DEVELOPMENT OF HIGH DENSITY DRUG SCREENING OF NEURAL GPCR's USING STEP ARRAYS

描述(申请人提供)：基因组学和蛋白质组学的最新进展在药物发现方面产生了快速变化，通过对分离的蛋白质靶标使用简单的分析来提高高通量筛选(HTS)方法的速度，但牺牲了信息深度，并使决定在流水线中寻找哪些化合物变得困难。因此，人们认识到对更智能的筛查平台的需求，特别是强调细胞系统生物学的平台。更复杂的筛选策略对于发现针对G蛋白偶联受体(GPCRs)的新分子尤为重要。越来越多的体外和体内研究表明，GPCRs之间的相互作用改变了它们的药理特征和运输，甚至将它们的耦合切换到不同的细胞内信号通路。此外，在神经科学领域，考虑细胞的细胞背景(即神经元类型)是高度相关的，因为发生在神经元和神经胶质细胞中的独特药物反应。Originus Inc.可以通过使用密歇根大学独家授权的名为表面转染和表达协议(STEP)的专利固相细胞转染技术，为开发更复杂的脑GPCR筛查平台做出贡献，以解决所有上述问题。拟议的新的高密度STEP平台将通过在神经元背景下同时比较小分子对多个大脑GPCR的影响，在提高屏幕的效率和经济性的同时增强信息深度。此外，这个新的平台可以被开发来同时监测每个个体或多个大脑GPCR的几个信号通路的激活。在大脑中表达的大多数GPCRs在健康的心理功能和药物治疗精神功能障碍方面具有潜在的意义，包括精神分裂症、焦虑、抑郁和进食相关的障碍。在这项提案的第一阶段，我们将重点关注一些与神经相关的靶点，包括黑素皮质素系统、食欲素系统、大麻系统和多巴胺能系统。高密度阶跃平台将针对96孔微孔板格式进行优化，但每孔包含36个单独的转染点，导致每个板上有3456个单独的数据点。每个转染点都会表达单独的或“生理相关”的脑GPCRs组合。第一个原型将使用钙通量读数，而第二个原型将允许同时筛选四种不同的报告基因分析。我们计划研究不同GPCRs在两种不同细胞背景下的激活反应，并比较该化合物在HTS常用细胞系和神经细胞系中的药理学特征。在第二阶段，我们计划测试更多基于它们在神经回路中的共同表达的GPCRs组合，以确定在人群中发现的高频等位基因变异的特征，通过RNAi功能丧失来分析特定的细胞内途径，并通过高含量分析转向亚细胞成像。公共卫生相关性尽管目前正在研发的新药有望降低精神疾病的人力和经济成本，但具有新作用机制的治疗大脑功能障碍的药物最近获得的批准非常有限。该项目的最终目标是开发“智能”药物发现平台，使人们能够更好地了解分子通路、细胞活动以及最终体内神经元功能之间的复杂相互关系，从而能够合理地针对复杂的精神疾病进行治疗。

DESCRIPTION (provided by applicant): Recent advances in genomics and proteomics have produced rapid changes in drug discovery, increasing the speed of the High Throughput Screening (HTS) methods by using simple assays on isolated protein targets but sacrificing depth of information and making decisions difficult as to which compounds to pursue in the pipeline. Thus, the need for smarter screening platforms is being recognized, especially platforms that emphasize Cellular Systems Biology. More sophisticated screening strategies are particularly important for discovering new molecules that target G-protein Coupled Receptors (GPCRs). A growing number of studies in vitro and in vivo have shown interactions between GPCRs that modify their pharmacological profile and trafficking, or even switch their coupling to different intracellular signaling pathways. Moreover, in the field of Neuroscience it is highly relevant to consider the cellular background of the cells (i.e. neuronal type) because of unique drug responses that occur in neurons and glia. Originus Inc. can contribute to the development of more sophisticated screening platforms for brain GPCRs that address all of the above considerations, by using a proprietary solid phase cell transfection technology termed Surface Transfection and Expression Protocol (STEP) exclusively licensed from the University of Michigan. The proposed new High-Density STEP platform will increase the efficiency and economy of the screens while enhancing the depth of information by comparing the effects of small molecules on multiple brain GPCRs simultaneously and in a neuronal background. Moreover, this new platform can be developed to monitor the activation of several signaling pathways for each individual or multiplexed brain GPCRs at the same time. Most GPCRs expressed in brain have potential significance in healthy mental function and in pharmaceutical treatment of mental dysfunction, including schizophrenia, anxiety, depression and feeding- related disorders. We will focus during Phase I of this proposal on some of the neurally relevant targets, including the melanocortin system, the orexin system, the cannabinoid system, and the dopaminergic system. The High-Density STEP platforms will be optimized for a 96-well microplate format but containing 36 individual transfection spots per well, resulting in 3,456 individual data-points per plate. Each transfection spot will express individual or "physiological relevant" combinations of brain GPCRs. The first prototype will use calcium flux readout, while the second prototype will allow the simultaneous screening of four different reporter gene assays. We plan to study the activation responses of the different GPCRs in two different cellular backgrounds and compare the compound's pharmacological profiles in cell lines commonly used in HTS and neuronal cell lines. During Phase II we plan to test more GPCR's combinations based on their co-expression in neural circuits, to characterize allelic variants found in high frequency in populations, to analyze specific intracellular pathways by RNAi loss-of-function, and to move to subcellular imaging via High Content Analysis. PUBLIC HEALTH RELEVANCE Although new medicines today in the research and development pipeline offer hope of reducing the human and economic costs of mental disorders, approvals of drugs with novel mechanisms of action for brain dysfunction have been recently very limited. The ultimate goal of this project is the development of "smart" drug discovery platforms that allow a better understanding of the complex interrelationships of molecular pathways, cellular activities and ultimately in vivo neuronal function to enable therapies rationally aimed at complex mental diseases.