1
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The marriage of chemokines and galectins as functional heterodimers. Cell Mol Life Sci 2021; 78:8073-8095. [PMID: 34767039 PMCID: PMC8629806 DOI: 10.1007/s00018-021-04010-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 10/05/2021] [Accepted: 10/22/2021] [Indexed: 12/11/2022]
Abstract
Trafficking of leukocytes and their local activity profile are of pivotal importance for many (patho)physiological processes. Fittingly, microenvironments are complex by nature, with multiple mediators originating from diverse cell types and playing roles in an intimately regulated manner. To dissect aspects of this complexity, effectors are initially identified and structurally characterized, thus prompting familial classification and establishing foci of research activity. In this regard, chemokines present themselves as role models to illustrate the diversification and fine-tuning of inflammatory processes. This in turn discloses the interplay among chemokines, their cell receptors and cognate glycosaminoglycans, as well as their capacity to engage in new molecular interactions that form hetero-oligomers between themselves and other classes of effector molecules. The growing realization of versatility of adhesion/growth-regulatory galectins that bind to glycans and proteins and their presence at sites of inflammation led to testing the hypothesis that chemokines and galectins can interact with each other by protein-protein interactions. In this review, we present some background on chemokines and galectins, as well as experimental validation of this chemokine-galectin heterodimer concept exemplified with CXCL12 and galectin-3 as proof-of-principle, as well as sketch out some emerging perspectives in this arena.
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2
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Nording H, Baron L, Haberthür D, Emschermann F, Mezger M, Sauter M, Sauter R, Patzelt J, Knoepp K, Nording A, Meusel M, Meyer-Saraei R, Hlushchuk R, Sedding D, Borst O, Eitel I, Karsten CM, Feil R, Pichler B, Erdmann J, Verschoor A, Chavakis E, Chavakis T, von Hundelshausen P, Köhl J, Gawaz M, Langer HF. The C5a/C5a receptor 1 axis controls tissue neovascularization through CXCL4 release from platelets. Nat Commun 2021; 12:3352. [PMID: 34099640 PMCID: PMC8185003 DOI: 10.1038/s41467-021-23499-w] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Accepted: 03/28/2021] [Indexed: 02/05/2023] Open
Abstract
Platelets contribute to the regulation of tissue neovascularization, although the specific factors underlying this function are unknown. Here, we identified the complement anaphylatoxin C5a-mediated activation of C5a receptor 1 (C5aR1) on platelets as a negative regulatory mechanism of vessel formation. We showed that platelets expressing C5aR1 exert an inhibitory effect on endothelial cell functions such as migration and 2D and 3D tube formation. Growth factor- and hypoxia-driven vascularization was markedly increased in C5ar1-/- mice. Platelet-specific deletion of C5aR1 resulted in a proangiogenic phenotype with increased collateralization, capillarization and improved pericyte coverage. Mechanistically, we found that C5a induced preferential release of CXC chemokine ligand 4 (CXCL4, PF4) from platelets as an important antiangiogenic paracrine effector molecule. Interfering with the C5aR1-CXCL4 axis reversed the antiangiogenic effect of platelets both in vitro and in vivo.In conclusion, we identified a mechanism for the control of tissue neovascularization through C5a/C5aR1 axis activation in platelets and subsequent induction of the antiangiogenic factor CXCL4.
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Affiliation(s)
- Henry Nording
- Cardioimmunology Group, Medical Clinic II, University Heart Center Lübeck, Lübeck, Germany ,grid.452396.f0000 0004 5937 5237DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Lübeck/Kiel, Lübeck, Germany
| | - Lasse Baron
- Cardioimmunology Group, Medical Clinic II, University Heart Center Lübeck, Lübeck, Germany
| | - David Haberthür
- grid.5734.50000 0001 0726 5157Institute of Anatomy, University of Bern, Bern, Switzerland
| | - Frederic Emschermann
- grid.10392.390000 0001 2190 1447University Hospital, Department of Cardiovascular Medicine, Eberhard Karls University, Tübingen, Germany
| | - Matthias Mezger
- Cardioimmunology Group, Medical Clinic II, University Heart Center Lübeck, Lübeck, Germany
| | - Manuela Sauter
- Cardioimmunology Group, Medical Clinic II, University Heart Center Lübeck, Lübeck, Germany
| | - Reinhard Sauter
- Cardioimmunology Group, Medical Clinic II, University Heart Center Lübeck, Lübeck, Germany
| | - Johannes Patzelt
- grid.412468.d0000 0004 0646 2097University Hospital, Medical Clinic II, University Heart Center Lübeck, Lübeck, Germany
| | - Kai Knoepp
- grid.9018.00000 0001 0679 2801Department of Internal Medicine III, Cardiology, Angiology and Intensive Care Medicine, Martin-Luther-University Halle (Saale), Halle (Saale), Germany
| | - Anne Nording
- grid.10392.390000 0001 2190 1447Institute of Medical Genetics and Applied Genomics, Eberhard Karls University, Tübingen, Germany
| | - Moritz Meusel
- grid.412468.d0000 0004 0646 2097University Hospital, Medical Clinic II, University Heart Center Lübeck, Lübeck, Germany
| | - Roza Meyer-Saraei
- grid.452396.f0000 0004 5937 5237DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Lübeck/Kiel, Lübeck, Germany ,grid.412468.d0000 0004 0646 2097University Hospital, Medical Clinic II, University Heart Center Lübeck, Lübeck, Germany
| | - Ruslan Hlushchuk
- grid.5734.50000 0001 0726 5157Institute of Anatomy, University of Bern, Bern, Switzerland
| | - Daniel Sedding
- grid.9018.00000 0001 0679 2801Department of Internal Medicine III, Cardiology, Angiology and Intensive Care Medicine, Martin-Luther-University Halle (Saale), Halle (Saale), Germany
| | - Oliver Borst
- grid.10392.390000 0001 2190 1447University Hospital, Department of Cardiovascular Medicine, Eberhard Karls University, Tübingen, Germany
| | - Ingo Eitel
- grid.452396.f0000 0004 5937 5237DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Lübeck/Kiel, Lübeck, Germany ,grid.412468.d0000 0004 0646 2097University Hospital, Medical Clinic II, University Heart Center Lübeck, Lübeck, Germany
| | - Christian M. Karsten
- grid.4562.50000 0001 0057 2672Institute for Systemic Inflammation Research, University of Lübeck, Lübeck, Germany
| | - Robert Feil
- grid.10392.390000 0001 2190 1447Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Bernd Pichler
- grid.10392.390000 0001 2190 1447Institute for Preclinical Imaging, Eberhard Karls University, Tübingen, Germany
| | - Jeanette Erdmann
- grid.452396.f0000 0004 5937 5237DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Lübeck/Kiel, Lübeck, Germany ,grid.4562.50000 0001 0057 2672Institute for Cardiogenetics, University of Lübeck, Lübeck, Germany
| | - Admar Verschoor
- grid.4562.50000 0001 0057 2672Institute for Systemic Inflammation Research, University of Lübeck, Lübeck, Germany
| | - Emmanouil Chavakis
- grid.411088.40000 0004 0578 8220Department for Internal Medicine III/Cardiology, University Hospital of the Johann-Wolfgang Goethe University, Frankfurt am Main, Germany
| | - Triantafyllos Chavakis
- grid.4488.00000 0001 2111 7257Department of Clinical Pathobiochemistry, Institute of Clinical Chemistry and Laboratory Medicine, Medical Faculty, Technische Universität Dresden, Dresden, Germany
| | - Philipp von Hundelshausen
- grid.5252.00000 0004 1936 973XInstitute for Cardiovascular Prevention, Ludwig Maximilians University Munich, Munich, Germany
| | - Jörg Köhl
- grid.4562.50000 0001 0057 2672Institute for Systemic Inflammation Research, University of Lübeck, Lübeck, Germany ,grid.239573.90000 0000 9025 8099Division of Immunobiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH USA
| | - Meinrad Gawaz
- grid.10392.390000 0001 2190 1447University Hospital, Department of Cardiovascular Medicine, Eberhard Karls University, Tübingen, Germany
| | - Harald F. Langer
- Cardioimmunology Group, Medical Clinic II, University Heart Center Lübeck, Lübeck, Germany ,grid.452396.f0000 0004 5937 5237DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Lübeck/Kiel, Lübeck, Germany ,grid.412468.d0000 0004 0646 2097University Hospital, Medical Clinic II, University Heart Center Lübeck, Lübeck, Germany
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3
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Crijns H, Vanheule V, Proost P. Targeting Chemokine-Glycosaminoglycan Interactions to Inhibit Inflammation. Front Immunol 2020; 11:483. [PMID: 32296423 PMCID: PMC7138053 DOI: 10.3389/fimmu.2020.00483] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Accepted: 03/02/2020] [Indexed: 12/12/2022] Open
Abstract
Leukocyte migration into tissues depends on the activity of chemokines that form concentration gradients to guide leukocytes to a specific site. Interaction of chemokines with their specific G protein-coupled receptors (GPCRs) on leukocytes induces leukocyte adhesion to the endothelial cells, followed by extravasation of the leukocytes and subsequent directed migration along the chemotactic gradient. Interaction of chemokines with glycosaminoglycans (GAGs) is crucial for extravasation in vivo. Chemokines need to interact with GAGs on endothelial cells and in the extracellular matrix in tissues in order to be presented on the endothelium of blood vessels and to create a concentration gradient. Local chemokine retention establishes a chemokine gradient and prevents diffusion and degradation. During the last two decades, research aiming at reducing chemokine activity mainly focused on the identification of inhibitors of the interaction between chemokines and their cognate GPCRs. This approach only resulted in limited success. However, an alternative strategy, targeting chemokine-GAG interactions, may be a promising approach to inhibit chemokine activity and inflammation. On this line, proteins derived from viruses and parasites that bind chemokines or GAGs may have the potential to interfere with chemokine-GAG interactions. Alternatively, chemokine mimetics, including truncated chemokines and mutant chemokines, can compete with chemokines for binding to GAGs. Such truncated or mutated chemokines are characterized by a strong binding affinity for GAGs and abrogated binding to their chemokine receptors. Finally, Spiegelmers that mask the GAG-binding site on chemokines, thereby preventing chemokine-GAG interactions, were developed. In this review, the importance of GAGs for chemokine activity in vivo and strategies that could be employed to target chemokine-GAG interactions will be discussed in the context of inflammation.
