Intestinal Bile Acid Transport in EPEC Infection

EPEC 感染中的肠道胆汁酸转运

• 批准号: 7499688
• 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/7499688
• 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）：当前的建议旨在为候选人提供在宿主微生物互动领域的深入培训，以及研究生层面的正式课程，以增强其研究和实验室技能。赞助商和共同赞助商的专业知识与芝加哥伊利诺伊大学医学系高度互动的基础研究环境相结合，为申请人提供了一个很棒的培训机会，以实现他成为独立的长期目标研究研究者在胃肠道生理学方面特别重视基础研究。拟议的研究集中于研究肠道顶端钠依赖性胆汁酸转运蛋白（ASBT）在与重要食品传播病原体（EPEC）感染相关的腹泻病理生理学中的作用。迄今为止，尚不清楚与EPEC相关的早期腹泻的机制尚不清楚。在这方面，负责吸收大多数胆汁酸的ASBT已与与炎症性疾病相关的腹泻有关。 ASBT功能的干扰与小肠和结肠中的腔胆浓度增加有关，这又会影响电解质的吸收和分泌，从而导致腹泻。因此，我们假设EPEC诱导的腹泻可能涉及肠道胆汁酸转运过程的减少。我们的初步数据显示，人类肠道CACO-2细胞单层中EPEC感染的响应响应ASBT功能降低。本研究将探索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。特定目标1中的研究将确定EPEC对模型人类小肠（CACO-2单层）中ASBT活性的影响，并研究EPEC毒力基因的作用和EPEC介导的ASBT活性作用的动力学参数。具体目标2将阐明EPEC诱导的信号转导途径和膜运输事件的作用，涉及ASBT功能和表达的调节。特定的目标3将使用EPEC感染的体内鼠模型进行批判性检查EPEC及其突变体对回肠胆酸转运的影响。这些研究的结果不仅会增加我们对人肠胆汁酸转运蛋白调节机制的理解及其通过致病生物的调节，而且还将为EPEC诱导的腹泻发病提供基础，这可能有助于改善的发展。将来的治疗方式。