The gut microbiota, bile acid-mediated enteric nervous system signaling, and modulation of gastrointestinal motility

肠道微生物群、胆汁酸介导的肠神经系统信号传导以及胃肠道运动的调节

• 批准号: 9513086
• 负责人: Neelendu Dey
• 金额: $ 16.31万
• 依托单位: FRED HUTCHINSON CANCER RESEARCH CENTER
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-19 至 2021-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9513086
• 关键词: Adopted; Affect; Affinity Chromatography; Bangladeshi; Bile Acids; Bioinformatics; Brain; Cells; Clinical; Clinical Research; Colon; Communities; Complex; Constipation; Data; Diabetes Mellitus; Diarrhea; Diet; Digestion; Dose; Enteral; Enteric Nervous System; Food; Future; GPBAR1 gene; Gallbladder; Gastrointestinal Motility; Gastrointestinal tract structure; Genes; Genetic; Genetic Transcription; Germ-Free; Gnotobiotic; Hour; Human; Hydrolase; In Vitro; Individual; Inflammatory Bowel Diseases; Intestines; Irritable Bowel Syndrome; Mass Spectrum Analysis; Measures; Mediating; Mediator of activation protein; Metabolism; Methods; Microbe; Modeling; Molecular; Mus; Neurons; Pathway interactions; Patients; Phenotype; Physiological; Population; Preparation; Publishing; Receptor Protein-Tyrosine Kinases; Resolution; Ribosomes; Role; Signal Pathway; Signal Transduction; Signaling Molecule; Small Intestines; South Asian; Spices; Systems Development; Taurocholic Acid; Taxonomy; Technology; Testing; Time; Translating; Transplantation; Tumeric; Wild Type Mouse; bile salts; cell motility; follow-up; gut microbiome; high throughput screening; in vivo; insight; microbial; microbiome; microbiota; motility disorder; mouse model; muricholic acid; next generation sequencing; nutrient absorption; receptor; response; screening; targeted treatment; therapeutic target; transcriptome

PROJECT SUMMARY This project will test the hypothesis that bacterial bile salt hydrolase (BSH) activity regulates gut motility in a dose-dependent manner via signaling pathways in the enteric nervous system (ENS) that include RET, a tyrosine kinase receptor critical for ENS development and function, and TGR5, the only bile acid receptor known to be expressed by enteric neurons. To explore this hypothesis, I will integrate various technologies to produce functional readouts, combining a gnotobiotic mouse model of diet-dependent bile acid-mediated motility phenotypes with mass spectrometry, next-generation sequencing, and bioinformatics. In Aim 1, I propose to determine the extent to which gut motility is regulated by bacterial BSH activity. First, bacterial strains cultured from the microbiota of a single healthy Bangladeshi individual will be classified as possessing high, mid-level, or low BSH activity using an established in vitro screen. These strains have undergone preliminary screening to establish presence or absence of BSH; here I will characterize BSH activity with time-scale resolution down to 3 hours and with respect to the two predominant primary bile acid substrates in mice (taurocholic acid and tauro-beta-muricholic acid). Then, selected strains with high/mid/low BSH activity will be transplanted into gnotobiotic mice to determine (i) the extent to which BSH activity correlates with gut motility and (ii) whether BSH's motility effects are robust to taxonomic diversity (essential for understanding generalizability of the findings). In the future, I aim to initiate a clinical study to test the hypothesis that gut bacterial BSH activity correlates with motility in patients with diarrhea- or constipation-predominant irritable bowel syndrome, in order to identify subsets in whom bacterial bile acid metabolism could serve as a therapeutic target. In Aim 2, I propose to identify key ENS mediators of the effects of microbiome-encoded BSH activity on gut motility. To determine whether the TGR5 bile acid receptor is responsible for mediating this bile acid- dependent response, I will use conventionally raised and gnotobiotic Tgr5-/- mice. To identify key ENS molecular mediators and pathways, I will adopt TRAP-Seq (translating ribosome affinity purification sequencing), a technology developed to study distinct populations of the mouse brain, to profile the ENS in gnotobiotic mice. Using this approach, I will elucidate the effects of a cholekinetic agent (turmeric) and model human gut bacterial communities with defined BSH activity on the ENS transcriptome in the small intestine and colon, correlating these signals with measured transit times and bile acid profiles. Together, these data obtained from humanized gnotobiotic mice will help dissect the extent to which bacterial bile acid metabolism regulates gut motility and provide mechanistic insights regarding interactions between dietary ingredients, the gut microbiome, and ENS signaling pathways that regulate motility. Follow-up future studies will involve transplanting intact uncultured microbiota from selected well-phenotyped humans with motility disorders into gnotobiotic mice.

项目摘要 该项目将测试细菌胆汁盐水解酶（BSH）活性调节的假设 肠道运动通过肠神经系统中的信号通路以剂量依赖的方式运动 （ENS），包括RET，酪氨酸激酶受体至关重要的ENS发育和功能， 和TGR5，这是唯一被肠神经元表达的胆汁酸受体。探索 这个假设，我将整合各种技术以生成功能读数，结合了 饮食依赖性胆汁酸介导的运动型表型的gnotobiotic小鼠模型 光谱，下一代测序和生物信息学。在AIM 1中，我建议确定 细菌BSH活性调节肠道运动的程度。首先，细菌菌株 由单个健康孟加拉国人的微生物群培养的人将被归类为 使用已建立的体外筛查具有高，中级或低BSH活性。这些 菌株进行了初步筛查，以建立或不存在BSH。我在这里 将以时间尺度分辨率降至3小时的时间尺度表征BSH活动，相对于 小鼠中的两个主要的原发性胆汁酸底物 酸）。然后，将选定的具有高/中/低BSH活性的菌株移植到Gnotobiotic中 小鼠确定（i）BSH活性与肠运动性相关的程度以及（ii）是否存在 BSH的运动效应对分类学多样性是强大的（对于理解至关重要 调查结果的普遍性）。将来，我旨在启动一项临床研究以测试 假设肠胃腹泻或 便秘促炎肠综合症，以识别子集 细菌胆汁酸代谢可以用作治疗靶点。在AIM 2中，我建议确定 微生物组编码的BSH活性对肠道运动的影响的关键介体。到 确定TGR5胆汁酸受体是否负责介导这种胆汁酸 依赖性响应，我将使用常规饲养和gnotobiotic TGR5 - / - 小鼠。识别 关键ENS分子介质和途径，我将采用陷阱序列（翻译核糖体 亲和力纯化测序），一种用于研究不同种群的技术 小鼠大脑，介绍gnotobiotic小鼠中的ENS。使用这种方法，我将阐明 cholekoinetic剂（姜黄）和与人类肠道细菌群落建模的影响 在小肠和结肠中的ENS转录组上定义的BSH活动，相关 这些信号具有测量的运输时间和胆汁酸轮廓。这些数据共同获得 来自人源化的gnotobiotic小鼠将有助于剖析细菌胆汁酸的程度 代谢调节肠道运动，并提供有关相互作用的机械见解 在饮食成分，肠道微生物组和ENS信号传导途径之间 运动。后续研究将涉及从中移植完整的未养殖微生物群 选定的具有运动障碍的良好表现为gnotobiotic小鼠。