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Genome-wide analyses of early-onset acute myocardial infarction identify 29 novel loci by whole genome sequencing. Hum Genet 2023; 142:231-243. [PMID: 36336746 DOI: 10.1007/s00439-022-02495-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 10/09/2022] [Indexed: 11/08/2022]
Abstract
Early-onset acute myocardial infarction (AMI) may have a higher genetic predisposition than late-onset AMI. The present study aimed to identify and characterize germline variants that affect early-onset AMI using whole-genome sequencing (WGS). We performed a genome-wide association study based on the WGS of 1239 Koreans, including 596 early-onset AMI patients and 643 healthy individuals. Patients with AMI who underwent percutaneous coronary intervention (PCI) caused by atherothrombotic occlusive lesions were included in the study. A total of 29 novel loci were found to be associated with early-onset AMI. These loci are involved in thrombosis, fibrinolysis, inflammation, and lipid metabolism. One of the associated single nucleotide variants (SNVs), rs1614576, located upstream of PRKCB, is known to be associated with thrombus formation. Additionally, the results revealed a novel locus, rs78631167, located upstream of PLAUR which plays a critical role in regulating plasminogen activation and is related to fibrinolysis. The association between early-onset AMI and rs9357455, which is located upstream of PHACTR1 and regulates inflammation in AMI, was found. Moreover, we identified a lipid metabolism related genetic risk locus, rs5072, in the APOA1-AS gene. This study provides new evidence supporting the genetic association between early-onset AMI and thrombosis and fibrinolysis, as well as inflammation and lipid metabolism, by analyzing the whole-genome of 596 patients with early-onset AMI who have been treated with PCI. Our findings highlight potential genetic markers for the prediction and management of AMI, as well as for understanding the etiology of AMI.
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2
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Harper MT. Platelet-Derived Extracellular Vesicles in Arterial Thrombosis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1418:259-275. [PMID: 37603285 DOI: 10.1007/978-981-99-1443-2_17] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/22/2023]
Abstract
Blood platelets are necessary for normal haemostasis but also form life-threatening arterial thrombi when atherosclerotic plaques rupture. Activated platelets release many extracellular vesicles during thrombosis. Phosphatidylserine-exposing microparticles promote coagulation. Small exosomes released during granule secretion deliver cargoes including microRNAs to cells throughout the cardiovascular system. Here, we discuss the mechanisms by which platelets release these extracellular vesicles, together with the possibility of inhibiting this release as an antithrombotic strategy.
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Affiliation(s)
- Matthew T Harper
- Department of Pharmacology, University of Cambridge, Cambridge, UK.
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3
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Modulation of Glycoprotein VI and Its Downstream Signaling Pathways as an Antiplatelet Target. Int J Mol Sci 2022; 23:ijms23179882. [PMID: 36077280 PMCID: PMC9456422 DOI: 10.3390/ijms23179882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 07/06/2022] [Accepted: 07/11/2022] [Indexed: 11/16/2022] Open
Abstract
Antiplatelet therapy aims to reduce the risk of thrombotic events while maintaining hemostasis. A promising current approach is the inhibition of platelet glycoprotein GPVI-mediated adhesion pathways; pathways that do not involve coagulation. GPVI is a signaling receptor integral for collagen-induced platelet activation and participates in the thrombus consolidation process, being a suitable target for thrombosis prevention. Considering this, the blocking or antibody-mediated depletion of GPVI is a promising antiplatelet therapy for the effective and safe treatment of thrombotic diseases without a significant risk of bleeding and impaired hemostatic plug formation. This review describes the current knowledge concerning pharmaceutical approaches to platelet GPVI modulation and its downstream signaling pathways in this context.
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4
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Veuthey L, Aliotta A, Bertaggia Calderara D, Pereira Portela C, Alberio L. Mechanisms Underlying Dichotomous Procoagulant COAT Platelet Generation-A Conceptual Review Summarizing Current Knowledge. Int J Mol Sci 2022; 23:ijms23052536. [PMID: 35269679 PMCID: PMC8910683 DOI: 10.3390/ijms23052536] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/19/2022] [Accepted: 02/21/2022] [Indexed: 12/23/2022] Open
Abstract
Procoagulant platelets are a subtype of activated platelets that sustains thrombin generation in order to consolidate the clot and stop bleeding. This aspect of platelet activation is gaining more and more recognition and interest. In fact, next to aggregating platelets, procoagulant platelets are key regulators of thrombus formation. Imbalance of both subpopulations can lead to undesired thrombotic or bleeding events. COAT platelets derive from a common pro-aggregatory phenotype in cells capable of accumulating enough cytosolic calcium to trigger specific pathways that mediate the loss of their aggregating properties and the development of new adhesive and procoagulant characteristics. Complex cascades of signaling events are involved and this may explain why an inter-individual variability exists in procoagulant potential. Nowadays, we know the key agonists and mediators underlying the generation of a procoagulant platelet response. However, we still lack insight into the actual mechanisms controlling this dichotomous pattern (i.e., procoagulant versus aggregating phenotype). In this review, we describe the phenotypic characteristics of procoagulant COAT platelets, we detail the current knowledge on the mechanisms of the procoagulant response, and discuss possible drivers of this dichotomous diversification, in particular addressing the impact of the platelet environment during in vivo thrombus formation.
