Defining the interactions between microglia and synapses in brain development and disease

项目总结/摘要 建立精确的突触连接对正常的大脑功能至关重要。突触功能障碍会导致 神经元过度兴奋，导致包括癫痫在内的疾病。小胶质细胞是主要的免疫细胞 在大脑中，并在突触发育、调节神经元兴奋性和吞噬中发挥多种作用 过度兴奋性突触然而，小胶质细胞影响突触的机制主要是 用固定的组织组织学或在成年人大脑的有限区域中使用啮齿动物模型进行研究。事实上， 在发育中的脑中没有直接观察到小胶质细胞吞噬整个突触。在这一提议中， 我将使用斑马鱼模型系统来研究完整发育中大脑中小胶质细胞-突触的相互作用。我 最近发表的一项研究发现，在斑马鱼中富集了一群突触相关小胶质细胞（SAM 并通过单细胞和区域批量测序确定其转录谱。在这份提案中，我将 使用活体成像和候选基因缺失的组合检查这一小胶质细胞亚群， 生理学和过度兴奋的背景下。AIM 1将确定小胶质细胞是否会在 发展和免疫激活的影响，或删除后的核心溶酶体蛋白酶称为 组织蛋白酶B（ctsba）-我的转录组学工作中的一个最佳候选者。目标2将进一步评估这些表型 在化学诱导的过度兴奋的背景下，并使用惊吓行为记录来评估影响 神经回路功能最后，在目标3（R 00阶段），我将定义调节的分子机制， 小胶质细胞吞噬过程中溶酶体活性和神经元刺激后小胶质细胞的转录谱 兴奋过度这些研究将共同开辟一个独特的方向，使用新的模型来识别分子 调节小胶质细胞-突触相互作用的途径，具有研究非神经元治疗的潜力 影响发育和疾病状态（如癫痫）的干预措施。

PROJECT SUMMARY/ ABSTRACT Establishing precise synaptic connections is critical for normal brain function. Synaptic dysfunction can lead to neuronal hyperexcitability, contributing to disorders including epilepsy. Microglia are the dominant immune cells in the brain and play multiple roles in synaptic development, modulating neuronal excitability, and engulfing excess excitatory synapses. However, the mechanisms by which microglia impact synapses have largely been investigated with fixed tissue histology or in limited regions of the adult brain using rodent models. In fact, microglial engulfment of whole synapses has not been directly observed in the developing brain. In this proposal, I will use a zebrafish model system to study microglial-synapse interactions in the intact developing brain. My recently published work identified a population of synapse-associated microglia (SAMs) enriched in the zebrafish hindbrain and defined its transcriptional profile by single-cell and regional bulk sequencing. In this proposal, I will examine this microglial subset using a combination of live imaging and candidate gene deletion in both physiology and in the context of hyperexcitability. Aim 1 will determine if microglia engulf synapses during development and the impact of immune activation or after deletion of a core lysosomal protease known as cathepsin b (ctsba) - a top candidate from my transcriptomic work. Aim 2 will further assess these phenotypes in the context of chemically induced hyperexcitability and use startle behavior recordings to assess the impact on neural circuit function. Finally, in Aim 3 (R00 phase), I will define the molecular mechanisms regulating lysosome activity during microglia phagocytosis and transcriptionally profile microglia following neuronal hyperexcitability. Together these studies will open a distinct direction using a new model to identify molecular pathways that regulate microglia-synaptic interactions with the potential to investigate non-neuronal therapeutic interventions that impact development and disease states such as epilepsy.