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Acquasaliente L, Pierangelini A, Pagotto A, Pozzi N, De Filippis V. From haemadin to haemanorm: Synthesis and characterization of full-length haemadin from the leech Haemadipsa sylvestris and of a novel bivalent, highly potent thrombin inhibitor (haemanorm). Protein Sci 2023; 32:e4825. [PMID: 37924304 PMCID: PMC10683372 DOI: 10.1002/pro.4825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 10/25/2023] [Accepted: 10/27/2023] [Indexed: 11/06/2023]
Abstract
Hirudin from Hirudo medicinalis is a bivalent α-Thrombin (αT) inhibitor, targeting the enzyme active site and exosite-I, and is currently used in anticoagulant therapy along with its simplified analogue hirulog. Haemadin, a small protein (57 amino acids) isolated from the land-living leech Haemadipsa sylvestris, selectively inhibits αT with a potency identical to that of recombinant hirudin (KI = 0.2 pM), with which it shares a common disulfide topology and overall fold. At variance with hirudin, haemadin targets exosite-II and therefore (besides the free protease) it also blocks thrombomodulin-bound αT without inhibiting the active intermediate meizothrombin, thus offering potential advantages over hirudin. Here, we produced in reasonably high yields and pharmaceutical purity (>98%) wild-type haemadin and the oxidation resistant Met5 → nor-Leucine analogue, both inhibiting αT with a KI of 0.2 pM. Thereafter, we used site-directed mutagenesis, spectroscopic, ligand-displacement, and Hydrogen/Deuterium Exchange-Mass Spectrometry techniques to map the αT regions relevant for the interaction with full-length haemadin and with the synthetic N- and C-terminal peptides Haem(1-10) and Haem(45-57). Haem(1-10) competitively binds to/inhibits αT active site (KI = 1.9 μM) and its potency was enhanced by 10-fold after Phe3 → β-Naphthylalanine exchange. Conversely to full-length haemadin, haem(45-57) displays intrinsic affinity for exosite-I (KD = 1.6 μM). Hence, we synthesized a peptide in which the sequences 1-9 and 45-57 were joined together through a 3-Glycine spacer to yield haemanorm, a highly potent (KI = 0.8 nM) inhibitor targeting αT active site and exosite-I. Haemanorm can be regarded as a novel class of hirulog-like αT inhibitors with potential pharmacological applications.
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Affiliation(s)
- Laura Acquasaliente
- Laboratory of Protein Chemistry & Molecular Hematology, Department of Pharmaceutical and Pharmacological Sciences, School of MedicineUniversity of PadovaPaduaItaly
| | - Andrea Pierangelini
- Laboratory of Protein Chemistry & Molecular Hematology, Department of Pharmaceutical and Pharmacological Sciences, School of MedicineUniversity of PadovaPaduaItaly
| | - Anna Pagotto
- Laboratory of Protein Chemistry & Molecular Hematology, Department of Pharmaceutical and Pharmacological Sciences, School of MedicineUniversity of PadovaPaduaItaly
| | - Nicola Pozzi
- Laboratory of Protein Chemistry & Molecular Hematology, Department of Pharmaceutical and Pharmacological Sciences, School of MedicineUniversity of PadovaPaduaItaly
- Department of Biochemistry and Molecular Biology, Edward A. Doisy Research CenterSaint Louis UniversitySt. LouisMissouriUSA
| | - Vincenzo De Filippis
- Laboratory of Protein Chemistry & Molecular Hematology, Department of Pharmaceutical and Pharmacological Sciences, School of MedicineUniversity of PadovaPaduaItaly
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Valenta J, Hlavackova A, Stach Z, Stikarova J, Havlicek M, Michalek P. Fibrinogenolysis in Venom-Induced Consumption Coagulopathy after Viperidae Snakebites: A Pilot Study. Toxins (Basel) 2022; 14:toxins14080538. [PMID: 36006200 PMCID: PMC9415103 DOI: 10.3390/toxins14080538] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 07/26/2022] [Accepted: 08/03/2022] [Indexed: 01/23/2023] Open
Abstract
Envenomations that are caused by Viperidae snakebites are mostly accompanied by venom-induced consumption coagulopathy (VICC) with defibrination. The clinical course of VICC is well described; however, reports about its detailed effects in the hemocoagulation systems of patients are sparse. In this pilot study, we prospectively analyzed the changes in plasma fibrinogen that were caused by the envenomation of six patients by five non-European Viperidae snakes. Western blot analysis was employed and fibrinogen fragments were visualized with the use of specific anti-human fibrinogen antibodies. All of the studied subjects experienced hypo- or afibrinogenemia. The western blot analysis demonstrated fibrinogenolysis of the fibrinogen chains in all of the cases. Fibrinogenolysis was considered to be a predominant cause of defibrination in Crotalus, Echis, and Macrovipera envenomation; while, in the cases of VICC that were caused by Atheris and Calloselasma envenomation, the splitting of the fibrinogen chains was present less significantly.
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Affiliation(s)
- Jiri Valenta
- Department of Anaesthesiology and Intensive Medicine, Toxinology Center, First Medical Faculty, Charles University, General University Hospital, U Nemocnice 499/2, 128 08 Prague, Czech Republic
| | - Alzbeta Hlavackova
- Department of Biochemistry, Institute of Hematology and Blood Transfusion, U Nemocnice 2094/1, 128 00 Prague, Czech Republic
- Correspondence: (A.H.); (P.M.); Tel.: +420-22197-7344 (A.H.); +420-22496-2666 (P.M.)
| | - Zdenek Stach
- Department of Anaesthesiology and Intensive Medicine, Toxinology Center, First Medical Faculty, Charles University, General University Hospital, U Nemocnice 499/2, 128 08 Prague, Czech Republic
| | - Jana Stikarova
- Department of Biochemistry, Institute of Hematology and Blood Transfusion, U Nemocnice 2094/1, 128 00 Prague, Czech Republic
| | - Marek Havlicek
- Department of Biochemistry, Institute of Hematology and Blood Transfusion, U Nemocnice 2094/1, 128 00 Prague, Czech Republic
| | - Pavel Michalek
- Department of Anaesthesiology and Intensive Medicine, Toxinology Center, First Medical Faculty, Charles University, General University Hospital, U Nemocnice 499/2, 128 08 Prague, Czech Republic
- Correspondence: (A.H.); (P.M.); Tel.: +420-22197-7344 (A.H.); +420-22496-2666 (P.M.)
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3
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Acquasaliente L, Pontarollo G, Radu CM, Peterle D, Artusi I, Pagotto A, Uliana F, Negro A, Simioni P, De Filippis V. Exogenous human α-Synuclein acts in vitro as a mild platelet antiaggregant inhibiting α-thrombin-induced platelet activation. Sci Rep 2022; 12:9880. [PMID: 35701444 PMCID: PMC9198058 DOI: 10.1038/s41598-022-12886-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 05/18/2022] [Indexed: 11/29/2022] Open
Abstract
α-Synuclein (αSyn) is a small disordered protein, highly conserved in vertebrates and involved in the pathogenesis of Parkinson’s disease (PD). Indeed, αSyn amyloid aggregates are present in the brain of patients with PD. Although the pathogenic role of αSyn is widely accepted, the physiological function of this protein remains elusive. Beyond the central nervous system, αSyn is expressed in hematopoietic tissue and blood, where platelets are a major cellular host of αSyn. Platelets play a key role in hemostasis and are potently activated by thrombin (αT) through the cleavage of protease-activated receptors. Furthermore, both αT and αSyn could be found in the same spatial environment, i.e. the platelet membrane, as αT binds to and activates platelets that can release αSyn from α-granules and microvesicles. Here, we investigated the possibility that exogenous αSyn could interfere with platelet activation induced by different agonists in vitro. Data obtained from distinct experimental techniques (i.e. multiple electrode aggregometry, rotational thromboelastometry, immunofluorescence microscopy, surface plasmon resonance, and steady-state fluorescence spectroscopy) on whole blood and platelet-rich plasma indicate that exogenous αSyn has mild platelet antiaggregating properties in vitro, acting as a negative regulator of αT-mediated platelet activation by preferentially inhibiting P-selectin expression on platelet surface. We have also shown that both exogenous and endogenous (i.e. cytoplasmic) αSyn preferentially bind to the outer surface of activated platelets. Starting from these findings, a coherent model of the antiplatelet function of αSyn is proposed.
