Enteroendocrine cells sense gut bacteria and activate a gut-brain pathway

项目总结 肠道中的微生物对大脑功能和行为有重大影响。 微生物-肠道-脑通讯的紊乱被认为参与了众所周知的 肠脑疾病，如肠易激综合征(IBS)和相关的功能性胃肠道疾病。然而，在那里 缺乏对肠道微生物的确切微生物机制和细胞途径的了解 与大脑进行交流。为了解决这一关键的知识差距，申请者率先开发了斑马鱼 用于研究微生物-肠道-脑通讯的系统。使用在体实时测量细胞活性 在斑马鱼中，申请人最近的研究表明，特定的肠道细菌直接激活专门的 肠上皮中的感觉细胞，即肠内分泌细胞(EECS)，通过受体瞬时受体 潜在的锚蛋白A1(TRPA1)。TRPA1+EECs的微生物、药理或光基因直接激活 激活肠神经，刺激迷走神经感觉神经节。初步研究确定了一个不同的子集 细菌衍生的色氨酸分解代谢物作为有效激活TRPA1的新型激动剂。该计划的目标是 拟议的研究是确定肠道细菌激活EEC的确切分子机制。 调节大脑活动的迷走神经感觉通路。中心假设是细菌分泌的色氨酸 分解代谢物通过一种新的EEC分泌信号刺激EECs中的TRPA1激活迷走感觉神经元 多肽，垂体腺苷环化酶激活多肽(PACAP)。为了测试这一点，申请者将首先使用 分子微生物学和斑马鱼生理学方法确定微生物途径和机制 这激活了EEC TRPA1信号。其次，申请者将使用体内迷走神经钙成像、光化学 和基因操作，以识别将肠道细菌信息传递到 迷走神经。最后，申请者将使用药物、基因和细胞移植方法来确定 一种将细菌信息从肠腔传递到迷走神经的EEC信号肽。建议数 预计研究将为我们理解分子机制做出重大的新贡献。 以及肠道细菌与大脑沟通的细胞途径。跨学科实验 该方法和全面的职业发展计划将把申请人的培训范围从 胃肠病学涉及迷走神经和脑生理学以及分子微生物学。一个多元化的团队 杜克大学和北卡罗来纳大学教堂山分校的资深研究人员，拥有从宿主微生物到微生物的各种专业知识 从肠脑生理学到细菌学的互动，将监督申请者在 授勋期间，她在智力上为她的研究培训做出贡献，提供指导，并提供职业 建议。这项为期5年的职业发展奖将为申请者提供必要的专业和 具备独立和成功的微生物群-肠道-脑科学家的科学技能。

PROJECT SUMMARY Microorganisms residing in the intestinal lumen have a significant impact on brain function and behavior. Perturbation of microbe-gut-brain communication is believed to be involved in the pathogenesis of well-known gut-brain disorders such as irritable bowel syndrome (IBS) and related functional GI disorders. However, there is lack of understanding of the precise microbial mechanisms and the cellular pathways that allow gut microbes to communicate with the brain. To address this critical knowledge gap, the applicant has pioneered the zebrafish system for the study of microbe-gut-brain communication. Using in vivo real-time measurements of cell activity in zebrafish, the applicant’s recent research revealed that specific gut bacteria directly activate specialized sensory cells in the intestine epithelium, enteroendocrine cells (EECs), through the receptor transient receptor potential ankyrin A1 (Trpa1). Microbial, pharmacological, or optogenetic activation of Trpa1+EECs directly activates enteric neurons and stimulates vagal sensory ganglia. Preliminary studies identified a distinct subset of bacterial derived tryptophan catabolites as novel agonists that potently activate Trpa1. The objective of the proposed research is to determine the precise molecular mechanism by which enteric bacteria activate the EEC- vagal sensory pathway to modulate brain activity. The central hypothesis is that bacterial secreted tryptophan catabolites stimulate Trpa1 in EECs to activate vagal sensory neurons through a novel EEC secreted signal peptide, pituitary adenylate cyclase activating polypeptide (Pacap). To test this, the applicant will first use molecular microbiology and zebrafish gnotobiotic approaches to define the microbial pathway and mechanism that activates EEC Trpa1 signaling. Second, the applicant will use in vivo vagal calcium imaging, optochemical and genetic manipulation to identify the specific subtype of EECs that transmit enteric bacterial information to the vagus. Finally, the applicant will use pharmaceutical, genetic and cell transplantation approaches to define the EEC signaling peptide that transmits bacterial information from the gut lumen to the vagus. The proposed research is expected to make a significant new contribution to our understanding of the molecular mechanisms and cellular pathways by which enteric bacteria communicate with the brain. The interdisciplinary experimental approach together with the comprehensive career development plan will extend the applicant’s training from gastroenterology into vagal and brain physiology as well as molecular microbiology. A diverse team of established investigators at Duke University and UNC Chapel Hill, with expertise ranging from host-microbe interaction to gut-brain physiology to bacteriology, will oversee the applicant’s career development during the award period by contributing intellectually to her research training, providing mentorship, and offering career advice. This 5-year career development award will provide the applicant with the necessary professional and scientific skills to be an independent and successful microbiota-gut-brain scientist.