The role of enterocyte apical structure in inflammatory bowel disease pathogenesis

肠上皮细胞顶端结构在炎症性肠病发病机制中的作用

基本信息

批准号：
9890480
负责人：
Leslie M Meenderink
金额：
--
依托单位：
VETERANS HEALTH ADMINISTRATION
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-04-01 至 2025-03-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/9890480
关键词：
Actins Adhesions Affect American Apical Apoptosis Architecture Area Automobile Driving Bacteria Bacterial Adhesion Bacterial Infections Biological Models Biology Biopsy Brush Border Bundling Celiac Disease Cell membrane Cell physiology Cells Cellular Structures Cellular biology Chronic Colitis Colonoscopy Colorectal Cancer Complex Crohn&apos s disease Data Defect Diarrhea Disease Enterococcus faecalis Enterocytes Epithelial Epithelial Cells Epithelium Excision Fistula Foundations Funding Fusobacterium nucleatum Goals Growth Hair Hemorrhagic colitis Homeostasis Host Defense Imaging Techniques Immune system Immunology Immunotherapy Infection Inflammation Inflammatory Inflammatory Bowel Diseases Inflammatory Response Intestinal Diseases Intestines Knockout Mice Lighting Link Malabsorption Syndromes Malignant Neoplasms Medical Membrane Mentors Mentorship Messenger RNA Microbe Microscopic Microscopy Microvillus inclusion disease Modeling Morbidity - disease rate Mucous Membrane Mus Nutrient Operative Surgical Procedures Organoids Pathogenesis Pathogenicity Patients Physicians Positioning Attribute Predisposition Proteins Recurrent disease Refractory Disease Relapse Research Personnel Risk Risk Factors Role Sampling Scanning Electron Microscopy Scientist Site Small Intestines Structural Protein Structural defect Structure Surface Survival Rate Testing Therapeutic Intervention Tissues Transmission Electron Microscopy Ulcerative Colitis Veterans Villus apical membrane cell type cellular microvillus colorectal cancer risk density experimental study gut microbiota healing host-microbe interactions improved in vivo in vivo Model inflammatory disease of the intestine intestinal epithelium microbial mortality mouse model new therapeutic target nutrient absorption outcome forecast pathogen pathogenic bacteria prevent relapse risk repaired response skills stem stem cells translational study villin

项目摘要

PROJECT SUMMARY Inflammatory bowel disease (IBD), comprised of Crohn’s disease and Ulcerative colitis, is a chronic relapsing disorder that affects 1.4 million Americans including an estimated 600 per 100,000 veterans causing malabsorption, bloody diarrhea, strictures, fistulas, and infection. In addition, the chronic inflammatory state increases the risk for colorectal cancer with poorer prognosis and reduced survival rates compared to non-IBD patients. Immunotherapy is increasingly effective; however, refractory disease and relapse are not well understood. My long-term goal is to apply my expertise in epithelial cell biology to understand how the intestinal epithelium forms an effective barrier against microbes. The goal of this proposal is to understand how the microscopic surface architecture of the gut is disrupted in and contributes to IBD pathogenesis and bacterial infection. The epithelial cells lining the intestine are positioned at the interface of the intestinal microbes and the gut-associated immune system. Enterocytes are the most abundant cell type and are coated with ~2000 small hair-like protrusions, microvilli (MV) that facilitate nutrient absorption and serve as a protective barrier from the millions of bacteria concentrated inside the gut. MV are the initial site of contact between intestinal epithelial cells and luminal bacteria. Perturbations in MV structure and density result in nutrient malabsorption and osmotic diarrhea as seen in IBD and infection with pathogenic bacteria. A recent study showed that even in uninflamed tissue, patients with Crohn’s disease have lower levels of MV structural proteins. These findings imply MV defects are not only present in IBD during active inflammation but persist despite therapy and may contribute to relapse. Interestingly, our preliminary data show that mice lacking the MV structural protein CDHR2 recapitulate several of the epithelial defects seen in Crohn’s patients, providing a unique in vivo model system. In this proposal, we will test the hypothesis that defects in normal enterocyte apical surface structure and function persist in the absence of active inflammation and provide a path for microbial entry driving inflammation, infection, and disease relapse. In Aim 1, we will use Crohn’s patient biopsy tissue and patient stem cell-derived intestinal enteroids to characterize the fundamental ultrastructural defects present in Crohn’s disease. In Aim 2, we will challenge CDHR2 intestinal knockout mice and Crohn’s patient stem cell-derived intestinal enteroids with Fusobacterium nucleatum and Enterococcus faecalis infection to assess the functional consequences of defective MV structure on defense against bacterial infection/colonization, susceptibility to colitis, and healing in response to inflammation. By the completion of these studies, we will have identified defects in enterocyte structure in Crohn’s patients and characterized how these defects contribute to persistent changes in the microbial content. These epithelial structural defects may provide a new target for therapeutic intervention. Finally, through these studies, a promising young physician scientist will gain new skills in basic and translational studies of intestinal inflammation and bacterial infection under the guidance of a highly accomplished mentorship committee of experts in epithelial biology, host- microbe interactions, and inflammation. These new mentored skills will form the foundation for this junior investigator to achieve a long-term goal to be an independently funded academic physician scientist.

