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: 10327331
• 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/10327331
• 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.

项目总结 人体肠道中的微生物群落深刻地影响着宿主的新陈代谢、免疫 动态平衡和肠道感染的结果。膳食纤维是一种很有前途的肠道操作工具 微生物区系促进为寄主提供有益功能的生物体。不过，目前很难做到 预测哪些肠道细菌物种将对以纤维为基础的饮食干预、物种间竞争 使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，如尿路致病性大肠杆菌(UPEC)，存在于猪的肠道微生物区系中 没有症状的个体和这些物种有能力对纤维做出反应而扩张。剥削 病原体与其非致病亲属之间的竞争以减少肠道中的病原体负荷 需要详细了解这些物种重叠的营养收获策略背后的基因， 包括调节与营养丰富的饮食衍生颗粒的黏附的基因。以下目标将考验 假设(I)肠道中的共生大肠杆菌对膳食纤维的反应会降低适应性 致病性大肠杆菌，以及(Ii)共生和致病细菌物种竞争与 肠腔中同样的饮食衍生表面。在Aim1中，我将识别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，一种被广泛消费的纤维 增加模型微生物群落中共生大肠杆菌的丰度。我将会定义这个机制 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蓄水池，我将 用UPEC代替这个群落中的共生大肠杆菌，然后用或 没有纤维来确定降低UPEC丰度的干预措施。在AIM2中，我将确定是否 共生微生物和致病微生物附着在肠道的相同表面上。一种多重黏附试验， 使用葡聚糖包覆的磁珠，鉴定出支持UPEC和UPEC粘附性的膳食纤维 共生性大肠杆菌。我将通过给小鼠注射这些颗粒来验证体内的粘连相互作用 原位测量珠子周围的细菌定位。微球粘附法在盲肠粘附法中的应用 用未经培养的人类粪便样本定植的小鼠的微生物区系也将鉴定出更多的大肠杆菌菌株。 作为未知的肠道微生物，它们在体内附着在饮食中的多糖上。这项研究将(I)提供见解 生态关系决定了饮食干预的结果，旨在促进 以牺牲已知病原体为代价的有益物种和ii)提供候选饮食成分、细菌 菌株和微生物基因靶标，用于操纵这些关系以增进人类健康。