Hypothalamic Integration of Energy Homeostasis Signals

肥胖的动态平衡控制依赖于大脑对身体能量储存循环指标变化的感知和反应能力。这一建议侧重于了解下丘脑弓状核中两组神经元的分子和细胞机制，这些神经元以Agti相关蛋白的表达为标志 蛋白质(AgRP)和前阿片黑素皮质素(POMC)，测量并响应瘦素、胰岛素和Ghrelin的变化。转基因技术和分子成像的最新进展使我们的方法成为可能，并基于工具的开发，这些工具允许我们控制AgRP/NPY和Pomc/CART神经元中的基因表达。 利用细菌人工染色体(BAC)克隆在大肠杆菌中的同源重组，然后将修饰克隆转基因导入小鼠体内，我们将Cre重组酶置于AgRP或POMC基因调控元件的控制之下。这些Tg.AgpCre和Tg.PomcCre小鼠将被应用于更好地了解外围设备 通过构建和分析在AgRP神经元、POMC神经元或两者中都缺乏STAT3或Irs2的小鼠的表型，下丘脑神经元可以感知和整合身体燃料储存和进食模式的信号。我们还将使用一种新开发的方法来动态测量单个细胞中的肌醇磷脂3-激酶信号，以确定弓状核神经元的每一亚群对瘦素、胰岛素或生长激素的反应。 在脑片准备过程中。最后，我们将确定增加长链脂肪酰辅酶A水平的药物是否以及如何与AgRP和POMC神经元中的Stag和PI3K信号交叉。总之，这些研究将为控制关键下丘脑神经元对激素和营养相关信号的反应的细胞机制提供基本的新见解。

Homeostatic control of adiposity depends on the ability of the brain to sense and respond to changes in circulating indicators of body energy stores. This proposal is focused on understanding the molecular and cellular mechanisms by which two groups of neurons in the arcuate nucleus of the hypothalamus, those marked by expression of Agouti-related protein (Agrp) and Preproopiomelanocortin (Pomc), measure and respond to changes in leptin, insulin, and ghrelin. Our approach has been made possible by recent advances in transgenic technology and molecular imaging, and is based on the development of tools that allow us to control gene expression specifically in the Agrp/Npy and Pomc/Cart neurons. Using homologous recombination of bacterial artificial chromosome (BAC) clones in E. coli followed by transgenic introduction of the modified clones into mice, we have placed Cre recombinase under control of regulatory elements for the Agrp or Pomc genes. These Tg.AgrpCre and Tg.PomcCre mice will be applied to better understand how peripheral signals of body fuel stores and meal patterning are perceived and integrated by hypothalamic neurons by constructing and analyzing the phenotype of mice that are deficient for Stat3 or for Irs2 in either Agrp neurons, Pomc neurons, or both. We will also use a newly developed assay for dynamic measurement of phosphoinositide 3-kinase signaling in individual cells to determine how each subpopulation of arcuate nucleus neurons responds to leptin, insulin, or ghrelin in a brain slice preparation. Finally, we will determine if and how agents that increase long chain fatty acyl CoA levels intersect with Stag and PI3K signaling in Agrp and Pomc neurons. Together, these studies will provide fundamental new insight into cellular mechanisms governing the response of key hypothalamic neurons to hormonal and nutrient-related signals.