Mitochondrial Biogenesis and Endothelial Cell Phenotype

描述（申请人提供）：内皮是正常血管稳态的重要组成部分，内皮功能障碍是血管疾病及其临床表现（如心脏病发作和中风）发展的前奏。内皮功能障碍被认为部分是由血管疾病危险因素（如高胆固醇血症、高血压和糖尿病）的损伤作用引起的。对内皮功能障碍和损伤的抵抗是对抗血管疾病的重要保护机制，因为保留内皮功能的患者不容易发生临床血管事件。然而，决定内皮功能障碍易感性或抗性的精确分子事件尚不清楚。本研究的初步数据表明，代谢应激反应的诱导（通过AMP激酶激活）刺激线粒体生物发生，保护内皮细胞免受有害刺激。此外，我们的数据将这种保护作用与抑制c-Jun n -末端激酶激活联系起来，这是环境应激反应的关键组成部分。因此，我们的中心假设是代谢应激反应和由此产生的线粒体生物发生刺激是内皮细胞表型和抵抗有害刺激的关键决定因素。因此，本应用的目的是确定代谢应激和线粒体生物发生调节内皮功能的分子机制，并验证内皮细胞对功能障碍的抵抗力增强将改善血管疾病发展的假设。为了实现这一目标，我们将首先确定代谢应激反应的组成部分和保护内皮细胞免受有害刺激所需的线粒体生物发生。我们将使用药理学（AICAR， 2-脱氧葡萄糖）和分子（PGC-11, RIP140）手段模拟代谢应激，并量化线粒体生物发生。然后，我们将使用药理学（氯霉素）和分子（Tfam）工具将代谢应激反应与线粒体生物发生分离，并确定其对内皮保护的影响。然后，我们将探讨已知代谢靶点如eNOS、FOXOs和sirt1在内皮应激抵抗中的作用。接下来，我们将确定代谢应激反应和线粒体生物发生减弱JNK激活的机制。代谢应激和线粒体生物发生将被控制，我们将通过研究重要的上游（MAP3K和MAP2K）激酶以及通过化学遗传方法涉及的特定JNK亚型来研究对JNK激活的影响。然后，我们将研究JNK失活的重要决定因素，如ROS和MAP激酶磷酸酶。最后，使用化学遗传学方法，我们将确定JNK调控的时间方面。最后，我们将在体内确定操纵内皮细胞线粒体生物发生对内皮功能障碍和血管疾病的影响。我们已经开发了工具来操纵内皮细胞PGC11作为线粒体生物发生和体内质量的模型。通过这些动物，我们将确定内皮细胞PGC11对线粒体生物发生和质量的影响，以及内皮细胞对高血压和动脉粥样硬化相关功能障碍的抵抗。上述实验应该为我们提供一个坚实的工作知识，线粒体生物发生和线粒体质量增加如何有助于内皮表型的控制，以及这如何转化为体内的稳态反应。有了这些信息，我们应该有必要的洞察力来设计新的工具来调节血管氧化还原状态和表型，并着眼于血管疾病的治疗。公共卫生相关性：内皮是血管的内膜，它的行为是血管的重要控制点。我们从经验中知道，有动脉粥样硬化风险的人的血管不能正常工作。事实上，那些血管功能最差的人患心脏病的风险最高。在这一提议中，我们提供的证据表明，线粒体在内皮细胞的数量决定血管的正常行为。我们还开发了一些工具，我们可以改变内皮中线粒体的数量，我们相信，改变血管的行为，使它们更像没有动脉粥样硬化的正常血管。因此，该提案包含了确定线粒体（“细胞的动力”）如何控制血管行为的实验。这些实验应该为我们提供设计治疗动脉粥样硬化的新疗法所需的知识。

DESCRIPTION (provided by applicant): The endothelium is an important component of normal vascular homeostasis and endothelial dysfunction is a prelude to the development of vascular disease and its clinical manifestations such as heart attack and stroke. Endothelial dysfunction is thought to result, in part, from the injurious actions of established vascular disease risk factors such as hypercholesterolemia, hypertension, and diabetes. Resistance to endothelial dysfunction and injury is an important protective mechanism against vascular disease, as patients with preserved endothelial function are not predisposed to clinical vascular events. However, the precise molecular events that determine susceptibility or resistance to endothelial dysfunction are not known. Preliminary data presented in this application indicate that induction of a metabolic stress response (via AMP kinase activation) stimulates mitochondrial biogenesis and protects the endothelium from injurious stimuli. Furthermore, our data link this protective effect to suppression of c-Jun N-terminal kinase activation - a key component of the environmental stress response. Therefore, our central hypothesis is that the metabolic stress response and resultant stimulation of mitochondrial biogenesis are key determinants of endothelial cell phenotype and resistance to injurious stimuli. The objective of this application, therefore, is to determine the molecular mechanism(s) whereby metabolic stress and mitochondrial biogenesis modulate endothelial function and test the hypothesis that increased endothelial cell resistance to dysfunction will ameliorate the development of vascular disease. In order to achieve this objective, we will first determine the component(s) of the metabolic stress response and mitochondrial biogenesis required to protect the endothelium from injurious stimuli. We will model metabolic stress using pharmacologic (AICAR, 2-deoxyglucose) and molecular (PGC-11, RIP140) means and quantify mitochondrial biogenesis. We will then dissociate the metabolic stress response from mitochondrial biogenesis using pharmacologic (chloramphenicol) and molecular (Tfam) tools and determine the implications for endothelial protection. We will then probe the involvement of known metabolic targets such as eNOS, FOXOs, and SIRT1in endothelial stress resistance. Next we will determine the mechanism(s) whereby the metabolic stress response and mitochondrial biogenesis attenuates JNK activation. Metabolic stress and mitochondrial biogenesis will be manipulated and we will examine the implications for JNK activation by investigating important upstream (MAP3K and MAP2K) kinases as well as the specific JNK isoforms involved via a chemical genetic approach. We will then examine important determinants of JNK inactivation such as ROS and MAP kinase phosphatases. Finally, using a chemical genetic approach, we will determine temporal aspects of JNK regulation. Finally, we will determine the implications of manipulating endothelial cell mitochondrial biogenesis on endothelial dysfunction and vascular disease in vivo. We have developed tools to manipulate endothelial cell PGC11 as a model of mitochondrial biogenesis and mass in vivo. Using these animals, we will determine the implications of endothelial cell PGC11 on mitochondrial biogenesis and mass and endothelial resistance to the dysfunction associated with hypertension and atherosclerosis. The experiments outlined above should provide us with a solid working knowledge of how mitochondrial biogenesis and increased mitochondrial mass contributes to the control of endothelial phenotype and how this translates into homeostatic responses in vivo. With this information in hand, we should have the requisite insight to design new tools directed at modulating vascular redox status and phenotype with an eye toward the treatment of vascular disease. PUBLIC HEALTH RELEVANCE: The endothelium is the lining of blood vessels and its behavior is an important control point for blood vessels. We know from experience that blood vessels in people at risk for atherosclerosis do not work normally. In fact, those individuals with the worst function in their blood vessels are at the highest risk for heart attack. In this proposal, we provide evidence that the number of mitochondria in the endothelium determines the normal behavior of blood vessels. We have also developed some tools where we can change the number of mitochondria in the endothelium and, we believe, change the behavior of blood vessels such that they act more like normal vessels without atherosclerosis. Therefore, this proposal contains experiments to determine how mitochondria, the "powerhouse of the cell," controls the behavior of blood vessels. These experiments should provide us with the knowledge we need to design new therapies for treating atherosclerosis.