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Vautrinot J, Poole AW. Platelets tell old red cells to clear off. Blood 2024; 143:480-481. [PMID: 38329776 DOI: 10.1182/blood.2023023164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2024] Open
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2
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Agbani EO, Young D, Chen SA, Smith S, Lee A, Poole AW, Dufour A, Poon MC. Membrane procoagulation and N‑terminomics/TAILS profiling in Montreal platelet syndrome kindred with VWF p.V1316M mutation. Commun Med (Lond) 2023; 3:125. [PMID: 37735203 PMCID: PMC10514327 DOI: 10.1038/s43856-023-00354-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 09/06/2023] [Indexed: 09/23/2023] Open
Abstract
BACKGROUND The Montreal platelet syndrome kindred (MPS) with VWF p.V1316M mutation (2B-VWDMPS) is an extremely rare disorder. It has been associated with macrothrombocytopenia, spontaneous platelet clumping, mucocutaneous, and other bleeding, which can be largely prevented by von Willebrand factor (VWF) concentrate infusion. However, supplemental platelet transfusion has been required on occasion, particularly for severe gastrointestinal bleeds. This raised the question of whether a previously uncharacterized platelet dysfunction contributes to bleeding diathesis in 2B-VWDMPS patients. We have previously shown that membrane ballooning, a principal part of the platelet procoagulant membrane dynamics (PMD) after collagen stimulation, is driven by the influx of Na+ and Cl-, followed by the entry of water. METHODS We study two members (mother and daughter) of the MPS kindred with severe bleeding phenotype and address this question by coupling quantitative platelet shotgun proteomics and validating biochemical assays, with the systematic analysis of platelet procoagulant membrane dynamics (PMD). Using N-terminomics/TAILS (terminal amine isotopic labeling of substrates), we compare changes in proteolysis between healthy and 2B-VWDMPS platelets. RESULTS Here, we report in 2B-VWDMPS platelets, the loss of the transmembrane chloride channel-1 (CLIC1), and reduced chloride ion influx after collagen stimulation. This was associated with diminished membrane ballooning, phosphatidylserine externalization, and membrane thrombin formation, as well as a distinct phenotypic composition of platelets over fibrillar collagen. We also identify processing differences of VWF, fibronectin (FN1), and Crk-like protein (CRKL). 2B-VWDMPS platelets are shown to be basally activated, partially degranulated, and have marked loss of regulatory, cytoskeletal, and contractile proteins. CONCLUSIONS This may account for structural disorganization, giant platelet formation, and a weakened hemostatic response.
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Affiliation(s)
- Ejaife O Agbani
- Department of Physiology & Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.
- Libin Cardiovascular Institute, University of Calgary, Calgary, AB, Canada.
| | - Daniel Young
- McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, AB, Canada
| | - Si An Chen
- McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, AB, Canada
| | - Sophie Smith
- McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, AB, Canada
| | - Adrienne Lee
- Division of Hematology, Department of Medicine/Medical Oncology, University of British Columbia, Island Health, Victoria, BC, Canada
| | - Alastair W Poole
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, England, UK
| | - Antoine Dufour
- Department of Physiology & Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.
- McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, AB, Canada.
| | - Man-Chiu Poon
- Division of Hematology & Hematological Malignancies, Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.
- Departments of Pediatrics and Oncology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.
- Arnie Charbonneau Cancer Institute, University of Calgary, Calgary, AB, Canada.
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Zhao X, Alibhai D, Walsh TG, Tarassova N, Englert M, Birol SZ, Li Y, Williams CM, Neal CR, Burkard P, Cross SJ, Aitken EW, Waller AK, Beltrán JB, Gunning PW, Hardeman EC, Agbani EO, Nieswandt B, Hers I, Ghevaert C, Poole AW. Highly efficient platelet generation in lung vasculature reproduced by microfluidics. Nat Commun 2023; 14:4026. [PMID: 37419900 PMCID: PMC10329040 DOI: 10.1038/s41467-023-39598-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 06/20/2023] [Indexed: 07/09/2023] Open
Abstract
Platelets, small hemostatic blood cells, are derived from megakaryocytes. Both bone marrow and lung are principal sites of thrombopoiesis although underlying mechanisms remain unclear. Outside the body, however, our ability to generate large number of functional platelets is poor. Here we show that perfusion of megakaryocytes ex vivo through the mouse lung vasculature generates substantial platelet numbers, up to 3000 per megakaryocyte. Despite their large size, megakaryocytes are able repeatedly to passage through the lung vasculature, leading to enucleation and subsequent platelet generation intravascularly. Using ex vivo lung and an in vitro microfluidic chamber we determine how oxygenation, ventilation, healthy pulmonary endothelium and the microvascular structure support thrombopoiesis. We also show a critical role for the actin regulator Tropomyosin 4 in the final steps of platelet formation in lung vasculature. This work reveals the mechanisms of thrombopoiesis in lung vasculature and informs approaches to large-scale generation of platelets.
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Affiliation(s)
- Xiaojuan Zhao
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK.
| | - Dominic Alibhai
- Wolfson BioimagingFacility, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Tony G Walsh
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Nathalie Tarassova
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Maximilian Englert
- University Hospital and Rudolf Virchow Center, University of Würzburg, Würzburg, D-97080, Germany
| | - Semra Z Birol
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Yong Li
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Christopher M Williams
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Chris R Neal
- Wolfson BioimagingFacility, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Philipp Burkard
- University Hospital and Rudolf Virchow Center, University of Würzburg, Würzburg, D-97080, Germany
| | - Stephen J Cross
- Wolfson BioimagingFacility, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Elizabeth W Aitken
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Amie K Waller
- University of Cambridge / NHS Blood and Transplant, Wellcome-MRC Cambridge Stem Cell Institute, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge, CB2 0AW, UK
| | - José Ballester Beltrán
- University of Cambridge / NHS Blood and Transplant, Wellcome-MRC Cambridge Stem Cell Institute, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge, CB2 0AW, UK
| | - Peter W Gunning
- School of Medical Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Edna C Hardeman
- School of Medical Sciences, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Ejaife O Agbani
- Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Bernhard Nieswandt
- University Hospital and Rudolf Virchow Center, University of Würzburg, Würzburg, D-97080, Germany
| | - Ingeborg Hers
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Cedric Ghevaert
- University of Cambridge / NHS Blood and Transplant, Wellcome-MRC Cambridge Stem Cell Institute, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge, CB2 0AW, UK
| | - Alastair W Poole
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK.
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4
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Agbani EO, Chow L, Nicholas J, Skeith L, Schneider P, Gregory A, Mahe E, Yamaura L, Young D, Dufour A, Paul PP, Walker AM, Mukherjee PG, Poole AW, Poon MC, Lee A. Overexpression of facilitative glucose transporter-3 and membrane procoagulation in maternal platelets of preeclamptic pregnancy. J Thromb Haemost 2023; 21:1903-1919. [PMID: 36963633 DOI: 10.1016/j.jtha.2023.03.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 01/19/2023] [Accepted: 03/03/2023] [Indexed: 03/26/2023]
Abstract
BACKGROUND Preeclampsia (PE) is a hypertensive disorder during pregnancy that results in significant adverse maternal and neonatal outcomes. Platelet activation is present in PE and contributes to the thrombo-hemorrhagic states of the disorder. However, the mechanisms that initiate and/or sustain platelet activation in PE are ill-defined. OBJECTIVES We aimed to characterise this mechanism and the procoagulant potentials of platelets in PE. METHODS In this quantitative observational study, we analyzed platelet procoagulant membrane dynamics in patients with PE (n = 21) compared with age-matched normotensive pregnancies (n = 20), gestational hypertension (n = 10), and non-pregnant female controls (n = 19). We analyzed fluorescently labeled indicators of platelet activation, bioenergetics, and procoagulation (phosphatidylserine exposure and thrombin generation), coupled with high-resolution imaging and thrombelastography. We then validated our findings using flow cytometry, immunoassays, classical pharmacology, and convolutional neural network analysis. RESULTS PE platelets showed significant ultra-structural remodeling, are more extensively preactivated than in healthy pregnancies and can circulate as microaggregates. Preactivated platelets of PE externalized phosphatidylserine and thrombin formed on the platelet membranes. Platelets' expression of facilitative glucose transporter-1 increased in all pregnant groups. However, PE platelets additionally overexpress glucose transporter-3 to enhance glucose uptake and sustain activation and secretion events. Although preeclampsia platelets exposed to subendothelial collagen showed incremental activation, the absolute hemostatic response to collagen was diminished, and likely contributed to greater blood loss perioperatively. CONCLUSIONS We revealed 2 bioenergetic mediators in the mechanism of sustained platelet procoagulation in preeclampsia. Although glucose transporter-1 and glucose transporter-3 remain elusive antiprocoagulant targets, they may be sensitive monitors of PE onset and progression.
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Affiliation(s)
- Ejaife O Agbani
- Department of Physiology & Pharmacology, Cumming School of Medicine, University of Calgary, Alberta, Canada; Libin Cardiovascular Institute, Calgary, Alberta, Canada.
| | - Lorraine Chow
- Department of Anaesthesiology, Perioperative and Pain Medicine, Cumming School of Medicine, University of Calgary, Alberta, Canada
| | - Joshua Nicholas
- Department of Anaesthesiology, Perioperative and Pain Medicine, Cumming School of Medicine, University of Calgary, Alberta, Canada
| | - Leslie Skeith
- Libin Cardiovascular Institute, Calgary, Alberta, Canada; Division of Hematology & Hematological Malignancies, Department of Medicine, Cumming School of Medicine, University of Calgary, Alberta, Canada
| | - Prism Schneider
- Department of Surgery, Cumming School of Medicine, University of Calgary, Alberta, Canada; McCaig Institute for Bone and Joint Health, University of Calgary, Alberta, Canada
| | - Alexander Gregory
- Libin Cardiovascular Institute, Calgary, Alberta, Canada; Department of Anaesthesiology, Perioperative and Pain Medicine, Cumming School of Medicine, University of Calgary, Alberta, Canada
| | - Etienne Mahe
- Division of Hematology & Hematological Malignancies, Department of Medicine, Cumming School of Medicine, University of Calgary, Alberta, Canada; Department of Pathology & Laboratory Medicine, University of Calgary, Alberta, Canada
| | - Lisa Yamaura
- Department of Surgery, Cumming School of Medicine, University of Calgary, Alberta, Canada; McCaig Institute for Bone and Joint Health, University of Calgary, Alberta, Canada
| | - Daniel Young
- McCaig Institute for Bone and Joint Health, University of Calgary, Alberta, Canada
| | - Antoine Dufour
- Department of Physiology & Pharmacology, Cumming School of Medicine, University of Calgary, Alberta, Canada; McCaig Institute for Bone and Joint Health, University of Calgary, Alberta, Canada
| | - Padma Polash Paul
- Braintoy Inc Calgary and Computational Neuroscience Lab, University of Oxford, England, United Kingdom
| | - Andrew M Walker
- Department of Anaesthesiology, Perioperative and Pain Medicine, Cumming School of Medicine, University of Calgary, Alberta, Canada
| | | | - Alastair W Poole
- School of Physiology, Pharmacology, and Neuroscience, University of Bristol, England, United Kingdom
| | - Man-Chiu Poon
- Division of Hematology & Hematological Malignancies, Department of Medicine, Cumming School of Medicine, University of Calgary, Alberta, Canada; Arnie Charbonneau Cancer Institute, Calgary, Alberta, Canada
| | - Adrienne Lee
- Division of Hematology & Hematological Malignancies, Department of Medicine, Cumming School of Medicine, University of Calgary, Alberta, Canada; Division of Hematology, Department of Medicine/Medical Oncology, University of British Columbia, Island Health, Victoria, Canada
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5
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Trory JS, Munkacsi A, Śledź KM, Vautrinot J, Goudswaard LJ, Jackson ML, Heesom KJ, Moore SF, Poole AW, Nabet B, Aggarwal VK, Hers I. Chemical degradation of BTK/TEC as a novel approach to inhibit platelet function. Blood Adv 2023; 7:1692-1696. [PMID: 36342848 PMCID: PMC10182296 DOI: 10.1182/bloodadvances.2022008466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 11/02/2022] [Accepted: 11/03/2022] [Indexed: 11/09/2022] Open
Affiliation(s)
- Justin S. Trory
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Biomedical Sciences Building, Bristol BS8 1TD, United Kingdom
| | - Attila Munkacsi
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Biomedical Sciences Building, Bristol BS8 1TD, United Kingdom
| | - Kamila M. Śledź
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Biomedical Sciences Building, Bristol BS8 1TD, United Kingdom
| | - Jordan Vautrinot
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Biomedical Sciences Building, Bristol BS8 1TD, United Kingdom
| | - Lucy J. Goudswaard
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Biomedical Sciences Building, Bristol BS8 1TD, United Kingdom
- Bristol Medical School, Population Health Sciences, University of Bristol, Oakfield House, Bristol, United Kingdom
| | - Molly L. Jackson
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Biomedical Sciences Building, Bristol BS8 1TD, United Kingdom
| | - Kate J. Heesom
- Faculty of Life Sciences, Proteomics Facility, University of Bristol, University Walk, Biomedical Sciences Building, Bristol, United Kingdom
| | - Samantha F. Moore
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Biomedical Sciences Building, Bristol BS8 1TD, United Kingdom
| | - Alastair W. Poole
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Biomedical Sciences Building, Bristol BS8 1TD, United Kingdom
| | - Behnam Nabet
- Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA
| | - Varinder K. Aggarwal
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol, United Kingdom
| | - Ingeborg Hers
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Biomedical Sciences Building, Bristol BS8 1TD, United Kingdom
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6
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Agbani EO, Hers I, Poole AW. Platelet procoagulant membrane dynamics: a key distinction between thrombosis and hemostasis? Blood Adv 2023; 7:1615-1619. [PMID: 36574232 PMCID: PMC10173732 DOI: 10.1182/bloodadvances.2022008122] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 12/20/2022] [Accepted: 12/21/2022] [Indexed: 12/28/2022] Open
Affiliation(s)
- Ejaife O. Agbani
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Ingeborg Hers
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Alastair W. Poole
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
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7
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Goudswaard LJ, Williams CM, Khalil J, Burley KL, Hamilton F, Arnold D, Milne A, Lewis PA, Heesom KJ, Mundell SJ, Davidson AD, Poole AW, Hers I. Alterations in platelet proteome signature and impaired platelet integrin α IIbβ 3 activation in patients with COVID-19. J Thromb Haemost 2023; 21:1307-1321. [PMID: 36716966 PMCID: PMC9883069 DOI: 10.1016/j.jtha.2023.01.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 01/18/2023] [Accepted: 01/19/2023] [Indexed: 01/30/2023]
Abstract
BACKGROUND Patients with COVID-19 are at increased risk of thrombosis, which is associated with altered platelet function and coagulopathy, contributing to excess mortality. OBJECTIVES To characterize the mechanism of altered platelet function in COVID-19 patients. METHODS The platelet proteome, platelet functional responses, and platelet-neutrophil aggregates were compared between patients hospitalized with COVID-19 and healthy control subjects using tandem mass tag proteomic analysis, Western blotting, and flow cytometry. RESULTS COVID-19 patients showed a different profile of platelet protein expression (858 altered of the 5773 quantified). Levels of COVID-19 plasma markers were enhanced in the platelets of COVID-19 patients. Gene ontology pathway analysis demonstrated that the levels of granule secretory proteins were raised, whereas those of platelet activation proteins, such as the thrombopoietin receptor and protein kinase Cα, were lowered. Basally, platelets of COVID-19 patients showed enhanced phosphatidylserine exposure, with unaltered integrin αIIbβ3 activation and P-selectin expression. Agonist-stimulated integrin αIIbβ3 activation and phosphatidylserine exposure, but not P-selectin expression, were decreased in COVID-19 patients. COVID-19 patients had high levels of platelet-neutrophil aggregates, even under basal conditions, compared to controls. This association was disrupted by blocking P-selectin, demonstrating that platelet P-selectin is critical for the interaction. CONCLUSIONS Overall, our data suggest the presence of 2 platelet populations in patients with COVID-19: one of circulating platelets with an altered proteome and reduced functional responses and another of P-selectin-expressing neutrophil-associated platelets. Platelet-driven thromboinflammation may therefore be one of the key factors enhancing the risk of thrombosis in COVID-19 patients.
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Affiliation(s)
- Lucy J Goudswaard
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University Walk, Bristol, BS8 1TD, UK; Population Health Sciences, Oakfield House, Oakfield Grove, Bristol, BS8 2BN, UK. https://twitter.com/lucygoudswaard
| | - Christopher M Williams
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University Walk, Bristol, BS8 1TD, UK
| | - Jawad Khalil
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University Walk, Bristol, BS8 1TD, UK
| | - Kate L Burley
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University Walk, Bristol, BS8 1TD, UK
| | - Fergus Hamilton
- Population Health Sciences, Oakfield House, Oakfield Grove, Bristol, BS8 2BN, UK; Department of Infection Sciences, North Bristol NHS Trust, Bristol, BS10 5NB, UK
| | - David Arnold
- Academic Respiratory Unit, North Bristol NHS Trust, Bristol, BS10 5NB, UK
| | - Alice Milne
- Academic Respiratory Unit, North Bristol NHS Trust, Bristol, BS10 5NB, UK
| | - Phil A Lewis
- Proteomics Facility, Faculty of Life Sciences, University Walk, University of Bristol, Bristol, BS8 1TD, UK
| | - Kate J Heesom
- Proteomics Facility, Faculty of Life Sciences, University Walk, University of Bristol, Bristol, BS8 1TD, UK
| | - Stuart J Mundell
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University Walk, Bristol, BS8 1TD, UK
| | - Andrew D Davidson
- School of Cellular and Molecular Medicine, Biomedical Sciences Building, University Walk, Bristol, BS8 1TD, UK
| | - Alastair W Poole
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University Walk, Bristol, BS8 1TD, UK
| | - Ingeborg Hers
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University Walk, Bristol, BS8 1TD, UK.
