BS39 Targeting BACE1 to improve angiogenesis in type 2 diabetes

Abstract

Sirtuin 1 (SIRT1) is an NAD+ dependent deacetylase with vasculoprotective properties, which maintains cardiometabolic homeostasis under oxidative stress and prevents ischaemiareperfusion injury. Patients at high risk of atherothrombosis, such as diabetics and obese, display reduced SIRT1 levels, which were associated with enhanced thrombus formation in a murine model of arterial thrombosis. However, the importance of SIRT1 in regulating platelet function has not been evaluated. The aim of this study was to investigate the effect of the SIRT1 activators on platelet function and assess their potential use as a novel antithrombotic therapy.Unless stated otherwise, all experiments were performed with platelets from healthy donors and SIRT1 was activated with SRT1720 10 μM.The expression of SIRT1 was confirmed in platelets by Western blotting. Using PBA, it was demonstrated that SIRT1 activation with SRT1720 attenuates platelet aggregation induced with collagen and TRAP-6. Further evaluation of the role of SIRT1 in platelet activation showed that SRT1720 causes a 50% decrease in fibrinogen binding and a 30% reduction in a-granule release. The effect of SIRT1 activation in cytoskeletal rearrangement during platelet activation was also explored. Incubation of platelets with SRT1720 significantly reduced actin polymerization after platelet stimulation. Activation of SIRT1 with SRT1720 inhibited platelet adhesion and spreading on collagen and fibrinogen, but it did not alter agonist-induced coiling of the tubulin ring, indicating that SIRT1 is involved in platelet actin cytoskeleton reorganization. This was further supported by clot retraction assays, which demonstrated that SIRT1 inhibition with EX 527 caused a dramatic reduction in clot retraction, represented by an increase in the clot weight and the area occupied by the thrombus at different time points.These results suggest that SIRT1 regulates platelet integrin aIIbβ3 activation and the subsequent cytoskeletal rearrangement. SIRT1 may therefore provide a novel therapeutic target to limit platelet activation and accelerate reperfusion after a thrombotic obstruction in a vessel while protecting against oxidative damage.