High-throughput assays for GPCR in obesity research

描述（由申请人提供）：肥胖现已成为一个重大的健康问题。肥胖是维持能量使用和能量储存之间的稳态的系统不平衡的结果。该系统依赖于源自位于外围的能量存储器的感测信号。外周信号汇聚到CMS中，在下丘脑中，它们被整合，并且传出反应的方向和幅度被确定。几种神经肽在整合下丘脑中的外周信号中起主要作用，特别是蛙皮素样肽。这些神经肽激活三种受体，但其中一种称为BRS-3受体，是对摄食行为影响最明显的受体。缺乏BRS-3受体的小鼠是摄食过度的，并且显示出增加的摄食效率。它们代表了晚发性肥胖的模型系统。因此，需要研究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学试验能够鉴定能够激活或抑制BRS-3受体的配体。蛙皮素样肽对BRS-3的活化较差，不能在体内使用。此外，BRS-3受体的天然配体未知。因此，我们建议通过建立可用于分离合成激动剂或拮抗剂以研究BRS-3系统的筛选测定来帮助缓解这种缺乏。 我们将首先利用对人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受体的筛选测定。这些试验将被设计为允许监测受体反应性或受体结合。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。我们将最终使用该配体建立大鼠和小鼠特异性筛选方法。

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.