PPAR gamma regulates vascular endothelial reactive species production in diabetes

描述(申请人提供)：血管疾病，包括心脏病发作和中风，是糖尿病患者死亡和疾病的主要原因。这项应用的长期目标是确定减少糖尿病血管疾病的新策略。活性氮和氧的平衡产生对正常血管功能的调节起着至关重要的作用。糖尿病增加了血管壁细胞的氧化应激，导致一氧化氮(NO)生物利用度降低和内皮功能障碍。这一建议探索了一种新的假设，即配体激活的转录因子，过氧化物酶体增殖物激活受体γ(PPARg)控制血管内皮细胞的基因表达程序，调节活性氮和氧物种的产生之间的平衡，以及PPARg刺激通过直接刺激内皮细胞PPARg增加NO的生物利用度而在体内发挥血管保护作用。PI已经证明，用噻唑烷二酮类化合物直接激活血管内皮细胞PPARg可增加内皮细胞NO的释放，并减少超氧化物的产生。目的1研究PPARg在体外和体内改变内皮细胞超氧化物代谢的机制。初步数据表明，PPARg的激活降低了糖尿病动物血管壁上NADPH氧化酶的表达和活性，并减轻了血管功能障碍。目的2明确PPARg激活在体外和体内调节eNOS活性的翻译后机制中的影响。由于PPARg配体不会增加内皮型一氧化氮合酶(ENOS)的表达，因此本研究的目的将集中在PPARg介导的eNOS活性的翻译后调节中的改变，包括eNOS-蛋白质相互作用和位点特异性eNOS磷酸化事件。目的3将测定正常和糖尿病内皮细胞特异性PPARg缺失小鼠的基础血管内皮细胞和噻唑烷二酮刺激的血管内皮细胞功能。这些创新研究将阐明内皮PPARg功能降低的血管后果，并允许分析内皮PPARg活性在血管功能中的具体影响。这项建议将阐明PPARg在糖尿病血管调节中的作用，并有助于制定更好的预防和治疗与内皮NO产生受损相关的血管疾病的策略。

DESCRIPTION (provided by applicant): Vascular disease, including heart attack and stroke, are major causes of death and illness in patients with diabetes. This long term goal of this application is to identify novel strategies to reduce vascular disease in diabetes. The balanced production of reactive nitrogen and oxygen species plays a critical role in the regulation of normal vascular function. Diabetes increases oxidative stress in vascular wall cells leading to reduced nitric oxide (NO) bioavailability and endothelial dysfunction. This proposal explores the novel hypothesis that the ligand-activated transcription factor, peroxisome proliferator-activated receptor gamma (PPARg) controls a program of gene expression in vascular endothelium that regulates the balance between the production of reactive nitrogen and oxygen species and that PPARg stimulation exerts vascular protective effects in vivo by directly stimulating endothelial PPARg to increase NO bioavailability. The PI has demonstrated that direct activation of vascular endothelial cell PPARg with thiazolidinediones increased endothelial cell NO release and reduced superoxide production. Aim 1 will examine mechanisms by which PPARg alters endothelial superoxide metabolism in vitro and in vivo. Preliminary data indicate that PPARg activation decreases the enhanced expression and activity of NADPH oxidase in the vascular wall of diabetic animals and attenuates vascular dysfunction. Aim 2 will define the impact of PPARg activation on post- translational mechanisms regulating eNOS activity in vitro and in vivo. Because PPARg ligands do not increase the expression of endothelial nitric oxide synthase (eNOS), this aim will focus on PPARg-mediated alterations in the post-translational regulation of eNOS activity including eNOS-protein interactions and site- specific eNOS phosphorylation events. Aim 3 will determine basal and thiazolidinedione-stimulated vascular endothelial function in normal and diabetic endothelial-specific PPARg null mice. These innovative studies will clarify the vascular consequences of reduced endothelial PPARg function and permit analysis of specific effects of endothelial PPARg activity in vascular function. This proposal will clarify roles of PPARg in vascular regulation in diabetes and contribute to the development of improved strategies for the prevention and treatment of vascular disease associated with impaired endothelial NO production.