The impact of proliferating mast cells in the developing brain

项目摘要 常驻和外周免疫细胞越来越多地参与各种疾病的病理生理过程。 神经发育障碍，包括自闭症，但这些非神经细胞影响的机制 大脑在很大程度上是未知的。大脑中渗透的免疫细胞很容易对环境触发因素做出反应， 促进持续的促炎信号，永久改变发育中的细胞并损害非 更新人口。大脑的常驻免疫细胞，小胶质细胞，调节正常的生理过程。 以引导大脑发育，但对渗入的免疫细胞对这些细胞的作用知之甚少 流程。在我的初步研究中，我发现了数千个肥大细胞，这是先天免疫系统的一个组成部分， 在大脑发育的整个围产期，都居住在毗邻海马体的侧脑室。 这就提出了一个问题--这种促炎细胞在发育中的大脑中可能扮演什么角色？肥大细胞 (MC)既对各种刺激高度敏感，又反射性地产生多种血管活性物质 分子、细胞因子和生长因子，使它们成为神经发育过程中潜在的神经免疫中心。 此外，由于肥大细胞对炎症信号的反应非常灵敏，它们可能具有双重功能： 潜在地支持细胞的发生和成熟，或造成损害。这项提议旨在解决差距。 在我们对MC招募、异质性和发育中大脑的功能的理解中，来评估这是如何 人口可能导致神经发育障碍。我们第一次展示了大脑MC 沿着海马裂复制，并在出生后的头两周保持在这个区域， 在附近发生平行的神经发生和小胶质细胞成熟。先进的流式细胞仪技术将 测试它们在局部增殖的假设，MC通常不会在骨髓外进行这一假设 (目标1.1)。为了阐明它们在发育中的中枢神经系统中的功能和分子特性，我们将进行单细胞 脑MCs的RNA测序及其转录组与皮肤和骨中MCs的比较 骨髓(目标1.2)。转录分析的结果将指导探索它们的影响机制 关于海马体的典型发育过程。最后，众所周知，MC与小胶质细胞相互协调 在受伤的成人大脑中，但这种关系在发育过程中还没有得到彻底的探索。我们将测试 我们的假设是MC释放信号因子促进海马区小胶质细胞成熟(AIM 2)。这些发现将重新定义对大脑发育的理解，认为大脑是一个免疫激活的部位，需要 细微差别的神经免疫相互作用以维持发育过程。该项目促进了对 生物信息学和沉浸在两个历史上独立的领域，为我的职业调查做准备 健康和疾病中的神经免疫交流。神经科学家玛格丽特博士的科学指导 麦卡锡和免疫学家尼尔·辛格博士，神经免疫学家大卫博士的临床指导 贝纳维德斯，将为我作为一名儿童神经学领域的内科科学家的生活奠定坚实的基础。

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.