Aberrant chromatin regulatory mechanisms in Down syndrome brain

唐氏综合症大脑中异常的染色质调节机制

• 批准号: 10665587
• 负责人: Ian S. Maze
• 金额: $ 35.3万
• 依托单位: ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-15 至 2024-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10665587
• 关键词: Adult; Affect; Affinity; Aneuploidy; Animals; Bar Codes; Behavioral; Binding; Binding Proteins; Biochemical; Biological Assay; Biophysics; Brain; Brain region; Bromodomain; Cell Separation; Characteristics; Chromatin; Chromatin Remodeling Factor; Chromosome 21; Chromosome abnormality; Clustered Regularly Interspaced Short Palindromic Repeats; Code; Cognition; Cognitive; Cognitive deficits; Complex; Coupled; DNA; Data; Deposition; Disease; Dorsal; Down Syndrome; Electrophysiology (science); Embryo; Epigenetic Process; Female; Functional disorder; Gene Expression; Gene Expression Profiling; Genes; Genetic; Genetic Transcription; Growth; Hippocampus; Histones; Human; Impaired cognition; Impairment; In Vitro; Incidence; Intellectual functioning disability; Investigation; Laboratories; Lead; Libraries; Live Birth; Mass Spectrum Analysis; Mediating; Mediation; Methodology; Molecular; Molecular Abnormality; Mus; Neuroglia; Neurologic; Neurons; Nucleosomes; Outcome; Pathway interactions; Pattern; Physiological; Play; Post-Translational Protein Processing; Process; Proteins; Proteomics; Reader; Regulation; Rodent Model; Role; SMARCA4 gene; Sampling; Shapes; Structure; Synapses; Synaptic plasticity; Syndrome; Testing; Transcription Coactivator; Trisomy; Validation; Viral; WD Repeat; age group; cell type; cognitive disability; combinatorial; dosage; epigenome; epigenomics; experimental study; gene network; genome-wide; in vivo; induced pluripotent stem cell; liquid chromatography mass spectrometry; male; member; mouse Ts65Dn; mouse model; nano-liquid chromatography; neural; neurodevelopment; novel; overexpression; permissiveness; recruit; skeletal abnormality; spatial memory; transcriptome; transcriptome sequencing

Project Summary: Maze I ! Down syndrome (DS) is the most common genetic cause of intellectual disability worldwide resulting from triplication of chromosome 21 (HSA21) in humans. Despite much progress in understanding the genetics of DS, the genes encoded on HSA21–and beyond–that directly contribute to intellectual disability, as well as their associated molecular mechanisms, remain incompletely understood. BRWD1 is an uncharacterized, brain enriched chromatin `reader' protein encoded within the DS critical region 2 on HSA21. BRWD1 is believed to act as a transcriptional activator via its proposed interactions with the SWI/SNF chromatin remodeling complex; however, its roles in the contexts of neurodevelopment and in DS have yet to be studied. Consistent with previous gene expression analyses in human DS brain, we observe that Brwd1 expression is significantly elevated in trisomic mice, as well as in neurons derived from hiPSCs from DS subjects. Select histone posttranslational modifications (PTMs), some of which we have already shown to directly interact with BRWD1, are also altered in their expression. We have demonstrated that genetic re-normalization of Brwd1 expression in Ts65Dn mice significantly rescues transcriptional dysplasticity associated with hippocampal LTP and cognitive deficits in trisomic animals. Furthermore, exogenous Brwd1 overexpression–via viral-mediated transduction of adult dorsal hippocampal neurons in wildtype animals–also leads to deficits in both contextual and spatial memory. It is our hypothesis that BRWD1 trisomy in DS brain results in aberrant interactions between BRWD1 and the epigenetic landscape, thereby contributing to global gene expression abnormalities and cognitive deficits. We seek to test this hypothesis in the following independent, yet synergistic Aims: 1) Examine the relationship between Brwd1 trisomy and chromatin dysfunction in DS-like brain, with an overarching emphasis on a) unbiased assessments of histone PTM expression in DS-like neurons and glia (+/– Brwd1 rescue) using cell sorting methodologies coupled to histone PTM mass spectrometry, and b) delineation of direct interactions between BRWD1 and altered histone PTMs using highly novel `designer' nucleosome-based assays and in vivo validations. 2) Investigate the impact of Brwd1 triplication on gene expression in DS-like brain. We aim to perform unbiased, epigenome-wide analyses of Brwd1 enrichment–along with associated histone PTMs–in Ts65Dn brain, followed by extensive comparisons with gene expression profiles obtained using cell-type specific RNA-seq. CRISPR-based manipulations will subsequently be performed to directly assess Brwd1 target gene contributions to observed behavioral abnormalities. 3) Explore the impact of Brwd1 triplication on recruitment/activity of specific SWI/SNF chromatin remodeling complexes in Ts65Dn mouse brain using biochemical and genome-wide assessments. These experiments will allow us to dissect the functional consequences of abnormal patterns of chromatin regulation in DS brain and will aid in our understanding of the neuroepigenetic processes associated with brain plasticity.

