AMPK Endothelial Cell Dysfunction and the Metabolic Syndrome (PROGRAM PROJECT)

代谢综合征在临床上被定义为一种以血脂异常、高血压、向心性肥胖、高血糖和过早发生动脉粥样硬化性心血管疾病和2型糖尿病为特征的疾病。此外，它与微血管稀疏和血管生成受损有关。在人类和实验动物中，代谢综合征通常伴有胰岛素抵抗、脂质异常和促炎状态，并且在此之前。我们和其他人提出，这些异常可能是燃料敏感酶AMP激活蛋白激酶（AMPK）失调的结果。该计划将集中在内皮细胞，这是一般认为是第一个血管细胞在动脉粥样硬化和受损的血管生成过程中改变。将检验两个主要假设：1）与代谢综合征相关的血管异常部分由AMPK的失调引起，2）这种失调是SIRT 1/2受损的结果，我们已经证明的LKB 1信号传导机制调节体内各种培养细胞和肝脏中的AMPK活性（参见项目1）。这三个项目将单独和共同的特点SIRT 1/LKB 1/AMPK机制在培养的血管内皮细胞，并确定其激活和抑制的影响，对葡萄糖，FFA和TNF？（项目1，2）和对缺血的血管生成反应（项目3）。我们还将探讨氧化应激导致SIRT 1的翻译后修饰的假设，这可以通过AMPK激活来预防（项目2，1）。最后，我们将开发具有SIRT 1或LKB 1（核心B）的内皮细胞特异性缺失的转基因小鼠。然后，我们将评估这些缺失对对照小鼠和喂食高脂肪/高蔗糖饮食的小鼠中的肌肉毛细作用（项目3和1）和主动脉中的致动脉粥样硬化变化（项目2）的影响。此外，我们将评估运动对这些小鼠的抗动脉粥样硬化和促血管生成作用（项目1-3）。由于研究的互动性和使用多个研究者最有效研究的实验模型，因此要求获得项目资助。代谢综合征影响美国超过60，000，000名20岁以上的人，是一个主要的公共卫生问题。拟议的研究应产生新的见解，为过早动脉粥样硬化和血管生成受损与此实体相关的生物学基础，并提出新的治疗目标，为他们的预防。

The metabolic syndrome has been defined clinically as a disorder characterized by dyslipidemia, hypertension, central obesity, hyperglycemia and a predisposition to premature atherosclerotic cardiovascular disease and type 2 diabetes. In addition it is associated with microvascular rarefaction and impaired angiogenesis. In both humans and experimental animals the metabolic syndrome is typically accompanied and preceded by insulin resistance, lipid abnormalities and a proinflammatory state. We and others have proposed that these abnormalities could be the result of dysregulation of the fuel-sensing enzyme AMP-activated protein kinase (AMPK). This program will focus on the endothelium, which is generally believed to be the first vascular cell altered during both atherogenesis and impaired angiogenesis. Two major hypotheses will be tested: 1) that the vascular abnormalities associated with the metabolic syndrome are caused in part by dysregulation of AMPK (decreased basal activity or impaired activation) in the endothelial cell as well as peripheral tissues and 2) that such dysregulation is the result of impairment of a SIRT1/LKB1 signaling mechanism that we have demonstrated regulates AMPK activity in various cultured cells and in the liver in vivo (See Project 1). The three projects will individually and collectively characterize the SIRT1/LKB1/AMPK mechanism in cultured vascular endothelial cells and determine the effects of its activation and inhibition on the proatherogenic effects of glucose, FFA and TNF? (Projects 1, 2) and the angiogenic response to ischemia (Project 3). We will also explore the hypothesis that oxidative stress causes post-translational modifications of SIRT1 that can be prevented by AMPK activation (Projects 2, 1). Finally, we will develop transgenic mice with an endothelial cell specific deletion of SIRT1 or LKB1 (Core B). We will then assess the effect of these deletions on muscle capillarity (Projects 3 and 1) and atherogenic changes in the aorta (Project 2) in control mice and mice fed a high-fat/high sucrose diet. In addition, we will assess the anti-atherogenic and pro-angiogenic effects of exercise in these mice (Projects 1-3). A program project grant is requested because of the interactive nature of the research and the use of experimental models that are most effectively studied by multiple investigators. The metabolic syndrome affects over 60,000,000 people in the U.S. over the age of 20 and is a major public health problem. The proposed studies should both yield novel insights into the biological bases for the premature atherosclerosis and impaired angiogenesis associated with this entity and suggest new therapeutic targets for their prevention.