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.

项目摘要：迷宫我 呢 唐氏综合症（DS）是全世界最常见的智障遗传原因 人类染色体21（HSA21）的一式三重。尽管在理解遗传学方面取得了很多进展 DS，在HSA21上编码的基因，以及直接导致智力残疾及其的基因 相关的分子机制，仍然不完全理解。 BRWD1是一个未表征的大脑 在HSA21上的DS临界区域2中编码的富集染色质“读取器”蛋白。据信BRWD1 通过其提出的与SWI/SNF染色质重塑复合物的相互作用充当转录激活剂； 但是，它在神经发育和DS中的角色尚未研究。与 以前的基因表达分析在人DS脑中，我们观察到BRWD1表达显着 在trisomic小鼠以及来自DS受试者hipsC的神经元中升高。选择组蛋白 翻译后修改（PTM），我们已经证明其中一些与BRWD1直接相互作用， 他们的表达也有所改变。我们已经证明了BRWD1表达的遗传重新归一化 在TS65DN小鼠中，与海马LTP和 三方动物的认知缺陷。此外，外源BRWD1过表达 - 病毒介导 在野生型动物中转导成年背部神经元 - 也导致在这两个上下文中定义 和空间内存。我们的假设是，DS脑中的BRWD1三体性导致异常相互作用 在BRWD1和表观遗传景观之间，从而有助于全球基因表达 异常和认知缺陷。我们试图通过以下独立来检验这一假设 协同目的：1）检查DS样中的BRWD1三体和染色质功能障碍之间的关系 大脑，总体上强调a）对DS样中组蛋白PTM表达的无偏评估 神经元和神经元（+/– BRWD1救援）使用与组蛋白PTM质量耦合的细胞分选方法 光谱法和b）使用高度使用BRWD1和更改Hisstone PTM之间的直接相互作用的描述 新颖的“设计师”基于核小体的测定和体内验证。 2）研究BRWD1的影响 DS样脑中基因表达的一式陈述。我们的目标是对宽依性基因组进行无偏见的分析 BRWD1富集与相关组蛋白PTMS - 在TS65DN脑中，然后进行广泛的比较 使用细胞类型特异性RNA-seq获得的基因表达谱。基于CRISPR的操作会 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BRWD1三次固定对特定SWI/SNF染色质募集/活动的影响 使用生化和全基因组评估，在TS65DN小鼠脑中重塑复合物。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 在DS大脑中，将有助于我们理解与大脑可塑性相关的神经毛状过程。