Overexpression of the platelet P2X1 ion channel in transgenic mice generates a novel prothrombotic phenotype
| Autor: | Arnaud Bonnefoy, Jos Vermylen, Marion A.H. Feijge, Ingrid Vreys, Emese Toth-Zsamboki, Rita Vos, Marijke J.E. Kuijpers, Sophie Danloy, Marc Hoylaerts, Cécile Oury, Johan W. M. Heemskerk |
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| Rok vydání: | 2003 |
| Předmět: |
Blood Platelets
Genetically modified mouse medicine.medical_specialty Transgene Immunology Mice Transgenic Biology Biochemistry Ion Channels Mice chemistry.chemical_compound Thromboxane A2 Thrombin Internal medicine medicine Animals Humans Platelet Cell Size Platelet Count Receptors Purinergic P2 Thrombosis Convulxin Cell Biology Hematology Blood Cell Count Adenosine Diphosphate Kinetics Adenosine diphosphate Phenotype Endocrinology chemistry Receptors Purinergic P2X Hemostasis Erythrocyte Count Megakaryocytes medicine.drug |
| Zdroj: | Blood. 101:3969-3976 |
| ISSN: | 1528-0020 0006-4971 |
| DOI: | 10.1182/blood-2002-10-3215 |
| Popis: | We have generated transgenic mice overexpressing the human P2X1 ion channel in the megakaryocytic cell lineage. Platelets from transgenic mice exhibited a gain of P2X1ionotropic activity as determined by more prominent P2X1-mediated Ca2+ influx and platelet shape change. P2X1 overexpression enhanced platelet secretion and aggregation evoked by low doses of collagen, convulxin, or the thromboxane A2 mimetic U46619. In contrast, transgenic platelet responses to adenosine diphosphate (ADP) or thrombin were normal. Perfusing whole blood from transgenic mice over collagen fibers at a shear rate of 1000 seconds−1 resulted in increased P2X1-dependent aggregate formation and phosphatidylserine exposure. Platelet hyperreactivity to collagen was correlated with up-regulated extracellular signal-regulated kinase 2 (ERK2) phosphorylation. Accordingly, the MEK1/2 inhibitor U0126 potently inhibited the collagen-induced aggregation of transgenic platelets when stirred or when perfused over a collagen surface. In a viscometer, shear stress caused potent aggregation of transgenic platelets under conditions in which wild-type platelets did not aggregate. In an in vivo model of thromboembolism consisting of intravenous injection of a low dose of collagen plus epinephrine, transgenic mice died more readily than wild-type mice. Preinjection of U0126 not only fully protected transgenic mice against thrombosis, it also enhanced the survival of wild-type mice injected with a higher collagen dose. Hence, the platelet P2X1 ion channel plays a role in hemostasis and thrombosis through its participation in collagen-, thromboxane A2-, and shear stress–triggered platelet responses. Activation of the ERK2 pathway is instrumental in these processes. |
| Databáze: | OpenAIRE |
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