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8
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Corbin LJ, White SJ, Taylor AE, Williams CM, Taylor K, van den Bosch MT, Teasdale JE, Jones M, Bond M, Harper MT, Falk L, Groom A, Hazell GG, Paternoster L, Munafò MR, Nordestgaard BG, Tybjærg-Hansen A, Bojesen SE, Relton C, Min JL, Davey Smith G, Mumford AD, Poole AW, Timpson NJ. Epigenetic Regulation of F2RL3 Associates With Myocardial Infarction and Platelet Function. Circ Res 2022; 130:384-400. [PMID: 35012325 PMCID: PMC8812435 DOI: 10.1161/circresaha.121.318836] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 12/30/2021] [Accepted: 01/04/2022] [Indexed: 11/24/2022]
Abstract
BACKGROUND DNA hypomethylation at the F2RL3 (F2R like thrombin or trypsin receptor 3) locus has been associated with both smoking and atherosclerotic cardiovascular disease; whether these smoking-related associations form a pathway to disease is unknown. F2RL3 encodes protease-activated receptor 4, a potent thrombin receptor expressed on platelets. Given the role of thrombin in platelet activation and the role of thrombus formation in myocardial infarction, alterations to this biological pathway could be important for ischemic cardiovascular disease. METHODS We conducted multiple independent experiments to assess whether DNA hypomethylation at F2RL3 in response to smoking is associated with risk of myocardial infarction via changes to platelet reactivity. Using cohort data (N=3205), we explored the relationship between smoking, DNA hypomethylation at F2RL3, and myocardial infarction. We compared platelet reactivity in individuals with low versus high DNA methylation at F2RL3 (N=41). We used an in vitro model to explore the biological response of F2RL3 to cigarette smoke extract. Finally, a series of reporter constructs were used to investigate how differential methylation could impact F2RL3 gene expression. RESULTS Observationally, DNA methylation at F2RL3 mediated an estimated 34% of the smoking effect on increased risk of myocardial infarction. An association between methylation group (low/high) and platelet reactivity was observed in response to PAR4 (protease-activated receptor 4) stimulation. In cells, cigarette smoke extract exposure was associated with a 4.9% to 9.3% reduction in DNA methylation at F2RL3 and a corresponding 1.7-(95% CI, 1.2-2.4, P=0.04) fold increase in F2RL3 mRNA. Results from reporter assays suggest the exon 2 region of F2RL3 may help control gene expression. CONCLUSIONS Smoking-induced epigenetic DNA hypomethylation at F2RL3 appears to increase PAR4 expression with potential downstream consequences for platelet reactivity. Combined evidence here not only identifies F2RL3 DNA methylation as a possible contributory pathway from smoking to cardiovascular disease risk but from any feature potentially influencing F2RL3 regulation in a similar manner.
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Affiliation(s)
- Laura J. Corbin
- MRC Integrative Epidemiology Unit at University of Bristol, United Kingdom (L.J.C., L.F., A.G., L.P., M.R.M., C.R., J.L.M., G.D.S., N.J.T.)
- Population Health Sciences, Bristol Medical School (L.J.C., A.E.T., K.T., L.F., A.G., L.P., C.R., J.L.M., G.D.S., N.J.T.), University of Bristol, United Kingdom
| | - Stephen J. White
- Department of Life Sciences, Manchester Metropolitan University, United Kingdom (S.J.W.)
| | - Amy E. Taylor
- Population Health Sciences, Bristol Medical School (L.J.C., A.E.T., K.T., L.F., A.G., L.P., C.R., J.L.M., G.D.S., N.J.T.), University of Bristol, United Kingdom
- NIHR Biomedical Research Centre at the University Hospitals Bristol NHS Foundation Trust and the University of Bristol, United Kingdom (A.E.T.)
| | - Christopher M. Williams
- Population Health Sciences, Bristol Medical School (L.J.C., A.E.T., K.T., L.F., A.G., L.P., C.R., J.L.M., G.D.S., N.J.T.), University of Bristol, United Kingdom
- School of Physiology, Pharmacology and Neuroscience (C.M.W., M.T.v.d.B., A.W.P.), University of Bristol, United Kingdom
| | - Kurt Taylor
- MRC Integrative Epidemiology Unit at University of Bristol, United Kingdom (L.J.C., L.F., A.G., L.P., M.R.M., C.R., J.L.M., G.D.S., N.J.T.)
- Population Health Sciences, Bristol Medical School (L.J.C., A.E.T., K.T., L.F., A.G., L.P., C.R., J.L.M., G.D.S., N.J.T.), University of Bristol, United Kingdom
- School of Physiology, Pharmacology and Neuroscience (C.M.W., M.T.v.d.B., A.W.P.), University of Bristol, United Kingdom
- Translational Health Sciences, Bristol Medical School (J.E.T., M.J., M.B.), University of Bristol, United Kingdom
- UK Centre for Tobacco and Alcohol Studies and School of Experimental Psychology (M.R.M.), University of Bristol, United Kingdom
- School of Cellular and Molecular Medicine (A.D.M.), University of Bristol, United Kingdom
- Department of Life Sciences, Manchester Metropolitan University, United Kingdom (S.J.W.)
- NIHR Biomedical Research Centre at the University Hospitals Bristol NHS Foundation Trust and the University of Bristol, United Kingdom (A.E.T.)
- Department of Pharmacology, University of Cambridge, Tennis Court Road (M.T.H., G.G.J.H.)
- Department of Clinical Biochemistry, Herlev and Gentofte Hospital (B.G.N., S.E.B.), Copenhagen University Hospital, Denmark
- The Copenhagen City Heart Study, Frederiksberg Hospital (B.G.N., A.T.-H., S.E.B.), Copenhagen University Hospital, Denmark
- Department of Clinical Biochemistry, Rigshospitalet (A.T.-H.), Copenhagen University Hospital, Denmark
- Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (B.G.N., A.T.-H., S.E.B.)
| | - Marion T. van den Bosch
- School of Physiology, Pharmacology and Neuroscience (C.M.W., M.T.v.d.B., A.W.P.), University of Bristol, United Kingdom
| | - Jack E. Teasdale
- Translational Health Sciences, Bristol Medical School (J.E.T., M.J., M.B.), University of Bristol, United Kingdom
| | - Matthew Jones
- Translational Health Sciences, Bristol Medical School (J.E.T., M.J., M.B.), University of Bristol, United Kingdom
| | - Mark Bond
- Translational Health Sciences, Bristol Medical School (J.E.T., M.J., M.B.), University of Bristol, United Kingdom
| | - Matthew T. Harper
- Department of Pharmacology, University of Cambridge, Tennis Court Road (M.T.H., G.G.J.H.)
| | - Louise Falk
- MRC Integrative Epidemiology Unit at University of Bristol, United Kingdom (L.J.C., L.F., A.G., L.P., M.R.M., C.R., J.L.M., G.D.S., N.J.T.)
- Population Health Sciences, Bristol Medical School (L.J.C., A.E.T., K.T., L.F., A.G., L.P., C.R., J.L.M., G.D.S., N.J.T.), University of Bristol, United Kingdom
| | - Alix Groom
- MRC Integrative Epidemiology Unit at University of Bristol, United Kingdom (L.J.C., L.F., A.G., L.P., M.R.M., C.R., J.L.M., G.D.S., N.J.T.)
- Population Health Sciences, Bristol Medical School (L.J.C., A.E.T., K.T., L.F., A.G., L.P., C.R., J.L.M., G.D.S., N.J.T.), University of Bristol, United Kingdom
| | - Georgina G.J. Hazell
- Department of Pharmacology, University of Cambridge, Tennis Court Road (M.T.H., G.G.J.H.)
| | - Lavinia Paternoster
- MRC Integrative Epidemiology Unit at University of Bristol, United Kingdom (L.J.C., L.F., A.G., L.P., M.R.M., C.R., J.L.M., G.D.S., N.J.T.)
- Population Health Sciences, Bristol Medical School (L.J.C., A.E.T., K.T., L.F., A.G., L.P., C.R., J.L.M., G.D.S., N.J.T.), University of Bristol, United Kingdom
| | - Marcus R. Munafò
- MRC Integrative Epidemiology Unit at University of Bristol, United Kingdom (L.J.C., L.F., A.G., L.P., M.R.M., C.R., J.L.M., G.D.S., N.J.T.)
- UK Centre for Tobacco and Alcohol Studies and School of Experimental Psychology (M.R.M.), University of Bristol, United Kingdom
| | - Børge G. Nordestgaard
- Department of Clinical Biochemistry, Herlev and Gentofte Hospital (B.G.N., S.E.B.), Copenhagen University Hospital, Denmark
- The Copenhagen City Heart Study, Frederiksberg Hospital (B.G.N., A.T.-H., S.E.B.), Copenhagen University Hospital, Denmark
- Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (B.G.N., A.T.-H., S.E.B.)
| | - Anne Tybjærg-Hansen
- The Copenhagen City Heart Study, Frederiksberg Hospital (B.G.N., A.T.-H., S.E.B.), Copenhagen University Hospital, Denmark
- Department of Clinical Biochemistry, Rigshospitalet (A.T.-H.), Copenhagen University Hospital, Denmark
- Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (B.G.N., A.T.-H., S.E.B.)
| | - Stig E. Bojesen
- Department of Clinical Biochemistry, Herlev and Gentofte Hospital (B.G.N., S.E.B.), Copenhagen University Hospital, Denmark
- The Copenhagen City Heart Study, Frederiksberg Hospital (B.G.N., A.T.-H., S.E.B.), Copenhagen University Hospital, Denmark
- Faculty of Health and Medical Sciences, University of Copenhagen, Denmark (B.G.N., A.T.-H., S.E.B.)
| | - Caroline Relton
- MRC Integrative Epidemiology Unit at University of Bristol, United Kingdom (L.J.C., L.F., A.G., L.P., M.R.M., C.R., J.L.M., G.D.S., N.J.T.)
- Population Health Sciences, Bristol Medical School (L.J.C., A.E.T., K.T., L.F., A.G., L.P., C.R., J.L.M., G.D.S., N.J.T.), University of Bristol, United Kingdom
| | - Josine L. Min
- MRC Integrative Epidemiology Unit at University of Bristol, United Kingdom (L.J.C., L.F., A.G., L.P., M.R.M., C.R., J.L.M., G.D.S., N.J.T.)
- Population Health Sciences, Bristol Medical School (L.J.C., A.E.T., K.T., L.F., A.G., L.P., C.R., J.L.M., G.D.S., N.J.T.), University of Bristol, United Kingdom
| | - George Davey Smith
- MRC Integrative Epidemiology Unit at University of Bristol, United Kingdom (L.J.C., L.F., A.G., L.P., M.R.M., C.R., J.L.M., G.D.S., N.J.T.)
- Population Health Sciences, Bristol Medical School (L.J.C., A.E.T., K.T., L.F., A.G., L.P., C.R., J.L.M., G.D.S., N.J.T.), University of Bristol, United Kingdom
| | - Andrew D. Mumford
- School of Cellular and Molecular Medicine (A.D.M.), University of Bristol, United Kingdom
| | - Alastair W. Poole
- School of Physiology, Pharmacology and Neuroscience (C.M.W., M.T.v.d.B., A.W.P.), University of Bristol, United Kingdom
| | - Nicholas J. Timpson
- MRC Integrative Epidemiology Unit at University of Bristol, United Kingdom (L.J.C., L.F., A.G., L.P., M.R.M., C.R., J.L.M., G.D.S., N.J.T.)
- Population Health Sciences, Bristol Medical School (L.J.C., A.E.T., K.T., L.F., A.G., L.P., C.R., J.L.M., G.D.S., N.J.T.), University of Bristol, United Kingdom
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9
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Abstract
Structurally, aquaporins (AQPs) are small channel proteins with monomers of ~ 30 kDa that are assembled as tetramers to form pores on cell membranes. Aquaporins mediate the conduction of water but at times also small solutes including glycerol across cell membranes and along osmotic gradients. Thirteen isoforms of AQPs have been reported in mammalian cells, and several of these are likely expressed in platelets. Osmotic swelling mediated by AQP1 sustains the calcium entry required for platelet phosphatidylserine exposure and microvesiculation, through calcium permeable stretch-activated or mechanosensitive cation channels. Notably, deletion of AQP1 diminishes platelet procoagulant membrane dynamics in vitro and arterial thrombosis in vivo, independent of platelet granule secretion and without affecting hemostasis. Water entry into platelets promotes procoagulant activity, and AQPs may also be critical for the initiation and progression of venous thrombosis. Platelet AQPs may therefore represent valuable targets for future development of a new class of antithrombotics, namely, anti-procoagulant antithrombotics, that are mechanistically distinct from current antithrombotics. However, the structure of AQPs does not make for easy targeting of these channels, hence they remain elusive drug targets. Nevertheless, thrombosis data in animal models provide compelling reasons to continue the pursuit of AQP-targeted antithrombotics. In this review, we discuss the role of aquaporins in platelet secretion, aggregation and procoagulation, the challenge of drugging AQPs, and the prospects of targeting AQPs for arterial and venous antithrombosis.
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Affiliation(s)
- Ejaife O Agbani
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Alberta, Canada
| | - Alastair W Poole
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, England, UK
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10
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Moore SF, Agbani EO, Wersäll A, Poole AW, Williams CM, Zhao X, Li Y, Hutchinson JL, Hunter RW, Hers I. Opposing Roles of GSK3α and GSK3β Phosphorylation in Platelet Function and Thrombosis. Int J Mol Sci 2021; 22:10656. [PMID: 34638997 PMCID: PMC8508950 DOI: 10.3390/ijms221910656] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 09/16/2021] [Accepted: 09/22/2021] [Indexed: 11/25/2022] Open
Abstract
One of the mechanisms by which PI3 kinase can regulate platelet function is through phosphorylation of downstream substrates, including glycogen synthase kinase-3 (GSK3)α and GSK3β. Platelet activation results in the phosphorylation of an N-terminal serine residue in GSK3α (Ser21) and GSK3β (Ser9), which competitively inhibits substrate phosphorylation. However, the role of phosphorylation of these paralogs is still largely unknown. Here, we employed GSK3α/β phosphorylation-resistant mouse models to explore the role of this inhibitory phosphorylation in regulating platelet activation. Expression of phosphorylation-resistant GSK3α/β reduced thrombin-mediated platelet aggregation, integrin αIIbβ3 activation, and α-granule secretion, whereas platelet responses to the GPVI agonist collagen-related peptide (CRP-XL) were significantly enhanced. GSK3 single knock-in lines revealed that this divergence is due to differential roles of GSK3α and GSK3β phosphorylation in regulating platelet function. Expression of phosphorylation-resistant GSK3α resulted in enhanced GPVI-mediated platelet activation, whereas expression of phosphorylation-resistant GSK3β resulted in a reduction in PAR-mediated platelet activation and impaired in vitro thrombus formation under flow. Interestingly, the latter was normalised in double GSK3α/β KI mice, indicating that GSK3α KI can compensate for the impairment in thrombosis caused by GSK3β KI. In conclusion, our data indicate that GSK3α and GSK3β have differential roles in regulating platelet function.
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Affiliation(s)
- Samantha F. Moore
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK; (S.F.M.); (E.O.A.); (A.W.); (A.W.P.); (C.M.W.); (X.Z.); (Y.L.); (J.L.H.); (R.W.H.)
| | - Ejaife O. Agbani
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK; (S.F.M.); (E.O.A.); (A.W.); (A.W.P.); (C.M.W.); (X.Z.); (Y.L.); (J.L.H.); (R.W.H.)
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Andreas Wersäll
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK; (S.F.M.); (E.O.A.); (A.W.); (A.W.P.); (C.M.W.); (X.Z.); (Y.L.); (J.L.H.); (R.W.H.)
| | - Alastair W. Poole
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK; (S.F.M.); (E.O.A.); (A.W.); (A.W.P.); (C.M.W.); (X.Z.); (Y.L.); (J.L.H.); (R.W.H.)
| | - Chris M. Williams
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK; (S.F.M.); (E.O.A.); (A.W.); (A.W.P.); (C.M.W.); (X.Z.); (Y.L.); (J.L.H.); (R.W.H.)
| | - Xiaojuan Zhao
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK; (S.F.M.); (E.O.A.); (A.W.); (A.W.P.); (C.M.W.); (X.Z.); (Y.L.); (J.L.H.); (R.W.H.)
| | - Yong Li
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK; (S.F.M.); (E.O.A.); (A.W.); (A.W.P.); (C.M.W.); (X.Z.); (Y.L.); (J.L.H.); (R.W.H.)
| | - James L. Hutchinson
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK; (S.F.M.); (E.O.A.); (A.W.); (A.W.P.); (C.M.W.); (X.Z.); (Y.L.); (J.L.H.); (R.W.H.)
| | - Roger W. Hunter
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK; (S.F.M.); (E.O.A.); (A.W.); (A.W.P.); (C.M.W.); (X.Z.); (Y.L.); (J.L.H.); (R.W.H.)
- NHS Blood and Transplant, North Bristol Park, Filton, Bristol BS34 7QH, UK
| | - Ingeborg Hers
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK; (S.F.M.); (E.O.A.); (A.W.); (A.W.P.); (C.M.W.); (X.Z.); (Y.L.); (J.L.H.); (R.W.H.)
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11
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Zhao X, Alibhai D, Sun T, Khalil J, Hutchinson JL, Olzak K, Williams CM, Li Y, Sessions R, Cross S, Seager R, Aungraheeta R, Leard A, McKinnon CM, Phillips D, Zhang L, Poole AW, Banting G, Mundell SJ. Tetherin/BST2, a physiologically and therapeutically relevant regulator of platelet receptor signalling. Blood Adv 2021; 5:1884-1898. [PMID: 33792632 PMCID: PMC8045503 DOI: 10.1182/bloodadvances.2020003182] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 01/20/2021] [Indexed: 11/20/2022] Open
Abstract
The reactivity of platelets, which play a key role in the pathogenesis of atherothrombosis, is tightly regulated. The integral membrane protein tetherin/bone marrow stromal antigen-2 (BST-2) regulates membrane organization, altering both lipid and protein distribution within the plasma membrane. Because membrane microdomains have an established role in platelet receptor biology, we sought to characterize the physiological relevance of tetherin/BST-2 in those cells. To characterize the potential importance of tetherin/BST-2 to platelet function, we used tetherin/BST-2-/- murine platelets. In the mice, we found enhanced function and signaling downstream of a subset of membrane microdomain-expressing receptors, including the P2Y12, TP thromboxane, thrombin, and GPVI receptors. Preliminary studies in humans have revealed that treatment with interferon-α (IFN-α), which upregulates platelet tetherin/BST-2 expression, also reduces adenosine diphosphate-stimulated platelet receptor function and reactivity. A more comprehensive understanding of how tetherin/BST-2 negatively regulates receptor function was provided in cell line experiments, where we focused on the therapeutically relevant P2Y12 receptor (P2Y12R). Tetherin/BST-2 expression reduced both P2Y12R activation and trafficking, which was accompanied by reduced receptor lateral mobility specifically within membrane microdomains. In fluorescence lifetime imaging-Förster resonance energy transfer (FLIM-FRET)-based experiments, agonist stimulation reduced basal association between P2Y12R and tetherin/BST-2. Notably, the glycosylphosphatidylinositol (GPI) anchor of tetherin/BST-2 was required for both receptor interaction and observed functional effects. In summary, we established, for the first time, a fundamental role of the ubiquitously expressed protein tetherin/BST-2 in negatively regulating membrane microdomain-expressed platelet receptor function.
