唐氏综合征患者iPSCs基因组DNA甲基化异常模式的分析和验证  

Genome-wide analysis of aberrant DNA methylation patterns in iPSCs derived from patients with Down syndrome

作　　者：马文博 刘艳娜 颜景斌 Ma Wenbo;Liu Yanna;Yan Jingbin(Shanghai Institute of Medical Genetics,Shanghai Children’s Hospital,Shanghai Jiaotong University School of Medicine,Shanghai 200040,China;NHC Key Laboratory of Medical Embryogenesis and Developmental Molecular Biology,Shanghai Key Laboratory of Embryo and Reproduction Engineering,Shanghai 200040,China)

机构地区：[1]上海市儿童医院,上海医学遗传研究所,上海交通大学医学院,上海交通大学附属儿童医院200040 [2]国家卫健委医学胚胎分子生物学重点实验室,上海市胚胎与生殖工程重点实验室200040

出　　处：《中华医学遗传学杂志》2021年第6期531-535,共5页Chinese Journal of Medical Genetics

基　　金：国家重点研发计划(2016YFC1000503,2019YFA0801402);国家自然科学基金(81971421,81471485)。

摘　　要：目的探讨唐氏综合征(Down syndrome,DS)DNA甲基化模式以及基因不同元件甲基化水平与DS基因表达的相关性。方法应用全基因组亚硫酸氢盐测序技术筛选来源于DS患儿和正常对照的诱导多功能干细胞(induced pluripotent stem cells,iPSCs)中差异甲基化区域(differentially methylated region,DMR),对其在染色体和基因位置上的分布进行统计分析。通过聚类分析,研究差异基因涉及的功能。并结合全基因组表达谱数据和实时荧光定量PCR(quantitative real-time PCR,qRT-PCR)研究不同基因元件甲基化的调控作用。结果DS iPSCs中共检测出1569个DMR,启动子区高甲基化所占比例明显高于基因体(genebody),且DMR不富集在21号染色体上。启动子和genebody高甲基化均对基因表达起到抑制作用。聚类结果显示,具有DMR的基因显著富集在神经发育、干细胞多能性以及组织器官大小调控的相关通路上。结论DS iPSCs中DNA甲基化异常在全基因组广泛分布,DS中DNA甲基化的分布模式和调控模式均不同于正常样本,DNA甲基化可能在早期胚胎发育过程中参与了唐氏综合征DS患者神经发育异常及其他异常的发生。Objective To study the correlation between DNA methylation patterns and gene expression in Down syndrome(DS).Methods Induced pluripotent stem cells(iPSCs)derived from normal controls and DS patients were subjected to whole genome bisulfite sequencing and differentially methylated region(DMR)screening.Statistical analysis for chromosomal and gene element distribution were carried out for DMR.Gene ontology(GO)and enrichment-based cluster analysis were used to explore the molecular function of differentially expressed genes.Results A total of 1569 DMR were identified in iPSCs derived from DS patients,for which the proportion of hypermethylation in promoter regions was significantly greater than that of the genebody.No DMR enrichment was noted on chromosome 21.Hypermethylation of the promoter and genebody was predicted to be inhibitory for gene expression.Functional clustering revealed the pathways related to neurodevelopmental,stem cell pluripotency and organ size regulation to be significantly correlated with differentially methylated genes.Conclusion Extensive and stochastic anomalies of genome-wide DNA methylation has been discovered in iPSCs derived from DS patients,for which the pattern and molecular regulation of methylation were significantly different from those of normal controls.Above findings suggested that DNA methylation pattern may play a vital role in both the pathogenesis of neurodevelopmental disorders and other phenotypic abnormalities during early embryonic development.

关 键 词：诱导多功能干细胞 唐氏综合征 DNA甲基化 高甲基化 差异甲基化区域 异常模式 神经发育 多能性 

分 类 号：R714.5[医药卫生—妇产科学]