Metabolic Regulation of Platelet Reprogramming

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The overall goal of the University of Utah Molecular Medicine Translational Research Center in Thrombosis (U2M2-TRCT) is to test the hypothesis that the abnormal metabolic milieu in type 2 diabetes (T2DM) and the metabolic syndrome (MS) leads to genetic and metabolic reprogramming of platelets. This reprogramming directly contributes to the increase in platelet activation that characterizes these subjects who are at increased risk for thrombosis. The specific focus of project 2 is to elucidate the mechanisms that are responsible for the metabolic reprograming that develops in platelets of humans and mouse models of T2DM and the MS, and to determine if the associated changes in platelet metabolism will directly contribute to platelet dysfunction. Our preliminary studies reveal that diabetes alters metabolome profiles of platelets with changes consistent with increased glycolysis and TCA (tricarboxylic acid) flux and accumulation of lipid intermediates. In addition, transcriptional profiling reveals significant changes in the expression of genes that regulate mitochondrial energetics, coupling efficiency (e.g. UCP2) and mitochondrial dynamics (e.g. Mfn2). Thus we hypothesize that the metabolic milieu of T2DM and the MS increases platelet glucose utilization and mitochondrial metabolism that induces mitochondrial oxidative stress, leading to platelet activation. In aim 1 we will test the hypothesis that T2DM and the MS leads to mitochondrial dysfunction, characterized by mitochondrial uncoupling, ROS overproduction and impaired mitochondrial dynamics. In aim 2 we will determine the mechanisms by which T2DM and the MS alter mitochondrial function and will test the hypothesis that manipulation of these mechanisms (i.e., KO of platelet superoxide dismutase 2, UCP2 and Mfn2) are sufficient to modulate platelet activity. In aim 3 we will determine the contribution of increased platelet glucose utilization to platelet hyperactivation in T2DM and the MS. This hypothesis will be addressed in studies of diabetic murine models with genetic reduction or augmentation in platelet glucose transport. Collectively these studies will shed new insight into mechanisms that alter platelet metabolism and function in obesity and diabetes.