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5
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Limami Y, Senhaji N, Zaid N, Khalki L, Naya A, Hajjaj-Hassouni N, Jalali F, Oudghiri M, Zaid Y. PKC-Delta-Dependent Pathways Contribute to the Exacerbation of the Platelet Activity in Crohn's Disease. Semin Thromb Hemost 2021; 48:246-250. [PMID: 34749401 DOI: 10.1055/s-0041-1736571] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Youness Limami
- Department of Biology, Faculty of Sciences Ain Chock, Immunology and Biodiversity Laboratory, Hassan II University, Casablanca.,Department of Medicine, Research Center of Abulcasis University of Health Sciences, Rabat, Morocco
| | - Nezha Senhaji
- Faculty of Medicine, Laboratory of Genetic and Molecular Pathology, Hassan II University, Casablanca, Morocco
| | - Nabil Zaid
- Department of Biology, Faculty of Sciences, Mohammed V University in Rabat, Rabat, Morocco
| | - Loubna Khalki
- Faculty of Medicine, Research Center, Mohammed VI University of Health Sciences (UM6SS), Casablanca, Morocco
| | - Abdallah Naya
- Department of Biology, Faculty of Sciences Ain Chock, Immunology and Biodiversity Laboratory, Hassan II University, Casablanca
| | | | - Farid Jalali
- Department of Gastroenterology, Saddleback Medical Group, Laguna Hills, California
| | - Mounia Oudghiri
- Department of Biology, Faculty of Sciences Ain Chock, Immunology and Biodiversity Laboratory, Hassan II University, Casablanca
| | - Younes Zaid
- Department of Biology, Faculty of Sciences Ain Chock, Immunology and Biodiversity Laboratory, Hassan II University, Casablanca.,Department of Medicine, Research Center of Abulcasis University of Health Sciences, Rabat, Morocco.,Department of Biology, Faculty of Sciences, Mohammed V University in Rabat, Rabat, Morocco
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6
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Shiravand Y, Walter U, Jurk K. Fine-Tuning of Platelet Responses by Serine/Threonine Protein Kinases and Phosphatases-Just the Beginning. Hamostaseologie 2021; 41:206-216. [PMID: 34192779 DOI: 10.1055/a-1476-7873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Comprehensive proteomic analyses of human and murine platelets established an extraordinary intracellular repertoire of signaling components, which control crucial functions. The spectrum of platelet serine/threonine protein kinases (more than 100) includes the AGC family (protein kinase A, G, C [PKA, PKG, PKC]), the mitogen-activated protein kinases (MAPKs), and others. PKA and PKG have multiple significantly overlapping substrates in human platelets, which possibly affect functions with clear "signaling nodes" of regulation by multiple protein kinases/phosphatases. Signaling nodes are intracellular Ca2+ stores, the contractile system (myosin light chains), and other signaling components such as G-proteins, protein kinases, and protein phosphatases. An example for this fine-tuning is the tyrosine kinase Syk, a crucial component of platelet activation, which is controlled by several serine/threonine and tyrosine protein kinases as well as phosphatases. Other protein kinases including PKA/PKG modulate protein phosphatase 2A, which may be a master regulator of MAPK signaling in human platelets. Protein kinases and in particular MAPKs are targeted by an increasing number of clinically used inhibitors. However, the precise regulation and fine-tuning of these protein kinases and their effects on other signaling components in platelets are only superficially understood-just the beginning. However, promising future approaches are in sight.
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Affiliation(s)
- Yavar Shiravand
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | - Ulrich Walter
- Center for Thrombosis and Hemostasis (CTH), University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Kerstin Jurk
- Center for Thrombosis and Hemostasis (CTH), University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
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7
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Shevchuk O, Begonja AJ, Gambaryan S, Totzeck M, Rassaf T, Huber TB, Greinacher A, Renne T, Sickmann A. Proteomics: A Tool to Study Platelet Function. Int J Mol Sci 2021; 22:ijms22094776. [PMID: 33946341 PMCID: PMC8125008 DOI: 10.3390/ijms22094776] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 04/22/2021] [Accepted: 04/22/2021] [Indexed: 12/22/2022] Open
Abstract
Platelets are components of the blood that are highly reactive, and they quickly respond to multiple physiological and pathophysiological processes. In the last decade, it became clear that platelets are the key components of circulation, linking hemostasis, innate, and acquired immunity. Protein composition, localization, and activity are crucial for platelet function and regulation. The current state of mass spectrometry-based proteomics has tremendous potential to identify and quantify thousands of proteins from a minimal amount of material, unravel multiple post-translational modifications, and monitor platelet activity during drug treatments. This review focuses on the role of proteomics in understanding the molecular basics of the classical and newly emerging functions of platelets. including the recently described role of platelets in immunology and the development of COVID-19.The state-of-the-art proteomic technologies and their application in studying platelet biogenesis, signaling, and storage are described, and the potential of newly appeared trapped ion mobility spectrometry (TIMS) is highlighted. Additionally, implementing proteomic methods in platelet transfusion medicine, and as a diagnostic and prognostic tool, is discussed.
