Genistein preferentially inhibits collagen-induced platelet aggregation by suppressing granule secretion involving PI3K/Akt signaling in human platelets

Aberrant platelet activation plays a critical role in thrombosis and vascular occlusion associated with cardiovascular disease. Collagen exposed at sites of vascular injury is a major trigger of platelet activation through glycoprotein VI (GPVI)-dependent tyrosine kinase signaling pathways. Although genistein has been reported to exert antiplatelet effects, its agonist-dependent effects and the underlying molecular mechanisms remain incompletely understood. Therefore, this study aimed to investigate the inhibitory effects of genistein on platelet activation induced by different agonists and to elucidate the associated intracellular signaling pathways. Genistein preferentially inhibited collagen-induced platelet aggregation in human platelets, whereas thrombin- or ADP-induced aggregation was minimally affected. This inhibition was accompanied by a significant reduction in thromboxane A 2 (TXA 2 ) generation through the suppression of PLCγ2, cytosolic phospholipase A 2 (cPLA 2 ), and cyclooxygenase-1 (COX-1) signaling under collagen stimulation. In addition, genistein markedly inhibited PI3K/PDK1/Akt/GSK3αβ and MAPK (p38 and ERK) signaling pathways. Conversely, genistein enhanced cAMP-PKA-associated signaling, which was accompanied by reduced granule secretion, decreased integrin αIIbβ3 activation, and inhibition of clot retraction. These findings demonstrate that genistein exerts potent and agonist-preferential antiplatelet effects by interfering with collagen–GPVI-dependent signaling pathways. The study provides mechanistic insights into the antithrombotic potential of genistein and suggests that genistein may serve as a promising modulator of platelet activation in collagen-driven thrombotic conditions.