High-throughput assays for GPCR in obesity research

描述(申请人提供)：肥胖现已成为一个严重的健康问题。肥胖是维持能量消耗和储存能量之间动态平衡的系统失衡的结果。该系统依赖于来自位于外围的能量存储的感测信号。外周信号汇聚到下丘脑的CMS，在那里它们被整合在一起，在那里传出反应的方向和大小被确定。几种神经肽在整合下丘脑的外周信号方面起着重要作用，尤其是蛙皮素样肽。这些神经肽激活了三种受体，但其中一种被称为BRS-3受体的受体对摄食行为有最显著的影响。缺乏BRS-3受体的小鼠会出现巨噬，并表现出更高的摄食效率。它们代表了迟发性肥胖症的一个模型系统。因此，有必要研究BRS-3系统在啮齿动物体内的作用。然而，这是不可能的，因为目前还没有药理实验可以识别可以激活或抑制BRS-3受体的配体。蛙皮素样肽对BRS-3的激活作用很差，不能在体内使用。此外，BRS-3受体的天然配体尚不清楚。因此，我们建议通过建立可用于分离合成激动剂或拮抗剂的筛选分析来帮助缓解这一不足，以便研究BRS-3系统。 我们将首先利用一种与人BRS-3受体具有高亲和力但不激活大鼠BRS-3的合成肽来建立人BRS-3受体的筛选方法。这些分析将被设计成允许监测受体的反应性或受体结合。然后，我们将继续完成我们的初步研究，表明我们能够识别大鼠BRS-3受体的天然配体。我们最终将利用该配体建立大鼠和小鼠的特异性筛选方法。

DESCRIPTION (provided by applicant): Obesity has now become a significant health problem. Obesity is the result of an imbalance in the system that maintains the homeostasis between energy used and energy stored. This system relies on sensing signals originating in the energy stores located in the periphery. The peripheral signals converge into the CMS, in the hypothalamus where they are integrated and where the direction and magnitude of the efferent responses are determined. Several neuropeptides play major roles in integrating the peripheral signals in the hypothalamus in particular the bombesin-like peptides. These neuropeptides activate three receptors but one, called the BRS-3 receptor, is the one that has the most pronounced effect on feeding behavior. Mice devoid of BRS-3 receptor are hyperphagic and show increased feeding efficiency. They represent a model system for late onset obesity. There is therefore a need to study the effects that BRS-3 system has in vivo in rodents. This is however not possible because there exist no pharmacological assay that would allow to identify a ligand that could activate or inhibit the BRS-3 receptor at present. The bombesin-like peptides activate poorly BRS-3 and cannot be used in vivo. Moreover the natural ligand of the BRS-3 receptor is unknown. We therefore propose to help palliate this lack by establishing screening assays that can be used to isolate synthetic agonists or antagonists in order to study the BRS-3 system. We will first take advantage of a synthetic peptide that has high affinity for the human BRS-3 receptor, but that does not activate the rat BRS-3, to establish screening assays for the human BRS-3 receptor. These assays will be devised to allow for monitoring either receptor reactivity or receptor binding. We will then pursue to completion our preliminary studies that indicate that we are able to identify the natural ligand of the rat BRS-3 receptor. We will finally use this ligand to establish rat and mouse specific screening assay.