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Affiliation(s)
- Olga Shevchuk
- Leibniz-Institut für Analytische Wissenschaften—ISAS—e.V, Bunsen-Kirchhoff-Straße 11, 44139 Dortmund, Germany
- Department of Immunodynamics, Institute of Experimental Immunology and Imaging, University Hospital Essen, Hufelandstrasse 55, 45147 Essen, Germany
- Correspondence: (O.S.); (A.S.)
| | - Antonija Jurak Begonja
- Department of Biotechnology, University of Rijeka, Radmile Matejčić 2, 51000 Rijeka, Croatia;
| | - Stepan Gambaryan
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, Torez pr. 44, 194223 St. Petersburg, Russia;
| | - Matthias Totzeck
- West German Heart and Vascular Center, Department of Cardiology and Vascular Medicine, University Hospital Essen, Hufelandstrasse 55, 45147 Essen, Germany; (M.T.); (T.R.)
| | - Tienush Rassaf
- West German Heart and Vascular Center, Department of Cardiology and Vascular Medicine, University Hospital Essen, Hufelandstrasse 55, 45147 Essen, Germany; (M.T.); (T.R.)
| | - Tobias B. Huber
- III. Department of Medicine, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany;
| | - Andreas Greinacher
- Institut für Immunologie und Transfusionsmedizin, Universitätsmedizin Greifswald, Sauerbruchstraße, 17475 Greifswald, Germany;
| | - Thomas Renne
- Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany;
| | - Albert Sickmann
- Leibniz-Institut für Analytische Wissenschaften—ISAS—e.V, Bunsen-Kirchhoff-Straße 11, 44139 Dortmund, Germany
- Medizinisches Proteom-Center (MPC), Medizinische Fakultät, Ruhr-Universität Bochum, 44801 Bochum, Germany
- Department of Chemistry, College of Physical Sciences, University of Aberdeen, Aberdeen AB24 3FX, UK
- Correspondence: (O.S.); (A.S.)
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8
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Aliotta A, Bertaggia Calderara D, Zermatten MG, Alberio L. Sodium-Calcium Exchanger Reverse Mode Sustains Dichotomous Ion Fluxes Required for Procoagulant COAT Platelet Formation. Thromb Haemost 2020; 121:309-321. [PMID: 33099282 DOI: 10.1055/s-0040-171670] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Procoagulant collagen-and-thrombin (COAT)-activated platelets represent a subpopulation of activated platelets, which retain a coat of prohemostatic proteins and express phosphatidylserine on their surface. Dichotomous intracellular signaling generating procoagulant platelet activity instead of traditional aggregating endpoints is still not fully elucidated. It has been demonstrated that secondary messengers such as calcium and sodium play a critical role in platelet activation. Therefore, we developed a flow cytometric analysis to investigate intracellular ion fluxes simultaneously during generation of aggregating and procoagulant platelets. Human platelets were activated by convulxin-plus-thrombin. Cytosolic calcium, sodium, and potassium ion fluxes were visualized by specific ion probes and analyzed by flow cytometry. We observed high and prolonged intracellular calcium concentration, transient sodium increase, and fast potassium efflux in COAT platelets, whereas aggregating non-COAT platelets rapidly decreased their calcium content, maintaining higher cytosolic sodium, and experiencing lower and slower potassium depletion. Considering these antithetical patterns, we investigated the role of the sodium-calcium exchanger (NCX) during convulxin-plus-thrombin activation. NCX inhibitors, CBDMB and ORM-10103, dose-dependently reduced the global calcium mobilization induced by convulxin-plus-thrombin activation and dose-dependently prevented formation of procoagulant COAT platelets. Our data demonstrate that both NCX modes are used after convulxin-plus-thrombin-induced platelet activation. Non-COAT platelets use forward-mode NCX, thus pumping calcium out and moving sodium in, while COAT platelets rely on reverse NCX function, which pumps additional calcium into the cytosol, by extruding sodium. In conclusion, we described for the first time the critical and dichotomous role of NCX function during convulxin-plus-thrombin-induced platelet activation.
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Affiliation(s)
- Alessandro Aliotta
- Hemostasis and Platelet Research Laboratory, Division of Hematology and Central Hematology Laboratory, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland
| | - Debora Bertaggia Calderara
- Hemostasis and Platelet Research Laboratory, Division of Hematology and Central Hematology Laboratory, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland
| | - Maxime G Zermatten
- Hemostasis and Platelet Research Laboratory, Division of Hematology and Central Hematology Laboratory, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland
| | - Lorenzo Alberio
- Hemostasis and Platelet Research Laboratory, Division of Hematology and Central Hematology Laboratory, Lausanne University Hospital (CHUV) and University of Lausanne (UNIL), Lausanne, Switzerland
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9
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The Cell Cycle Checkpoint System MAST(L)-ENSA/ARPP19-PP2A is Targeted by cAMP/PKA and cGMP/PKG in Anucleate Human Platelets. Cells 2020; 9:cells9020472. [PMID: 32085646 PMCID: PMC7072724 DOI: 10.3390/cells9020472] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 02/14/2020] [Accepted: 02/14/2020] [Indexed: 12/13/2022] Open
Abstract
The cell cycle is controlled by microtubule-associated serine/threonine kinase-like (MASTL), which phosphorylates the cAMP-regulated phosphoproteins 19 (ARPP19) at S62 and 19e/α-endosulfine (ENSA) at S67and converts them into protein phosphatase 2A (PP2A) inhibitors. Based on initial proteomic data, we hypothesized that the MASTL-ENSA/ARPP19-PP2A pathway, unknown until now in platelets, is regulated and functional in these anucleate cells. We detected ENSA, ARPP19 and various PP2A subunits (including seven different PP2A B-subunits) in proteomic studies of human platelets. ENSA-S109/ARPP19–S104 were efficiently phosphorylated in platelets treated with cAMP- (iloprost) and cGMP-elevating (NO donors/riociguat) agents. ENSA-S67/ARPP19-S62 phosphorylations increased following PP2A inhibition by okadaic acid (OA) in intact and lysed platelets indicating the presence of MASTL or a related protein kinase in human platelets. These data were validated with recombinant ENSA/ARPP19 and phospho-mutants using recombinant MASTL, protein kinase A and G. Both ARPP19 phosphorylation sites S62/S104 were dephosphorylated by platelet PP2A, but only S62-phosphorylated ARPP19 acted as PP2A inhibitor. Low-dose OA treatment of platelets caused PP2A inhibition, diminished thrombin-stimulated platelet aggregation and increased phosphorylation of distinct sites of VASP, Akt, p38 and ERK1/2 MAP kinases. In summary, our data establish the entire MASTL(like)–ENSA/ARPP19–PP2A pathway in human platelets and important interactions with the PKA, MAPK and PI3K/Akt systems.