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Affiliation(s)
- Laura Acquasaliente
- Laboratory of Protein Chemistry and Molecular Hematology, Department of Pharmaceutical and Pharmacological Sciences, School of Medicine, University of Padua, via Marzolo, 5, 35131, Padua, Italy
| | - Giulia Pontarollo
- Laboratory of Protein Chemistry and Molecular Hematology, Department of Pharmaceutical and Pharmacological Sciences, School of Medicine, University of Padua, via Marzolo, 5, 35131, Padua, Italy.,Center for Thrombosis and Hemostasis (CTH) University Medical Center Mainz, Langenbeckstraße 1, 55131, Mainz, Germany
| | - Claudia Maria Radu
- Department of Women's & Children's Health, University of Padua, Padua, Italy.,Thrombotic and Hemorrhagic Diseases Unit, Department of Medicine, University of Padua, via Giustiniani, 2, 35128, Padua, Italy
| | - Daniele Peterle
- Laboratory of Protein Chemistry and Molecular Hematology, Department of Pharmaceutical and Pharmacological Sciences, School of Medicine, University of Padua, via Marzolo, 5, 35131, Padua, Italy.,Department of Chemistry and Chemical Biology, Northeastern University, 360 Huntington Ave. 02115, Boston, MA, USA
| | - Ilaria Artusi
- Laboratory of Protein Chemistry and Molecular Hematology, Department of Pharmaceutical and Pharmacological Sciences, School of Medicine, University of Padua, via Marzolo, 5, 35131, Padua, Italy
| | - Anna Pagotto
- Laboratory of Protein Chemistry and Molecular Hematology, Department of Pharmaceutical and Pharmacological Sciences, School of Medicine, University of Padua, via Marzolo, 5, 35131, Padua, Italy
| | - Federico Uliana
- Laboratory of Protein Chemistry and Molecular Hematology, Department of Pharmaceutical and Pharmacological Sciences, School of Medicine, University of Padua, via Marzolo, 5, 35131, Padua, Italy.,Institute of Molecular Systems Biology, ETH Zurich, 8093, Zurich, Switzerland
| | - Alessandro Negro
- Department of Biomedical Sciences, University of Padua, viale G. Colombo 3, 35100, Padua, Italy.
| | - Paolo Simioni
- Thrombotic and Hemorrhagic Diseases Unit, Department of Medicine, University of Padua, via Giustiniani, 2, 35128, Padua, Italy.
| | - Vincenzo De Filippis
- Laboratory of Protein Chemistry and Molecular Hematology, Department of Pharmaceutical and Pharmacological Sciences, School of Medicine, University of Padua, via Marzolo, 5, 35131, Padua, Italy. .,Biotechnology Center, CRIBI, University of Padua, Padua, Italy.
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Maners J, Gill D, Pankratz N, Laffan MA, Wolberg AS, de Maat MPM, Ligthart S, Tang W, Ward-Caviness CK, Fornage M, Debette S, Dichgans M, McKnight B, Boerwinkle E, Smith NL, Morrison AC, Dehghan A, de Vries PS. A Mendelian randomization of γ' and total fibrinogen levels in relation to venous thromboembolism and ischemic stroke. Blood 2020; 136:3062-3069. [PMID: 33367543 PMCID: PMC7770565 DOI: 10.1182/blood.2019004781] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 07/12/2020] [Indexed: 12/23/2022] Open
Abstract
Fibrinogen is a key component of the coagulation cascade, and variation in its circulating levels may contribute to thrombotic diseases, such as venous thromboembolism (VTE) and ischemic stroke. Gamma prime (γ') fibrinogen is an isoform of fibrinogen that has anticoagulant properties. We applied 2-sample Mendelian randomization (MR) to estimate the causal effect of total circulating fibrinogen and its isoform, γ' fibrinogen, on risk of VTE and ischemic stroke subtypes using summary statistics from genome-wide association studies. Genetic instruments for γ' fibrinogen and total fibrinogen were selected, and the inverse-variance weighted MR approach was used to estimate causal effects in the main analysis, complemented by sensitivity analyses that are more robust to the inclusion of pleiotropic variants, including MR-Egger, weighted median MR, and weighted mode MR. The main inverse-variance weighted MR estimates based on a combination of 16 genetic instruments for γ' fibrinogen and 75 genetic instruments for total fibrinogen indicated a protective effect of higher γ' fibrinogen and higher total fibrinogen on VTE risk. There was also a protective effect of higher γ' fibrinogen levels on cardioembolic and large artery stroke risk. Effect estimates were consistent across sensitivity analyses. Our results provide evidence to support effects of genetically determined γ' fibrinogen on VTE and ischemic stroke risk. Further research is needed to explore mechanisms underlying these effects and their clinical applications.
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Affiliation(s)
- Jillian Maners
- Human Genetics Center, Department of Epidemiology, Human Genetics, and Environmental Sciences, School of Public Health, The University of Texas Health Science Center at Houston, Houston, TX
| | - Dipender Gill
- Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, United Kingdom
| | - Nathan Pankratz
- Department of Laboratory Medicine and Pathology, School of Medicine, University of Minnesota, Minneapolis, MN
| | - Michael A Laffan
- Centre for Haematology, Imperial College London, London, United Kingdom
| | - Alisa S Wolberg
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC
| | | | - Symen Ligthart
- Department of Epidemiology, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Weihong Tang
- Division of Epidemiology and Community Health, University of Minnesota, Minneapolis, MN
| | - Cavin K Ward-Caviness
- National Health and Environmental Effects Laboratory, US Environmental Protection Agency, Chapel Hill, NC
| | - Myriam Fornage
- The Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center at Houston, Houston, TX
| | - Stephanie Debette
- Stroke Research Group, Division of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
- Department of Neurology, Institute for Neurodegenerative Disease, Bordeaux University Hospital, Bordeaux, France
| | - Martin Dichgans
- Institute for Stroke and Dementia Research, University Hospital, Ludwig-Maximilians-Universität, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Barbara McKnight
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX
| | - Eric Boerwinkle
- Human Genetics Center, Department of Epidemiology, Human Genetics, and Environmental Sciences, School of Public Health, The University of Texas Health Science Center at Houston, Houston, TX
- Department of Biostatistics, University of Washington, Seattle, WA
| | - Nicholas L Smith
- Kaiser Permanente Washington Research Institute, Kaiser Permanente Washington, Seattle, WA
- Department of Epidemiology, University of Washington, Seattle, WA
- Seattle Epidemiologic Research and Information Center, Office of Research and Development, Department of Veteran Affairs, Seattle, WA
| | - Alanna C Morrison
- Human Genetics Center, Department of Epidemiology, Human Genetics, and Environmental Sciences, School of Public Health, The University of Texas Health Science Center at Houston, Houston, TX
| | - Abbas Dehghan
- Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, United Kingdom
- Medical Research Council-Public Health England (MRC-PHE) Centre for Environment and Health, School of Public Health, Imperial College London, London, United Kingdom; and
- UK Dementia Research Institute, Imperial College London, London, United Kingdom
| | - Paul S de Vries
- Human Genetics Center, Department of Epidemiology, Human Genetics, and Environmental Sciences, School of Public Health, The University of Texas Health Science Center at Houston, Houston, TX
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5
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Farrell DH, Rick EA, Dewey EN, Schreiber MA, Rowell SE. γ' fibrinogen levels are associated with blood clot strength in traumatic brain injury patients. Am J Surg 2020; 220:459-463. [PMID: 31948701 PMCID: PMC7641475 DOI: 10.1016/j.amjsurg.2019.12.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 11/20/2019] [Accepted: 12/23/2019] [Indexed: 12/20/2022]
Abstract
BACKGROUND γ' fibrinogen is an alternatively-spliced fibrinogen variant that displays different coagulation parameters in vitro than the major form of fibrinogen. Purified γ' fibrinogen has slower clotting kinetics than unfractionated fibrinogen, but forms clots that are stronger and resistant to fibrinolysis. However, these properties have only been investigated in human populations in a limited number of studies. We therefore performed a retrospective analysis to test the hypothesis that γ' fibrinogen levels influence coagulation in vivo. METHODS In the present study, we utilized blood samples that were collected from traumatic brain injury patients to probe the relationship between γ' fibrinogen levels and traditional coagulation parameters. RESULTS The results show that the levels of γ' fibrinogen were inversely associated with clotting kinetics, indicated by a shortened INR. In addition, the levels of γ' fibrinogen were associated with stronger clots by thrombelastography. However, these changes were not associated with significant changes in hemorrhage progression. CONCLUSIONS These findings verify that γ' fibrinogen properties observed in purified systems result in similar properties in a clinical setting, and may affect coagulation.