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Affiliation(s)
- Helena Crijns
- Laboratory of Molecular Immunology, Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, KU Leuven, Leuven, Belgium
| | - Vincent Vanheule
- Laboratory of Molecular Immunology, Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, KU Leuven, Leuven, Belgium
| | - Paul Proost
- Laboratory of Molecular Immunology, Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, KU Leuven, Leuven, Belgium
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4
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Gentile ME, Li Y, Robertson A, Shah K, Fontes G, Kaufmann E, Polese B, Khan N, Parisien M, Munter HM, Mandl JN, Diatchenko L, Divangahi M, King IL. NK cell recruitment limits tissue damage during an enteric helminth infection. Mucosal Immunol 2020; 13:357-370. [PMID: 31776431 PMCID: PMC7039810 DOI: 10.1038/s41385-019-0231-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Revised: 10/15/2019] [Accepted: 11/04/2019] [Indexed: 02/06/2023]
Abstract
Parasitic helminths cause significant damage as they migrate through host tissues to complete their life cycle. While chronic helminth infections are characterized by a well-described Type 2 immune response, the early, tissue-invasive stages are not well understood. Here we investigate the immune pathways activated during the early stages of Heligmosomoides polygyrus bakeri (Hpb), a natural parasitic roundworm of mice. In contrast to the Type 2 immune response present at later stages of infection, a robust Type 1 immune signature including IFNg production was dominant at the time of parasite invasion and granuloma formation. This early response was associated with an accumulation of activated Natural Killer (NK) cells, with no increase of other innate lymphoid cell populations. Parabiosis and confocal microscopy studies indicated that NK cells were recruited from circulation to the small intestine, where they surrounded parasitic larvae. NK cell recruitment required IFNγ receptor signaling, but was independent of CXCR3 expression. The depletion of tissue-infiltrating NK cells altered neither worm burden nor parasite fitness, but increased vascular injury, suggesting a role for NK cells in mediating tissue protection. Together, these data identify an unexpected role for NK cells in promoting disease tolerance during the invasive stage of an enteric helminth infection.
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Affiliation(s)
- Maria E Gentile
- Meakins-Christie Laboratories, Department of Medicine, McGill University Health Centre, Montreal, QC, H4A 3J1, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, QC, H3A 2B4, Canada
| | - Yue Li
- Meakins-Christie Laboratories, Department of Medicine, McGill University Health Centre, Montreal, QC, H4A 3J1, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, QC, H3A 2B4, Canada
| | - Amicha Robertson
- Department of Microbiology and Immunology, McGill University, Montreal, QC, H3A 2B4, Canada
- NYU Medical School, 550 First Avenue, New York, NY, 10016, USA
| | - Kathleen Shah
- Department of Microbiology and Immunology, McGill University, Montreal, QC, H3A 2B4, Canada
- Francis Crick Institute, 1 Midland Road, London, NW1 1AT, England
| | - Ghislaine Fontes
- Meakins-Christie Laboratories, Department of Medicine, McGill University Health Centre, Montreal, QC, H4A 3J1, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, QC, H3A 2B4, Canada
| | - Eva Kaufmann
- Meakins-Christie Laboratories, Department of Medicine, McGill University Health Centre, Montreal, QC, H4A 3J1, Canada
- McGill International TB Centre, McGill University Health Centre, Montreal, QC, H4A 3J1, Canada
| | - Barbara Polese
- Meakins-Christie Laboratories, Department of Medicine, McGill University Health Centre, Montreal, QC, H4A 3J1, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, QC, H3A 2B4, Canada
| | - Nargis Khan
- Meakins-Christie Laboratories, Department of Medicine, McGill University Health Centre, Montreal, QC, H4A 3J1, Canada
- McGill International TB Centre, McGill University Health Centre, Montreal, QC, H4A 3J1, Canada
| | - Marc Parisien
- Alan Edwards Centre for Research on Pain, Department of Anesthesia, McGill University, Montreal, QC, H3A 0G1, Canada
| | - Hans M Munter
- Department of Human Genetics, McGill University Innovation Centre, Montreal, QC, H3A 0G1, Canada
| | - Judith N Mandl
- Department of Physiology, Complex Traits Group, McGill University, Montreal, QC, H3G 0B1, Canada
| | - Luda Diatchenko
- Alan Edwards Centre for Research on Pain, Department of Anesthesia, McGill University, Montreal, QC, H3A 0G1, Canada
| | - Maziar Divangahi
- Meakins-Christie Laboratories, Department of Medicine, McGill University Health Centre, Montreal, QC, H4A 3J1, Canada
- Department of Microbiology and Immunology, McGill University, Montreal, QC, H3A 2B4, Canada
- McGill International TB Centre, McGill University Health Centre, Montreal, QC, H4A 3J1, Canada
| | - Irah L King
- Meakins-Christie Laboratories, Department of Medicine, McGill University Health Centre, Montreal, QC, H4A 3J1, Canada.
- Department of Microbiology and Immunology, McGill University, Montreal, QC, H3A 2B4, Canada.
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5
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Lord MS, Cheng B, Farrugia BL, McCarthy S, Whitelock JM. Platelet Factor 4 Binds to Vascular Proteoglycans and Controls Both Growth Factor Activities and Platelet Activation. J Biol Chem 2017; 292:4054-4063. [PMID: 28115521 DOI: 10.1074/jbc.m116.760660] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 01/18/2017] [Indexed: 11/06/2022] Open
Abstract
Platelet factor 4 (PF4) is produced by platelets with roles in both inflammation and wound healing. PF4 is stored in platelet α-granules bound to the glycosaminoglycan (GAG) chains of serglycin. This study revealed that platelet serglycin is decorated with chondroitin/dermatan sulfate and that PF4 binds to these GAG chains. Additionally, PF4 had a higher affinity for endothelial-derived perlecan heparan sulfate chains than serglycin GAG chains. The binding of PF4 to perlecan was found to inhibit both FGF2 signaling and platelet activation. This study revealed additional insight into the ways in which PF4 interacts with components of the vasculature to modulate cellular events.
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Affiliation(s)
- Megan S Lord
- From the Graduate School of Biomedical Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia and
| | - Bill Cheng
- From the Graduate School of Biomedical Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia and
| | - Brooke L Farrugia
- From the Graduate School of Biomedical Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia and
| | | | - John M Whitelock
- From the Graduate School of Biomedical Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia and
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6
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Madeeva D, Cines DB, Poncz M, Rauova L. Role of monocytes and endothelial cells in heparin-induced thrombocytopenia. Thromb Haemost 2016; 116:806-812. [PMID: 27487857 DOI: 10.1160/th16-02-0162] [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: 02/25/2016] [Accepted: 06/16/2016] [Indexed: 12/24/2022]
Abstract
Heparin-induced thrombocytopenia (HIT) is an autoimmune disorder characterised by thrombocytopenia and thrombosis. The mechanisms leading to platelet destruction are complex and the thrombotic complications of HIT appear to be due to multiple different intravascular targets. The dual binding of HIT antibodies to platelet surface PF4/GAG complexes and to FcγRIIA likely leads to both platelet clearance and to their direct activation. Monocytes and endothelial cells bind PF4 with higher avidity than platelets and are more resistant to competitive removal of surface-bound PF4 in the presence of heparin. Binding of HIT antibodies to PF4/glycosaminoglycan complexes on the surface on these cells leads to their activation and increased procoagulant activity. Binding of higher levels of PF4 released from activated platelets to the endothelium may lead to changes of the anticoagulant properties of the glycocalyx and target the endothelial cells for HIT antibodies. Pathogenic antibodies bound to endothelial cells further promote prothrombotic conditions by a mechanism that is independent of FcγR activation, yet not completely understood. A more detailed understanding of the role of monocytes and endothelium may identify new targets for intervention to mitigate the risk of thrombosis with less impact on systemic haemostasis than current approaches to treatment for this serious disorder.