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10
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Fauré S, Van Agthoven A, Bernot D, Altié A, Grino M, Alessi MC, Malergue F, Canault M. A Novel Rapid Method of Red Blood Cell and Platelet Permeabilization and Staining for Flow Cytometry Analysis. CYTOMETRY PART B-CLINICAL CYTOMETRY 2019; 96:426-435. [PMID: 31301165 DOI: 10.1002/cyto.b.21839] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 06/17/2019] [Accepted: 06/24/2019] [Indexed: 01/01/2023]
Abstract
BACKGROUND Flow cytometry essentially focuses on surface-expressed proteins, with few protocols being devoted to intracellular components. We evaluated a two-step procedure using new formaldehyde-free permeabilization and staining reagents that allow the staining of platelets and red blood cells (RBCs) from whole blood. METHODS Citrated blood was treated with the new staining protocol (NSP) or control reagent (phosphate-buffered solution bovine serum albumin) and stained with antibodies against surface or intracellular markers. The effects of the NSP on cell integrity, morphology, and content were evaluated. RESULTS The NSP slightly reduced the cell count (~20%) and changed the RBC morphology with a 42% mean diameter reduction. Conversely, the NSP did not affect platelet discoid morphology and led to a minor size decrease (11%). These morphological changes neither impelled a gating strategy modification nor interfered with the discrimination among populations based on surface markers. The NSP provided intracellular access to all the tested antigens: CD62P, FXIII, and CD63 in platelets and glycated and fetal hemoglobin (HbA1c and HbF) and nucleic acid in RBCs. The NSP gave excellent intra-assay precision with minimal impact on cell morphology and fluorescence labelling over time (up to 24 h). CONCLUSIONS With the ability to detect surface and intracellular antigens through a rapid preparation protocol without washing steps or toxic formaldehyde treatment, this NSP designed for research offers a marked improvement in the analysis of platelets and RBCs isolated directly from whole blood. Consequently, the NSP opens new avenues to investigate platelet degranulation and erythrocyte subpopulations. © 2019 International Clinical Cytometry Society.
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Affiliation(s)
- Sixtine Fauré
- Aix-Marseille Univ, INSERM, INRA, C2VN, Marseille, France.,Beckman Coulter Life Sciences Immunotech, Marseille, France
| | | | - Denis Bernot
- Centre de référence sur les pathologies plaquettaires (CRPP), CHU Timone, Marseille, France
| | | | - Michel Grino
- Aix-Marseille Univ, INSERM, INRA, C2VN, Marseille, France
| | - Marie-Christine Alessi
- Aix-Marseille Univ, INSERM, INRA, C2VN, Marseille, France.,Centre de référence sur les pathologies plaquettaires (CRPP), CHU Timone, Marseille, France
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11
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Mitrugno A, Rigg RA, Laschober NB, Ngo AT, Pang J, Williams CD, Aslan JE, McCarty OJ. Potentiation of TRAP-6-induced platelet dense granule release by blockade of P2Y 12 signaling with MRS2395. Platelets 2018; 29:383-394. [PMID: 28523947 PMCID: PMC6155984 DOI: 10.1080/09537104.2017.1316482] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 03/06/2017] [Accepted: 03/24/2017] [Indexed: 12/30/2022]
Abstract
The release of ADP from platelet dense granules and its binding to platelet P2Y12 receptors is key to amplifying the initial hemostatic response and propagating thrombus formation. P2Y12 has thus emerged as a therapeutic target to safely and effectively prevent secondary thrombotic events in patients with acute coronary syndrome or a history of myocardial infarction. Pharmacological inhibition of P2Y12 receptors represents a useful approach to better understand the signaling mediated by these receptors and to elucidate the role of these receptors in a multitude of platelet hemostatic and thrombotic responses. The present work examined and compared the effects of four different P2Y12 inhibitors (MRS2395, ticagrelor, PSB 0739, and AR-C 66096) on platelet function in a series of in vitro studies of platelet dense granule secretion and trafficking, calcium generation, and protein phosphorylation. Our results show that in platelets activated with the PAR-1 agonist TRAP-6 (thrombin receptor-activating peptide), inhibition of P2Y12 with the antagonist MRS2395, but not ticagrelor, PSB 0739 or AR-C 66096, potentiated human platelet dense granule trafficking to the plasma membrane and release into the extracellular space, cytosolic Ca2+ influx, and phosphorylation of GSK3β-Ser9 through a PKC-dependent pathway. These results suggest that inhibition of P2Y12 with MRS2395 may act in concert with PAR-1 signaling and result in the aberrant release of ADP by platelet dense granules, thus reducing or counteracting the anticipated anti-platelet efficacy of this inhibitor.
