Allosteric Modulation of Neuronal Nicotinic Acetylcholine Receptors

描述(申请人提供)：我们研究神经元烟碱型乙酰胆碱受体(NAChRs)的变构调节。这些配基门控离子通道是尼古丁成瘾的场所，并与广泛的其他神经疾病有关。随着人们对nAChRs的更好的理解和具有这种药理特征的新化合物的发现，nAChRs的变构调节变得越来越重要。一类模型调节化合物的结合位点是已知的，并且已经确定了将调节剂结合信息转化为通道活性的一些分子决定因素。在以前工作的基础上，我们现在建议进一步完善我们对分子内信号转导中涉及的一个亚结构的运动以及调节子位置特异性的分子决定因素的理解。此外，关于通道门控有效性的问题将从与激动剂位置相关的调制器位置的最佳数量和排列以及疏水残基在细胞外结构域核心中的作用来解决。这些研究将通过宏观电压钳记录以及化学修饰分析，对带有点突变或串联亚单位的表达受体进行药理学表征。该项目还包括对新的调节剂类似物进行有针对性的结构-活性关系研究。在某些情况下，为了支持这些主要目标，我们将通过单通道录制进一步探索调制机制。我们的工作是创新的，因为我们通过占据两个激动剂结合位点来挑战nAChRs激活的范式。我们正在研究最近发现的nAChR配体结合位点，我们提出的工作将大大加强nAChR变构调节剂合理设计的基础，nAChR变构调节剂是一类可能的临床应用药物。

DESCRIPTION (provided by applicant): We study allosteric modulation of neuronal nicotinic acetylcholine receptors (nAChRs). These ligand-gated ion channels are the seat of nicotine addiction and are implicated in a wide range of other neurological disorders. Allosteric modulation of nAChRs is growing in importance as it becomes better understood and as novel compounds with this pharmacological profile are identified. The binding sites for a class of model modulatory compounds, quite specific for one subtype of neuronal nAChR, are known, and some molecular determinants of transducing modulator binding information into channel activity have been identified. Building on this previous work, we now propose to further refine our understanding of the movement of one sub- structure involved in intra-molecular signal transduction and of the molecular determinants of modulator site specificity. In addition, questions about channel gating efficacy will be addressed in terms of the optimal number and arrangement of modulator sites relative to agonist sites and the role of hydrophobic residues in the extracellular domain core. These studies will employ pharmacological characterization of expressed receptors with point mutations or concatenated subunits by macroscopic voltage-clamp recordings, as well as chemical modification analyses. The project also includes a targeted structure-activity relationship study with new modulator analogues. In some cases, to support these primary aims, we will explore the modulation mechanisms further by single-channel recordings. Our work is innovative because we are challenging the paradigm of activation of nAChRs by occupying two agonist binding sites. We are studying a recently identified nAChR ligand binding site, and the work we propose stands to substantially strengthen the foundation for rational design of nAChR allosteric modulators, a drug class with possible clinical applications.