1
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Stark K, Kilani B, Stockhausen S, Busse J, Schubert I, Tran TD, Gaertner F, Leunig A, Pekayvaz K, Nicolai L, Fumagalli V, Stermann J, Stephan F, David C, Müller MB, Heyman B, Lux A, da Palma Guerreiro A, Frenzel LP, Schmidt CQ, Dopler A, Moser M, Chandraratne S, von Brühl ML, Lorenz M, Korff T, Rudelius M, Popp O, Kirchner M, Mertins P, Nimmerjahn F, Iannacone M, Sperandio M, Engelmann B, Verschoor A, Massberg S. Antibodies and complement are key drivers of thrombosis. Immunity 2024; 57:2140-2156.e10. [PMID: 39226900 DOI: 10.1016/j.immuni.2024.08.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Revised: 05/17/2024] [Accepted: 08/07/2024] [Indexed: 09/05/2024]
Abstract
Venous thromboembolism (VTE) is a common, deadly disease with an increasing incidence despite preventive efforts. Clinical observations have associated elevated antibody concentrations or antibody-based therapies with thrombotic events. However, how antibodies contribute to thrombosis is unknown. Here, we show that reduced blood flow enabled immunoglobulin M (IgM) to bind to FcμR and the polymeric immunoglobulin receptor (pIgR), initiating endothelial activation and platelet recruitment. Subsequently, the procoagulant surface of activated platelets accommodated antigen- and FcγR-independent IgG deposition. This leads to classical complement activation, setting in motion a prothrombotic vicious circle. Key elements of this mechanism were present in humans in the setting of venous stasis as well as in the dysregulated immunothrombosis of COVID-19. This antibody-driven thrombosis can be prevented by pharmacologically targeting complement. Hence, our results uncover antibodies as previously unrecognized central regulators of thrombosis. These findings carry relevance for therapeutic application of antibodies and open innovative avenues to target thrombosis without compromising hemostasis.
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Affiliation(s)
- Konstantin Stark
- Medizinische Klinik und Poliklinik I, University Hospital, LMU Munich, Munich, Germany; German Center for Cardiovascular Research (DZHK), partner site Munich Heart Alliance, Munich, Germany; Walter-Brendel Center of Experimental Medicine, Faculty of Medicine, LMU Munich, Munich, Germany.
| | - Badr Kilani
- Medizinische Klinik und Poliklinik I, University Hospital, LMU Munich, Munich, Germany; German Center for Cardiovascular Research (DZHK), partner site Munich Heart Alliance, Munich, Germany; Walter-Brendel Center of Experimental Medicine, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Sven Stockhausen
- Medizinische Klinik und Poliklinik I, University Hospital, LMU Munich, Munich, Germany; German Center for Cardiovascular Research (DZHK), partner site Munich Heart Alliance, Munich, Germany; Walter-Brendel Center of Experimental Medicine, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Johanna Busse
- Medizinische Klinik und Poliklinik I, University Hospital, LMU Munich, Munich, Germany; Walter-Brendel Center of Experimental Medicine, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Irene Schubert
- Medizinische Klinik und Poliklinik I, University Hospital, LMU Munich, Munich, Germany; Walter-Brendel Center of Experimental Medicine, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Thuy-Duong Tran
- Medizinische Klinik und Poliklinik I, University Hospital, LMU Munich, Munich, Germany; Walter-Brendel Center of Experimental Medicine, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Florian Gaertner
- Medizinische Klinik und Poliklinik I, University Hospital, LMU Munich, Munich, Germany; German Center for Cardiovascular Research (DZHK), partner site Munich Heart Alliance, Munich, Germany; Walter-Brendel Center of Experimental Medicine, Faculty of Medicine, LMU Munich, Munich, Germany; Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Alexander Leunig
- Medizinische Klinik und Poliklinik I, University Hospital, LMU Munich, Munich, Germany; German Center for Cardiovascular Research (DZHK), partner site Munich Heart Alliance, Munich, Germany; Walter-Brendel Center of Experimental Medicine, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Kami Pekayvaz
- Medizinische Klinik und Poliklinik I, University Hospital, LMU Munich, Munich, Germany; German Center for Cardiovascular Research (DZHK), partner site Munich Heart Alliance, Munich, Germany; Walter-Brendel Center of Experimental Medicine, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Leo Nicolai
- Medizinische Klinik und Poliklinik I, University Hospital, LMU Munich, Munich, Germany; German Center for Cardiovascular Research (DZHK), partner site Munich Heart Alliance, Munich, Germany; Walter-Brendel Center of Experimental Medicine, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Valeria Fumagalli
- Division of Immunology, Transplantation, and Infectious Diseases, IRCCS San Raffaele Scientific Institute, Milan, Italy; Vita-Salute San Raffaele University, Milan, Italy
| | - Julia Stermann
- Medizinische Klinik und Poliklinik I, University Hospital, LMU Munich, Munich, Germany; German Center for Cardiovascular Research (DZHK), partner site Munich Heart Alliance, Munich, Germany; Walter-Brendel Center of Experimental Medicine, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Felix Stephan
- Medizinische Klinik und Poliklinik I, University Hospital, LMU Munich, Munich, Germany; German Center for Cardiovascular Research (DZHK), partner site Munich Heart Alliance, Munich, Germany; Walter-Brendel Center of Experimental Medicine, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Christian David
- Institute for Cardiovascular Physiology and Pathophysiology, Walter Brendel Center for Experimental Medicine, Biomedical Center (BMC) LMU Munich, Munich, Germany
| | - Martin B Müller
- Walter-Brendel Center of Experimental Medicine, Faculty of Medicine, LMU Munich, Munich, Germany; Department of Anaesthesiology, University Hospital, LMU Munich, Munich, Germany
| | - Birgitta Heyman
