Mechanism and physiology of NMDA receptor desensitization

NMDA受体脱敏机制和生理学

基本信息

批准号：
9765414
负责人：
Kelvin Chan
金额：
$ 3.44万
依托单位：
STATE UNIVERSITY NEW YORK STONY BROOK
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-09-27 至 2021-09-26
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9765414
关键词：
AMPA Receptors Acute Address Adopted Affect Agonist Binding Biophysical Process Brain Brain Diseases Charge Chronic Clinical Cysteine Data Development Electrophysiology (science)Event Frequencies Gated Ion Channel Glutamate Receptor Glutamates Glycine Hippocampus (Brain)Image Individual Ion Channel Ion Channel Gating Kainic Acid Receptors Kinetics Knowledge Learning Ligand Binding Domain Ligands Light Long-Term Depression Long-Term Potentiation Mediating Memory Mental disorders Modality Molecular Conformation Mus Mutation N-Methyl-D-Aspartate Receptors N-Methylaspartate NMDA receptor A1 Nervous system structure Neurotransmitters Pathway interactions Patients Physiological Physiology Play Process Property Recombinants Recovery Role Schizophrenia Signal Transduction Site Slice Structure Synapses Synaptic plasticity System Techniques Technology Testing Transfection Transmembrane Domain base crosslink desensitization dimer experimental study gene gun glutamatergic signaling hippocampal pyramidal neuron insight mutant neuropsychiatric disorder neuropsychiatry novel novel therapeutics patch clamp protein function receptor tool two-photon unnatural amino acids

项目摘要

PROJECT SUMMARY NMDA receptor hypofunction has been implicated in neuropsychiatric disorders such as schizophrenia, a disabling mental disorder that affects over 2.2 million patients in the US. One modality for NMDA receptor hypofunction is aberrant gating, the process where the receptor converts glutamate binding into opening of the associated ion channel. One pathway to regulate hypofunction is NMDA receptor desensitization, a gating configuration where the receptor is ligand-bound, but the ion channel is non-conducting. However, its physiological and mechanistic basis is poorly defined in part because of the lack of tools to study it. In this proposal I will take advantage of new tools – single site mutations that selectively alter specific features of NMDA receptor desensitization recently discovered in the Wollmuth lab – as well as cutting edge technologies to address the mechanism and physiology of NMDA receptor desensitization. Whereas desensitization in non-NMDA receptors depends almost exclusively on the rearrangement of the ligand-binding domain (LBD) dimer interface, such a mechanism is less significant in NMDA receptors and all domains, most notably the transmembrane domain (TMD), have been implicated in NMDA receptor desensitization. In Aim 1, I will test the general hypothesis that the mechanism of NMDA receptor desensitization is fundamentally different from that of non-NMDA receptors, depending strongly on the conformation of the ion channel. To test this hypothesis, I will take advantage of newly identified single-site mutations, patch clamp electrophysiology as well as techniques to regulate the subunit composition of NMDA receptors and light-activated unnatural amino acids. These experiments will help define the structural mechanisms that govern NMDA receptor desensitization, aiding in the development of novel therapeutics that can selectively modulate NMDA receptor activity by specifically targeting desensitization. In Aim 2, I will test the hypothesis that NMDA receptor desensitization leads to decreased excitatory signaling at synapses during high activity. Indeed, my preliminary data show that fast applications of glutamate caused a higher degree of current decay in these mutants, suggesting a potential role of desensitization in NMDA hypofunction. To test this hypothesis more rigorously, I will express mutant NMDA receptors that have altered desensitization properties in organotypic hippocampal slice cultures to address how they change synaptic dynamics including Ca2+ influx and synaptic plasticity. These experiments will address how NMDA receptor desensitization contributes to synaptic physiology. The information gained by the experiments in this proposal will provide insight into the mechanism of NMDA receptor desensitization and its role in synaptic dynamics. My experiments will aid in the development of novel therapeutics that selectively modulates NMDA receptor activity by specifically targeting desensitization.

项目概要 NMDA 受体功能低下与精神分裂症等神经精神疾病有关。影响美国超过 220 万患者的致残性精神障碍 NMDA 受体的一种治疗方式。功能减退是门控异常，即受体将谷氨酸结合转化为开放的过程调节相关离子通道功能减退的一种途径是 NMDA 受体脱敏，这是一种门控构型，其中受体与配体结合，但离子通道不导电。生理学和机制基础的定义不明确，部分原因是缺乏研究它的工具。提案我将利用新工具——选择性改变特定特征的单位点突变 Wollmuth 实验室最近发现了 NMDA 受体脱敏——也是尖端技术解决 NMDA 受体脱敏机制和生理学的技术。尽管非 NMDA 受体的脱敏几乎完全取决于重排配体结合域 (LBD) 二聚体界面的作用，这种机制在 NMDA 受体中不太重要所有结构域，尤其是跨膜结构域 (TMD)，都与 NMDA 受体有关在目标 1 中，我将检验 NMDA 受体机制的一般假设。脱敏与非 NMDA 受体的脱敏有根本不同，很大程度上取决于为了检验这个假设，我将利用新识别的单位点。突变、膜片钳电生理学以及调节亚基组成的技术 NMDA 受体和光激活非天然酸氨基酸这些实验将有助于确定结构。控制 NMDA 受体脱敏的机制，有助于开发新疗法可以通过特异性靶向脱敏来选择性调节 NMDA 受体活性。在目标 2 中，我将检验 NMDA 受体脱敏导致兴奋性信号传导减少的假设事实上，我的初步数据表明，谷氨酸的快速应用会导致突触的高活性。这些突变体的电流衰减程度较高，表明 NMDA 脱敏的潜在作用为了更严格地检验这个假设，我将表达具有突变的 NMDA 受体。改变器官型海马切片培养物的脱敏特性，以解决它们如何变化突触动力学，包括 Ca2+ 流入和突触可塑性。这些实验将解决 NMDA 如何发挥作用。受体脱敏有助于突触生理学。通过本提案中的实验获得的信息将有助于深入了解该机制 NMDA 受体脱敏及其在突触动力学中的作用我的实验将有助于开发通过特异性调节 NMDA 受体活性的治疗小说针对性脱敏。