Mechanisms controlling human microglia gene expression

摘要 小神经胶质细胞是存在于中枢神经系统（CNS）中的组织巨噬细胞，并且执行独特的功能， 对中枢神经系统发育、体内平衡、免疫和修复至关重要的关键辅助功能。这些角色，沿着 随着逐渐认识到小胶质细胞可以促进神经系统疾病的过程，提供了一个 这是一个令人信服的理由，以便更清楚地了解规范其发展和功能的机制。 主要的未解之谜包括确定大脑中触发大脑活动的信号组合。 红骨髓祖细胞（EMP）分化为成熟的小胶质细胞，以及这些细胞中的改变如何影响 信号指定健康和疾病中不同的小胶质细胞表型。在此支持下进行的研究 过去四年的赠款为解决这些问题奠定了基础。四个具体目标是 提出了具体目标1是定义表达和染色质定量性状基因座， 人类小胶质细胞中的转录因子。这些研究将为神经科学提供宝贵的资源 目标2、3和4中的社区和信息研究。具体目标2是定义介导的顺式调节元件， 小胶质细胞基因表达的脑环境依赖性调节，重点关注小胶质细胞特异性谱系 决定因子SALL 1。重要的是，我们的实验计划将利用最近的能力，以实现在体内 小鼠脑内的人类小胶质细胞表型作为环境功能分析的背景- 依赖性增强子。具体目标3是检验脑环境依赖性基因可以被激活的假设。 通过环境依赖性转录的条件表达在iPSC衍生的小胶质细胞中体外激活 因素这些因子在体外人iPSC衍生的小胶质细胞中的强制表达将为以下方面提供见解： 它们的分子功能，并可能使改进的体外小胶质细胞模型系统的开发成为可能。具体 目的4是进行体内ASO介导的功能丧失实验，以鉴定转录介质， 脑环境因素。这一目标是基于反义寡核苷酸（阿索）化学的进展， 现在使使用ASO显着改变小胶质细胞和其他细胞类型的基因表达成为可能。 大脑在体内。与此同时，拟议的研究旨在从质的方面促进对 建立人类小胶质细胞基因表达的脑环境依赖性程序的机制。

Abstract Microglia are tissue macrophages that reside in the central nervous system (CNS) and perform unique and critical auxiliary functions important to CNS development, homeostasis, immunity and repair. These roles, along with the progressive appreciation that microglia can contribute to neurological disease processes, provides a compelling case to more clearly understand the mechanisms that regulate their development and functions. Major unanswered questions include determining the combination of signals within the brain that trigger the differentiation of erythromyeloid progenitor (EMP) cells to become mature microglia and how alterations in these signals specify distinct microglia phenotypes in health and disease. Studies performed under the support of this grant for the past four years provide the foundations for addressing these questions. Four Specific Aims are proposed. Specific Aim 1 is to define expression and chromatin Quantitative Trait Loci and collaborative transcription factors in human microglia. These studies will generate a valuable resource for the neuroscience community and inform studies in Aims 2, 3 and 4. Specific Aim 2 is to define cis regulatory elements that mediate brain environment-dependent regulation of microglia gene expression, focusing on the microglia-specific lineage determining factor SALL1. Importantly, our experimental plan will exploit the recent ability to achieve an in vivo human microglia phenotype within the mouse brain as the context for analysis of the function of environment- dependent enhancers. Specific Aim 3 is to test the hypothesis that brain environment-dependent genes can be activated in iPSC-derived microglia in vitro by conditional expression of environment-dependent transcription factors. Forced expression of these factors in human iPSC-derived microglia in vitro will provide insights into their molecular functions and may enable development of improved in vitro microglia model systems. Specific Aim 4 is to perform in vivo ASO-mediated loss of function experiments to identify transcriptional mediators of brain environmental factors. This aim is based on advances in anti-sense oligonucleotide (ASO) chemistry that now make it possible to use ASOs to significantly alter gene expression in microglia and other cell types of the brain in vivo. In concert, the proposed studies are intended to qualitatively advance understanding of mechanisms that establish the brain environment dependent program of human microglia gene expression.