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Anja Lux
- Department of Biology, Institute of Genetics, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany; Medical Immunology Campus Erlangen (MICE), Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Alexandra da Palma Guerreiro
- Department I of Internal Medicine, University Hospital Cologne, Cologne 50937, Germany; Center of Integrated Oncology ABCD, University Hospital of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne 50937, Germany
| | - Lukas P Frenzel
- Department I of Internal Medicine, University Hospital Cologne, Cologne 50937, Germany; Center of Integrated Oncology ABCD, University Hospital of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne 50937, Germany
| | - Christoph Q Schmidt
- Institute of Experimental and Clinical Pharmacology, Toxicology and Pharmacology of Natural Products, University of Ulm Medical Center, Ulm, Germany
| | - Arthur Dopler
- Institute of Experimental and Clinical Pharmacology, Toxicology and Pharmacology of Natural Products, University of Ulm Medical Center, Ulm, Germany
| | - Markus Moser
- Department of Molecular Medicine, Max-Planck-Institute of Biochemistry, Martinsried, Germany; Institute of Experimental Hematology, TranslaTUM, Klinikum rechts der Isar der Technischen Universität München, Munich, Germany
| | - Sue Chandraratne
- Medizinische Klinik und Poliklinik I, University Hospital, LMU Munich, Munich, Germany; Walter-Brendel Center of Experimental Medicine, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Marie-Luise von Brühl
- Medizinische Klinik und Poliklinik I, University Hospital, LMU Munich, Munich, Germany; Walter-Brendel Center of Experimental Medicine, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Michael Lorenz
- Medizinische Klinik und Poliklinik I, University Hospital, LMU Munich, Munich, Germany; Walter-Brendel Center of Experimental Medicine, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Thomas Korff
- Division of Cardiovascular Physiology, Institute of Physiology and Pathophysiology, Heidelberg University, Heidelberg, Germany
| | - Martina Rudelius
- Institute of Pathology, Ludwig-Maximilian University, Munich, Germany
| | - Oliver Popp
- Max Delbrück Center for Molecular Medicine (MDC) and Berlin Institute of Health (BIH), Berlin, Germany; German Center for Cardiovascular Research (DZHK), partner site Berlin, Berlin, Germany
| | - Marieluise Kirchner
- Max Delbrück Center for Molecular Medicine (MDC) and Berlin Institute of Health (BIH), Berlin, Germany; German Center for Cardiovascular Research (DZHK), partner site Berlin, Berlin, Germany
| | - Philipp Mertins
- Max Delbrück Center for Molecular Medicine (MDC) and Berlin Institute of Health (BIH), Berlin, Germany; German Center for Cardiovascular Research (DZHK), partner site Berlin, Berlin, Germany
| | - Falk Nimmerjahn
- Department of Biology, Institute of Genetics, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany; Medical Immunology Campus Erlangen (MICE), Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Matteo Iannacone
- Division of Immunology, Transplantation, and Infectious Diseases, IRCCS San Raffaele Scientific Institute, Milan, Italy; Vita-Salute San Raffaele University, Milan, Italy
| | - Markus Sperandio
- Institute for Cardiovascular Physiology and Pathophysiology, Walter Brendel Center for Experimental Medicine, Biomedical Center (BMC) LMU Munich, Munich, Germany
| | - Bernd Engelmann
- Institut für Laboratoriumsmedizin, University Hospital, LMU Munich, Munich, Germany
| | - Admar Verschoor
- Department of Dermatology, Allergy, and Venereology, University of Lübeck, Lübeck, Germany; Department of Otorhinolaryngology, Technische Universität München and Klinikum Rechts der Isar, Munich, Germany.
| | - Steffen Massberg
- Medizinische Klinik und Poliklinik I, University Hospital, LMU Munich, Munich, Germany; German Center for Cardiovascular Research (DZHK), partner site Munich Heart Alliance, Munich, Germany; Walter-Brendel Center of Experimental Medicine, Faculty of Medicine, LMU Munich, Munich, Germany
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2
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Warkentin TE. Autoimmune Heparin-Induced Thrombocytopenia. J Clin Med 2023; 12:6921. [PMID: 37959386 PMCID: PMC10649402 DOI: 10.3390/jcm12216921] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 10/27/2023] [Accepted: 11/01/2023] [Indexed: 11/15/2023] Open
Abstract
Autoimmune thrombocytopenia (aHIT) is a severe subtype of heparin-induced thrombocytopenia (HIT) with atypical clinical features caused by highly pathological IgG antibodies ("aHIT antibodies") that activate platelets even in the absence of heparin. The clinical features of aHIT include: the onset or worsening of thrombocytopenia despite stopping heparin ("delayed-onset HIT"), thrombocytopenia persistence despite stopping heparin ("persisting" or "refractory HIT"), or triggered by small amounts of heparin (heparin "flush" HIT), most cases of fondaparinux-induced HIT, and patients with unusually severe HIT (e.g., multi-site or microvascular thrombosis, overt disseminated intravascular coagulation [DIC]). Special treatment approaches are required. For example, unlike classic HIT, heparin cessation does not result in de-escalation of antibody-induced hemostasis activation, and thus high-dose intravenous immunoglobulin (IVIG) may be indicated to interrupt aHIT-induced platelet activation; therapeutic plasma exchange may be required if high-dose IVIG is ineffective. Also, aHIT patients are at risk for treatment failure with (activated partial thromboplastin time [APTT]-adjusted) direct thrombin inhibitor (DTI) therapy (argatroban, bivalirudin), either because of APTT confounding (where aHIT-associated DIC and resulting APTT prolongation lead to systematic underdosing/interruption of DTI therapy) or because DTI inhibits thrombin-induced protein C activation. Most HIT laboratories do not test for aHIT antibodies, contributing to aHIT under-recognition.