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Affiliation(s)
- Annachiara Mitrugno
- Department of Biomedical Engineering,Oregon Health & Science University, Portland, OR, USA
- Cell, Developmental & Cancer Biology, Oregon Health & Science University, Portland, OR, USA
- Division of Hematology & Medical Oncology and Oregon Health & Science University, Portland, OR,
USA
| | - Rachel A. Rigg
- Department of Biomedical Engineering,Oregon Health & Science University, Portland, OR, USA
| | - Nicole B. Laschober
- Department of Biomedical Engineering,Oregon Health & Science University, Portland, OR, USA
| | - Anh T.P. Ngo
- Department of Biomedical Engineering,Oregon Health & Science University, Portland, OR, USA
| | - Jiaqing Pang
- Department of Biomedical Engineering,Oregon Health & Science University, Portland, OR, USA
| | | | - Joseph E. Aslan
- Knight Cardiovascular Institute, School of Medicine, Oregon Health & Science University, Portland, OR,
USA
| | - Owen J.T. McCarty
- Department of Biomedical Engineering,Oregon Health & Science University, Portland, OR, USA
- Cell, Developmental & Cancer Biology, Oregon Health & Science University, Portland, OR, USA
- Division of Hematology & Medical Oncology and Oregon Health & Science University, Portland, OR,
USA
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12
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Sánchez G, Estrada O, Acha G, Cardozo A, Peña F, Ruiz MC, Michelangeli F, Alvarado-Castillo C. The norpurpureine alkaloid from Annona purpurea inhibits human platelet activation in vitro. Cell Mol Biol Lett 2018; 23:15. [PMID: 29713353 PMCID: PMC5905151 DOI: 10.1186/s11658-018-0082-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 04/09/2018] [Indexed: 01/01/2023] Open
Abstract
Background The leaves of Annona purpurea have yielded several alkaloids with anti-aggregation activities against rabbit platelets. This is promising in the search for agents that might act against platelets and reduce the incidence of cardiovascular diseases. Since significant differences in platelet function have been reported between human and animal platelets, a study focusing on the effect of A. purpurea extracts against human platelet activation is necessary. Methods The compounds in an A. purpurea ethanolic extract underwent bio-guided fractionation and were used for in vitro human platelet aggregation assays to isolate the compounds with anti-platelet activity. The bioactive compounds were identified by spectroscopic analysis. Additional platelet studies were performed to characterize their action as inhibitors of human platelet activation. Results The benzylisoquinoline alkaloid norpurpureine was identified as the major anti-platelet compound. The IC50 for norpurpureine was 80 μM against platelets when stimulated with adenosine 5′-diphosphate (ADP), collagen and thrombin. It was pharmacologically effective from 20 to 220 μM. Norpurpureine (220 μM) exhibited its in vitro effectiveness in samples from 30 healthy human donors who did not take any drugs during the 2 weeks prior to the collection. Norpurpureine also gradually inhibited granule secretion and adhesion of activated platelets to immobilized fibrinogen. At the intra-platelet level, norpurpureine prevented agonist-stimulated calcium mobilization and cAMP reduction. Structure–activity relationship analysis indicates that the lack of a methyl group at the nitrogen seems to be key in the ability of the compound to interact with its molecular target. Conclusion Norpurpureine displays a promising in vitro pharmacological profile as an inhibitor of human platelet activation. Its molecular target could be a common effector between Ca2+ and cAMP signaling, such as the PLC-PKC-Ca2+ pathway and PDEs. This needs further evaluation at the protein isoform level. Electronic supplementary material The online version of this article (10.1186/s11658-018-0082-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Gabriela Sánchez
- 1Centro de Biofísica y Bioquímica (CBB), Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas, Bolivarian Republic of Venezuela
| | - Omar Estrada
- 1Centro de Biofísica y Bioquímica (CBB), Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas, Bolivarian Republic of Venezuela
| | - Giovana Acha
- 1Centro de Biofísica y Bioquímica (CBB), Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas, Bolivarian Republic of Venezuela
| | - Alfonso Cardozo
- 2Laboratorio de Botánica Sistemática, Facultad de Agronomía, Universidad Central de Venezuela (UCV), Maracay, Bolivarian Republic of Venezuela
| | - Franshelle Peña
- 1Centro de Biofísica y Bioquímica (CBB), Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas, Bolivarian Republic of Venezuela
| | - Marie Christine Ruiz
- 1Centro de Biofísica y Bioquímica (CBB), Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas, Bolivarian Republic of Venezuela
| | - Fabián Michelangeli
- 1Centro de Biofísica y Bioquímica (CBB), Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas, Bolivarian Republic of Venezuela
| | - Claudia Alvarado-Castillo
- 1Centro de Biofísica y Bioquímica (CBB), Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas, Bolivarian Republic of Venezuela.,3Laboratorio de Hemostasia y Genética Vascular, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas, Apartado 20632, K11 de la Carretera Panamericana, Caracas, 1020-A Bolivarian Republic of Venezuela
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13
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Stefanini L, Bergmeier W. Negative regulators of platelet activation and adhesion. J Thromb Haemost 2018; 16:220-230. [PMID: 29193689 PMCID: PMC5809258 DOI: 10.1111/jth.13910] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Indexed: 12/29/2022]
Abstract
Platelets are small anucleated cells that constantly patrol the cardiovascular system to preserve its integrity and prevent excessive blood loss where the vessel lining is breached. Their key challenge is to form a hemostatic plug under conditions of high shear forces. To do so, platelets have evolved a molecular machinery that enables them to sense trace amounts of signals at the site of damage and to rapidly shift from a non-adhesive to a pro-adhesive state. However, this highly efficient molecular machinery can also lead to unintended platelet activation and cause clinical complications such as thrombocytopenia and thrombosis. Thus, several checkpoints are in place to tightly control platelet activation and adhesiveness in space and time. In this review, we will discuss select negative regulators of platelet activation, which are critical to maintain patrolling platelets in a quiescent, non-adhesive state and/or to limit platelet adhesion to sites of injury.
