Intestinal Bile Acid Transport in EPEC Infection

EPEC 感染中的肠道胆汁酸转运

• 批准号: 7333017
• 负责人: Fadi Annaba
• 金额: $ 5.89万
• 依托单位: UNIVERSITY OF ILLINOIS AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-08-16 至 2010-08-15
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7333017
• 关键词: ASBT protein; Acute; Address; Affect; Area; Bacteria; Basic Science; Bile Acids; Bile fluid; Caco-2 Cells; Cells; Characteristics; Chicago; Colon; Data; Depth; Development; Diarrhea; Disease; Electrolytes; Endocytosis; Environment; Epithelial; Epithelial Cells; Event; Exocytosis; Experimental Models; Functional disorder; Future; Gastrointestinal Physiology; Genes; Genus Cola; Goals; Housing; Human; Illinois; In Vitro; Infantile Diarrhea; Infection; Inflammatory; Intestines; Invasive; Ions; Kinetics; Knowledge; Laboratory Research; Lesion; Mediating; Medicine; Membrane; Membrane Protein Traffic; Modality; Modeling; Molecular; Morbidity - disease rate; Mus; Organism; Pathogenesis; Pathway interactions; Physiology; Process; Proteins; Regulation; Research; Research Design; Research Personnel; Role; Signal Pathway; Signal Transduction; Signal Transduction Pathway; Small Intestines; System; Therapeutic; Time; Training; Transport Process; Type III Secretion System Pathway; Universities; Virulence; absorption; apical membrane; base; bile acid transporter; design; enteric pathogen; enteropathogenic Escherichia coli; fatty acid transport; foodborne; foodborne pathogen; ileum; improved; in vivo; in vivo Model; insight; microbial; microorganism interaction; monolayer; mortality; mutant; response; skills; trafficking

DESCRIPTION (provided by applicant): The current proposal is aimed at providing the candidate with an in-depth training in the area of host- microbial interactions along with formal courses at the graduate level to enhance his research and laboratory skills. The expertise of the sponsor and co-sponsor combined with a highly interactive basic- research environment in the Department of Medicine at the University of Illinois at Chicago, offer a great training opportunity for the applicant to achieve his long-term goals of becoming an independent research investigator in gastrointestinal physiology with special emphasis on basic research. The proposed studies are focused at examining the role of intestinal apical sodium-dependent bile acid transporter (ASBT) in the pathophysiology of diarrhea associated with infection by an important food-borne pathogen, Enteropathogenic E. coli (EPEC). To date, the mechanism(s) underlying EPEC-associated early diarrhea are not clear. In this regard, ASBT which is responsible for the absorption of the majority of bile acids from the intestinal lumen, has been implicated in diarrhea associated with inflammatory diseases. Disturbances in ASBT function have been associated with increased luminal bile concentration in the small intestine and colon, which in turn can influence electrolyte absorption and secretion, causing diarrhea. Therefore, we hypothesized that EPEC-induced diarrhea might involve a decrease in intestinal bile acid transport processes. Our preliminary data showed a decrease in ASBT function in response to EPEC infection in human intestinal Caco-2 cell monolayers. The present studies will explore the effects of EPEC infection on ASBT activity and expression both in in vitro and in vivo models and elucidate the signal transduction and underlying membrane trafficking events. Studies in Specific Aim 1 will determine the effects of EPEC on ASBT activity in model human small intestinal (Caco-2 monolayers) along with investigating the role of EPEC virulence genes and kinetic parameters of EPEC mediated effects on ASBT activity. Specific Aim 2 will elucidate the role of EPEC induced signal transduction pathways and membrane trafficking events involved in modulation of ASBT function and expression. Specific Aim 3 will critically examine the effects of EPEC and its mutants on bile acid transport in the ileum utilizing the in vivo murine model of EPEC infection. The results from these studies will not only increase our understanding of the mechanisms of regulation of human intestinal bile acid transporters and their modulation by pathogenic organisms but will also provide a basis for the pathogenesis of EPEC-induced diarrhea which might aid in the development of improved therapeutic modalities in future.

描述（由申请人提供）：当前提案旨在为候选人提供宿主-微生物相互作用领域的深入培训以及研究生级别的正式课程，以提高他的研究和实验室技能。申办者和共同申办者的专业知识与伊利诺伊大学芝加哥分校医学系高度互动的基础研究环境相结合，为申请人提供了绝佳的培训机会，以实现成为独立科学家的长期目标胃肠生理学研究人员，特别注重基础研究。拟议的研究重点是检查肠顶端钠依赖性胆汁酸转运蛋白（ASBT）在与重要食源性病原体肠病性大肠杆菌（EPEC）感染相关的腹泻病理生理学中的作用。迄今为止，EPEC 相关早期腹泻的机制尚不清楚。在这方面，ASBT 负责从肠腔吸收大部分胆汁酸，它与炎症性疾病相关的腹泻有关。 ASBT 功能紊乱与小肠和结肠内胆汁浓度增加有关，这反过来又会影响电解质的吸收和分泌，导致腹泻。因此，我们推测 EPEC 引起的腹泻可能与肠道胆汁酸转运过程的减少有关。我们的初步数据显示，人肠道 Caco-2 单层细胞中 EPEC 感染导致 ASBT 功能下降。目前的研究将探讨 EPEC 感染对体外和体内模型中 ASBT 活性和表达的影响，并阐明信号转导和潜在的膜运输事件。具体目标 1 的研究将确定 EPEC 对人类小肠模型（Caco-2 单层）中 ASBT 活性的影响，同时研究 EPEC 毒力基因的作用和 EPEC 介导的 ASBT 活性影响的动力学参数。具体目标 2 将阐明 EPEC 诱导的信号转导途径和膜运输事件在 ASBT 功能和表达调节中的作用。具体目标 3 将利用 EPEC 感染的体内鼠模型严格检查 EPEC 及其突变体对回肠胆汁酸转运的影响。这些研究的结果不仅将增加我们对人类肠道胆汁酸转运蛋白的调节机制及其受病原微生物调节的了解，而且还将为 EPEC 诱导的腹泻的发病机制提供基础，这可能有助于开发改进的方法。未来的治疗方式。