Anion Transport in EPEC Induced Diarrhea

描述(由申请人提供)： 目前的申请旨在为首席调查员提供宿主-微生物相互作用领域的深入培训，以及研究生一级的正规课程，以加强她的研究和实验室技能。发起人和共同发起人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，为首席调查员提供了一个很好的培训机会，以实现她成为宿主-微生物相互作用领域的独立研究调查员的长期目标。这些研究的重点是研究阴离子转运在一种重要的食源性致病大肠杆菌(EPEC)感染相关腹泻的病理生理学中的作用。到目前为止，EPEC相关性腹泻的发病机制(S)尚不清楚。腹泻是由于分泌物增加或吸收减少或两者兼而有之。早期的研究未能得出结论，表明EPEC感染会增加宿主的分泌反应。我们推测，EPEC引起的腹泻可能涉及肠道离子吸收过程的减少。我们的初步数据显示，EPEC感染后，CI‘-OH’交换活性、丁酸转运和Na+吸收异构体NHE3下降。本研究将在体外和体内模型中探讨EPEC感染对Cl‘-OH’交换活性的影响，并阐明鲁米那阴离子交换器DRA(SLC26A3)和PAT-1(SLC26A6)的作用。具体目的1的研究将确定肠上皮细胞(EPEC)在模型人小肠(CaCO-2)和结肠(T84和未转化的NCM460)上皮细胞中对氯离子转运的影响，并阐明信号机制(S)、肠上皮细胞毒力基因的作用以及肠上皮细胞介导的氯离子转运的动力学参数。具体目的2将利用siRNA技术来确定DRA和PAT-1在调节CI‘-OH’交换反应EPEC感染中的作用。具体目标3将利用EPEC感染的小鼠体内模型，关键地研究EPEC对CI在回肠和结肠中的转运的影响。这些研究结果不仅将加深我们对人类肠道Cl‘-OH’交换器的调节机制以及病原体对其调节的了解，而且还将为EPEC引起的腹泻的发病机制提供基础，这可能有助于未来改进的治疗方法的开发。

DESCRIPTION (provided by applicant): The current application is aimed at providing the Principal Investigator with in-depth training in the area of host-microbial interactions along with formal courses at the graduate level to enhance her research and laboratory skills. The expertise of the sponsor and co-sponsor combined with a highly interactive basic-research environment at the Department of Medicine at University of Illinois at Chicago, offer a great training opportunity for the Principal Investigator to achieve her long-term goals in becoming an independent research investigator in the area of host- microbial interactions. The proposed studies are focused to examine the role of anion transport 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 diarrhea are not clear. Diarrhea results from increased secretion or decreased absorption or both. Earlier studies have failed to conclusively show an increase in host secretory responses by EPEC infection. We hypothesized that EPEC-induced diarrhea might involve a decrease in intestinal ion absorptive processes. Our preliminary data showed a decrease in CI'-OH' exchange activity, butyrate transport and Na+ absorbing isoform, NHE3 in response to EPEC infection. The present studies will explore the effects of EPEC infection on Cl'-OH' exchange activity in both in vitro and in vivo models and elucidate the contribution of luminal anion exchangers, DRA (SLC26A3) and PAT-1 (SLC26A6). Studies in Specific Aim 1 will determine the effects of EPEC on Cl' transport in model human small intestinal (Caco-2) and colonic (T84 and non-transformed NCM460) epithelia; along with elucidation of signaling mechanism(s), role of EPEC virulence genes and kinetic parameters of EPEC mediated effects on Cl' transport. Specific Aim 2 will utilize siRNA technology to define the role of DRA and PAT-1 in modulation of CI'-OH' exchange in response to EPEC infection. Specific Aim 3 will critically examine the effects of EPEC on CI' transport in ileum and colon 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 Cl'-OH' exchangers and their modulation by pathogenic organisms, but will also provide basis for the pathogenesis of EPEC-induced diarrhea which might aid in the development of improved therapeutic modalities in future.