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Affiliation(s)
| | | | | | - Lubica Rauova
- Lubica Rauova, MD, PhD, The Children's Hospital of Philadelphia, 3615 Civic Center Blvd, ARC, Rm. 316F, Philadelphia, PA 19104, USA, Tel.: +1 215 590 4667, Fax: +1 267 426 5476, E-mail:
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7
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Kowalska MA, Zhao G, Zhai L, David G, Marcus S, Krishnaswamy S, Poncz M. Modulation of Protein C Activation by Histones, Platelet Factor 4, and Heparinoids. Arterioscler Thromb Vasc Biol 2014; 34:120-6. [DOI: 10.1161/atvbaha.113.302236] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objective—
Histones are detrimental in late sepsis. Both activated protein C (aPC) and heparin can reverse their effect. Here, we investigated whether histones can modulate aPC generation in a manner similar to another positively charged molecule, platelet factor 4, and how heparinoids (unfractionated heparin or oxygen-desulfated unfractionated heparin with marked decrease anticoagulant activity) may modulate this effect.
Approach and Results—
We measured in vitro and in vivo effects of histones, platelet factor 4, and heparinoids on aPC formation, activated partial thromboplastin time, and murine survival. In vitro, histones and platelet factor 4 both affect thrombin/thrombomodulin aPC generation following a bell-shaped curve, with a peak of >5-fold enhancement. Heparinoids shift these curves rightward. Murine aPC generation studies after infusions of histones, platelet factor 4, and heparinoids supported the in vitro data. Importantly, although unfractionated heparin and 2-O, 3-O desulfated heparin both reversed the lethality of high-dose histone infusions, only mice treated with 2-O, 3-O desulfated heparin demonstrated corrected activated partial thromboplastin times and had significant levels of aPC.
Conclusions—
Our data provide a new contextual model of how histones affect aPC generation, and how heparinoid therapy may be beneficial in sepsis. These studies provide new insights into the complex interactions controlling aPC formation and suggest a novel therapeutic interventional strategy.
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Affiliation(s)
- M. Anna Kowalska
- From the Department of Pediatrics, The Children’s Hospital of Philadelphia, PA (M.A.K., G.Z., L.Z., G.D., S.K., M.P.); ParinGenix, Weston, FL (S.M.); and Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, PA (SK., M.P.)
| | - Guohua Zhao
- From the Department of Pediatrics, The Children’s Hospital of Philadelphia, PA (M.A.K., G.Z., L.Z., G.D., S.K., M.P.); ParinGenix, Weston, FL (S.M.); and Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, PA (SK., M.P.)
| | - Li Zhai
- From the Department of Pediatrics, The Children’s Hospital of Philadelphia, PA (M.A.K., G.Z., L.Z., G.D., S.K., M.P.); ParinGenix, Weston, FL (S.M.); and Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, PA (SK., M.P.)
| | - George David
- From the Department of Pediatrics, The Children’s Hospital of Philadelphia, PA (M.A.K., G.Z., L.Z., G.D., S.K., M.P.); ParinGenix, Weston, FL (S.M.); and Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, PA (SK., M.P.)
| | - Stephen Marcus
- From the Department of Pediatrics, The Children’s Hospital of Philadelphia, PA (M.A.K., G.Z., L.Z., G.D., S.K., M.P.); ParinGenix, Weston, FL (S.M.); and Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, PA (SK., M.P.)
| | - Sriram Krishnaswamy
- From the Department of Pediatrics, The Children’s Hospital of Philadelphia, PA (M.A.K., G.Z., L.Z., G.D., S.K., M.P.); ParinGenix, Weston, FL (S.M.); and Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, PA (SK., M.P.)
| | - Mortimer Poncz
- From the Department of Pediatrics, The Children’s Hospital of Philadelphia, PA (M.A.K., G.Z., L.Z., G.D., S.K., M.P.); ParinGenix, Weston, FL (S.M.); and Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, PA (SK., M.P.)
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8
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Abstract
Platelet factor 4 (CXCL4-PF4) is a chemokine that binds to and neutralizes heparin and other negatively charged proteoglycans, but is also involved in angiogenesis and cancer development. In some patients exposed to heparin, antibodies are generated against the CXCL-PF4/heparin complex that may activate platelets and coagulation and lead to thrombocytopenia and arterial or venous thrombosis, a condition commonly named heparin induced thrombocytopenia (HIT). HIT has been investigated in numerous clinical settings, but there is limited data on the epidemiology and phenotype of HIT in cancer patients. The present review describes the role of CXCL4-PF4 in cancer, the immunobiology, clinical presentation and diagnosis of HIT, and the specific problems faced in cancer patients.
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Affiliation(s)
- Per Morten Sandset
- Oslo University Hospital Rikshospitalet, Department of Haematology and Research Institute of Internal Medicine, and University of Oslo, Institute of Clinical Medicine, Oslo, Norway.
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9
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Weiler H. Multiple receptor-mediated functions of activated protein C. Hamostaseologie 2012; 31:185-95. [PMID: 21826371 DOI: 10.5482/ha-1166] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Accepted: 06/17/2011] [Indexed: 01/08/2023] Open
Abstract
The central effector protease of the protein C pathway, activated protein C (APC), interacts with the endothelial cell protein C receptor, with protease activated receptors (PAR), the apolipoprotein E2 receptor, and integrins to exert multiple effects on haemostasis and immune cell function. Such receptor interactions modify the activation of PC and determine the biological response to endogenous and therapeutically administered APC. This review summarizes the current knowledge about interactions of APC with cell surface-associated receptors, novel substrates such as histones and tissue factor pathway inhibitor, and their implications for the biologic function of APC in the control of coagulation and inflammation.
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Affiliation(s)
- H Weiler
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee WI 53226, USA.
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10
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Hashiguchi T, Mizumoto S, Nishimura Y, Tamura JI, Yamada S, Sugahara K. Involvement of human natural killer-1 (HNK-1) sulfotransferase in the biosynthesis of the GlcUA(3-O-sulfate)-Gal-Gal-Xyl tetrasaccharide found in α-thrombomodulin from human urine. J Biol Chem 2011; 286:33003-11. [PMID: 21828042 DOI: 10.1074/jbc.m111.279174] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Thrombomodulin (TM) is an integral membrane glycoprotein, which occurs as both a chondroitin sulfate (CS) proteoglycan (PG) form (β-TM) and a non-PG form without a CS chain (α-TM) and hence is a part-time PG. An α-TM preparation isolated from human urine contained the glycosaminoglycan linkage region tetrasaccharide GlcUAβ1-3Galβ1-3Galβ1-4xylose, and the nonreducing terminal GlcUA residue is 3-O-sulfated. Because the human natural killer-1 sulfotransferase (HNK-1ST) transfers a sulfate group from 3'-phosphoadenosine 5'-phosphosulfate to the C-3 position of the nonreducing terminal GlcUA residue in the HNK-1 antigen precursor trisaccharide, GlcUAβ1-3Galβ1-4GlcNAc, the sulfotransferase activity toward the linkage region was investigated. In fact, the activity of HNK-1ST toward the linkage region was much higher than that toward the glucuronylneolactotetraosylceramide, the precursor of the HNK-1 epitope. HNK-1ST may be responsible for regulating the sorting of α- and β-TM. Furthermore, HNK-1ST also transferred a sulfate group from 3'-phosphoadenosine 5'-phosphosulfate to the C-3 position of the nonreducing terminal GlcUA residue of a chondroitin chain. Intriguingly, the HNK-1 antibody recognized CS chains and the linkage region if they contained GlcUA(3-O-sulfate), suggesting that HNK-1ST not only synthesizes the HNK-1 epitope but may also be involved in the generation of part-time PGs.
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Affiliation(s)
- Taishi Hashiguchi
- Laboratory of Proteoglycan Signaling and Therapeutics, Frontier Research Center for Post-genomic Science and Technology, Graduate School of Life Science, Hokkaido University, West-11, North-21, Kita-ku, Sapporo, Hokkaido 001-0021, Japan
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11
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Antibodies associated with heparin-induced thrombocytopenia (HIT) inhibit activated protein C generation: new insights into the prothrombotic nature of HIT. Blood 2011; 118:2882-8. [PMID: 21772054 DOI: 10.1182/blood-2011-02-335208] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Heparin-induced thrombocytopenia (HIT) is caused by antibodies that recognize complexes between platelet factor 4 (PF4) and heparin or glycosaminoglycan side chains. These antibodies can lead to a limb- and life-threatening prothrombotic state. We now show that HIT antibodies are able to inhibit generation of activated protein C (aPC) by thrombin/thrombomodulin (IIa/TM) in the presence of PF4. Tetrameric PF4 potentiates aPC generation by formation of complexes with chondroitin sulfate (CS) on TM. Formation of these complexes occurs at a specific molar ratio of PF4 to glycosaminoglycan. This observation and the finding that the effect of heparin on aPC generation depends on the concentration of PF4 suggest similarity between PF4/CS complexes and those that bind HIT antibodies. HIT antibodies reduced the ability of PF4 to augment aPC formation. Cationic protamine sulfate, which forms similar complexes with heparin, also enhanced aPC generation, but its activity was not blocked by HIT antibodies. Our studies provide evidence that complexes formed between PF4 and TM's CS may play a physiologic role in potentiating aPC generation. Recognition of these complexes by HIT antibodies reverses the PF4-dependent enhancement in aPC generation and may contribute to the prothrombotic nature of HIT.
