Adiponectin: Vascular Responses and Signaling Mechanisms

脂联素：血管反应和信号机制

• 批准号: 7066030
• 负责人: BARRY J. GOLDSTEIN
• 金额: $ 33.2万
• 依托单位: THOMAS JEFFERSON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-15 至 2008-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7066030
• 关键词: NAD(P)H dehydrogenase; adenosine monophosphate; biological signal transduction; cell adhesion molecules; cell cell interaction; diabetes mellitus; enzyme activity; free fatty acids; gene expression; genetically modified animals; hormone regulation /control mechanism; hyperglycemia; immunocytochemistry; insulin sensitivity /resistance; intravital microscopy; laboratory mouse; laboratory rat; low density lipoprotein; mitogen activated protein kinase; nitric oxide; nitric oxide synthase; nuclear factor kappa beta; protein structure function; tissue /cell culture; tumor necrosis factor alpha; vascular endothelium

DESCRIPTION (provided by applicant): Cardiovascular disease accounts for an overwhelming proportion of the morbidity and mortality suffered by patients with diabetes mellitus. Insulin resistance in obesity and type 2 diabetes, characterized by excess circulating non-esterified fatty acids (NEFA) and cytokines such as TNFalpha, and the hyperglycemia of overt diabetes are associated with endothelial dysfunction that contributes to the atherosclerotic process. Adiponectin is an abundant plasma protein secreted from adipose tissue that exhibits potent anti-inflammatory effects in the vasculature as well as insulin-sensitizing properties in metabolically-active tissues. In extensive preliminary studies, we have made the novel observations that the recombinant globular domain of adiponectin (gAd) exhibits a number of salutary effects in cultured endothelial cells, including enhanced nitric oxide (NO) production associated with activation of AMP kinase, and reduced superoxide generation induced by oxidized LDL (oxLDL) which is associated with cellular NAD(P)H oxidase activity. In addition, gAd inhibits superoxide production in endothelial cells exposed to high glucose, blocks the oxidation of native LDL by endothelial cells, and suppresses cell proliferation and MAP kinase activation stimulated by oxLDL. By quantitative intravital microscopy in the db/db mouse, we have also found in our initial studies that overexpression of gAd by adenoviral gene delivery in vivo ameliorates the increased leukocyte/endothelial interactions characteristic of the endothelial dysfunction in this model of insulin resistant type 2 diabetes. We propose here to combine studies of endothelial cells in vitro with intravital microscopy in situ to examine the cellular responses and signaling mechanisms of the two major forms of adiponectin (full-length and gAd) and test the hypotheses that adiponectin: (1) enhances NO production in states of endothelial dysfunction via an AMP kinase-linked pathway; (2) suppresses superoxide production by endothelial cells treated with oxLDL or high glucose, possibly via an NAD(P)H oxidase-linked pathway; and (3) ameliorates endothelial dysfunction in vivo in rodent models of obesity with insulin resistance and/or diabetes as evidenced by salutary effects on leukocyte/endothelial interactions, expression of cell adhesion molecules and NO production. These studies will provide insight into the cellular mechanisms employed by adiponectin to ameliorate endothelial dysfunction in states of insulin resistance and type 2 diabetes, and may lead to improved strategies to reduce the excessive cardiovascular risk associated with these disorders.

描述（由申请人提供）：心血管疾病占糖尿病患者遭受的发病率和死亡率的压倒性比例。肥胖症和2型糖尿病的胰岛素抵抗，其特征是过量循环的非酯化脂肪酸（NEFA）和细胞因子（例如TNFALPHA），以及明显的糖尿病的高血糖症与内皮功能障碍有关，导致了动脉粥样硬化过程。脂联素是一种从脂肪组织中分泌的丰富血浆蛋白，在脉管系统中表现出有效的抗炎作用，以及代谢活性组织中胰岛素敏感性的特性。在广泛的初步研究中，我们对脂联素（GAD）的重组球状结构域（GAD）的重组球状结构域在培养的内皮细胞中表现出了许多有益的作用，包括与AMP激酶激活相关的一氧化氮（NO）产生，以及与氧化氧化物诱导的氧化物（氧化物）相关联（P），氧化氧化物（NO）的产生（NO）与氧化物的生成减少相关（P）（P）（PE），PERSED（PAR）与氧化物的生成相关联（P）此外，GAD抑制暴露于高葡萄糖的内皮细胞中的超氧化物的产生，通过内皮细胞阻断天然LDL的氧化，并抑制细胞增殖和由OXLDL刺激的MAP激酶激活。通过DB/DB小鼠中的定量浸润显微镜，我们还发现，在初始研究中，腺病毒基因递送对GAD的过表达在体内减轻了这种胰岛素2型糖尿病模型中内皮功能障碍的白细胞/内皮相互作用的增加。我们在这里提议将体外内皮细胞的研究与原位浸润性显微镜结合起来，以检查两种主要形式的脂联素（全长和GAD）的细胞反应和信号传导机制，并测试脂结蛋白的假设：（1）通过在Ampkinase as amp kinase as amp kincase and Amp-Kincone; （2）可能通过NAD（P）H氧化酶连接途径抑制用OXLDL或高葡萄糖处理的内皮细胞产生的超氧化物； （3）在肥胖的啮齿动物模型中缓解体内内皮功能障碍具有胰岛素抵抗和/或糖尿病，这是对白细胞/内皮相互作用，细胞粘附分子的表达和无生产的有益作用所证明的。这些研究将洞悉脂联素在胰岛素抵抗和2型糖尿病状态下改善内皮功能障碍的细胞机制，并可能导致改进的策略，以减少与这些疾病相关的过度心血管风险。