Optogenetic Toolbox for Studying Regulators of G-Protein Signaling in Addiction

 描述(申请人提供)：G蛋白信号调节蛋白(RGS)是GTP酶加速蛋白(GAP)，通过负调控微调G蛋白偶联受体(GPCR)信号的时间和强度。RGS蛋白在成瘾中起着重要的病理生理作用，其中有三种RGS蛋白在中脑边缘通路中高表达(RGS2、RGS4和RGS9-2)。这些亚型已被证明影响关键的u阿片和多巴胺受体的信号传递，并在对滥用药物(如吗啡和可卡因)的反应中表达水平不同。体内对单个亚型的研究可能很困难，因为补偿活动在基因敲除动物中产生了微妙的表型，以及它们的催化域的高度保守的性质，使得创造选择性小分子配体在药理学上具有挑战性。我们建议创造新的光遗传学工具，能够以时空精确和细胞类型特定的方式双向激活和抑制单个RGS亚型。这种体内动态的RGS亚型特异性控制将有力地连接分子水平的细胞内信号事件和细胞类型水平的神经回路动力学，从而为我们基本理解RGS在成瘾中的作用及其作为治疗靶点和生物标记物的有效性带来重大的方法学进步，这些事件共同构成下游成瘾表型的机械基础。

 DESCRIPTION (provided by applicant): Regulators of G-protein signaling (RGS) are GTPase accelerating proteins (GAP) that fine-tune the timing and intensity of G-protein coupled receptor (GPCR) signaling through negative regulation. RGS proteins play important pathophysiological roles in addiction, with three RGS proteins in particular highly expressed in the mesolimbic pathway (RGS2, RGS4, and RGS9-2). These subtypes have been shown to influence the signaling of key mu-opioid and dopamine receptors, and vary in expression levels in response to drugs of abuse such as morphine and cocaine. The study of individual subtypes in vivo can be difficult due to compensatory activity that gives rise to subtle phenotypes in knockout animals, as well as the highly conserved nature of their catalytic domains that makes it pharmacologically challenging to create selective small molecule ligands. We propose to create new optogenetic tools that will enable the bi-directional activation and inhibition of individual RGS subtypes in a spatio-temporally precise and cell-type specific manner. This type of dynamic RGS subtype-specific control in vivo will bring a major methodological advance toward our basic understanding of RGS roles in addiction and their validation as therapeutic targets and biomarkers, by powerfully bridging the molecular level intracellular signaling events and cell type-level neural circuit dynamics that together mechanistically underlie downstream addictive phenotypes.