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Sarabi A, Kramp BK, Drechsler M, Hackeng TM, Soehnlein O, Weber C, Koenen RR, Von Hundelshausen P. CXCL4L1 inhibits angiogenesis and induces undirected endothelial cell migration without affecting endothelial cell proliferation and monocyte recruitment. J Thromb Haemost 2011; 9:209-19. [PMID: 20961394 DOI: 10.1111/j.1538-7836.2010.04119.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND AND OBJECTIVES The non-allelic variant of CXCL4/PF4, CXCL4L1/PF4alt, differs from CXCL4 in three amino acids of the C-terminal α-helix and has been characterized as a potent anti-angiogenic regulator. Although CXCL4 structurally belongs to the chemokine family, it does not behave like a 'classical' chemokine, lacking significant chemotactic properties. Specific hallmarks are its angiostatic, anti-proliferative activities, and proinflammatory functions, which can be conferred by heteromer-formation with CCL5/RANTES enhancing monocyte recruitment. METHODS AND RESULTS Here we show that tube formation of endothelial cells was inhibited by CXCL4L1 and CXCL4, while only CXCL4L1 triggered chemokinesis of endothelial cells. The chemotactic response towards VEGF and bFGF was attenuated by both variants and CXCL4L1-induced chemokinesis was blocked by bFGF or VEGF. Endothelial cell proliferation was inhibited by CXCL4 (IC(50) 6.9 μg mL(-1)) but not by CXCL4L1, while both chemokines bound directly to VEGF and bFGF. Moreover, CXCL4 enhanced CCL5-induced monocyte arrest in flow adhesion experiments and monocyte recruitment into the mouse peritoneal cavity in vivo, whereas CXCL4L1 had no effect. CXCL4L1 revealed lower affinity to CCL5 than CXCL4, as quantified by isothermal fluorescence titration. As evidenced by the reduction of the activated partial thromboplastin time, CXCL4L1 showed a tendency towards less heparin-neutralizing activity than CXCL4 (IC(50) 2.45 vs 0.98 μg mL(-1)). CONCLUSIONS CXCL4L1 may act angiostatically by causing random endothelial cell locomotion, disturbing directed migration towards angiogenic chemokines, serving as a homeostatic chemokine with a moderate structural distinction yet different functional profile from CXCL4.
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Affiliation(s)
- A Sarabi
- Institute for Cardiovascular Molecular Research, University Hospital Aachen, RWTH Aachen University, Aachen, Germany
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13
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The role of the CXC chemokines platelet factor-4 (CXCL4/PF-4) and its variant (CXCL4L1/PF-4var) in inflammation, angiogenesis and cancer. Cytokine Growth Factor Rev 2010; 22:1-18. [PMID: 21111666 DOI: 10.1016/j.cytogfr.2010.10.011] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Accepted: 10/28/2010] [Indexed: 02/07/2023]
Abstract
Chemokines are chemotactic cytokines which recruit leukocytes to inflammatory sites. They also affect tumor development and metastasis by acting as growth factor, by attracting pro- or anti-tumoral leukocytes or by influencing angiogenesis. Platelet factor-4 (CXCL4/PF-4) was the first chemokine shown to inhibit angiogenesis. CXCL4L1/PF-4var, recently isolated from thrombin-stimulated platelets, differing from authentic CXCL4/PF-4 in three carboxy-terminally located amino acids, was found to be more potent than CXCL4/PF-4 in inhibiting angiogenesis and tumor growth. Both glycosaminoglycans (GAG) and CXCR3 are implicated in the activities of the PF-4 variants. This report reviews the current knowledge on the role of CXCL4/PF-4 and CXCL4L1/PF-4var in physiological and pathological processes. In particular, the role of CXCL4/PF-4 in cancer, heparin-induced thrombocytopenia and atherosclerosis is described.
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14
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Mosnier LO. Platelet factor 4 inhibits thrombomodulin-dependent activation of thrombin-activatable fibrinolysis inhibitor (TAFI) by thrombin. J Biol Chem 2010; 286:502-10. [PMID: 21041299 DOI: 10.1074/jbc.m110.147959] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Thrombomodulin (TM) is a cofactor for thrombin-mediated activation of protein C and thrombin-activatable fibrinolysis inhibitor (TAFI) and thereby helps coordinate coagulation, anticoagulation, fibrinolysis, and inflammation. Platelet factor 4 (PF4), a platelet α-granule protein and a soluble cofactor for TM-dependent protein C activation, stimulates protein C activation in vitro and in vivo. In contrast to stimulation of protein C activation, PF4 is shown here to inhibit activation of TAFI by thrombin-TM. Consequences of inhibition of TAFI activation by PF4 included loss of TM-dependent prolongation of clot lysis times in hemophilia A plasma and loss of TM-stimulated conversion of bradykinin (BK) to des-Arg(9)-BK by TAFIa in normal plasma. Thus, PF4 modulates the substrate specificity of the thrombin-TM complex by selectively enhancing protein C activation while inhibiting TAFI activation, thereby preventing the generation of the antifibrinolytic and anti-inflammatory activities of TAFIa. To block the inhibitory effects of PF4 on TAFI activation, heparin derivatives were tested for their ability to retain high affinity binding to PF4 despite having greatly diminished anticoagulant activity. N-acetylated heparin (NAc-Hep) lacked detectable anticoagulant activity in activated partial thromboplastin time clotting assays but retained high affinity binding to PF4 and effectively reversed PF4 binding to immobilized TM. NAc-Hep permitted BK conversion to des-Arg(9)-BK by TAFIa in the presence of PF4. In a clot lysis assay on TM-expressing cells using hemophilia A plasma, NAc-Hep prevented PF4-mediated inhibition of TAFI activation and the antifibrinolytic functions of TAFIa. Accordingly, NAc-Hep or similar heparin derivatives might provide therapeutic benefits by diminishing bleeding complications in hemophilia A via restoration of TAFIa-mediated protection of clots against premature lysis.
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Affiliation(s)
- Laurent O Mosnier
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, USA.
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β2 Glycoprotein I (β2GPI) binds platelet factor 4 (PF4): implications for the pathogenesis of antiphospholipid syndrome. Blood 2010; 115:713-23. [DOI: 10.1182/blood-2009-03-206367] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Antiphospholipid syndrome (APS) is an autoimmune thrombophilia characterized by arterial/venous thrombosis and/or pregnancy morbidity in the presence of antiphospholipid antibodies that mainly recognize β2 glycoprotein I (β2GPI). To investigate potential platelet ligands of β2GPI, platelet membrane proteins from healthy persons and patients with APS were passed through a β2GPI-affinity column. By using mass spectrometry, platelet factor 4 (PF4) appeared as the dominant β2GPI binding protein. PF4 could bind in vitro, with high-affinity, recombinant β2GPI, and the binding was abrogated by soluble β2GPI. Coprecipitation experiments further confirmed this interaction. In silico molecular docking showed that PF4 tetramers can bind 2 β2GPI molecules simultaneously. Size exclusion chromatography confirmed that anti-β2GPI antibodies selectively interact with complexes composed of (β2GPI)2–(PF4)4. In addition, as shown by the β2GPI antigenicity evaluation, the reactivity of APS sera was higher against PF4–β2GPI complex than against β2GPI alone. On complex formation, anti-β2GPI–β2GPI–PF4 significantly induced platelet p38MAPK phosphorylation and TXB2 production, mainly through F(ab′)2 fragments of antibodies. In summary, this study makes evident that β2GPI forms stable complexes with PF4, leading to the stabilization of β2GPI dimeric structure that facilitates the antibody recognition. This interaction can probably be involved in the procoagulant tendency of APS.
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16
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Sandset PM. Immunobiology of Heparin-Induced Thrombocytopenia. Curr Top Microbiol Immunol 2010; 341:193-202. [DOI: 10.1007/82_2010_17] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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17
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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: 107] [Impact Index Per Article: 7.1] [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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18
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Preston RJS, Tran S, Johnson JA, Ní Áinle F, Harmon S, White B, Smith OP, Jenkins PV, Dahlbäck B, O'Donnell JS. Platelet factor 4 impairs the anticoagulant activity of activated protein C. J Biol Chem 2009; 284:5869-75. [PMID: 19129181 DOI: 10.1074/jbc.m804703200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Platelet factor 4 (PF4) is an abundant platelet alpha-granule chemokine released following platelet activation. PF4 interacts with thrombomodulin and the gamma-carboxyglutamic acid (Gla) domain of protein C, thereby enhancing activated protein C (APC) generation by the thrombin-thrombomodulin complex. However, the protein C Gla domain not only mediates protein C activation in vivo, but also plays a critical role in modulating the diverse functional properties of APC once generated. In this study we demonstrate that PF4 significantly inhibits APC anti-coagulant activity. PF4 inhibited both protein S-dependent APC anticoagulant function in plasma and protein S-dependent factor Va (FVa) proteolysis 3- to 5-fold, demonstrating that PF4 impairs protein S cofactor enhancement of APC anticoagulant function. Using recombinant factor Va variants FVa-R506Q/R679Q and FVa-R306Q/R679Q, PF4 was shown to impair APC proteolysis of FVa at position Arg(306) by 3-fold both in the presence and absence of protein S. These data suggest that PF4 contributes to the poorly understood APC resistance phenotype associated with activated platelets. Finally, despite PF4 binding to the APC Gla domain, we show that APC in the presence of PF4 retains its ability to initiate PAR-1-mediated cytoprotective signaling. In summary, we propose that PF4 acts as a critical regulator of APC generation, but also differentially targets APC toward cytoprotective, rather than anticoagulant function at sites of vascular injury with concurrent platelet activation.
