Delineating a role for histone modifications in Down syndrome using human cellular models

使用人类细胞模型描述组蛋白修饰在唐氏综合症中的作用

• 批准号: 10595812
• 负责人: Lindy Elise Barrett
• 金额: $ 28.5万
• 依托单位: BROAD INSTITUTE, INC.
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10595812
• 关键词: Aberrant DNA Methylation; Area; Automobile Driving; Blood Cells; CRISPR-mediated transcriptional activation; Cell Line; Cell model; Cells; Chromosome 21; DNA; DNA Maintenance; DNA Methylation; Data; Data Set; Development; Disease; Down Syndrome; Epigenetic Process; Euchromatin; Future; Gene Expression; Genes; Genetic Transcription; Glutamates; Histone H3; Human; Human Development; Immunoprecipitation; Induced pluripotent stem cell derived neurons; Intercistronic Region; Investigation; Lysine; Maps; Methylation; Molecular; Molecular Analysis; Neurodevelopmental Disorder; Neurons; Oncology; Pathway interactions; Patients; Pattern; Peripheral; Pharmacology; Phenotype; Physiological; Reader; Reporting; Reproducibility; Role; Sampling; Sotos syndrome; System; Testing; Tissues; Transcript; Transcriptional Regulation; Up-Regulation; base; cell type; clinically relevant; design; experimental study; fetal; genome-wide; histone demethylase; histone methyltransferase; histone modification; induced pluripotent stem cell; inhibitor; lymphoblastoid cell line; methylation pattern; novel; novel therapeutic intervention; novel therapeutics; recruit; stem cell model; therapeutic development

SUMMARY Down syndrome (DS), driven by an extra copy of chromosome 21, is associated with profound changes in genome-wide gene expression and DNA methylation, but underlying mechanisms remain incompletely resolved. Leveraging human induced pluripotent stem cell (iPSC) models to capture molecular mechanisms relevant for human development, we previously identified a significant decrease in the abundance of a specific histone modification, histone H3 lysine 36 dimethylation (H3K36me2), in DS patient cells compared with euploid controls; this finding was also highly reproducible across a panel of DS patient and euploid control lymphoblastoid cell lines, indicating the finding extends to some peripheral cell types. H3K36me2 is localized to euchromatin where it impacts transcriptional regulation and is essential for maintenance of DNA methylation via DNMT3A recruitment, particularly at intergenic regions. Notably, haploinsufficiency of the histone methyltransferase which catalyzes H3K36me2 drives a neurodevelopmental disorder called Sotos syndrome, characterized by reduced H3K36me2, transcriptional dysregulation and DNA hypomethylation. The profound developmental consequences of reduced H3K36me2 in Sotos syndrome supports the novel hypothesis that the reduced H3K36me2 we found in DS could also contribute to developmental abnormalities in this disease context. Our overall hypothesis is that reduced H3K36me2 in DS drives DNA hypomethylation and transcriptional dysregulation, and that normalization of H3K36me2 will partially rescue these phenotypes. In Aim I, we will test the hypothesis that decreased H3K36me2 drives DNA hypomethylation in DS, by generating genome-wide DNA methylation maps and integrating them with existing H3K36me2 gene occupancy and transcriptional datasets, all from the same DS patient and isogenic euploid control iPSC- derived glutamatergic neurons. Importantly, these experiments are designed to connect a well-characterized phenotype in DS (aberrant DNA methylation) with a novel molecular mechanism (reduced H3K36me2). In Aim II, we will test the hypothesis that normalizing H3K36me2 levels in DS patient iPSC-derived neurons can rescue DNA methylation phenotypes. These data would serve as proof-of-principle that inhibition or activation of specific epigenetic modifiers can reverse well-characterized phenotypes in DS, using physiologically relevant human cellular models. Collectively, our rigorous molecular analyses will elucidate novel mechanisms of epigenetic dysregulation in DS, which may ultimately inform on new therapeutic strategies for DS patients; they will also generate an essential roadmap for future studies to further investigate how reduced H3K36me2 and its normalization impacts iPSC-derived and peripheral blood cell phenotypes.

概括 唐氏综合症（DS），由21号染色体的额外副本驱动，与深刻的变化有关 全基因组基因表达和DNA甲基化，但潜在的机制保持不完全 解决。利用人类诱导的多能干细胞（IPSC）模型捕获分子机制 与人类发展相关，我们先前确定了特定的丰度显着下降 组蛋白修饰，组蛋白H3赖氨酸36二甲基化（H3K36ME2），与DS患者细胞相比 整倍体控制；在DS患者和eploid Control的面板中，这一发现也可以高度重现 淋巴细胞细胞系，表明该发现扩展到某些外围细胞类型。 H3K36Me2本地化为 构象素影响转录调节，对于维持DNA甲基化至关重要 通过DNMT3A招募，特别是在基因间区域。值得注意的是，组蛋白的单倍不足 催化H3K36ME2的甲基转移酶驱动一种称为SOTOS综合征的神经发育障碍， 特征在于H3K36ME2降低，转录失调和DNA低甲基化。深刻 Sotos综合征中H3K36ME2降低的发育后果支持了以下新假设 我们在DS中发现的降低的H3K36ME2也可能导致该疾病的发育异常 语境。我们的总体假设是，DS中H3K36me2的降低驱动DNA低甲基化和 转录失调，H3K36ME2的归一化将部分拯救这些 表型。在目标I中，我们将测试降低H3K36ME2的假设，驱动DNA降低了DNA降甲基化 DS，通过生成全基因组DNA甲基化图并将其与现有的H3K36ME2基因集成 占用和转录数据集，所有这些都来自同一DS患者和等源性的Euploid Control IPSC- 衍生的谷氨酸能神经元。重要的是，这些实验旨在连接一个特征良好的 具有新型分子机制（降低H3K36me2）的DS（异常DNA甲基化）中的表型。目标 II，我们将测试以下假设：DS患者IPSC衍生的神经元中H3K36ME2水平正常 拯救DNA甲基化表型。这些数据将作为抑制或激活的原理证明 特定的表观遗传修饰剂可以使用生理学上的DS中逆转良好的表型 相关的人类细胞模型。总体而言，我们严格的分子分析将阐明新机制 DS的表观遗传失调，最终可能会为DS患者提供新的治疗策略； 他们还将为未来的研究生成必不可少的路线图，以进一步研究如何减少H3K36ME2 它的归一化影响IPSC衍生和外周血细胞表型。