Mechanisms of Genetic Seizure Susceptibility in Juvenile Myoclonic Epilepsy

青少年肌阵挛性癫痫遗传性癫痫易感性机制

基本信息

批准号：
8099781
负责人：
DAVID A. GREENBERG
金额：
$ 54.52万
依托单位：
COLUMBIA UNIVERSITY HEALTH SCIENCES
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-07-15 至 2012-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8099781
关键词：
3&apos Untranslated Regions 5&apos Untranslated Regions 6p21 Adolescence Adolescent Adult Affect Alleles Alternative Splicing American BRD2 gene Behavior Behavioral Brain Brain region Bromodomain Candidate Disease Gene Characteristics Complex Congenital neurologic anomalies DNA Data Data Linkages Data Reporting Disease Electroencephalography Electrophysiology (science)Embryo Epilepsy Equilibrium Essential Genes European Event Exhibits Exons Family Family health status Female Frequencies Functional RNA Gene Expression Generalized Epilepsy Genes Genetic Genetic Polymorphism Genetic Transcription Haplotypes Health Healthcare Systems Heterozygote Human Image Individual Interneurons Introns Juvenile Myoclonic Epilepsy Knock-out Knockout Mice Laboratories Lead Length Life Measures Medical Messenger RNA Methods Microsatellite Repeats Monitor Mus Mutation Nature Neuraxis Neurons Pathogenesis Patients Pattern Pharmaceutical Preparations Phenotype Play Population Population Decreases Population Genetics Positioning Attribute Predisposition Pregnancy Property Proteins RNA RNA Splicing Regulation Role Seizures Slice Spices Structure Susceptibility Gene Synaptic Transmission Syndrome System Testing Time Transcript Translations Variant Work base behavior test case control family genetics frontal lobe gene cloning gene function genetic analysis genetic linkage analysis human data inhibitory neuron male member mouse model multidisciplinary neural circuit neuronal excitability promoter relating to nervous system research study response tissue culture young adult

项目摘要

DESCRIPTION (provided by applicant): Juvenile Myoclonic Epilepsy (JME) is a common epilepsy syndrome that starts in adolescence or young adulthood and requires lifelong treatment. BRD2 is a gene that, in some populations, is a causal factor in JME and in related electroencephalographic phenomena, which is demonstrated by replicated linkage and association studies. Based on family and population genetic analysis, it is currently the best candidate gene for a common epilepsy. This evidence is further strengthened by our studies of a Brd2 knockout mouse. The knockout data show that absence of BRD2 is incompatible with life. In heterozygote knockout mice (Brd2), the neural substrate is altered: there is a deficit of inhibitory neurons in two brain regions we have studied. Most compellingly, the heterozygotes show increased seizure susceptibility with a differential male/female pattern reminiscent of the pattern for JME in humans. We hypothesize that, in humans, mis- expression results in a slight insufficiency of BRD2 protein, leading to subtle changes in brain organization. Several lines of human imaging data report observing disruptions of neural substrate in JME patients, supporting the population genetic and mouse studies. We propose collaborative, multidisciplinary studies to determine the effect of altered BRD2 expression on brain substrate and function, and to identify the mechanisms by which such disturbances lead to brain hyperexcitability and seizures. Our aims are: 1) To fully characterize changes to the neural substrate, behavior, seizure susceptibility, and electrophysiology caused by insufficiency of murine Brd2 protein in Brd2 mice. This includes using brain- slice experiments to study the behavior of neural circuits in Brd2 mice compared to wild type, as well as investigating the responses of individual neurons. 2) To identify the specific change(s) in the expression of the human BRD2 gene that lead to brain hyperexcitability. We will express human BRD2 alleles associated with JME in tissue culture, study changes in their transcription, splicing, and translation, and correlate those changes with specific polymorphisms. We will examine polymorphisms in the BRD2 promoters, 3'UTR and 5'UTR, and other gene regions. In particular, we identified a highly conserved, alternately-spiced exon located in intron 2. We hypothesize that CA-repeat polymorphisms, found in intron 2 and associated with JME, affect the balance of alternatively spliced forms. New preliminary experiments show that the composition of the inter-exon DNA alters the splicing characteristics of the alternate exon. We will insert varying sizes of CA-repeat polymorphisms at that locus to observe the effect on levels of alternatively spliced BRD2 transcripts, eventually studying the fate of both the normal and alternately spliced RNA. PUBLIC HEALTH RELEVANCE: Project Narrative We propose to define the genetic, neuroanatomical, and circuitry mechanisms by which the gene BRD2 leads to susceptibility to Juvenile Myoclonic Epilepsy, a common epilepsy of adolescent onset and one that requires life-long medication to suppress seizures. The BRD2 gene, which we identified through studies of human epilepsy, has a profound effect on neural structure and circuitry. BRD2 is one of the few proven genes for a common epilepsy. This work could, at last, lead to understanding the basic cause and mechanism of an epilepsy that affects millions of Americans and places a difficult burden on the patient, their families, and the health care system.