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Affiliation(s)
- Theodore E. Warkentin
- Department of Pathology and Molecular Medicine and Department of Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, ON L8N 3Z5, Canada; ; Tel.: +1-(905)-527-0271 (ext. 46139)
- Service of Benign Hematology, Hamilton Health Sciences (General Site), Hamilton, ON L8L 2X2, Canada
- Transfusion Medicine, Hamilton Regional Laboratory Medicine Program, Hamilton, ON L8L 2X2, Canada
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3
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Schmidt HM, DeVallance ER, Lewis SE, Wood KC, Annarapu GK, Carreño M, Hahn SA, Seman M, Maxwell BA, Hileman EA, Xu JZ, Velayutham M, Geldenhuys WJ, Vitturi DA, Shiva S, Kelley EE, Straub AC. Release of hepatic xanthine oxidase (XO) to the circulation is protective in intravascular hemolytic crisis. Redox Biol 2023; 62:102636. [PMID: 36906950 PMCID: PMC10025133 DOI: 10.1016/j.redox.2023.102636] [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: 01/18/2023] [Revised: 02/09/2023] [Accepted: 02/11/2023] [Indexed: 02/15/2023] Open
Abstract
Xanthine oxidase (XO) catalyzes the catabolism of hypoxanthine to xanthine and xanthine to uric acid, generating oxidants as a byproduct. Importantly, XO activity is elevated in numerous hemolytic conditions including sickle cell disease (SCD); however, the role of XO in this context has not been elucidated. Whereas long-standing dogma suggests elevated levels of XO in the vascular compartment contribute to vascular pathology via increased oxidant production, herein, we demonstrate, for the first time, that XO has an unexpected protective role during hemolysis. Using an established hemolysis model, we found that intravascular hemin challenge (40 μmol/kg) resulted in a significant increase in hemolysis and an immense (20-fold) elevation in plasma XO activity in Townes sickle cell phenotype (SS) sickle mice compared to controls. Repeating the hemin challenge model in hepatocyte-specific XO knockout mice transplanted with SS bone marrow confirmed the liver as the source of enhanced circulating XO as these mice demonstrated 100% lethality compared to 40% survival in controls. In addition, studies in murine hepatocytes (AML12) revealed hemin mediates upregulation and release of XO to the medium in a toll like receptor 4 (TLR4)-dependent manner. Furthermore, we demonstrate that XO degrades oxyhemoglobin and releases free hemin and iron in a hydrogen peroxide-dependent manner. Additional biochemical studies revealed purified XO binds free hemin to diminish the potential for deleterious hemin-related redox reactions as well as prevents platelet aggregation. In the aggregate, data herein reveals that intravascular hemin challenge induces XO release by hepatocytes through hemin-TLR4 signaling, resulting in an immense elevation of circulating XO. This increased XO activity in the vascular compartment mediates protection from intravascular hemin crisis by binding and potentially degrading hemin at the apical surface of the endothelium where XO is known to be bound and sequestered by endothelial glycosaminoglycans (GAGs).
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Affiliation(s)
- Heidi M Schmidt
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Evan R DeVallance
- Center for Inhalation Toxicology, West Virginia University School of Medicine, Morgantown, WV, USA; Department of Physiology and Pharmacology, Health Sciences Center, West Virginia University, Morgantown, WV, USA
| | - Sara E Lewis
- Department of Physiology and Pharmacology, Health Sciences Center, West Virginia University, Morgantown, WV, USA
| | - Katherine C Wood
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Gowtham K Annarapu
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Mara Carreño
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Scott A Hahn
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Madison Seman
- Department of Physiology and Pharmacology, Health Sciences Center, West Virginia University, Morgantown, WV, USA
| | - Brooke A Maxwell
- Department of Physiology and Pharmacology, Health Sciences Center, West Virginia University, Morgantown, WV, USA
| | - Emily A Hileman
- Department of Physiology and Pharmacology, Health Sciences Center, West Virginia University, Morgantown, WV, USA
| | - Julia Z Xu
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA, USA; Division of Hematology /Oncology, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | | | - Werner J Geldenhuys
- Department of Pharmaceutical Sciences, School of Pharmacy, West Virginia University, Morgantown, WV, USA; Department of Neuroscience, School of Medicine, West Virginia University, Morgantown, WV, USA
| | - Dario A Vitturi
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA; Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Sruti Shiva
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA; Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA, USA
| | - Eric E Kelley
- Department of Physiology and Pharmacology, Health Sciences Center, West Virginia University, Morgantown, WV, USA.
| | - Adam C Straub
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA; Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA, USA.
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4
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Meng D, Leng X, Zhang Y, Luo J, Du H, Takagi Y, Dai Z, Wei Q. Comparation of the structural characteristics and biological activities of chondroitin sulfates extracted from notochord and backbone of Chinese sturgeon (Acipenser sinensis). Carbohydr Res 2022; 522:108685. [DOI: 10.1016/j.carres.2022.108685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 09/20/2022] [Accepted: 09/22/2022] [Indexed: 12/01/2022]
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5
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The role of fluid-phase immune complexes in the pathogenesis of heparin-induced thrombocytopenia. Thromb Res 2020; 194:135-141. [PMID: 32788105 DOI: 10.1016/j.thromres.2020.06.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 06/03/2020] [Accepted: 06/05/2020] [Indexed: 11/24/2022]
Abstract
Immune complexes assemble on the platelet surface and cause Fc-mediated platelet activation in heparin-induced thrombocytopenia (HIT); however, it is not known if fluid-phase immune complexes contribute to HIT. The objective of this study was to understand the role of fluid-phase immune complexes in platelet activation and HIT. Binding of wild-type and 15 platelet factor 4 (PF4) mutants to platelets was measured using flow cytometry. Platelet activation was measured using the PF4-dependent 14C-serotonin release assay (PF4-SRA) with KKO and a HIT-patient plasma in the presence of wild-type or PF4 mutants. To activate platelets, we found that a minimal level of wild-type PF4 is required to bind the platelet surface in the presence of KKO (2.67 relative MFI) or HIT-patient plasma (1.71 relative MFI). Only a subset of PF4 mutants was able to support platelet activation, despite having lower surface binding than the minimum binding required of wild-type PF4 (9 mutants with KKO and 2 mutants with HIT-patient plasma). Using individual PF4 mutants, we identified that HIT immune complexes can be formed in fluid-phase and induce platelet activation. Further studies are required to investigate the role of fluid-phase HIT immune complexes in the development of thrombocytopenia and thrombosis associated with clinical HIT.
