Microbial-derived purines in intestinal homeostasis

微生物来源的嘌呤在肠道稳态中的作用

• 批准号: 10415604
• 负责人: Joseph Scott Lee
• 金额: $ 0.69万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-06-01 至 2021-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10415604
• 关键词: Antigens; Apoptosis Regulation Gene; Bacteria; Bacterial Translocation; Basic Science; Biochemical; Caco-2 Cells; Cell Line; Cell physiology; Cells; Chronic; Clinical; Colitis; Colon; Disease; Environment; Epithelial Cells; Feedback; Fostering; Foundations; Gastrointestinal tract structure; Germ-Free; Glycolysis; Goblet Cells; Health; Homeostasis; Hypoxanthines; Hypoxia; Immune response; Immune system; Immunization; Inflammation; Inflammatory; Inflammatory Bowel Diseases; Injury; Intestinal Mucosa; Intestines; Knockout Mice; Liquid substance; Luciferases; Maintenance; Mediating; Mentorship; Metabolic; Metabolism; Microarray Analysis; Microbe; Modeling; Molecular; Mucins; Mucositis; Mucous Membrane; Mus; Nucleotides; Nutrient; Pathogenesis; Pathogenicity; Patients; Permeability; Physiological; Production; Publishing; Purines; Recovery; Regulation; Relapse; Reporter; Research; Resolution; Resources; Role; Science; Sodium Dextran Sulfate; Source; Stress; TP53 gene; Testing; Therapeutic; Tissues; Training; Work; base; care costs; dextran sulfate sodium induced colitis; dysbiosis; experience; gut microbiota; host microbiota; improved; inflammatory disease of the intestine; insight; interest; intestinal barrier; intestinal epithelium; intestinal homeostasis; knock-down; life time cost; microbial; microbiota; microorganism; novel; programs; promoter; purine metabolism; repaired; response; skills; small hairpin RNA; small molecule; tissue repair; transcription factor; trefoil factor; wasting; wound healing

PROJECT SUMMARY/ABSTRACT In a healthy gastrointestinal (GI) tract, intestinal epithelial cells (IECs) form a dynamic physical and biochemical barrier that maintains homeostasis by isolating the host immune system from an external environment of pathogenic and commensal microorganisms. Disruption of this barrier increases bacterial translocation, triggering inappropriate immune responses and unresolving inflammation. Dysregulation of IEC barrier in inflammatory bowel disease (IBD) and dysbiosis of the intestinal microbiota coincides with profound shifts in metabolic energy stores, especially in the colon, which exists in an energetically-vulnerable state of physiologic hypoxia. Substantial interest lies in understanding immunometabolism as a window to the molecular mechanisms of inflammatory progression or resolution, such as how metabolically active microbiota-derived small molecules promote intestinal homeostasis. Our ongoing work has identified purines as significant products of the intestinal microbiota. We identified a strong capacity for IECs to salvage hypoxanthine (Hpx) for ATP production, coinciding with improved barrier and wound healing capabilities. Furthermore, an unbiased microarray analysis of Hpx-treated T84 IECs identified TP53-inducible glycolysis and apoptosis regulator (TIGAR) as an induced target. We postulate that TIGAR induction by Hpx is central to mediating metabolism in response to purine availability or need for salvage due to stress-induced energetic deficits. In ongoing studies, we found that germ-free (GF) mice monocolonized with purine-producing bacteria have significantly increased colon tissue Hpx, with concomitant TIGAR induction. Further studies showed that the monocolonized mice were protected from dextran sulfate sodium (DSS)-induced colitis. Based on these results, we hypothesize that microbial-derived purines significantly contribute to intestinal homeostasis through TIGAR-mediated metabolic shifts. Aim 1 will define the mechanism(s) of Hpx-dependent TIGAR induction and the impact of that induction on purine metabolism. Aim 2 will elucidate the contribution of microbial-derived purines to intestinal homeostasis. Aim 3 will utilize TIGAR knockout (-/-) mice to assess the baseline contribution of TIGAR to intestinal homeostasis and inflammation resolution. This work lays a foundation for an IBD therapeutic in which patients are treated with nonpathogenic microbes specifically modified to produce small molecules (e.g. purines) that drive wound healing and inflammatory resolution. This proposal will provide outstanding mentorship and training under the guidance of an experienced sponsor in the ideal environment of a rigorous basic science lab that is well-integrated clinically, while having the necessary resources and mentorship to complete each aspect of this project, including a mentorship team within the Mucosal Inflammation Program. This training will foster the applicant’s independent science research skills in cross-cutting work that advances therapeutics for tissue damage repair and novel disease target identification.

项目概要/摘要 在健康的胃肠道 (GI) 中，肠上皮细胞 (IEC) 形成动态的物理和 通过将宿主免疫系统与外部环境隔离来维持体内平衡的生化屏障 病原微生物和共生微生物的环境被破坏，细菌就会增加。 易位，引发不适当的免疫反应和无法解决的 IEC 失调。 炎症性肠病（IBD）和肠道菌群失调的屏障与深刻的相一致 代谢能量储存的变化，尤其是在结肠中，其处于能量脆弱状态 生理性缺氧的重要意义在于将免疫代谢理解为分子生物学的窗口。 炎症进展或消退的机制，例如代谢活跃的微生物群如何产生 我们正在进行的工作已确定嘌呤是重要的产品。 我们发现 IEC 具有将次黄嘌呤 (Hpx) 转化为 ATP 的强大能力。 生产，同时还提高了屏障和伤口愈合能力。 对 HPX 处理的 T84 IEC 进行微阵列分析，鉴定出 TP53 诱导的糖酵解和凋亡调节因子 (TIGAR) 作为诱导靶标，我们假设 Hpx 诱导的 TIGAR 对于介导代谢至关重要。 在正在进行的研究中，对嘌呤可用性或由于压力引起的能量不足而需要挽救的反应。 我们发现，单定植有产生嘌呤的细菌的无菌（GF）小鼠的数量显着增加 结肠组织 Hpx，同时进行 TIGAR 诱导，进一步研究表明，单克隆小鼠是 根据这些结果，我们得出结论： 微生物来源的嘌呤通过 TIGAR 介导的代谢显着促进肠道稳态 目标 1 将定义 Hpx 依赖性 TIGAR 诱导的机制以及该诱导的影响。 目标 2 将阐明微生物来源的嘌呤对肠道稳态的贡献。 目标 3 将利用 TIGAR 敲除 (-/-) 小鼠来评估 TIGAR 对肠道的基线贡献 这项工作为 IBD 治疗奠定了基础。 经过专门修饰的非病原性微生物处理，可产生小分子（例如嘌呤）， 促进伤口愈合和炎症消退。 该提案将在经验丰富的赞助商的指导下提供出色的指导和培训 在严格的基础科学实验室的理想环境中，该实验室与临床充分整合，同时拥有 完成该项目各个方面所需的资源和指导，包括内部的指导团队 粘膜炎症计划该培训将培养申请人的独立科学研究技能。 从事跨领域工作，推进组织损伤修复和新疾病靶标识别的治疗。