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Affiliation(s)
- David H Farrell
- Division of Trauma, Critical Care and Acute Care Surgery, Department of Surgery, Oregon Health & Science University, Portland, OR, USA.
| | - Elizabeth A Rick
- Division of Trauma, Critical Care and Acute Care Surgery, Department of Surgery, Oregon Health & Science University, Portland, OR, USA
| | - Elizabeth N Dewey
- Division of Trauma, Critical Care and Acute Care Surgery, Department of Surgery, Oregon Health & Science University, Portland, OR, USA
| | - Martin A Schreiber
- Division of Trauma, Critical Care and Acute Care Surgery, Department of Surgery, Oregon Health & Science University, Portland, OR, USA
| | - Susan E Rowell
- Division of Trauma, Critical Care and Acute Care Surgery, Department of Surgery, Duke University School of Medicine, Durham, NC, USA
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Plasma-Based Proteomics Profiling of Patients with Hyperthyroidism after Antithyroid Treatment. Molecules 2020; 25:molecules25122831. [PMID: 32575434 PMCID: PMC7356574 DOI: 10.3390/molecules25122831] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 06/14/2020] [Accepted: 06/17/2020] [Indexed: 12/22/2022] Open
Abstract
Thyroid hormones critically modulate body homeostasis and haemostasis by regulating energy and metabolism. Previous studies have focused on individual pathways or proteins that are affected by increases in thyroid hormone levels, while an overall plasma proteomic signature of this increased level is lacking. Herein, an integrated untargeted proteomic approach with network analysis was used to identify changes in circulating proteins in the plasma proteome between hyperthyroid and euthyroid states. Plasma from 10 age-matched subjects at baseline (hyperthyroid) and post treatment with carbimazole (euthyroid) was compared by difference gel electrophoresis (DIGE) and matrix-assisted laser desorption/ionization time of flight (MALDI TOF) mass spectrometry (MS). A total of 20 proteins were identified with significant difference in abundance (analysis of variance (ANOVA) test, p ≤ 0.05; fold-change ≥ 1.5) between the two states (12 increased and 8 decreased in abundance in the hyperthyroid state). Twelve protein spots corresponding to ten unique proteins were significantly more abundant in the hyperthyroid state compared with the euthyroid state. These increased proteins were haptoglobin (HP), hemopexin (HPX), clusterin (CLU), apolipoprotein L1 (APOL1), alpha-1-B glycoprotein (A1BG), fibrinogen gamma chain (FGG), Ig alpha-1 chain C region (IGHA1), complement C6 (C6), leucine rich alpha 2 glycoprotein (LRG1), and carboxypeptidase N catalytic chain (CPN1). Eight protein spots corresponding to six unique proteins were significantly decreased in abundance in the hyperthyroid samples compared with euthyroid samples. These decreased proteins were apolipoprotein A1 (APOA1), inter-alpha-trypsin inhibitor heavy chain 4 (ITIH4), plasminogen (PLG), alpha-1 antitrypsin (SERPINA1), fibrinogen beta chain (FGB), and complement C1r subcomponent (C1R). The differentially abundant proteins were investigated by ingenuity pathway analysis (IPA). The network pathway identified related to infectious disease, inflammatory disease, organismal injury and abnormalities, and the connectivity map focused around two central nodes, namely the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and p38 mitogen-activated protein kinase (MAPK) pathways. The plasma proteome of patients with hyperthyroidism revealed differences in the abundance of proteins involved in acute phase response signaling, and development of a hypercoagulable and hypofibrinolytic state. Our findings enhance our existing knowledge of the altered proteins and associated biochemical pathways in hyperthyroidism.
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Querino Lima Afonso M, da Fonseca NJ, de Oliveira LC, Lobo FP, Bleicher L. Coevolved Positions Represent Key Functional Properties in the Trypsin-Like Serine Proteases Protein Family. J Chem Inf Model 2020; 60:1060-1068. [DOI: 10.1021/acs.jcim.9b00903] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Marcelo Querino Lima Afonso
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Pres. Antônio Carlos, 6627 - Pampulha, Belo Horizonte, Minas Gerais, Brazil 31270-901
| | - Neli J. da Fonseca
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Pres. Antônio Carlos, 6627 - Pampulha, Belo Horizonte, Minas Gerais, Brazil 31270-901
| | - Lucas Carrijo de Oliveira
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Pres. Antônio Carlos, 6627 - Pampulha, Belo Horizonte, Minas Gerais, Brazil 31270-901
| | - Francisco Pereira Lobo
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Pres. Antônio Carlos, 6627 - Pampulha, Belo Horizonte, Minas Gerais, Brazil 31270-901
| | - Lucas Bleicher
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Pres. Antônio Carlos, 6627 - Pampulha, Belo Horizonte, Minas Gerais, Brazil 31270-901
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Cantero M, Rojas H, Anglés-Cano E, Marchi R. Fibrin γ/γ' influences the secretion of fibrinolytic components and clot structure. BMC Mol Cell Biol 2019; 20:47. [PMID: 31675913 PMCID: PMC6824120 DOI: 10.1186/s12860-019-0233-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 10/15/2019] [Indexed: 11/10/2022] Open
Abstract
Background In healthy subjects fibrinogen γ/γ‘ circulates at 8–15% of the total plasma fibrinogen concentration. Elevated levels of this variant have been associated with arterial thrombosis, and its diminution with venous thrombosis. The aims of the present work were to analyze the structure of the fibrin network formed on the top of human dermal microvascular endothelial cells (HMEC-1) at different fibrinogen γ/γ‘ concentrations, as well as its influence on the secretion of fibrinolytic components. The kinetics of fibrin polymerization on top of HMEC-1 cells with 3, 10, and 30% fibrinogen γ/γ‘ was followed at 350 nm. The secretion of urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitor type 1 (PAI 1) by HMEC-1 were measured in the supernatant and cell lysates, after incubation with 1 nM thrombin, fibrin with 3, and 30% fibrinogen γ/γ‘, using commercial kits. The influence of fibrinogen γ/γ‘ on fibrin structure on the surface of the HMEC-1 was followed with laser scanning confocal microscopy (LSCM). Results The kinetics of fibrin formation on HMEC-1 with 3 and 10% fibrinogen γ/γ‘ were similar. However, with 30% fibrinogen γ/γ‘ both the slope and final turbity were approximately 50% less. The LSCM images showed the dramatic effects of increasing fibrinogen γ/γ‘ from 3 to 30%. The uPA and PAI 1 concentrations in culture supernatants HMEC-1 cells treated with thrombin or 30% γ/γ‘ fibrin were two-fold increased as compared to basal culture supernatants and 3% γ/γ‘ fibrin-treated HMEC-1. In all stimulatory conditions the intracellular concentration of uPA was higher than in supernatants. In contrast, the intracellular PAI 1 concentration was decreased as compared to that measured in the supernatant, including the basal condition. Conclusion A concentration of 30% fibrin γ/γ‘ alter drastically fibrin structure on the cell surface and affects the secretion of uPA and PAI 1 through its capacity to bind thrombin.
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Affiliation(s)
- Miriam Cantero
- Departamento de Bioquímica, Universidad de Córdoba, Córdoba, Colombia.,Centro de Medicina Experimental, Laboratorio Biología del Desarrollo de la Hemostasia, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela
| | - Héctor Rojas
- Instituto de Inmunología, Universidad Central de Venezuela, Caracas, Venezuela
| | - Eduardo Anglés-Cano
- Université de Paris, Innovative Therapies in Haemostasis, INSERM, F-75006, Paris, France
| | - Rita Marchi
- Centro de Medicina Experimental, Laboratorio Biología del Desarrollo de la Hemostasia, Instituto Venezolano de Investigaciones Científicas, Caracas, Venezuela.
