SODIUM CHANNEL REGULATION AND DISEASE

描述（由申请人提供）：癫痫是一种常见的异常神经元兴奋性疾病，对健康、智力和社会发展有长期影响。许多抗癫痫药物有不良的副作用，只针对癫痫的症状导致无效的癫痫控制。我们的长期目标是通过更好地了解影响神经元兴奋性的因素，促进更有效的癫痫治疗的发展。电压门控钠通道基因SCN1A突变是神经元兴奋性的关键调节因子，已在两种显性特发性全身性癫痫中发现：全身性癫痫伴发热性癫痫发作（GEFSP2）和婴儿期严重肌阵挛性癫痫（SMEI）。GEFSP2的特征是持续超过6岁的发热性（发热诱发）癫痫发作，并发展为成人癫痫。SMEI是一种严重的、使人衰弱的儿童癫痫，其特征是发热性和非热性癫痫发作、智力迟钝和共济失调。在SMEI患者中发现了许多功能丧失的SCN1A突变，这表明SCN1A表达水平与神经元兴奋性之间存在重要关系。我们假设关键SCN1A调控元件的序列变异也可以导致表达改变，并且代表了严重儿童癫痫的一个重要但尚未被探索的组成部分。我们将通过对患者和未受影响的对照组中发现的SCN1A启动子变异的功能分析来验证这一假设。通过多物种序列分析，我们在SCN1A基因中鉴定出9个进化上保守的非编码序列（> - 143 bp）。我们假设这些代表了额外的调节因素。这些区域的生物学功能将使用体外测定和小鼠靶向删除相结合的方法进行检查。为了进一步研究SCN1A表达与癫痫易感性之间的关系，我们将开发一系列内源性SCN1A表达水平为10-80%的小鼠系。这些表达水平将通过将具有良好特征的Scnla BAG转基因系与可用的杂合Scnla敲除小鼠杂交产生。这项研究将为SCN1A的调控和决定神经元兴奋性的机制提供新的、临床相关的见解。

DESCRIPTION (provided by applicant): Epilepsy is a common disorder of aberrant neuronal excitability that has long-term consequences for health and intellectual and social development. Many antiepileptic medications have undesirable side effects and only target the symptoms of epilepsy leading to ineffective seizure control. Our long-term goal is to facilitate the development of more effective epilepsy treatments through a better understanding of the factors that affect neuronal excitability. Mutations in the voltage-gated sodium channel gene SCN1A, a critical regulator of neuronal excitability, have been identified in two forms of dominant idiopathic generalized epilepsy: Generalized Epilepsy with Febrile Seizures Plus (GEFSP2) and Severe Myoclonic Epilepsy of Infancy (SMEI). GEFSP2 is characterized by febrile (fever induced) seizures that persist beyond the age of six and the development of adult epilepsy. SMEI is a severe, debilitating childhood epilepsy characterized by febrile and afebrile seizures, mental retardation and ataxia. Many loss-of-function SCN1A mutations have been identified in SMEI patients, suggesting an important relationship between SCN1A expression levels and neuronal excitability. We hypothesize that sequence variation in critical SCN1A regulatory elements can also lead to altered expression and represent an important, but as yet unexplored, component of severe childhood epilepsies. We will test this hypothesis by functional analysis of SCN1A promoter variants identified in patients and in unaffected controls. By multi-species sequence analysis, we have identified 9 evolutionarily conserved non-coding sequences (> 143 bp in length) in the SCN1A gene. We hypothesize that these represent additional regulatory elements. The biological functions of these regions will be examined using a combination of in vitro assays and by targeted deletion in the mouse. To further investigate the relationship between SCN1A expression and seizure susceptibility, we will develop a series of mouse lines with 10-80% of endogenous Scnla expression levels. These expression levels will be generated by crossing well-characterized Scnla BAG transgenic lines to available heterozygous Scnla knock-out mice. This study will provide new, clinically relevant insights into the regulation of SCN1A and the mechanisms that determine neuronal excitability.