Microbiota based mechanisms of post-infection irritable bowel syndrome

感染后肠易激综合征的微生物群机制

基本信息

批准号：
10675635
负责人：
Madhusudan Grover
金额：
$ 34.98万
依托单位：
MAYO CLINIC ROCHESTER
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-09-21 至 2026-07-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10675635
关键词：
Acute Adult Affect Automobile Driving Bacteria Bacteroides Beta-glucuronidase Bilirubin Biological Markers Campylobacter jejuni Chronic Colon Communities Coupled Data Development Diarrhea Engraftment Enterocolitis Enzymes Escherichia coli Family Feces Functional disorder Funding Germ-Free Health Healthcare Systems Human Human Activities Impairment In Vitro Infection Intervention Intestines Irritable Bowel Syndrome Link Longitudinal Studies Mediating Mediator Metabolism Metagenomics Microbe Morbidity - disease rate Mus Pathway interactions Patients Peptide Hydrolases Play Population Prevotella Protease Inhibitor Proteins Regulation Regulation of Proteolysis Risk Risk Factors Role Sampling Serine Protease Serine Proteinase Inhibitors Source Structure Symptoms Testing Tight Junctions Time Transplantation commensal microbes disabling symptom dysbiosis efficacy evaluation enteric infection experimental study fecal microbiota gut bacteria gut microbiota human microbiota humanized mouse improved in vivo inhibitor intestinal barrier metaproteomics microbial microbial community microbiota mouse model overexpression restoration

项目摘要

ABSTRACT One in six adults in the U.S. suffers from chronic and often disabling symptoms of irritable bowel syndrome (IBS). Intestinal infections are an established risk-factor for development of post-infection IBS (PI-IBS). The intestinal tract contains a variety of proteases, and we have discovered that PI-IBS patients have significantly higher fecal proteolytic activity (PA) than controls. More importantly, PA associates strongly with loss of intestinal barrier function and worse symptoms for the patients. We found that patients who develop PI-IBS and have high PA have a significant loss of microbial diversity that starts soon after the infection. Key microbial taxa are lost, especially from the Alistipes genus. Using metaproteomics, we found that proteases driving PA in these patients are of human origin. In order to understand if loss of microbiota could be affecting host proteases, we used germ-free mice. Colonization of germ-free mice with healthy human microbiota (humanization) results in a significant decline of PA suggesting commensal microbes inhibit host proteases and thus have a role in maintaining intestinal health. However, the dysbiotic microbiota from the high PA patients that are missing specific microbes were unable to suppress PA. We hypothesize that Alistipes and other missing bacteria play a critical role in suppression of PA. We plan to test the candidate bacteria identified in the preliminary experiments and inter-species interactions in PA regulation in Aim 1. Next, we determined how loss of microbes result in poor inhibition of proteases. Unconjugated bilirubin is an inhibitor of serine proteases and microbial β-glucuronidases deconjugate bilirubin. We found that the PI-IBS patients with high PA have lower fecal microbial β-glucuronidase enzymatic activity. Additionally, they have lower levels of end products of bilirubin deconjugation. β-glucuronidases are a large family of microbial enzymes with varying sources, structures and catalytic efficacies for different substrates. We hypothesize that loss of specific microbial β-glucuronidases will result in impaired deconjugation of bilirubin. In Aim 2, we will analyze metagenomics data from our PI-IBS patients with high and low PA for presence of microbial β-glucuronidases as well as determine the efficacy of these fecal samples for bilirubin deconjugation. Additionally, we will generate purified β-glucuronidases from Alistipes and other bacterial taxa for assessing bilirubin deconjugation efficacy in vitro. Next, we have shown that fecal microbiota transfer using an Alistipes enriched low PA community can suppress PA in high PA humanized mice providing a rationale for using microbiota for protease suppression and correcting intestinal barrier function. In Aim 3, we will use cohousing strategies to allow microbiota transfer between humanized high and low PA mice and determine if barrier dysfunction associated with a high PA state can be reversed. Furthermore, we will determine changes in barrier pathways, ionic selectivity and expression of tight junction proteins upon engraftment of new microbiota. Together, these aims will examine microbial influence on PI-IBS pathophysiology via regulation of intestinal proteases. Identification of microbiota-based strategies that can result in protease inhibition and restoration of barrier function can be beneficial for IBS and other conditions associated with microbial dysbiosis.

抽象的在美国，六分之一的成年人患有慢性且常常致残的肠易激综合症症状 (IBS)。肠道感染是感染后 IBS (PI-IBS) 发生的既定危险因素。肠道内含有多种蛋白酶，我们发现PI-IBS患者有明显的比对照组更高的粪便蛋白水解活性 (PA) 更重要的是，PA 与粪便蛋白水解活性的丧失密切相关。我们发现发生 PI-IBS 的患者的肠道屏障功能和症状更差。具有高 PA 的微生物多样性在感染后不久就开始显着丧失。类群丢失，特别是来自 Alistipes 属，我们使用宏蛋白质组学发现驱动 PA 的蛋白酶。这些患者是人类来源的，以便了解微生物群的丧失是否会影响宿主。蛋白酶，我们使用了带有健康人类微生物群的无菌小鼠。（人源化）导致 PA 显着下降，表明共生微生物抑制宿主蛋白酶从而在维持肠道健康方面发挥作用。然而，高 PA 导致的菌群失调。缺少特定微生物的患者无法抑制 PA。其他缺失的细菌在抑制 PA 中发挥着关键作用，我们计划测试已确定的候选细菌。在目标 1 中 PA 调节的初步实验和物种间相互作用中。接下来，我们确定微生物的损失如何导致蛋白酶抑制不良。非结合胆红素是丝氨酸的抑制剂。我们发现PI-IBS患者体内的蛋白酶和微生物β-葡萄糖醛酸酶可解结合胆红素。 PA 的粪便微生物 β-葡萄糖醛酸酶活性较低，此外，它们的末端水平也较低。胆红素解结合产物是一大类具有不同性质的微生物酶。我们考虑了不同底物的来源、结构和催化功效。微生物 β-葡萄糖醛酸酶会导致胆红素解离受损。在目标 2 中，我们将进行分析。来自高 PA 和低 PA 的 PI-IBS 患者的微生物 β-葡萄糖醛酸酶存在的宏基因组学数据以及确定这些粪便样本对胆红素解离的功效。从 Alistipes 和其他细菌分类群中产生纯化的 β-葡萄糖醛酸酶，用于评估胆红素解结合接下来，我们证明了使用 Alistipes 富集低 PA 的粪便微生物群转移。群落可以抑制高 PA 人源化小鼠中的 PA，为使用微生物群作为蛋白酶提供了理论基础在目标 3 中，我们将使用共同饲养策略来抑制和纠正肠道屏障功能。人源化高 PA 小鼠和低 PA 小鼠之间的微生物群转移，并确定屏障功能障碍是否相关具有高 PA 状态的情况可以逆转此外，我们将确定屏障途径、离子的变化。这些目标共同实现了新微生物群植入后紧密连接蛋白的选择性和表达。将通过调节肠道蛋白酶鉴定来检查微生物对 PI-IBS 病理生理学的影响。基于微生物群的策略可以抑制蛋白酶并恢复屏障功能对肠易激综合症和其他与微生物失调相关的疾病有益。