The role of microbe-epithelial interactions on primate enteroneuroactivity in response to maternal high fat diet

神经化学信使，如5-羟色胺、多巴胺和伽马-氨基丁酸，几十年来一直与焦虑有关，但这些化合物主要是在肠道中产生的，既有肠道细胞，也有肠道微生物(也称为肠神经活动)。然而，肠道在儿童焦虑症的神经递质失调机制中的作用程度仍然知之甚少。这个项目的长期目标是调查微生物组-肠道-脑轴，它在童年时是如何形成的，以及它是如何促进早期生命神经发育的。本研究的总体目标是阐明微生物-上皮细胞相互作用对母体高脂饮食(MHFD)诱导的幼年非人灵长类动物(NHP)表现出焦虑样行为的肠道上皮细胞形态和功能的影响。暴露于mHFD的NHP青少年的初步数据显示，a)大脑中5-羟色胺和多巴胺的变化，b)mHFD-微生物处理的肠道上皮中5-羟色胺的减少，以及c)持续变化的肠道微生物群。中心假设是，持续的微生物-上皮相互作用是维持暴露于mHFD的NHP肠道中改变的肠神经活性功能所必需的。为了更好地理解体内相关数据，该项目的基本原理是通过培养来自对照和mHFD暴露的NHP的肠样和结肠样物质来产生体外机制数据。中心假说将通过追求两个特定的目标来检验，这两个目标将描述在没有和存在重新引入的肠道微生物的情况下，肠样/结肠样物质的细胞神经活性功能状态和组成形式。在第一个目标下，来自对照组和暴露于mHFD的NHP的肠样/结肠样细胞将在有和没有微生物的情况下进行培养，并比较肠神经活性化合物和酶水平(功能)。对于第二个目的，将比较肠神经活性细胞类型和受体(形式)的肠样/结肠样体。总而言之，这项分析将确定在体内观察到的肠神经活性特征是否在体外有或没有微生物复制。学员的环境通过贝勒医学院的肠样核心、德克萨斯州儿童微生物组中心的代谢组学实验室以及Aagaard实验室的长期NHP模型，为实现这些目标做好了完美的准备。本申请中提出的研究旨在加强学员的职业道路，使其在微生物学、胃肠病学和神经学领域成为充满活力的多学科专业，目标是成为一名学术儿科医生和科学家。这项拟议的研究具有重要意义，因为它有望确定在焦虑背景下，正在进行的微生物-宿主相互作用对肠神经活动形式和功能的必要性。归根结底，这些知识有可能确定儿童神经行为发育中的关键组成部分。

Neurochemical messengers like serotonin, dopamine, and gamma-aminobutyric acid have been linked to anxiety for decades, and yet these compounds are largely produced in the gut, both by intestinal cells and by gut microbes (aka enteroneuroactivity). However, the extent to which the gut contributes to the mechanism of neurotransmitter dysregulation in child anxiety remains poorly understood. The long-term goal of this project is to investigate the microbiome-gut-brain axis, how it is shaped in childhood, and how it contributes to early life neurodevelopment. The overall objective is to elucidate the effect of microbe-epithelial interactions on the form and function of gut epithelia in juvenile non-human primates (NHPs) that display anxiety-like behavior induced by maternal high fat diet (mHFD). Preliminary data in mHFD-exposed NHP juveniles demonstrate a) altered serotonin and dopamine in the brain, b) reduced serotonin in mHFD-microbe treated gut epithelia, and c) a persistently-altered gut microbiome. The central hypothesis is that ongoing microbe-epithelial interactions are required to perpetuate the altered enteroneuroactive function in the mHFD-exposed NHP gut. To better understand the in vivo associative data, the rationale for this project is to generate mechanistic data in vitro through the cultivation of enteroids and colonoids derived from control and mHFD-exposed NHPs. The central hypothesis will be tested by pursing two specific aims that will characterize the cellular enteroneuroactive functional status and compositional form of enteroids/colonoids in the absence and presence of reintroduced gut microbes. Under the first aim, enteroids/colonoids derived from control and mHFD-exposed NHPs will be cultured with and without microbes and compared for enteroneuroactive compound and enzyme levels (function). For the second aim, enteroids/colonoids will be compared for enteroneuroactive cell types and receptors (form). Together this analysis will determine if the enteroneuroactive profile witnessed in vivo is replicated in vitro with or without microbes. The trainee’s environment is perfectly primed to accomplish these aims via the enteroid core of Baylor College of Medicine, the metabolomics laboratory of the Texas Children’s Microbiome Center, and the longstanding NHP model of the Aagaard lab. The research proposed in this application is aimed to enhance the trainee’s career path towards a dynamic, multidisciplinary specialization in the fields of microbiology, gastroenterology, and neurology with the goal of becoming an academic pediatrician- scientist. The proposed research is significant because it is expected to determine the necessity of ongoing microbial-host interactions on the form and function of enteroneuroactivity in the context of anxiety. Ultimately, such knowledge has the potential to identify the critical components involved in childhood neurobehavioral development.