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6
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Vayne C, Guery EA, Kizlik-Masson C, Rollin J, Bauters A, Gruel Y, Pouplard C. Beneficial effect of exogenous platelet factor 4 for detecting pathogenic heparin-induced thrombocytopenia antibodies. Br J Haematol 2017; 179:811-819. [DOI: 10.1111/bjh.14955] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 08/09/2017] [Indexed: 12/17/2022]
Affiliation(s)
- Caroline Vayne
- Department of Haematology-Haemostasis; University Hospital of Tours; Tours France
- University François Rabelais; UMR CNRS 7292; Tours France
| | - Eve-Anne Guery
- Department of Haematology-Haemostasis; University Hospital of Tours; Tours France
- University François Rabelais; UMR CNRS 7292; Tours France
| | | | - Jérôme Rollin
- Department of Haematology-Haemostasis; University Hospital of Tours; Tours France
- University François Rabelais; UMR CNRS 7292; Tours France
| | - Anne Bauters
- Institute of Haematology-Transfusion; University Hospital of Lille; Lille France
| | - Yves Gruel
- Department of Haematology-Haemostasis; University Hospital of Tours; Tours France
- University François Rabelais; UMR CNRS 7292; Tours France
| | - Claire Pouplard
- Department of Haematology-Haemostasis; University Hospital of Tours; Tours France
- University François Rabelais; UMR CNRS 7292; Tours France
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7
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Hayes V, Johnston I, Arepally GM, McKenzie SE, Cines DB, Rauova L, Poncz M. Endothelial antigen assembly leads to thrombotic complications in heparin-induced thrombocytopenia. J Clin Invest 2017; 127:1090-1098. [PMID: 28218620 DOI: 10.1172/jci90958] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 12/06/2016] [Indexed: 01/27/2023] Open
Abstract
Heparin-induced thrombocytopenia (HIT) is a prothrombotic disorder initiated by antibodies against complexes between human platelet factor 4 (hPF4) and heparin. A better understanding of the events that initiate the prothrombotic state may improve approaches to antithrombotic management. Here, we visualized thrombus formation in an in vivo murine model and an endothelialized microfluidic system that simulate the pathogenesis of HIT. hPF4 released from platelets predominantly bound to peri-injury endothelium and formed HIT antigenic complexes that were dissociated by heparin. In mice expressing both hPF4+ and human platelet IgG Fc receptor IIA (FcγRIIA), infusion of the HIT-like monoclonal antibody KKO increased fibrin and platelet deposition at sites of injury, followed immediately by antigen formation on proximate endothelial cells. After a few minutes, HIT antigen was detected within the thrombus itself at the interface between the platelet core and the surrounding shell. We observed similar results in the humanized, endothelialized microfluidic system. hPF4 and KKO selectively bound to photochemically injured endothelium at sites where surface glycocalyx was reduced. These studies support the concept that the perithrombus endothelium is the predominant site of HIT antigen assembly. This suggests that disrupting antigen formation along the endothelium or protecting the endothelium may provide a therapeutic opportunity to prevent thrombotic complications of HIT, while sparing systemic hemostatic pathways.
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8
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Cai Z, Zhu Z, Greene MI, Cines DB. Atomic features of an autoantigen in heparin-induced thrombocytopenia (HIT). Autoimmun Rev 2016; 15:752-5. [PMID: 26970483 DOI: 10.1016/j.autrev.2016.03.011] [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: 03/01/2016] [Accepted: 03/04/2016] [Indexed: 01/19/2023]
Abstract
Autoantigen development is poorly understood at the atomic level. Heparin-induced thrombocytopenia (HIT) is an autoimmune thrombotic disorder caused by antibodies to an antigen composed of platelet factor 4 (PF4) and heparin or cellular glycosaminoglycans (GAGs). In solution, PF4 exists as an equilibrium among monomers, dimers and tetramers. Structural studies of these interacting components helped delineate a multi-step process involved in the pathogenesis of HIT. First, heparin binds to the 'closed' end of the PF4 tetramer and stabilizes its conformation; exposing the 'open' end. Second, PF4 arrays along heparin/GAG chains, which approximate tetramers, form large antigenic complexes that enhance antibody avidity. Third, pathogenic HIT antibodies bind to the 'open' end of stabilized PF4 tetramers to form an IgG/PF4/heparin ternary immune complex and also to propagate the formation of 'ultralarge immune complexes' (ULCs) that contain multiple IgG antibodies. Fourth, ULCs signal through FcγRIIA receptors, activating platelets and monocytes directly and generating thrombin, which transactivates hematopoietic and endothelial cells. A non-pathogenic anti-PF4 antibody prevents tetramer formation, binding of pathogenic antibody, platelet activation and thrombosis, providing a new approach to manage HIT. An improved understanding of the pathogenesis of HIT may lead to novel diagnostics and therapeutics for this autoimmune disease.
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Affiliation(s)
- Zheng Cai
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Zhiqiang Zhu
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Mark I Greene
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Douglas B Cines
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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9
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Platelet transactivation by monocytes promotes thrombosis in heparin-induced thrombocytopenia. Blood 2015; 127:464-72. [PMID: 26518435 DOI: 10.1182/blood-2013-11-539262] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 10/21/2015] [Indexed: 12/13/2022] Open
Abstract
Heparin-induced thrombocytopenia (HIT) is characterized by a high incidence of thrombosis, unlike other antibody-mediated causes of thrombocytopenia. We have shown that monocytes complexed with surface-bound platelet factor 4 (PF4) activated by HIT antibodies contribute to the prothrombotic state in vivo, but the mechanism by which this occurs and the relationship to the requirement for platelet activation via fragment crystallizable (Fc)γRIIA is uncertain. Using a microfluidic model and human or murine blood, we confirmed that activation of monocytes contributes to the prothrombotic state in HIT and showed that HIT antibodies bind to monocyte FcγRIIA, which activates spleen tyrosine kinase and leads to the generation of tissue factor (TF) and thrombin. The combination of direct platelet activation by HIT immune complexes through FcγRIIA and transactivation by monocyte-derived thrombin markedly increases Annexin V and factor Xa binding to platelets, consistent with the formation of procoagulant coated platelets. These data provide a model of HIT wherein a combination of direct FcγRIIA-mediated platelet activation and monocyte-derived thrombin contributes to thrombosis in HIT and identifies potential new targets for lessening this risk.