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Affiliation(s)
- Xiaojuan Zhao
- School of Physiology, Pharmacology, and Neuroscience, and
| | - Dominic Alibhai
- Wolfson Bioimaging Facility, University of Bristol, Bristol, United Kingdom
| | - Ting Sun
- State Key Laboratory of Experimental Hematology, Key Laboratory of Gene Therapy for Blood Disease, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin, China; and
| | - Jawad Khalil
- School of Physiology, Pharmacology, and Neuroscience, and
| | | | - Kaya Olzak
- School of Physiology, Pharmacology, and Neuroscience, and
| | | | - Yong Li
- School of Physiology, Pharmacology, and Neuroscience, and
| | - Richard Sessions
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | - Stephen Cross
- Wolfson Bioimaging Facility, University of Bristol, Bristol, United Kingdom
| | - Richard Seager
- School of Physiology, Pharmacology, and Neuroscience, and
| | | | - Alan Leard
- Wolfson Bioimaging Facility, University of Bristol, Bristol, United Kingdom
| | | | - David Phillips
- School of Physiology, Pharmacology, and Neuroscience, and
| | - Lei Zhang
- State Key Laboratory of Experimental Hematology, Key Laboratory of Gene Therapy for Blood Disease, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin, China; and
| | | | - George Banting
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
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12
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Aburima A, Berger M, Spurgeon BEJ, Webb BA, Wraith KS, Febbraio M, Poole AW, Naseem KM. Thrombospondin-1 promotes hemostasis through modulation of cAMP signaling in blood platelets. Blood 2021; 137:678-689. [PMID: 33538796 DOI: 10.1182/blood.2020005382] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 07/31/2020] [Indexed: 01/16/2023] Open
Abstract
Thrombospondin-1 (TSP-1) is released by platelets upon activation and can increase platelet activation, but its role in hemostasis in vivo is unclear. We show that TSP-1 is a critical mediator of hemostasis that promotes platelet activation by modulating inhibitory cyclic adenosine monophosphate (cAMP) signaling. Genetic deletion of TSP-1 did not affect platelet activation in vitro, but in vivo models of hemostasis and thrombosis showed that TSP-1-deficient mice had prolonged bleeding, defective thrombosis, and increased sensitivity to the prostacyclin mimetic iloprost. Adoptive transfer of wild-type (WT) but not TSP-1-/- platelets ameliorated the thrombotic phenotype, suggesting a key role for platelet-derived TSP-1. In functional assays, TSP-1-deficient platelets showed an increased sensitivity to cAMP signaling, inhibition of platelet aggregation, and arrest under flow by prostacyclin (PGI2). Plasma swap experiments showed that plasma TSP-1 did not correct PGI2 hypersensitivity in TSP-1-/- platelets. By contrast, incubation of TSP-1-/- platelets with releasates from WT platelets or purified TSP-1, but not releasates from TSP-1-/- platelets, reduced the inhibitory effects of PGI2. Activation of WT platelets resulted in diminished cAMP accumulation and downstream signaling, which was associated with increased activity of the cAMP hydrolyzing enzyme phosphodiesterase 3A (PDE3A). PDE3A activity and cAMP accumulation were unaffected in platelets from TSP-1-/- mice. Platelets deficient in CD36, a TSP-1 receptor, showed increased sensitivity to PGI2/cAMP signaling and diminished PDE3A activity, which was unaffected by platelet-derived or purified TSP-1. This scenario suggests that the release of TSP-1 regulates hemostasis in vivo through modulation of platelet cAMP signaling at sites of vascular injury.
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Affiliation(s)
- Ahmed Aburima
- Centre for Atherothrombosis and Metabolic Disease, Hull York Medical School, University of Hull, Hull, United Kingdom
| | - Martin Berger
- Faculty of Medicine, RWTH Aachen University, Aachen, Germany
- Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom
| | - Benjamin E J Spurgeon
- Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom
| | - Bethany A Webb
- Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom
| | - Katie S Wraith
- Centre for Atherothrombosis and Metabolic Disease, Hull York Medical School, University of Hull, Hull, United Kingdom
| | - Maria Febbraio
- School of Dentistry, University of Alberta, Edmonton, AB, Canada; and
| | - Alastair W Poole
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Khalid M Naseem
- Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom
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13
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Agbani EO, Zhao X, Williams CM, Aungraheeta R, Hers I, Swenson ER, Poole AW. Carbonic Anhydrase Inhibitors suppress platelet procoagulant responses and in vivo thrombosis. Platelets 2020; 31:853-859. [PMID: 31893963 DOI: 10.1080/09537104.2019.1709632] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Carbonic anhydrase (CA) inhibitors have a long history of safe clinical use as mild diuretics, in the treatment of glaucoma and for altitude sickness prevention. In this study, we aimed to determine if CA inhibition may be an alternative approach to control thrombosis. We utilized a high-resolution dynamic imaging approach to provide mechanistic evidence that CA inhibitors may be potent anti-procoagulant agents in vitro and effective anti-thrombotics in vivo. Acetazolamide and methazolamide, while sparing platelet secretion, attenuated intracellular chloride ion entry and suppressed the procoagulant response of activated platelets in vitro and thrombosis in vivo. The chemically similar N-methyl acetazolamide, which lacks CA inhibitory activity, did not affect platelet procoagulant response in vitro. Outputs from rotational thromboelastometry did not reflect changes in procoagulant activity and reveal the need for a suitable clinical test for procoagulant activity. Drugs specifically targeting procoagulant remodeling of activated platelets, by blockade of carbonic anhydrases, may provide a new way to control platelet-driven thrombosis without blocking essential platelet secretion responses.
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Affiliation(s)
- Ejaife O Agbani
- School of Physiology, Pharmacology and Neuroscience, University of Bristol , Bristol, UK.,Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary , Calgary, Alberta, Canada.,Vascular Basic Science, Libin Cardiovascular Institute of Alberta , Calgary, Alberta, Canada
| | - Xiaojuan Zhao
- School of Physiology, Pharmacology and Neuroscience, University of Bristol , Bristol, UK
| | - Christopher M Williams
- School of Physiology, Pharmacology and Neuroscience, University of Bristol , Bristol, UK
| | - Riyaad Aungraheeta
- School of Physiology, Pharmacology and Neuroscience, University of Bristol , Bristol, UK
| | - Ingeborg Hers
- School of Physiology, Pharmacology and Neuroscience, University of Bristol , Bristol, UK
| | - Erik R Swenson
- Division of Pulmonary, Critical Care and Sleep Medicine, Medical Service, VA Puget Sound Health Care System, University of Washington , Seattle, WA, USA
| | - Alastair W Poole
- School of Physiology, Pharmacology and Neuroscience, University of Bristol , Bristol, UK
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14
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Agbani EO, Hers I, Poole AW. Letter by Agbani et al Regarding Article, "Clot Contraction Drives the Translocation of Procoagulant Platelets to Thrombus Surface". Arterioscler Thromb Vasc Biol 2019; 39:e287-e289. [PMID: 31770030 DOI: 10.1161/atvbaha.119.313468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Ejaife O Agbani
- From the Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Alberta, Canada (E.O.A.)
| | - Ingeborg Hers
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, England, United Kingdom (I.H., A.W.P.)
| | - Alastair W Poole
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, England, United Kingdom (I.H., A.W.P.)
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15
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Nagy M, van Geffen JP, Stegner D, Adams DJ, Braun A, de Witt SM, Elvers M, Geer MJ, Kuijpers MJE, Kunzelmann K, Mori J, Oury C, Pircher J, Pleines I, Poole AW, Senis YA, Verdoold R, Weber C, Nieswandt B, Heemskerk JWM, Baaten CCFMJ. Comparative Analysis of Microfluidics Thrombus Formation in Multiple Genetically Modified Mice: Link to Thrombosis and Hemostasis. Front Cardiovasc Med 2019; 6:99. [PMID: 31417909 PMCID: PMC6682619 DOI: 10.3389/fcvm.2019.00099] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 07/03/2019] [Indexed: 12/15/2022] Open
Abstract
Genetically modified mice are indispensable for establishing the roles of platelets in arterial thrombosis and hemostasis. Microfluidics assays using anticoagulated whole blood are commonly used as integrative proxy tests for platelet function in mice. In the present study, we quantified the changes in collagen-dependent thrombus formation for 38 different strains of (genetically) modified mice, all measured with the same microfluidics chamber. The mice included were deficient in platelet receptors, protein kinases or phosphatases, small GTPases or other signaling or scaffold proteins. By standardized re-analysis of high-resolution microscopic images, detailed information was obtained on altered platelet adhesion, aggregation and/or activation. For a subset of 11 mouse strains, these platelet functions were further evaluated in rhodocytin- and laminin-dependent thrombus formation, thus allowing a comparison of glycoprotein VI (GPVI), C-type lectin-like receptor 2 (CLEC2) and integrin α6β1 pathways. High homogeneity was found between wild-type mice datasets concerning adhesion and aggregation parameters. Quantitative comparison for the 38 modified mouse strains resulted in a matrix visualizing the impact of the respective (genetic) deficiency on thrombus formation with detailed insight into the type and extent of altered thrombus signatures. Network analysis revealed strong clusters of genes involved in GPVI signaling and Ca2+ homeostasis. The majority of mice demonstrating an antithrombotic phenotype in vivo displayed with a larger or smaller reduction in multi-parameter analysis of collagen-dependent thrombus formation in vitro. Remarkably, in only approximately half of the mouse strains that displayed reduced arterial thrombosis in vivo, this was accompanied by impaired hemostasis. This was also reflected by comparing in vitro thrombus formation (by microfluidics) with alterations in in vivo bleeding time. In conclusion, the presently developed multi-parameter analysis of thrombus formation using microfluidics can be used to: (i) determine the severity of platelet abnormalities; (ii) distinguish between altered platelet adhesion, aggregation and activation; and (iii) elucidate both collagen and non-collagen dependent alterations of thrombus formation. This approach may thereby aid in the better understanding and better assessment of genetic variation that affect in vivo arterial thrombosis and hemostasis.
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Affiliation(s)
- Magdolna Nagy
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, Netherlands
| | - Johanna P van Geffen
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, Netherlands
| | - David Stegner
- Rudolf Virchow Center, Institute of Experimental Biomedicine, University Hospital Würzburg, University of Würzburg, Würzburg, Germany
| | - David J Adams
- Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Attila Braun
- Rudolf Virchow Center, Institute of Experimental Biomedicine, University Hospital Würzburg, University of Würzburg, Würzburg, Germany
| | - Susanne M de Witt
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, Netherlands
| | - Margitta Elvers
- Department of Vascular Surgery, Experimental Vascular Medicine, Heinrich Heine University, Düsseldorf, Germany
| | - Mitchell J Geer
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Marijke J E Kuijpers
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, Netherlands
| | - Karl Kunzelmann
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Jun Mori
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Cécile Oury
- GIGA-Cardiovascular Sciences, University of Liège, Liège, Belgium
| | - Joachim Pircher
- Medizinische Klinik und Poliklinik I, Klinikum der Universität München, Ludwig-Maximilians-University, and DZHK (German Center for Cardiovascular Research), Partner Site Munich Heart Alliance, Munich, Germany
| | - Irina Pleines
- Rudolf Virchow Center, Institute of Experimental Biomedicine, University Hospital Würzburg, University of Würzburg, Würzburg, Germany
| | - Alastair W Poole
- Department of Physiology and Pharmacology, School of Medical Sciences, University of Bristol, Bristol, United Kingdom
| | - Yotis A Senis
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Remco Verdoold
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, Netherlands
| | - Christian Weber
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, Netherlands.,Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-Universität München, Munich, Germany
| | - Bernhard Nieswandt
- Rudolf Virchow Center, Institute of Experimental Biomedicine, University Hospital Würzburg, University of Würzburg, Würzburg, Germany
| | - Johan W M Heemskerk
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, Netherlands
| | - Constance C F M J Baaten
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, Netherlands.,Institute for Molecular Cardiovascular Research (IMCAR), University Hospital Aachen, Aachen, Germany
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16
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Walsh TG, Wersäll A, Poole AW. Characterisation of the Ral GTPase inhibitor RBC8 in human and mouse platelets. Cell Signal 2019; 59:34-40. [PMID: 30880223 PMCID: PMC6510928 DOI: 10.1016/j.cellsig.2019.03.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 03/13/2019] [Accepted: 03/13/2019] [Indexed: 01/28/2023]
Abstract
The Ral GTPases, RalA and RalB, have been implicated in numerous cellular processes, but are most widely known for having regulatory roles in exocytosis. Recently, we demonstrated that deletion of both Ral genes in a platelet-specific mouse gene knockout caused a substantial defect in surface exposure of P-selectin, with only a relatively weak defect in platelet dense granule secretion that did not alter platelet functional responses such as aggregation or thrombus formation. We sought to investigate the function of Rals in human platelets using the recently described Ral inhibitor, RBC8. Initial studies in human platelets confirmed that RBC8 could effectively inhibit Ral GTPase activation, with an IC50 of 2.2 μM and 2.3 μM for RalA and RalB, respectively. Functional studies using RBC8 revealed significant, dose-dependent inhibition of platelet aggregation, secretion (α- and dense granule), integrin activation and thrombus formation, while α-granule release of platelet factor 4, Ca2+ signalling or phosphatidylserine exposure were unaltered. Subsequent studies in RalAB-null mouse platelets pretreated with RBC8 showed dose-dependent decreases in integrin activation and dense granule secretion, with significant inhibition of platelet aggregation and P-selectin exposure at 10 μM RBC8. This study strongly suggests therefore that although RBC8 is useful as a Ral inhibitor in platelets, it is likely also to have off-target effects in the same concentration range as for Ral inhibition. So, whilst clearly useful as a Ral inhibitor, interpretation of data needs to take this into account when assessing roles for Rals using RBC8.
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Affiliation(s)
- Tony G Walsh
- From the School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol BS8 1TD, United Kingdom.
| | - Andreas Wersäll
- From the School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Alastair W Poole
- From the School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol BS8 1TD, United Kingdom
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17
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Abstract
Our understanding of fundamental biological processes within platelets is continually evolving. A critical feature of platelet biology relates to the intricate uptake, packaging and release of bioactive cargo from storage vesicles, essential in mediating a range of classical (haemostasis/thrombosis) and non-classical (regeneration/inflammation/metastasis) roles platelets assume. Pivotal to the molecular control of these vesicle trafficking events are the small GTPases of the Ras superfamily, which function as spatially distinct, molecular switches controlling essential cellular processes. Herein, we specifically focus on members of the Rab, Arf and Ras subfamilies, which comprise over 130 members and platelet proteomic datasets suggest that more than half of these are expressed in human platelets. We provide an update of current literature relating to trafficking roles for these GTPases in platelets, particularly regarding endocytic and exocytic events, but also vesicle biogenesis and provide speculative argument for roles that other related GTPases and regulatory proteins may adopt in platelets. Advances in our understanding of small GTPase function in the anucleate platelet has been hampered by the lack of specific molecular tools, but it is anticipated that this will be greatly accelerated in the years ahead and will be crucial to the identification of novel therapeutic targets controlling different platelet processes.
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Affiliation(s)
- Tony G Walsh
- a From the School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building , University of Bristol , Bristol , UK
| | - Yong Li
- a From the School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building , University of Bristol , Bristol , UK
| | - Andreas Wersäll
- a From the School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building , University of Bristol , Bristol , UK
| | - Alastair W Poole
- a From the School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building , University of Bristol , Bristol , UK
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18
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Blair TA, Moore SF, Walsh TG, Hutchinson JL, Durrant TN, Anderson KE, Poole AW, Hers I. Phosphoinositide 3-kinase p110α negatively regulates thrombopoietin-mediated platelet activation and thrombus formation. Cell Signal 2018; 50:111-120. [PMID: 29793021 DOI: 10.1016/j.cellsig.2018.05.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 05/17/2018] [Accepted: 05/18/2018] [Indexed: 01/21/2023]
Abstract
Phosphoinositide 3-kinase (PI3K) plays an important role in platelet function and contributes to platelet hyperreactivity induced by elevated levels of circulating peptide hormones, including thrombopoietin (TPO). Previous work established an important role for the PI3K isoform; p110β in platelet function, however the role of p110α is still largely unexplored. Here we sought to investigate the role of p110α in TPO-mediated hyperactivity by using a conditional p110α knockout (KO) murine model in conjunction with platelet functional assays. We found that TPO-mediated enhancement of collagen-related peptide (CRP-XL)-induced platelet aggregation and adenosine triphosphate (ATP) secretion were significantly increased in p110α KO platelets. Furthermore, TPO-mediated enhancement of thrombus formation by p110α KO platelets was elevated over wild-type (WT) platelets, suggesting that p110α negatively regulates TPO-mediated priming of platelet function. The enhancements were not due to increased flow through the PI3K pathway as phosphatidylinositol 3,4,5-trisphosphate (PI(3,4,5)P3) formation and phosphorylation of Akt and glycogen synthase kinase 3 (GSK3) were comparable between WT and p110α KO platelets. In contrast, extracellular responsive kinase (ERK) phosphorylation and thromboxane (TxA2) formation were significantly enhanced in p110α KO platelets, both of which were blocked by the MEK inhibitor PD184352, whereas the p38 MAPK inhibitor VX-702 and p110α inhibitor PIK-75 had no effect. Acetylsalicylic acid (ASA) blocked the enhancement of thrombus formation by TPO in both WT and p110α KO mice. Together, these results demonstrate that p110α negatively regulates TPO-mediated enhancement of platelet function by restricting ERK phosphorylation and TxA2 synthesis in a manner independent of its kinase activity.
