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.

项目概要 该项目将测试细菌胆盐水解酶 (BSH) 活性调节的假设 通过肠神经系统中的信号通路以剂量依赖性方式调节肠道蠕动 (ENS)，其中包括 RET，一种对 ENS 发育和功能至关重要的酪氨酸激酶受体， TGR5，唯一已知由肠神经元表达的胆汁酸受体。探索 在这个假设中，我将整合各种技术来产生功能读数，结合 饮食依赖性胆汁酸介导的运动表型的限生小鼠模型 光谱测定法、下一代测序和生物信息学。在目标 1 中，我建议确定 肠道蠕动受细菌 BSH 活性调节的程度。一、菌株 从单个健康孟加拉国人的微生物群中培养的将被归类为 使用已建立的体外筛选具有高、中或低 BSH 活性。这些 菌株已经过初步筛选以确定是否存在 BSH；在这里我 将用低至 3 小时的时间尺度分辨率来描述 BSH 活动的特征 小鼠体内两种主要的初级胆汁酸底物（牛磺胆酸和牛磺-β-鼠胆酸） 酸）。然后，选择具有高/中/低BSH活性的菌株将被移植到gnotobiotic中 小鼠以确定 (i) BSH 活性与肠道运动的相关程度，以及 (ii) 是否 BSH 的运动效应对分类多样性具有很强的鲁棒性（对于理解 研究结果的普遍性）。未来，我的目标是启动一项临床研究来测试 假设肠道细菌 BSH 活性与腹泻或腹泻患者的运动相关 以便秘为主的肠易激综合征，以确定其中的子集 细菌胆汁酸代谢可以作为治疗靶点。在目标 2 中，我建议确定 微生物组编码的 BSH 活性对肠道运动影响的关键 ENS 介质。到 确定 TGR5 胆汁酸受体是否负责介导这种胆汁酸- 依赖性反应，我将使用常规饲养的限生 Tgr5-/- 小鼠。识别 关键的ENS分子介质和通路，我将采用TRAP-Seq（翻译核糖体 亲和纯化测序），一种为研究不同群体的技术而开发的技术 小鼠大脑，以分析限生小鼠的 ENS。使用这种方法，我将阐明 胆动力剂（姜黄）的影响和模型人类肠道细菌群落 定义了小肠和结肠中 ENS 转录组的 BSH 活性，将 这些信号具有测量的传输时间和胆汁酸分布。综合起来，这些数据得到了 来自人源化无菌小鼠的研究将有助于剖析细菌胆汁酸的程度 新陈代谢调节肠道蠕动并提供有关相互作用的机制见解 膳食成分、肠道微生物组和调节 ENS 信号通路之间的关系 动力。后续的研究将涉及移植完整的未培养的微生物群 选择具有运动障碍的表型良好的人类转化为无菌小鼠。