Metabolic And Spatial Competition For Dietary Fiber Between Commensal And Pathogenic Gut Microbes

共生肠道微生物和致病肠道微生物之间膳食纤维的代谢和空间竞争

• 批准号: 10132316
• 负责人: Michael L Patnode
• 金额: $ 16.22万
• 依托单位: UNIVERSITY OF CALIFORNIA SANTA CRUZ
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-04-01 至 2024-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10132316
• 关键词: Adhesions; Adhesives; Bacteria; Bacterial Adhesion; Bacteroides; Bar Codes; Binding; Biological Assay; Carbohydrates; Carbon; Cecum; Cell Adhesion; Cells; Collection; Communities; Consumption; Databases; Diarrhea; Diet; Dietary Carbohydrates; Dietary Component; Dietary Fiber; Dietary Intervention; Disease; Enteral; Epithelial; Escherichia coli; Fiber; Food; Genes; Gnotobiotic; Goals; Growth; Harvest; Health; Homeostasis; Human; Immune; In Situ; Incubated; Individual; Infection; Intervention; Intestines; Knock-out; Knowledge; Lactobacillus; Libraries; Measures; Mediating; Metabolic; Metabolism; Microbe; Microbial Genetics; Modeling; Mus; Nitrogen; Nutrient; Organism; Outcome; Pathogenicity; Plants; Polysaccharides; Preparation; Probiotics; Proteobacteria; Proteomics; Psyllium; Research; Resources; Sampling; Surface; Testing; Urinary tract infection; Uropathogenic E. coli; Work; base; beneficial microorganism; commensal microbes; design; dietary; enteric infection; experimental study; fitness; genetic analysis; gut colonization; gut microbes; gut microbiota; in vivo; insight; interest; magnetic beads; member; microbial community; microbiota; mutant; particle; pathogen; pathogenic Escherichia coli; pathogenic microbe; prebiotics; response; therapy design; tool

PROJECT SUMMARY The microbial community that resides in the human intestine profoundly influences host metabolism, immune homeostasis, and the outcome of enteric infections. Dietary fiber is a promising tool for manipulating the gut microbiota to promote organisms that provide beneficial functions to the host. Though, it is currently difficult to predict which gut bacterial species will respond to fiber-based dietary interventions, interspecies competition makes it possible to precisely target beneficial species of interest using a particular fiber type. Bacterial species with pathogenic potential, such as uropathogenic E. coli (UPEC), are present in the gut microbiota of asymptomatic individuals and these species have the capacity to expand in response to fiber. Exploiting competition between pathogens and their non-pathogenic relatives to reduce pathogen load in the gut will require detailed knowledge of the genes underlying these species’ overlapping nutrient harvesting strategies, including genes mediating adhesion to nutrient-rich diet-derived particles. The following aims will test the hypotheses that (i) expansion of commensal E. coli in the gut in response to dietary fiber can reduce the fitness of pathogenic E. coli, and that (ii) commensal and pathogenic bacterial species compete for adhesion to the same diet-derived surfaces in the intestinal lumen. In Aim1, I will identify dietary fibers that selectively increase the abundance of commensal E. coli in vivo. Preliminary studies have identified a widely consumed fiber that increases the abundance of commensal E. coli in a model microbial community. I will define the mechanism of action by colonizing these mice with an E. coli transposon mutant library and performing community-wide quantitative proteomics and forward genetic analyses. To model a gut reservoir of pathogenic E. coli, I will substitute UPEC for commensal E. coli in this community, and then administer commensal E. coli with or without fiber to identify interventions that reduce UPEC abundance. In Aim2, I will determine whether commensal and pathogenic microbes adhere to the same surfaces in the gut. A multiplex adhesion assay, using glycan-coated magnetic beads, identified dietary fibers that support adhesion of both UPEC and commensal E. coli. I will validate adhesive interactions in vivo by administering these particles to mice and measuring bacterial localization around beads in situ. Application of the bead-based adhesion assay to cecal microbiota of mice colonized with uncultured human fecal samples will identify additional E. coli strains, as well as uncharacterized gut microbes, that adhere to dietary glycans in vivo. This research will (i) provide insights into the ecological relationships that determine the outcome of dietary interventions designed to promote beneficial species at the expense of known pathogens and ii) provide candidate dietary components, bacterial strains, and microbial genetic targets for manipulating these relationships to enhance human health.

项目概要 人类肠道内的微生物群落深刻影响宿主的新陈代谢、免疫功能 体内平衡和肠道感染的结果。膳食纤维是操纵肠道的有前途的工具 微生物群促进为宿主提供有益功能的生物体。虽然目前还很难 预测哪些肠道细菌会对基于纤维的饮食干预、种间竞争做出反应 使得使用特定纤维类型精确定位感兴趣的有益物种成为可能。细菌种类 具有致病潜力的细菌，例如尿路致病性大肠杆菌 (UPEC)，存在于以下人群的肠道微生物群中： 无症状个体和这些物种具有响应纤维而扩张的能力。剥削 病原体与其非致病亲属之间为减少肠道内病原体负荷而进行的竞争将 需要详细了解这些物种重叠的养分收获策略背后的基因， 包括介导对营养丰富的饮食颗粒的粘附的基因。以下目标将测试 假设 (i) 肠道内共生大肠杆菌对膳食纤维的反应会扩张，从而降低健康水平 致病性大肠杆菌，并且 (ii) 共生菌和致病菌物种竞争粘附到 肠腔中具有相同的饮食来源表面。在目标 1 中，我将确定选择性增加的膳食纤维 体内共生大肠杆菌的丰度。初步研究发现一种广泛食用的纤维 增加模型微生物群落中共生大肠杆菌的丰度。我将定义机制 通过用大肠杆菌转座子突变体库定植这些小鼠并在社区范围内进行 定量蛋白质组学和正向遗传分析。为了模拟致病性大肠杆菌的肠道储存库，我将 用 UPEC 替代该群落中的共生大肠杆菌，然后使用或施用共生大肠杆菌 没有纤维来确定减少 UPEC 丰度的干预措施。在 Aim2 中，我将确定是否 共生微生物和病原微生物粘附在肠道的相同表面。多重粘附测定， 使用聚糖涂层磁珠，确定了支持 UPEC 和 共生大肠杆菌。我将通过给小鼠施用这些颗粒来验证体内粘附相互作用 原位测量珠子周围的细菌定位。基于珠的粘附测定在盲肠中的应用 被未培养的人类粪便样本定植的小鼠的微生物群也将识别出其他大肠杆菌菌株 作为未表征的肠道微生物，它们在体内粘附于膳食聚糖上。这项研究将 (i) 提供见解 进入决定膳食干预结果的生态关系，旨在促进 ii) 提供候选膳食成分、细菌 菌株和微生物遗传目标来操纵这些关系以增强人类健康。