Astrocytic Control of GABA Inhibition in Epilepsy

星形胶质细胞对癫痫 GABA 抑制的控制

基本信息

批准号：
8839120
负责人：
John R Huguenard
金额：
$ 37.2万
依托单位：
STANFORD UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-09-01 至 2018-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8839120
关键词：
Absence Epilepsy Alanine Amoeba genus Animals Antiepileptic Agents Anxiety Astrocytes Behavior Behavioral Benzodiazepines Binding Sites Biological Assay Brain Cell Nucleus Cells Childhood Data Detection Development Diazepam Binding Inhibitor Disease Disease model Electroencephalography Enzymes Epilepsy Equilibrium Extracellular Space Gelatinase A Generations Genetic Glial Fibrillary Acidic Protein Glucose Glutamates In Situ In Vitro Kinetics Knock-out Ligands Literature Measures Mediating Metabolic Monitor Mus Mutant Strains Mice Neurons Neurophysiology - biologic function Neurotransmitters Organism Pathway Analysis Pathway interactions Peptides Phosphorylation Physiological Play Poisoning Predisposition Process Production Protein Fragment Proteins Reporter Role Scanning Seizures Signal Transduction Site Slice Source Speed Synapses Synaptic Transmission Testing Thalamic structure Therapeutic Therapeutic Intervention Threonine Viral Yeasts brain cell cranium effective therapy extracellular fatty acid metabolism fluorocitrate gamma-Aminobutyric Acid improved in vivo knockout animal lipid metabolism neural circuit neuromechanism neuropsychiatry novel strategies octadecaneuropeptide optogenetics postsynaptic prevent prolyl oligopeptidase promoter public health relevance receptor relating to nervous system research study response secretion process synaptic inhibition therapeutic target uptake

项目摘要

DESCRIPTION (provided by applicant): We have recently shown that naturally occurring neuroactive compounds, endozepines related to the protein Diazepam Binding Inhibitor (DBI) in the brain can mimic the activity of benzodiazepines, which are effective treatments in epilepsy. Benzodiazepines are allosteric modulators of GABAA receptors, which mediate the primary form of synaptic inhibition in the brain. This suggests that, through production of endozepines, brain cells and circuits can-self regulate, to dynamically enhance synaptic inhibition as needed to suppress seizures as they arise from ongoing brain activity. While the existence of DBI-related antiepileptic endozepines has now been demonstrated, little is known regarding the cellular source of endozepines, nor of the means through which they are secreted from cells or processed in the extracellular space to exert their action. The proposed experiments have three aims. 1) Determine whether astrocytes are the source of endozepines, as they express very high levels of DBI, and appear to have a high capacity for secretion, 2) determine the pathways through which cells, most likely astrocytes, sense activity and then respond through secretion and processing of DBI, and 3) Identify the final endozepine molecule (or molecules), which does not appear to be DBI itself, but a protein fragment of DBI. We will use electrophysiological assays to document functional endozepine activity in all three aims. Assays will include determining the kinetics of spontaneous inhibitory post-synaptic currents, an effective assay for detection of exogenous or endogenous allosteric modulation of synaptic GABAA receptors, and responses to high-speed iontophoretic GABA application, a sensitive assay for endozepine activity, network analysis of large-scale thalamic networks in vitro, and EEG analysis of seizure susceptibility in vivo. These studies will be facilitated by the availability of mutant mice that alow for targeted deletion of DBI from astrocytes, and by fluorescent reporter mice that allow for detection of the range and extent of deletion. Overall the results of the proposed experiments will provide mechanistic information regarding endozepine signaling and whether this natural brain activity might ultimately be targeted for therapeutic intervention in epilepsy and other neuropsychiatric disorders of altered GABA signaling.

描述（由申请人提供）：我们最近表明，天然存在的神经活性化合物，即与大脑中的蛋白质地西泮结合抑制剂（DBI）相关的内氮卓类药物，可以模仿苯二氮卓类药物的活性，而苯二氮卓类药物是治疗癫痫的有效方法。苯二氮卓类药物是 GABAA 受体的变构调节剂，介导大脑中突触抑制的主要形式。这表明，通过产生内氮平，脑细胞和脑回路可以自我调节，根据需要动态增强突触抑制，以抑制持续大脑活动引起的癫痫发作。虽然现已证明与 DBI 相关的抗癫痫内氮平的存在，但人们对内氮平的细胞来源以及它们从细胞中分泌或在细胞外空间中加工以发挥作用的方式知之甚少。拟议的实验有三个目标。 1) 确定星形胶质细胞是否是内氮平的来源，因为它们表达非常高水平的 DBI，并且似乎具有很高的分泌能力，2) 确定细胞（很可能是星形胶质细胞）感知活动然后通过分泌做出反应的途径和 DBI 的加工，以及 3) 鉴定最终的内氮平分子（或多个分子），该分子似乎不是 DBI 本身，而是 DBI 的蛋白质片段。我们将使用电生理学测定来记录所有三个目标的功能性内氮平活性。测定将包括确定自发抑制性突触后电流的动力学、检测突触 GABAA 受体的外源性或内源性变构调节的有效测定、以及对高速离子电渗 GABA 应用的反应、内氮平活性的灵敏测定、网络分析体外大规模丘脑网络，以及体内癫痫易感性的脑电图分析。这些研究将通过允许从星形胶质细胞中定向删除 DBI 的突变小鼠的可用性以及允许检测删除范围和程度的荧光报告小鼠来促进。总体而言，拟议实验的结果将提供有关内氮平信号传导的机制信息，以及这种自然大脑活动是否最终可能成为治疗干预癫痫和 GABA 信号传导改变的其他神经精神疾病的目标。