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Affiliation(s)
- Roger J S Preston
- Haemostasis Research Group, Institute of Molecular Medicine, Trinity College Dublin, St James' Hospital, Dublin 8, Ireland.
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19
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A surface plasmon resonance-based solution affinity assay for heparan sulfate-binding proteins. Glycoconj J 2008; 26:577-87. [DOI: 10.1007/s10719-008-9210-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Revised: 10/05/2008] [Accepted: 10/27/2008] [Indexed: 12/15/2022]
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20
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Arepally GM, Poncz M, Cines DB. Immune Vascular Injury in Heparin-Induced Thrombocytopenia. HEPARIN-INDUCED THROMBOCYTOPENIA 2007. [DOI: 10.3109/9781420045093.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Lambert MP, Rauova L, Bailey M, Sola-Visner MC, Kowalska MA, Poncz M. Platelet factor 4 is a negative autocrine in vivo regulator of megakaryopoiesis: clinical and therapeutic implications. Blood 2007; 110:1153-60. [PMID: 17495129 PMCID: PMC1976471 DOI: 10.1182/blood-2007-01-067116] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Platelet factor 4 (PF4) is a negative regulator of megakaryopoiesis in vitro. We have now examined whether PF4 regulates megakaryopoiesis in vivo by studying PF4 knockout mice and transgenic mice that overexpress human (h) PF4. Steady-state platelet count and thrombocrit in these animals was inversely related to platelet PF4 content. Growth of megakaryocyte colonies was also inversely related to platelet PF4 content. Function-blocking anti-PF4 antibody reversed this inhibition of megakaryocyte colony growth, indicating the importance of local PF4 released from developing megakaryocytes. The effect of megakaryocyte damage and release of PF4 on 5-fluorouracil-induced marrow failure was then examined. Severity of thrombocytopenia and time to recovery of platelet counts were inversely related to initial PF4 content. Recovery was faster and more extensive, especially in PF4-overexpressing mice, after treatment with anti-PF4 blocking antibodies, suggesting a means to limit the duration of such a chemotherapy-induced thrombocytopenia, especially in individuals with high endogenous levels of PF4. We found that approximately 8% of 250 healthy adults have elevated (> 2 times average) platelet PF4 content. These individuals with high levels of platelet PF4 may be especially sensitive to developing thrombocytopenia after bone marrow injury and may benefit from approaches that block the effects of released PF4.
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Affiliation(s)
- Michele P Lambert
- Department of Pediatrics, Children's Hospital of Philadelphia, PA 19104, USA
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22
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Amelot AA, Tagzirt M, Ducouret G, Kuen RL, Le Bonniec BF. Platelet factor 4 (CXCL4) seals blood clots by altering the structure of fibrin. J Biol Chem 2006; 282:710-20. [PMID: 17090548 DOI: 10.1074/jbc.m606650200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Platelet factor-4 (PF4/CXCL4) is an orphan chemokine released in large quantities in the vicinity of growing blood clots. Coagulation of plasma supplemented with a matching amount of PF4 results in a translucent jelly-like clot. Saturating amounts of PF4 reduce the porosity of the fibrin network 4.4-fold and decrease the values of the elastic and loss moduli by 31- and 59-fold, respectively. PF4 alters neither the cleavage of fibrinogen by thrombin nor the cross-linking of protofibrils by activated factor XIII but binds to fibrin and dramatically transforms the structure of the ensuing network. Scanning electron microscopy showed that PF4 gives rise to a previously unreported pattern of polymerization where fibrin assembles to form a sealed network. The subunits constituting PF4 form a tetrahedron having at its corners a RPRH motif that mimics (in reverse orientation) the Gly-His-Arg-Pro-amide peptides that co-crystallize with fibrin. Molecular modeling showed that PF4 could be docked to fibrin with remarkable complementarities and absence of steric clashes, allowing the assembly of irregular polymers. Consistent with this hypothesis, as little as 50 microm the QVRPRHIT peptide derived from PF4 affects the polymerization of fibrin.
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23
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Mosnier LO, Bouma BN. Regulation of fibrinolysis by thrombin activatable fibrinolysis inhibitor, an unstable carboxypeptidase B that unites the pathways of coagulation and fibrinolysis. Arterioscler Thromb Vasc Biol 2006; 26:2445-53. [PMID: 16960106 DOI: 10.1161/01.atv.0000244680.14653.9a] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The coagulation and fibrinolytic systems safeguard the patency of the vasculature and surrounding tissue. Cross regulation of coagulation and fibrinolysis plays an important role in preserving a balanced hemostatic process. Identification of Thrombin Activatable Fibrinolysis Inhibitor (TAFI) as an inhibitor of fibrinolysis and one of the main intermediates between coagulation and fibrinolysis, greatly improved our understanding of cross regulation of coagulation and fibrinolysis. As TAFI is an enzyme that is activated by thrombin generated by the coagulation system, its activation is sensitive to the dynamics of the coagulation system. Defects in coagulation, such as in thrombosis or hemophilia, resonate in TAFI-mediated regulation of fibrinolysis and imply that clinical symptoms of coagulation defects are amplified by unbalanced fibrinolysis. Thrombomodulin promotes the generation of both antithrombotic activated protein C (APC) and prothrombotic (antifibrinolytic) activated TAFI, illustrating the paradoxical effects of thrombomodulin on the regulation of coagulation and fibrinolysis. This review will discuss the role of TAFI in the regulation of fibrinolysis and detail its regulation of activation and its potential therapeutic applications in thrombotic disease and bleeding disorders.
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Affiliation(s)
- Laurent O Mosnier
- The Scripps Research Institute, Department of Molecular and Experimental Medicine, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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24
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Tanaka KA, Szlam F, Levy JH. The effect of aprotinin on activated protein C-mediated downregulation of endogenous thrombin generation. Br J Haematol 2006; 134:77-82. [PMID: 16803571 DOI: 10.1111/j.1365-2141.2006.06099.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Thrombin plays a central role in coagulation and haemostasis. Binding of thrombin to thrombomodulin generates activated protein C (APC), which exerts a negative feedback on thrombin formation. Aprotinin, a natural proteinase inhibitor is used extensively during cardiac surgery because this procedure is often associated with profound activation of coagulation and inflammatory pathways. Some in vitro evidences suggest that aprotinin inhibits APC, but the clinical relevance is unclear. The recombinant human soluble thrombomodulin (rhsTM)-modified thrombin generation (TG) assay was used to investigate the effects of aprotinin on APC in plasma samples obtained from healthy volunteers, aprotinin-treated cardiac surgical patients and in protein C (PC)-depleted plasma. Based on the results of in vitro TG assay, addition of rhsTM (0.75-3.0 microg/ml) to volunteer or patient platelet-poor plasma significantly reduced (70.8 +/- 21.9 and 95.3% +/- 4.6%, respectively) thrombin formation when compared with PC-depleted plasma (8.3% +/- 5.2%). Aprotinin (100-200 KIU) caused a small, statistically insignificant decrease in the peak thrombin formation in normal and PC-deficient plasma (12.0 +/- 6.1%). In cardiac surgical patients, levels of functional PC, factor II, antithrombin and platelet significantly decreased after cardiopulmonary bypass (CPB). Soluble thrombomodulin concentrations were increased after CPB (3.5 +/- 2.2 to 5.0 +/- 2.2 ng/ml), but they were still within the normal range for human plasma. Our results showed that, even though endogenous PC level is decreased after CPB, it retains its activity in the presence of thrombomodulin, and aprotinin has limited inhibitory effect on APC generation.
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Affiliation(s)
- Kenichi A Tanaka
- Department of Anesthesiology, Emory University School of Medicine, Atlanta, GA, USA.
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25
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von Hundelshausen P, Koenen RR, Sack M, Mause SF, Adriaens W, Proudfoot AEI, Hackeng TM, Weber C. Heterophilic interactions of platelet factor 4 and RANTES promote monocyte arrest on endothelium. Blood 2005; 105:924-30. [PMID: 15459010 DOI: 10.1182/blood-2004-06-2475] [Citation(s) in RCA: 262] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
AbstractThe chemokines platelet factor 4 (PF4) and RANTES (regulated on activation normal T cell expressed and secreted) are secreted by activated platelets and influence multiple cell types and biologic processes. For instance, PF4 inhibits progenitor cell proliferation and angiogenesis, while platelet-derived RANTES is involved in vascular recruitment of monocytes. However, little is known about functional interactions of PF4 and RANTES. Here we show that the presence of PF4 enhanced the arrest of RANTES-stimulated monocytes and monocytic cells on activated endothelial cells under flow conditions, while binding of PF4 to the monocyte surface was increased by RANTES. Both RANTES-triggered arrest and PF4 binding involved monocytic chondroitin sulfate. Ligand blots and surface plasmon resonance revealed a robust heterophilic interaction of PF4 with RANTES but not with RANTES variants defective in higher order oligomerization. The tetrameric mutant E26A bound to the monocyte surface without increasing PF4 binding, and monocyte arrest induced by E26A-RANTES was not enhanced by PF4. Stimulation of monocytes with supernatants of activated platelets triggered arrest involving RANTES and PF4, as shown by inhibition studies. Our results suggest that heterophilic interactions with PF4 require structural motifs important in RANTES oligomerization and amplify RANTES-triggered effects on monocyte adhesion. This may have implications for the modulation of inflammatory recruitment by platelet-derived chemokines.
