Thalamocortical network dysfunction in a novel genetic model of GRIN2D developmental and epileptic encephalopathy

GRIN2D 发育性和癫痫性脑病新型遗传模型中的丘脑皮质网络功能障碍

• 批准号: 10195508
• 负责人: WAYNE N. FRANKEL
• 金额: $ 44.55万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-04-01 至 2023-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10195508
• 关键词: Absence Epilepsy; Acute; Adult; Affect; Animal Genetics; Animal Model; Animals; Attention; Awareness; Biological Assay; Brain; Brain region; Cell Nucleus; Cell physiology; Cells; Cerebral cortex; Childhood; Clinical; Cognition; Cognitive; Collaborations; Collection; Data; Development; Developmental Delay Disorders; Docking; Electrophysiology (science); Epilepsy; Epileptogenesis; Equilibrium; Etiology; Evaluation; Future; Generations; Genes; Genetic; Genetic Models; Glutamates; Glycine; Goals; Hippocampus (Brain); Impaired cognition; Impairment; In Vitro; Investigation; Kinetics; Laboratories; Maintenance; Measures; Mediating; Mediator of activation protein; Membrane Proteins; Methods; Modeling; Motor; Motor Seizures; Mus; Mutation; Mutation Analysis; N-Methyl-D-Aspartate Receptors; N-Methylaspartate; Neurologic Symptoms; Neurons; Pathogenicity; Pathologic; Pathology; Patients; Pharmacology; Phenotype; Physiologic pulse; Physiology; Population; Predisposition; Preparation; Property; Proteins; Receptor Activation; Regulation; Reproducibility; Research; Rodent Model; Seizures; Shapes; Signal Transduction; Site; Sleep; Slice; Source; Structure; Synapses; System; Thalamic structure; Therapeutic; Time; Whole-Cell Recordings; Work; base; behavioral impairment; biophysical analysis; cell cortex; cognitive enhancement; density; design; epileptic encephalopathies; excitotoxicity; experience; experimental study; functional disability; gain of function mutation; gene therapy; improved; in vivo; inhibitory neuron; innovation; insight; mouse model; network dysfunction; neural circuit; neuropsychiatric symptom; neurotransmission; novel; patch clamp; postnatal development; preservation; programs; protein complex; response; sleep regulation; somatosensory; success; synaptic function; synaptic inhibition; synaptogenesis; targeted treatment; voltage clamp

PROJECT SUMMARY Developmental and epileptic encephalopathy (DEE) is a collection of severe childhood seizure disorders, with a significant and diverse genetic component. DEE patients usually experience a significant seizure burden and suffer from cognitive and developmental impairments, as well as sleep and motor disturbances. The 50 or more genes harboring DEE-causing mutations include the “GRIN” genes, which encode components of membrane protein complexes that are important for electrochemical signaling between neurons. Mutations in the GRIN2D subunit cause particularly severe and intractable DEE. We recently developed a mouse model of GRIN2D carrying a mutation that has recurred several times in GRIN2D DEE patients. These mice have very robust epileptic features, including both convulsive seizures and non-convulsive seizures known to be regulated by signaling between the cerebral cortex and the thalamus (i.e. thalamocortical network). This thalamocortical network is also associated with regulation of sleep, awareness, and the activity of many other brain regions. In preliminary findings, we also noticed that the protein product of Grin2D is expressed in excitatory and inhibitory cells of the cortex, while it is enriched in the inhibitory cells of the thalamus. Additionally, the primary sites of neuronal signaling – the synapse – have unusual structural features in the cortex, suggesting that they do not develop normally. Altogether, these preliminary data motivate an examination of how mutation in Grin2D alters the function of the cortex and thalamus. In this pilot program, we will apply electrophysiological approaches to measure the function of synapses in the GRIN2D DEE model to determine if structural changes correspond to functional impairments. We will also identify the neuronal connections that are most severely affected within the thalamocortical network in GRIN2D DEE. Aim1 will use slice electrophysiology methods to examine population-level responses within the cortex and thalamus to look for susceptibility of these regions to generate seizure-like activity. We will also adapt innovative approaches to dissect the component parts of the response in the cortex, which will allow us to efficiently pinpoint amongst the many connections in the cortex, which are most likely altered by the Grin2D mutation. These network-level effects will be further explored in Aim2 using intracellular whole-cell patch clamp recordings of synaptic currents. Aim2 will assess two distinct modes of GRIN2D signaling, synaptic and tonic, which are associated with different cellular consequences and are likely involved in the GRIN2D DEE pathogenic mechanism. Together these experiments will determine the consequence of the GRIN2D DEE mutation on the activity of neural circuits, which are implicated in the generation of seizures in these animals, and will determine, at the cellular level, the underlying mechanism of epileptogenesis. This study is an important first step for determining how GRIN2D shapes the development and maintenance of thalamocortical circuits (under normal conditions and in a DEE model), information which will guide future efforts to develop targeted corrective therapeutics.

项目摘要 发育和癫痫性脑病（DEE）是严重的童年癫痫发作的集合， 一个重要而多样的遗传成分。 DEE患者通常会出现明显的癫痫发作和 患有认知和发育障碍，睡眠和运动灾害。 50或 携带DEE突变的更多基因包括“笑”基因，该基因编码的组成部分 膜蛋白复合物对于神经元之间的电化学信号很重要。突变 Grin2D亚基会引起特别严重且顽固性的迪伊（Dee）。我们最近开发了一个鼠标模型 Grin2d携带一种突变，该突变在Grin2d Dee患者中复发了多次。这些老鼠非常 强大的癫痫特征，包括抽搐性癫痫发作和已知的非驱动性癫痫发作 由大脑皮层和丘脑（即丘脑皮层网络）之间的信号传导调节。这 丘脑皮质网络还与睡眠，意识和其他许多其他活动有关 大脑区域。在初步发现中，我们还注意到Grin2d的蛋白质产物在 皮质的兴奋性和抑制性细胞，而丘脑富集丘脑的抑制细胞。 此外，神经元信号的主要部位 - 突触 - 具有异常的结构特征 皮质，表明它们不正常。这些初步数据动机总共 检查Grin2D突变如何改变皮质和丘脑的功能。在这个试点计划中，我们 将采用电生理方法来测量GRIN2D DEE模型中突触的功能 确定结构变化是否对应于功能障碍。我们还将确定神经元 在Grin2d Dee的丘脑皮质网络中受到最严重影响的连接。 AIM1将使用 切片电生理方法检查皮质和丘脑内种群水平的反应以查看 为了使这些区域的敏感性产生癫痫发作活性。我们还将适应创新方法 剖析皮质中响应的组件部分，这将使我们能够有效地查明 皮质中的许多连接很可能会因grin2d突变而改变。这些网络级别 使用细胞内全细胞贴片夹突触记录，将在AIM2中进一步探索效果 AIM2将评估两种不同的Grin2D信号传导，突触和补品的模式，它们相关 具有不同的细胞后果，可能参与GRIN2D DEE致病机制。 这些实验将共同确定Grin2d Dee突变对活动的结果 神经回路是在这些动物中产生的癫痫发作中实施的，并将确定在 细胞水平，癫痫发生的潜在机制。这项研究是确定的重要第一步 GRIN2D如何塑造丘脑皮质回路的发展和维护（在正常条件下） 在DEE模型中），将指导未来努力开发有针对性的纠正疗法的信息。