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9
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Chen F, Jiang H, Chen W, Huang G. Interaction of the synthetic antithrombotic peptide P10 with thrombin: a spectroscopy study. RSC Adv 2019; 9:18498-18505. [PMID: 35515240 PMCID: PMC9064813 DOI: 10.1039/c9ra02994j] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Accepted: 05/29/2019] [Indexed: 11/21/2022] Open
Abstract
Thrombin is a critical serine protease in the coagulation system and is widely used as a target protein for antithrombotics. Spectroscopic analysis is a simple and effective method that is used to study the interaction between small molecules and proteins. In this study, the interactions of a potential antithrombotic peptide AGFAGDDAPR (P10) with thrombin were investigated by fluorescence spectroscopy, UV-vis spectroscopy, circular dichroism, Fourier-transform infrared spectroscopy and Raman spectroscopy, respectively. The results showed that the peptide P10 bonded to thrombin via hydrogen bonding and van der Waals forces, resulting in fluorescence quenching. And, the secondary structure of thrombin changed, the β-sheet decreased, and the random coil increased. The peptide P10 bonded to proline and lysine, and changed the space structure of thrombin, resulting in inhibition of thrombin activity. The results contributed to exploration of the mechanism of this potential antithrombotic drug interaction with thrombin in order to provide a preliminary understanding of the pharmacodynamic properties of P10.
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Affiliation(s)
- Fangyuan Chen
- Key Lab of Marine Food Quality and Hazard Controlling Technology of Zhejiang Province, College of Life Sciences, China Jiliang University Hangzhou China +86 571 8687 5628
| | - Han Jiang
- Key Lab of Marine Food Quality and Hazard Controlling Technology of Zhejiang Province, College of Life Sciences, China Jiliang University Hangzhou China +86 571 8687 5628
| | - Wenwei Chen
- Key Lab of Marine Food Quality and Hazard Controlling Technology of Zhejiang Province, College of Life Sciences, China Jiliang University Hangzhou China +86 571 8687 5628
| | - Guangrong Huang
- Key Lab of Marine Food Quality and Hazard Controlling Technology of Zhejiang Province, College of Life Sciences, China Jiliang University Hangzhou China +86 571 8687 5628
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10
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Billur R, Sabo TM, Maurer MC. Thrombin Exosite Maturation and Ligand Binding at ABE II Help Stabilize PAR-Binding Competent Conformation at ABE I. Biochemistry 2019; 58:1048-1060. [PMID: 30672691 DOI: 10.1021/acs.biochem.8b00943] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Thrombin, derived from zymogen prothrombin (ProT), is a serine protease involved in procoagulation, anticoagulation, and platelet activation. Thrombin's actions are regulated through anion-binding exosites I and II (ABE I and ABE II) that undergo maturation during activation. Mature ABEs can utilize exosite-based communication to fulfill thrombin functions. However, the conformational basis behind such long-range communication and the resultant ligand binding affinities are not well understood. Protease activated receptors (PARs), involved in platelet activation and aggregation, are known to target thrombin ABE I. Unexpectedly, PAR3 (44-56) can already bind to pro-ABE I of ProT. Nuclear magnetic resonance (NMR) ligand-enzyme titrations were used to characterize how individual PAR1 (49-62) residues interact with pro-ABE I and mature ABE I. 1D proton line broadening studies demonstrated that binding affinities for native PAR1P (49-62, P54) and for the weak binding variant PAR1G (49-62, P54G) increased as ProT was converted to mature thrombin. 1H,15N-HSQC titrations revealed that PAR1G residues K51, E53, F55, D58, and E60 exhibited less affinity to pro-ABE I than comparable residues in PAR3G (44-56, P51G). Individual PAR1G residues then displayed tighter binding upon exosite maturation. Long-range communication between thrombin exosites was examined by saturating ABE II with phosphorylated GpIbα (269-282, 3Yp) and monitoring the binding of PAR1 and PAR3 peptides to ABE I. Individual PAR residues exhibited increased affinities in this dual-ligand environment supporting the presence of interexosite allostery. Exosite maturation and beneficial long-range allostery are proposed to help stabilize an ABE I conformation that can effectively bind PAR ligands.
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Affiliation(s)
- Ramya Billur
- Department of Chemistry , University of Louisville , Louisville , Kentucky 40292 , United States
| | - T Michael Sabo
- Department of Medicine, James Graham Brown Cancer Center , University of Louisville , Louisville , Kentucky 40202 , United States
| | - Muriel C Maurer
- Department of Chemistry , University of Louisville , Louisville , Kentucky 40292 , United States
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11
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De Filippis V, Acquasaliente L, Pontarollo G, Peterle D. Noncoded amino acids in protein engineering: Structure-activity relationship studies of hirudin-thrombin interaction. Biotechnol Appl Biochem 2018; 65:69-80. [DOI: 10.1002/bab.1632] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Accepted: 12/06/2017] [Indexed: 11/12/2022]
Affiliation(s)
- Vincenzo De Filippis
- Laboratory of Protein Chemistry; Department of Pharmaceutical & Pharmacological Sciences; University of Padua; Padua Italy
| | - Laura Acquasaliente
- Laboratory of Protein Chemistry; Department of Pharmaceutical & Pharmacological Sciences; University of Padua; Padua Italy
| | - Giulia Pontarollo
- Laboratory of Protein Chemistry; Department of Pharmaceutical & Pharmacological Sciences; University of Padua; Padua Italy
| | - Daniele Peterle
- Laboratory of Protein Chemistry; Department of Pharmaceutical & Pharmacological Sciences; University of Padua; Padua Italy
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12
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Pontarollo G, Acquasaliente L, Peterle D, Frasson R, Artusi I, De Filippis V. Non-canonical proteolytic activation of human prothrombin by subtilisin from Bacillus subtilis may shift the procoagulant-anticoagulant equilibrium toward thrombosis. J Biol Chem 2017; 292:15161-15179. [PMID: 28684417 DOI: 10.1074/jbc.m117.795245] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Revised: 06/28/2017] [Indexed: 12/26/2022] Open
Abstract
Blood coagulation is a finely regulated physiological process culminating with the factor Xa (FXa)-mediated conversion of the prothrombin (ProT) zymogen to active α-thrombin (αT). In the prothrombinase complex on the platelet surface, FXa cleaves ProT at Arg-271, generating the inactive precursor prethrombin-2 (Pre2), which is further attacked at Arg-320-Ile-321 to yield mature αT. Whereas the mechanism of physiological ProT activation has been elucidated in great detail, little is known about the role of bacterial proteases, possibly released in the bloodstream during infection, in inducing blood coagulation by direct proteolytic ProT activation. This knowledge gap is particularly concerning, as bacterial infections are frequently complicated by severe coagulopathies. Here, we show that addition of subtilisin (50 nm to 2 μm), a serine protease secreted by the non-pathogenic bacterium Bacillus subtilis, induces plasma clotting by proteolytically converting ProT into active σPre2, a nicked Pre2 derivative with a single cleaved Ala-470-Asn-471 bond. Notably, we found that this non-canonical cleavage at Ala-470-Asn-471 is instrumental for the onset of catalysis in σPre2, which was, however, reduced about 100-200-fold compared with αT. Of note, σPre2 could generate fibrin clots from fibrinogen, either in solution or in blood plasma, and could aggregate human platelets, either isolated or in whole blood. Our findings demonstrate that alternative cleavage of ProT by proteases, even by those secreted by non-virulent bacteria such as B. subtilis, can shift the delicate procoagulant-anticoagulant equilibrium toward thrombosis.
