High-throughput behavior-based dopaminergic drug discovery in the zebrafish

描述（由申请人提供）：从历史上看，小分子一直是解剖神经系统功能不可或缺的工具。然而，很难发现新的精神药物并确定它们影响行为的机制。在这里，我建议发现新的神经活性化合物，影响多巴胺介导的行为在斑马鱼。这些研究旨在加快神经活性药物发现的步伐，并为理解脊椎动物行为提供小分子工具。抑郁症、焦虑症和精神分裂症等精神疾病是广泛存在的毁灭性疾病。尽管需要改进精神药物，但精神疾病和其他神经系统疾病的药物发现成功率低于其他治疗领域。神经系统无与伦比的复杂性无疑有助于识别具有可接受的毒性和副作用特征的新型有效神经活性药物的挑战。为了满足对新型神经活性药物的巨大未满足的需求，开发新的神经活性药物发现方法至关重要。由于神经系统的复杂性很可能在短期内排除对疾病病理的完全机械理解，因此在缺乏机械理解的情况下有效的药物发现方法将具有特别的价值。识别新的神经活性化学物质是开发精神病药物的重要第一步。但是，由于缺乏对导致精神疾病的生化机制的详细了解，如何发现新的神经活性药物？遗传学和药理学是理解神经系统中分子信号通路的两种主要方法。然而，传统的药物遗传学方法严重偏向于系统生物学的基因组方面。全基因组应用于研究单一药物的作用正变得越来越普遍。相比之下，对化学物质如何影响特定基因型和表型的大规模分析的发展要慢得多。一个原因是基于表型的化学筛选对于大多数模式生物来说并不实用或成本效益不高。考虑到通过低通量和非系统方法发现的小分子的影响，系统的基于行为的化学筛选可能会提供很多东西。基于斑马鱼表型的化学筛选是一种非传统的方法，用于识别新的生物活性化合物。具有有价值的神经活性的未表征的化合物很可能已经存在于现代化学图书馆的威尔斯井中。然而，体外测定过于简单，并且哺乳动物中的表型测定的通量太低，不能有效地鉴定这些有价值的分子。与较大的脊椎动物不同，斑马鱼足够小，可以很容易地排列在96孔板的单个威尔斯孔中，沿着化学库中的化学物质排列。因此，基于行为的斑马鱼化学筛选提供了系统评估化学物质如何影响完整脊椎动物神经系统的机会。多巴胺修饰化合物是重要的治疗药物和研究工具。然而，迄今为止，只有少数几类具有数十年历史的多巴胺修饰药物被发现。该提案的一个主要目标是利用斑马鱼中DA介导的行为作为生物测定来鉴定新的神经活性药物和靶标。DA信号传导的良好表征的行为模型已经在小鼠和其他模型生物体中得到良好表征，并且已经证明对于鉴定已知的抗精神病药物具有高预测有效性。因此，在斑马鱼中修饰DA信号传导的新化合物也可以具有治疗人类精神分裂症、躁狂症和其他精神疾病的症状的治疗活性。在建议的指导研究期间，我的目标是获得精神活性药物发现和开发的各个方面的经验。这些技能将使我能够将我的初步发现发展成为化学生物学和精神药物发现前沿的有效和可持续的研究计划。鉴于行为表型和神经活性药物在我们理解和治疗精神疾病中所起的历史作用，我希望在斑马鱼中进行系统的基于行为的化学筛选可能会加快神经活性药物发现的步伐，并提高我们对大脑和行为的理解。最终，我希望这项工作将为治疗精神疾病和其他神经系统疾病带来新的治疗方法。 公共卫生相关性：从历史上看，小分子一直是剖析神经系统功能的有力工具：多巴胺（DA）修饰化合物彻底改变了我们对精神疾病的理解和治疗。然而，一个系统的识别化合物，修改DA介导的行为一直是不可能的。在这里，我们建议利用新开发的高通量行为为基础的化学筛选策略在斑马鱼中识别和表征新的DA修饰化合物。这些努力可能会加快神经活性药物发现的步伐。

DESCRIPTION (provided by applicant): Historically, small molecules have been indispensable tools for dissecting nervous system function. However, it has been difficult to discover novel psychotropic compounds and determine the mechanisms by which they affect behavior. Here, I propose to discover new neuroactive compounds that affect dopamine-mediated behaviors in the zebrafish. These studies aim to accelerate the pace of neuroactive drug discovery and provide small-molecule tools for understanding vertebrate behavior. Psychiatric disorders such as depression, anxiety and schizophrenia are widespread and devastating illnesses. Despite the need for improved psychiatric medicines, drug discovery success rates for psychiatric illnesses and other disorders of the nervous system are lower than for other therapeutic areas. The unparalleled complexity of the nervous system undoubtedly contributes to the challenge of identifying novel and effective neuroactive drugs with acceptable toxicity and side effect profiles. To meet the vast unmet need for novel neuroactive drugs, it will be essential to develop new approaches to neuroactive drug discovery. Because the complexity of nervous system is likely to preclude complete mechanistic understanding of disease pathology in the near term, drug discovery approaches that can be effective in the absence of mechanistic understanding will be of particular value. Identifying novel neuroactive chemicals is an important first step toward developing psychiatric medicines. But, lacking a detailed understanding of the biochemical mechanisms that cause psychiatric disease, how can novel neuroactive drugs be discovered? Genetics and pharmacology are the two dominant approaches for understanding molecular signaling pathways in the nervous system. However, traditional pharmacogenetic approaches are heavily biased towards the genome side