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Affiliation(s)
- T A Blair
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, United Kingdom
| | - S F Moore
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, United Kingdom
| | - T G Walsh
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, United Kingdom
| | - J L Hutchinson
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, United Kingdom
| | - T N Durrant
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, United Kingdom
| | - K E Anderson
- Inositide Laboratory, Babraham Institute, Cambridge, United Kingdom
| | - A W Poole
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, United Kingdom
| | - I Hers
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, United Kingdom.
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19
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Abstract
Platelets, cells central to hemostasis and thrombosis, are formed from parent cell megakaryocytes. Whilst the process is highly efficient in vivo, our ability to generate them in vitro is still remarkably inefficient. We proposed that greater understanding of the process in vivo is needed and used an imaging approach, intravital correlative light-electron microscopy, to visualize platelet generation in bone marrow in the living mouse. In contrast to current understanding we found that most megakaryocytes enter the sinusoidal space as large protrusions rather than extruding fine proplatelet extensions. The mechanism for large protrusion migration also differed from that of proplatelet extension. In vitro, proplatelets extend by sliding of dense bundles of microtubules, whereas in vivo our data showed an absence of microtubule bundles in the large protrusion, but the presence of multiple fusion points between the internal membrane and the plasma membrane, at the leading edge of the protruding cell. Mass membrane fusion therefore drives megakaryocyte large protrusions into the sinusoid, significantly revising our understanding of the fundamental biology of platelet formation in vivo.
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Affiliation(s)
- Edward Brown
- School of Physiology and Pharmacology, Faculty of Medical and Veterinary Sciences, University of Bristol, Bristol, BS8 1TD, UK
| | - Leo M Carlin
- Cancer Research UK Beatson Institute, Garscube Campus, Switchback Road, Bearsden, Glasgow G61 1BD, UK.,Inflammation, Repair & Development, National Heart & Lung Institute, London, SW7 2AZ, UK
| | - Claus Nerlov
- MRC Molecular Hematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DS, UK
| | - Cristina Lo Celso
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London, SW7 2AZ, UK.,The Francis Crick Institute, 1 Midland Road, London NW1A 1AT, UK
| | - Alastair W Poole
- School of Physiology and Pharmacology, Faculty of Medical and Veterinary Sciences, University of Bristol, Bristol, BS8 1TD, UK
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20
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Agbani EO, Williams CM, Li Y, van den Bosch MT, Moore SF, Mauroux A, Hodgson L, Verkman AS, Hers I, Poole AW. Aquaporin-1 regulates platelet procoagulant membrane dynamics and in vivo thrombosis. JCI Insight 2018; 3:99062. [PMID: 29769447 PMCID: PMC6012506 DOI: 10.1172/jci.insight.99062] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 04/12/2018] [Indexed: 01/02/2023] Open
Abstract
In response to collagen stimulation, platelets use a coordinated system of fluid entry to undergo membrane ballooning, procoagulant spreading, and microvesiculation. We hypothesized that water entry was mediated by the water channel aquaporin-1 (AQP1) and aimed to determine its role in the platelet procoagulant response and thrombosis. We established that human and mouse platelets express AQP1 and localize to internal tubular membrane structures. However, deletion of AQP1 had minimal effects on collagen-induced platelet granule secretion, aggregation, or membrane ballooning. Conversely, procoagulant spreading, microvesiculation, phosphatidylserine exposure, and clot formation time were significantly diminished. Furthermore, in vivo thrombus formation after FeCl3 injury to carotid arteries was also markedly suppressed in AQP1-null mice, but hemostasis after tail bleeding remained normal. The mechanism involves an AQP1-mediated rapid membrane stretching during procoagulant spreading but not ballooning, leading to calcium entry through mechanosensitive cation channels and a full procoagulant response. We conclude that AQP1 is a major regulator of the platelet procoagulant response, able to modulate coagulation after injury or pathologic stimuli without affecting other platelet functional responses or normal hemostasis. Clinically effective AQP1 inhibitors may therefore represent a novel class of antiprocoagulant antithrombotics. AQP1 controls platelet procoagulant response and modulates coagulation after injury or pathologic stimuli without affecting other platelet functional responses or normal hemostasis.
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Affiliation(s)
- Ejaife O Agbani
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, Bristol, United Kingdom.,Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Christopher M Williams
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, Bristol, United Kingdom
| | - Yong Li
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, Bristol, United Kingdom
| | - Marion Tj van den Bosch
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, Bristol, United Kingdom
| | - Samantha F Moore
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, Bristol, United Kingdom
| | - Adele Mauroux
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, Bristol, United Kingdom
| | - Lorna Hodgson
- Wolfson Bioimaging Facility, University of Bristol, Biomedical Sciences Building, Bristol, United Kingdom
| | - Alan S Verkman
- Departments of Medicine and Physiology, University of California San Francisco, San Francisco, California, USA
| | - Ingeborg Hers
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, Bristol, United Kingdom
| | - Alastair W Poole
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, Bristol, United Kingdom
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21
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Wersäll A, Williams CM, Brown E, Iannitti T, Williams N, Poole AW. Mouse Platelet Ral GTPases Control P-Selectin Surface Expression, Regulating Platelet-Leukocyte Interaction. Arterioscler Thromb Vasc Biol 2018; 38:787-800. [PMID: 29437579 DOI: 10.1161/atvbaha.117.310294] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 01/25/2018] [Indexed: 01/28/2023]
Abstract
OBJECTIVE RalA and RalB GTPases are important regulators of cell growth, cancer metastasis, and granule secretion. The purpose of this study was to determine the role of Ral GTPases in platelets with the use of platelet-specific gene-knockout mouse models. APPROACH AND RESULTS This study shows that platelets from double knockout mice, in which both GTPases have been deleted, show markedly diminished (≈85% reduction) P-selectin translocation to the surface membrane, suggesting a critical role in α-granule secretion. Surprisingly, however, there were only minor effects on stimulated release of soluble α- and δ-granule content, with no alteration in granule count, morphology, or content. In addition, their expression was not essential for platelet aggregation or thrombus formation. However, absence of surface P-selectin caused a marked reduction (≈70%) in platelet-leukocyte interactions in blood from RalAB double knockout mice, suggesting a role for platelet Rals in platelet-mediated inflammation. CONCLUSIONS Platelet Ral GTPases primarily control P-selectin surface expression, in turn regulating platelet-leukocyte interaction. Ral GTPases could therefore be important novel targets for the selective control of platelet-mediated immune cell recruitment and inflammatory disease.
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Affiliation(s)
- Andreas Wersäll
- From the School of Physiology, Pharmacology and Neuroscience, University of Bristol, United Kingdom (A.W., C.M.W., E.B., A.W.P.); and KWS Biotest, Portishead, Bristol, United Kingdom (T.I., N.W.).
| | - Chris M Williams
- From the School of Physiology, Pharmacology and Neuroscience, University of Bristol, United Kingdom (A.W., C.M.W., E.B., A.W.P.); and KWS Biotest, Portishead, Bristol, United Kingdom (T.I., N.W.)
| | - Edward Brown
- From the School of Physiology, Pharmacology and Neuroscience, University of Bristol, United Kingdom (A.W., C.M.W., E.B., A.W.P.); and KWS Biotest, Portishead, Bristol, United Kingdom (T.I., N.W.)
| | - Tommaso Iannitti
- From the School of Physiology, Pharmacology and Neuroscience, University of Bristol, United Kingdom (A.W., C.M.W., E.B., A.W.P.); and KWS Biotest, Portishead, Bristol, United Kingdom (T.I., N.W.)
| | - Neil Williams
- From the School of Physiology, Pharmacology and Neuroscience, University of Bristol, United Kingdom (A.W., C.M.W., E.B., A.W.P.); and KWS Biotest, Portishead, Bristol, United Kingdom (T.I., N.W.)
| | - Alastair W Poole
- From the School of Physiology, Pharmacology and Neuroscience, University of Bristol, United Kingdom (A.W., C.M.W., E.B., A.W.P.); and KWS Biotest, Portishead, Bristol, United Kingdom (T.I., N.W.)
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22
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Abstract
Our understanding of platelet function has traditionally focused on their roles in physiological hemostasis and pathological thrombosis, with the latter being causative of vessel occlusion and subsequent ischemic damage to various tissues. In particular, numerous in vivo studies have implicated causative roles for platelets in the pathogenesis of ischemia-reperfusion (I/R) injury to the myocardium. However, platelets clearly have more complex pathophysiological roles, particularly as a result of the heterogeneous nature of biologically active cargo secreted from their granules or contained within released microparticles or exosomes. While some of these released mediators amplify platelet activation and thrombosis through autocrine or paracrine amplification pathways, they can also regulate diverse cellular functions within the localized microenvironment and recruit progenitor cells to the damage site to facilitate repair processes. Notably, there is evidence to support cardioprotective roles for platelet mediators during I/R injury. As such, it is becoming more widely appreciated that platelets fulfill a host of physiological and pathological roles beyond our basic understanding. Therefore, the purpose of this perspective is to consider whether platelets, through their released mediators, can assume a paradoxically beneficial role to promote cardiac recovery after I/R injury.
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Affiliation(s)
- Tony G Walsh
- School of Physiology, Pharmacology and Neuroscience, University of Bristol , Bristol , United Kingdom
| | - Alastair W Poole
- School of Physiology, Pharmacology and Neuroscience, University of Bristol , Bristol , United Kingdom
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23
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Lauder SN, Allen-Redpath K, Slatter DA, Aldrovandi M, O'Connor A, Farewell D, Percy CL, Molhoek JE, Rannikko S, Tyrrell VJ, Ferla S, Milne GL, Poole AW, Thomas CP, Obaji S, Taylor PR, Jones SA, de Groot PG, Urbanus RT, Hörkkö S, Uderhardt S, Ackermann J, Vince Jenkins P, Brancale A, Krönke G, Collins PW, O'Donnell VB. Networks of enzymatically oxidized membrane lipids support calcium-dependent coagulation factor binding to maintain hemostasis. Sci Signal 2017; 10:10/507/eaan2787. [PMID: 29184033 DOI: 10.1126/scisignal.aan2787] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Blood coagulation functions as part of the innate immune system by preventing bacterial invasion, and it is critical to stopping blood loss (hemostasis). Coagulation involves the external membrane surface of activated platelets and leukocytes. Using lipidomic, genetic, biochemical, and mathematical modeling approaches, we found that enzymatically oxidized phospholipids (eoxPLs) generated by the activity of leukocyte or platelet lipoxygenases (LOXs) were required for normal hemostasis and promoted coagulation factor activities in a Ca2+- and phosphatidylserine (PS)-dependent manner. In wild-type mice, hydroxyeicosatetraenoic acid-phospholipids (HETE-PLs) enhanced coagulation and restored normal hemostasis in clotting-deficient animals genetically lacking p12-LOX or 12/15-LOX activity. Murine platelets generated 22 eoxPL species, all of which were missing in the absence of p12-LOX. Humans with the thrombotic disorder antiphospholipid syndrome (APS) had statistically significantly increased HETE-PLs in platelets and leukocytes, as well as greater HETE-PL immunoreactivity, than healthy controls. HETE-PLs enhanced membrane binding of the serum protein β2GP1 (β2-glycoprotein 1), an event considered central to the autoimmune reactivity responsible for APS symptoms. Correlation network analysis of 47 platelet eoxPL species in platelets from APS and control subjects identified their enzymatic origin and revealed a complex network of regulation, with the abundance of 31 p12-LOX-derived eoxPL molecules substantially increased in APS. In summary, circulating blood cells generate networks of eoxPL molecules, including HETE-PLs, which change membrane properties to enhance blood coagulation and contribute to the excessive clotting and immunoreactivity of patients with APS.
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Affiliation(s)
- Sarah N Lauder
- Systems Immunity Research Institute, Cardiff University, Heath Park, Cardiff CF14 4XN, UK.,Division of Infection and Immunity, Cardiff University, Cardiff CF14 4XN, UK
| | - Keith Allen-Redpath
- Systems Immunity Research Institute, Cardiff University, Heath Park, Cardiff CF14 4XN, UK.,Division of Infection and Immunity, Cardiff University, Cardiff CF14 4XN, UK
| | - David A Slatter
- Systems Immunity Research Institute, Cardiff University, Heath Park, Cardiff CF14 4XN, UK.,Division of Infection and Immunity, Cardiff University, Cardiff CF14 4XN, UK
| | - Maceler Aldrovandi
- Systems Immunity Research Institute, Cardiff University, Heath Park, Cardiff CF14 4XN, UK.,Division of Infection and Immunity, Cardiff University, Cardiff CF14 4XN, UK
| | - Anne O'Connor
- Systems Immunity Research Institute, Cardiff University, Heath Park, Cardiff CF14 4XN, UK.,Division of Infection and Immunity, Cardiff University, Cardiff CF14 4XN, UK
| | - Daniel Farewell
- Division of Population Medicine, Cardiff University, Cardiff CF14 4XN, UK
| | - Charles L Percy
- Systems Immunity Research Institute, Cardiff University, Heath Park, Cardiff CF14 4XN, UK.,Division of Infection and Immunity, Cardiff University, Cardiff CF14 4XN, UK
| | - Jessica E Molhoek
- Department of Clinical Chemistry and Haematology, University of Utrecht, University Medical Center Utrecht, Utrecht 3584 CX, Netherlands
| | - Sirpa Rannikko
- Department of Medical Microbiology and Immunology, Research Unit of Biomedicine, Finland and Medical Research Center, University of Oulu, P.O. Box 5000, Oulu 90220, Finland.,Nordlab Oulu, University Hospital, Oulu 90220, Finland
| | - Victoria J Tyrrell
- Systems Immunity Research Institute, Cardiff University, Heath Park, Cardiff CF14 4XN, UK.,Division of Infection and Immunity, Cardiff University, Cardiff CF14 4XN, UK
| | - Salvatore Ferla
- Welsh School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff CF14 4XN, UK
| | - Ginger L Milne
- Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37240, USA
| | - Alastair W Poole
- School of Physiology, Pharmacy and Neuroscience, Medical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Christopher P Thomas
- Systems Immunity Research Institute, Cardiff University, Heath Park, Cardiff CF14 4XN, UK.,Division of Infection and Immunity, Cardiff University, Cardiff CF14 4XN, UK.,Welsh School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff CF14 4XN, UK
| | - Samya Obaji
- Systems Immunity Research Institute, Cardiff University, Heath Park, Cardiff CF14 4XN, UK.,Division of Infection and Immunity, Cardiff University, Cardiff CF14 4XN, UK
| | - Philip R Taylor
- Systems Immunity Research Institute, Cardiff University, Heath Park, Cardiff CF14 4XN, UK.,Division of Infection and Immunity, Cardiff University, Cardiff CF14 4XN, UK
| | - Simon A Jones
- Systems Immunity Research Institute, Cardiff University, Heath Park, Cardiff CF14 4XN, UK.,Division of Infection and Immunity, Cardiff University, Cardiff CF14 4XN, UK
| | - Phillip G de Groot
- Department of Clinical Chemistry and Haematology, University of Utrecht, University Medical Center Utrecht, Utrecht 3584 CX, Netherlands
| | - Rolf T Urbanus
- Department of Clinical Chemistry and Haematology, University of Utrecht, University Medical Center Utrecht, Utrecht 3584 CX, Netherlands
| | - Sohvi Hörkkö
- Department of Medical Microbiology and Immunology, Research Unit of Biomedicine, Finland and Medical Research Center, University of Oulu, P.O. Box 5000, Oulu 90220, Finland.,Nordlab Oulu, University Hospital, Oulu 90220, Finland
| | - Stefan Uderhardt
- Department of Internal Medicine and Institute for Clinical Immunology, University Hospital Erlangen, Erlangen, Germany
| | - Jochen Ackermann
- Department of Internal Medicine and Institute for Clinical Immunology, University Hospital Erlangen, Erlangen, Germany
| | - P Vince Jenkins
- Institute of Molecular Medicine, St James's Hospital, Dublin, Ireland
| | - Andrea Brancale
- Welsh School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff CF14 4XN, UK
| | - Gerhard Krönke
- Department of Internal Medicine and Institute for Clinical Immunology, University Hospital Erlangen, Erlangen, Germany
| | - Peter W Collins
- Systems Immunity Research Institute, Cardiff University, Heath Park, Cardiff CF14 4XN, UK. .,Division of Infection and Immunity, Cardiff University, Cardiff CF14 4XN, UK
| | - Valerie B O'Donnell
- Systems Immunity Research Institute, Cardiff University, Heath Park, Cardiff CF14 4XN, UK. .,Division of Infection and Immunity, Cardiff University, Cardiff CF14 4XN, UK
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24
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Affiliation(s)
- Ejaife O Agbani
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, UK
| | - Ingeborg Hers
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, UK
| | - Alastair W Poole
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, UK
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25
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Abstract
Platelets are classically known for their roles in bleeding control and occlusive thrombus formation causing ischemic tissue damage. Recently, nonclassical roles for platelets have been described, many of which may be mediated by the heterogeneous cargo that platelets secrete from granular stores upon activation. Using an in vitro model of ischemic injury to ventricular cardiomyocytes, we observed that platelets, through secreted factors, delayed the rate of cardiomyocyte death during ischemia. This protective effect appeared independent of platelet dense granule cargo, but required α-granule components stromal cell-derived factor-1α and transforming growth factor-β1. Protein kinase C activity within cardiomyocytes was responsible for mediating the protective signals initiated by the released platelet cargo. Importantly, pretreating platelets with a P2Y
12
antagonist, but not the cyclooxygenase inhibitor aspirin, substantially attenuated this protective effect. These findings therefore reveal a paradoxically protective role for platelet activation during cardiac ischemia and could have important implications for the use of antiplatelet therapeutics in the management of myocardial infarction.
