Aspirin Inhibition of ñ-Granules Release is Associated with Sirt1/AMPKand PI3K/Akt Pathway in Thrombin-Activated Platelets

Abstract

Objectives: To investigated the effect of aspirin on inhibition of platelet α-granules release in thrombin-activated platelets. Methods: Human platelets were used in the present study. Protein expression and phosphorylation was determined by Western blot. The secreted CD40L and PF4 from platelets were detected by ELISA. Results: Aspirin reduced CD40L and PF4 expression in thrombin-activated platelets. Sirt1 expression and AMPK phosphorylation was decreased by 24.4% and by 19.2% in thrombin-activated platelets. In contrast, aspirin dosedependently recovered Sirt1 expression and AMPK phosphorylation. EX527 (a Sirt1 inhibitor) treatment resulted in an increase in CD40L and PF4 expression. The combination of EX527 and aspirin weakened the inhibitory effect of aspirin on platelet aggregation, the expression of CD40L and PF4. Moreover, aspirin abolished the phosphorylation of Akt inthrombin-activated platelets. Aspirin has a synergistic action with LY294002 (an Akt inhibitor) on inhibition of thrombin-induced CD40L and PF4 expression. Conclusions: Our results provide new evidence that the aspirin inhibiting platelet α-granules release not only is associated with suppressing Akt activation but also linked to activating Sirt1/AMPK pathway in thrombin-activated platelets