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Show HONORS COLLEGE SPRING 2013 Bushra Hussein Dale Abel PLATELET SPECIFIC KNOCKOUT OF SUPEROXIDE DISMUTASE 2 Bushra Hussein (Dale Abel) Division of Endocrinology, Diabetes and Metabolism University of Utah Platelets are anuclear cells, which circulate in the blood and aid in coagulation. Patients with increased platelet activation have a higher risk for the development of blood clots, which can lead to ischemic events, stroke, or pulmonary embolism. Increased reactive oxygen species (ROS) in platelets promote increased coagulation and thrombosis. An important protein involved in regulating ROS is superoxide dismutase 2 (SOD2). SOD2 is a mitochondrial protein, which converts toxic superoxide anions (02-)-produced during oxidative metabolism-into less toxic hydrogen peroxide. To better understand the relationship between increased oxidative stress and increased platelet aggregation w e generated a platelet specific SOD2 knockout mouse utilizing a Cre recombinase LOX-P system. Genotypes were verified by PCR of genomic D N A isolated from ear clippings obtained from mutant mice. Western blot analysis of SOD2 showed a nine-fold decrease in SOD2 expression based on densitometry, thus confirming the SOD2 protein knockout. The model is designed to increase the levels of 02- in the mitochondria leading to increased oxidative stress. W e tested the hypothesis that increased superoxide in the mitochondria will result in increased coagulation as demonstrated through a tail-bleed assay. W e investigated if the SOD2 knockout resulted in an in vivo bleeding phenotype. W e examined the time required to stop bleeding (KO 71 + 11 seconds, Control 60+21 seconds, p=0.40) in cut mouse-tails as well as the time until rebleed (KO 120+13 seconds, Control 170 +78 seconds, p=0.25). From these data we conclude that deletion of SOD2 in platelets does not impair coagulation in mice as under normal conditions, gross clotting parameters were unaffected by the loss of SOD2 in platelets. |