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Affiliation(s)
- Tony G Walsh
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, BS8 1TD, United Kingdom
| | - Alastair W Poole
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, BS8 1TD, United Kingdom
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26
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Battram AM, Durrant TN, Agbani EO, Heesom KJ, Paul DS, Piatt R, Poole AW, Cullen PJ, Bergmeier W, Moore SF, Hers I. The Phosphatidylinositol 3,4,5-trisphosphate (PI(3,4,5)P3) Binder Rasa3 Regulates Phosphoinositide 3-kinase (PI3K)-dependent Integrin αIIbβ3 Outside-in Signaling. J Biol Chem 2017; 292:1691-1704. [PMID: 27903653 PMCID: PMC5290945 DOI: 10.1074/jbc.m116.746867] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 11/14/2016] [Indexed: 11/16/2022] Open
Abstract
The class I PI3K family of lipid kinases plays an important role in integrin αIIbβ3 function, thereby supporting thrombus growth and consolidation. Here, we identify Ras/Rap1GAP Rasa3 (GAP1IP4BP) as a major phosphatidylinositol 3,4,5-trisphosphate-binding protein in human platelets and a key regulator of integrin αIIbβ3 outside-in signaling. We demonstrate that cytosolic Rasa3 translocates to the plasma membrane in a PI3K-dependent manner upon activation of human platelets. Expression of wild-type Rasa3 in integrin αIIbβ3-expressing CHO cells blocked Rap1 activity and integrin αIIbβ3-mediated spreading on fibrinogen. In contrast, Rap1GAP-deficient (P489V) and Ras/Rap1GAP-deficient (R371Q) Rasa3 had no effect. We furthermore show that two Rasa3 mutants (H794L and G125V), which are expressed in different mouse models of thrombocytopenia, lack both Ras and Rap1GAP activity and do not affect integrin αIIbβ3-mediated spreading of CHO cells on fibrinogen. Platelets from thrombocytopenic mice expressing GAP-deficient Rasa3 (H794L) show increased spreading on fibrinogen, which in contrast to wild-type platelets is insensitive to PI3K inhibitors. Together, these results support an important role for Rasa3 in PI3K-dependent integrin αIIbβ3-mediated outside-in signaling and cell spreading.
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Affiliation(s)
- Anthony M Battram
- From the School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, BS8 1TD, United Kingdom
| | - Tom N Durrant
- From the School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, BS8 1TD, United Kingdom
| | - Ejaife O Agbani
- From the School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, BS8 1TD, United Kingdom
| | - Kate J Heesom
- School of Biochemistry, University of Bristol, Bristol, BS8 1TD, United Kingdom
| | - David S Paul
- the McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514
| | - Raymond Piatt
- the McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514
| | - Alastair W Poole
- From the School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, BS8 1TD, United Kingdom
| | - Peter J Cullen
- School of Biochemistry, University of Bristol, Bristol, BS8 1TD, United Kingdom
| | - Wolfgang Bergmeier
- the McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514; Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27514
| | - Samantha F Moore
- From the School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, BS8 1TD, United Kingdom
| | - Ingeborg Hers
- From the School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, BS8 1TD, United Kingdom.
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27
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Crescente M, Pluthero FG, Li L, Lo RW, Walsh TG, Schenk MP, Holbrook LM, Louriero S, Ali MS, Vaiyapuri S, Falet H, Jones IM, Poole AW, Kahr WHA, Gibbins JM. Intracellular Trafficking, Localization, and Mobilization of Platelet-Borne Thiol Isomerases. Arterioscler Thromb Vasc Biol 2016; 36:1164-73. [PMID: 27079884 DOI: 10.1161/atvbaha.116.307461] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 03/28/2016] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Thiol isomerases facilitate protein folding in the endoplasmic reticulum, and several of these enzymes, including protein disulfide isomerase and ERp57, are mobilized to the surface of activated platelets, where they influence platelet aggregation, blood coagulation, and thrombus formation. In this study, we examined the synthesis and trafficking of thiol isomerases in megakaryocytes, determined their subcellular localization in platelets, and identified the cellular events responsible for their movement to the platelet surface on activation. APPROACH AND RESULTS Immunofluorescence microscopy imaging was used to localize protein disulfide isomerase and ERp57 in murine and human megakaryocytes at various developmental stages. Immunofluorescence microscopy and subcellular fractionation analysis were used to localize these proteins in platelets to a compartment distinct from known secretory vesicles that overlaps with an inner cell-surface membrane region defined by the endoplasmic/sarcoplasmic reticulum proteins calnexin and sarco/endoplasmic reticulum calcium ATPase 3. Immunofluorescence microscopy and flow cytometry were used to monitor thiol isomerase mobilization in activated platelets in the presence and absence of actin polymerization (inhibited by latrunculin) and in the presence or absence of membrane fusion mediated by Munc13-4 (absent in platelets from Unc13d(Jinx) mice). CONCLUSIONS Platelet-borne thiol isomerases are trafficked independently of secretory granule contents in megakaryocytes and become concentrated in a subcellular compartment near the inner surface of the platelet outer membrane corresponding to the sarco/endoplasmic reticulum of these cells. Thiol isomerases are mobilized to the surface of activated platelets via a process that requires actin polymerization but not soluble N-ethylmaleimide-sensitive fusion protein attachment receptor/Munc13-4-dependent vesicular-plasma membrane fusion.
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Affiliation(s)
- Marilena Crescente
- From the School of Biological Sciences, University of Reading, Reading, United Kingdom (M.C., M.P.S., L.M.H., S.L., M.S.A., S.V., I.M.J., J.M.G.); Program in Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada (F.G.P., L.L., R.W.L., W.H.A.K.); Departments of Paediatrics and Biochemistry, University of Toronto, Toronto, Ontario, Canada (R.W.L., W.H.A.K.); School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (T.G.W., A.W.P.); and Division of Hematology, Brigham and Women's Hospital, Department of Medicine, Harvard Medical School, Boston, MA (H.F.)
| | - Fred G Pluthero
- From the School of Biological Sciences, University of Reading, Reading, United Kingdom (M.C., M.P.S., L.M.H., S.L., M.S.A., S.V., I.M.J., J.M.G.); Program in Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada (F.G.P., L.L., R.W.L., W.H.A.K.); Departments of Paediatrics and Biochemistry, University of Toronto, Toronto, Ontario, Canada (R.W.L., W.H.A.K.); School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (T.G.W., A.W.P.); and Division of Hematology, Brigham and Women's Hospital, Department of Medicine, Harvard Medical School, Boston, MA (H.F.)
| | - Ling Li
- From the School of Biological Sciences, University of Reading, Reading, United Kingdom (M.C., M.P.S., L.M.H., S.L., M.S.A., S.V., I.M.J., J.M.G.); Program in Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada (F.G.P., L.L., R.W.L., W.H.A.K.); Departments of Paediatrics and Biochemistry, University of Toronto, Toronto, Ontario, Canada (R.W.L., W.H.A.K.); School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (T.G.W., A.W.P.); and Division of Hematology, Brigham and Women's Hospital, Department of Medicine, Harvard Medical School, Boston, MA (H.F.)
| | - Richard W Lo
- From the School of Biological Sciences, University of Reading, Reading, United Kingdom (M.C., M.P.S., L.M.H., S.L., M.S.A., S.V., I.M.J., J.M.G.); Program in Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada (F.G.P., L.L., R.W.L., W.H.A.K.); Departments of Paediatrics and Biochemistry, University of Toronto, Toronto, Ontario, Canada (R.W.L., W.H.A.K.); School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (T.G.W., A.W.P.); and Division of Hematology, Brigham and Women's Hospital, Department of Medicine, Harvard Medical School, Boston, MA (H.F.)
| | - Tony G Walsh
- From the School of Biological Sciences, University of Reading, Reading, United Kingdom (M.C., M.P.S., L.M.H., S.L., M.S.A., S.V., I.M.J., J.M.G.); Program in Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada (F.G.P., L.L., R.W.L., W.H.A.K.); Departments of Paediatrics and Biochemistry, University of Toronto, Toronto, Ontario, Canada (R.W.L., W.H.A.K.); School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (T.G.W., A.W.P.); and Division of Hematology, Brigham and Women's Hospital, Department of Medicine, Harvard Medical School, Boston, MA (H.F.)
| | - Michael P Schenk
- From the School of Biological Sciences, University of Reading, Reading, United Kingdom (M.C., M.P.S., L.M.H., S.L., M.S.A., S.V., I.M.J., J.M.G.); Program in Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada (F.G.P., L.L., R.W.L., W.H.A.K.); Departments of Paediatrics and Biochemistry, University of Toronto, Toronto, Ontario, Canada (R.W.L., W.H.A.K.); School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (T.G.W., A.W.P.); and Division of Hematology, Brigham and Women's Hospital, Department of Medicine, Harvard Medical School, Boston, MA (H.F.)
| | - Lisa M Holbrook
- From the School of Biological Sciences, University of Reading, Reading, United Kingdom (M.C., M.P.S., L.M.H., S.L., M.S.A., S.V., I.M.J., J.M.G.); Program in Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada (F.G.P., L.L., R.W.L., W.H.A.K.); Departments of Paediatrics and Biochemistry, University of Toronto, Toronto, Ontario, Canada (R.W.L., W.H.A.K.); School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (T.G.W., A.W.P.); and Division of Hematology, Brigham and Women's Hospital, Department of Medicine, Harvard Medical School, Boston, MA (H.F.)
| | - Silvia Louriero
- From the School of Biological Sciences, University of Reading, Reading, United Kingdom (M.C., M.P.S., L.M.H., S.L., M.S.A., S.V., I.M.J., J.M.G.); Program in Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada (F.G.P., L.L., R.W.L., W.H.A.K.); Departments of Paediatrics and Biochemistry, University of Toronto, Toronto, Ontario, Canada (R.W.L., W.H.A.K.); School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (T.G.W., A.W.P.); and Division of Hematology, Brigham and Women's Hospital, Department of Medicine, Harvard Medical School, Boston, MA (H.F.)
| | - Marfoua S Ali
- From the School of Biological Sciences, University of Reading, Reading, United Kingdom (M.C., M.P.S., L.M.H., S.L., M.S.A., S.V., I.M.J., J.M.G.); Program in Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada (F.G.P., L.L., R.W.L., W.H.A.K.); Departments of Paediatrics and Biochemistry, University of Toronto, Toronto, Ontario, Canada (R.W.L., W.H.A.K.); School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (T.G.W., A.W.P.); and Division of Hematology, Brigham and Women's Hospital, Department of Medicine, Harvard Medical School, Boston, MA (H.F.)
| | - Sakthivel Vaiyapuri
- From the School of Biological Sciences, University of Reading, Reading, United Kingdom (M.C., M.P.S., L.M.H., S.L., M.S.A., S.V., I.M.J., J.M.G.); Program in Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada (F.G.P., L.L., R.W.L., W.H.A.K.); Departments of Paediatrics and Biochemistry, University of Toronto, Toronto, Ontario, Canada (R.W.L., W.H.A.K.); School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (T.G.W., A.W.P.); and Division of Hematology, Brigham and Women's Hospital, Department of Medicine, Harvard Medical School, Boston, MA (H.F.)
| | - Hervé Falet
- From the School of Biological Sciences, University of Reading, Reading, United Kingdom (M.C., M.P.S., L.M.H., S.L., M.S.A., S.V., I.M.J., J.M.G.); Program in Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada (F.G.P., L.L., R.W.L., W.H.A.K.); Departments of Paediatrics and Biochemistry, University of Toronto, Toronto, Ontario, Canada (R.W.L., W.H.A.K.); School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (T.G.W., A.W.P.); and Division of Hematology, Brigham and Women's Hospital, Department of Medicine, Harvard Medical School, Boston, MA (H.F.)
| | - Ian M Jones
- From the School of Biological Sciences, University of Reading, Reading, United Kingdom (M.C., M.P.S., L.M.H., S.L., M.S.A., S.V., I.M.J., J.M.G.); Program in Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada (F.G.P., L.L., R.W.L., W.H.A.K.); Departments of Paediatrics and Biochemistry, University of Toronto, Toronto, Ontario, Canada (R.W.L., W.H.A.K.); School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (T.G.W., A.W.P.); and Division of Hematology, Brigham and Women's Hospital, Department of Medicine, Harvard Medical School, Boston, MA (H.F.)
| | - Alastair W Poole
- From the School of Biological Sciences, University of Reading, Reading, United Kingdom (M.C., M.P.S., L.M.H., S.L., M.S.A., S.V., I.M.J., J.M.G.); Program in Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada (F.G.P., L.L., R.W.L., W.H.A.K.); Departments of Paediatrics and Biochemistry, University of Toronto, Toronto, Ontario, Canada (R.W.L., W.H.A.K.); School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (T.G.W., A.W.P.); and Division of Hematology, Brigham and Women's Hospital, Department of Medicine, Harvard Medical School, Boston, MA (H.F.)
| | - Walter H A Kahr
- From the School of Biological Sciences, University of Reading, Reading, United Kingdom (M.C., M.P.S., L.M.H., S.L., M.S.A., S.V., I.M.J., J.M.G.); Program in Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada (F.G.P., L.L., R.W.L., W.H.A.K.); Departments of Paediatrics and Biochemistry, University of Toronto, Toronto, Ontario, Canada (R.W.L., W.H.A.K.); School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (T.G.W., A.W.P.); and Division of Hematology, Brigham and Women's Hospital, Department of Medicine, Harvard Medical School, Boston, MA (H.F.).
| | - Jonathan M Gibbins
- From the School of Biological Sciences, University of Reading, Reading, United Kingdom (M.C., M.P.S., L.M.H., S.L., M.S.A., S.V., I.M.J., J.M.G.); Program in Cell Biology, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada (F.G.P., L.L., R.W.L., W.H.A.K.); Departments of Paediatrics and Biochemistry, University of Toronto, Toronto, Ontario, Canada (R.W.L., W.H.A.K.); School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (T.G.W., A.W.P.); and Division of Hematology, Brigham and Women's Hospital, Department of Medicine, Harvard Medical School, Boston, MA (H.F.).
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28
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Mattheij NJA, Braun A, van Kruchten R, Castoldi E, Pircher J, Baaten CCFMJ, Wülling M, Kuijpers MJE, Köhler R, Poole AW, Schreiber R, Vortkamp A, Collins PW, Nieswandt B, Kunzelmann K, Cosemans JMEM, Heemskerk JWM. Survival protein anoctamin-6 controls multiple platelet responses including phospholipid scrambling, swelling, and protein cleavage. FASEB J 2016; 30:727-37. [PMID: 26481309 DOI: 10.1096/fj.15-280446] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2015] [Accepted: 10/05/2015] [Indexed: 11/11/2022]
Abstract
Scott syndrome is a rare bleeding disorder, characterized by altered Ca(2+)-dependent platelet signaling with defective phosphatidylserine (PS) exposure and microparticle formation, and is linked to mutations in the ANO6 gene, encoding anoctamin (Ano)6. We investigated how the complex platelet phenotype of this syndrome is linked to defective expression of Anos or other ion channels. Mice were generated with heterozygous of homozygous deficiency in Ano6, Ano1, or Ca(2+)-dependent KCa3.1 Gardos channel. Platelets from these mice were extensively analyzed on molecular functions and compared with platelets from a patient with Scott syndrome. Deficiency in Ano1 or Gardos channel did not reduce platelet responses compared with control mice (P > 0.1). In 2 mouse strains, deficiency in Ano6 resulted in reduced viability with increased bleeding time to 28.6 min (control 6.4 min, P < 0.05). Platelets from the surviving Ano6-deficient mice resembled platelets from patients with Scott syndrome in: 1) normal collagen-induced aggregate formation (P > 0.05) with reduced PS exposure (-65 to 90%); 2) lowered Ca(2+)-dependent swelling (-80%) and membrane blebbing (-90%); 3) reduced calpain-dependent protein cleavage (-60%); and 4) moderately affected apoptosis-dependent PS exposure. In conclusion, mouse deficiency of Ano6 but not of other channels affects viability and phenocopies the complex changes in platelets from hemostatically impaired patients with Scott syndrome.
