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

 描述（由申请人提供）：G蛋白信号传导调节因子（RGS）是通过负调节微调G蛋白偶联受体（GPCR）信号传导的时间和强度的GT3加速蛋白（GAP）。RGS蛋白在成瘾中发挥重要的病理生理作用，其中三种RGS蛋白特别在中脑边缘通路中高度表达（RGS 2、RGS 4和RGS 9 -2）。这些亚型已被证明会影响关键的μ-阿片样物质和多巴胺受体的信号传导，并在响应滥用药物（如吗啡和可卡因）时表达水平不同。由于在敲除动物中产生微妙表型的补偿活性，以及其催化结构域的高度保守性质，在体内研究单个亚型可能是困难的，这使得产生选择性小分子配体具有挑战性。我们建议创建新的光遗传学工具，其将能够以时空精确和细胞类型特异性的方式双向激活和抑制个体RGS亚型。这种类型的动态RGS亚型特异性控制在体内将带来一个重大的方法上的进步，我们的基本理解RGS在成瘾中的作用，并验证其作为治疗靶点和生物标志物，通过有力地桥接分子水平的细胞内信号传导事件和细胞类型水平的神经回路动力学，共同机械地构成下游成瘾表型的基础。

 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.