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Abstract
Platelet factor 4 (PF4) is a platelet alpha-granule protein sequenced over 25 years ago that is a founding member of the C-X-C chemokine family, yet its physiologic function has yet to be definitively established. Initial investigations focused on possible procoagulant roles for PF4 in platelet function and plasmatic coagulation. Subsequent in vitro studies have, however, described a puzzling array of other apparently unrelated biologic functions, including inhibition of angiogenesis and hematopoiesis, promotion of neutrophil adhesion, and activation, enhancement of oxy-LDL binding to the LDL receptor and stimulation of anti-coagulant activated protein C generation by the thrombomodulin/protein C system. Preliminary studies with a just-described PF4 knockout mouse line support a role for PF4 in platelet-dependent thrombosis in vivo.
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Abstract
The objective of this study was to review the mechanisms by which thrombomodulin (TM) may modulate inflammation. The data were taken from published research performed by other laboratories and our own experimental results. TM is a transmembrane glycoprotein receptor and cofactor for thrombin in the protein C anticoagulant system. Recent studies have revealed that TM has activities, both dependent and independent of either protein C or thrombin, that affect biological systems beyond the coagulation pathway. This review highlights recent insights, provided by in vitro and in vivo analyses, into how the unique structural domains of TM effectively modify coagulation, fibrinolysis, and inflammation in health and disease. A paradigm is presented to describe how these apparently distinct functions are integrated to maintain homeostasis under stress conditions. Finally, we explore the potential diagnostic and therapeutic utility of dissecting out the structure-function correlates of TM. We conclude that TM plays a central role in regulating not only hemostasis but also inflammation, thus providing a close link between these processes. Elucidation of the molecular mechanisms by which TM functions will likely provide novel targets for therapeutic intervention.
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Affiliation(s)
- Marlies Van de Wouwer
- Flanders Interuniversity Institute for Biotechnology and the Center for Transgene Technology and Gene Therapy, University of Leuven, Leuven, Belgium
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28
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Abstract
OBJECTIVE To review published studies of the influence of platelet factor 4 (PF4) and other cationic proteins on the generation of activated protein C (APC) by the thrombomodulin-protein C system. DATA SOURCE Using the PubMed citation index, literature published from 1973 to 2003 regarding cationic proteins, PF4, and the thrombomodulin-protein C system was reviewed. DATA SYNTHESIS All other cationic proteins studied to date either impair or do not affect APC generation via the thrombomodulin-protein C system; however, the platelet alpha-granule protein PF4 causes a 25-fold increase in the ability of thrombomodulin polypeptides to generate APC and a ten-fold increase in the ability of cultured endothelial cell-associated thrombomodulin to generate APC. The mechanism underlying this phenomenon depends on binding of the cationic PF4 to the anionic, vitamin K- dependent gamma-carboxyglutamic acid domain of protein C. The extent of PF4's stimulation of APC generation is further increased by its interaction with the anionic glycosaminoglycan moiety that is variably expressed through posttranslational, O-linked glycosylation of thrombomodulin. In an in vivo thrombin-infusion model of thrombomodulin activation in cynomolgus monkeys, previous intravenous infusion of pharmacologic amounts of PF4 resulted in circulating APC levels and APC-dependent prolongation of activated partial thromboplastin times that were two- to three-fold greater than those observed in saline-infused control animals. CONCLUSIONS These findings raise the possibility that PF4 plays a hitherto unsuspected physiologic role in enhancing APC generation in vivo. They also provide a rationale for considering the infusion of PF4 or PF4-related peptides or peptidomimetics as a way of beneficially stimulating "endogenous" APC generation from circulating protein C in pathologic human disease states such as sepsis.
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Affiliation(s)
- Arne Slungaard
- Department of Medicine, University of Minnesota, Minneapolis, MN, USA
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29
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Eslin DE, Zhang C, Samuels KJ, Rauova L, Zhai L, Niewiarowski S, Cines DB, Poncz M, Kowalska MA. Transgenic mice studies demonstrate a role for platelet factor 4 in thrombosis: dissociation between anticoagulant and antithrombotic effect of heparin. Blood 2004; 104:3173-80. [PMID: 14764524 DOI: 10.1182/blood-2003-11-3994] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The platelet-specific chemokine platelet factor 4 (PF4) is released in large amounts at sites of vascular injury. PF4 binds to heparin with high affinity, but its in vivo biologic role has not been defined. We studied the role of PF4 in thrombosis using heterozygote and homozygote PF4 knock-out mice (mPF4(+/-) and mPF4(-/-), respectively) and transgenic mice overexpressing human PF4 (hPF4(+)). None of these lines had an overt bleeding diathesis, but in a FeCl(3) carotid artery thrombosis model, all showed impaired thrombus formation. This defect in thrombus formation in the mPF4(-/-) animals was corrected by infusing hPF4 over a narrow concentration range. The thrombotic defect in the mPF4(+/-) and mPF4(-/-) animals was particularly sensitive to infusions of the negatively charged anticoagulant heparin. However, the same amount of heparin paradoxically normalized thrombus formation in the hPF4(+) animals, although these animals were anticoagulated systemically. Upon infusion of the positively charged protein, protamine sulfate, the reverse was observed with mPF4(+/-) and mPF4(-/-) animals having improved thrombosis, with the hPF4(+) animals having worsened thrombus formation. These studies support an important role for PF4 in thrombosis, and show that neutralization of PF4 is an important component of heparin's anticoagulant effect. The mechanisms underlying these observations of PF4 biology and their clinical implications remain to be determined.
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Affiliation(s)
- Don E Eslin
- Division of Hematology, The Children's Hospital of Philadelphia, 34th Street and Civic Center Blvd, ARC; Rm 316I, Philadelphia, PA 19104, USA
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Slungaard A, Fernandez JA, Griffin JH, Key NS, Long JR, Piegors DJ, Lentz SR. Platelet factor 4 enhances generation of activated protein C in vitro and in vivo. Blood 2003; 102:146-51. [PMID: 12609838 DOI: 10.1182/blood-2002-11-3529] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Platelet factor 4 (PF4), an abundant platelet alpha-granule protein, accelerates in vitro generation of activated protein C (APC) by soluble thrombin/thrombomodulin (TM) complexes up to 25-fold. To test the hypothesis that PF4 similarly stimulates endothelium-associated TM, we assessed the influence of human PF4 on thrombin-dependent APC generation by cultured endothelial monolayers. APC generated in the presence of 1 to 100 microg PF4 was up to 5-fold higher than baseline for human umbilical vein endothelial cells, 10-fold higher for microvascular endothelial cells, and unaltered for blood outgrowth endothelial cells. In an in vivo model, cynomolgus monkeys (n = 6, each serving as its own control) were infused with either PF4 (7.5 mg/kg) or vehicle buffer, then with human thrombin (1.0 microg/kg/min) for 10 minutes. Circulating APC levels (baseline 3 ng/mL) peaked at 10 minutes, when PF4-treated and vehicle-treated animals had APC levels of 67 +/- 5 ng/mL and 39 +/- 2 ng/mL, respectively (P <.001). The activated partial thromboplastin time (APTT; baseline, 28 seconds) increased maximally by 27 +/- 6 seconds in PF4-treated animals and by 9 +/- 1 seconds in control animals at 30 minutes (P <.001). PF4-dependent increases in circulating APC and APTT persisted more than 2-fold greater than that of controls from 10 through 120 minutes (P < or =.04). All APTT prolongations were essentially reversed by monoclonal antibody C3, which blocks APC activity. Thus, physiologically relevant concentrations of PF4 stimulate thrombin-dependent APC generation both in vitro by cultured endothelial cells and in vivo in a primate thrombin infusion model. These findings suggest that PF4 may play a previously unsuspected physiologic role in enhancing APC generation.
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Affiliation(s)
- Arne Slungaard
- Department of Medicine, Section of Hematology, Oncology and Transplantation, University of Minnesota, Mayo Mail Code 480, 420 Delaware St SE, Minneapolis, MN 55455, USA.