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10
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Flebus L, Lombart F, Martinez-Jothar L, Sevrin C, Delierneux C, Oury C, Grandfils C. In vitro study of the specific interaction between poly(2-dimethylamino ethylmethacrylate) based polymers with platelets and red blood cells. Int J Pharm 2015; 492:55-64. [PMID: 26136199 DOI: 10.1016/j.ijpharm.2015.06.036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Revised: 06/19/2015] [Accepted: 06/20/2015] [Indexed: 01/24/2023]
Abstract
Poly(2-dimethylamino)ethyl methacrylate (PDMAEMA) is an attractive polycation frequently proposed as a non-viral vector for gene therapy. As expected for other cationic carriers, intravenous administration of PDMAEMA can result in its ionic complexation with various negatively charged domains found within the blood. To gain more insight into this polycation hemoreactivity, we followed the binding kinetics of a free form (FF) of fluorescein labelled PDMAEMA (Mn below 15 kDa) in normal human blood using flow cytometry. This in vitro study highlighted that platelets display higher affinity for this polycation compared to red blood cells (RBCs), with an adsorption isotherm characteristics of a specific saturable binding site. PDMAEMA (1-20 μg/mL) exerted a concentration dependent proaggregant effect with a biphasic aggregation of washed platelets. Activation of platelets was also noticed in whole blood with the expression of P-selectin and fibrinogen on platelet surface. Although additional studies would be needed in order to elucidate the mechanism of PDMAEMA mediated activation of platelets, our manuscript provides important information on the hemoreactivity of FF PDMAEMA.
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Affiliation(s)
- Luca Flebus
- Interfacultary Research Center of Biomaterials, University of Liège, Institute of Chemistry, Building B6C, Sart-Tilman, Liège 4000, Belgium.
| | - François Lombart
- Interfacultary Research Center of Biomaterials, University of Liège, Institute of Chemistry, Building B6C, Sart-Tilman, Liège 4000, Belgium.
| | - Lucía Martinez-Jothar
- Interfacultary Research Center of Biomaterials, University of Liège, Institute of Chemistry, Building B6C, Sart-Tilman, Liège 4000, Belgium.
| | - Chantal Sevrin
- Interfacultary Research Center of Biomaterials, University of Liège, Institute of Chemistry, Building B6C, Sart-Tilman, Liège 4000, Belgium.
| | - Céline Delierneux
- Laboratory of Thrombosis and Haemostasis, GIGA-Cardiovascular Sciences, University of Liège, Belgium.
| | - Cécile Oury
- Laboratory of Thrombosis and Haemostasis, GIGA-Cardiovascular Sciences, University of Liège, Belgium.
| | - Christian Grandfils
- Interfacultary Research Center of Biomaterials, University of Liège, Institute of Chemistry, Building B6C, Sart-Tilman, Liège 4000, Belgium.
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11
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Dengue virus binding and replication by platelets. Blood 2015; 126:378-85. [PMID: 25943787 DOI: 10.1182/blood-2014-09-598029] [Citation(s) in RCA: 118] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 04/28/2015] [Indexed: 02/07/2023] Open
Abstract
Dengue virus (DENV) infection causes ∼200 million cases of severe flulike illness annually, escalating to life-threatening hemorrhagic fever or shock syndrome in ∼500,000. Although thrombocytopenia is typical of both mild and severe diseases, the mechanism triggering platelet reduction is incompletely understood. As a probable initiating event, direct purified DENV-platelet binding was followed in the current study by quantitative reverse transcription-polymerase chain reaction and confirmed antigenically. Approximately 800 viruses specifically bound per platelet at 37°C. Fewer sites were observed at 25°C, the blood bank storage temperature (∼350 sites), or 4°C, known to attenuate virus cell entry (∼200 sites). Dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN) and heparan sulfate proteoglycan were implicated as coreceptors because only the combination of anti-DC-SIGN and low-molecular-weight heparin prevented binding. Interestingly, at 37°C and 25°C, platelets replicated the positive sense single-stranded RNA genome of DENV by up to ∼4-fold over 7 days. Further time course experiments demonstrated production of viral NS1 protein, which is known to be highly antigenic in patient serum. The infectivity of DENV intrinsically decayed in vitro, which was moderated by platelet-mediated generation of viable progeny. This was shown using a transcription inhibitor and confirmed by freeze-denatured platelets being incapable of replicating the DENV genome. For the first time, these data demonstrate that platelets directly bind DENV saturably and produce infectious virus. Thus, expression of antigen encoded by DENV is a novel consideration in the pathogen-induced thrombocytopenia mechanism. These results furthermore draw attention to the possibility that platelets may produce permissive RNA viruses in addition to DENV.
