PGC-1 and Nuclear Receptors in Adaptive Thermogenesis

描述（由申请人提供）：真核生物依靠线粒体有效地产生ATP，但同样的细胞器是活性氧（ROS）的主要来源，这是一种内源性毒素。线粒体!功能障碍与许多疾病有关，包括2型糖尿病、肥胖和神经退行性疾病。最近的工作，包括之前由该基金资助的许多工作，已经表明PGC-1转录共激活因子将线粒体功能与许多组织中的细胞内外环境联系起来。这项新的资助提出了探索pgc - 1a在正常生理和一些涉及线粒体功能障碍的疾病中的作用的实验。我们的第一个目标是确定pgc - 1a在小鼠糖尿病和肥胖发展中的作用，使用我们制造的肌肉特异性KO。小鼠将在基础状态和高脂肪喂养和衰老的挑战下进行研究。葡萄糖稳态将通过葡萄糖耐量试验和高胰岛素-血糖钳测定。我们还将研究pgc - 1a存在和不存在情况下的肌肉纤维类型和跑步表现。我们的第二个目标将集中在AMP激酶和pgc - 1a在体外和体内的合作。我们的新数据表明，AMPK在体外和细胞中直接磷酸化pgc - 1a，并需要pgc - 1a调节某些基因表达程序。在我们的第三个目标中，我们最近发现pgc - 1a具有强大的抑制ROS形成的能力，因为它激活线粒体呼吸。事实上，ROS诱导ROS解毒程序的能力依赖于PGC-1 a和PGC-1 p。我们将确定允许ROS诱导PGC-1 a的关键分子事件，反过来，试图了解PGC-1 a所依赖的转录因子来启动ROS解毒程序。我们还将尝试创建具有突变基因PGC-1的小鼠品系，该基因仍然可以调节OXPHOS但不能调节ROS，并研究其在代谢性疾病中的作用。这些研究应该为调节氧化代谢的方式提供新的机会，从而为一些重要的人类疾病提供新的方法。

DESCRIPTION (provided by applicant): Eukaryotes rely on mitochondria to produce ATP efficiently, yet this same organelle is the major source of reactive oxygen species (ROS), an endogenous toxin. Mitochondria! dysfunction has been associated with many disorders including type 2 diabetes, obesity and neurodegenerative diseases. Recent work, including much that was funded previously by this grant, has shown that the PGC-1 transcriptional coactivators link mitochondrial function to the external and extracellular environment in many tissues. This new grant proposes experiments that probe the role of PGC-1 a in normal physiology and in a number of diseases involving mitochondrial dysfunction. Our first Aim will determine the role PGC-1 a in the development of diabetes and obesity in mice, using a muscle-specific KO we have made. Mice will be studied in the basal state and under challenges of high-fat feeding and aging. Glucose homeostasis will be measured with glucose tolerance tests and hyperinsulinemic-euglycemic clamps. We will also study muscle fiber-types and running performance in the presence and absence of PGC-1 a. Our second Aim will be focused on the collaboration in vitro and in vivo between AMP kinase and PGC-1 a. Our new data indicates that AMPK directly phosphorylates PGC-1 a in vitro and in cells, and requires PGC-1 a to modulate certain programs of gene expression. In our third Aim, we have recently found that PGC-1 a has a powerful ability to suppress the formation of ROS, as it activates mitochondrial respiration. Indeed the ability of ROS to induce a ROS detoxification program is dependent on PGC-1 a and PGC-1 p. We will determine the key molecular events that allow ROS to induce PGC-1 a and, conversely, attempt to understand the transcription factors on which PGC-1 a docks to turn on the ROS detoxification program. We will also attempt to create strains of mice with a mutant PGC-1 a gene which can still regulate OXPHOS but not ROS, and study effects in metabolic disease. These studies should provide new opportunities to modulate oxidative metabolism in ways that allow for new approaches to some important human diseases.