BRD4-mediated regulation of human brain development and function

我的长期研究目标是研究大脑发育和功能的分子调控。我的研究项目应用了两种独特的技术：干细胞工程和计算分析，这是一种很有前途的方法，可以从个体中产生各种类型的细胞和组织，并处理来自干细胞衍生的细胞类型和组织的大规模生物数据。大脑是控制我们情绪和行为过程的最复杂和最重要的器官之一。大脑由多种类型的细胞组成，如神经元、星形胶质细胞和小胶质细胞，它们有自己独特的特性，并相互作用。每种细胞类型的分化是由独特的基因表达程序决定的。组蛋白是一种基本的蛋白质，它将DNA浓缩成一种紧密的形式，称为染色质。重要的是，已知组蛋白的化学修饰通过扰乱染色质结构来促进细胞类型特异性基因表达程序。尽管到目前为止已经报道了150多种组蛋白修饰酶，但它们在大脑发育中的大部分功能作用在很大程度上是未知的。BRD4是脑内大量表达并促进组蛋白赖氨酸残基乙酰化的修饰酶之一。我们之前发现BRD4的异常基因组结合会损害神经元生长和电激活。也有报道称BRD4还调节小胶质细胞分化和免疫应答。尽管这些数据表明BRD4对大脑神经元和神经胶质细胞的发育和功能至关重要，但BRD4如何调节多种细胞类型的细胞身份和不同特性仍不清楚。我们将利用完善的方案将人类胚胎干细胞分化为神经元、星形胶质细胞和小胶质细胞，并利用尖端的基因组学和蛋白质组学技术研究1)BRD4在不同细胞类型中的全基因组占据和2)蛋白-蛋白相互作用。此外，考虑到BRD4参与大脑细胞命运的决定，BRD4是否也有助于大脑细胞类型的结构组织是值得怀疑的。为了解决这个问题，我们将利用人胚胎干细胞三维培养系统培养微型大脑，并通过高分辨率成像分析分析BRD4是否影响大脑结构的组织。总体而言，该研究计划将采用体外组织建模和大规模数据集的计算机分析来阐明人类大脑发育的基本表观遗传调控。在整个计划项目中，学生将获得干细胞生物学，神经科学和生物信息学方面的广泛知识和专业知识。

My long-term research vision aims to study molecular regulations of brain development and functions. My research program applies two unique technologies: stem cell engineering and computational analysis that are promising approaches to generate various types of cells and tissues from individuals and handle large-scale biological data from the stem cell-derived cell types and tissues.  Brain is one of the most complex and important organs to control our emotional and behavioral processes. Brain is made up of multiple cell types, such as neurons, astrocytes, and microglia, that have their own unique properties and interact each other. Differentiation into each cell type is determined by the unique gene expression program. Histones are basic proteins that condense DNA into a compact form, called chromatin. Importantly, chemical modifications of histone proteins are known to contribute to the cell type-specific gene expression program by perturbing chromatin structure. Although more than 150 histone modifying enzymes have been reported so far, the most of their functional roles in brain development are largely unknown.  BRD4 is one of the modifying enzymes that are heavily expressed in brain and promote acetylation of lysine residues in histone proteins. We previously found that abnormal genomic binding of BRD4 impairs neuronal growth and electrical activation. It has been also reported that BRD4 also regulates glial cell differentiation and immune response of microglia. Although these data implicate that BRD4 is essential for development and function of both neuronal and glial cells in brain, it still remains unclear how BRD4 regulates cellular identity and distinct properties across multiple cell types.  We will differentiate human embryonic stem cells into neurons, astrocytes, and microglia with well-established protocols and investigate 1) genome-wide occupancy and 2) protein-protein interactions of BRD4 across different cell types using cutting-edge genomics and proteomics technologies. Furthermore, given the involvement of BRD4 in cell fate determination in brain, it is questionable 3) whether BRD4 also contributes structural organization of cell types in brain. To address this question, we will grow miniature brains from human embryonic stem cells with three-dimensional culture system and analyze whether BRD4 affects the organization of brain structure by high-resolution imaging analysis. Overall, the research program will employ in vitro tissue modeling and in silico analysis of large-scale datasets to shed light on fundamental epigenetic regulation of human brain development. Throughout the proposed project, students will obtain broad knowledge and expertise in stem cell biology, neuroscience, and bioinformatics.