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12
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Heparin-independent, PF4-dependent binding of HIT antibodies to platelets: implications for HIT pathogenesis. Blood 2014; 125:155-61. [PMID: 25342714 DOI: 10.1182/blood-2014-06-580894] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Antibodies specific for platelet factor 4 (PF4)/heparin complexes are the hallmark of heparin-induced thrombocytopenia and thrombosis (HIT), but many antibody-positive patients have normal platelet counts. The basis for this is not fully understood, but it is believed that antibodies testing positive in the serotonin release assay (SRA) are the most likely to cause disease. We addressed this issue by characterizing PF4-dependent binding of HIT antibodies to intact platelets and found that most antibodies testing positive in the SRA, but none of those testing negative, bind to and activate platelets when PF4 is present without any requirement for heparin (P < .0001). Binding of SRA-positive antibodies to platelets was inhibited by chondroitinase ABC digestion (P < .05) and by the addition of chondroitin-4-sulfate (CS) or heparin in excess quantities. The findings suggest that although all HIT antibodies recognize PF4 in a complex with heparin, only a subset of these antibodies recognize more subtle epitopes induced in PF4 when it binds to CS, the major platelet glycosaminoglycan. Antibodies having this property could explain "delayed HIT" seen in some individuals after discontinuation of heparin and the high risk for thrombosis that persists for weeks in patients recovered from HIT.
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13
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Heparin affects the interaction of kininogen on endothelial cells. Biochimie 2011; 93:1839-45. [DOI: 10.1016/j.biochi.2011.07.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 07/04/2011] [Indexed: 11/21/2022]
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14
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Abstract
Heparin-induced thrombocytopenia (HIT) is a life- and limb-threatening thrombotic disorder that develops after exposure to heparin, often in the setting of inflammation. We have shown previously that HIT is associated with antibodies to complexes that form between platelet factor 4 and glycosaminoglycan (GAG) side chains on the surface of platelets. However, thrombosis can occur in the absence of thrombocytopenia. We now show that platelet factor 4 binds to monocytes and forms antigenic complexes with their surface GAG side chains more efficiently than on platelets likely due to differences in GAG composition. Binding to monocytes is enhanced when the cells are activated by endotoxin. Monocyte accumulation within developing arteriolar thrombi was visualized by situ microscopy. Monocyte depletion or inactivation in vivo attenuates thrombus formation induced by photochemical injury of the carotid artery in a modified murine model of HIT while paradoxically exacerbating thrombocytopenia. These studies demonstrate a previously unappreciated role for monocytes in the pathogenesis of arterial thrombosis in HIT and suggest that therapies targeting these cells might provide an alternative approach to help limit thrombosis in this and possibly other thrombotic disorders that occur in the setting of inflammation.
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15
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Role of the platelet chemokine platelet factor 4 (PF4) in hemostasis and thrombosis. Thromb Res 2009; 125:292-6. [PMID: 20004006 DOI: 10.1016/j.thromres.2009.11.023] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2009] [Revised: 11/19/2009] [Accepted: 11/22/2009] [Indexed: 11/24/2022]
Abstract
Chemokines are a family of small proteins that have significant roles in inflammation, angiogenesis and cellular homing. Since inflammation and hemostasis/thrombosis have multiple overlapping roles and pathways, one could expect that some chemokines would also have biologically significant roles in hemostasis/thrombosis as well. This would especially be true for chemokines that are localized solely or predominantly within platelets and released in large amounts at sites of platelet activation such as platelet factor 4 (PF4, CXCL4) and its closely related chemokine, platelet basic protein (PBP, CXCL7). Our group and others have clearly demonstrated an in vivo role for PF4 in hemostasis/thrombosis, but not for PBP, which in contrast has clear proinflammatory properties. This review will focus on PF4 and its potential roles in hemostasis/thrombosis and the underlying pathways by which PF4 may be especially important in such pathologic thrombotic states as heparin-induced thrombocytopenia (HIT) and septic shock.
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16
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Paredes-Gamero EJ, Craveiro RB, Pesquero JB, França JP, Oshiro MEM, Ferreira AT. Activation of P2Y1 receptor triggers two calcium signaling pathways in bone marrow erythroblasts. Eur J Pharmacol 2006; 534:30-8. [PMID: 16487961 DOI: 10.1016/j.ejphar.2006.01.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2006] [Accepted: 01/10/2006] [Indexed: 11/30/2022]
Abstract
In this study, we describe the presence of P2 receptor subtypes and Ca2+ signaling in erythroblasts. ATP and ADP produced a biphasic increase of intracellular Ca2+ concentration ([Ca2+]i), with an initial transient phase followed by a sustained phase. Reverse transcription polymerase chain reaction (RT-PCR) showed the expression of P2Y1, P2Y2 and P2Y12. The selective P2Y1 receptor antagonist 2'-deoxy-N6-methyl-adenosine-3',5'-diphosphate (MRS2179) and the G(i) protein inhibitor pertussis toxin blocked Ca2+ increase. The initial transient [Ca2+]i increase phase was sensitive to the 1,4,5-inositol trisphosphate (IP3) receptor blocker 2-aminoethoxy-diphenylborate (2-APB), while the sustained phase was sensitive to the protein kinase C (PKC) inhibitor 2-[1-(3-dimethylaminopropyl)-1H-indol-3-yl]-3-(1H-indol-3-yl)-maleimide (GF109203X) and calcium calmodulin kinase II (CaMKII) inhibitor 1-[N,O-bis(5-isoquinolinesulfonyl)-N-methyl-L-tyrosyl]-4-phenylpiperazine (KN-62). In addition, the PKC activator phorbol-12,13-dibutyrate (PDBu) produced increase of [Ca2+]i. Flow cytometry analysis showed the expression of Ca2+-dependent PKC alpha, betaI, gamma and phospho-CaMKII. These results suggest that the activation of the P2Y1 receptor triggers two different [Ca2+]i increase pathways, one IP3-dependent and the other kinase-dependent.
