The impact of proliferating mast cells in the developing brain

项目摘要 常驻免疫细胞和外周免疫细胞两者越来越多地涉及各种免疫缺陷的病理生理学。 神经发育障碍，包括自闭症，但这些非神经元细胞的影响机制， 大脑在很大程度上是未知的。大脑中浸润的免疫细胞很容易对环境触发做出反应， 促进持续的促炎信号传导，永久性地改变发育中的细胞并损害非炎症细胞。 更新人口。小胶质细胞是大脑中的常驻免疫细胞，它调节正常的生理过程 引导大脑发育，但很少有人知道浸润免疫细胞对这些相同的贡献。 流程.在我的初步研究中，我发现了数千个肥大细胞，先天免疫系统的一个组成部分， 在大脑发育的整个围产期阶段，栖息在海马附近的侧脑室。 这就提出了一个问题--这种促炎细胞在发育中的大脑中起什么作用？肥大细胞 (MC)对各种刺激高度敏感，并反射性地产生各种各样的血管活性物质， 分子、细胞因子和生长因子，使其成为神经发育过程中潜在的神经免疫枢纽。 此外，由于肥大细胞对炎症信号的反应如此灵敏，它们可能具有双重功能： 潜在地支持细胞发生和成熟或造成损害。该提案旨在弥补差距 在我们对发育中的大脑中MC募集、异质性和功能的理解中， 可能导致神经发育障碍。我们首次证明，大脑MC 沿着海马裂沿着复制，并在出生后的前两周内保持在该区域， 与附近发生的神经发生和小胶质细胞成熟平行。先进的流式细胞技术将 检验它们是局部增殖的假设，而MC通常不在骨髓外增殖 (Aim 1.1）。为了阐明它们在发育中的CNS中的功能和分子特性，我们将进行单细胞 脑MC的RNA测序并将其转录组与来自皮肤和骨骼的原型MC进行比较 骨髓（目标1.2）。转录组学分析的结果将指导其影响机制的探索 海马体的典型发育过程。最后，众所周知，MC与小胶质细胞协调 在受伤的成年大脑中，这种关系在发育过程中尚未得到彻底的探索。我们将测试 我们的假设是MCs释放促进海马小胶质细胞成熟的信号因子（目的 2）。这些发现将重新理解发育中的大脑是一个免疫激活的部位， 微妙的神经免疫相互作用来维持发育过程。该项目促进以下方面的培训 生物信息学和沉浸在两个历史上独立的领域，为我的职业生涯做好准备， 健康和疾病中的神经免疫通讯。来自神经科学家玛格丽特博士的科学指导 麦卡锡和免疫学家内维尔·辛格博士，神经免疫学家大卫博士的临床指导 贝纳维德斯，将建立一个强大的基础，我的生活作为一个医生，科学家在儿童神经学领域。

Project Summary Both resident and peripheral immune cells are increasingly implicated in the pathophysiology of various neurodevelopmental disorders, including autism, but the mechanisms by which these non-neuronal cells impact the brain is largely unknown. Infiltrating immune cells in the brain readily respond to environmental triggers, promoting persistent proinflammatory signaling that permanently alters developing cells and damages non- renewing populations. The resident immune cells of the brain, microglia, regulate normal physiologic processes to guide brain development, but little is known about the contribution of infiltrating immune cells to these same processes. In my preliminary studies, I found thousands of mast cells, a component of the innate immune system, inhabiting the lateral ventricles adjacent the hippocampus, throughout perinatal stages of brain development. This raises the question – what role might such proinflammatory cells serve in the developing brain? Mast cells (MC) are both highly sensitive to a variety of stimuli and reflexively produce a wide assortment of vasoactive molecules, cytokines, and growth factors, making them a potential neuro-immune hub during neurodevelopment. Moreover, since mast cells are so exquisitely responsive to inflammatory signals, they may serve dual functions: potentially supporting cell genesis and maturation, or perpetrating damage. This proposal seeks to address gaps in our understanding of MC recruitment, heterogeneity, and function in the developing brain to assess how this population may contribute to neurodevelopmental disorders. We have shown, for the first time, that brain MC are replicating along the hippocampal fissure and are maintained in this region for the first two postnatal weeks, paralleling neurogenesis and microglial maturation occurring nearby. Advanced flow cytometric techniques will test the hypothesis that they are locally proliferating, which MC do not typically do outside of the bone marrow (Aim 1.1). To elucidate their functional and molecular identity in the developing CNS, we will perform single cell RNA-sequencing of brain MCs and compare their transcriptome to prototypical MCs from the skin and bone marrow (Aim 1.2). Findings from transcriptomic analyses will guide exploration of their mechanism of influence on typical developmental processes in the hippocampus. Lastly, MC are well known to coordinate with microglia in the injured adult brain, but this relationship has not been thoroughly explored during development. We will test our hypothesis that MCs release signaling factors that promote microglial maturation in the hippocampus (Aim 2). These findings will reframe understanding of the developing brain as an immune-enabled site requiring nuanced neuro-immune interactions to sustain developmental processes. This project fosters training in bioinformatics and immersion in two historically independent fields to prepare me for a career investigating neural-immune communication in health and disease. Scientific mentorship from neuroscientist Dr. Margaret McCarthy and immunologist Dr. Nevil Singh, paralleled by clinical mentorship from neuroimmunologist Dr. David Benavides, will establish a strong foundation for my life as a physician-scientist in the field of child neurology.