of systems biology. Genome-wide applications for investigating the effects of single drugs are becoming more common. By contrast, large-scale analyses of how chemicals affect specific genotypes and phenotypes have been much slower to develop. One reason is that phenotype based chemical screens have not been practical or cost-effective using most model organisms. Given the impact of small molecules that were discovered via low throughput and non-systematic approaches, it is likely that systematic behavior-based chemical screening has much to offer. Phenotype based chemical screens in the zebrafish are a non-conventional approach for identifying novel bioactive compounds. It is likely that uncharacterized compounds with valuable neuroactive activity already exist in the wells of modern chemical libraries. However, in vitro assays are too simplistic, and phenotypic assays in mammals too low throughput, to efficiently identify these valuable molecules. Unlike larger vertebrates, zebrafish are small enough to be easily arrayed in the individual wells of a 96-well plate along with chemicals from a chemical library. As a result, behavior-based chemical screens in the zebrafish provide the opportunity to systematically assess how chemicals affect the intact vertebrate nervous system. Dopamine (DA) modifying compounds are important therapeutic drugs and useful research tools. However, only a few bioactive classes of decades-old dopamine-modifying drugs have been identified to date. A main goal of this proposal is to utilize DA-mediated behaviors in the zebrafish as bioassays to identify novel neuroactive drugs and targets. Well-characterized behavioral models of DA signaling have been well- characterized in mice and other model organisms and have been proven to have high predictive validity for identifying known antipsychotic drugs. Thus, novel compounds that modify DA signaling in the zebrafish may also have therapeutic activity for treating the symptoms of schizophrenia, mania and other psychiatric diseases in humans. During the proposed period of mentored research, I aim to gain experience in all aspects of psychoactive drug discovery and development. These skills will enable me to develop my initial findings into an effective and sustainable research program on the leading edge of chemical biology and psychiatric drug discovery. Given the historical roles that behavioral phenotypes and neuroactive drugs have played in our understanding and treatment of mental illness, I expect systematic behavior-based chemical screening in the zebrafish may accelerate the pace neuroactive drug discovery and improve our understanding of the brain and behavior. Eventually, I hope that this work will lead to novel therapeutic approaches for treating mental illness and other neurological disorders. PUBLIC HEALTH RELEVANCE: Historically, small molecules have been powerful tools for dissecting the functions of the nervous system: dopamine (DA) modifying compounds have revolutionized our understanding and treatment of mental illnesses. However, a systematic identification of compounds that modify DA mediated behaviors has not been possible. Here, we propose to utilize newly developed high-throughput behavior based chemical screening strategies in zebrafish to identify and characterize novel DA modifying compounds. These efforts may accelerate the pace of neuroactive drug discovery.