DioxolaneA3-phosphatidylethanolamines are generated by human platelets and stimulate neutrophil integrin expression

Activated platelets generate an eicosanoid proposed to be 8-hydroxy-9,10-dioxolane A3 (DXA(3)). Herein, we demonstrate that significant amounts of DXA(3) are rapidly attached to phosphatidylethanolamine (PE) forming four esterified eicosanoids, 16:0p, 18:0p, 18:1p and 18:0a/DXA(3)-PEs that can activate neutrophil integrin expression. These lipids comprise the majority of DXA(3) generated by platelets, are formed in ng amounts (24.3±6.1 ng/2×10(8)) and remain membrane bound. Pharmacological studies revealed DXA(3)-PE formation involves cyclooxygenase-1 (COX), protease-activated receptors (PAR) 1 and 4, cytosolic phospholipase A(2) (cPLA(2)), phospholipase C and intracellular calcium. They are generated primarily via esterification of newly formed DXA(3,) but can also be formed in vitro via co-oxidation of PE during COX-1 co-oxidation of arachidonate. All four DXA(3)-PEs were detected in human clots. Purified platelet DXA(3)-PE activated neutrophil Mac-1 expression, independently of its hydrolysis to the free eicosanoid. This study demonstrates the structures and cellular synthetic pathway for a family of leukocyte-activating platelet phospholipids generated on acute activation, adding to the growing evidence that enzymatic PE oxidation is a physiological event in innate immune cells.