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.

项目摘要由克罗恩病和溃疡性结肠炎组成的炎症性肠病（IBD）是一种慢性复发影响140万美国人的疾病，其中估计有600名每10万名退伍军人吸收不良，血腥腹泻，狭窄，瘘管和感染。另外，慢性炎症状态与非IBD相比患者。免疫疗法越来越有效；但是，难治性疾病和缓解不好理解。我的长期目标是将我在上皮细胞生物学方面运用我的专业知识，以了解肠上皮形成对微生物的有效屏障。该提议的目的是了解肠道的显微镜表面结构被破坏并有助于IBD发病机理和细菌感染。肠内衬里的上皮细胞位于肠道的界面微生物和肠道相关的免疫系统。肠细胞是最丰富的细胞类型，被涂覆具有〜2000个小型头发蛋白的微绒毛（MV），可促进营养吸收并充当来自肠道内部数百万细菌的保护屏障。 MV是接触的初始站点在肠上皮细胞和腔细菌之间。 MV结构和密度的扰动导致在IBD中看到的营养不良吸收和渗透性腹泻以及致病性细菌感染。最近研究表明，即使在未发炎的组织中，克罗恩病的患者的MV结构水平较低蛋白质。这些发现暗示MV缺陷不仅存在于主动炎症期间的IBD中，而且持续存在尽管治疗，并且可能有助于继电器。有趣的是，我们的初步数据表明，缺乏的小鼠 MV结构蛋白CDHR2概括了克罗恩患者中看到的几种上皮缺陷，提供了独特的体内模型系统。在此提案中，我们将测试正常肠球菌缺陷的假设根尖表面结构和功能在没有主动感染的情况下持续存在，并为微生物进入感染，感染和疾病缓解。在AIM 1中，我们将使用Crohn的病人活检组织和患者干细胞衍生的肠肠todin胶，以表征基本的超微结构克罗恩病中存在的缺陷。在AIM 2中，我们将挑战CDHR2肠敲除老鼠和克罗恩患者干细胞的肠道肠肠over脚杆菌核杆菌和粪肠球菌感染以评估MV结构缺陷对防御细菌的功能后果感染/定植，对结肠炎的敏感性以及响应炎症的愈合。完成这些研究，我们将确定克罗恩患者的肠肠细胞结构缺陷，并表征了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为治疗干预提供了新的目标。最后，通过这些研究，一位有前途的年轻医生科学家将获得有关肠道感染和细菌感染的基本和翻译研究的新技能在高度成就的上皮生物学专家委员会的指导下，宿主 - 微生物相互作用和炎症。这些新的修补技能将为这个大三的基础奠定基础研究人员要实现长期目标，成为一名独立资助的学术医师科学家。