Small Molecule Ligand Discovery for Sleep Cycle Disorders

描述(申请人提供)：大脑的中央昼夜节律调节器，视交叉上核(SCN)，与睡眠障碍的病理有关。睡眠巩固的恶化，如不适当或零碎的睡眠，随着年龄或痴呆症的增加而增加，并与昼夜节律信号幅度的减弱有关。一个主要原因被认为是单个SCN核之间失去同步性。一种改变单个振荡器的相位以更好地同步SCN的药物治疗预计将增加昼夜节律信号的幅度，并在睡眠治疗和心理健康方面有强大的好处。BMal1是生物钟中的一种核心转录因子，在人体几乎所有细胞中都有表达。某些孤儿受体是潜在的药物靶点，尚未在药理学水平上确定其特征，它们与BMAL1启动子相互作用。这些受体中的1个主要定位于大脑，在SCN和松果体中高表达，预计能对能够穿越血脑屏障的亲脂小分子产生反应。因此，该受体的配体将是通过诱导或抑制BMAL1来改变SCN输出的相位并使单个SCN核的信号同步的候选者。为了鉴定这个靶点的药理潜力，并启动一个长期的药物发现计划，我们计划鉴定和鉴定小分子配体。这项第一阶段建议的具体目标是：(1)通过筛选20,000+个化合物的小分子文库，鉴定和确认在基于细胞和无细胞分析中都有效的HITS；(2)通过额外的化合物获取和筛选周期，识别包括激动剂和拮抗剂在内的相对选择性的配体；以及(3)表征细胞培养中可以监测基因表达的昼夜周期或其他昼夜依赖性变化的配体的活性。这些目标的成功完成将为在第二阶段疾病动物模型中测试先导化合物的重点开发奠定基础。与公共卫生的相关性。失眠和睡眠障碍会导致职业伤害、心脏病和精神疾病。身体内部生物钟与环境之间失去同步，或身体正常昼夜节律的幅度降低，是导致睡眠障碍的主要原因。目前更好地同步或增强人体内部时钟功能的治疗方法效果有限。一种有效调节昼夜节律的新型药物将在治疗时差、轮班工作引起的睡眠障碍以及因抑郁症、阿尔茨海默氏症和衰老而导致的各种形式的失眠方面具有重大价值，这些疾病每年影响着1000多万美国人。

DESCRIPTION (provided by applicant): The central circadian regulator of the brain, the suprachiasmatic nucleus (SCN), has been implicated in the pathology of sleep disorders. Deterioration of sleep consolidation, such as inappropriate or fragmented sleep, increases with age or dementia and is correlated with diminished amplitude of circadian signaling. A major cause is presumed to be loss of synchrony among individual SCN nuclei. A pharmacological treatment that shifts the phase of individual oscillators to better synchronize the SCN is predicted to increase the amplitude of circadian signaling and to have a powerful benefit in sleep therapy and mental health. BMAL1 is a central transcription factor within the circadian clock and is expressed in virtually all cells of the body. Certain orphan receptors, potential drug targets that have not been characterized at a pharmacological level, interact with the BMAL1 promoter. 1 of these receptors, localized predominantly in the brain and highly expressed in the SCN and pineal gland, is predicted to respond to lipophilic small molecules capable of crossing the blood-brain barrier. Ligands to this receptor would therefore be candidates to shift the phase of SCN output and to synchronize signaling of individual SCN nuclei by induction or suppression of BMAL1. To characterize the pharmacological potential of this target and initiate a long-term program of drug discovery, we plan to identify and characterize small molecule ligands. The specific aims for this Phase I proposal are: (1) to identify and confirm hits that are active in both cell-based and cell-free assays by screening a small molecule library of 20,000+ compounds; (2) identify relatively selective ligands, including both agonists and antagonists, by additional cycles of compound acquisition and screening; and (3) characterize ligand activity in cell culture where circadian cycle or other circadiandependent changes in gene expression can be monitored. Successful completion of these aims will set the stage for focused development of lead compounds for testing in animal models of disease in Phase II. Relevance to Public Health. Insomnia and sleep disturbance contribute to occupational injuries, heart disease, and mental illness. Loss of synchrony between the body's internal clock and the environment, or a reduction in the amplitude of the body's normal circadian rhythm, is a major cause of sleep disorders. Current therapeutic approaches to better synchronize or enhance the function of the body's internal clock have limited effectiveness. A novel class of drug that effectively regulates circadian rhythm will have major value in treatment of jet lag, sleep disorders of shift work, and forms of insomnia due to depression, Alzheimer's disease, and aging that affect more than 10 million Americans each year.