Genetic Modifiers of Childhood Epilepsy

儿童癫痫的基因修饰

基本信息

批准号：
10539313
负责人：
Jennifer A Kearney
金额：
$ 49.31万
依托单位：
NORTHWESTERN UNIVERSITY AT CHICAGO
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-09-01 至 2024-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10539313
关键词：
129 Mouse Address Affect Age Age Months Alleles American Animals Behavioral Brain Buffers Candidate Disease Gene Cells Chromosome 7 Chromosome 8 Chromosomes Clinical Code Cognitive Compensation Complex Congenic Strain DNA Data Data Set Development Developmental Delay Disorders Disease Epilepsy Etiology Evaluation Exhibits Failure Febrile Convulsions Functional disorder Gene Expression Gene Modified Genes Genetic Genetic Predisposition to Disease Genetic Transcription Goals Heterozygote Hippocampus Human Individual Infant Inherited Intellectual functioning disability Interneurons Ion Channel Longevity Loss of Heterozygosity Maps Medicine Mus Mutation Neurologic Neurons Pathogenicity Pathway interactions Patients Persons Phase Phenotype Population Predisposition Proteins QTL Genes Quantitative Trait Loci Refractory Reporting Resistance Resolution Risk SCN1A protein Seizures Severities Severity of illness Sodium Sodium Channel Surveys Synapses Syndrome Transcriptional Regulation Variant cell type childhood epilepsy density differential expression dravet syndrome epileptic encephalopathies genetic pedigree improved in vivo insight loss of function loss of function mutation mortality risk nervous system disorder neurotransmission novel therapeutic intervention permissiveness premature preservation promoter response risk variant single nucleus RNA-sequencing single-cell RNA sequencing sudden unexpected death in epilepsy therapeutic target trait transcriptome sequencing voltage

项目摘要

Epilepsy is a common neurological that will affect 1 in 26 Americans during their lifetime. Mutations in SCN1A, encoding the neuronal voltage-gated sodium channel Nav1.1, are the most common genetic cause of epilepsy. Over 1600 SCN1A mutations have been reported in individuals with epilepsy of varying severity, ranging from mild febrile seizures to Dravet syndrome, a severe infant-onset epileptic encephalopathy caused by heterozygous loss-of-function mutations. Dravet syndrome is characterized by a variety of seizure types, developmental delay and elevated mortality risk. A common feature of monogenic epilepsies is variable expressivity in individuals carrying the same mutation, suggesting that clinical severity is influenced by genetic modifiers. Mice with heterozygous deletion of Scn1a (Scn1a+/-) recapitulate core features of Dravet syndrome phenotypes, including spontaneous seizures and increased mortality risk. Loss of Scn1a results in reduced sodium current in hippocampal GABAergic interneurons, resulting in failure of inhibition and excitatory/inhibitory imbalance in the brain. Phenotype severity in Scn1a+/- mice is strongly dependent on strain background. Scn1a+/- mice on the resistant 129 strain (129.Scn1a+/-) have no overt phenotype and live a normal lifespan. In contrast, Scn1a+/- mice on a [129xB6]F1 strain (F1.Scn1a+/-) exhibit spontaneous seizures and premature lethality, with 50% dying by 1 month of age. Strain-dependent differences are also evident at the level of neuron subtypes. GABAergic interneurons isolated from the susceptible F1.Scn1a+/- mice exhibit decreased sodium current density compared to wildtype littermates, while sodium current density is preserved in interneurons isolated from 129.Scn1a+/- relative to wildtype littermates. This suggests that interneurons from strain 129 compensate for the loss of Nav1.1, while F1 interneurons do not. Based on the strain-dependent difference in phenotypes at the whole animal and cellular levels, we hypothesize that genetic modifiers influence Scn1a+/- phenotype severity due to differences in compensatory capacity among neuronal subtypes in the context of Scn1a heterozygous deletion. We previously mapped several Dravet survival modifier (Dsm) loci that influence premature lethality of Scn1a+/- mice. In the current proposal, we will address our hypothesis in three aims. First, we will perform fine mapping and candidate gene analysis at two Dsm loci on mouse chromosomes 7 and 8. Second, we will perform single cell RNA-seq analysis to characterize differences in cell composition and gene expression in specific cell subpopulations during the critical phase of phenotype onset in epilepsy susceptible F1.Scn1a+/- and resistant 129.Scn1a+/- mice. Third, we will evaluate the modifier potential of candidate genes in vivo using transcriptional modulation to up- and down-regulate candidate gene expression. Results from these studies will identify modifier genes and pathways that influence phenotype severity in Scn1a+/- mice. Identification of modifier genes that influence severity of Dravet syndrome will provide insight into the pathophysiology of epilepsy and will suggest novel therapeutic approaches for improved treatment of human patients.

癫痫是一种常见的神经系统，一生中将影响26名美国人中的1个。 SCN1a中的突变，编码神经元电压门控通道NAV1.1是癫痫的最常见遗传原因。在患有不同严重程度的癫痫患者中，已有超过1600个SCN1a突变轻度发热性癫痫发作对Dravet综合征，这是一种严重的婴儿发作性癫痫性脑病杂合功能丧失突变。 Dravet综合征的特征是多种癫痫发作类型，发育延迟和死亡率升高。单基因癫痫的共同特征是可变的携带相同突变的个体的表现力，表明临床严重程度受遗传的影响修饰符。 SCN1A（SCN1A +/-）杂合缺失的小鼠概括了Dravet综合征的核心特征表型，包括自发癫痫发作和增加死亡率风险。 SCN1A的丢失导致减少海马GABA能中间神经元中的钠电流，导致抑制和兴奋性/抑制作用失败大脑失衡。 SCN1A +/-小鼠中的表型严重程度在很大程度上取决于应变背景。 scn1a +/- 抗性129菌株（129.scn1a +/-）上的小鼠没有明显的表型，并且过着正常的寿命。相比之下， [129xB6] F1菌株（F1.scn1a +/-）上的SCN1A +/-小鼠表现出自发的癫痫发作和早产性，并具有 50％死于1个月大。在神经元亚型的水平上，菌株依赖性差异也很明显。从易感F1.SCN1A +/-小鼠中分离出的GABA能中神经元显示出钠电流密度降低与野生型同窝窝相比，钠电流密度保留在从中分离出来 129.SCN1A +/-相对于Wildtype窝窝。这表明来自菌株129的中间神经元补偿了 NAV1.1的损失，而F1中间神经元则不会。基于在表型的应变依赖性差异整个动物和细胞水平，我们假设遗传修饰剂会影响SCN1A +/-表型严重程度由于SCN1A杂合的背景下神经元亚型之间的补偿能力差异删除。我们以前绘制了几个Dravet生存修饰符（DSM）基因座，影响了过早的致死率 SCN1A +/-小鼠。在当前的提案中，我们将以三个目标解决我们的假设。首先，我们会表现良好小鼠染色体上的两个DSM基因座的映射和候选基因分析7和8。第二，我们将执行单细胞RNA-seq分析以表征特定细胞中细胞组成和基因表达的差异癫痫发作的临界临界阶段临界阶段的亚群 129.scn1a +/-小鼠。第三，我们将使用转录在体内评估候选基因的修饰物潜力调节以上调和下调候选基因表达。这些研究的结果将确定修饰符影响SCN1A +/-小鼠表型严重程度的基因和途径。鉴定修饰符基因影响Dravet综合征的严重程度将提供对癫痫病理生理学的见解，并建议新的治疗方法可改善对人类患者的治疗。