Gene regulatory networks influencing neuron-microglia interactions in fetal brain development.

项目摘要/摘要 产前是大脑发育的敏感和关键时期，以神经发生波为特征， 神经元迁移和神经网络的形成。在妊娠的第一和第二个三个月，小胶质细胞是 大脑的主要免疫细胞，并参与大脑发育所必需的各种过程， 包括分泌神经营养因子和吞噬凋亡的神经前体细胞。胎儿小胶质细胞 功能障碍可导致异常的皮质层叠，导致脑病理风险增加。我们有 确认了许多参与小胶质细胞到皮质和皮质到小胶质细胞信号转导的配体-受体对 预测对人类胎儿小胶质细胞功能和胎儿大脑发育有贡献。我们遵守和谐一致 这些配体-受体对在脑器官和诱导的多能干细胞中的表达 小胶质细胞和我们的人类胎儿数据。COS可以模拟人类早期大脑发育，但目前的模型缺乏 大脑的免疫部分。我们的数据表明，诱导的多能干细胞来源的小胶质细胞共同- 用Cos(OMGs)培养的人胎儿小胶质细胞具有明显的表型特征。因此，一个 系统分析小胶质细胞整合到Cos后的神经成熟是使用这一方法的第一步。 探索神经元-小胶质细胞相互作用建立的分子机制的模型系统 早期的大脑回路。这项建议旨在使用CoS和OMGs来评估大脑环境信号和 相应的转录因子有助于胎儿的小胶质细胞行为和小胶质细胞与神经元的相互作用 在胎儿发育的早期。在K99阶段完成的目标1中，我将测试以下假设 小胶质细胞转化为Cos可促进神经成熟。此外，我还将测试人体内环境平衡的扰动 小胶质细胞中的脑环境信号会导致小胶质细胞功能障碍和神经元亚群的改变。在……里面 目标2，我将在整个过程中确定人类和小鼠小胶质细胞行为的转录因子网络 发展、动态平衡和炎症性侮辱之后。目标2的目标是发现物种- 小胶质细胞对炎症反应的保守机制用于改进治疗靶向和小鼠 建模并发现潜在的人类特有的疾病风险因素。此外，我还将检验这一假设 小胶质细胞发育转录因子在炎性侮辱后重新连接，导致长期- 小胶质细胞行为的持久变化和大脑回路的中断。目标2的研究将于年内完成 独立阶段。我的长期目标是阐明神经元-小胶质细胞的表观遗传学机制。 作为一个独立的调查者，在健康和疾病方面进行沟通。我已经召集了一个不同的高度 熟练的导师，他们将确保我在神经发展和神经评估方面接受广泛的培训 电路。加州大学圣迭戈分校独特的科学环境将进一步加强我的培训 社区，面向尖端技术和分析的开发和使用 方法评估大脑中细胞的异质性和动态的细胞-细胞相互作用。

Project Summary/Abstract The prenatal period is a sensitive and critical time for brain development characterized by waves of neurogenesis, neuronal migration, and formation of neural networks. In the first and second trimester, microglia are the dominant immune cells of the brain and participate in a variety of processes essential to brain development, including secreting neurotropic factors and engulfing apoptotic neural progenitor cells. Fetal microglia dysfunction can lead to aberrant cortical lamination, resulting in an increased risk of brain pathology. We have identified numerous ligand-receptor pairs involved in microglia-to-cortex and cortex-to-microglia signaling predicted to contribute to human fetal microglia function and fetal brain development. We observe concordant expression of these ligand-receptors pairs in cerebral organoids (COs) and induced pluripotent stem cell-derived microglia with our human fetal data. COs can model early human brain development, but current models lack the immune component of the brain. Our data suggest that induced pluripotent stem cell-derived microglia co- cultured with COs (oMGs) capture significant phenotypic characteristics of human fetal microglia. Thus, a systematic analysis of neural maturation following integration of microglia into COs is the first step in using this model system to interrogate the molecular mechanisms underlying how neuron-microglia interactions establish early brain circuitry. This proposal aims to use COs and oMGs to assess how brain environment signals and corresponding transcription factors contribute to fetal microglia behavior and microglial interaction with neurons in early fetal development. In Aim 1, completed in the K99 phase, I will test the hypothesis that integration of microglia into COs results in enhanced neural maturation. Additionally, I will test how perturbation of homeostatic brain environment signaling in microglia results in microglia dysfunction and altered neuronal subpopulations. In Aim 2, I will identify transcription factor networks underlying human and mouse microglia behavior throughout development, at homeostasis and after an inflammatory insult. The goal for Aim 2 is to uncover species- conserved mechanisms in microglia responses to inflammation for improved therapeutic targeting and murine modeling and to discover potential human-specific risk factors for disease. Additionally, I will test the hypothesis that microglial developmental transcriptional factors are re-wired following an inflammatory insult, leading to long- lasting changes in microglia behavior and disruption of brain circuitry. Studies in Aim 2 will be completed in the independent phase. My long-term goal is to elucidate the epigenetic mechanisms underlying neuronal-microglia communication in health and disease as an independent investigator. I have assembled a diverse group of highly skilled mentors who will ensure that I receive extensive training in neurodevelopment and assessment of neural circuits. My training will be further enhanced by the unique scientific environment of the UCSD research community, which is geared towards the development and usage of cutting-edge technology and analytic methods to assess cellular heterogeneity and dynamic cell-cell interactions in the brain.