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Affiliation(s)
- Giulia Pontarollo
- From the Department of Pharmaceutical and Pharmacological Sciences, University of Padua, via Marzolo 5, Padua 35131, Italy
| | - Laura Acquasaliente
- From the Department of Pharmaceutical and Pharmacological Sciences, University of Padua, via Marzolo 5, Padua 35131, Italy
| | - Daniele Peterle
- From the Department of Pharmaceutical and Pharmacological Sciences, University of Padua, via Marzolo 5, Padua 35131, Italy
| | - Roberta Frasson
- From the Department of Pharmaceutical and Pharmacological Sciences, University of Padua, via Marzolo 5, Padua 35131, Italy
| | - Ilaria Artusi
- From the Department of Pharmaceutical and Pharmacological Sciences, University of Padua, via Marzolo 5, Padua 35131, Italy
| | - Vincenzo De Filippis
- From the Department of Pharmaceutical and Pharmacological Sciences, University of Padua, via Marzolo 5, Padua 35131, Italy
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13
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Molecular mapping of α-thrombin (αT)/β2-glycoprotein I (β2GpI) interaction reveals how β2GpI affects αT functions. Biochem J 2016; 473:4629-4650. [PMID: 27760842 DOI: 10.1042/bcj20160603] [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: 06/22/2016] [Revised: 09/07/2016] [Accepted: 10/14/2016] [Indexed: 01/15/2023]
Abstract
β2-Glycoprotein I (β2GpI) is the major autoantigen in the antiphospholipid syndrome, a thrombotic autoimmune disease. Nonetheless, the physiological role of β2GpI is still unclear. In a recent work, we have shown that β2GpI selectively inhibits the procoagulant functions of human α-thrombin (αT; i.e. prolongs fibrin clotting time, tc, and inhibits αT-induced platelet aggregation) without affecting the unique anticoagulant activity of the protease, i.e. the proteolytic generation of the anticoagulant protein C (PC) from the PC zymogen, which interacts with αT exclusively at the protease catalytic site. Here, we used several different biochemical/biophysical techniques and molecular probes for mapping the binding sites in the αT-β2GpI complex. Our results indicate that αT exploits the highly electropositive exosite-II, which is also responsible for anchoring αT on the platelet GpIbα (platelet receptor glycoprotein Ibα) receptor, for binding to a continuous negative region on β2GpI structure, spanning domain IV and (part of) domain V, whereas the protease active site and exosite-I (i.e. the fibrinogen-binding site) remain accessible for substrate/ligand binding. Furthermore, we provided evidence that the apparent increase in tc, previously observed with β2GpI, is more likely caused by alteration in the ensuing fibrin structure rather than by the inhibition of fibrinogen hydrolysis. Finally, we produced a theoretical docking model of αT-β2GpI interaction, which was in agreement with the experimental results. Altogether, these findings help to understand how β2GpI affects αT interactions and suggest that β2GpI may function as a scavenger of αT for binding to the GpIbα receptor, thus impairing platelet aggregation while enabling normal cleavage of fibrinogen and PC.
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14
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Liu X, Wang C, Ding X, Liu X, Li Q, Kong Y. A novel selective inhibitor to thrombin-induced platelet aggregation purified from the leech Whitmania pigra. Biochem Biophys Res Commun 2016; 473:349-354. [DOI: 10.1016/j.bbrc.2016.03.117] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Accepted: 03/23/2016] [Indexed: 11/26/2022]
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15
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Sokolov AV, Acquasaliente L, Kostevich VA, Frasson R, Zakharova ET, Pontarollo G, Vasilyev VB, De Filippis V. Thrombin inhibits the anti-myeloperoxidase and ferroxidase functions of ceruloplasmin: relevance in rheumatoid arthritis. Free Radic Biol Med 2015; 86:279-94. [PMID: 26001728 DOI: 10.1016/j.freeradbiomed.2015.05.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 04/24/2015] [Accepted: 05/12/2015] [Indexed: 01/29/2023]
Abstract
Human ceruloplasmin (CP) is a multifunctional copper-binding protein produced in the liver. CP oxidizes Fe(2+) to Fe(3+), decreasing the concentration of Fe(2+) available for generating harmful oxidant species. CP is also a potent inhibitor of leukocyte myeloperoxidase (MPO) (Kd=130nM), a major source of oxidants in vivo. Rheumatoid arthritis (RA) is an inflammatory autoimmune disease affecting flexible joints and characterized by activation of both inflammatory and coagulation processes. Indeed, the levels of CP, MPO, and thrombin are markedly increased in the synovial fluid of RA patients. Here we show that thrombin cleaves CP in vitro at (481)Arg-Ser(482) and (887)Lys-Val(888) bonds, generating a nicked species that retains the native-like fold and the ferroxidase activity of the intact protein, whereas the MPO inhibitory function of CP is abrogated. Analysis of the synovial fluid of 24 RA patients reveals that CP is proteolytically degraded to a variable extent, with a fragmentation pattern similar to that observed with thrombin in vitro, and that proteolysis is blocked by hirudin, a highly potent and specific thrombin inhibitor. Using independent biophysical techniques, we show that thrombin has intrinsic affinity for CP (Kd=60-270nM), independent of proteolysis, and inhibits CP ferroxidase activity (KI=220±20nM). Mapping of thrombin binding sites with specific exosite-directed ligands (i.e., hirugen, fibrinogen γ'-peptide) and thrombin analogues having the exosites variably compromised (i.e., prothrombin, prethrombin-2, βT-thrombin) reveals that the positively charged exosite-II of thrombin binds to the negatively charged upper region of CP, while the protease active site and exosite-I remain accessible. These results suggest that thrombin can exacerbate inflammation in RA by impairing the MPO inhibitory function of CP via proteolysis and by competitively inhibiting CP ferroxidase activity. Notably, local administration of hirudin, a highly potent and specifc thrombin inhibitor, reduces the concentration of active MPO in the synovial fluid of RA patients and has a beneficial effect on the clinical symptoms of the disease.
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Affiliation(s)
- Alexej V Sokolov
- Institute for Experimental Medicine, Pavlov str., 12, Saint Petersburg, 197376 Russia; State University of Saint Petersburg, University Embankment, 4-7, Saint Petersburg, 199034 Russia
| | - Laura Acquasaliente
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, via Marzolo, 5, Padua, 35131 Italy
| | - Valeria A Kostevich
- Institute for Experimental Medicine, Pavlov str., 12, Saint Petersburg, 197376 Russia
| | - Roberta Frasson
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, via Marzolo, 5, Padua, 35131 Italy
| | - Elena T Zakharova
- Institute for Experimental Medicine, Pavlov str., 12, Saint Petersburg, 197376 Russia
| | - Giulia Pontarollo
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, via Marzolo, 5, Padua, 35131 Italy
| | - Vadim B Vasilyev
- Institute for Experimental Medicine, Pavlov str., 12, Saint Petersburg, 197376 Russia; State University of Saint Petersburg, University Embankment, 4-7, Saint Petersburg, 199034 Russia
| | - Vincenzo De Filippis
- Department of Pharmaceutical and Pharmacological Sciences, University of Padua, via Marzolo, 5, Padua, 35131 Italy.
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16
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Boknäs N, Faxälv L, Sanchez Centellas D, Wallstedt M, Ramström S, Grenegård M, Lindahl TL. Thrombin-induced platelet activation via PAR4: pivotal role for exosite II. Thromb Haemost 2014; 112:558-65. [PMID: 24990072 DOI: 10.1160/th13-12-1013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 04/20/2014] [Indexed: 01/22/2023]
Abstract
Thrombin-induced platelet activation via PAR1 and PAR4 is an important event in haemostasis. Although the underlying mechanisms responsible for ensuring efficient PAR1 activation by thrombin have been extensively studied, the potential involvement of recognitions sites outside the active site of the protease in thrombin-induced PAR4 activation is largely unknown. In this study, we developed a new assay to assess the importance of exosite I and II for PAR4 activation with α - and γ-thrombin. Surprisingly, we found that exosite II is critical for activation of PAR4. We also show that this dependency on exosite II likely represents a new mechanism, as it is unaffected by blockage of the previously known interaction between thrombin and glycoprotein Ibα.
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Affiliation(s)
| | | | | | | | | | | | - T L Lindahl
- Tomas Lindahl, Department of Clinical and Experimental Medicine, Linköping University, SE-51885 Linköping, Sweden, Tel.: +46 101033227, Fax: +46 101033240, E-mail:
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17
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Fibrinogen γ' increases the sensitivity to activated protein C in normal and factor V Leiden plasma. Blood 2014; 124:1531-8. [PMID: 24951429 DOI: 10.1182/blood-2014-02-554055] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Activated protein C (APC) resistance, often associated with the factor V (FV) Leiden mutation, is the most common risk factor for venous thrombosis. We observed increased APC resistance in carriers of fibrinogen γ gene (FGG) haplotype 2, which is associated with reduced levels of the alternatively spliced fibrinogen γ' chain. This finding prompted us to study the effects of fibrinogen and its γ' chain on APC resistance. Fibrinogen, and particularly the γA/γ' isoform, improved the response of plasma to added APC in the thrombin generation-based assay. Similarly, a synthetic peptide mimicking the C-terminus of the fibrinogen γ' chain, which binds thrombin and inhibits its activities, greatly increased the APC sensitivity of normal and FV Leiden plasma, likely due to its ability to inhibit thrombin-mediated activation of FV and FVIII. Although the fibrinogen γ' peptide also inhibited protein C activation by the thrombin/thrombomodulin complex, it still increased the sensitivity of plasma to endogenously formed APC when thrombin generation was measured in the presence of soluble thrombomodulin. We conclude that fibrinogen, and particularly fibrinogen γ', increases plasma APC sensitivity. The fibrinogen γ' peptide might form the basis for pharmacologic interventions to counteract APC resistance.
