Exposure of platelets to shear stress leads to aggregation in the absence of exogenous agonists. We

P-selectin is an integral membrane glycoprotein stored in the secretory granules of platelets and endothelial cells. To determine whether soluble P-selectin may be present in the circulation of healthy humans, we used a sandwich immunoassay to assess citrated plasma from 50 subjects. P-selectin was present in concentrations ranging from 19 to 521 ng/ml (mean +/- SD = 121 +/- 84 ng/ml). The apparent molecular weight of P-selectin immunoisolated from platelet-poor plasma was similar to that of the detergent-soluble form isolated from platelet membrane. Plasma levels of P-selectin were unaffected by the following procedures: (1) drawing of blood in the presence of protease inhibitors; (2) stimulation of platelet-rich plasma with aggregating agents; (3) ultracentrifugation at 100,000 g for 120 min at 4 degrees C or filtration through a 0.22 micron membrane; or (4) preincubation of platelet-poor plasma with immobilized anti-platelet glycoprotein Ib monoclonal antibodies. It appeared that plasma P-selectin did not result from the in vitro activation of platelets, nor was it derived from platelet microparticles. We also found that plasma P-selectin levels were significantly elevated in patients with thrombotic thrombocytopenic purpura (12 patients, 332 +/- 184 ng/ml, P < 0.001) and haemolytic uraemic syndrome (17 patients, 297 +/- 191 ng/ml, P < 0.0001), as compared to the normal levels. Thus, these data should facilitate the study of the pathophysiological significance of circulating P-selectin.

and Technology (PRESTO) (to M.A.), and Ono Pharmaceutical Company. AbstractBackground: Eosinophils are multifunctional granulocytes capable of releasing various cytokines, chemokines, and lipid mediators. We previously reported dysregulated fatty acid metabolism in peripheral blood-derived eosinophils from patients with severe asthma. However, functional characteristics of eosinophils present in allergic inflammatory tissues remain largely uncharacterized. Methods:We established a method for isolating CD69 hi CCR3 low CXCR4siglec-8 int eosinophils from nasal polyps of patients with eosinophilic rhinosinusitis (NP-EOS).Multi-omics analysis including lipidomics, proteomics, and transcriptomics was performed to analyze NP-EOS as compared to peripheral blood-derived eosinophils from healthy subjects (PB-EOS). Results: Lipidomic analysis revealed impaired synthesis of prostaglandins and 15lipoxygenase (15-LOX)-derived mediators, and selective upregulation of leukotriene D 4 production. Furthermore, proteomics and transcriptomics revealed changes in the expression of specific enzymes (GGT5, DPEP2, and 15-LOX) responsible for dysregulated lipid metabolism. Ingenuity pathway analysis indicated the importance of type 2 cytokines and pattern recognition receptor pathways. Stimulation of PB-EOS with eosinophil activators IL-5, GM-CSF, and agonists of TLR2 and NOD2 mimicked the observed changes in lipid metabolism.Conclusion: Inflammatory tissue-derived eosinophils possess a specific phenotype with dysregulated fatty acid metabolism that may be targeted therapeutically to control eosinophilic inflammatory diseases. K E Y W O R D Schronic rhinosinusitis, GGT5, human eosinophil, lipid mediator, multi-omics

No abstract