Lu Ping, Chen Xiaolong, Feng Yun, Zeng Qiao, Jiang Cizhong, Zhu Xianmin, Fan Guoping, Xue Zhigang
Tongji Stem Cell Research Center, Tongji University School of Medicine, Shanghai, 200092, China.
Tongji University, School of Life Sciences and Technology, Shanghai, 200092, China.
Sci China Life Sci. 2016 Nov;59(11):1093-1105. doi: 10.1007/s11427-016-0194-6. Epub 2016 Oct 11.
Fragile X syndrome (FXS) patients carry the expansion of over 200 CGG repeats at the promoter of fragile X mental retardation 1 (FMR1), leading to decreased or absent expression of its encoded fragile X mental retardation protein (FMRP). However, the global transcriptional alteration by FMRP deficiency has not been well characterized at single nucleotide resolution, i.e., RNA-seq. Here, we performed in-vitro neuronal differentiation of human induced pluripotent stem (iPS) cells that were derived from fibroblasts of a FXS patient (FXS-iPSC). We then performed RNA-seq and examined the transcriptional misregulation at each intermediate stage during in-vitro differentiation of FXS-iPSC into neurons. After thoroughly analyzing the transcriptomic data and integrating them with those from other platforms, we found up-regulation of many genes encoding TFs for neuronal differentiation (WNT1, BMP4, POU3F4, TFAP2C, and PAX3), down-regulation of potassium channels (KCNA1, KCNC3, KCNG2, KCNIP4, KCNJ3, KCNK9, and KCNT1) and altered temporal regulation of SHANK1 and NNAT in FXS-iPSC derived neurons, indicating impaired neuronal differentiation and function in FXS patients. In conclusion, we demonstrated that the FMRP deficiency in FXS patients has significant impact on the gene expression patterns during development, which will help to discover potential targeting candidates for the cure of FXS symptoms.
脆性X综合征（FXS）患者在脆性X智力低下1（FMR1）基因启动子区域携带超过200个CGG重复序列的扩增，导致其编码的脆性X智力低下蛋白（FMRP）表达减少或缺失。然而，FMRP缺陷引起的全基因组转录改变在单核苷酸分辨率水平上，即RNA测序，尚未得到很好的表征。在此，我们对源自一名FXS患者成纤维细胞的人诱导多能干细胞（iPS）进行了体外神经元分化（FXS-iPSC）。然后我们进行了RNA测序，并检查了FXS-iPSC在体外分化为神经元的每个中间阶段的转录失调情况。在对转录组数据进行全面分析并将其与其他平台的数据整合后，我们发现许多编码神经元分化转录因子（WNT1、BMP4、POU3F4、TFAP2C和PAX3）的基因上调，钾通道（KCNA1、KCNC3、KCNG2、KCNIP4、KCNJ3、KCNK9和KCNT1）下调，并且在FXS-iPSC衍生的神经元中SHANK1和NNAT的时间调控发生改变，这表明FXS患者的神经元分化和功能受损。总之，我们证明了FXS患者中FMRP缺陷对发育过程中的基因表达模式有显著影响，这将有助于发现治疗FXS症状的潜在靶向候选药物。