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Affiliation(s)
- Nadine J A Mattheij
- *Department of Cell Biochemistry of Thrombosis and Haemostasis Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, Maastricht, The Netherlands; Department of Experimental Biomedicine, University Hospital and Rudolf Virchow Center, University of Würzburg, Würzburg, Germany; Walter Brendel Centre of Experimental Medicine and German Centre of Cardiovascular Research, Munich Heart Alliance, Ludwig-Maximilians-Universität München, München, Germany; Department of Developmental Biology, Centre for Medical Biotechnology, University of Duisburg-Essen, Duisburg-Essen, Germany; Aragon Institute of Health Sciences I+CS/IIS and ARAID, Zaragoza, Spain; School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom; Institute of Physiology, University of Regensburg, Regensburg, Germany; **Arthur Bloom Haemophilia Centre, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Attila Braun
- *Department of Cell Biochemistry of Thrombosis and Haemostasis Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, Maastricht, The Netherlands; Department of Experimental Biomedicine, University Hospital and Rudolf Virchow Center, University of Würzburg, Würzburg, Germany; Walter Brendel Centre of Experimental Medicine and German Centre of Cardiovascular Research, Munich Heart Alliance, Ludwig-Maximilians-Universität München, München, Germany; Department of Developmental Biology, Centre for Medical Biotechnology, University of Duisburg-Essen, Duisburg-Essen, Germany; Aragon Institute of Health Sciences I+CS/IIS and ARAID, Zaragoza, Spain; School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom; Institute of Physiology, University of Regensburg, Regensburg, Germany; **Arthur Bloom Haemophilia Centre, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Roger van Kruchten
- *Department of Cell Biochemistry of Thrombosis and Haemostasis Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, Maastricht, The Netherlands; Department of Experimental Biomedicine, University Hospital and Rudolf Virchow Center, University of Würzburg, Würzburg, Germany; Walter Brendel Centre of Experimental Medicine and German Centre of Cardiovascular Research, Munich Heart Alliance, Ludwig-Maximilians-Universität München, München, Germany; Department of Developmental Biology, Centre for Medical Biotechnology, University of Duisburg-Essen, Duisburg-Essen, Germany; Aragon Institute of Health Sciences I+CS/IIS and ARAID, Zaragoza, Spain; School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom; Institute of Physiology, University of Regensburg, Regensburg, Germany; **Arthur Bloom Haemophilia Centre, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Elisabetta Castoldi
- *Department of Cell Biochemistry of Thrombosis and Haemostasis Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, Maastricht, The Netherlands; Department of Experimental Biomedicine, University Hospital and Rudolf Virchow Center, University of Würzburg, Würzburg, Germany; Walter Brendel Centre of Experimental Medicine and German Centre of Cardiovascular Research, Munich Heart Alliance, Ludwig-Maximilians-Universität München, München, Germany; Department of Developmental Biology, Centre for Medical Biotechnology, University of Duisburg-Essen, Duisburg-Essen, Germany; Aragon Institute of Health Sciences I+CS/IIS and ARAID, Zaragoza, Spain; School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom; Institute of Physiology, University of Regensburg, Regensburg, Germany; **Arthur Bloom Haemophilia Centre, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Joachim Pircher
- *Department of Cell Biochemistry of Thrombosis and Haemostasis Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, Maastricht, The Netherlands; Department of Experimental Biomedicine, University Hospital and Rudolf Virchow Center, University of Würzburg, Würzburg, Germany; Walter Brendel Centre of Experimental Medicine and German Centre of Cardiovascular Research, Munich Heart Alliance, Ludwig-Maximilians-Universität München, München, Germany; Department of Developmental Biology, Centre for Medical Biotechnology, University of Duisburg-Essen, Duisburg-Essen, Germany; Aragon Institute of Health Sciences I+CS/IIS and ARAID, Zaragoza, Spain; School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom; Institute of Physiology, University of Regensburg, Regensburg, Germany; **Arthur Bloom Haemophilia Centre, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Constance C F M J Baaten
- *Department of Cell Biochemistry of Thrombosis and Haemostasis Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, Maastricht, The Netherlands; Department of Experimental Biomedicine, University Hospital and Rudolf Virchow Center, University of Würzburg, Würzburg, Germany; Walter Brendel Centre of Experimental Medicine and German Centre of Cardiovascular Research, Munich Heart Alliance, Ludwig-Maximilians-Universität München, München, Germany; Department of Developmental Biology, Centre for Medical Biotechnology, University of Duisburg-Essen, Duisburg-Essen, Germany; Aragon Institute of Health Sciences I+CS/IIS and ARAID, Zaragoza, Spain; School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom; Institute of Physiology, University of Regensburg, Regensburg, Germany; **Arthur Bloom Haemophilia Centre, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Manuela Wülling
- *Department of Cell Biochemistry of Thrombosis and Haemostasis Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, Maastricht, The Netherlands; Department of Experimental Biomedicine, University Hospital and Rudolf Virchow Center, University of Würzburg, Würzburg, Germany; Walter Brendel Centre of Experimental Medicine and German Centre of Cardiovascular Research, Munich Heart Alliance, Ludwig-Maximilians-Universität München, München, Germany; Department of Developmental Biology, Centre for Medical Biotechnology, University of Duisburg-Essen, Duisburg-Essen, Germany; Aragon Institute of Health Sciences I+CS/IIS and ARAID, Zaragoza, Spain; School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom; Institute of Physiology, University of Regensburg, Regensburg, Germany; **Arthur Bloom Haemophilia Centre, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Marijke J E Kuijpers
- *Department of Cell Biochemistry of Thrombosis and Haemostasis Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, Maastricht, The Netherlands; Department of Experimental Biomedicine, University Hospital and Rudolf Virchow Center, University of Würzburg, Würzburg, Germany; Walter Brendel Centre of Experimental Medicine and German Centre of Cardiovascular Research, Munich Heart Alliance, Ludwig-Maximilians-Universität München, München, Germany; Department of Developmental Biology, Centre for Medical Biotechnology, University of Duisburg-Essen, Duisburg-Essen, Germany; Aragon Institute of Health Sciences I+CS/IIS and ARAID, Zaragoza, Spain; School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom; Institute of Physiology, University of Regensburg, Regensburg, Germany; **Arthur Bloom Haemophilia Centre, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Ralf Köhler
- *Department of Cell Biochemistry of Thrombosis and Haemostasis Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, Maastricht, The Netherlands; Department of Experimental Biomedicine, University Hospital and Rudolf Virchow Center, University of Würzburg, Würzburg, Germany; Walter Brendel Centre of Experimental Medicine and German Centre of Cardiovascular Research, Munich Heart Alliance, Ludwig-Maximilians-Universität München, München, Germany; Department of Developmental Biology, Centre for Medical Biotechnology, University of Duisburg-Essen, Duisburg-Essen, Germany; Aragon Institute of Health Sciences I+CS/IIS and ARAID, Zaragoza, Spain; School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom; Institute of Physiology, University of Regensburg, Regensburg, Germany; **Arthur Bloom Haemophilia Centre, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Alastair W Poole
- *Department of Cell Biochemistry of Thrombosis and Haemostasis Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, Maastricht, The Netherlands; Department of Experimental Biomedicine, University Hospital and Rudolf Virchow Center, University of Würzburg, Würzburg, Germany; Walter Brendel Centre of Experimental Medicine and German Centre of Cardiovascular Research, Munich Heart Alliance, Ludwig-Maximilians-Universität München, München, Germany; Department of Developmental Biology, Centre for Medical Biotechnology, University of Duisburg-Essen, Duisburg-Essen, Germany; Aragon Institute of Health Sciences I+CS/IIS and ARAID, Zaragoza, Spain; School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom; Institute of Physiology, University of Regensburg, Regensburg, Germany; **Arthur Bloom Haemophilia Centre, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Rainer Schreiber
- *Department of Cell Biochemistry of Thrombosis and Haemostasis Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, Maastricht, The Netherlands; Department of Experimental Biomedicine, University Hospital and Rudolf Virchow Center, University of Würzburg, Würzburg, Germany; Walter Brendel Centre of Experimental Medicine and German Centre of Cardiovascular Research, Munich Heart Alliance, Ludwig-Maximilians-Universität München, München, Germany; Department of Developmental Biology, Centre for Medical Biotechnology, University of Duisburg-Essen, Duisburg-Essen, Germany; Aragon Institute of Health Sciences I+CS/IIS and ARAID, Zaragoza, Spain; School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom; Institute of Physiology, University of Regensburg, Regensburg, Germany; **Arthur Bloom Haemophilia Centre, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Andrea Vortkamp
- *Department of Cell Biochemistry of Thrombosis and Haemostasis Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, Maastricht, The Netherlands; Department of Experimental Biomedicine, University Hospital and Rudolf Virchow Center, University of Würzburg, Würzburg, Germany; Walter Brendel Centre of Experimental Medicine and German Centre of Cardiovascular Research, Munich Heart Alliance, Ludwig-Maximilians-Universität München, München, Germany; Department of Developmental Biology, Centre for Medical Biotechnology, University of Duisburg-Essen, Duisburg-Essen, Germany; Aragon Institute of Health Sciences I+CS/IIS and ARAID, Zaragoza, Spain; School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom; Institute of Physiology, University of Regensburg, Regensburg, Germany; **Arthur Bloom Haemophilia Centre, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Peter W Collins
- *Department of Cell Biochemistry of Thrombosis and Haemostasis Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, Maastricht, The Netherlands; Department of Experimental Biomedicine, University Hospital and Rudolf Virchow Center, University of Würzburg, Würzburg, Germany; Walter Brendel Centre of Experimental Medicine and German Centre of Cardiovascular Research, Munich Heart Alliance, Ludwig-Maximilians-Universität München, München, Germany; Department of Developmental Biology, Centre for Medical Biotechnology, University of Duisburg-Essen, Duisburg-Essen, Germany; Aragon Institute of Health Sciences I+CS/IIS and ARAID, Zaragoza, Spain; School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom; Institute of Physiology, University of Regensburg, Regensburg, Germany; **Arthur Bloom Haemophilia Centre, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Bernhard Nieswandt
- *Department of Cell Biochemistry of Thrombosis and Haemostasis Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, Maastricht, The Netherlands; Department of Experimental Biomedicine, University Hospital and Rudolf Virchow Center, University of Würzburg, Würzburg, Germany; Walter Brendel Centre of Experimental Medicine and German Centre of Cardiovascular Research, Munich Heart Alliance, Ludwig-Maximilians-Universität München, München, Germany; Department of Developmental Biology, Centre for Medical Biotechnology, University of Duisburg-Essen, Duisburg-Essen, Germany; Aragon Institute of Health Sciences I+CS/IIS and ARAID, Zaragoza, Spain; School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom; Institute of Physiology, University of Regensburg, Regensburg, Germany; **Arthur Bloom Haemophilia Centre, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Karl Kunzelmann
- *Department of Cell Biochemistry of Thrombosis and Haemostasis Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, Maastricht, The Netherlands; Department of Experimental Biomedicine, University Hospital and Rudolf Virchow Center, University of Würzburg, Würzburg, Germany; Walter Brendel Centre of Experimental Medicine and German Centre of Cardiovascular Research, Munich Heart Alliance, Ludwig-Maximilians-Universität München, München, Germany; Department of Developmental Biology, Centre for Medical Biotechnology, University of Duisburg-Essen, Duisburg-Essen, Germany; Aragon Institute of Health Sciences I+CS/IIS and ARAID, Zaragoza, Spain; School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom; Institute of Physiology, University of Regensburg, Regensburg, Germany; **Arthur Bloom Haemophilia Centre, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Judith M E M Cosemans
- *Department of Cell Biochemistry of Thrombosis and Haemostasis Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, Maastricht, The Netherlands; Department of Experimental Biomedicine, University Hospital and Rudolf Virchow Center, University of Würzburg, Würzburg, Germany; Walter Brendel Centre of Experimental Medicine and German Centre of Cardiovascular Research, Munich Heart Alliance, Ludwig-Maximilians-Universität München, München, Germany; Department of Developmental Biology, Centre for Medical Biotechnology, University of Duisburg-Essen, Duisburg-Essen, Germany; Aragon Institute of Health Sciences I+CS/IIS and ARAID, Zaragoza, Spain; School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom; Institute of Physiology, University of Regensburg, Regensburg, Germany; **Arthur Bloom Haemophilia Centre, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Johan W M Heemskerk
- *Department of Cell Biochemistry of Thrombosis and Haemostasis Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, Maastricht, The Netherlands; Department of Experimental Biomedicine, University Hospital and Rudolf Virchow Center, University of Würzburg, Würzburg, Germany; Walter Brendel Centre of Experimental Medicine and German Centre of Cardiovascular Research, Munich Heart Alliance, Ludwig-Maximilians-Universität München, München, Germany; Department of Developmental Biology, Centre for Medical Biotechnology, University of Duisburg-Essen, Duisburg-Essen, Germany; Aragon Institute of Health Sciences I+CS/IIS and ARAID, Zaragoza, Spain; School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom; Institute of Physiology, University of Regensburg, Regensburg, Germany; **Arthur Bloom Haemophilia Centre, School of Medicine, Cardiff University, Cardiff, United Kingdom
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Abstract
Platelets are critical for maintaining vascular hemostasis, but also play a major role in the formation of occlusive cardiovascular and cerebrovascular thrombi under disease conditions. Secretion of platelet alpha and dense granules is a requirement for efficient thrombus formation. Understanding and targeting the mechanisms of secretion is important to aid the development of effective antithrombotics. SNAP29 is a tSNARE found in platelets, but whose role has not been defined. Using a platelet-specific SNAP29 knockout mouse model, we assessed the role of SNAP29 in platelet secretion and function under standardized conditions and also in in vitro and in vivo thrombosis. The data showed no major defects in SNAP29-null platelets, but revealed a minor defect in α-granule secretion and a significant increase in embolization rate of thrombi in vivo. These data suggest that SNAP29 contributes to the regulation of platelet α-granule secretion and thrombus stability, possibly partially masked by functional redundancy with other tSNAREs, such as SNAP23.
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Affiliation(s)
- C M Williams
- a School of Physiology & Pharmacology , University of Bristol , Bristol , UK
| | - J S Savage
- a School of Physiology & Pharmacology , University of Bristol , Bristol , UK.,b Cancer Research UK Clinical Trials Unit (CRCTU), School of Cancer Sciences , University of Birmingham , Edgbaston, Birmingham , UK
| | - M T Harper
- a School of Physiology & Pharmacology , University of Bristol , Bristol , UK.,c Department of Pharmacology , University of Cambridge , Cambridge , UK
| | - S F Moore
- a School of Physiology & Pharmacology , University of Bristol , Bristol , UK
| | - I Hers
- a School of Physiology & Pharmacology , University of Bristol , Bristol , UK
| | - A W Poole
- a School of Physiology & Pharmacology , University of Bristol , Bristol , UK
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Williams CM, Harper MT, Goggs R, Walsh TG, Offermanns S, Poole AW. Leukemia-associated Rho guanine-nucleotide exchange factor is not critical for RhoA regulation, yet is important for platelet activation and thrombosis in mice. J Thromb Haemost 2015; 13:2102-7. [PMID: 26334261 PMCID: PMC4755168 DOI: 10.1111/jth.13129] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 08/12/2015] [Indexed: 12/20/2022]
Abstract
BACKGROUND RhoA is an important regulator of platelet responses downstream of Gα13 , yet we still know little about its regulation in platelets. Leukemia-associated Rho guanine-nucleotide exchange factor (GEF [LARG]), a RhoA GEF, is highly expressed in platelets and may constitute a major upstream activator of RhoA. To this end, it is important to determine the role of LARG in platelet function and thrombosis. METHODS AND RESULTS Using a platelet-specific gene knockout, we show that the absence of LARG results in a marked reduction in aggregation and dense-granule secretion in response to the thromboxane mimetic U46619 and proteinase-activated receptor 4-activating peptide, AYPGKF, but not to adenosine diphosphate. In a ferric chloride thrombosis model in vivo, this translated into a defect, under mild injury conditions. Importantly, agonist-induced RhoA activation was not affected by the absence of LARG, although basal activity was reduced, suggesting that LARG may play a housekeeper role in regulating constitutive RhoA activity. CONCLUSIONS LARG plays an important role in platelet function and thrombosis in vivo. However, although LARG may have a role in regulating the resting activation state of RhoA, its role in regulating platelet function may principally be through RhoA-independent pathways, possibly through other Rho family members.
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Affiliation(s)
- C M Williams
- School of Physiology & Pharmacology, University of Bristol, Bristol, UK
| | - M T Harper
- School of Physiology & Pharmacology, University of Bristol, Bristol, UK
| | - R Goggs
- School of Physiology & Pharmacology, University of Bristol, Bristol, UK
| | - T G Walsh
- School of Physiology & Pharmacology, University of Bristol, Bristol, UK
| | - S Offermanns
- Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - A W Poole
- School of Physiology & Pharmacology, University of Bristol, Bristol, UK
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31
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Agbani EO, van den Bosch MTJ, Brown E, Williams CM, Mattheij NJA, Cosemans JMEM, Collins PW, Heemskerk JWM, Hers I, Poole AW. Coordinated Membrane Ballooning and Procoagulant Spreading in Human Platelets. Circulation 2015; 132:1414-24. [PMID: 26330411 DOI: 10.1161/circulationaha.114.015036] [Citation(s) in RCA: 120] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 07/30/2015] [Indexed: 11/16/2022]
Abstract
BACKGROUND Platelets are central to the process of hemostasis, rapidly aggregating at sites of blood vessel injury and acting as coagulation nidus sites. On interaction with the subendothelial matrix, platelets are transformed into balloonlike structures as part of the hemostatic response. It remains unclear, however, how and why platelets generate these structures. We set out to determine the physiological relevance and cellular and molecular mechanisms underlying platelet membrane ballooning. METHODS AND RESULTS Using 4-dimensional live-cell imaging and electron microscopy, we show that human platelets adherent to collagen are transformed into phosphatidylserine-exposing balloonlike structures with expansive macro/microvesiculate contact surfaces, by a process that we termed procoagulant spreading. We reveal that ballooning is mechanistically and structurally distinct from membrane blebbing and involves disruption to the platelet microtubule cytoskeleton and inflation through fluid entry. Unlike blebbing, procoagulant ballooning is irreversible and a consequence of Na(+), Cl(-), and water entry. Furthermore, membrane ballooning correlated with microparticle generation. Inhibition of Na(+), Cl(-), or water entry impaired ballooning, procoagulant spreading, and microparticle generation, and it also diminished local thrombin generation. Human Scott syndrome platelets, which lack expression of Ano-6, also showed a marked reduction in membrane ballooning, consistent with a role for chloride entry in the process. Finally, the blockade of water entry by acetazolamide attenuated ballooning in vitro and markedly suppressed thrombus formation in vivo in a mouse model of thrombosis. CONCLUSIONS Ballooning and procoagulant spreading of platelets are driven by fluid entry into the cells, and are important for the amplification of localized coagulation in thrombosis.
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Affiliation(s)
- Ejaife O Agbani
- From School of Physiology & Pharmacology, University of Bristol, United Kingdom (E.O.A., M.T.J.v.d.B., E.B., C.M.W., I.H., A.W.P.; Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, The Netherlands (N.J.A.M., J.M.E.M.C., J.W.M.H.); and Welsh Blood Service and Arthur Bloom Haemophilia Centre, School of Medicine, Cardiff University, United Kingdom (P.W.C.).
| | - Marion T J van den Bosch
- From School of Physiology & Pharmacology, University of Bristol, United Kingdom (E.O.A., M.T.J.v.d.B., E.B., C.M.W., I.H., A.W.P.; Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, The Netherlands (N.J.A.M., J.M.E.M.C., J.W.M.H.); and Welsh Blood Service and Arthur Bloom Haemophilia Centre, School of Medicine, Cardiff University, United Kingdom (P.W.C.)
| | - Ed Brown
- From School of Physiology & Pharmacology, University of Bristol, United Kingdom (E.O.A., M.T.J.v.d.B., E.B., C.M.W., I.H., A.W.P.; Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, The Netherlands (N.J.A.M., J.M.E.M.C., J.W.M.H.); and Welsh Blood Service and Arthur Bloom Haemophilia Centre, School of Medicine, Cardiff University, United Kingdom (P.W.C.)
| | - Christopher M Williams
- From School of Physiology & Pharmacology, University of Bristol, United Kingdom (E.O.A., M.T.J.v.d.B., E.B., C.M.W., I.H., A.W.P.; Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, The Netherlands (N.J.A.M., J.M.E.M.C., J.W.M.H.); and Welsh Blood Service and Arthur Bloom Haemophilia Centre, School of Medicine, Cardiff University, United Kingdom (P.W.C.)
| | - Nadine J A Mattheij
- From School of Physiology & Pharmacology, University of Bristol, United Kingdom (E.O.A., M.T.J.v.d.B., E.B., C.M.W., I.H., A.W.P.; Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, The Netherlands (N.J.A.M., J.M.E.M.C., J.W.M.H.); and Welsh Blood Service and Arthur Bloom Haemophilia Centre, School of Medicine, Cardiff University, United Kingdom (P.W.C.)
| | - Judith M E M Cosemans
- From School of Physiology & Pharmacology, University of Bristol, United Kingdom (E.O.A., M.T.J.v.d.B., E.B., C.M.W., I.H., A.W.P.; Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, The Netherlands (N.J.A.M., J.M.E.M.C., J.W.M.H.); and Welsh Blood Service and Arthur Bloom Haemophilia Centre, School of Medicine, Cardiff University, United Kingdom (P.W.C.)
| | - Peter W Collins
- From School of Physiology & Pharmacology, University of Bristol, United Kingdom (E.O.A., M.T.J.v.d.B., E.B., C.M.W., I.H., A.W.P.; Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, The Netherlands (N.J.A.M., J.M.E.M.C., J.W.M.H.); and Welsh Blood Service and Arthur Bloom Haemophilia Centre, School of Medicine, Cardiff University, United Kingdom (P.W.C.)
| | - Johan W M Heemskerk
- From School of Physiology & Pharmacology, University of Bristol, United Kingdom (E.O.A., M.T.J.v.d.B., E.B., C.M.W., I.H., A.W.P.; Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, The Netherlands (N.J.A.M., J.M.E.M.C., J.W.M.H.); and Welsh Blood Service and Arthur Bloom Haemophilia Centre, School of Medicine, Cardiff University, United Kingdom (P.W.C.)
| | - Ingeborg Hers
- From School of Physiology & Pharmacology, University of Bristol, United Kingdom (E.O.A., M.T.J.v.d.B., E.B., C.M.W., I.H., A.W.P.; Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, The Netherlands (N.J.A.M., J.M.E.M.C., J.W.M.H.); and Welsh Blood Service and Arthur Bloom Haemophilia Centre, School of Medicine, Cardiff University, United Kingdom (P.W.C.)
| | - Alastair W Poole
- From School of Physiology & Pharmacology, University of Bristol, United Kingdom (E.O.A., M.T.J.v.d.B., E.B., C.M.W., I.H., A.W.P.; Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), University of Maastricht, The Netherlands (N.J.A.M., J.M.E.M.C., J.W.M.H.); and Welsh Blood Service and Arthur Bloom Haemophilia Centre, School of Medicine, Cardiff University, United Kingdom (P.W.C.).
