DEPDC5基因突变与新生儿特发性惊厥的分子机制研究

Neonatal seizure is one of the most common manifestations of neurological disorders in the newborn period and have engendered significant study and debate among neurologists. Despite marked advances in neonatal seizures research and clinical care in recent decades, the etiology of idiopathic cases still is poor understood. Genetics is believed to have an important role in newborns with idiopathic seizures. On the basis of our previous research works, we found a nonsense mutation in DEPDC5 gene in a newborn with idiopathic seizure using whole exome sequencing. This gene encodes DEP Domain Containing 5, as a component of the GATOR1 complex, inhibitor of the amino acid-sensing branch of the TORC1 pathway. We intended to study the role of DEPDC5 gene mutation on the development of seizures. In this study: 1. We will analyze the copy number variants and sequence variants of coding regions for DEPDC5 gene using real-time PCR and Sanger sequencing in 80-100 patients with idiopathic neonatal seizures; 2. Get the fibroblasts from the patient with DEPDC5 gene mutations, and induced the fibroblasts into pluripotent stem cells, and then further induced into neurons. Neuronal morphology and electrophysiological characteristics, the efects on TORC1 singaling and GATOR-1 complex formation, and the therapeutic effect of rapamycin will be investigated. 3. Using DEPDC5 gene mutant zebersifh model, we will analyse the electrophysiological characteristics of neurons, the TORC1 singaling and GATOR-1 complex formation, and investigate the therapeutic effect of rapamycin. The purpose of this study is to clarify DEPDC5 gene mutant effects on neurons and mechanism involved, and to provide a novel therapeutic target.

惊厥是新生儿最常见的神经系统急症，2%~5%为原因不明的新生儿特发惊厥。遗传因素可能是导致新生儿特发惊厥的主要原因。课题组通过全外显子组测序，在1例新生儿特发惊厥患儿检测到DEPDC5基因终止突变，导致了蛋白质的大段缺失。DEPDC5在2013年才首次在家族性局灶性癫痫患者检测到，但是尚缺乏深入机制研究及药物治疗靶点的探索。因此本课题拟（1）分析DEPDC5基因在新生儿特发性惊厥中的突变谱；（2）通过患儿体细胞诱导iPS分化神经元，观察DEPDC5基因突变对神经元电生理特征、mTOR通路表达水平的影响；（3）构建DEPDC5基因突变斑马鱼模型，进行行为学分析、机制研究及治疗探索。以期阐明DEPDC5基因在新生儿特发性惊厥中的作用机制，并进一步探索新的药物治疗靶点。

惊厥是新生儿最常见的神经系统急症，2%~5%为原因不明的新生儿特发惊厥。遗传因素可能是导致新生儿特发惊厥的主要原因。DEPDC5在2013年才首次在家族性局灶性癫痫患者检测到，但是尚缺乏深入机制研究，及药物治疗靶点的探索。本研究建立了携带DEPDC5基因致病/可疑致病变异的专病样本-数据库，得到DEPDC5基因突变在我院较大样本的新生儿惊厥患儿中的基因型及突变谱。并采用体外培养小鼠原代神经元，敲减Depdc5基因表达，初步探讨DEPDC5基因对神经元发育和功能的作用，发现敲减Depdc5可导致小鼠神经元轴突异常生长。阐明DEPDC5基因在新生儿特发性惊厥中的可能作用机制。发表标注受本项目资助的SCI文章1篇，影响因子8.683。