Allosteric Modulators of Glutamate Receptors

谷氨酸受体的变构调节剂

• 批准号: 7918782
• 负责人: ROBERT E OSWALD
• 金额: $ 19.06万
• 依托单位: CORNELL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2012-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7918782
• 关键词: AMPA Receptors; Affinity; Agonist; Alzheimer' s Disease; Amyotrophic Lateral Sclerosis; Bacteria; Binding; Binding Proteins; Binding Sites; Biological Models; Calorimetry; Cells; Clinical Trials; Cognition; Complex; Complication; Crystallography; Data; Dimerization; Diuretics; Drug Binding Site; Drug Design; Drug Interactions; Drug Prescriptions; Epilepsy; Free Energy; Glutamate Receptor; Glutamates; Goals; Huntington Disease; Ischemic Brain Injury; Lead; Learning; Length; Ligands; Mediating; Membrane; Memory; Methods; Modification; NMR Spectroscopy; Nervous system structure; Neuraxis; Neurodegenerative Disorders; Neurologic; Neurons; Neurotransmitter Receptor; Parents; Parkinson Disease; Pharmaceutical Preparations; Play; Process; Proteins; RNA Splicing; Resolution; Role; Site; Specificity; Stroke; Structure; Surface; Synaptic Transmission; Techniques; Testing; Therapeutic; Titrations; United States; Whole-Cell Recordings; Work; X-Ray Crystallography; analytical ultracentrifugation; aniracetam; cognitive function; conformational conversion; desensitization; design; dietary supplements; dimer; drug testing; functional outcomes; high throughput screening; improved; interest; kainate; monomer; nervous system disorder; public health relevance; receptor; receptor binding; stoichiometry; therapeutic target; thiazide

DESCRIPTION (provided by applicant): Ionotropic glutamate receptors control a wide variety of normal neuronal processes including learning and memory. Activation of these important neurotransmitter receptors is involved in a number of neurodegenerative diseases, notably stroke and epilepsy. In addition, drugs that enhance the activity of glutamate at the AMPA subtype of glutamate receptors (allosteric modulators) have been shown to improve cognition and may have benefits in neurodegenerative diseases such as Alzheimer's disease. The domain of AMPA receptors that binds glutamate (S1S2 domain) can be produced as a soluble protein in bacteria and studied with a variety of high-resolution biophysical methods. The S1S2 domain has been shown to be an excellent model system for the study of drugs that interact with AMPA receptors in that, at least at the agonist binding site, the binding affinity is the same as the membrane-bound, full-length tetrameric protein and the conformational transitions upon binding seem to be similar as well. The protein is monomeric below 6 mM, but allosteric modulators can promote dimerization of the S1S2 domain, while blocking desensitization and slowing the rate of deactivation in the membrane-bound protein. We have determined the crystal structure of one AMPA receptor-binding domain (GluR2 S1S2) with six different allosteric activators and studied some of the complexes using NMR spectroscopy. Considering the binding interactions made in all of the structures, a relatively large binding surface at the dimer interface can be defined. Despite considerable work on the functional effects of allosteric modulators, very little is known about the mechanism of binding, the structural interactions that lead to a functional outcome, and, in some cases, even the stoichiometry of binding. We propose to define the binding interaction in detail using X-ray crystallography, NMR spectroscopy, isothermal titration calorimetry, and analytical ultracentrifugation, in conjunction with whole cell recording. The goal will be to understand how drugs bind to this surface (monomer vs. dimer, what controls the subsite specificity), how to amplify affinity, how binding interactions are related to functional outcomes, and how to provide as much specificity as possible at this site. In addition, we have designed and are synthesizing dimeric forms of allosteric activators that we anticipate should bind with higher affinity and specificity than currently available drugs. We believe that detailed studies of the interaction of these drugs with AMPA receptors described in this application will lead to new clues as to the design of effective drugs for enhancing cognition. PUBLIC HEALTH RELEVANCE: AMPA receptors mediate the majority of fast excitatory synaptic transmission in the central nervous system. Enhancement of the activity of AMPA receptors has been shown to be beneficial in increasing cognition, such that drugs that amplify the effect of glutamate (allosteric activators) may be effective in treatment of Alzheimer's disease and other neurological disorders. This application is targeted toward understanding the binding site for allosteric activators with the goal of defining the mechanism of action and the structural correlates of the functional effects of these drugs.

描述（由申请人提供）：嗜离子性谷氨酸受体控制各种正常的神经元过程，包括学习和记忆。这些重要的神经递质受体的激活与许多神经退行性疾病有关，特别是中风和癫痫。此外，增强谷氨酸受体AMPA亚型（变构调节剂）谷氨酸活性的药物已被证明可以改善认知，并可能对阿尔茨海默病等神经退行性疾病有益。AMPA受体结合谷氨酸的结构域（S1S2结构域）可以作为一种可溶性蛋白在细菌中产生，并通过各种高分辨率的生物物理方法进行研究。S1S2结构域已被证明是研究与AMPA受体相互作用的药物的一个很好的模型系统，因为至少在激动剂结合位点，其结合亲和力与膜结合的全长四聚体蛋白相同，并且结合时的构象转变似乎也相似。该蛋白是小于6 mM的单体，但变构调节剂可以促进S1S2结构域的二聚化，同时阻断脱敏并减缓膜结合蛋白的失活速度。我们用六种不同的变构活化剂确定了一种AMPA受体结合域（GluR2 S1S2）的晶体结构，并利用核磁共振光谱研究了其中的一些配合物。考虑到所有结构中的结合相互作用，可以在二聚体界面处定义一个较大的结合面。尽管对变构调节剂的功能效应进行了大量的研究，但对结合的机制、导致功能结果的结构相互作用，以及在某些情况下，甚至结合的化学计量学都知之甚少。我们建议使用x射线晶体学，核磁共振光谱，等温滴定量热法和分析超离心，结合全细胞记录来详细定义结合相互作用。目标将是了解药物如何结合到该表面（单体与二聚体，控制亚位点特异性的因素），如何增强亲和力，结合相互作用如何与功能结果相关，以及如何在该位点提供尽可能多的特异性。此外，我们已经设计并正在合成二聚体形式的变构激活剂，我们预计它将比目前可用的药物具有更高的亲和力和特异性。我们相信，对这些药物与本应用中描述的AMPA受体相互作用的详细研究将为设计有效的增强认知的药物提供新的线索。