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Bell KS, Al-Riyami L, Lumb FE, Britton GJ, Poole AW, Williams CM, Braun U, Leitges M, Harnett MM, Harnett W. The role of individual protein kinase C isoforms in mouse mast cell function and their targeting by the immunomodulatory parasitic worm product, ES-62. Immunol Lett 2015; 168:31-40. [PMID: 26343793 PMCID: PMC4643489 DOI: 10.1016/j.imlet.2015.09.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Revised: 07/28/2015] [Accepted: 09/01/2015] [Indexed: 12/31/2022]
Abstract
ES-62, a glycoprotein secreted by the filarial nematode Acanthocheilonema viteae, has been shown to modulate the immune system through subversion of signal transduction pathways operating in various immune system cells. With respect to human bone marrow-derived mast cells (BMMCs), ES-62 was previously shown to inhibit FcϵRI-mediated mast cell functional responses such as degranulation and pro-inflammatory cytokine release through a mechanism involving the degradation of PKC-α. At the same time, it was noted that the worm product was able to degrade certain other PKC isoforms but the significance of this was uncertain. In this study, we have employed PKC isoform KO mice to investigate the role of PKC-α, -β -ϵ, and -θ in mouse BMMCs in order to establish their involvement in mast cell-mediated responses and also, if their absence impacts on ES-62's activity. The data obtained support that in response to antigen cross-linking of IgE bound to FcϵRI, pro-inflammatory cytokine release is controlled in part by a partnership between one conventional and one novel isoform with PKC-α and -θ acting as positive regulators of IL-6 and TNF-α production, while PKC-β and ϵ act as negative regulators of such cytokines. Furthermore, ES-62 appears to target certain other PKC isoforms in addition to PKC-α to inhibit cytokine release and this may enable it to more efficiently inhibit mast cell responses.
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Affiliation(s)
- Kara S Bell
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, UK
| | - Lamyaa Al-Riyami
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, UK
| | - Felicity E Lumb
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, UK
| | - Graham J Britton
- School of Medical Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Alastair W Poole
- School of Medical Sciences, University of Bristol, Bristol BS8 1TD, UK
| | | | - Ursula Braun
- The Biotechnology Centre of Oslo, University of Oslo, Oslo 0349, Norway
| | - Michael Leitges
- The Biotechnology Centre of Oslo, University of Oslo, Oslo 0349, Norway
| | - Margaret M Harnett
- Centre for Immunobiology, Glasgow Biomedical Research Centre, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow G12 8TA, UK
| | - William Harnett
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, UK.
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Moore SF, Williams CM, Brown E, Blair TA, Harper MT, Coward RJ, Poole AW, Hers I. Loss of the insulin receptor in murine megakaryocytes/platelets causes thrombocytosis and alterations in IGF signalling. Cardiovasc Res 2015; 107:9-19. [PMID: 25902782 PMCID: PMC4476412 DOI: 10.1093/cvr/cvv132] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 04/03/2015] [Indexed: 12/21/2022] Open
Abstract
Aims Patients with conditions that are associated with insulin resistance such as obesity, type 2 diabetes mellitus, and polycystic ovary syndrome have an increased risk of thrombosis and a concurrent hyperactive platelet phenotype. Our aim was to determine whether insulin resistance of megakaryocytes/platelets promotes platelet hyperactivation. Methods and results We generated a conditional mouse model where the insulin receptor (IR) was specifically knocked out in megakaryocytes/platelets and performed ex vivo platelet activation studies in wild-type (WT) and IR-deficient platelets by measuring aggregation, integrin αIIbβ3 activation, and dense and α-granule secretion. Deletion of IR resulted in an increase in platelet count and volume, and blocked the action of insulin on platelet signalling and function. Platelet aggregation, granule secretion, and integrin αIIbβ3 activation in response to the glycoprotein VI (GPVI) agonist collagen-related peptide (CRP) were significantly reduced in platelets lacking IR. This was accompanied by a reduction in the phosphorylation of effectors downstream of GPVI. Interestingly, loss of IR also resulted in a reduction in insulin-like growth factor-1 (IGF-1)- and insulin-like growth factor-2 (IGF-2)-mediated phosphorylation of IRS-1, Akt, and GSK3β and priming of CRP-mediated platelet activation. Pharmacological inhibition of IR and the IGF-1 receptor in WT platelets recapitulated the platelet phenotype of IR-deficient platelets. Conclusions Deletion of IR (i) increases platelet count and volume, (ii) does not cause platelet hyperactivity, and (iii) reduces GPVI-mediated platelet function and platelet priming by IGF-1 and IGF-2.
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Affiliation(s)
- Samantha F Moore
- School of Physiology and Pharmacology, School of Medical Sciences, University of Bristol, University Walk, Medical Sciences Building, Bristol BS8 1TD, UK
| | - Christopher M Williams
- School of Physiology and Pharmacology, School of Medical Sciences, University of Bristol, University Walk, Medical Sciences Building, Bristol BS8 1TD, UK
| | - Edward Brown
- School of Physiology and Pharmacology, School of Medical Sciences, University of Bristol, University Walk, Medical Sciences Building, Bristol BS8 1TD, UK
| | - Thomas A Blair
- School of Physiology and Pharmacology, School of Medical Sciences, University of Bristol, University Walk, Medical Sciences Building, Bristol BS8 1TD, UK
| | - Matthew T Harper
- School of Physiology and Pharmacology, School of Medical Sciences, University of Bristol, University Walk, Medical Sciences Building, Bristol BS8 1TD, UK
| | - Richard J Coward
- School of Clinical Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol BS1 3NY, UK
| | - Alastair W Poole
- School of Physiology and Pharmacology, School of Medical Sciences, University of Bristol, University Walk, Medical Sciences Building, Bristol BS8 1TD, UK
| | - Ingeborg Hers
- School of Physiology and Pharmacology, School of Medical Sciences, University of Bristol, University Walk, Medical Sciences Building, Bristol BS8 1TD, UK
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Golebiewska EM, Harper MT, Williams CM, Savage JS, Goggs R, Fischer von Mollard G, Poole AW. Syntaxin 8 regulates platelet dense granule secretion, aggregation, and thrombus stability. J Biol Chem 2014; 290:1536-45. [PMID: 25404741 PMCID: PMC4340400 DOI: 10.1074/jbc.m114.602615] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Platelet secretion not only drives thrombosis and hemostasis, but also mediates a variety of other physiological and pathological processes. The ubiquitous SNARE machinery and a number of accessory proteins have been implicated in regulating secretion in platelet. Although several platelet SNAREs have been identified, further members of the SNARE family may be needed to fine-tune platelet secretion. In this study we identified expression of the t-SNARE syntaxin 8 (STX8) (Qc SNARE) in mouse and human platelets. In mouse studies, whereas STX8 was not essential for α-granule or lysosome secretion, Stx8−/− platelets showed a significant defect in dense granule secretion in response to thrombin and CRP. This was most pronounced at intermediate concentrations of agonists. They also showed an aggregation defect that could be rescued with exogenous ADP and increased embolization in Stx8−/− mice in vivo consistent with an important autocrine and paracrine role for ADP in aggregation and thrombus stabilization. STX8 therefore specifically contributes to dense granule secretion and represents another member of a growing family of genes that play distinct roles in regulating granule release from platelets and thus platelet function in thrombosis and hemostasis.
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Affiliation(s)
- Ewelina M Golebiewska
- From the School of Physiology and Pharmacology, Medical Sciences Building, University Walk, Bristol BS8 1TD, United Kingdom
| | - Matthew T Harper
- From the School of Physiology and Pharmacology, Medical Sciences Building, University Walk, Bristol BS8 1TD, United Kingdom
| | - Christopher M Williams
- From the School of Physiology and Pharmacology, Medical Sciences Building, University Walk, Bristol BS8 1TD, United Kingdom
| | - Joshua S Savage
- the School of Cancer Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Robert Goggs
- the Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, and
| | | | - Alastair W Poole
- From the School of Physiology and Pharmacology, Medical Sciences Building, University Walk, Bristol BS8 1TD, United Kingdom,
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35
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Abstract
Upon activation, platelets secrete more than 300 active substances from their intracellular granules. Platelet dense granule components, such as ADP and polyphosphates, contribute to haemostasis and coagulation, but also play a role in cancer metastasis. α-Granules contain multiple cytokines, mitogens, pro- and anti-inflammatory factors and other bioactive molecules that are essential regulators in the complex microenvironment of the growing thrombus but also contribute to a number of disease processes. Our understanding of the molecular mechanisms of secretion and the genetic regulation of granule biogenesis still remains incomplete. In this review we summarise our current understanding of the roles of platelet secretion in health and disease, and discuss some of the hypotheses that may explain how platelets may control the release of its many secreted components in a context-specific manner, to allow platelets to play multiple roles in health and disease.
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Affiliation(s)
- Ewelina M Golebiewska
- Medical Sciences Building, School of Physiology and Pharmacology, University of Bristol, University Walk, BS8 1TD Bristol, UK
| | - Alastair W Poole
- Medical Sciences Building, School of Physiology and Pharmacology, University of Bristol, University Walk, BS8 1TD Bristol, UK.
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Walsh TG, Harper MT, Poole AW. SDF-1α is a novel autocrine activator of platelets operating through its receptor CXCR4. Cell Signal 2014; 27:37-46. [PMID: 25283599 PMCID: PMC4265729 DOI: 10.1016/j.cellsig.2014.09.021] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 09/23/2014] [Indexed: 11/12/2022]
Abstract
Platelets store and secrete the chemokine stromal cell-derived factor (SDF)-1α upon platelet activation, but the ability of platelet-derived SDF-1α to signal in an autocrine/paracrine manner mediating functional platelet responses relevant to thrombosis and haemostasis is unknown. We sought to explore the role of platelet-derived SDF-1α and its receptors, CXCR4 and CXCR7 in facilitating platelet activation and determine the mechanism facilitating SDF-1α-mediated regulation of platelet function. Using human washed platelets, CXCR4 inhibition, but not CXCR7 blockade significantly abrogated collagen-mediated platelet aggregation, dense granule secretion and thromboxane (Tx) A2 production. Time-dependent release of SDF-1α from collagen-activated platelets supports a functional role for SDF-1α in this regard. Using an in vitro whole blood perfusion assay, collagen-induced thrombus formation was substantially reduced with CXCR4 inhibition. In washed platelets, recombinant SDF-1α in the range of 20–100 ng/mL− 1 could significantly enhance platelet aggregation responses to a threshold concentration of collagen. These enhancements were completely dependent on CXCR4, but not CXCR7, which triggered TxA2 production and dense granule secretion. Rises in cAMP were significantly blunted by SDF-1α, which could also enhance collagen-mediated Ca(2 +) mobilisation, both of which were mediated by CXCR4. This potentiating effect of SDF-1α primarily required TxA2 signalling acting upstream of dense granule secretion, whereas blockade of ADP signalling could only partially attenuate SDF-1α-induced platelet activation. Therefore, this study supports a potentially novel autocrine/paracrine role for platelet-derived SDF-1α during thrombosis and haemostasis, through a predominantly TxA2-dependent and ADP-independent pathway. Collagen-induced platelet aggregation, TxA2 production and dense granule secretion require CXCR4 signalling. CXCR4 regulates platelet thrombus formation. SDF-1α-induced changes in cAMP and Ca(2 +) signalling require CXCR4. SDF-1α, via CXCR4, enhances platelet activation responses to collagen, primarily through a TxA2-dependent and ADP-independent pathway.
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Affiliation(s)
- Tony G Walsh
- School of Physiology and Pharmacology, University of Bristol, Bristol, BS8 1TD, United Kingdom
| | - Matthew T Harper
- School of Physiology and Pharmacology, University of Bristol, Bristol, BS8 1TD, United Kingdom
| | - Alastair W Poole
- School of Physiology and Pharmacology, University of Bristol, Bristol, BS8 1TD, United Kingdom.
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Galea GL, Meakin LB, Williams CM, Hulin-Curtis SL, Lanyon LE, Poole AW, Price JS. Protein kinase Cα (PKCα) regulates bone architecture and osteoblast activity. J Biol Chem 2014; 289:25509-22. [PMID: 25070889 PMCID: PMC4162157 DOI: 10.1074/jbc.m114.580365] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Bones' strength is achieved and maintained through adaptation to load bearing. The role of the protein kinase PKCα in this process has not been previously reported. However, we observed a phenotype in the long bones of Prkca−/− female but not male mice, in which bone tissue progressively invades the medullary cavity in the mid-diaphysis. This bone deposition progresses with age and is prevented by disuse but unaffected by ovariectomy. Castration of male Prkca−/− but not WT mice results in the formation of small amounts of intramedullary bone. Osteoblast differentiation markers and Wnt target gene expression were up-regulated in osteoblast-like cells derived from cortical bone of female Prkca−/− mice compared with WT. Additionally, although osteoblastic cells derived from WT proliferate following exposure to estradiol or mechanical strain, those from Prkca−/− mice do not. Female Prkca−/− mice develop splenomegaly and reduced marrow GBA1 expression reminiscent of Gaucher disease, in which PKC involvement has been suggested previously. From these data, we infer that in female mice, PKCα normally serves to prevent endosteal bone formation stimulated by load bearing. This phenotype appears to be suppressed by testicular hormones in male Prkca−/− mice. Within osteoblastic cells, PKCα enhances proliferation and suppresses differentiation, and this regulation involves the Wnt pathway. These findings implicate PKCα as a target gene for therapeutic approaches in low bone mass conditions.
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Affiliation(s)
- Gabriel L Galea
- From the School of Veterinary Sciences, University of Bristol, Bristol BS2 8EJ, United Kingdom and
| | - Lee B Meakin
- From the School of Veterinary Sciences, University of Bristol, Bristol BS2 8EJ, United Kingdom and
| | - Christopher M Williams
- the School of Physiology and Pharmacology, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Sarah L Hulin-Curtis
- From the School of Veterinary Sciences, University of Bristol, Bristol BS2 8EJ, United Kingdom and
| | - Lance E Lanyon
- From the School of Veterinary Sciences, University of Bristol, Bristol BS2 8EJ, United Kingdom and
| | - Alastair W Poole
- the School of Physiology and Pharmacology, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Joanna S Price
- From the School of Veterinary Sciences, University of Bristol, Bristol BS2 8EJ, United Kingdom and
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Blair TA, Moore SF, Williams CM, Poole AW, Vanhaesebroeck B, Hers I. Phosphoinositide 3-kinases p110α and p110β have differential roles in insulin-like growth factor-1-mediated Akt phosphorylation and platelet priming. Arterioscler Thromb Vasc Biol 2014; 34:1681-8. [PMID: 24903091 DOI: 10.1161/atvbaha.114.303954] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
OBJECTIVE Platelet hyperactivity is a contributing factor in the pathogenesis of cardiovascular disease and can be induced by elevated levels of circulating growth factors, such as insulin-like growth factor-1 (IGF-1). IGF-1 is a primer that cannot stimulate platelet activation by itself, but in combination with physiological stimuli can potentiate platelet functional responses via a phosphoinositide 3-kinase-dependent mechanism. In this study, we explored the role of the phosphoinositide 3-kinase p110α isoform in IGF-1-mediated enhancement of platelet function. APPROACH AND RESULTS Using a platelet-specific p110α knockout murine model, we demonstrate that genetic deletion, similar to pharmacological inactivation of p110α, did not affect proteinase-activated receptor 4 signaling to Akt/protein kinase B but significantly reduced IGF-1-mediated Akt phosphorylation. The p110β inhibitor TGX-221 abolished IGF-1-induced Akt phosphorylation in p110α-deficient platelets, demonstrating that both p110α and p110β contribute to IGF-1-mediated Akt phosphorylation. Genetic deletion of p110α had no effect on IGF-1-mediated increases in thrombus formation on collagen and enhancement of proteinase-activated receptor 4-mediated integrin activation and α-granule secretion. In contrast, pharmacological inhibition of p110α blocked IGF-1-mediated potentiation of integrin activation and α-granule secretion. Functional enhancement by IGF-1 in p110α knockout samples was lost after TGX-221 treatment, suggesting that p110β drives priming in the absence of the p110α isoform. CONCLUSIONS Together, these results demonstrate that both p110α and p110β are involved in Akt signaling by IGF-1, but that it is the p110α isoform that is responsible for IGF-1-mediated potentiation of platelet function.