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18
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Lechtenberg BC, Freund SMV, Huntington JA. GpIbα interacts exclusively with exosite II of thrombin. J Mol Biol 2013; 426:881-93. [PMID: 24316004 PMCID: PMC3919161 DOI: 10.1016/j.jmb.2013.11.027] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Revised: 11/21/2013] [Accepted: 11/23/2013] [Indexed: 11/09/2022]
Abstract
Activation of platelets by the serine protease thrombin is a critical event in haemostasis. This process involves the binding of thrombin to glycoprotein Ibα (GpIbα) and cleavage of protease-activated receptors (PARs). The N-terminal extracellular domain of GpIbα contains an acidic peptide stretch that has been identified as the main thrombin binding site, and both anion binding exosites of thrombin have been implicated in GpIbα binding, but it remains unclear how they are involved. This issue is of critical importance for the mechanism of platelet activation by thrombin. If both exosites bind to GpIbα, thrombin could potentially act as a platelet adhesion molecule or receptor dimerisation trigger. Alternatively, if only a single site is involved, GpIbα may serve as a cofactor for PAR-1 activation by thrombin. To determine the involvement of thrombin's two exosites in GpIbα binding, we employed the complementary methods of mutational analysis, binding studies, X-ray crystallography and NMR spectroscopy. Our results indicate that the peptide corresponding to the C-terminal portion of GpIbα and the entire extracellular domain bind exclusively to thrombin's exosite II. The interaction of thrombin with GpIbα thus serves to recruit thrombin activity to the platelet surface while leaving exosite I free for PAR-1 recognition. We analysed interactions of the platelet receptor GpIbα with thrombin using three complementary methods. GpIbα exclusively binds to exosite II of thrombin. Exosite I remains available for binding to other ligands. GpIbα recruits thrombin to the platelet membrane as a cofactor for PAR-1 cleavage.
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Affiliation(s)
- Bernhard C Lechtenberg
- Department of Haematology, Cambridge Institute for Medical Research, University of Cambridge, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Stefan M V Freund
- MRC Laboratory for Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - James A Huntington
- Department of Haematology, Cambridge Institute for Medical Research, University of Cambridge, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, United Kingdom.
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19
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Omarova F, Uitte De Willige S, Ariëns RAS, Rosing J, Bertina RM, Castoldi E. Inhibition of thrombin-mediated factor V activation contributes to the anticoagulant activity of fibrinogen γ'. J Thromb Haemost 2013; 11:1669-78. [PMID: 23848367 DOI: 10.1111/jth.12354] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Indexed: 08/31/2023]
Abstract
BACKGROUND Besides its role in blood clotting, fibrinogen exerts a poorly understood anticoagulant function by binding thrombin and modulating its activity. In particular, the γA/γ' fibrinogen isoform binds with high affinity to thrombin exosite II through the anionic carboxyl-terminal end of the γ' chain. This interaction down-regulates thrombin-mediated factor VIII (FVIII) activation, but its effect on FV activation is unknown. OBJECTIVES To investigate the overall anticoagulant activity of fibrinogen and particularly of fibrinogen γ' in plasma, and to verify whether the fibrinogen γ' carboxyl-terminal peptide affects thrombin-mediated FV activation. METHODS Thrombin generation was measured by calibrated automated thrombography in whole and defibrinated plasma and in plasma supplemented with the (sulfated) fibrinogen γ' carboxyl-terminal peptide (0-500 μmol L(-1) ). The effect of the peptide on thrombin-mediated FV activation was studied in model systems and in plasma. RESULTS Total fibrinogen prolonged the lag time of thrombin generation at low tissue factor (TF) concentrations. The fibrinogen γ' peptide dose-dependently prolonged the lag time and decreased the peak height of thrombin generation at low TF, whereas a scrambled control peptide was ineffective. These effects persisted in the presence of an anti-FVIII antibody, suggesting that the peptide may also inhibit thrombin-mediated activation of FV. This was confirmed in model systems and in plasma. CONCLUSIONS Total fibrinogen and the fibrinogen γ' peptide have an overall anticoagulant effect on thrombin generation determined at low TF. Inhibition of thrombin-mediated FV activation by the fibrinogen γ' peptide is a novel mechanism of the anticoagulant activity of fibrinogen γ'.
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Affiliation(s)
- F Omarova
- Department of Biochemistry, Maastricht University, Maastricht, the Netherlands
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20
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Gamma prime fibrinogen and childhood obesity: ready for prime time? J Pediatr 2013; 163:315-6. [PMID: 23528256 DOI: 10.1016/j.jpeds.2013.02.034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2013] [Accepted: 02/13/2013] [Indexed: 11/24/2022]
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21
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Pozzi N, Acquasaliente L, Frasson R, Cristiani A, Moro S, Banzato A, Pengo V, Scaglione GL, Arcovito A, De Cristofaro R, De Filippis V. β2 -Glycoprotein I binds to thrombin and selectively inhibits the enzyme procoagulant functions. J Thromb Haemost 2013; 11:1093-102. [PMID: 23578283 DOI: 10.1111/jth.12238] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Indexed: 08/31/2023]
Abstract
BACKGROUND This work was aimed at characterizing the interaction of β(2)-glycoprotein I (β(2)GPI), an abundant plasma protein of unknown function, with human thrombin, the final effector protease in the coagulation cascade. METHODS The β(2)GPI-thrombin interaction was studied by surface plasmon resonance (SPR), fluorescence, and molecular modeling. The effect of β(2)GPI on the procoagulant (fibrin generation and platelet aggregation) and anticoagulant (protein C activation) functions of thrombin were investigated with turbidimetric, immunocytofluorimetric and enzymatic assays. RESULTS SPR and fluorescence data indicated that β(2)GPI tightly bound thrombin (K(d) = 34 nM) by interacting with both protease exosites, while leaving the active site accessible. This picture is fully consistent with the theoretical model of the β(2)GPI-thrombin complex. In particular, blockage of thrombin exosites with binders specific for exosite-1 (hirugen and HD1 aptamer) or exosite-2 (fibrinogen γ'-peptide and HD22 aptamer) impaired the β2 GPI-thrombin interaction. Identical results were obtained with thrombin mutants having one of the two exosites selectively compromised by mutation (Arg73Ala and Arg101Ala). Fluorescence measurements indicated that β(2)GPI did not affect the affinity of the enzyme for active site inhibitors, such as p-aminobenzamidine and the hirudin(1-47) domain, in agreement with the structural model. β(2)GPI dose-dependently prolonged the thrombin clotting time and ecarin clotting time in β(2)GPI-deficient plasma. β(2)GPI inhibited thrombin-induced platelet aggregation (IC50 = 0.36 μM) by impairing thrombin cleavage of protease-activated receptor 1 (PAR1) (IC50 = 0.32 μM), both on gel-filtered platelets and in whole blood. Strikingly, β(2) GPI did not affect thrombin-mediated generation of the anticoagulant protein C. CONCLUSIONS β(2) GPI functions as a physiologic anticoagulant by inhibiting the key procoagulant activities of thrombin without affecting its unique anticoagulant function.
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Affiliation(s)
- N Pozzi
- Laboratory of Protein Chemistry, School of Medicine, University of Padua, Padova, Italy
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22
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Malovichko MV, Sabo TM, Maurer MC. Ligand binding to anion-binding exosites regulates conformational properties of thrombin. J Biol Chem 2013; 288:8667-8678. [PMID: 23378535 DOI: 10.1074/jbc.m112.410829] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Thrombin participates in coagulation, anticoagulation, and initiation of platelet activation. To fulfill its diverse roles and maintain hemostasis, this serine protease is regulated via the extended active site region and anion-binding exosites (ABEs) I and II. For the current project, amide proton hydrogen-deuterium exchange coupled with MALDI-TOF mass spectrometry was used to characterize ligand binding to individual exosites and to investigate the presence of exosite-active site and exosite-exosite interactions. PAR3(44-56) and PAR1(49-62) were observed to bind to thrombin ABE I and then to exhibit long range effects over to ABE II. By contrast, Hirudin(54-65) focused more on ABE I and did not transmit influences over to ABE II. Although these three ligands were each directed to ABE I, they did not promote the same conformational consequences. D-Phe-Pro-Arg-chloromethyl ketone inhibition at the thrombin active site led to further local and long range consequences to thrombin-ABE I ligand complexes with the autolysis loop often most affected. When Hirudin(54-65) was bound to ABE I, it was still possible to bind GpIbα(269-286) or fibrinogen γ'(410-427) to ABE II. Each ligand exerted its predominant influences on thrombin and also allowed interexosite communication. The results obtained support the proposal that thrombin is a highly dynamic protein. The transmission of ligand-specific local and long range conformational events is proposed to help regulate this multifunctional enzyme.
