title: Autocrine amplification of integrin αIIbβ3 activation and platelet adhesive responses by deoxyribose-1-phosphate.
abstract: Using direct injection mass spectrometry (DIMS) we discovered that deoxyribose-1-phosphate (dRP) is released by platelets upon activation. Interestingly, the addition of exogenous dRP to human platelets significantly increased platelet aggregation and integrin αIIbβ3 activation in response to thrombin. In parallel, genetically modified platelets with double genetic deletion of thymidine phosphorylase and uridine phosphorylase were characterised by reduced release of dRP, impaired aggregation and decreased integrin αIIbβ3 activation in response to thrombin. In vitro platelet adhesion onto fibrinogen and collagen under physiological flow conditions was potentiated by treatment of human platelets with exogenous dRP and impaired in transgenic platelets with reduced dRP release. Human and mouse platelets responded to dRP treatment with a sizeable increase in reactive oxygen species (ROS) generation and the pre-treament with the antioxidant apocynin abolished the effect of dRP on aggregation and integrin activation. Experiments directly assessing the activation of the small G protein Rap1b and protein kinase C suggested that dRP increases the basal levels of activity of these two pivotal platelet-activating pathways in a redox-dependent manner. Taken together, we present evidence that dRP is a novel autocrine amplifier of platelet activity, which acts on platelet redox levels and modulates integrin αIIbβ3.
authors.affiliation: Department of Pharmacy and Pharmacology, University of Bath, Claverton Campus, BA2 7AY, Bath, UK. G.Pula@bath.ac.uk
authors.forename: Dina S
authors.initials: DS
authors.lastname: Vara
authors.forename: Michelangelo
authors.initials: M
authors.lastname: Campanella
authors.forename: Ilaria
authors.initials: I
authors.lastname: Canobbio
authors.forename: Warwick B
authors.initials: WB
authors.lastname: Dunn
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Pizzorno
authors.forename: Michio
authors.initials: M
authors.lastname: Hirano
authors.forename: Giordano
authors.initials: G
authors.lastname: Pula
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D013058:Mass Spectrometry; D051379:Mice; D008810:Mice, Inbred C57BL; D010084:Oxidation-Reduction; D015539:Platelet Activation / Q000187:drug effects*; D010973:Platelet Adhesiveness; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism; D017382:Reactive Oxygen Species; D012267:Ribosemonophosphates / Q000737:chemistry*; D015398:Signal Transduction; D013917:Thrombin / Q000378:metabolism; D013939:Thymidine Phosphorylase / Q000378:metabolism; D014543:Uridine Phosphorylase / Q000378:metabolism; D020668:rap GTP-Binding Proteins / Q000378:metabolism
chemical_list: D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D017382:Reactive Oxygen Species; D012267:Ribosemonophosphates; C031302:2-deoxyribose 1-phosphate; D014543:Uridine Phosphorylase; D013939:Thymidine Phosphorylase; D011493:Protein Kinase C; D013917:Thrombin; C116753:RAP1B protein, human; D020668:rap GTP-Binding Proteins