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Affiliation(s)
- L Stefanini
- Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, Rome, Italy
| | - W Bergmeier
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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14
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Beck S, Leitges M, Stegner D. Protein kinase Cι/λ is dispensable for platelet function in thrombosis and hemostasis in mice. Cell Signal 2017; 38:223-229. [PMID: 28739484 DOI: 10.1016/j.cellsig.2017.07.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 07/05/2017] [Accepted: 07/20/2017] [Indexed: 11/17/2022]
Abstract
Platelet activation at sites of vascular injury is crucial for hemostasis, but it may also cause myocardial infarction or ischemic stroke. Upon platelet activation, cytoskeletal reorganization is essential for platelet secretion and thrombus formation. Members of the protein kinase C family, which includes 12 isoforms, are involved in most platelet responses required for thrombus formation. The atypical protein kinase Cι/λ (PKCι/λ) has been implicated as an important mediator of cell polarity, carcinogenesis and immune cell responses. PKCι/λ is known to be associated with the small GTPase Cdc42, an important mediator of multiple platelet functions; however, its exact function in platelets is not known. To study the role of PKCι/λ, we generated platelet- and megakaryocyte-specific PKCι/λ knockout mice (Prkcifl/fl, Pf4-Cre) and used them to investigate the function of PKCι/λ in platelet activation and aggregation in vitro and in vivo. Surprisingly, lack of PKCι/λ had no detectable effect on platelet spreading and function in vitro and in vivo under all tested conditions. These results indicate that PKCι/λ is dispensable for Cdc42-triggered processes and for thrombosis and hemostasis in mice.
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Affiliation(s)
- Sarah Beck
- Institute of Experimental Biomedicine, University Hospital and Rudolf Virchow Center, University of Würzburg, Würzburg, Germany
| | | | - David Stegner
- Institute of Experimental Biomedicine, University Hospital and Rudolf Virchow Center, University of Würzburg, Würzburg, Germany.
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15
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DioxolaneA3-phosphatidylethanolamines are generated by human platelets and stimulate neutrophil integrin expression. Redox Biol 2017; 11:663-672. [PMID: 28160743 PMCID: PMC5288459 DOI: 10.1016/j.redox.2017.01.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Accepted: 01/03/2017] [Indexed: 11/23/2022] Open
Abstract
Activated platelets generate an eicosanoid proposed to be 8-hydroxy-9,10-dioxolane A3 (DXA3). Herein, we demonstrate that significant amounts of DXA3 are rapidly attached to phosphatidylethanolamine (PE) forming four esterified eicosanoids, 16:0p, 18:0p, 18:1p and 18:0a/DXA3-PEs that can activate neutrophil integrin expression. These lipids comprise the majority of DXA3 generated by platelets, are formed in ng amounts (24.3±6.1ng/2×108) and remain membrane bound. Pharmacological studies revealed DXA3-PE formation involves cyclooxygenase-1 (COX), protease-activated receptors (PAR) 1 and 4, cytosolic phospholipase A2 (cPLA2), phospholipase C and intracellular calcium. They are generated primarily via esterification of newly formed DXA3, but can also be formed in vitro via co-oxidation of PE during COX-1 co-oxidation of arachidonate. All four DXA3-PEs were detected in human clots. Purified platelet DXA3-PE activated neutrophil Mac-1 expression, independently of its hydrolysis to the free eicosanoid. This study demonstrates the structures and cellular synthetic pathway for a family of leukocyte-activating platelet phospholipids generated on acute activation, adding to the growing evidence that enzymatic PE oxidation is a physiological event in innate immune cells.
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16
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Distinctive roles of PKC delta isozyme in platelet function. Curr Res Transl Med 2016; 64:135-139. [PMID: 27765273 DOI: 10.1016/j.retram.2016.05.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2016] [Revised: 05/15/2016] [Accepted: 05/20/2016] [Indexed: 12/15/2022]
Abstract
Platelet activation is a complex balance of positive and negative signaling pathways. Several protein kinase C (PKC) isoforms are expressed in human platelets. They are a major regulator of platelet granule secretion, activation and aggregation activity. One of those isoforms is the PKCδ isozyme, it has a central yet complex role in platelets such as opposite signaling functions depending on the nature of the agonist, it concentration and pathway. In fact, it has been shown that PKCδ has an overall negative influence on platelet function in response to collagen, while, following PAR stimulation, PKCδ has a positive effect on platelet function. Understanding the crucial role of PKCδ in platelet functions is recently emerging in the literature, therefore, further investigations should shed light into its specific role in hemostasis. In this review, we focus on the different roles of PKCδ in platelet activation, aggregation and thrombus formation.