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Affiliation(s)
- Thomas A Blair
- From the School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (T.A.B., S.F.M., C.M.W., A.W.P., I.H.); and Research Department of Oncology, UCL Cancer Institute, University College London, London, United Kingdom (B.V.)
| | - Samantha F Moore
- From the School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (T.A.B., S.F.M., C.M.W., A.W.P., I.H.); and Research Department of Oncology, UCL Cancer Institute, University College London, London, United Kingdom (B.V.)
| | - Christopher M Williams
- From the School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (T.A.B., S.F.M., C.M.W., A.W.P., I.H.); and Research Department of Oncology, UCL Cancer Institute, University College London, London, United Kingdom (B.V.)
| | - Alastair W Poole
- From the School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (T.A.B., S.F.M., C.M.W., A.W.P., I.H.); and Research Department of Oncology, UCL Cancer Institute, University College London, London, United Kingdom (B.V.)
| | - Bart Vanhaesebroeck
- From the School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (T.A.B., S.F.M., C.M.W., A.W.P., I.H.); and Research Department of Oncology, UCL Cancer Institute, University College London, London, United Kingdom (B.V.)
| | - Ingeborg Hers
- From the School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom (T.A.B., S.F.M., C.M.W., A.W.P., I.H.); and Research Department of Oncology, UCL Cancer Institute, University College London, London, United Kingdom (B.V.).
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van den Bosch MTJ, Poole AW, Hers I. Cytohesin-2 phosphorylation by protein kinase C relieves the constitutive suppression of platelet dense granule secretion by ADP-ribosylation factor 6. J Thromb Haemost 2014; 12:726-35. [PMID: 24581425 PMCID: PMC4238808 DOI: 10.1111/jth.12542] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 02/19/2014] [Indexed: 11/30/2022]
Abstract
BACKGROUND Protein kinase C (PKC) is a major regulator of platelet function and secretion. The underlying molecular pathway from PKC to secretion, however, is poorly understood. By a proteomics screen we identified the guanine nucleotide exchange factor cytohesin-2 as a candidate PKC substrate. OBJECTIVES We aimed to validate cytohesin-2 as a PKC substrate in platelets and to determine its role in granule secretion and other platelet responses. METHODS AND RESULTS Immunoprecipitation was performed with a phosphoserine PKC substrate antibody followed by mass spectrometry, leading to the identification of cytohesin-2. By western blotting we showed that different agonists induced cytohesin-2 phosphorylation by PKC. Protein function was investigated using a pharmacological approach. The cytohesin inhibitor SecinH3 significantly enhanced platelet dense granule secretion and aggregation, as measured by lumi-aggregometry. Flow cytometry data indicate that α-granule release and integrin αII b β3 activation were not affected by cytohesin-2 inhibition. Lysosome secretion was assessed by a colorimetric assay and was also unchanged. As shown by western blotting, ARF6 interacted with cytohesin-2 and was present in an active GTP-bound form under basal conditions. Upon platelet stimulation, this interaction was largely lost and ARF6 activation decreased, both of which could be rescued by PKC inhibition. CONCLUSIONS Cytohesin-2 constitutively suppresses platelet dense granule secretion and aggregation by keeping ARF6 in a GTP-bound state. PKC-mediated phosphorylation of cytohesin-2 relieves this inhibitory effect, thereby promoting platelet secretion and aggregation.
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Harper MT, Poole AW. Chloride channels are necessary for full platelet phosphatidylserine exposure and procoagulant activity. Cell Death Dis 2013; 4:e969. [PMID: 24357800 PMCID: PMC3877565 DOI: 10.1038/cddis.2013.495] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 10/16/2013] [Accepted: 11/08/2013] [Indexed: 02/07/2023]
Abstract
Platelets enhance thrombin generation at sites of vascular injury by exposing phosphatidylserine during necrosis-like cell death. Anoctamin 6 (Ano6) is required for Ca(2+)-dependent phosphatidylserine exposure and is defective in patients with Scott syndrome, a rare bleeding disorder. Ano6 may also form Cl(-) channels, though the role of Cl(-) fluxes in platelet procoagulant activity has not been explored. We found that Cl(-) channel blockers or removal of extracellular Cl(-) inhibited agonist-induced phosphatidylserine exposure. However, this was not due to direct inhibition of Ca(2+)-dependent scrambling since Ca(2+) ionophore-induced phosphatidylserine exposure was normal. This implies that the role of Ano6 in Ca(2+-)dependent PS exposure is likely to differ from any putative function of Ano6 as a Cl(-) channel. Instead, Cl(-) channel blockade inhibited agonist-induced Ca(2+) entry. Importantly, Cl(-) channel blockers also prevented agonist-induced membrane hyperpolarization, resulting in depolarization. We propose that Cl(-) entry through Cl(-) channels is required for this hyperpolarization, maintaining the driving force for Ca(2+) entry and triggering full phosphatidylserine exposure. This demonstrates a novel role for Cl(-) channels in controlling platelet death and procoagulant activity.
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Affiliation(s)
- M T Harper
- School of Physiology and Pharmacology, Bristol Heart Institute, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - A W Poole
- School of Physiology and Pharmacology, Bristol Heart Institute, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
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Abstract
Upon activation by extracellular matrix components or soluble agonists, platelets release in excess of 300 active molecules from intracellular granules. Those factors can both activate further platelets and mediate a range of responses in other cells. The complex microenvironment of a growing thrombus, as well as platelets' roles in both physiological and pathological processes, require platelet secretion to be highly spatially and temporally regulated to ensure appropriate responses to a range of stimuli. However, how this regulation is achieved remains incompletely understood. In this review we outline the importance of regulated secretion in thrombosis as well as in 'novel' scenarios beyond haemostasis and give a detailed summary of what is known about the molecular mechanisms of platelet exocytosis. We also discuss a number of theories of how different cargoes could be released in a tightly orchestrated manner, allowing complex interactions between platelets and their environment.
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Affiliation(s)
- Ewelina M Golebiewska
- School of Physiology and Pharmacology, Bristol Heart Institute, University of Bristol, Bristol, UK
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Goggs R, Harper MT, Pope RJ, Savage JS, Williams CM, Mundell SJ, Heesom KJ, Bass M, Mellor H, Poole AW. RhoG protein regulates platelet granule secretion and thrombus formation in mice. J Biol Chem 2013; 288:34217-34229. [PMID: 24106270 PMCID: PMC3837162 DOI: 10.1074/jbc.m113.504100] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Rho GTPases such as Rac, RhoA, and Cdc42 are vital for normal platelet function, but the role of RhoG in platelets has not been studied. In other cells, RhoG orchestrates processes integral to platelet function, including actin cytoskeletal rearrangement and membrane trafficking. We therefore hypothesized that RhoG would play a critical role in platelets. Here, we show that RhoG is expressed in human and mouse platelets and is activated by both collagen-related peptide (CRP) and thrombin stimulation. We used RhoG(-/-) mice to study the function of RhoG in platelets. Integrin activation and aggregation were reduced in RhoG(-/-) platelets stimulated by CRP, but responses to thrombin were normal. The central defect in RhoG(-/-) platelets was reduced secretion from α-granules, dense granules, and lysosomes following CRP stimulation. The integrin activation and aggregation defects could be rescued by ADP co-stimulation, indicating that they are a consequence of diminished dense granule secretion. Defective dense granule secretion in RhoG(-/-) platelets limited recruitment of additional platelets to growing thrombi in flowing blood in vitro and translated into reduced thrombus formation in vivo. Interestingly, tail bleeding times were normal in RhoG(-/-) mice, suggesting that the functions of RhoG in platelets are particularly relevant to thrombotic disorders.
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Affiliation(s)
- Robert Goggs
- School of Physiology and Pharmacology, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Matthew T Harper
- School of Physiology and Pharmacology, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Robert J Pope
- School of Physiology and Pharmacology, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Joshua S Savage
- School of Physiology and Pharmacology, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Christopher M Williams
- School of Physiology and Pharmacology, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Stuart J Mundell
- School of Physiology and Pharmacology, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Kate J Heesom
- Proteomics Facility, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Mark Bass
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Harry Mellor
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Alastair W Poole
- School of Physiology and Pharmacology, University of Bristol, Bristol BS8 1TD, United Kingdom.
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Harper MT, Savage JS, Poole AW. Comment on "Platelet-derived nucleotides promote tumor cell transendothelial migration and metastasis via P2Y2 receptor" by Schumacher et al. Cancer Cell 2013; 24:287. [PMID: 24029227 DOI: 10.1016/j.ccr.2013.08.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 08/21/2013] [Accepted: 08/21/2013] [Indexed: 01/02/2023]
Affiliation(s)
- Matthew T Harper
- School of Physiology and Pharmacology, Bristol Heart Institute, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK.
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Savage JS, Williams CM, Konopatskaya O, Hers I, Harper MT, Poole AW. Munc13-4 is critical for thrombosis through regulating release of ADP from platelets. J Thromb Haemost 2013; 11:771-5. [PMID: 23331318 DOI: 10.1111/jth.12138] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Accepted: 12/20/2012] [Indexed: 01/19/2023]
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Abstract
Proplatelet formation is a part of the intricate process by which platelets are generated by their precursor cell, the megakaryocyte. The processes that drive megakaryocyte maturation and platelet production are however still not well understood. The protein kinase C (PKC) family of serine/threonine kinases has been demonstrated as an important regulator of megakaryocyte maturation and proplatelet formation, but little investigation has been made on the individual isoforms. We have previously shown, in mouse models, that PKCα plays a vital role in regulating platelet function, so in this study we aimed to investigate the role of PKCα in megakaryocyte function using the same Prkca(-)(/)(-) mice. We assessed the role of global PKC and specifically PKCα in proplatelet formation in vitro, analyzed polyploidy in Prkca(-)(/)(-)-derived megakaryocytes and followed platelet recovery in platelet-depleted Prkca(-)(/)(-) mice. We show reduced proplatelet formation in the presence of global PKC blockade. However, in the presence of a selective classical PKC isoform inhibitor, Go6976, proplatelet formation was conversely enhanced. PKCα null megakaryocytes also showed enhanced proplatelet formation, as well as a shift to greater polyploidy. In vivo, platelet production was enhanced in response to experimentally induced immune thrombocytopenia. In conclusion, our data indicate that classical PKC isoforms, and more specifically PKCα, are negative regulators of proplatelet formation. PKCα appears to negatively regulate endomitosis, with the enhanced polyploidy observed in Prkca(-)(/)(-)-derived megakaryocytes. In vivo, these observations may culminate in the observed ability of Prkca(-)(/)(-) mice to recover more rapidly from a thrombocytopenic insult.
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Affiliation(s)
- Christopher M Williams
- School of Physiology and Pharmacology, Bristol Heart Institute, Bristol Platelet Group, Medical Sciences Building, University of Bristol, University Walk , Bristol, BS8 1TD , UK
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Abstract
Background Formation of filopodia and other shape change events are vital for platelet hemostatic function. The mechanisms regulating filopodia formation by platelets are incompletely understood however. In particular the small GTPase responsible for initiating filopodia formation by platelets remains elusive. The canonical pathway involving Cdc42 is not essential for filopodia formation in mouse platelets. The small GTPase Rif (RhoF) provides an alternative route to filopodia generation in other cell types and is expressed in both human and mouse platelets. Hypothesis/Objective We hypothesized that Rif might be responsible for generating filopodia by platelets and generated a novel knockout mouse model to investigate the functional role of Rif in platelets. Methodology/Principal Findings Constitutive RhoF−/− mice are viable and have normal platelet, leukocyte and erythrocyte counts and indices. RhoF−/− platelets form filopodia and spread normally on various agonist surfaces in static conditions and under arterial shear. In addition, RhoF−/− platelets have normal actin dynamics, are able to activate and aggregate normally and secrete from alpha and dense granules in response to collagen related peptide and thrombin stimulation. Conclusions The small GTPase Rif does not appear to be critical for platelet function in mice. Functional overlap between Rif and other small GTPases may be responsible for the non-essential role of Rif in platelets.
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Affiliation(s)
- Robert Goggs
- School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom
| | - Joshua S. Savage
- School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom
| | - Harry Mellor
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | - Alastair W. Poole
- School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom
- * E-mail:
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Abstract
Background The motor protein myosin Va plays an important role in the trafficking of intracellular vesicles. Mutation of the Myo5a gene causes Griscelli syndrome type 1 in humans and the dilute phenotype in mice, which are both characterised by pigment dilution and neurological defects as a result of impaired vesicle transport in melanocytes and neuroendocrine cells. The role of myosin Va in platelets is currently unknown. Rab27 has been shown to be associated with myosin Va cargo vesicles and is known to be important in platelet dense granule biogenesis and secretion, a crucial event in thrombus formation. Therefore, we hypothesised that myosin Va may regulate granule secretion or formation in platelets. Methodology/Principal Findings Platelet function was studied in vitro using a novel Myo5a gene deletion mouse model. Myo5a−/− platelets were devoid of myosin Va, as determined by immunoblotting, and exhibited normal expression of surface markers. We assessed dense granule, α-granule and lysosomal secretion, integrin αIIbβ3 activation, Ca2+ signalling, and spreading on fibrinogen in response to collagen-related peptide or the PAR4 agonist, AYPGKF in washed mouse platelets lacking myosin Va or wild-type platelets. Surprisingly, Myo5a−/− platelets showed no significant functional defects in these responses, or in the numbers of dense and α-granules expressed. Conclusion Despite the importance of myosin Va in vesicle transport in other cells, our data demonstrate this motor protein has no non-redundant role in the secretion of dense and α-granules or other functional responses in platelets.
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Affiliation(s)
- Matthew T. Harper
- School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom
| | | | - Ingeborg Hers
- School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom
| | - Alastair W. Poole
- School of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom
- * E-mail:
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Moore SF, van den Bosch MTJ, Hunter RW, Sakamoto K, Poole AW, Hers I. Dual regulation of glycogen synthase kinase 3 (GSK3)α/β by protein kinase C (PKC)α and Akt promotes thrombin-mediated integrin αIIbβ3 activation and granule secretion in platelets. J Biol Chem 2012; 288:3918-28. [PMID: 23239877 PMCID: PMC3567645 DOI: 10.1074/jbc.m112.429936] [Citation(s) in RCA: 112] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Glycogen synthase kinase-3 is a Ser/Thr kinase, tonically active in resting cells but inhibited by phosphorylation of an N-terminal Ser residue (Ser21 in GSK3α and Ser9 in GSK3β) in response to varied external stimuli. Recent work suggests that GSK3 functions as a negative regulator of platelet function, but how GSK3 is regulated in platelets has not been examined in detail. Here, we show that early thrombin-mediated GSK3 phosphorylation (0–30 s) was blocked by PKC inhibitors and largely absent in platelets from PKCα knock-out mice. In contrast, late (2–5 min) GSK3 phosphorylation was dependent on the PI3K/Akt pathway. Similarly, early thrombin-mediated inhibition of GSK3 activity was blocked in PKCα knock-out platelets, whereas the Akt inhibitor MK2206 reduced late thrombin-mediated GSK3 inhibition and largely prevented GSK3 inhibition in PKCα knock-out platelets. More importantly, GSK3 phosphorylation contributes to platelet function as knock-in mice where GSK3α Ser21 and GSK3β Ser9 were mutated to Ala showed a significant reduction in PAR4-mediated platelet aggregation, fibrinogen binding, and P-selectin expression, whereas the GSK3 inhibitor CHIR99021 enhanced these responses. Together, these results demonstrate that PKCα and Akt modulate platelet function by phosphorylating and inhibiting GSK3α/β, thereby relieving the negative effect of GSK3α/β on thrombin-mediated platelet activation.
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Affiliation(s)
- Samantha F Moore
- School of Physiology and Pharmacology, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, United Kingdom
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Steele BM, Harper MT, Smolenski AP, Alkazemi N, Poole AW, Fitzgerald DJ, Maguire PB. WNT-3a modulates platelet function by regulating small GTPase activity. FEBS Lett 2012; 586:2267-72. [PMID: 22705156 DOI: 10.1016/j.febslet.2012.05.060] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Revised: 05/04/2012] [Accepted: 05/23/2012] [Indexed: 12/13/2022]
Abstract
Here we provide evidence that WNT-3a modulates platelet function by regulating the activity of four key GTPase proteins: Rap1, Cdc42, Rac1 and RhoA. We observe WNT-3a to differentially regulate small GTPase activity in platelets, promoting the GDP-bound form of Rap1b to inhibit integrin-α(IIb)β(3) adhesion, while concomitantly increasing Cdc42 and Rac1-GTP levels thereby disrupting normal platelet spreading. We demonstrate that Daam-1 interacts with Dishevelled upon platelet activation, which correlates with increased RhoA-GTP levels. Upon pre-treatment with WNT-3a, this complex disassociates, concurrent with a reduction in RhoA-GTP. Together these data implicate WNT-3a as a novel upstream regulator of small GTPase activity in platelets.
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Affiliation(s)
- Brian M Steele
- UCD Conway Institute, University College Dublin, Belfield, Dublin D4, Ireland.
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Abstract
OBJECTIVE To review the receptors and signal transduction pathways involved in platelet plug formation and to highlight links between platelets, leukocytes, endothelium, and the coagulation system. DATA SOURCES Original studies, review articles, and book chapters in the human and veterinary medical fields. DATA SYNTHESIS Platelets express numerous surface receptors. Critical among these are glycoprotein VI, the glycoprotein Ib-IX-V complex, integrin α(IIb) β(3) , and the G-protein-coupled receptors for thrombin, ADP, and thromboxane. Activation of these receptors leads to various important functional events, in particular activation of the principal adhesion receptor α(IIb) β(3) . Integrin activation allows binding of ligands such as fibrinogen, mediating platelet-platelet interaction in the process of aggregation. Signals activated by these receptors also couple to 3 other important functional events, secretion of granule contents, change in cell shape through cytoskeletal rearrangement, and procoagulant membrane expression. These processes generate a stable thrombus to limit blood loss and promote restoration of endothelial integrity. CONCLUSIONS Improvements in our understanding of how platelets operate through their signaling networks are critical for diagnosis of unusual primary hemostatic disorders and for rational antithrombotic drug design.
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Affiliation(s)
- Robert Goggs
- School of Physiology and Pharmacology, Faculty of Medical and Veterinary Sciences, University of Bristol, UK.
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