项目概要：迷宫 I ！ 唐氏综合症（DS）是全世界智力障碍最常见的遗传原因，其原因是 人类 21 号染色体 (HSA21) 的三倍体。尽管在理解遗传学方面取得了很大进展 DS，编码在 HSA21 及其他基因上的基因，直接导致智力障碍，以及它们的基因 相关的分子机制仍不完全清楚。 BRWD1 是一个未表征的大脑 HSA21 上 DS 关键区域 2 内编码的富集染色质“阅读器”蛋白。 BRWD1被认为 通过与 SWI/SNF 染色质重塑复合物的相互作用，充当转录激活剂； 然而，它在神经发育和 DS 中的作用仍有待研究。符合 在之前的人类 DS 大脑基因表达分析中，我们观察到 Brwd1 表达显着 在三体小鼠以及来自 DS 受试者 hiPSC 的神经元中升高。选择组蛋白 翻译后修饰 (PTM)，我们已经证明其中一些可以直接与 BRWD1 相互作用， 他们的表情也发生了变化。我们已经证明 Brwd1 表达的遗传重新正常化 在 Ts65Dn 小鼠中显着挽救与海马 LTP 相关的转录发育不良 三体动物的认知缺陷。此外，外源 Brwd1 过表达——通过病毒介导 野生型动物中成年背侧海马神经元的转导 - 也会导致上下文缺陷 和空间记忆。我们假设 DS 大脑中的 BRWD1 三体性导致异常相互作用 BRWD1 和表观遗传景观之间的关系，从而促进全局基因表达 异常和认知缺陷。我们试图通过以下独立的但尚未验证的假设来检验这一假设： 协同目标：1）检查DS-like中Brwd1三体性与染色质功能障碍之间的关系 大脑，首要重点是 a) DS 样中组蛋白 PTM 表达的公正评估 使用与组蛋白 PTM 质量相结合的细胞分选方法对神经元和神经胶质细胞（+/- Brwd1 救援）进行分析 光谱测定法，b) 使用高度描绘 BRWD1 和改变的组蛋白 PTM 之间的直接相互作用 新颖的“设计者”基于核小体的测定和体内验证。 2）调查Brwd1的影响 DS 样脑中基因表达的三重倍增。我们的目标是进行公正的、全表观基因组的分析 Ts65Dn 大脑中 Brwd1 富集以及相关组蛋白 PTM，随后进行广泛比较 使用细胞类型特异性 RNA-seq 获得的基因表达谱。基于 CRISPR 的操作将 随后进行直接评估 Brwd1 靶基因对观察到的行为的贡献 异常。 3) 探索 Brwd1 三倍体对特定 SWI/SNF 染色质招募/活性的影响 使用生化和全基因组评估重塑 Ts65Dn 小鼠大脑中的复合物。这些 实验将使我们能够剖析染色质调节异常模式的功能后果 DS 大脑中的研究将有助于我们理解与大脑可塑性相关的神经表观遗传过程。