描述（由申请人提供）：青少年肌阵挛性癫痫（JME）是一种常见的癫痫综合征，始于青春期或成年早期，需要终身治疗。 BRD2 基因在某些人群中是 JME 和相关脑电图现象的致病因素，这一点已通过重复连锁和关联研究得到证实。根据家族和人群遗传分析，它是目前常见癫痫病的最佳候选基因。我们对 Brd2 敲除小鼠的研究进一步强化了这一证据。敲除数据表明，缺乏 BRD2 与生命不相容。在杂合子基因敲除小鼠（Brd2）中，神经底物发生了改变：我们研究的两个大脑区域存在抑制性神经元的缺陷。最引人注目的是，杂合子表现出癫痫易感性增加，具有差异的男性/女性模式，让人想起人类的 JME 模式。我们假设，在人类中，错误表达会导致 BRD2 蛋白轻微不足，从而导致大脑组织发生微妙的变化。几行人体成像数据报告观察到 JME 患者神经基质的破坏，支持群体遗传和小鼠研究。我们建议进行多学科协作研究，以确定 BRD2 表达改变对大脑基质和功能的影响，并确定此类干扰导致大脑过度兴奋和癫痫发作的机制。我们的目标是：1) 全面表征 Brd2 小鼠中因鼠 Brd2 蛋白不足而引起的神经基质、行为、癫痫易感性和电生理学的变化。这包括使用脑切片实验来研究 Brd2 小鼠与野生型小鼠的神经回路行为，以及研究单个神经元的反应。 2) 确定导致大脑过度兴奋的人类 BRD2 基因表达的具体变化。我们将在组织培养中表达与 JME 相关的人类 BRD2 等位基因，研究其转录、剪接和翻译的变化，并将这些变化与特定的多态性相关联。我们将检查 BRD2 启动子、3'UTR 和 5'UTR 以及其他基因区域的多态性。特别是，我们鉴定了位于内含子 2 中的高度保守的交替香料外显子。我们假设在内含子 2 中发现并与 JME 相关的 CA 重复多态性影响可变剪接形式的平衡。新的初步实验表明，外显子间 DNA 的组成改变了替代外显子的剪接特征。我们将在该位点插入不同大小的 CA 重复多态性，以观察对选择性剪接 BRD2 转录本水平的影响，最终研究正常和选择性剪接 RNA 的命运。公共健康相关性：项目叙述我们建议定义 BRD2 基因导致青少年肌阵挛性癫痫易感性的遗传、神经解剖学和回路机制，青少年肌阵挛性癫痫是一种青少年发病的常见癫痫症，需要终生药物来抑制癫痫发作。我们通过对人类癫痫的研究发现了 BRD2 基因，它对神经结构和回路具有深远的影响。 BRD2 是少数已被证实的常见癫痫基因之一。这项工作最终可能有助于了解癫痫症的基本病因和机制，癫痫症影响着数百万美国人，并给患者、他们的家人和医疗保健系统带来了沉重的负担。