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17
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Bhavanasi D, Badolia R, Manne BK, Janapati S, Dangelmaier CT, Mazharian A, Jin J, Kim S, Zhang X, Chen X, Senis YA, Kunapuli SP. Cross talk between serine/threonine and tyrosine kinases regulates ADP-induced thromboxane generation in platelets. Thromb Haemost 2015; 114:558-68. [PMID: 25947062 DOI: 10.1160/th14-09-0775] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 03/26/2015] [Indexed: 11/05/2022]
Abstract
ADP-induced thromboxane generation depends on Src family kinases (SFKs) and is enhanced with pan-protein kinase C (PKC) inhibitors, but it is not clear how these two events are linked. The aim of the current study is to investigate the role of Y311 phosphorylated PKCδ in regulating ADP-induced platelet activation. In the current study, we employed various inhibitors and murine platelets from mice deficient in specific molecules to evaluate the role of PKCδ in ADP-induced platelet responses. We show that, upon stimulation of platelets with 2MeSADP, Y311 on PKCδ is phosphorylated in a P2Y1/Gq and Lyn-dependent manner. By using PKCδ and Lyn knockout murine platelets, we also show that tyrosine phosphorylated PKCδ plays a functional role in mediating 2MeSADP-induced thromboxane generation. 2MeSADP-induced PKCδ Y311 phosphorylation and thromboxane generation were potentiated in human platelets pre-treated with either a pan-PKC inhibitor, GF109203X or a PKC α/β inhibitor and in PKC α or β knockout murine platelets compared to controls. Furthermore, we show that PKC α/β inhibition potentiates the activity of SFK, which further hyper-phosphorylates PKCδ and potentiates thromboxane generation. These results show for the first time that tyrosine phosphorylated PKCδ regulates ADP-induced thromboxane generation independent of its catalytic activity and that classical PKC isoforms α/β regulate the tyrosine phosphorylation on PKCδ and subsequent thromboxane generation through tyrosine kinase, Lyn, in platelets.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | - Satya P Kunapuli
- Satya P. Kunapuli PhD, Department of Physiology and Sol Sherry Thrombosis Center,, Temple University School of Medicine,, 3420 North Broad street, MRB 414, Philadelphia PA, 19140, USA, Tel.: +1 215 707 4615, Fax: +1 215 707 6944, E-mail:
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18
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Burkhart JM, Gambaryan S, Watson SP, Jurk K, Walter U, Sickmann A, Heemskerk JWM, Zahedi RP. What can proteomics tell us about platelets? Circ Res 2014; 114:1204-19. [PMID: 24677239 DOI: 10.1161/circresaha.114.301598] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
More than 130 years ago, it was recognized that platelets are key mediators of hemostasis. Nowadays, it is established that platelets participate in additional physiological processes and contribute to the genesis and progression of cardiovascular diseases. Recent data indicate that the platelet proteome, defined as the complete set of expressed proteins, comprises >5000 proteins and is highly similar between different healthy individuals. Owing to their anucleate nature, platelets have limited protein synthesis. By implication, in patients experiencing platelet disorders, platelet (dys)function is almost completely attributable to alterations in protein expression and dynamic differences in post-translational modifications. Modern platelet proteomics approaches can reveal (1) quantitative changes in the abundance of thousands of proteins, (2) post-translational modifications, (3) protein-protein interactions, and (4) protein localization, while requiring only small blood donations in the range of a few milliliters. Consequently, platelet proteomics will represent an invaluable tool for characterizing the fundamental processes that affect platelet homeostasis and thus determine the roles of platelets in health and disease. In this article we provide a critical overview on the achievements, the current possibilities, and the future perspectives of platelet proteomics to study patients experiencing cardiovascular, inflammatory, and bleeding disorders.
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Affiliation(s)
- Julia M Burkhart
- From the Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., Dortmund, Germany (J.M.B., A.S., R.P.Z); Institut für Klinische Biochemie und Pathobiochemie, Universitätsklinikum Würzburg, Würzburg, Germany (S.G.); Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia (S.G.); Centre for Cardiovascular Sciences, Institute for Biomedical Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom (S.P.W.); Center for Thrombosis and Hemostasis, Universitätsklinikum der Johannes Gutenberg-Universität Mainz, Mainz, Germany (K.J., U.W.); Medizinisches Proteom Center, Ruhr Universität Bochum, Bochum, Germany (A.S.); Department of Chemistry, College of Physical Sciences, University of Aberdeen, Aberdeen, Scotland, United Kingdom (A.S.); and Department of Biochemistry, CARIM, Maastricht University, Maastricht, The Netherlands (J.W.M.H.)
