基于脆性X染色体综合症iPSC细胞模型的神经发育异常的机制研究和药物筛选

Fragile X syndrome (FXS) is an X chromosome-linked genetic disorders. Its main clinical manifestations are severe mental retardation, facial deformity, attention deficit hyperactivity disorder, aggressive behavior or autism. In males, the incidence is 1/1500, only less than Down's syndrome incidence. The main pathogenic cause is the methylation occupied FMR1 gene promoter region which leads to gene silencing then leads to patients with mental retardation. There is no effective therapy to cure the disease till today. The establishment of induced pluripotent stem cells (iPSC) technology and in vitro directed induced differentiation technology provide a convenience for the study of disease pathogenesis and drug screening. We have established the cell model of FXS based on the iPSC technology and found the function of neurons differentiation from FXS-iPSC was decreased significantly. On the basis of electrophysiology, living cell imaging and gene expression profiling analysis, we will investigate the phenotypic changes of neurodevelopmental abnormalities of morphology, structure and function of FXS neuron to reveal the reasons for causing cell phenotype change and to explore the mechanisms of mGluR5 antagonists to repair the FXS neron neurodevelopmental abnormalities. All this work will provide new ideas and methods for the clinical FXS treatment.

脆性X染色体综合症（FXS）是X染色体连锁的一种最常见遗传病，其临床表现主要中、重度智力低下，面部畸形，一些患者还有多动症，攻击性行为或孤独症，在男性中的发病率为1/1500，仅次于先天愚型；其致病原因主要是其致病基因FMR1启动子区域的甲基化导致基因沉默，从而导致患者智力低下，目前尚无有效治疗药物。诱导多能干细胞(iPSC)技术的诞生和特异性定向诱导分化技术的建立为体外研究疾病发病机制和药物筛选提供了方便。我们前期利用iPSC技术，已经建立了FXS的细胞模型，并在分化中发现其分化成神经元细胞的功能明显下降；本研究将在证实前期试验的基础上，采用电生理、活细胞成像以及基因表达谱分析的方法，研究FXS神经元的形态、结构、功能和神经网络等神经发育异常的表型变化，揭示引起细胞表型变化的原因；并探讨mGluR5拮抗剂修复FXS神经元发育异常的机制，为临床FXS的治疗提供新的思路和方法。

脆性X染色体综合症（Fragile X syndrome，FXS）是X染色体连锁的最常见的一种遗传性弱智疾病。FMR1基因的CGG重复序列高度甲基化的表观遗传学变化引起其编码的智力迟钝蛋白（FMRP）不表达或低表达，并最终导致FXS。目前尚无有效治疗药物。诱导多能干细胞(induced pluripotent stem cell, iPSC)和疾病相关细胞定向诱导分化技术的建立为体外研究疾病发病机制，寻找治疗靶点和高通量药物筛选带来曙光。本项目已经采用iPSC技术建立FXS-iPSC，将其定向诱导分化为FXS神经元；综合运用RT-PCR、免疫荧光染色、基因表达谱分析等方法，研究了FXS神经元的形态、结构、功能和神经网络等神经发育异常的表型变化。这将为揭示引起FXS细胞表型变化的原因提供理论基础；并能借助培养的FXS神经元，探讨mGluR5拮抗剂修复FXS神经元发育异常的机制，为临床FXS的治疗提供思路和方法。