Aspirin modulates generation of procoagulant phospholipids in cardiovascular disease, by regulating LPCAT3

Enzymatically oxygenated phospholipids (eoxPL) from lipoxygenases (LOX) or cyclooxygenase (COX) are prothrombotic. Their generation in arterial disease, and their modulation by cardiovascular therapies is unknown. Furthermore, the Lands cycle acyl-transferases that catalyze their formation are unidentified. eoxPL were measured in platelets and leukocytes from an atherosclerotic cardiovascular disease (ASCVD) cohort and retrieved human arterial thrombi from three anatomical sites. The impact of age, gender, and aspirin was characterized in platelets from healthy subjects administered low-dose aspirin. The role of lysophosphatidylcholine acyltransferase 3 (LPCAT3) in eoxPL biosynthesis was tested using an inhibitor and a cell-free assay. Platelets from ASCVD patients generated lower levels of COX-derived eoxPL but elevated 12-LOX-diacyl forms, than platelets from healthy controls. This associated with aspirin and was recapitulated in healthy subjects by aspirin supplementation. P2Y12 inhibition had no impact on eoxPL. LPCAT3 inhibition selectively prevented 12-LOX-derived diacyl-eoxPL generation. LPCAT3 activity was not directly altered by aspirin. P2Y12 inhibition or aspirin had little impact on eoxPL in leukocytes. Complex aspirin-dependent gender and seasonal effects on platelet eoxPL generation were seen in healthy subjects. Limb or coronary (ST-elevation myocardial infarction, STEMI) thrombi displayed a platelet eoxPL signature while carotid thrombi had a white cell profile. EoxPL are altered in ASCVD by a commonly used cardiovascular therapy, and LPCAT3 was identified as the acyltransferase generating aspirin-sensitive 12-LOX diacyl forms. These changes to the phospholipid composition of blood cells in humans at risk of thrombosis may be clinically significant where the procoagulant membrane plays a central role in driving elevated thrombotic risk.