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

神经化学信使，如血清素、多巴胺和γ -氨基丁酸，几十年来一直被认为与焦虑有关，然而这些化合物主要是在肠道中由肠道细胞和肠道微生物（又名肠神经活性）产生的。然而，肠道对儿童焦虑中神经递质失调机制的影响程度仍然知之甚少。该项目的长期目标是研究微生物群-肠-脑轴，它在儿童时期是如何形成的，以及它如何促进早期生命神经发育。总体目标是阐明微生物-上皮相互作用对幼年非人灵长类动物（NHPs）肠道上皮形态和功能的影响，这些动物表现出由母体高脂肪饮食（mHFD）诱导的焦虑样行为。暴露于mhfd的NHP幼崽的初步数据表明：a)大脑中的5 -羟色胺和多巴胺改变，b) mhfd微生物处理的肠道上皮中5 -羟色胺减少，c)肠道微生物组持续改变。核心假设是，在mhfd暴露的NHP肠道中，需要持续的微生物-上皮相互作用来维持改变的肠神经活性功能。为了更好地了解体内相关数据，本项目的基本原理是通过培养来自对照和暴露于mhfd的NHPs的肠样和结肠体，在体外产生机制数据。中心假设将通过追求两个特定目标来验证，这两个目标将表征在没有和存在重新引入的肠道微生物的情况下肠样/结肠体的细胞肠神经活性功能状态和组成形式。在第一个目标下，来自对照和mhfd暴露的NHPs的肠样/结肠体将在有微生物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）。对于第二个目标，将比较肠样细胞/结肠体的肠神经活性细胞类型和受体（形式）。总之，这一分析将确定体内观察到的肠神经活性谱是否在体外有或没有微生物的情况下被复制。通过贝勒医学院的肠道核心、德克萨斯儿童微生物组中心的代谢组学实验室和Aagaard实验室的长期NHP模型，学员的环境完全准备好了实现这些目标。本申请中提出的研究旨在加强实习生的职业道路，使其在微生物学、胃肠病学和神经病学领域成为一个充满活力的多学科专业，目标是成为一名学术儿科医生-科学家。拟议的研究是重要的，因为它有望确定正在进行的微生物-宿主相互作用对焦虑背景下肠神经活性的形式和功能的必要性。最终，这些知识有可能确定儿童神经行为发展的关键组成部分。

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.