Exploring the role and mechanisms of action of UC pouchitis-associated pathobionts (PAP) to gain insights into the etiopathogenesis of Inflammatory Bowel Diseases

探索 UC 储袋炎相关病原体 (PAP) 的作用和作用机制，以深入了解炎症性肠病的发病机制

• 批准号: 10679821
• 负责人: Joash Lake
• 金额: $ 4.77万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2026-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10679821
• 关键词: 16S ribosomal RNA sequencing; Address; Affect; Agreement; Anastomosis - action; Antibiotics; Anus; Bacteroides fragilis; Biological Markers; Cell Culture Techniques; Chronic; Clinical; Colectomy; Colitis; Colon; Communities; Complex; Critical Thinking; Data; Developed Countries; Developing Countries; Development; Diet; Disease; Disease susceptibility; Engraftment; Environment; Environmental Risk Factor; Event; Excision; Experimental Models; Flow Cytometry; Frequencies; Future; Gastrointestinal tract structure; Gene Expression; Genes; Genetic; Genetic Predisposition to Disease; Germ-Free; Gnotobiotic; Goals; Human; Ileal Reservoirs; Immune; Immune response; Immunology; In Vitro; Incidence; Indigenous; Industrialization; Inflammation; Inflammatory; Inflammatory Bowel Diseases; Interleukin-10; Intestines; Knock-out; Knockout Mice; Knowledge; Large Intestine; Life Style; Mentors; Metabolic Pathway; Metagenomics; Microbe; Modeling; Mucositis; Mucous Membrane; Mus; Pathogenesis; Pathway interactions; Patients; Play; Pouchitis; Predisposition; Prevalence; Prevention strategy; Procedures; Production; Prospective Studies; Remission Induction; Research; Research Personnel; Ribosomal RNA; Risk; Risk Factors; Role; Sampling; Science; Severities; Spectrophotometry; Testing; Therapeutic; Training; Ulcerative Colitis; Volatile Fatty Acids; Wild Type Mouse; antimicrobial peptide; colon microbiota; conditioning; cytokine; dysbiosis; germ free condition; gut microbiome; gut microbiota; high risk; human model; immune activation; immunogenic; immunogenicity; improved; in vivo; inflammatory milieu; insight; knowledge base; lens; metabolomics; microbial; microbiome research; microbiota; mouse model; pathobiont; potential biomarker; risk prediction; role model; skills; theories; transcriptome sequencing

PROJECT SUMMARY/ABSTRACT Inflammatory Bowel Diseases (IBD) are a growing concern in industrialized and newly developing countries as the environment, lifestyles, and diets change. IBD involves a complex interplay between the host's environment, diet, genetics, and gut microbiota, each necessary but insufficient to cause disease. However, it is unclear what initiates these diseases, what the relative contributions of these factors play in the pathogenesis of IBD, and what makes these diseases chronic. Current therapies are still imprecise, and preventative disease strategies for high-risk patients are non-existent. Some evidence suggests that changes in the gut microbiota can influence the risk and trigger IBD. Our lab uses a human model involving ulcerative colitis(UC) patients who undergo colectomy followed by creating an ileal pouch-anal anastomosis (IPAA). In theory, IPAA should be curative, but nearly half of these patients develop an inflammatory condition of the ileal pouch called pouchitis, whereas non-IBD patients undergoing the same procedure rarely develop pouchitis. These patients were followed and sampled longitudinally, and metagenomic data shows blooms of pathobionts such as Bacteroides fragilis before and during the development of pouchitis. Upon antibiotic-induced remission, the relative abundance of B. fragilis decreased, implicating it as a potential trigger and sustainer of pouchitis. The proposed research strategy tests the hypothesis that pouchitis-associated pathobionts (PAP) like Bacteroides fragilis cause in IPAA-associated pouchitis. Notably all the B. fragilis strains cultivated from UC pouchitis patients are non-enterotoxigenic strains that were present even before the IPAA was performed. Thus, we believe that insight gained through these studies will directly relate to the etiopathogenesis of human IBD. As a counterpart to the human pouchitis model, we employ germ-free (GF) and SPF (specific pathogen-free) wild-type (WT) and IL10 knockout (IL10-/-) mice where engraftment of PAP B. fragilis in the latter is associated with increased incidence and severity of colitis. I will determine whether B. fragilis promotes colitis directly and/or indirectly by causing perturbations in the membership and function of the indigenous colonic microbiota. SPF, but not GF, IL10-/- mice are genetically predisposed to developing IBD. Human PAP B. fragilis strains readily engraft into SPF IL10-/- mouse microbiota, but not that of WT mice, and promote the development of colitis. Using Bulk-RNA Sequencing analysis and flow cytometry, I will evaluate how the presence of B. fragilis alters the host's immune responses and gene expression in the GI tract of GF and SPF IL-10-/- mice. Fecal samples, regional intestinal luminal, and mucosal content will be subjected to 16S rRNA, metagenomic, and metabolomic analyses to assess if B. fragilis leads to dysbiosis–promoting chronic colitis in the IL10-/- mouse model. This study provides critical insight into the events prior to the development of chronic inflammation in an IBD-susceptible host. In addition, these studies will shed light on potential biomarkers that can predict risk, help define preventative strategies, and guide therapeutic management.

