Bleeding diathesis in mice lacking JAK2 in platelets
| Autor: | Nathan Eaton, Saravanan Subramaniam, Sandra L. Haberichter, David Jakab, Hervé Falet, Caleb Drew, Marie L. Schulte, Hartmut Weiler |
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| Rok vydání: | 2020 |
| Předmět: |
0301 basic medicine
Blood Platelets Immunology Integrin Hemorrhage Platelet Membrane Glycoproteins 030204 cardiovascular system & hematology Biochemistry Collagen receptor Thrombosis and Hemostasis 03 medical and health sciences chemistry.chemical_compound Mice 0302 clinical medicine hemic and lymphatic diseases Medicine Animals Platelet Hemostatic function Mice Knockout Thrombocytosis Hemostasis biology business.industry food and beverages Tyrosine phosphorylation Cell Biology Hematology Janus Kinase 2 Platelet Activation 030104 developmental biology chemistry Cancer research biology.protein Disease Susceptibility GPVI business Tyrosine kinase hormones hormone substitutes and hormone antagonists |
| Zdroj: | Blood Adv |
| ISSN: | 2473-9537 |
| Popis: | The tyrosine kinase JAK2 is a critical component of intracellular JAK/STAT cytokine signaling cascades that is prevalent in hematopoietic cells such as hematopoietic stem and progenitor cells (HSPCs), megakaryocytes (MKs), and platelets. Individuals expressing somatic activating JAK2 mutations such as JAK2V617F commonly develop myeloproliferative neoplasms (MPNs) associated with serious complications, including venous and arterial thrombosis, a leading cause of mortality. Here, we investigated the role of JAK2 in hemostasis and thrombosis using Jak2fl/flPf4-Cre (Jak2Plt-/-) mice specifically lacking JAK2 within the platelet lineage. Jak2Plt-/- mice developed severe thrombocytosis with a 5-fold increase in circulating platelet number, MK hyperplasia, and splenomegaly. Jak2Plt-/-platelets were of normal size and the expression of major membrane surface glycoproteins was indistinguishable from controls, except for the integrin β3, which was reduced by 20%. Despite the thrombocytosis, Jak2Plt-/- mice had a severe bleeding diathesis, as evidenced by: 1) prolonged tail bleeding time; 2) failure to occlude in a ferric chloride-induced carotid artery injury model; and 3) failure to form stable thrombi in a laser-induced cremaster muscle injury model. Jak2Plt-/- platelets spread poorly on immobilized collagen or on immobilized fibrinogen following GPVI stimulation with the collagen-related peptide (CRP). Jak2Plt-/- platelets had defective α-granule secretion and integrin αIIbβ3 activation following stimulation with CRP, but not thrombin, and showed aggregation defects with low-doses of CRP. Together, the data support a GPVI-specific impairment in platelets lacking JAK2, a notion that was supported by impaired intracellular signaling following GPVI stimulation, as assessed by protein tyrosine phosphorylation. Jak2Plt-/- platelets adhered poorly to type I collagen under arterial shear rates in whole blood. However, JAK2 deletion in platelets did not alter plasma von Willebrand factor (VWF) levels or botrocetin-mediated binding of plasma VWF to GPIbα. Together, the results underline a critical role for JAK2 in platelet GPVI signaling and hemostatic function, which likely contributes to venous and arterial thrombosis observed in patients with MPNs with the activating JAK2V617F mutation. Disclosures No relevant conflicts of interest to declare. |
| Databáze: | OpenAIRE |
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