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31
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Dudek AZ, Nesmelova I, Mayo K, Verfaillie CM, Pitchford S, Slungaard A. Platelet factor 4 promotes adhesion of hematopoietic progenitor cells and binds IL-8: novel mechanisms for modulation of hematopoiesis. Blood 2003; 101:4687-94. [PMID: 12586630 DOI: 10.1182/blood-2002-08-2363] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Platelet factor 4 (PF4) is an abundant platelet alpha-granule C-X-C chemokine that has weak chemotactic potency but strongly inhibits hematopoiesis through an unknown mechanism. We find that PF4 binds to human CD34+ hematopoietic progenitor cells (HPCs) with a median effective concentration of 1 microg/mL but not after exposure to chondroitinase ABC. PF4 enhances adhesion of HPCs to intact stroma. Committed progenitors also adhere avidly to immobilized PF4. This adhesion is time-dependent, requires metabolic activity, causes cytoskeletal rearrangement, and induces cell-cycle inhibition. Using extracellular acidification rate to indicate transmembrane signaling, we find that interleukin-8 (IL-8), but not PF4, activates CD34+ progenitors, and PF4 blocks IL-8-mediated activation. Surface plasmon resonance analysis shows that PF4 binds IL-8 with high (dissociation constant [Kd] = 42 nM) affinity. Nuclear magnetic resonance analysis of IL-8 and PF4 in solution confirms this interaction. We conclude that PF4 has the capacity to influence hematopoiesis through mechanisms not mediated by a classical high-affinity, 7-transmembrane domain chemokine receptor. Instead, PF4 may modulate the hematopoietic milieu both directly, by promoting progenitor adhesion and quiescence through interaction with an HPC chondroitin sulfate-containing moiety, and indirectly, by binding to or interfering with signaling caused by other, hematopoietically active chemokines, such as IL-8.
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Affiliation(s)
- Arkadiusz Z Dudek
- Department of Medicine, Division of Hematology, Oncology, and Transplantation, Stem Cell Institute, Minneapolis, MN, USA.
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32
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Nassar T, Sachais BS, Akkawi S, Kowalska MA, Bdeir K, Leitersdorf E, Hiss E, Ziporen L, Aviram M, Cines D, Poncz M, Higazi AAR. Platelet factor 4 enhances the binding of oxidized low-density lipoprotein to vascular wall cells. J Biol Chem 2003; 278:6187-93. [PMID: 12466273 DOI: 10.1074/jbc.m208894200] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Accumulation of low-density lipoprotein (LDL)-derived cholesterol by macrophages in vessel walls is a pathogenomic feature of atherosclerotic lesions. Platelets contribute to lipid uptake by macrophages through mechanisms that are only partially understood. We have previously shown that platelet factor 4 (PF4) inhibits the binding and degradation of LDL through its receptor, a process that could promote the formation of oxidized LDL (ox-LDL). We have now characterized the effect of PF4 on the binding of ox-LDL to vascular cells and macrophages and on the accumulation of cholesterol esters. PF4 bound to ox-LDL directly and also increased ox-LDL binding to vascular cells and macrophages. PF4 did not stimulate ox-LDL binding to cells that do not synthesize glycosaminoglycans or after enzymatic cleavage of cell surface heparan and chondroitin sulfates. The effect of PF4 on binding ox-LDL was dependent on specific lysine residues in its C terminus. Addition of PF4 also caused an approximately 10-fold increase in the amount of ox-LDL esterified by macrophages. Furthermore, PF4 and ox-LDL co-localize in atherosclerotic lesion, especially in macrophage-derived foam cells. These observations offer a potential mechanism by which platelet activation at sites of vascular injury may promote the accumulation of deleterious lipoproteins and offer a new focus for pharmacological intervention in the development of atherosclerosis.
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Affiliation(s)
- Taher Nassar
- Department of Clinical Biochemistry, the Center for Research, Prevention, and Treatment of Atherosclerosis, Hadassah University Hospital and Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
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33
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Li ZQ, Liu W, Park KS, Sachais BS, Arepally GM, Cines DB, Poncz M. Defining a second epitope for heparin-induced thrombocytopenia/thrombosis antibodies using KKO, a murine HIT-like monoclonal antibody. Blood 2002; 99:1230-6. [PMID: 11830470 DOI: 10.1182/blood.v99.4.1230] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Heparin-induced thrombocytopenia/thrombosis (HIT/T) is a common complication of heparin therapy that is caused by antibodies to platelet factor 4 (PF4) complexed with heparin. The immune response is polyclonal and polyspecific, ie, more than one neoepitope on PF4 is recognized by HIT/T antibodies. One such epitope has been previously identified; it involves the domain between the third and fourth cysteine residues in PF4 (site 1). However, the binding sites for other HIT/T antibodies remain to be defined. To explore this issue, the binding site of KKO, an HIT/T-like murine monoclonal antibody, was defined. KKO shares a binding site with many HIT/T antibodies on PF4/heparin, but does not bind to site 1 or recognize mouse PF4/heparin. Therefore, the binding of KKO to a series of mouse/human PF4 chimeras complexed with heparin was examined. KKO recognizes a site that requires both the N terminus of PF4 and Pro34, which immediately precedes the third cysteine. Both regions lie on the surface of the PF4 tetramer in sufficient proximity (within 0.74 nm) to form a contiguous antigenic determinant. The 10 of 14 HIT/T sera that require the N terminus of PF4 for antigen recognition also require Pro34 to bind. This epitope, termed site 2, lies adjacent to site 1 in the crystal structure of the PF4 tetramer. Yet sites 1 and 2 can be recognized by distinct populations of antibodies. These studies further help to define a portion of the PF4 tetramer to which self-reactive antibodies develop in patients exposed to heparin.
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Affiliation(s)
- Zhong Q Li
- Department of Pathology, University of Pennsylvania School of Medicine, Philadelphia, USA
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Lin Y, Pixley RA, Colman RW. Kinetic analysis of the role of zinc in the interaction of domain 5 of high-molecular weight kininogen (HK) with heparin. Biochemistry 2000; 39:5104-10. [PMID: 10819977 DOI: 10.1021/bi992048z] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Previous investigations have shown that HK and its light chain bind heparin, preventing the enhancement of antithrombin inhibition of thrombin and potentiating the inhibition of plasma kallikrein by antithrombin. We found that both HK and HKa bound heparin, but HK exhibited a greater affinity. We therefore localized the binding sites for heparin on HK. HK domains 5 and 6 of the light chain as well as domain 3 from the heavy chain, expressed as glutathione S-transferase (GST) fusion proteins in Escherichia coli, were tested for binding to immobilized heparin by surface plasmon resonance using a BiaCore 2000 instrument. GST-D5, but not GST-D3, GST-D6, or GST, bound to heparin when the recombinant domains were present at a concentration of 70 nM. To localize more precisely the amino acid sequences on D5, both of the subdomains, histidine-glycine-rich GST-(K420-D474) and histidine-glycine-lysine-rich GST-(H475-S626), were expressed and tested for binding to immobilized heparin. The K(d) was much lower for GST-(K420-D474) than for GST-(H475-S626) in the presence or absence of Zn(2+). GST-(K420-D474) was effective in decreasing the rate of inactivation of thrombin by antithrombin in the presence of heparin and Zn(2+), while GST-(H475-S626) had no effect. We conclude that the binding of heparin to HK is a complex function of Zn(2+) interacting with histidines in the sequence K420-D474 to create high-affinity binding sites. HK has the potential to be an important modulator of heparin therapy.
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Affiliation(s)
- Y Lin
- Sol Sherry Thrombosis Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA
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35
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Abstract
Antibodies to PF4/heparin can be demonstrated in almost all patients with heparin-induced thrombocytopenia/thrombosis (HIT/HITT) and in some persons exposed to heparin who do not have clinical manifestations. The role of anti-PF4/heparin antibodies in the pathogenesis of HIT/HITT has been difficult to establish because the antibodies found in serum are generally polyclonal and polyspecific. To circumvent this problem, we developed a murine monoclonal antibody (mAb) to human (h) PF4/heparin complexes. A monoclonal IgG2bκ antibody (designated KKO) was identified that bound specifically to hPF4/heparin complexes. Maximal binding of KKO to hPF4/heparin complexes occurred at similar molar ratios of PF4:heparin observed for HIT/HITT antibodies. KKO also bound to hPF4 in association with other glycosaminoglycans. Platelet activation by KKO required heparin and was abrogated by blockade of FcγRIIA. In the presence of PF4, KKO bound to endothelial cells, but not to CHO cells lacking heparan sulfate proteoglycans. Variants of PF4 complexed to heparin were recognized equally well by KKO and HIT/HITT sera. KKO competes for binding with a subset of HIT/HITT antibodies that are relatively spared by mutations in the 3rd domain of PF4. The nucleotide and predicted amino acid sequences of KKO and RTO, a murine anti-hPF4 mAb that does not require heparin for binding, revealed no obvious relationship in either the heavy- or the light-chain immunoglobulin variable regions. These studies suggest that KKO recapitulates the antigenic and functional specificity of a subset of HIT/HITT antibodies and may, therefore, provide insight into the pathogenesis of thrombocytopenia and thrombosis in affected persons.
