Changes in the Ionic Basis of GABAergic Inhibition that Contribute to Post-traumatic Epilepsy

导致创伤后癫痫的 GABA 能抑制离子基础的变化

• 批准号: 10713240
• 负责人: Kevin J. Staley
• 金额: $ 137.95万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2028-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10713240
• 关键词: Acute; Animals; Anticonvulsants; Antiepileptogenic; Area; Automobile Driving; Behavior; Brain; Brain Injuries; Chloride Ion; Chlorides; Chondroitinases; Chronic; Cicatrix; Compensation; Data; Disinhibition; Electroencephalography; Elements; Epilepsy; Epileptogenesis; Etiology; Extracellular Matrix; Extracellular Space; Family suidae; Functional disorder; Funding; Gliosis; Goals; Human; Image; Injury; Intractable Epilepsy; Investigation; Kinetics; Matrix Metalloproteinase Inhibitor; Measures; Mediating; Medical; Membrane; Microscope; Microscopy; Miniature Swine; Modeling; Neocortex; Neurons; Phase; Photons; Post-Traumatic Epilepsy; Proteoglycan; Research; Research Personnel; Research Support; Resected; Resolution; Seizures; Signal Transduction; Structure; Sulfate; System; Testing; Time; Translational trial; Trauma; animal facility; brain remodeling; brain tissue; cost; driving force; experimental study; extracellular; fluorescence lifetime imaging; gamma-Aminobutyric Acid; high throughput screening; imaging facilities; in vitro Model; in vivo; in vivo calcium imaging; injured; multiphoton imaging; neocortical; novel; pharmacologic; preservation; prevent; programs; prophylactic; receptor; reconstruction; screening program; tool; two-photon

Brain injury is a common cause of medically intractable epilepsy. Because we do not understand the underlying pathophysiology, we can’t reduce the burden of medical intractability. The overarching goal of this research program is to exploit a recently developed large animal gyrencephalic model of neocortical post-traumatic epilepsy (PTE) to elucidate a mechanism of neocortical epileptogenesis: chronic compromise of the ionic basis for GABA-mediated inhibition. Disinhibition is a fundamental element of ictogenesis, but thus far we have not found the mechanism of disinhibition in chronic epilepsy. There are two salient clues: first, anticonvulsants that increase GABA conductance often do not ameliorate PTE; and second, studies in human intractable epilepsy have found a positive, disinhibitory shift in the reversal potential for GABAA receptor-mediated membrane currents (EGABA). Here we will test the hypothesis that glial reconstruction of the brain’s extracellular matrix after injury results in increased displacement of extracellular chloride (Cl-o) by the sulfate moieties of the proteoglycans that comprise the new matrix. To test this hypothesis, we will employ a large-animal PTE model in which local epileptogenesis occurs after well-characterized neocortical injury (Project 1 and Large Animal Core). This localization of epileptogenesis is critical for correlation of changes in Cl-o, network structure, and epilepsy. In this injured neocortical area, we will use longitudinal 2-photon in vivo calcium imaging to test for the network changes expected from disinhibition (Project 2 and Microscopy Core). In the injured neocortical area, we will use 2-photon Fluorescence Lifetime Imaging (FLIM) and newly-synthesized Cl- indicators to test for changes in the local Cl-o and intracellular chloride (Cl-i ) that would drive disinhibition by depolarizing EGABA and reducing the efficacy of shunting inhibition (Project 3). The 3 projects have a common third aim: to correlate epileptogenesis (Project 1) with network disinhibition (Project 2) that are associated with chronic changes in Cl-o and Cl-i (Project 3). Together, these Projects and Cores will test a novel mechanism of epileptogenesis and medical intractability that could be ameliorated by short-term inhibition of the disassembly of the brain’s extracellular matrix at the time of injury using MMP inhibitors whose efficacy will be screened in Project 3, Aim 2.

脑损伤是医学上棘手发作的常见原因。因为我们不了解 潜在的病理生理学，我们无法减少医学上的顽固性的燃烧。总体 该研究计划的目标是探索最近开发的大型动物沟渠模型 新皮层创伤后癫痫（PTE）阐明了新皮质癫痫发生的机制： GABA介导的抑制的离子基础的慢性妥协。抑制是基本的 诊断的元素，但到目前为止，我们尚未发现慢性抑制的机制 癫痫。有两个突出的簇：首先，增加GABA电导的抗惊厥药通常会这样做 不改善PTE；其次，对人顽固性癫痫的研究发现了阳性 GABAA受体介导的膜电流（Egaba）的逆转潜力的抑制作用转移。 在这里，我们将测试以下假设：受伤后脑部细胞外基质的神经胶质重建 导致细胞外氯化物（CL-O）的位移增加 构成新矩阵的蛋白聚糖。为了检验这一假设，我们将采用大动物 局部癫痫发生后发生在良好的新皮层损伤之后发生的PTE模型（项目1 和大动物核心）。癫痫发生的这种定位对于CL-O变化的相关性至关重要 网络结构和癫痫。在这个受伤的新皮层区域，我们将在 体内钙成像以测试因抑制预期的网络变化（项目2和 显微镜核心）。在受伤的新皮层区域，我们将使用2光子荧光寿命成像 （FLIM）和新合成的Cl-nideator测试局部CL-O和细胞内氯化物的变化 （CL-I）通过将埃加巴分裂并降低抑制效率来驱动抑制作用 （项目3）。这3个项目具有第三个共同的目的：将癫痫发生（项目1）与 与CL-O和CL-I的慢性变化相关的网络抑制（项目2）（项目3）。 这些项目和核心将共同测试癫痫发生和医学的新机制 可以通过短期抑制大脑的拆卸来改善难治性 使用MMP抑制剂受伤时细胞外基质的效率将在项目中筛选 3，目标2。