title: P2X7 receptor signaling contributes to tissue factor-dependent thrombosis in mice.
abstract: Thrombosis is initiated by tissue factor (TF), a coagulation cofactor/receptor expressed in the vessel wall, on myeloid cells, and on microparticles (MPs) with variable procoagulant activity. However, the molecular pathways that generate prothrombotic TF in vivo are poorly defined. The oxidoreductase protein disulfide isomerase (PDI) is thought to be involved in the activation of TF. Here, we found that in mouse myeloid cells, ATP-triggered signaling through purinergic receptor P2X, ligand-gated ion channel, 7 (P2X7 receptor; encoded by P2rx7) induced activation (decryption) of TF procoagulant activity and promoted release of TF+ MPs from macrophages and SMCs. The generation of prothrombotic MPs required P2X7 receptor-dependent production of ROS leading to increased availability of solvent-accessible extracellular thiols. An antibody to PDI with antithrombotic activity in vivo attenuated the release of procoagulant MPs. In addition, P2rx7-/- mice were protected from TF-dependent FeCl3-induced carotid artery thrombosis. BM chimeras revealed that P2X7 receptor prothrombotic function was present in both hematopoietic and vessel wall compartments. In contrast, an alternative anti-PDI antibody showed activities consistent with cellular activation typically induced by P2X7 receptor signaling. This anti-PDI antibody restored TF-dependent thrombosis in P2rx7-/- mice. These data suggest that PDI regulates a critical P2X7 receptor-dependent signaling pathway that generates prothrombotic TF, defining a link between inflammation and thrombosis with potential implications for antithrombotic therapy.
authors.affiliation: Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California 92037, USA.
authors.forename: Christian
authors.initials: C
authors.lastname: Furlan-Freguia
authors.forename: Patrizia
authors.initials: P
authors.lastname: Marchese
authors.forename: András
authors.initials: A
authors.lastname: Gruber
authors.forename: Zaverio M
authors.initials: ZM
authors.lastname: Ruggeri
authors.forename: Wolfram
authors.initials: W
authors.lastname: Ruf
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D016026:Bone Marrow Transplantation; D055252:Cell-Derived Microparticles / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000378:metabolism; D007249:Inflammation / Q000378:metabolism; D008264:Macrophages / Q000166:cytology / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D022423:Myeloid Cells / Q000166:cytology / Q000378:metabolism; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000378:metabolism; D019704:Protein Disulfide-Isomerases / Q000235:genetics / Q000378:metabolism; D058486:Receptors, Purinergic P2X7 / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D013925:Thromboplastin / Q000378:metabolism*; D013927:Thrombosis / Q000503:physiopathology*
chemical_list: D004791:Enzyme Inhibitors; D058486:Receptors, Purinergic P2X7; D000255:Adenosine Triphosphate; D013925:Thromboplastin; D019255:NADPH Oxidases; D019704:Protein Disulfide-Isomerases