Cross-species modeling of epileptogenesis in KCNT1-associated epilepsy

项目总结 癫痫是最常见的儿童神经系统疾病之一，在中国每10万名儿童中就有40名儿童患有癫痫 只有我们两个。在一岁之前癫痫发作的儿童早期死亡率增加六倍，部分原因是 对常规抗惊厥药物的反应不成比例地差。基因检测的可用性已经 极大地改善了早发性癫痫的病因诊断，因为现在约26%的早期癫痫是 与各种基因的致病基因突变有关，如离子通道。然而，准确地说- 有针对性的治疗选择仍然有限。KCNT1基因的错义致病变异体 钠激活钾通道是约40%的严重婴儿发作性癫痫的病因 称为婴儿期癫痫伴迁移性局灶性癫痫(EIMFS)，提示有强烈的基因-表型 两性关系。由于EIMFS的一个特征是药物难治性癫痫发作，针对其发病机制是一种 新的抗惊厥药物干预的机会。拟议研究的目标是界定 导致EIMFS癫痫发作的病理生理机制，以便合理地进行抗惊厥治疗 在病程早期选择和应用。目标1描述了管理DEC的细胞机制 从患者来源的诱导多能性分化的人类神经元中的Novo KCNT1功能增益变异体 干细胞(IPSCs)。我们假设KCNT1通道动力学改变会导致持续性增加 钾电流，损害抑制性神经元的高频放电。AIM 2结合了详细的表型分析 用标记中间神经元急性切片电生理学建立KCNT1相关性癫痫小鼠模型 亚群。我们假设，海马区中间神经元将受到不同的-增益- Kcnt1功能敲入变异体，表现为动作电位激发减少，其结果是Pre-Net减少 突触GABA释放和兴奋性神经元过度爆发。综上所述，这些研究将拓宽 我们对KCNT1突变在白血病发病机制中的细胞机制的理解 严重的儿童癫痫，为开发EIMFS的精确药物疗法奠定了基础。 特蕾西·格特勒，医学博士，博士，儿童神经学博士，K08职业发展奖申请表 鲁里儿童医院的讲师。成为离子领域的独立内科医生和科学家 通过生理学和神经遗传学，Gertler博士将把她的大部分医学后培训投入到 离子通道病所致遗传性癫痫的研究。儿科神经科的分科 儿科对求职者的职业发展有着坚定不移的承诺，因为她 利用她的神经生理学背景，并增加了应用干细胞生物学和基因- 小阿尔弗雷德·L·乔治博士指导下的癫痫动物模型的编辑和表型分析。和 詹妮弗·科尔尼。

Project summary Epilepsy is among the most common childhood neurologic disorders, affecting 40 children per 100,000 in the US alone. Children with seizure onset before age one have a six-fold increase in early mortality, due in part to a disproportionately poor response to conventional anticonvulsants. The availability of genetic testing has dramatically improved etiologic diagnoses of early-onset epilepsy, as ~26% of early-life epilepsy is now associated with pathogenic genetic mutations in a variety of genes such as ion channels. Yet, precisely- targeted therapeutic options remain limited. Missense pathogenic variants in KCNT1, a gene encoding a sodium-activated potassium channel, are causative for ~ 40% of cases of a severe infantile-onset epilepsy called epilepsy of infancy with migrating focal seizures (EIMFS), suggestive of a strong genotype-phenotype relationship. As a hallmark of EIMFS is medically-refractory seizures, targeting its pathogenic mechanism is an opportunity for novel anticonvulsant intervention. The goal of the proposed studies is to define the pathophysiologic mechanisms that lead to seizures in EIMFS so that anticonvulsant therapies can be rationally chosen and applied early in the disease course. Aim 1 delineates the cellular mechanisms governing a de novo KCNT1 gain-of-function variant in human neurons differentiated from patient-derived induced pluripotent stem cells (iPSCs). We hypothesize that altered KCNT1 channel kinetics result in increased persistent potassium current, impairing high-frequency firing of inhibitory neurons. Aim 2 combines detailed phenotyping of a mouse model of KCNT1-associated epilepsy with acute slice electrophysiology of labeled interneuron subpopulations. We hypothesize that hippocampal interneurons will be differentially affected by a gain-of- function Kcnt1 knock-in variant, evidenced by decreased action potential firing, with resultant decreased pre- synaptic GABA release and excessive excitatory neuron bursting. Taken together, these studies will broaden our understanding of the cellular mechanisms by which KCNT1 mutations contribute to the pathogenesis of severe childhood epilepsy, laying the groundwork for development of precise pharmacotherapies for EIMFS. This application is for a K08 Career Development Award for Tracy Gertler, M.D., Ph.D., Child Neurology Instructor at Lurie Children’s Hospital. To become an independent physician-scientist in the fields of ion channel physiology and neurogenetics, Dr. Gertler will commit the majority of her post-medical training to research in genetic epilepsy due to ion channelopathies. The division of pediatric neurology within the pediatrics department has an unwavering commitment to the career development of the candidate as she takes advantage of her neurophysiology background and adds training in applied stem cell biology and gene- editing and phenotyping of animal models of epilepsy under the mentorship of Drs. Alfred L. George, Jr. and Jennifer Kearney.