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: 10545761
• 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 2023-07-19
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10545761
• 关键词: Adhesions; Adhesives; Bacteria; Bacterial Adhesion; Bacteroides; Bar Codes; Binding; Biological Assay; Carbohydrates; Carbon; Cell Adhesion; Cells; Collection; Communities; Consumption; Databases; Diarrhea; Diet; Dietary Carbohydrates; Dietary Component; Dietary Fiber; Dietary Intervention; Disease; Enzymes; Epithelium; 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; 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.

项目摘要 居住在人类肠道中的微生物群落深远影响宿主新陈代谢，免疫 稳态和肠感染的结果。饮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。不过，目前很难 预测哪些肠道细菌将对基于纤维的饮食干预，种间竞争做出反应 可以使用特定的纤维类型准确地靶向有益的有益物种。细菌物种 具有致病潜力，例如肝癌大肠杆菌（UPEC），存在于肠道菌群中 无症状的个体和这些物种具有响应纤维的扩展能力。利用 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的基因， 包括介导对富含营养的饮食衍生颗粒的基因。以下目标将测试 假设（i）响应饮食纤维的肠道中共生大肠杆菌的扩展可以降低适应性 致病性大肠杆菌，以及（ii）共生和致病细菌种类竞争遵守 肠腔中相同的饮食衍生表面。在AIM1中，我将确定有选择地增加的饮食纤维 体内共生大肠杆菌的抽象。初步研究已经确定了一种广泛消耗的纤维 在模型微生物群落中增加了共生大肠杆菌的抽象。我将定义的机制 通过用大肠杆菌转座子突变图库殖民这些小鼠的行动并在社区范围内进行 定量蛋白质组学和正向遗传分析。为了建模致病大肠杆菌的肠道储层，我将 在这个社区中代替UPEC代替共生大肠杆菌，然后用OR或 没有纤维来识别减少UPEC抽象的干预措施。在AIM2中，我将确定是否 共生和致病性微生物粘附在肠道中的相同表面。多重粘合剂测定， 使用涂有聚糖的磁珠，确定了支持UPEC和UPEC粘合剂的饮食纤维 共生大肠杆菌。我将通过将这些颗粒施用到小鼠和 测量原位珠子周围的细菌定位。将基于珠的粘附测定应用于Cecal 用未培养的人类粪便样品殖民的小鼠的菌群也将确定其他大肠杆菌菌株 作为未表征的肠道微生物，它坚持体内饮食中的聚糖。这项研究将（i）提供见解 进入确定旨在促进的饮食干预措施的结果的生态关系 有益物种以已知病原体为代价，而II）提供候选饮食成分，细菌 菌株和微生物遗传靶标，用于操纵这些关系以增强人类健康。