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）：离子型谷氨酸受体控制多种正常神经元过程，包括学习和记忆。这些重要的神经递质受体的激活涉及许多神经退行性疾病，特别是中风和癫痫。此外，增强谷氨酸受体AMPA亚型谷氨酸活性的药物（变构调节剂）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受体与谷氨酸结合的结构域（S1 S2结构域）可以作为细菌中的可溶性蛋白质产生，并使用多种高分辨率生物物理方法进行研究。S1 S2结构域已被证明是研究与AMPA受体相互作用的药物的极好模型系统，因为至少在激动剂结合位点，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。蛋白质是单体低于6 mM，但变构调节剂可以促进S1 S2结构域的二聚化，同时阻断脱敏和减缓膜结合蛋白的失活速率。我们已经确定了一个AMPA受体结合结构域（GluR 2 S1 S2）与六种不同的变构激活剂的晶体结构，并研究了一些配合物使用NMR光谱。考虑到在所有结构中产生的结合相互作用，可以在二聚体界面处限定相对大的结合表面。尽管对变构调节剂的功能作用进行了大量的研究，但对结合机制、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知之甚少。我们建议使用X-射线晶体学，NMR光谱，等温滴定量热法，分析ultracenthegation，结合全细胞记录详细定义的结合相互作用。我们的目标是了解药物如何与该表面结合（单体与二聚体，控制亚位点特异性的是什么），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，我们预计应该比目前可用的药物具有更高的亲和力和特异性。我们相信，详细研究这些药物与AMPA受体的相互作用，在本申请中描述的将导致新的线索，设计有效的药物，以提高认知。 公共卫生相关性：AMPA受体介导中枢神经系统中大部分快速兴奋性突触传递。AMPA受体活性的增强已被证明有益于增加认知，使得放大谷氨酸（变构激活剂）作用的药物可有效治疗阿尔茨海默病和其他神经障碍。本申请旨在了解变构激活剂的结合位点，目的是定义这些药物的作用机制和功能效应的结构相关性。