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36
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Petersen F, Brandt E, Lindahl U, Spillmann D. Characterization of a neutrophil cell surface glycosaminoglycan that mediates binding of platelet factor 4. J Biol Chem 1999; 274:12376-82. [PMID: 10212210 DOI: 10.1074/jbc.274.18.12376] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Platelet factor 4 (PF-4) is a platelet-derived alpha-chemokine that binds to and activates human neutrophils to undergo specific functions like exocytosis or adhesion. PF-4 binding has been shown to be independent of interleukin-8 receptors and could be inhibited by soluble chondroitin sulfate type glycosaminoglycans or by pretreatment of cells with chondroitinase ABC. Here we present evidence that surface-expressed neutrophil glycosaminoglycans are of chondroitin sulfate type and that this species binds to the tetrameric form of PF-4. The glycosaminoglycans consist of a single type of chain with an average molecular mass of approximately 23 kDa and are composed of approximately 85-90% chondroitin 4-sulfate disaccharide units type CSA (-->4GlcAbeta1-->3GalNAc(4-O-sulfate)beta1-->) and of approximately 10-15% di-O-sulfated disaccharide units. A major part of these di-O-sulfated disaccharide units are CSE units (-->4GlcAbeta1-->3GalNAc(4,6-O-sulfate)beta1-->). Binding studies revealed that the interaction of chondroitin sulfate with PF-4 required at least 20 monosaccharide units for significant binding. The di-O-sulfated disaccharide units in neutrophil glycosaminoglycans clearly promoted the affinity to PF-4, which showed a Kd approximately 0.8 microM, as the affinities of bovine cartilage chondroitin sulfate A, porcine skin dermatan sulfate, or bovine cartilage chondroitin sulfate C, all consisting exclusively of monosulfated disaccharide units, were found to be 3-5-fold lower. Taken together, our data indicate that chondroitin sulfate chains function as physiologically relevant binding sites for PF-4 on neutrophils and that the affinity of these chains for PF-4 is controlled by their degree of sulfation.
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Affiliation(s)
- F Petersen
- Department of Medical Biochemistry and Microbiology, Uppsala University, Biomedical Center, Box 575, S-75123 Uppsala, Sweden
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Wakabayashi H, Natsuka S, Mega T, Otsuki N, Isaji M, Naotsuka M, Koyama S, Kanamori T, Sakai K, Hase S. Novel proteoglycan linkage tetrasaccharides of human urinary soluble thrombomodulin, SO4-3GlcAbeta1-3Galbeta1-3(+/-Siaalpha2-6)Galbeta1-4Xyl. J Biol Chem 1999; 274:5436-42. [PMID: 10026155 DOI: 10.1074/jbc.274.9.5436] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
O-linked sugar chains with xylose as a reducing end linked to human urinary soluble thrombomodulin were studied. Sugar chains were liberated by hydrazinolysis followed by N-acetylation and tagged with 2-aminopyridine. Two fractions containing pyridylaminated Xyl as a reducing end were collected. Their structures were determined by partial acid hydrolysis, two-dimensional sugar mapping combined with exoglycosidase digestions, methylation analysis, mass spectrometry, and NMR as SO4-3GlcAbeta1-3Galbeta1-3(+/-Siaalpha2-6)Galbeta1+ ++-4Xyl. These sugar chains could bind to an HNK-1 monoclonal antibody. This is believed to be the first example of a proteoglycan linkage tetrasaccharide with glucuronic acid 3-sulfate and sialic acid.
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Affiliation(s)
- H Wakabayashi
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
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38
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Inhibition of Human Umbilical Vein Endothelial Cell Proliferation by the CXC Chemokine, Platelet Factor 4 (PF4), Is Associated With Impaired Downregulation of p21Cip1/WAF1. Blood 1999. [DOI: 10.1182/blood.v93.1.25] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Human PF4 is a heparin-binding chemokine known to be capable of inhibiting endothelial cell proliferation and angiogenesis. To explore the biological mechanisms responsible for this action, we investigated the effect of PF4 on epidermal growth factor (EGF)-stimulated human umbilical vein endothelial cells (HUVEC), a model system in which stimulation is essentially independent of interaction with cell-surface glycosaminoglycans. Based on previous findings that PF4 blocks endothelial cell cycle entry and progression into S phase, we studied the molecular mechanism(s) of PF4 interference with cell cycle machinery. PF4 treatment of EGF-stimulated HUVEC caused a decrease in cyclin E–cyclin-dependent kinase 2 (cdk2) activity with resulting attenuation of retinoblastoma protein phosphorylation. PF4-dependent downregulation of cyclin E-cdk2 activity was associated with increased binding of the cyclin-dependent kinase inhibitor, p21Cip1/WAF1, to the cyclin E-cdk2 complex. Analysis of total cellular p21Cip1/WAF1 showed that in the presence of PF4, p21Cip1/WAF1 levels were sustained at time points when p21Cip1/WAF1 was no longer detectable in cells stimulated by EGF in the absence of PF4. These findings indicate that PF4 inhibition of HUVEC proliferation in response to EGF is associated with impaired downregulation of p21Cip1/WAF1 and provide the first evidence for interference with cell cycle mechanisms by a chemokine.
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39
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Inhibition of Human Umbilical Vein Endothelial Cell Proliferation by the CXC Chemokine, Platelet Factor 4 (PF4), Is Associated With Impaired Downregulation of p21Cip1/WAF1. Blood 1999. [DOI: 10.1182/blood.v93.1.25.401a47_25_33] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human PF4 is a heparin-binding chemokine known to be capable of inhibiting endothelial cell proliferation and angiogenesis. To explore the biological mechanisms responsible for this action, we investigated the effect of PF4 on epidermal growth factor (EGF)-stimulated human umbilical vein endothelial cells (HUVEC), a model system in which stimulation is essentially independent of interaction with cell-surface glycosaminoglycans. Based on previous findings that PF4 blocks endothelial cell cycle entry and progression into S phase, we studied the molecular mechanism(s) of PF4 interference with cell cycle machinery. PF4 treatment of EGF-stimulated HUVEC caused a decrease in cyclin E–cyclin-dependent kinase 2 (cdk2) activity with resulting attenuation of retinoblastoma protein phosphorylation. PF4-dependent downregulation of cyclin E-cdk2 activity was associated with increased binding of the cyclin-dependent kinase inhibitor, p21Cip1/WAF1, to the cyclin E-cdk2 complex. Analysis of total cellular p21Cip1/WAF1 showed that in the presence of PF4, p21Cip1/WAF1 levels were sustained at time points when p21Cip1/WAF1 was no longer detectable in cells stimulated by EGF in the absence of PF4. These findings indicate that PF4 inhibition of HUVEC proliferation in response to EGF is associated with impaired downregulation of p21Cip1/WAF1 and provide the first evidence for interference with cell cycle mechanisms by a chemokine.
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40
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Nadanaka S, Kitagawa H, Sugahara K. Demonstration of the immature glycosaminoglycan tetrasaccharide sequence GlcAbeta1-3Galbeta1-3Galbeta1-4Xyl on recombinant soluble human alpha-thrombomodulin. An oligosaccharide structure on a "part-time" proteoglycan. J Biol Chem 1998; 273:33728-34. [PMID: 9837960 DOI: 10.1074/jbc.273.50.33728] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Thrombomodulin (TM), a cell surface glycoprotein, is a critical mediator of endothelial anticoagulant defenses occurring both as a chondroitin sulfate proteoglycan (beta-TM) and a protein (alpha-TM) unsubstituted by chondroitin sulfate (CS), hence its description as a "part-time" proteoglycan (PG) (Fransson, L. A. (1987) Trends Biochem. Sci. 12, 406-411). Sugar analysis was performed on alpha-TM to investigate a possible biosynthetic mechanism for part-time PGs. Recombinant human alpha-TM, which was expressed in CHO-K1 cells, separated by anion-exchange chromatography from beta-TM, and purified by immunoaffinity chromatography (Nawa, K., Sakano, K., Fujiwara, H., Sato, Y., Sugiyama, N., Teruuchi, T., Iwamoto, M., and Marumoto, Y. (1990) Biochem. Biophys. Res. Commun. 171, 729-737), was used for analysis. Preliminary sugar composition analysis after acid hydrolysis showed Xyl in addition to Gal, GalNAc, GlcNAc, Man, Fuc, and Glc. O-Glycosidically-linked oligosaccharides were liberated by mild alkaline treatment and purified. The isolated oligosaccharide fraction was derivatized with a fluorophore 2-aminobenzamide (2AB), resulting in two fluorescent components, a 2AB-oligosaccharide and a putative 2AB-Glc. Based on structural analysis by a combination of sequential exoglycosidase digestion and 500-MHz 1H NMR spectroscopy of the 2AB-oligosaccharide, the structure of the oligosaccharide was elucidated as GlcAbeta1-3Galbeta1-3Galbeta1-4Xyl, which turned out to represent a glycosaminoglycan (GAG)-protein linkage region tetrasaccharide common to various PGs and was considered to be a biosynthetic intermediate of an immature GAG chain. The results may indicate that at least one class of the so-called part-time PGs bear the linkage tetrasaccharide at the GAG attachment sites and that the critical determining step or the rate-limiting step for PG biosynthesis is the transfer of the fifth sugar residue, the first hexosamine, rather than xylose.
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Affiliation(s)
- S Nadanaka
- Department of Biochemistry, Kobe Pharmaceutical University, Higashinada-ku, Kobe 658-8558, Japan
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