Decoding PGC-1a1 Control of Energy Metabolism

项目摘要 对抗肥胖症的一个主要挑战是确定可以减少能量摄入或减少肥胖的靶向途径。 增加能量消耗。其中一个最有前途的生物系统，可以利用，以增加 能量消耗是产热的棕色脂肪组织。不像白色脂肪组织储存能量 三酸甘油酯的形式，棕色脂肪组织氧化燃料，并通过解偶联ATP以热量形式耗散能量 在称为非颤抖产热的过程中从电子传递链合成。整体 我们研究的目的是了解非颤抖性产热的分子机制， 利用这些机制来对抗肥胖和相关疾病，包括2型糖尿病。PGC1α1 是一个关键的转录辅激活因子，促进棕色线粒体生物合成和产热， 脂肪组织事实上，更好地了解新的信号整合点到PGC1α1是非常必要的。 这些机制的鉴定和表征可能会导致发现新的方法来提高 能量消耗和对抗肥胖。本研究的目的是阐明蛋白质合成的作用， PGC 1 α1蛋白在脂肪组织产热代谢中起重要调节作用。我们 初步数据表明，胰岛素强烈诱导PGC1α1蛋白，而不依赖于mRNA水平， 对脂肪组织产热很重要。遗传学研究表明，胰岛素信号是重要的， 但其在调节PGC1α1翻译中的作用从未被探索过。因此我们 假设信号整合入PGC1α1的主要模式来自翻译水平，我们的目标是 来解码棕色脂肪细胞中的这些机制和生物学结果。我们提出以下目标， 测试这个假设： 1.目的1阐明PGC1α1非翻译区（UTR）在胰岛素分泌调控中的作用。 在原代棕色脂肪组织（BAT）细胞中的依赖性翻译。PGC1α1 mRNA转录本具有 目前还没有完全研究，UTR的功能也是未知的。因为我们有数据显示 提示PGC1α1受翻译调控，我们将检测UTR在这一过程中的作用。 2.目的2通过多核糖体技术研究BAT中PGC1α1的体内翻译调控。黄金 测量翻译的标准是mRNA通过多聚核糖体转化为翻译多聚核糖体 比色法我们将通过该测定来描述启动PGC1α1在体内翻译的上游信号。 3.目的3利用mRNA捕获技术鉴定PGC1α1的mRNA结合蛋白（RBP） 和质谱分析。一个开放的生物学问题是为什么某些mRNA被翻译而不是其他mRNA。 我们所追求的一个假设是，RBP通过结合某些mRNA并允许这种特异性， 他们在preferential条件下绑定的翻译复合体。在这里，我们使用PGC1α1作为测试用例 并寻找新的限制性商业惯例

Project Summary A major challenge for combating obesity is to identify targetable pathways that can decrease energy intake or increase energy expenditure. One of the most promising biological systems that can be exploited to increase energy expenditure is the thermogenic brown adipose tissue. Unlike white adipose tissue that stores energy in the form of triglycerides, brown adipose tissue oxidize fuels and dissipate energy as heat by uncoupling ATP synthesis from the electron transport chain in a process known as non-shivering thermogenesis. The overall goal of our studies is to understand the molecular mechanisms underlying non-shivering thermogenesis and to exploit these mechanisms to antagonize obesity and associated diseases including Type 2 Diabetes. PGC1α1 is a key transcriptional coactivator that facilitates mitochondrial biogenesis and thermogenesis in brown and adipose tissue. Indeed better understanding novel signal integration points into PGC1α1 are much needed. Identification and characterization of these mechanisms could lead to the discovery of novel ways to boost energy expenditure and antagonize obesity. The objective of this study is to delineate the role protein synthesis plays in regulating PGC1α1 protein expresion in adipose tissue thermogenesis and metabolism. Our preliminary data suggest that insulin strongly induces PGC1α1 protein indepdently of mRNA levels and it is important for adipose tissue thermogenesis. Genetic studies have revealed that insulin signaling is important for brown fat function, but its role in regulating PGC1α1 translation has never been explored. Thus, we hypothesize that a major mode of signal integration into PGC1α1 comes at the level of translation and we aim to decode these mechanisms and biological outcomes in brown adipocytes. We propose the following aims to test this hypothesis: 1. Aim 1 will define the role of the of the PGC1α1 untranslated region (UTR) in regulating its insulin- dependent translation in primary brown adipose tissue (BAT) cells. The PGC1α1 mRNA transcript has not been fully studied and the function of the UTR is currently unknown. Since we have data strongly suggesting that PGC1α1 is regulated by translation, we are going to test the role of the UTR in this process. 2. Aim 2 will study the in vivo regulation of PGC1α1 translation by polysome analysis in BAT. The gold standard for measuring translation is the transition of mRNA to translating polyribosomes by the polysome assay. We will delineate the upstream signals that initiate the translation of PGC1α1 in vivo by this assay. 3. Aim 3 will identify and characterize mRNA binding proteins (RBPs) of PGC1α1 using mRNA capture and mass spectrometry. An open biological question is why are certain mRNAs translated and not others. One hypothesis that we are pursuing is that RBPs allow this specificity by binding certain mRNAs and allowing them to bind the translation complex under preferetial conditions. Here, we are using PGC1α1 as a test case for this and search for novel RBPs.