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19
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Calcium-dependent PKC isoforms have specialized roles in short-term synaptic plasticity. Neuron 2014; 82:859-71. [PMID: 24794094 DOI: 10.1016/j.neuron.2014.04.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/26/2014] [Indexed: 01/04/2023]
Abstract
Posttetanic potentiation (PTP) is a widely observed form of short-term plasticity lasting for tens of seconds after high-frequency stimulation. Here we show that although protein kinase C (PKC) mediates PTP at the calyx of Held synapse in the auditory brainstem before and after hearing onset, PTP is produced primarily by an increased probability of release (p) before hearing onset, and by an increased readily releasable pool of vesicles (RRP) thereafter. We find that these mechanistic differences, which have distinct functional consequences, reflect unexpected differential actions of closely related calcium-dependent PKC isoforms. Prior to hearing onset, when PKCγ and PKCβ are both present, PKCγ mediates PTP by increasing p and partially suppressing PKCβ actions. After hearing onset, PKCγ is absent and PKCβ produces PTP by increasing RRP. In hearing animals, virally expressed PKCγ overrides PKCβ to produce PTP by increasing p. Thus, two similar PKC isoforms mediate PTP in distinctly different ways.
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20
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de Witt SM, Verdoold R, Cosemans JM, Heemskerk JW. Insights into platelet-based control of coagulation. Thromb Res 2014; 133 Suppl 2:S139-48. [DOI: 10.1016/s0049-3848(14)50024-2] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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21
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Bhavanasi D, Kostyak JC, Swindle J, Kilpatrick LE, Kunapuli SP. CGX1037 is a novel PKC isoform delta selective inhibitor in platelets. Platelets 2014; 26:2-9. [PMID: 24433221 DOI: 10.3109/09537104.2013.868877] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Platelets upon activation change their shape, aggregate and secrete alpha and dense granule contents among which ADP acts as a feedback activator. Different Protein Kinase C (PKC) isoforms have specific non-redundant roles in mediating platelet responses including secretion and thrombus formation. Murine platelets lacking specific PKC isoforms have been used to evaluate the isoform specific functions. Novel PKC isoform δ has been shown to play an important role in some pathological processes. Lack of specific inhibitors for PKCδ has restricted analysis of its role in various cells. The current study was carried out to evaluate a novel small molecule PKCδ inhibitor, CGX1037 in platelets. Platelet aggregation, dense granule secretion and western blotting experiments were performed to evaluate CGX1037. In human platelets, CGX1037 inhibited PAR4-mediated phosphorylation on PKD2, a PKCδ-specific substrate. Pre-treatment of human or murine platelets with CGX1037 inhibited PAR4-mediated dense granule secretion whereas it potentiated GPVI-mediated dense granule secretion similar to the responses observed in murine platelets lacking PKCδ· Furthermore, pre-treatment of platelets from PKCδ(-/-) mice with CGX1037 had no significant additive effect on platelet responses suggesting the specificity of CGX1037. Hence, we show that CGX1037 is a selective small molecule inhibitor of PKCδ in platelets.
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Affiliation(s)
- Dheeraj Bhavanasi
- Department of Physiology, Temple University School of Medicine , Philadelphia, PA , USA
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23
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Abstract
Hemostasis encompasses the tightly regulated processes of blood clotting, platelet activation, and vascular repair. After wounding, the hemostatic system engages a plethora of vascular and extravascular receptors that act in concert with blood components to seal off the damage inflicted to the vasculature and the surrounding tissue. The first important component that contributes to hemostasis is the coagulation system, while the second important component starts with platelet activation, which not only contributes to the hemostatic plug, but also accelerates the coagulation system. Eventually, coagulation and platelet activation are switched off by blood-borne inhibitors and proteolytic feedback loops. This review summarizes new concepts of activation of proteases that regulate coagulation and anticoagulation, to give rise to transient thrombin generation and fibrin clot formation. It further speculates on the (patho)physiological roles of intra- and extravascular receptors that operate in response to these proteases. Furthermore, this review provides a new framework for understanding how signaling and adhesive interactions between endothelial cells, leukocytes, and platelets can regulate thrombus formation and modulate the coagulation process. Now that the key molecular players of coagulation and platelet activation have become clear, and their complex interactions with the vessel wall have been mapped out, we can also better speculate on the causes of thrombosis-related angiopathies.
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Affiliation(s)
- Henri H. Versteeg
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands; Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands; and Department of Medicine, Academic Medical Center, Amsterdam, The Netherlands
| | - Johan W. M. Heemskerk
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands; Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands; and Department of Medicine, Academic Medical Center, Amsterdam, The Netherlands
| | - Marcel Levi
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands; Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands; and Department of Medicine, Academic Medical Center, Amsterdam, The Netherlands
| | - Pieter H. Reitsma
- Einthoven Laboratory for Experimental Vascular Medicine, Leiden University Medical Center, Leiden, The Netherlands; Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands; and Department of Medicine, Academic Medical Center, Amsterdam, The Netherlands
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Goggs R, Poole AW. Platelet signaling-a primer. J Vet Emerg Crit Care (San Antonio) 2012; 22:5-29. [PMID: 22316389 DOI: 10.1111/j.1476-4431.2011.00704.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Accepted: 11/25/2011] [Indexed: 12/28/2022]
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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25
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Protein kinase C-theta in platelet activation. FEBS Lett 2011; 585:3208-15. [DOI: 10.1016/j.febslet.2011.09.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 08/20/2011] [Accepted: 09/12/2011] [Indexed: 02/05/2023]
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