Interneuron axonopathy underlies circuit dysfunction in a mouse model of Dravet syndrome

中间神经元轴突病变是 Dravet 综合征小鼠模型中回路功能障碍的基础

基本信息

批准号：
10372046
负责人：
ETHAN M GOLDBERG
金额：
$ 43.75万
依托单位：
CHILDREN'S HOSP OF PHILADELPHIA
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-04-15 至 2024-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10372046
关键词：
Action Potentials Acute Affect Anatomy Animal Model Axon Biological Models Brain Brain imaging Calcium Cell Transplantation Cells Cerebral cortex Cerebrum Child Clinical Closure by clamp Data Development Developmental Delay Disorders Diagnosis Disease Distal Electroencephalography Electrophysiology (science)Epilepsy Experimental Animal Model Experimental Models Failure Frequencies Functional disorder Future Generations Gene Mutation Generations Genes Goals Human Image Immunohistochemistry Impairment In Vitro Intellectual functioning disability Intellectual impairment Interneurons Ion Channel Knowledge Lateral Maps Measures Medical Genetics Membrane Molecular Mus Mutation Neurodevelopmental Disorder Neurons Neurosciences Outcome Parvalbumins Pathogenesis Pathology Patient Care Patient-Focused Outcomes Patients Pattern Physiological Physiology Property Pyramidal Cells Quality of life Recovery Regulation Research Research Personnel Resistance Role Seizures Sensory Severities Site Slice Sodium Somatosensory Cortex Somatostatin Sudden Death Synapses Testing Time Up-Regulation Validation Vibrissae Whole-Cell Recordings Wild Type Mouse Work autism spectrum disorder awake axonopathy biophysical properties cell type density dravet syndrome experience experimental study gene therapy genetic disorder diagnosis in vivo in vivo imaging infancy innovation mouse model neuronal cell body novel pre-clinical precision medicine response spatiotemporal synaptic failure targeted treatment transmission process two-photon voltage voltage clamp

项目摘要

PROJECT SUMMARY Dravet syndrome is a severe neurodevelopmental disorder that affects 1 in 16,000 children and is defined by treatment-resistant epilepsy, developmental delay, intellectual disability, autism spectrum disorder, and a high rate of sudden death. Dravet syndrome is caused by mutation in the gene SCN1A, which encodes the sodium (Na+) channel Nav1.1 How SCN1A mutation leads to the clinical entity known as Dravet syndrome remains unclear; this gap in knowledge has profoundly limited the practical impact that such a diagnosis has on treatment, quality of life, and long-term outcome for patients with this disorder. Prior work in experimental animal models of Dravet syndrome including Scn1a+/- mice suggests that loss of Nav1.1 leads to epilepsy via dysfunction of GABAergic inhibitory interneurons in the cerebral cortex, with the most prominent identified abnormalities being impaired action potential generation in a critical subtype of interneuron known as the parvalbumin-positive fast-spiking interneuron (PV-IN). However, data presented here indicates that, surprisingly, PV-IN dysfunction is transient, being restricted to a brief time window in early development, with subsequent recovery of high frequency firing. Preliminary data suggests that the specific locus of pathology in Dravet syndrome is actually PV-IN axons, with abnormal action potential propagation leading to conduction delay and synaptic failure, even though PV-INs have recovered the ability to generate action potentials at high frequency. This finding has important implications for the development of novel treatment approaches for Dravet syndrome, such as cell transplantation, gene therapy, or precision medicine. This new 5-year application from the lab of an early stage investigator uses innovative neuroscience approaches to test this new hypothesis as to the mechanism of pathology in Dravet syndrome. Proposed experiments will establish the molecular identity and physiological properties of Na+ channels in PV-IN axons in Scn1a+/- mice as compared to wild-type controls using targeted recordings from interneuron axons and detailed immunohistochemistry of axonal Na+ channels (Aim 1); determine the impact of PV-IN axonal dysfunction on the timing of feedforward inhibition in cerebral cortical circuits (Aim 2); and assess the activity of defined subsets of neurons in awake, behaving Scn1a+/- mice using in vivo imaging and electrophysiology to corroborate in vitro findings (Aim 3). The overall outcome of the proposed experiments will set forth a unifying hypothesis as to the pathophysiology of Dravet syndrome. Such knowledge is critical to the development of novel, targeted therapies for this currently incurable and untreatable disease. The long-term objective of this line of research is to apply preclinical data from experimental model systems to the development of new, mechanistically oriented therapies in human patients.

项目摘要 Dravet综合征是一种严重的神经发育障碍，影响16,000名儿童中有1个，并由防治癫痫，发育延迟，智力障碍，自闭症谱系障碍和高度猝死率。 Dravet综合征是由基因SCN1a突变引起的，该基因编码钠（Na+）通道NAV1.1 SCN1A突变如何导致被称为Dravet综合征的临床实体尚不清楚；这种知识的差距严重限制了这种诊断的实际影响关于这种疾病患者的治疗，生活质量和长期预后。包括SCN1A +/-小鼠的Dravet综合征实验动物模型的先前工作表明丧失 NAV1.1通过脑皮质中的GABA能抑制性中间神经元的功能障碍导致癫痫最突出的确定异常是在关键亚型中的行动潜力产生受损中间神经元称为白蛋白阳性阳性快速刺激性中间神经元（PV-IN）。但是，此处介绍的数据表明令人惊讶的是，PV-IN功能障碍是短暂的，仅限于早期的短时间窗口开发，随后恢复高频射击。初步数据表明特定 Dravet综合征中病理学的基因座实际上是PV-IN轴突，具有异常动作电位传播即使PV-INS恢复了产生的能力，导致传导延迟和突触失败高频的动作电位。这一发现对新颖的发展具有重要意义 DRAVET综合征的治疗方法，例如细胞移植，基因治疗或精度医学。早期研究者实验室的这项新的5年应用使用创新的神经科学关于Dravet综合征病理学机制检验这一新假设的方法。建议的实验将建立PV-IN轴突中Na+通道的分子身份和生理特性与使用中间轴突的靶向记录相比，在SCN1A +/-小鼠中，与野生型对照相比轴突Na+通道的详细免疫组织化学（AIM 1）；确定PV-IN轴突的影响脑皮质回路中进料抑制时间的功能障碍（AIM 2）；并评估活动在清醒中定义的神经元的子集，使用体内成像和电生理学表现出SCN1A +/-小鼠证实体外发现（AIM 3）。提出的实验的总体结果将阐明有关病理生理学的统一假设 Dravet综合征。这样的知识对于为此的新颖，有针对性的疗法开发至关重要目前无法治愈且无法治疗的疾病。这一研究的长期目标是应用临床前数据从实验模型系统到开发新的，机械方向的人类患者的疗法。