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Affiliation(s)
| | - T Michael Sabo
- Chemistry Department, University of Louisville, Louisville, Kentucky 40292
| | - Muriel C Maurer
- Chemistry Department, University of Louisville, Louisville, Kentucky 40292.
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23
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Alexander KS, Fried MG, Farrell DH. Role of electrostatic interactions in binding of thrombin to the fibrinogen γ' chain. Biochemistry 2012; 51:3445-50. [PMID: 22439748 DOI: 10.1021/bi2016519] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Thrombin binds to the highly anionic fibrinogen γ' chain through anion-binding exosite II. This binding profoundly alters thrombin's ability to cleave substrates, including fibrinogen, factor VIII, and PAR1. However, it is unknown whether this interaction is due mainly to general electrostatic complementarity between the γ' chain and exosite II or if there are critical charged γ' chain residues involved. We therefore systematically determined the contribution of negatively charged amino acids in the γ' chain, both individually and collectively, to thrombin binding affinity. Surface plasmon resonance binding experiments were performed using immobilized γ' chain peptides with charged-to-uncharged amino acid substitutions, i.e., Asp to Asn, Glu to Gln, and pTyr to Tyr. Individually, the substitution of uncharged for charged amino acids resulted in only minor changes in binding affinity, with a maximal change in K(d) from 0.440 to 0.705 μM for the Asp419Asn substitution. However, substitution of all three charged amino acids in a conserved β-turn that is predicted to contact thrombin, pTyr418Tyr, Asp419Asn, and pTyr422Tyr, resulted in the loss of measurable binding, as did substitution of all the flanking charged amino acids. In addition, the binding of the γ' chain to thrombin was weakened in a dose-dependent manner with increasing NaCl concentration, resulting in a net loss of three or four ion pairs between thrombin and the γ' chain. Therefore, although each of the individual charges in the γ' chain contributes only incrementally to the overall binding affinity, the ensemble of the combined charges plays a profound role in the thrombin-γ' chain interactions.
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Affiliation(s)
- Kristine S Alexander
- Department of Molecular and Medical Genetics, Oregon Health & Science University , Portland, OR 97239-3098, USA
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24
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Oxidation of Met1606 in von Willebrand factor is a risk factor for thrombotic and septic complications in chronic renal failure. Biochem J 2012; 442:423-32. [PMID: 22091998 DOI: 10.1042/bj20111798] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
CKD (chronic kidney disease) is a life-threatening pathology, often requiring HD (haemodialysis) and characterized by high OS (oxidative stress), inflammation and perturbation of vascular endothelium. HD patients have increased levels of vWF (von Willebrand factor), a large protein (~240 kDa) released as UL-vWF (ultra large-vWF polymers, molecular mass ~20000-50000 kDa) from vascular endothelial cells and megakaryocytes, and responsible for the initiation of primary haemostasis. The pro-haemostatic potential of vWF increases with its length, which is proteolytically regulated by ADAMTS-13 (a disintegrin and metalloproteinase with thrombospondin motifs 13), a zinc-protease cleaving vWF at the single Tyr1605-Met1606 bond, and by LSPs (leucocyte serine proteases), released by activated PMNs (polymorphonuclear cells) during bacterial infections. Previous studies have shown that in vitro oxidation of Met1606 hinders vWF cleavage by ADAMTS-13, resulting in the accumulation of UL-vWF that are not only more pro-thrombotic than shorter vWF oligomers, but also more efficient in binding to bacterial adhesins during sepsis. Notably, HD patients have increased risk of developing dramatic cardiovascular and septic complications, whose underlying mechanisms are largely unknown. In the present study, we first purified vWF from HD patients and then chemically characterized its oxidative state. Interestingly, HD-vWF contains high carbonyl levels and increased proportion of UL-vWF polymers that are also more resistant to ADAMTS-13. Using TMS (targeted MS) techniques, we estimated that HD-vWF contains >10% of Met1606 in the sulfoxide form. We conclude that oxidation of Met1606, impairing ADAMTS-13 cleavage, results in the accumulation of UL-vWF polymers, which recruit and activate platelets more efficiently and bind more tightly to bacterial adhesins, thus contributing to the development of thrombotic and septic complications in CKD.
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van den Herik EG, Cheung EYL, de Lau LML, den Hertog HM, Leebeek FWG, Dippel DWJ, Koudstaal PJ, de Maat MPM. Fibrinogen γ' levels in patients with intracerebral hemorrhage. Thromb Res 2011; 129:807-9. [PMID: 21917300 DOI: 10.1016/j.thromres.2011.08.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2011] [Revised: 08/07/2011] [Accepted: 08/17/2011] [Indexed: 11/27/2022]
Abstract
BACKGROUND The fibrinogen γ' variant (γ') has both antithrombotic and prothrombotic properties when compared to normal fibrinogen. It may therefore be of relevance in intracerebral hemorrhage and intraventricular extension of the bleeding. OBJECTIVE To study the role of γ' in intracerebral hemorrhage, and in intraventricular extension of the hemorrhage. PATIENTS/METHODS We performed a case-control study in 156 controls and 55 patients with intracerebral hemorrhage, with and without intraventricular extension. Levels of fibrinogen γ' and the γ'/total fibrinogen ratio were measured in all participants. RESULTS Levels of γ' were increased in patients with intracerebral hemorrhage when compared with controls (0.40 vs 0.32g/l, p<0.001). The γ'/total fibrinogen ratio was similar in patients and controls (0.092 vs 0.096 p=0.42). There was evidence for an unfavorable outcome in patients with fibrinogen levels in the highest tertile compared with the lowest tertile (OR 4.0, 95%CI 1.1-15.2), and a nonsignificant trend toward unfavorable outcome with higher levels of γ' (p-value for trend=0.06). CONCLUSIONS Our study shows that absolute levels of fibrinogen γ' are increased in patients with intracerebral hemorrhage, but relative levels are similar in patients and controls, suggesting that the absolute rise in γ' is an acute phase response.
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Affiliation(s)
- E G van den Herik
- Department of Neurology, Erasmus MC University Medical Center, Rotterdam, The Netherlands.
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Cilia La Corte AL, Philippou H, Ariëns RAS. Role of fibrin structure in thrombosis and vascular disease. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2011; 83:75-127. [PMID: 21570666 DOI: 10.1016/b978-0-12-381262-9.00003-3] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Fibrin clot formation is a key event in the development of thrombotic disease and is the final step in a multifactor coagulation cascade. Fibrinogen is a large glycoprotein that forms the basis of a fibrin clot. Each fibrinogen molecule is comprised of two sets of Aα, Bβ, and γ polypeptide chains that form a protein containing two distal D regions connected to a central E region by a coiled-coil segment. Fibrin is produced upon cleavage of the fibrinopeptides by thrombin, which can then form double-stranded half staggered oligomers that lengthen into protofibrils. The protofibrils then aggregate and branch, yielding a three-dimensional clot network. Factor XIII, a transglutaminase, cross-links the fibrin stabilizing the clot protecting it from mechanical stress and proteolytic attack. The mechanical properties of the fibrin clot are essential for its function as it must prevent bleeding but still allow the penetration of cells. This viscoelastic property is generated at the level of each individual fiber up to the complete clot. Fibrinolysis is the mechanism of clot removal, and involves a cascade of interacting zymogens and enzymes that act in concert with clot formation to maintain blood flow. Clots vary significantly in structure between individuals due to both genetic and environmental factors and this has an effect on clot stability and susceptibility to lysis. There is increasing evidence that clot structure is a determinant for the development of disease and this review will discuss the determinants for clot structure and the association with thrombosis and vascular disease.
