Isogenic Pairs of Wild Type and Mutant Induced Pluripotent Stem Cell (iPSC) Lines from Rett Syndrome Patients as In Vitro Disease Model

Rett syndrome (RTT) is an autism spectrum developmental disorder caused by mutations in the X-linked methyl-CpG binding protein 2 (MECP2) gene. Excellent RTT mouse models have been created to study the disease mechanisms, leading to many important findings with potential therapeutic implications. These include the identification of many MeCP2 target genes, better understanding of the neurobiological consequences of the loss- or mis-function of MeCP2, and drug testing in RTT mice and clinical trials in human RTT patients. However, because of potential differences in the underlying biology between humans and common research animals, there is a need to establish cell culture-based human models for studying disease mechanisms to validate and expand the knowledge acquired in animal models. Taking advantage of the nonrandom pattern of X chromosome inactivation in female induced pluripotent stem cells (iPSC), we have generated isogenic pairs of wild type and mutant iPSC lines from several female RTT patients with common and rare RTT mutations. R294X (arginine 294 to stop codon) is a common mutation carried by 5–6% of RTT patients. iPSCs carrying the R294X mutation has not been studied. We differentiated three R294X iPSC lines and their isogenic wild type control iPSC into neurons with high efficiency and consistency, and observed characteristic RTT pathology in R294X neurons. These isogenic iPSC lines provide unique resources to the RTT research community for studying disease pathology, screening for novel drugs, and testing toxicology.雷特综合征（Rett syndrome, RTT）是一类由X连锁甲基CpG结合蛋白2（MECP2）基因突变引发的自闭症谱系发育障碍性疾病。科研人员已构建出优质的RTT小鼠模型用于疾病机制研究，取得了多项具备潜在治疗价值的重要发现，包括鉴定出大量MeCP2靶基因、更深入阐明MeCP2功能缺失或异常的神经生物学后果，以及在RTT小鼠中开展药物测试、在人类RTT患者中推进临床试验。然而，由于人类与常见实验动物的基础生物学特性可能存在差异，亟需建立基于细胞培养的人类疾病模型，以验证和拓展动物模型中获取的研究成果。本研究借助女性诱导多能干细胞（induced pluripotent stem cells, iPSC）中X染色体失活的非随机模式，从多名携带常见与罕见RTT突变的女性RTT患者体内，成功构建了野生型与突变型iPSC细胞系的同基因对。其中，R294X（精氨酸294突变为终止密码子）是一种常见突变，约占RTT患者的5%~6%，但目前尚未有针对携带该突变的iPSC的相关研究报道。我们高效且稳定地将3株R294X突变型iPSC及其同基因野生型对照iPSC分化为神经元，并在R294X神经元中观察到了特征性的RTT病理表型。上述同基因iPSC细胞系可为RTT研究领域提供独特的研究资源，用于疾病病理机制研究、新型药物筛选以及毒理学测试。