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Elucidating pathogenic mechanisms in STRADA-related brain malformation and epilepsy

阐明 STRADA 相关脑畸形和癫痫的致病机制

基本信息

批准号：
10681308
负责人：
Louis Tuong Chinh Dang
金额：
$ 43.31万
依托单位：
UNIVERSITY OF MICHIGAN AT ANN ARBOR
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-08-15 至 2027-06-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10681308
关键词：
3-Dimensional Affect Antiepileptogenic Biological Assay Brain Calcium Cell Culture Techniques Cell Therapy Cells Cerebrum Child Complex Cortical Dysplasia Cortical Malformation Data Development Disease Dorsal Effectiveness Electrophysiology (science)Epilepsy Epileptogenesis Etiology FRAP1 gene Feedback Genes Genetic Genetic study Goals Human Hyperactivity Image Immunohistochemistry Impaired cognition Impairment Individual Intellectual functioning disability Interneurons Knowledge Measures Megalencephaly Modeling Morbidity - disease rate Morphology Mutation Neuroglia Neuronal Differentiation Neurons Organoids Outcome Pathogenesis Pathogenicity Pathway interactions Patients Pharmaceutical Preparations Phenotype Polyhydramnios, megalencephaly, and symptomatic epilepsy Process Proliferating Prosencephalon Radial Seizures Signal Pathway Signal Transduction Sirolimus Structure Syndrome Testing Therapeutic Tissue-Specific Gene Expression Transcription Alteration Transplantation Tuberous Sclerosis Up-Regulation Work analog autism spectrum disorder brain abnormalities brain malformation cell fate specification cell type disability excitatory neuron glial cell development in vitro Model induced pluripotent stem cell inhibitory neuron innovation insight loss of function loss of function mutation mTORopathies malformation migration mortality multi-electrode arrays mutant neural neurodevelopment neurogenesis novel novel therapeutics pharmacologic prevent resistance mechanism response single-cell RNA sequencing stem cell model stem cells targeted treatment therapeutic target therapy development treatment strategy

项目摘要

PROJECT SUMMARY Epilepsy is a major cause of morbidity, mortality, disability, and expense, and affects over 470,000 children in the U.S. While many medications to control seizures have been developed, about 30% of patients do not respond to medications, and to date, there are no medications that can prevent or halt the progression of epilepsy. Recently, many genetic causes of epilepsy have been identified, providing insights into pathways involved in epileptogenesis. Mutations causing hyperactivity of the mTOR pathway (so-called “mTORpathies”) have emerged as an important cause of cerebral malformations and epilepsy, including tuberous sclerosis complex, focal cortical dysplasia, and polyhydramnios, megalencephaly, and symptomatic epilepsy (PMSE) syndrome, which is associated with severe epilepsy and intellectual disability and is caused by a loss-of- function in the STRADA gene. Inhibition of the mTOR pathway with rapamycin or its analogs can help in mTORopathies, but many individuals still have seizures that do not respond. Prior studies generated stem cells from individuals with PMSE and differentiated them into excitatory neurons in 2-D culture and dorsally-fated human cerebral organoids, 3-D neural structures that resemble the developing cortex and predominantly contain excitatory neurons. The PMSE organoids demonstrated mTOR hyperactivity, increased size, abnormal morphology, delayed neuronal differentiation, and an increase in outer radial glia, a progenitor cell that is responsible for the expanded size of the human brain. These findings explain megalencephaly in PMSE, but the intermediate mechanisms by which STRADA loss-of-function results in these observed phenotypes is not known. Furthermore, the effect of STRADA loss-of-function on inhibitory interneurons that originate from ventral forebrain structures is not known. Abnormal inhibitory interneurons are a major cause of epilepsy and autism, both prominent features of mTORopathies. This proposal will test the central hypothesis that loss of STRADA causes cortical malformation by mTOR complex 1 hyperactivity, and that inhibitory interneuron development is also impaired, resulting in epilepsy. This innovative proposal will use dorsally-fated organoids to identify which signaling pathway alterations downstream of STRADA result in altered cortical development, and will determine whether compensatory feedback signals hinder the effectiveness of rapamycin treatment (Aim 1). We will also generate fusions between ventrally-fated and dorsally-fated organoids to study interneuron development, interneuron migration, cell-type specific transcriptional alterations (Aim 2), as well as neuronal network hyperexcitability that can result in epilepsy (Aim 3). The proposed study will have significant impact because understanding the signaling pathways and cell types responsible for pathogenesis in PMSE will provide a platform to develop mechanistically driven therapies that can halt or reverse epileptogenesis for mTORopathies, and our findings should be applicable to epilepsies in a broader context.

项目概要癫痫是发病率、死亡率、残疾和费用的主要原因，影响着超过 470,000 名儿童美国虽然已经开发出许多控制癫痫发作的药物，但约 30% 的患者并没有对药物有反应，迄今为止，还没有药物可以预防或阻止病情的进展癫痫。最近，许多癫痫的遗传原因已被确定，提供了对途径的见解参与癫痫发生。导致 mTOR 通路过度活跃的突变（所谓的“mTORpathies”）已成为脑畸形和癫痫（包括结节性硬化症）的重要原因复杂、局灶性皮质发育不良、羊水过多、巨脑畸形和症状性癫痫 (PMSE) 综合症，与严重癫痫和智力障碍有关，是由丧失- STRADA 基因中的功能。用雷帕霉素或其类似物抑制 mTOR 通路有助于 mTORopathies，但许多人仍然出现无反应的癫痫发作。先前的研究产生了干细胞来自患有 PMSE 的个体，并将其分化为二维培养中的兴奋性神经元和背侧命运神经元人类大脑类器官，类似于发育中的皮层的 3D 神经结构，主要是含有兴奋性神经元。 PMSE 类器官表现出 mTOR 过度活跃、大小增大、异常形态、神经元分化延迟以及外放射状胶质细胞（一种祖细胞）的增加负责人脑尺寸的扩大。这些发现解释了 PMSE 中的巨脑畸形，但是 STRADA 功能丧失导致这些观察到的表型的中间机制并不明确已知。此外，STRADA 功能丧失对源自抑制性中间神经元的影响腹侧前脑结构尚不清楚。异常的抑制性中间神经元是癫痫的主要原因自闭症，这都是 mTORopathies 的突出特征。该提案将检验中心假设，即损失 STRADA 通过 mTOR 复合物 1 过度活跃导致皮质畸形，并且抑制性中间神经元发育也会受到损害，导致癫痫。这项创新提案将使用背侧类器官确定 STRADA 下游哪些信号通路的改变会导致皮质发育改变，并将确定补偿反馈信号是否阻碍雷帕霉素治疗的有效性（目标 1）。我们还将生成腹侧类器官和背侧类器官之间的融合来研究中间神经元发育、中间神经元迁移、细胞类型特异性转录改变（目标 2）以及神经元网络过度兴奋可导致癫痫（目标 3）。拟议的研究将具有重大意义影响，因为了解负责 PMSE 发病机制的信号通路和细胞类型将提供一个平台来开发机械驱动的疗法，可以阻止或逆转癫痫发生 mTORopathies，我们的研究结果应该适用于更广泛的癫痫病。