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Affiliation(s)
- Amy L Cilia La Corte
- Division of Cardiovascular and Diabetes Research, Section on Mechanisms of Thrombosis, Leeds Institute for Genetics Health and Therapeutics, Faculty of Medicine and Health, University of Leeds, Leeds, United Kingdom
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Ruggeri ZM, Zarpellon A, Roberts JR, Mc Clintock RA, Jing H, Mendolicchio GL. Unravelling the mechanism and significance of thrombin binding to platelet glycoprotein Ib. Thromb Haemost 2010; 104:894-902. [PMID: 20941453 DOI: 10.1160/th10-09-0578] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Accepted: 09/21/2010] [Indexed: 11/05/2022]
Abstract
The main question concerning the mechanism of a-thrombin binding to platelet membrane glycoprotein (GP)Ib is whether it involves both thrombin exosite I and exosite II. The solution of two independent crystal structures suggests alternative explanations that may actually reflect different modes of binding with distinct pathophysiological significance. With respect to function, it is still unclear whether thrombin binding to GPIb promotes procoagulant and prothrombotic pathways of response to vascular injury or limits such responses by sequestering, at least temporarily, the active enzyme. We review here published information on these topics and touch upon ongoing studies aimed at finding definitive answers to outstanding questions relevant for a better understanding of thrombosis and haemostasis.
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Affiliation(s)
- Zaverio M Ruggeri
- Roon Research Center for Arteriosclerosis and Thrombosis, Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, USA.
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Cui Y, Piao CS, Ha KC, Kim DS, Lee GH, Kim HK, Chae SW, Lee YC, Park SJ, Yoo WH, Kim HR, Chae HJ. Measuring adriamycin-induced cardiac hemodynamic dysfunction with a proteomics approach. Immunopharmacol Immunotoxicol 2010; 32:376-86. [DOI: 10.3109/08923970903440168] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Abstract
Abstract
A fraction of fibrinogen contains a differently spliced γ chain called γ′, which presents itself mainly as heterodimer with the common γA chain as γA/γ′ fibrinogen. The γ′ chain differs from the γA chain in its C-terminus and has important functional implications for fibrinogen. The presence of the γ′ chain modulates thrombin and FXIII activity, influences clot architecture, and eliminates a platelet-binding site. Associations of γA/γ′ fibrinogen levels with arterial and venous thrombosis have been reported, indicating that the functional effects of γA/γ′ fibrinogen may contribute to the pathology of thrombosis. This review summarizes the key biologic aspects of this interesting variant of fibrinogen and discusses inconsistencies in current reports.
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Sabo TM, Maurer MC. Biophysical investigation of GpIbalpha binding to thrombin anion binding exosite II. Biochemistry 2009; 48:7110-22. [PMID: 19591434 DOI: 10.1021/bi900745b] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Substrates and cofactors of the serine protease thrombin (IIa) employ two anion binding exosites (ABE-I and -II) to aid in binding. On the surface of platelets resides the GpIbalpha/beta-GpIX-GpV membrane-bound receptor complex. IIa's ABE-II is proposed to interact with an anionic portion of GpIbalpha which enhances IIa cleavage of PAR-1 and subsequent activation of platelets. In this work, one-dimensional (1D) and two-dimensional (2D) NMR, analytical ultracentrifugation (AUC), and hydrogen-deuterium exchange (HDX) coupled with MALDI-TOF MS were performed to further characterize the features of binding to IIa's ABEs. The described work builds upon investigations performed in a prior study with fibrin(ogen)'s gamma' peptide and IIa [Sabo, T. M., Farrell, D. H., and Maurer, M. C. (2006) Biochemistry 45, 7434-7445]. 1D line broadening NMR (1H and 31P) and 2D trNOESY NMR studies indicate that GpIbalpha residues D274-E285 interact extensively with the IIa surface in an extended conformation. AUC demonstrates that both GpIbalpha (269-286) and gamma' (410-427) peptides interact with IIa with a 1:1 stoichiometry. When the HDX results are compared to those for the ABE-I targeting peptide hirudin (54-65), the data imply that GpIbalpha (269-286), GpIbalpha (1-290), and gamma' (410-427) are indeed directed to ABE-II. The ABE-II binding fragments reduce HDX for sites distant from the interface, suggesting long-range conformational effects. These studies illustrate that GpIbalpha and gamma' target ABE-II with similar consequences on IIa dynamics, albeit with differing structural features.
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Affiliation(s)
- T Michael Sabo
- Department of Chemistry, University of Louisville, 2320 South Brook Street, Louisville, Kentucky 40292, USA
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Petrera NS, Stafford AR, Leslie BA, Kretz CA, Fredenburgh JC, Weitz JI. Long range communication between exosites 1 and 2 modulates thrombin function. J Biol Chem 2009; 284:25620-9. [PMID: 19589779 DOI: 10.1074/jbc.m109.000042] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Although exosites 1 and 2 regulate thrombin activity by binding substrates and cofactors and by allosterically modulating the active site, it is unclear whether there is direct allosteric linkage between the two exosites. To begin to address this, we first titrated a thrombin variant fluorescently labeled at exosite 1 with exosite 2 ligands, HD22 (a DNA aptamer), gamma'-peptide (an analog of the COOH terminus of the gamma'-chain of fibrinogen) or heparin. Concentration-dependent and saturable changes in fluorescence were elicited, supporting inter-exosite linkage. To explore the functional consequences of this phenomenon, we evaluated the capacity of exosite 2 ligands to inhibit thrombin binding to gamma(A)/gamma(A)-fibrin, an interaction mediated solely by exosite 1. When gamma(A)/gamma(A)-fibrinogen was clotted with thrombin in the presence of HD22, gamma'-peptide, or prothrombin fragment 2 there was a dose-dependent and saturable decrease in thrombin binding to the resultant fibrin clots. Furthermore, HD22 reduced the affinity of thrombin for gamma(A)/gamma(A)-fibrin 6-fold and accelerated the dissociation of thrombin from preformed gamma(A)/gamma(A)-fibrin clots. Similar responses were obtained when surface plasmon resonance was used to monitor the interaction of thrombin with gamma(A)/gamma(A)-fibrinogen or fibrin. There is bidirectional communication between the exosites, because exosite 1 ligands, HD1 (a DNA aptamer) or hirudin-(54-65) (an analog of the COOH terminus of hirudin), inhibited the exosite 2-mediated interaction of thrombin with immobilized gamma'-peptide. These findings provide evidence for long range allosteric linkage between exosites 1 and 2 on thrombin, revealing further complexity to the mechanisms of thrombin regulation.
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Affiliation(s)
- Nicolas S Petrera
- Department of Medicine, McMaster University, and Henderson Research Center, Hamilton, Ontario L8V 1C3, Canada
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Totta P, De Cristofaro R, Giampietri C, Aguzzi MS, Faraone D, Capogrossi MC, Facchiano A. Thrombin-mediated impairment of fibroblast growth factor-2 activity. FEBS J 2009; 276:3277-89. [PMID: 19438723 DOI: 10.1111/j.1742-4658.2009.07042.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Thrombin generation increases in several pathological conditions, including cancer, thromboembolism, diabetes and myeloproliferative syndromes. During tumor development, thrombin levels increase along with several other molecules, including cytokines and angiogenic factors. Under such conditions, it is reasonable to predict that thrombin may recognize new low-affinity substrates that usually are not recognized under low-expression levels conditions. In the present study, we hypothesized that fibroblast growth factor (FGF)-2 may be cleaved by thrombin and that such action may lead to an impairment of its biological activity. The evidence collected in the present study indicates that FGF-2-induced proliferation and chemotaxis/invasion of SK-MEL-110 human melanoma cells were significantly reduced when FGF-2 was pre-incubated with active thrombin. The inhibition of proliferation was not influenced by heparin. Phe-Pro-Arg-chloromethyl ketone, a specific inhibitor of the enzymatic activity of thrombin, abolished the thrombin-induced observed effects. Accordingly, both FGF-2-binding to cell membranes as well as FGF-2-induced extracellular signal-regulated kinase phosphorylation were decreased in the presence of thrombin. Finally, HPLC analyses demonstrated that FGF-2 is cleaved by thrombin at the peptide bond between residues Arg42 and Ile43 of the mature human FGF-2 sequence. The apparent k(cat)/K(m) of FGF-2 hydrolysis was 1.1 x 10(4) M(-1) x s(-1), which is comparable to other known low-affinity thrombin substrates. Taken together, these results demonstrate that thrombin digests FGF-2 at the site Arg42-Ile43 and impairs FGF-2 activity in vitro, indicating that FGF-2 is a novel thrombin substrate.
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Affiliation(s)
- Pierangela Totta
- Laboratorio di Patologia Vascolare, IDI-IRCCS, Istituto Dermopatico dell'Immacolata-Istituto di Ricovero e Cura a Carattere Scientifico, Rome, Italy
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The role of procoagulants and anticoagulants in the development of venous thromboembolism. Thromb Res 2009; 123 Suppl 4:S41-5. [DOI: 10.1016/s0049-3848(09)70142-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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