Structural mechanism and function of endogenous ligands targeting orphan NR4A receptors

 描述（由申请人提供）：核受体（NR）转录因子的NR 4A亚类（Nurr 1、Nur 77和NOR-1）在哺乳动物细胞的许多方面的发育、调节和维持中具有重要作用。 physiology. NR 4A在中枢神经系统（CNS）中特别丰富，并且在中枢神经系统（CNS）中起关键作用。 大脑的发育和维持。靶向NR 4A活性的治疗剂可以在以下方面保持效用： 帕金森病（在美国有100万人）和精神分裂症（300万人以上）的治疗 美国的百万人）。NR 4A还在骨骼肌、脂肪、心血管、 肾和肝组织，包括在发炎疾病组织中的异常表达，提示NR 4A调节剂可用于治疗炎症、关节炎、癌症和代谢疾病（dysli）。 Idemia， 肥胖、糖尿病和心血管疾病）。然而，努力探索配位性和drugga- NR 4A的活性已被显著抑制，因为它们被归类为“孤儿”受体。 到目前为止，还没有发现内源性（天然）NR 4A配体，并且据信NR 4A配体 功能独立于结合配体。这种“孤儿”分类部分是基于一种晶体 apoNurr 1的结构，这表明Nurr 1在非孤儿NR用于结合内源性配体的保守配体结合口袋区域内缺乏物理空间。虽然apoNurr 1晶体 结构显示了一个塌陷的配体结合口袋，NMR研究表明该区域在 µs-ms时间尺度，表明扩展的能力。我们的初步工作使用了一系列的结构和 功能方法表明Nurr 1可以结合其推定的LBP中的内源性配体，并且 内源性配体可以影响Nurr 1功能。我们的数据还表明，Nurr 1和Nur 77可能具有 对内源性配体的不同特异性。详细阐述了endo的结构机制和功能， 靶向NR 4A的基因配体将证明这些孤儿受体确实是配体 监管和授权他人使用这些天然化学工具来探索NR 4A在体内的功能。我们提出了一个多学科的方法，结合结构生物学与生物化学，生物物理和细胞测定，以确定配体特异性，结构和功能的影响，和细胞 靶向NR 4A的内源性配体的结果。这些研究的结果将证明NR 4A是真正的配体结合受体。由于具有已知内源性配体的NR是大量当前FDA批准的药物的靶标（估计在2006年为13%），因此该知识将刺激针对帕金森病、精神分裂症和其他人类健康状况的NR 4A药物靶向策略的开发。

 DESCRIPTION (provided by applicant): The NR4A subclass of nuclear receptor (NR) transcription factors (Nurr1, Nur77 and NOR-1) have essential roles in the development, regulation and maintenance of many aspects of mammalian physiology. NR4As are especially abundant in the central nervous system (CNS) and play critical roles in brain development and maintenance. Therapeutics targeting NR4A activity may hold utility in treatment of Parkinson's disease (afflicts 1 million people in the US) and schizophrenia (afflicts >3 million people in the US). The NR4As are also expressed in skeletal muscle, adipose, cardiovascular, kidney and liver tissues, including aberrant expression in inflamed disease tissues, suggesting utility forNR4A modulators to treat inflammation, arthritis, cancer, and metabolic conditions (dysli idemia, obesity, diabetes and cardiovascular disease). However, efforts to probe the ligandability and drugga- bility of the NR4As have been significantly stunted because they are classified as "orphan" receptors. Thus far, no endogenous (natural) NR4A ligands have been discovered, and it is believed the NR4As function independent of binding ligand. This "orphan" classification was made in part based on a crystal structure of apoNurr1, which indicates Nurr1 lacks physical space within the conserved ligand biding pocket region used by nonorphan NRs to bind endogenous ligands. Although the apoNurr1 crystal structure shows a collapsed ligandbinding pocket, NMR studies indicate this region is dynamic on the µs-ms timescale, suggesting the ability to expand. Our preliminary work using an array of structural and functional approaches shows that Nurr1 can bind an endogenous ligand in its putative LBP and that endogenous ligands can affect Nurr1 function. Our data also indicate that Nurr1 and Nur77 may have different specificities for endogenous ligands. Detailing the structural mechanism and function of endo- genous ligands targeting the NR4As will demonstrate these orphan receptors are indeed ligand regulated and empower others to use these natural chemical tools to explore NR4A function in vivo. We propose a multidisciplinary approach combining structural biology with biochemical, biophysical and cellular assays to determine the ligand specificity, structural and functional effects, and cellula outcomes of endogenous ligands targeting the NR4As. Outcomes from these studies would demonstrate that the NR4As are bone fide ligand-binding receptors. Because NRs with known endogenous ligands are targets of significant number of current FDA approved drugs (estimated at 13% in 2006), this knowledge will stimulate the development of NR4A drug targeting strategies for Parkinson's disease, schizophrenia, and other human health conditions.