项目总结/摘要 炎症性肠病（IBD）在工业化国家和新兴发展中国家日益受到关注， 环境、生活方式和饮食都在改变。IBD涉及宿主的免疫系统之间复杂的相互作用。 环境，饮食，遗传和肠道微生物群，每一个都是必要的，但不足以引起疾病。但 目前尚不清楚是什么引发了这些疾病，这些因素的相对贡献在这些疾病中起着什么作用。 IBD的发病机制，以及是什么使这些疾病慢性化。目前的治疗方法仍然不精确， 没有针对高危患者的预防性疾病策略。一些证据表明， 肠道微生物群中的微生物可以影响风险并引发IBD。我们的实验室使用了一个人类模型， 结肠炎（UC）患者接受结肠切除术，然后建立回肠袋-肛门吻合术（IPAA）。在 理论上，IPAA应该是治愈性的，但近一半的患者发展为回肠炎性疾病。 在某些情况下，IBD患者会出现称为结肠袋炎的结肠袋炎，而经历相同手术的非IBD患者很少发生结肠袋炎。 对这些患者进行了纵向跟踪和采样，宏基因组数据显示， 例如在结肠袋炎发展之前和期间的脆弱拟杆菌。在药物诱导后 缓解期，B的相对丰度。fragilis减少，暗示它是一个潜在的触发器和维持者， 结肠袋炎。拟议的研究策略测试的假设，结肠袋炎相关的病原体（PAP） 如脆弱拟杆菌引起的IPAA相关性结肠袋炎。尤其是所有的B。fragilis菌株培养自 UC结肠袋炎患者是非肠源性菌株，甚至在IPAA实施之前就存在。 执行。因此，我们认为，通过这些研究获得的见解将直接关系到 人IBD的发病机制。作为人类结肠袋炎模型的对应物，我们采用无菌（GF） 和SPF（无特异性病原体）野生型（WT）和IL 10敲除（IL 10-/-）小鼠，其中移植了PAP B。 后者中的脆弱性与结肠炎的发病率和严重程度增加有关。我将决定是否B。 fragilis直接和/或间接地通过引起结肠炎的成员和功能的扰动而促进结肠炎。 本地结肠微生物群SPF，而不是GF，IL 10-/-小鼠在遗传上易患IBD。 人PAP B。fragilis菌株容易植入SPF IL 10-/-小鼠微生物群，但不植入WT小鼠的微生物群， 促进结肠炎的发展。我将使用大体积RNA测序分析和流式细胞术进行评估 B. fragilis改变宿主的免疫反应和GF胃肠道中的基因表达 和SPF IL-10-/-小鼠。粪便样本、局部肠腔和粘膜内容物将进行16 S rRNA、宏基因组学和代谢组学分析以评估是否存在B. fragilis导致促进生态失调的慢性 IL 10-/-小鼠模型中的结肠炎。这项研究提供了关键的洞察事件之前的发展， IBD易感宿主的慢性炎症。此外，这些研究将揭示潜在的 生物标志物可以预测风险，帮助确定预防策略，并指导治疗管理。