FUNCTIONAL PROBES FOR BRAIN HISTAMINE H1 RECEPTORS

描述（由申请人提供）：本申请旨在设计和合成新型苯胺四联灵（PAT）化合物，作为生物化学探针和药物，靶向组胺h1型G蛋白偶联受体（gpcr），调节神经精神疾病中脑儿茶酚胺神经递质合成。初步结果表明，PATs是一种功能选择性配体，可以区分和选择性激活脑H1受体，这些受体与肌醇磷酸（IP）和cAMP偶联，从而调节酪氨酸羟化酶（TH）活性和儿茶酚胺合成。这种配体导向的功能异质性被提出用于其他gpcr，然而，缺乏选择性药物化学探针来绘制构成差异信号传导分子基础的配体-受体相互作用的分子决定因素。同样，由于缺乏能进入大脑的有效的、功能选择性的激动剂配体，脑H1受体未被开发为心理和神经治疗靶点。我们开发了立体选择性H1探针，[3H]-(-)-反式pat，可以推定区分激活cAMP信号的H1受体子集。合成34个PAT来描述PAT-H1药效团-特异性的PAT立体、亲脂性和H1受体差异结合和信号传导的电子化学决定因素。在放射性受体研究中，利用重组人H1受体检测了pat与H1活性位点的分子相互作用，这些受体具有13个氨基酸点突变，假设这些氨基酸是PAT-H1结合的分子决定因素。我们验证了一个配体导向的功能异质性假说，即PATs的立体化学和其他结构参数决定了H1的功能选择性结合和IP与cAMP信号的激活，以刺激哺乳动物大脑中TH和儿茶酚胺的合成。利用CoMFA 3DQSAR和药效基团作图将结构-活性数据进行关联，建立用于PAT配体对接研究的H1受体模型。结果将表明参与PAT结合的氨基酸和H1受体三维结构的推断。QSAR模型迭代改进，以预测H1功能选择性结合和信号传导的PAT化学。由于大多数不利的H1介导效应是通过IP信号传导进行的，因此选择性增强H1 cAMP信号传导的pat将为利用脑H1受体作为神经精神疾病的药物靶点提供机制基础。

DESCRIPTION (provided by applicant): This application is to design and synthesize novel phenylaminotetralin (PAT) compounds as biochemical probes and drugs that target histamine H1-type G protein-coupled receptors (GPCRs) to modulate brain catecholamine neurotransmitter synthesis in neuropsychiatric disorders. Preliminary results suggest PATs are functionally selective ligands that can distinguish and selectively activate brain H1 receptors that couple to the inositol phosphates (IP) vs. cAMP intracellular signaling pathways to modulate tyrosine hydroxylase (TH) activity and catecholamine synthesis. Such ligand-directed functional heterogeneity is proposed for other GPCRs, however, there is a paucity of selective medicinal chemical probes to map the molecular determinants of ligand-receptor interactions that form the molecular basis of differential signaling. Likewise, brain H1 receptors are unexploited as psycho- and neuro-therapeutic targets due to lack of potent, functionally selective agonist ligands that can enter into brain. We developed the stereoselective H1 probe, [3H]-(-)-trans-PAT, that putatively distinguishes the subset of H1 receptors that activate cAMP signaling. Syntheses of 34 PATs is proposed to delineate the PAT-H1 pharmacophore - the specific PAT steric, lipophilic, and electronic chemical determinants for H1 receptor differential binding and signaling. Molecular interaction of PATs with the H1 active site is examined in radioreceptor studies using recombinant human H1 receptors with point mutatations of 13 amino acids hypothesized to be molecular determinants for PAT-H1 binding. We test a hypothesis of ligand-directed functional heterogeneity, i.e., stereochemical and other structural parameters of PATs determines H1 functionally selective binding and activation of IP vs. cAMP signaling to stimulate TH and catecholamine synthesis in mammalian brain. Structure-activity data is correlated using CoMFA 3DQSAR and pharmacophore mapping to develop an H1 receptor model for PAT ligand docking studies. Results will indicate amino acids involved in PAT binding and inferences of H1 receptor 3D structure. QSAR models are iteratively refined to predict PAT chemistry for H1 functionally selective binding and signaling. As most untoward H1-mediated effects proceed via IP signaling, PATs that selectively enhance H1 cAMP signaling will provide a mechanistic basis for exploiting brain H1 receptors as drug targets in neuropsychiatric diseases.