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MESH Headings
- 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine/analogs & derivatives
- 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine/pharmacology
- Adenosine Diphosphate/analogs & derivatives
- Adenosine Diphosphate/pharmacology
- Adenosine Triphosphate/pharmacology
- Animals
- Bone Marrow Cells/drug effects
- Bone Marrow Cells/metabolism
- Boron Compounds/pharmacology
- Calcium Channels/drug effects
- Calcium Channels/metabolism
- Calcium Signaling
- Calcium-Calmodulin-Dependent Protein Kinase Type 2
- Calcium-Calmodulin-Dependent Protein Kinases/antagonists & inhibitors
- Calcium-Calmodulin-Dependent Protein Kinases/metabolism
- Dose-Response Relationship, Drug
- Erythroblasts/drug effects
- Erythroblasts/metabolism
- Female
- Indoles/pharmacology
- Inositol 1,4,5-Trisphosphate Receptors
- Maleimides/pharmacology
- Mice
- Mice, Inbred C57BL
- Protein Kinase C/antagonists & inhibitors
- Protein Kinase C/metabolism
- Protein Kinase Inhibitors/pharmacology
- RNA, Messenger/metabolism
- Receptors, Cytoplasmic and Nuclear/drug effects
- Receptors, Cytoplasmic and Nuclear/metabolism
- Receptors, Purinergic P2/drug effects
- Receptors, Purinergic P2/genetics
- Receptors, Purinergic P2/metabolism
- Receptors, Purinergic P2Y1
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Affiliation(s)
- Edgar Julian Paredes-Gamero
- Department of Biophysics, Universidade Federal de São Paulo, Escola Paulista de Medicina, Rua Botucatu 862, 04023-062, São Paulo, SP, Brazil.
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17
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Sampaio LO, Nader HB. Emergence and structural characteristics of chondroitin sulfates in the animal kingdom. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2006; 53:233-51. [PMID: 17239769 DOI: 10.1016/s1054-3589(05)53011-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Affiliation(s)
- Lucia O Sampaio
- Disciplina de Biologia Molecular, Departamento de Bioquímica, Universidade Federal de São Paulo, Brazil
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18
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Rauova L, Zhai L, Kowalska MA, Arepally GM, Cines DB, Poncz M. Role of platelet surface PF4 antigenic complexes in heparin-induced thrombocytopenia pathogenesis: diagnostic and therapeutic implications. Blood 2005; 107:2346-53. [PMID: 16304054 PMCID: PMC1895727 DOI: 10.1182/blood-2005-08-3122] [Citation(s) in RCA: 183] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Heparin-induced thrombocytopenia (HIT) antibodies recognize complexes between heparin and platelet factor 4 (PF4). Heparin and PF4 bind HIT antibodies only over a narrow molar ratio. We explored the involvement of platelet surface-bound PF4 as an antigen in the pathogenesis of experimental HIT. We show that cell-surface PF4 complexes are also antigenic only over a restricted concentration range of PF4. Heparin is not required for HIT antibody binding but shifts the concentration of PF4 needed for optimal surface antigenicity to higher levels. These data are supported by in vitro studies involving both human and murine platelets with exogenous recombinant human (h) PF4 and either an anti-PF4-heparin monoclonal antibody (KKO) or HIT immunoglobulin. Injection of KKO into transgenic mice expressing different levels of hPF4 demonstrates a correlation between the severity of the thrombocytopenia and platelet hPF4 expression. Therapeutic interventions in this model using high-dose heparin or protamine sulfate support the pathogenic role of surface PF4 antigenic complexes in the etiology of HIT. We believe that this focus on surface PF4 advances our understanding of the pathogenesis of HIT, suggests ways to identify patients at high risk to develop HIT upon heparin exposure, and offers new therapeutic strategies.
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Affiliation(s)
- Lubica Rauova
- Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
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19
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Calabrò L, Musolino C, Spatari G, Vinci R, Calatroni A. Increased concentration of circulating acid glycosaminoglycans in chronic lymphocytic leukaemia and essential thrombocythaemia. Clin Chim Acta 1998; 269:185-99. [PMID: 9526677 DOI: 10.1016/s0009-8981(97)00200-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
To verify whether the increase in the number of circulating blood cells that synthesize glycosaminoglycans, B-lymphocytes or platelets, in proliferative disorders, may be associated with changes in the circulation of acid glycosaminoglycans, the serum and plasma concentrations of these polysaccharides have been measured in terms of their sugar components, following isolation and purification by chromatographic methods, in patients with chronic lymphocytic leukaemia or with essential thrombocythaemia and in healthy controls. In the patients, the concentrations of total circulating glycosaminoglycans and of both glucosamine-containing and galactosamine-containing serum glycosaminoglycans were significantly higher than in controls. These concentrations did not significantly correlate with the number of lymphocytes in patients with chronic lymphocytic leukaemia and of platelets in patients with essential thrombocythaemia. Analytical data suggest that excess glycosaminoglycans are mainly composed of chondroitin sulphate molecules and contain heparan sulphate structures.
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Affiliation(s)
- L Calabrò
- Istituto Pluridisciplinare di Fisiologia Umana, University of Messina, Italy
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20
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Schick BP, Pestina TI, San Antonio JD, Stenberg PE, Jackson CW. Decreased serglycin proteoglycan size is associated with the platelet alpha granule storage defect in Wistar Furth hereditary macrothrombocytopenic rats. Serglycin binding affinity to type I collagen is unaltered. J Cell Physiol 1997; 172:87-93. [PMID: 9207929 DOI: 10.1002/(sici)1097-4652(199707)172:1<87::aid-jcp10>3.0.co;2-l] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The Wistar Furth (WF) rat has a hereditary defect in platelet formation that resembles gray platelet syndrome of man with a large mean platelet volume and platelet alpha granule deficiency. The alpha granule abnormality is suggestive of a defect in granule packaging and/or stability. Proteoglycans are hypothesized to play a role in granule packaging. Therefore, we have analyzed the structure of the platelet proteoglycan, serglycin, in platelets of WF and normal Wistar rats. Normal and Wistar Furth rats were injected with 35S-sulfate to label platelet proteoglycans via synthesis by the megakaryocytes, and platelets were isolated 3 days later. We found that WF rat platelets have only one-third of the normal proteoglycan mass per unit platelet volume, and the proteoglycans are smaller in hydrodynamic size with shorter glycosaminoglycan chains than those of Wistar rats. However, WF rat platelet proteoglycans showed no defect in binding to collagen on affinity coelectrophoresis gels. We conclude that the structure of WF rat platelet proteoglycans is abnormal, and speculate that this abnormality may contribute to abnormal packaging of the alpha granule contents. Leakage of alpha granule contents into the marrow by platelets and megakaryocytes could perturb the marrow matrix, and promote the development of myelofibrosis noted in gray platelet syndrome.
