Development of aberrant cortical interneuron circuitry in genetic mouse models of absence epilepsy

失神性癫痫遗传小鼠模型中异常皮质中间神经元回路的发展

• 批准号: 10586134
• 负责人: Xiaolong Jiang
• 金额: $ 44.94万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-06-15 至 2025-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10586134
• 关键词: Absence Epilepsy; Affect; Animal Model; Behavior; Behavioral; Biological Assay; Brain; Cells; Cerebral cortex; Child; Clear Cell; Data; Defect; Development; Disease; Disparate; Electrophysiology (science); Epilepsy; Generations; Genes; Genetic; Genetic Predisposition to Disease; Genotype; Impaired cognition; Impairment; Inherited; Interneurons; Intervention; Lesion; Measures; Mediating; Methods; Modeling; Molecular; Morbidity - disease rate; Morphology; Mus; Mutant Strains Mice; Mutation; Neurons; Parvalbumins; Pathogenicity; Pathologic; Patients; Pattern; Persons; Phenotype; Property; Recurrence; Role; Seizures; Societies; Somatosensory Cortex; Somatostatin; Stereotyping; Structure; System; Testing; Time; United States; cell type; cognitive function; comorbidity; cost; gene discovery; in silico; in vivo; innovation; insight; mouse model; mutant; network models; neural; neural circuit; neural network; neurodevelopment; novel; therapeutic target

Abstract Epilepsy affects over 2 million of people in the United States, causing significant morbidity with a high cost to society. While the behavioral and electrophysiological correlates of seizures in patients and animal models have been studied for over a century, the underlying circuit abnormalities are still being elucidated. Generalized spike-wave (SW) absence sei- zures are the most common seizure disorder in children and thought to be exclusively of genetic origin. While over 20 genes are discovered and studied in SW epilepsies, it is still unclear how each genetic lesion impairs normal circuit devel- opment and ultimately results in a seizure-prone cortical circuit. Since the SW seizure phenotype can be very similar de- spite disparate genetic etiologies, a stereotypical circuit deficit may exist which underlies the expression of this seizure pattern. More recently, as we have begun to understand the wiring principles of cortical microcircuits at the level of cell types, it has become possible to ask how disruption of these canonical networks may be responsible for initiating seizure activity and impairing cognitive functions in SW epilepsies, whether the pathogenic circuit changes overlap despite dis- parate molecular lesions, and how a seizure-prone circuit emerges from inherited molecular defects to favor seizure on- set at predictable developmental time-points. This information not only suggests novel and broadly-applicable therapeu- tic targets, but also leads to valuable insights into the functional roles of distinct cell types and specific connectivity principles in normal brain. To answer these important questions, we are taking advantage of three mouse models of ab- sence epilepsy, stargazer, tottering and Gabrg2 mutant mice, which harbor mutations in three unrelated genes but share the same SW phenotype, and propose a comprehensive microcircuit comparison among distinct genotypes at the level of cell types and their connections. We perform a large-scale circuit analysis across a whole column of the somatosen- sory cortex (S1) in three models along the seizure development, by leveraging a high-throughput multi-patching method (up to 12-patch) we recently developed. We will measure multiple neuronal features of distinct cell types within the S1 epileptic circuit, with an emphasis on connectivity and morphology of major groups of cortical GABAergic interneurons. In parallel, the same analysis will be performed on WT littermates as controls to reveal cell type-specific connectivity changes as a function of the genotype and developmental stage. These comprehensive, dynamic comparisons, based on large-scale circuit analyses with sensitive, state-of-the-art methods, will reveal the full extent of abnormal microcircuit structure and functions that are closely associated with seizure onset. Our preliminary data uncover several connectivity defects in these models. The most striking is that stereotypical connectivity and morphology of somatostatin-expressing Martinotti cells are severely disrupted, and this disruption appears to emerge only after seizure onset and is shared by models, suggesting a common circuit deficit underlying absence epilepsy. The potential causative circuit mechanisms will be further tested via network modeling and an in vivo chemogenetic assay. Identification of causative circuit deficits gen- eralized across genetically heterogeneous, yet highly stereotyped SW seizures will direct the field toward the develop- ment of innovative, broadly applicable circuit-based interventions for absence epilepsy and its related comorbidities.

摘要 美国有200多万人患有癫痫，发病率很高，给社会带来了高昂的代价。 虽然已经对患者和动物模型中癫痫发作的行为和电生理相关性进行了研究 一个多世纪以来，潜在的电路异常仍在被阐明。广义尖峰波(Sw)的缺失 朱疹是儿童中最常见的癫痫发作障碍，被认为完全是由基因引起的。而超过20岁的人 在短波癫痫中发现和研究了基因，目前尚不清楚每种遗传损伤是如何损害正常电路发育的。 并最终导致易于癫痫发作的大脑皮层回路。由于短波惊厥的表型可能非常相似， 尽管有不同的遗传病因，但可能存在典型的回路缺陷，这是癫痫发作的表现基础。 图案。最近，随着我们开始在细胞水平上了解皮质微电路的连接原理 类型，人们可能会问这些规范网络的破坏可能是如何导致癫痫发作的 短波癫痫患者的活动和认知功能受损，致病回路变化是否重叠 分离的分子损伤，以及如何从遗传的分子缺陷中出现易于癫痫发作的回路，从而有利于癫痫发作- 设定在可预测的发展时间点。这一信息不仅表明了新的和广泛适用的疗法-- TIC靶点，但也导致了对不同细胞类型和特定连接性的功能作用的有价值的见解 正常大脑中的原则。为了回答这些重要的问题，我们利用了三种小鼠模型的ab- 感觉性癫痫、观星者、摇摇欲坠和Gabrg2突变小鼠，这些小鼠有三个无关基因的突变，但有共同的 相同的Sw表型，并在水平上提出了不同基因型之间的综合微电路比较 细胞类型和它们之间的联系。我们对整个躯体组织进行大规模的电路分析- Sory皮质(S1)在三个癫痫模型中的发展，通过利用高通量的多修补方法 (最多12个补丁)我们最近开发的。我们将测量S1内不同细胞类型的多种神经元特征 癫痫回路，重点是大脑皮质GABA能中间神经元的主要群体的连通性和形态。 同时，将对WT仔猪进行同样的分析，作为对照，以揭示特定细胞类型的连接性 随着基因和发育阶段的变化而变化。这些全面、动态的比较基于 用灵敏、最先进的方法进行大规模电路分析，将全面揭示微电路的异常程度 与癫痫发作密切相关的结构和功能。我们的初步数据揭示了几个联系 这些模型中的缺陷。最引人注目的是，生长抑素表达的刻板连接和形态 马蒂诺蒂细胞受到严重破坏，这种破坏似乎只有在癫痫发作后才会出现，并与 模型，表明失神癫痫背后有共同的回路缺陷。潜在的致病电路机制将 通过网络建模和体内化学生成试验进行进一步测试。致病电路缺陷基因的鉴定 跨遗传异质性，但高度刻板印象的短波癫痫发作将引导该领域向发展- 对失神癫痫及其相关并发症进行创新的、广泛适用的电路干预。