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Defining disease mechanisms in SLC35A2 epilepsy

定义 SLC35A2 癫痫的疾病机制

基本信息

批准号：
10609847
负责人：
Peter B Crino
金额：
$ 68.9万
依托单位：
UNIV OF NORTH CAROLINA CHAPEL HILL
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-07-01 至 2025-04-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10609847
关键词：
3-Dimensional Adult Age of Onset Alleles Astrocytes Biological Assay Brain CRISPR/Cas technology Cell Fraction Cell Line Cell Nucleus Cell Separation Cells Clustered Regularly Interspaced Short Palindromic Repeats Complement Complementary DNA Conceptions Congenital disorders of glycosylation Cortical Dysplasia Cortical Malformation Coupled Data Defect Dendritic Spines Development Disease Electroencephalography Electrophysiology (science)Electroporation Embryonic Development Epilepsy Event FDA approved Freezing Functional disorder Galactose Genes Genotype Germ-Line Mutation Glutamates Glycoconjugates Glycosphingolipids Golgi Apparatus Guide RNA Human Individual Induced pluripotent stem cell derived neurons Intellectual impairment Intractable Epilepsy Kinetics Knock-out Length Link Lipids Liquid Chromatography Mass Spectrum Analysis Metabolic Diseases Microscopy Modeling Molecular Monitor Morphology Mosaicism Mus Mutation Neocortex Neurites Neurons Oligodendroglia Organoids Parents Partial Epilepsies Pathogenicity Pathologic Pathology Pathway interactions Patients Phenotype Polysaccharides Population Process Production Protein Glycosylation Proteoglycan Refractory Resected Role Sampling Scanning Seizures Series Severities Severity of illness Somatic Mutation Specimen Supplementation Syndrome Therapeutic Time Transferase Translating Uridine Diphosphate Galactose Variant Western Blotting Work X Chromosome brain cell brain dysfunction brain tissue cell type clinical phenotype de novo mutation druggable target early onset effectiveness evaluation epileptic encephalopathies fetal genetic variant girls glycosylation hemimegalencephaly in utero induced pluripotent stem cell insertion/deletion mutation loss of function mRNA Expression migration mosaic mosaic loss mouse model multi-electrode arrays mutant neocortical nerve stem cell neural neural network neurodevelopment neurogenesis neuron development neuronal cell body novel offspring patch clamp precision medicine prevent protein transport radiological imaging single nucleus RNA-sequencing transmission process

项目摘要

ABSTRACT Many epilepsy syndromes associated with severe, early-onset seizures result from de novo variants in genes involved in early brain development. Recent studies have also identified somatic variants in focal epilepsy associated with cortical malformations, including hemimegalencephaly and the more common focal cortical dysplasia (FCD) type 2. These post-zygotically acquired variants arise during neurogenesis and are therefore present in only a fraction of cells. Expanding on these early discoveries implicating somatic variants in epilepsy, we recently identified brain-specific somatic mutations in SLC35A2 in individuals with refractory neocortical epilepsy. Germline variants in SLC35A2 were previously implicated in a rare X-linked developmental and epileptic encephalopathy. Our data suggest that somatic variants in SLC35A2 may also be responsible for approximately 17% of intractable non-lesional focal epilepsy cases. The number of cells harboring a pathogenic SLC35A2 variant allele appears to correlate with disease severity, and several of the cases have FCD type 1a (FCD1a) pathology. Pathogenic variants in SLC35A2, both somatic and germline, prevent the Golgi-localized transporter from moving UDP-Galactose (UDP-Gal) into the Golgi apparatus for use in the formation of essential galactosylated glycans. There is theoretical, experimental, and observational data suggesting that Gal supplementation may be able to restore glycosylation to the cell to provide therapeutic benefit. In this study, we will define the functional consequences of SLC35A2 variants in epilepsy. Given that not all cells carry the variant allele in the individuals with a somatic SLC35A2 variant, in Aim 1 we seek to use resected human brain tissue specimens to identify the specific cell types in the brain harboring the variant alleles. This will allow us to determine which cell types contribute to SLC35A2 epilepsy and whether cell-type-specific burden dictates the pathological observations. In Aim 2 we will evaluate the effects of the variants on cell-type-specific glycosylation in human induced pluripotent stem cell (hiPSC)-derived neural progenitor cells and mature glutamatergic neurons, a cell type that we have preliminary data to support involvement in the epileptogenic processes. Since nearly all patients with an SLC35A2 variant have seizures, and a significant fraction has FCD1a, in Aim 3 we will also characterize the effects of the variants on individual and neural network activity, neural migration, and neurodevelopment in both human (e.g., hiPSC-derived neurons, 3-D organoids) and mouse models (e.g., mouse neural progenitors and in utero electroporation). In Aims 2 and 3, we will assess the effectiveness of Gal to restore glycosylation and reverse effects on neuronal development or activity. Collectively, these studies will translate our exciting initial discovery implicating a novel pathway underlying a significant fraction of individuals suffering from intractable seizures into studies of the role of glycosylation defects underlying localized brain dysfunction in focal epilepsy. Given that the glycosylation pathway represents a potentially druggable target, this work may inform precision medicine approaches to the treatment of refractory epilepsy.

摘要