Abstract 17640: Glucose Metabolism is Essential for Platelet Function
Upon activation, platelets utilize stored glycogen, increase glucose uptake, glycolysis and glucose oxidation. Moreover, platelets incubated under hyperglycemic conditions and platelets isolated from diabetic patients display increased markers of activation. We therefore tested the hypothesis that glucose metabolism is essential for platelet function by generating mice lacking both glucose transporter 1 (GLUT1) and glucose transporter 3 (GLUT3) specifically in platelets. Glucose uptake in GLUT1/GLUT3 double knockout (DKO) platelets was nearly zero and glycolysis was markedly attenuated. In the presence of the mitochondrial substrates glutamate and pyruvate, mitochondrial respiration increased 3-fold due to a qualitative adaptation, as electron micrographs revealed normal mitochondrial number and morphology. DKO mice displayed a ~30% reduction in platelet counts, and decreased circulating platelet half-life. In vitro, DKO platelets displayed increased phosphatidylserine exposure to the outer leaflet of the plasma membrane marked by annexin v binding, which increased in a time dependent manner. DKO platelets incubated for 6 hours in 5mM glucose media displayed ~30% annexin v binding with reduced mitochondrial potential and increased caspase 3/7 activity, compared to <5% in controls. Interestingly, addition of mitochondrial substrates pyruvate and glutamate decreased annexin v binding. In response to PAR4 peptide, convulxin, ADP, U46619, and thrombin plus convulxin, DKO platelets display impaired GPIIbIIIa activation and CD62p surface translocation. Stimulation with thrombin plus convulxin could not increase calcium flux in DKO platelets. In addition administration of the calcium ionophore ionomycin did not restore platelet GPIIbIIIa activation or CD62p surface translocation suggesting that glucose metabolism is essential for platelet activation upstream and downstream of calcium signaling. In vivo DKO mice subjected to tail bleeding or FeCl3 induced arterial thrombosis exhibited increased time to occlusion and in a model of pulmonary embolism DKO mice demonstrated increased survival. Together these data indicate that glucose metabolism is essential for platelet survival, circulating half-life, and activation.
Author Disclosures: T.P. Fidler: None. T. Funari: None. N.G. Dunne: None. R.A. Campbell: None. A.S. Weyrich: None. E. Abel: None.
- © 2016 by American Heart Association, Inc.