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Affiliation(s)
- B P Schick
- Cardeza Foundation for Hematologic Research, Jefferson Medical College of Thomas Jefferson University, Philadelphia, PA 19107, USA
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21
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Donato JL, Marcondes S, Antunes E, Nogueira MD, Nader HB, Dietrich CP, Rendu F, de Nucci G. Role of chondroitin 4-sulphate as a receptor for polycation induced human platelet aggregation. Br J Pharmacol 1996; 119:1447-53. [PMID: 8968554 PMCID: PMC1915828 DOI: 10.1111/j.1476-5381.1996.tb16057.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
1. Proteoglycans provide negatively charged sites on the surface of platelets, leukocytes and endothelial cells. Since chondroitin 4-sulphate is the main proteoglycan present on the platelet surface, the role of this molecule in mediating the activation of human platelets by polylysine was studied. 2. Platelets were desensitized with phorbol 12-myristate 13-acetate (PMA, 10 nM) 5 min before the addition of polylysine to platelet-rich plasma (PRP). Changes in the intracellular Ca2+ concentration were measured in fura2-am (2 microM) loaded platelets and protein phosphorylation was assessed by autoradiography of the electrophoretic profile obtained from [32P]-phosphate labelled platelets. The release of dense granule contents was measured in [14C]-5-hydroxytryptamine loaded platelets and the synthesis of thromboxane (TXA2) was assessed by radioimmunoassay. Surface chondroitin 4-sulphate proteoglycan was degraded by incubating platelets with different concentrations of chondroitinase AC (3 min, 37 degrees C). The amount of chondroitin 4-sulphate remaining in the platelets was then quantified after proteolysis and agarose gel electrophoresis. 3. The addition of PMA to PRP before polylysine inhibited the aggregation by 88 +/- 18% (n = 3). Staurosporine (1 microM, 5 min) prevented the PMA-induced inhibition. Chondroitinase AC (4 pu ml-1 to 400 muu ml-1, 3 min) abolished the polylysine-induced aggregation in PRP but caused only a discrete inhibition of ADP-induced aggregation. The concentration of chrondroitin 4-sulphate in PRP (0.96 +/- 0.2 microgram/10(8) platelets, n = 3) and in washed platelets (WP; 0.35 +/- 0.1 microgram/10(8) platelets, n = 3) was significantly reduced following incubation with chondroitinase AC (PRP = 0.63 +/- 0.1 microgram/10(8) platelets and WP = 0.08 +/- 0.06 microgram/10(8) platelets). 4. Washed platelets had a significantly lower concentration of chondroitin 4-sulphate than platelets in PRP. The addition of polylysine to WP induced a rapid increase in light transmission which was not accompanied by TXA2 synthesis or the release of dense granule contents. This effect was not inhibited by sodium nitroprusside (SNP), iloprost, EDTA or the peptide RGDS. This event was accompanied by the discrete phosphorylation of plekstrin and myosin light chain, which were inhibited by staurosporine (10 microM, 10 min). The hydrolysis of platelet surface chondroitin 4-sulphate strongly reduced the polylysine-induced phosphorylation. 5. Our results indicate that polylysine activates platelets through a specific receptor which could be the proteoglycan chondroitin 4-sulphate present on the platelet membrane.
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Affiliation(s)
- J L Donato
- Department of Pharmacology, Faculty of Medical Sciences, UNICAMP, São Paulo, Brazil
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22
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Oliveira FW, Chavante SF, Santos EA, Dietrich CP, Nader HB. Appearance and fate of a beta-galactanase, alpha, beta-galactosidases, heparan sulfate and chondroitin sulfate degrading enzymes during embryonic development of the mollusc Pomacea sp. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1200:241-6. [PMID: 8068709 DOI: 10.1016/0304-4165(94)90163-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The characterization and properties of a beta-galactanase and alpha- and beta-galactosidases as well as heparan sulfate and chondroitin sulfate degrading enzymes which appear during the 15 days of the embryonic development of the mollusc Pomacea sp. is reported. The beta-galactanase, which appears around day 7 of development, was separated from alpha- and beta-galactosidase which emerge at day 1 and 4 after oviposition, respectively. The galactanase seems to be responsible for the degradation of an acidic beta-galactan (which is also synthesized by the eggs around day 5) to galactose and di- and tri-galactosides. Heparan sulfate appears around day 10 of development together with a heparan sulfate endoglucuronidase responsible for the degradation of its N-acetylated region. An alpha-N-acetylglucosaminidase and a beta-glucuronidase which act upon the N-acetylated fragments formed from heparan sulfate emerge around day 4 of development. Chondroitin sulfate and a chondroitin sulfate sulfatase emerge around day 9 of development whereas a beta-N-acetylgalactosaminidase and the beta beta-galactan, heparan and chondroitin sulfate, respectively. The possible role of these elements in the migration of mesenchymal cells, in the processes of cell-cell recognition and control of cell growth is discussed.
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Affiliation(s)
- F W Oliveira
- Department of Biochemistry, Universidade Federal do Rio Grande do Norte, Natal, Brazil
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24
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Mas-Oliva J, Arnold K, Wagner W, Phillips D, Pitas R, Innerarity T. Isolation and characterization of a platelet-derived macrophage-binding proteoglycan. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)37006-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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25
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Platelet/endothelial cell adhesion molecule-1 (CD31)-mediated cellular aggregation involves cell surface glycosaminoglycans. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)82354-7] [Citation(s) in RCA: 129] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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