Hamilton, Ottawa, Vancouver, Canada
| | - Geraldine M Walsh
- Centre for Innovation, Medical Services and Innovation, Canadian Blood Services, Hamilton, Ottawa, Vancouver, Canada
| | - William P Sheffield
- Centre for Innovation, Medical Services and Innovation, Canadian Blood Services, Hamilton, Ottawa, Vancouver, Canada; Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Canada.
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Shetty S, Ghosh K. Novel therapeutic approaches for haemophilia. Haemophilia 2014; 21:152-161. [DOI: 10.1111/hae.12615] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/22/2014] [Indexed: 01/11/2023]
Affiliation(s)
- S. Shetty
- Department of Thrombosis and Haemostasis National Institute of Immunohaematology (ICMR) KEM Hospital Mumbai India
| | - K. Ghosh
- Department of Thrombosis and Haemostasis National Institute of Immunohaematology (ICMR) KEM Hospital Mumbai India
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Shetty SD, Ghosh K. Challenges and open issues in the management of acquired hemophilia A (AHA). Blood Cells Mol Dis 2014; 54:275-80. [PMID: 25486929 DOI: 10.1016/j.bcmd.2014.11.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 11/15/2014] [Indexed: 01/19/2023]
Abstract
Acquired hemophilia A (AHA) is a rare autoimmune bleeding disorder caused by antibodies which neutralize the function of factor VIII (FVIII). The disease presents a complex clinical challenge to the treating Physicians and Hematologists. As the disease is associated with high mortality, prompt management is necessary. Early recognition, quick diagnosis and timely referral to a specialized center are important for better management of these patients. The different clinical manifestations, underlying pathology, inhibitor kinetics and the associated age related comorbidities do not allow extrapolation of the treatment protocols of congenital hemophilia to AHA. The basic strategies of the management of AHA patients involve maintaining hemostasis, suppression or eradication of antibodies, diagnosis and treatment of underlying pathology and avoid treatment related complications like thrombosis. The efficiency of hemostatic agents which are generally used to treat AHA is unpredictable. Due to the rarity of the disease, there are no randomized clinical trials on the management of this disorder and thus the expertise and experience of the treating Physicians' guide treatment strategies.
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Affiliation(s)
- Shrimati D Shetty
- National Institute of Immunohaematology (ICMR), Department of Thrombosis and Haemostasis, 13th Floor, KEM Hospital, Parel, Mumbai, India.
| | - Kanjaksha Ghosh
- National Institute of Immunohaematology (ICMR), Department of Thrombosis and Haemostasis, 13th Floor, KEM Hospital, Parel, Mumbai, India
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48
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Promising coagulation factor VIII bypassing strategies for patients with haemophilia A. Blood Coagul Fibrinolysis 2014; 25:539-52. [DOI: 10.1097/mbc.0000000000000098] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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The endothelial protein C receptor enhances hemostasis of FVIIa administration in hemophilic mice in vivo. Blood 2014; 124:1157-65. [PMID: 24957146 DOI: 10.1182/blood-2014-04-567297] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Recombinant activated human factor VII (rhFVIIa) is an established hemostatic agent in hemophilia, but its mechanism of action remains unclear. Although tissue factor (TF) is its natural receptor, rhFVIIa also interacts with the endothelial protein C receptor (EPCR) through its γ-carboxyglutamic acid (Gla) domain, with unknown hemostatic consequences in vivo. Here, we study whether EPCR facilitates rhFVIIa hemostasis in hemophilia using a mouse model system. Mouse activated FVII (mFVIIa) is functionally homologous to rhFVIIa, but binds poorly to mouse EPCR (mEPCR). We modified mFVIIa to gain mEPCR binding using 3 amino acid changes in its Gla domain (L4F/L8M/W9R). The resulting molecule mFVIIa-FMR specifically bound mEPCR in vitro and in vivo and was identical to mFVIIa with respect to TF affinity and procoagulant functions. In macrovascular injury models, hemophilic mice administered mFVIIa-FMR exhibited superior hemostatic activity compared with mFVIIa. This was abolished by blocking mEPCR and was absent in ex vivo whole blood coagulation assays, implicating a specific mFVIIa-FMR and endothelial mEPCR interaction. Because mFVIIa-FMR models the TF-dependent and EPCR binding properties of rhFVIIa, our data unmask a novel contribution of EPCR on the action of rhFVIIa administration in hemophilia, prompting the rational design of improved and safer rhFVIIa therapeutics.
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Abstract
The prothrombinase complex, composed of the protease factor (f)Xa and cofactor fVa, efficiently converts prothrombin to thrombin by specific sequential cleavage at 2 sites. How the complex assembles and its mechanism of prothrombin processing are of central importance to human health and disease, because insufficient thrombin generation is the root cause of hemophilia, and excessive thrombin production results in thrombosis. Efforts to determine the crystal structure of the prothrombinase complex have been thwarted by the dependence of complex formation on phospholipid membrane association. Pseutarin C is an intrinsically stable prothrombinase complex preassembled in the venom gland of the Australian Eastern Brown Snake (Pseudonaja textilis). Here we report the crystal structures of the fX-fV complex and of activated fXa from P textilis venom and the derived model of active pseutarin C. Structural analysis supports a single substrate binding channel on fVa, to which prothrombin and the intermediate meizothrombin bind in 2 different orientations, providing insight into the architecture and mechanism of the prothrombinase complex-the molecular engine of blood coagulation.
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