Epigenetics of Down Syndrome

唐氏综合症的表观遗传学

• 批准号: 9977004
• 负责人: Benjamin Tycko
• 金额: $ 126.01万
• 依托单位: HACKENSACK UNIVERSITY MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-13 至 2022-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9977004
• 关键词: Address; Adult; Affect; Alleles; Alzheimer' s Disease; Aneuploidy; Architecture; Area; Autoimmunity; Autopsy; Bacterial Artificial Chromosomes; Binding Sites; Bioinformatics; Biological; Biological Assay; Biological Models; Brain; Cell Nucleus; Cells; Cerebrum; Chromatin; Chromosomal Duplication; Chromosomes; Critiques; DNA Methylation; Data; Development; Disease; Down Syndrome; Engineering; Epigenetic Process; Exhibits; Expression Profiling; Gene Dosage; Gene Expression; General Population; Genes; Genetic; Genetic Materials; Genetic Transcription; Genetic study; Genome; Genomics; Heart Abnormalities; Human; Individual; Intellectual functioning disability; Joints; Knock-out; Leukocytes; Life; Link; Lymphocyte; Malignant Neoplasms; Medical; Messenger RNA; Methylation; Modeling; Molecular; Mus; Mutation; Neuroglia; Neurons; Newborn Infant; Outcome; Paper; Pathogenesis; Pathway interactions; Pattern; Phenotype; Ploidies; Predisposition; Publishing; Quality of life; Recurrence; Research; Resistance; Shapes; Site; Specificity; Stains; Standardization; Syndrome; TF gene; Testing; Time; Tissues; Transgenes; Transgenic Model; Trisomy; Work; bisulfite sequencing; cell type; design; dosage; epigenetic profiling; epigenome; experimental study; fetal; gray matter; human tissue; improved; interstitial; mRNA Expression; methylation pattern; mouse Ts65Dn; mouse model; mutant; neoplastic; neuropsychiatric disorder; offspring; overexpression; response; success; transcription factor; transcriptome sequencing; whole genome

Achieving a better understanding of the pathogenesis of Down syndrome (DS; trisomy 21) is important for improving the quality of life of people with DS and for understanding major phenotypes, including intellectual disability, autoimmunity, cardiac defects, Alzheimer’s disease, and cancer susceptibility and resistance, which are prominent in DS and are also highly relevant to the general population. Recently we carried out epigenetic profiling, focusing on DNA methylation, in grey matter and purified neurons and glial cells from autopsy brains, as well as T-lymphocytes, from individuals with DS vs. matched normal controls. We found highly recurrent DS-specific differences in methylation patterns (DS-DM), and observed tissue-specificity of the DS-DM, onset of the altered methylation patterns at the fetal stage, and altered mRNA expression (DS-DE) of only a subset of the affected genes. We found that CpGs in specific classes of transcription factor binding sites (TFBS) were preferentially affected, implicating altered TFBS occupancy as a mechanism in shaping the patterns of DS-DM. Additionally, we carried out whole genome bisulfite sequencing (WGBS) on brains from mouse models of DS, compared to wild-type littermates, and found alterations in methylation patterns that significantly paralleled those in the human brains. Motivated by these findings, we now seek to answer three questions – all using well-controlled mouse models of DS carrying chromosomal triplications. First, to understand the molecular consequences of DS-DM we will identify DM genes in the mouse models and determine which of them have differential mRNA expression. We will address this question in purified cell types: T cells and GABAergic neurons. Second, we will test two hypotheses for the trans-acting mechanisms of DS-DM: (i) the abnormal methylation is due to over-expression of methylation pathway genes, including Dnmt3l and others, in the triplicated chromosome regions, and/or (ii) the abnormal patterns of methylation are shaped by overexpression of specific TF genes in the triplicated regions, leading to altered TFBS occupancy followed by altered CpG methylation in and around these sites. We will transfer segmental deletions and/or knockout alleles of individual genes into the DS mouse models to normalize gene dosage, and use WGBS and phenotyping to ask whether specific components of the DM and specific phenotypes are affected, respectively, in the offspring carrying the compound mutations. Third, we will apply state-of-the-art genomic assays to ask whether chromatin architecture within the cell nucleus is altered by the presence of the extra genetic material, and whether this alteration in turn affects DNA methylation, gene expression and phenotypes. Success of our project will identify effector and target genes for DS-DM and unravel the mechanisms underlying DS-DM. We expect that these data will significantly improve our understanding of DS pathogenesis and have broad implications for trans-acting genetic epigenetic interactions in other human developmental and neoplastic disorders that are associated with chromosomal aneuploidies.

更好地了解唐氏综合症的发病机理（DS；三体术21）对于 改善DS患者的生活质量和理解主要表型，包括智力 残疾，自身免疫，心脏缺陷，阿尔茨海默氏病以及癌症的敏感性和抗药性，这 在DS中很突出，并且与普通人群高度相关。最近我们进行了表观遗传学 分析，侧重于DNA甲基化，灰质和纯化的神经元和神经胶质细胞，尸检大脑中的神经胶质细胞， 以及T-Lymphocytes，来自具有DS与匹配的正常对照的个体。我们发现高度反复出现 DS特异性甲基化模式（DS-DM）和DS-DM开始观察到的组织特异性的差异 在胎儿阶段改变的甲基化模式，并仅改变子集的mRNA表达（DS-DE） 受影响的基因。我们发现，特定类别的转录因子结合位点（TFB）中的CPG为 优先影响，隐式改变了TFBS占用率，作为塑造DS-DM模式的一种机制。 此外，我们对DS小鼠模型的大脑进行了整个基因组Bisulfite测序（WGB）， 与野生型窝窝相比，发现甲基化模式的变化显着平行 那些在人类大脑中的人。在这些发现的激励下，我们现在寻求回答三个问题 - 所有问题都使用 携带染色体三重三分之一的DS的良好控制的小鼠模型。首先，了解分子 DS-DM的后果我们将在鼠标模型中识别DM基因，并确定其中哪些具有 差异mRNA表达。我们将在纯化的细胞类型中解决这个问题：T细胞和GABA能 神经元。其次，我们将测试两个假设的DS-DM的跨作用机理：（i）异常 甲基化是由于甲基化途径基因的过表达，包括DNMT3L等 三式染色体区域和/或（ii）甲基化的异常模式是通过过表达形成的 三分之一区域中特定的TF基因的特定基因，导致TFBS的占用率改变，随后CPG改变了 这些地点及其周围的甲基化。我们将转移分段删除和/或淘汰等位基因 单个基因进入DS小鼠模型以使基因剂量归一化，并使用WGB和表型提出 在后代中，DM和特定表型的特定组件是否分别受到影响 携带复合突变。第三，我们将应用最先进的基因组问题来询问是否是否 细胞核内的染色质结构因额外的遗传物质的存在而改变，并且 这种改变反过来会影响DNA甲基化，基因表达和表型。我们的成功 项目将识别DS-DM的效应子和靶基因，并阐明DS-DM的机制。我们 预期这些数据将显着提高我们对DS发病机理的理解，并具有广泛的 对其他人类发育和肿瘤的反式遗传表观遗传相互作用的影响 与染色体非整倍性相关的疾病。