20-HETE induced platelet activation via a GPR75-independent pathway

Arachidonic acid (AA) metabolism is a critical regulator of platelet activation. The cytochrome P450 (CYP450) pathway represents a key metabolic route for AA, yet the precise roles of CYP450 enzymes and their primary product, 20-hydroxyeicosatetraenoic acid (20-HETE), in platelet activation and thrombosis remain incompletely elucidated.

We assessed the impact of aspirin on AA-induced platelet aggregation in human platelets. We further explored the influence of 20-HETE on platelet aggregation, granule secretion, and integrin activation. To elucidate the underlying mechanisms of 20-HETE action, we employed the antagonist 20-hydroxyeicosa-6(Z),15(Z)-dienoic acid (20-HEDE) and G protein-coupled receptor 75 (GPR75) knockout mice. Additionally, we evaluated the antiplatelet potential of the CYP450 inhibitor 17-octadecynoic acid (17-ODYA).

Aspirin suppressed platelet aggregation induced by low dose of AA and has no effect on high dose AA-induced aggregation.20-HETE indirectly induced platelet aggregation, granule release, and integrin αIIbβ3 activation in a concentration-dependent manner, independent of GPR75. The effects of 20-HETE were mediated through Gαq-coupled GPCRs. The CYP450 inhibitor 17-ODYA potently suppressed platelet activation and thrombus formation.

Thromboxane A2 (TXA2) is not indispensable for AA induced platelet activation. Moreover, 20-HETE has been identified as a potent platelet activator that acts through Gαq-coupled GPCRs. Its effects are mediated by downstream metabolites rather than direct interaction with GPR75.