项目概要炎症性肠病（IBD）由克罗恩病和溃疡性结肠炎组成，是一种慢性复发性疾病影响 140 万美国人的疾病，其中估计每 10 万退伍军人中就有 600 人患有此病吸收不良、血性腹泻、狭窄、瘘管和感染此外，还有慢性炎症状态。与非 IBD 相比，结直肠癌风险增加，预后较差，生存率降低免疫疗法越来越有效；然而，难治性疾病和复发情况不佳。我的长期目标是运用我在上皮细胞生物学方面的专业知识来了解如何肠上皮形成了有效的微生物屏障，该提案的目的是了解如何形成有效的屏障。肠道的微观表面结构被破坏并导致 IBD 发病机制肠道内壁的上皮细胞位于肠道界面。微生物和肠道相关免疫系统是最丰富的细胞类型，并且有涂层。具有约 2000 个细小的毛发状突起、微绒毛 (MV)，可促进营养吸收并充当肠道内集中的数百万细菌的保护屏障是最初的接触部位。肠上皮细胞和腔内细菌之间的 MV 结构和密度的扰动导致。营养吸收不良和渗透性腹泻，如 IBD 和病原菌感染。研究表明，即使在未发炎的组织中，克罗恩病患者的 MV 结构水平也较低这些发现表明 MV 缺陷不仅存在于活动性炎症期间的 IBD 中，而且持续存在。尽管进行了治疗，但可能会故意导致复发，但我们的初步数据表明，小鼠缺乏这种能力。 MV 结构蛋白 CDHR2 重现了克罗恩病患者中观察到的几种上皮缺陷，提供了一种独特的体内模型系统，我们将测试正常肠上皮细胞缺陷的假设。顶端表面结构和功能在没有活动性炎症的情况下持续存在，并为微生物进入导致炎症、感染和疾病复发在目标 1 中，我们将使用克罗恩病患者。活检组织和患者干细胞衍生的肠肠类，以表征基本的超微结构在目标 2 中，我们将挑战 CDHR2 肠道敲除小鼠和克罗恩病。患者干细胞衍生的含有具核梭杆菌和粪肠球菌的肠类肠杆菌感染以评估缺陷 MV 结构对细菌防御的功能影响感染/定植、结肠炎易感性以及炎症反应的愈合。通过这些研究，我们将确定克罗恩病患者肠上皮细胞结构的缺陷，并描述如何这些缺陷导致微生物含量的持续变化。这些上皮结构缺陷可能。最后，通过这些研究，一位有前途的年轻医生为治疗干预提供了新的目标。科学家将获得肠道炎症和细菌感染的基础和转化研究的新技能在上皮生物学领域卓有成就的专家指导委员会的指导下，主办这些新的指导技能将为这位三年级学生奠定基础。研究者实现成为独立资助的学术医师科学家的长期目标。