Investigating role of maternal gut microbiome in microglia-neuron dynamics and development of somatosensory circuits

项目摘要 感觉处理障碍与神经发育障碍有关，如自闭症谱系障碍 和智力残疾，每20名儿童中就有1名受到影响。越来越多的证据表明，产妇的环境 强烈影响神经发育障碍的病因，提示子宫因素，如 母体肠道微生物区系对胎儿大脑发育有着深远的影响。因此，理解这个角色 研究母体肠道微生物在神经回路和异常行为发育中的作用 神经发育障碍的潜在机制。最近的研究已经阐明了 发生在妊娠期间，母体肠道微生物区系的缺失会产生胎儿改变的后代 脑基因表达、胎儿丘脑皮质轴突发育减退和异常触觉感觉行为 在以后的生活中。这项提议旨在探索母体肠道微生物区系如何改变胎儿大脑发育。在目标1中 (K99)，母体肠道微生物组在产前小胶质细胞发育中的作用将通过以下方式确定 小胶质细胞基因表达的单细胞RNA测序、小胶质细胞形态和体内的清晰度成像 小胶质细胞功能的体感行为过程中清醒动物的成像。本建议书的目标2(K99) 将采用一种耗尽和新颖的无特定病原体(SPF)的胚胎小胶质细胞的“加回”方法 有正常肠道微生物区系的大脑，进入无菌母鸡后代的胚胎大脑 (GF)或抗生素治疗(ABX)，它们耗尽了母亲肠道微生物群。这套实验将 阐述小胶质细胞的因果作用，并测试小胶质细胞是否在母体肠道微生物群效应中起中介作用 关于大脑发育的研究。由于小胶质细胞的激活与自闭症谱系中的行为缺陷有关 精神障碍和精神分裂症，R00将利用K99阶段开发的技术来询问母亲 肠道微生物区系对小胶质细胞激活对胎儿大脑发育和晚年生活的影响 行为。这些目标的成功实现可能会带来新的治疗生物靶点。 干预，同时也扩大了我们对中枢神经发育过程中微生物的理解 系统。这些拟议的实验将为我提供新的方法学培训(单细胞RNA 测序和分析，以及清醒行为动物的体内成像)和概念(小胶质细胞生物学) 作为独立研究实验室的基础，该实验室将研究产妇肠道微生物和 神经免疫发育，并阐明细胞和分子机制 神经发育障碍。这项工作将在加州大学洛杉矶分校完成，在那里，技术和 智力的增长是数不清的。我将定期参加与导师和合作者的会议，以获得 对实验设计和职业建议的反馈。我将参加加州大学洛杉矶分校的拨款撰写和研究研讨会， 同时还通过在科学会议上发表演讲来提高我的沟通能力。共同努力，这份职业生涯 发展奖将帮助我建立并领导一个成功的神经发育生物学研究小组。

Project Summary Sensory processing disorder is associated with neurodevelopmental disorders such as autism spectrum disorder and intellectual disability, affecting 1 in 20 children. Increasing evidence reveal that the maternal environment strongly impacts the etiopathogenesis of neurodevelopmental disorders, suggesting in utero factors such as the maternal gut microbiota holds profound influence on fetal brain development. Therefore, understanding the role of maternal gut microbes in the development of neural circuits and abnormal behaviors can provide insights to the underlying mechanisms of neurodevelopmental disorders. Recent work has illuminated mechanisms that occur during gestation whereby the absence of the maternal gut microbiota yields offspring with altered fetal brain gene expression, reduced fetal thalamocortical axon development, and abnormal tactile sensory behavior in later life. This proposal aims to explore how maternal gut microbiota alters fetal brain development. In Aim 1 (K99), the role of the maternal gut microbiome in the development of prenatal microglia will be determined by single-cell RNA sequencing of microglia gene expression, CLARITY imaging of microglia morphology and in vivo imaging of awake animals during somatosensory behaviors for microglia function. Aim 2 of this proposal (K99) will employ a depletion and novel “add-back” approach of embryonic microglia from specific pathogen-free (SPF) brains, which have a normal gut microbiota, into embryonic brains of offspring from dams that are germ-free (GF) or antibiotic-treated (ABX), which are depleted of the maternal gut microbiome. This set of experiments will address the causal role of microglia and test whether prenatal microglia mediate maternal gut microbiome effects on brain development. Since microglial activation is implicated in behavioral deficits seen in autism spectrum disorder and schizophrenia, R00 will leverage techniques developed in the K99 phase to ask whether maternal gut microbiota contributes to the effects of microglial activation on fetal brain development and later life behaviors. The successful completion of these aims could lead to new biological targets for therapeutic intervention, while also expanding our understanding of microbes during development of the central nervous system. These proposed experiments will provide me with new training in methodologies (single cell RNA sequencing and analysis, and in vivo imaging of awake behaving animals) and concepts (microglial biology) to serve as the foundation of an independent research laboratory that will study maternal gut microbes and neuroimmune development, and elucidate the cellular and molecular mechanisms governing neurodevelopmental disorders. This work will be completed at UCLA, where the opportunities for technical and intellectual growth are innumerable. I will attend regular meetings with mentors and collaborators to receive feedback on experimental design and career advice. I will attend grant writing and research seminars at UCLA, while also improving my communication skills by presenting at scientific conferences. Together, this career development award will help me establish and lead a successful neurodevelopmental biology research group.