Regulation of Intestinal Transport

总体描述（由申请人提供）： 本计划项目的总体目标是了解肠道病原体和炎症介质感染时肠道电解质和溶质转运失调的机制。为此，组成该计划的四个项目中的每一个都涉及肠道运输的一个组成部分，无论是吸收，分泌还是被动的细胞旁运动。项目1将研究一种重要的肠道病原体，肠致病性E。项目2将主要关注Na+/H+交换剂（NHEs）对钠吸收的影响;项目3将研究甘丙肽受体表达和激活对肠道细菌病原体（包括沙门氏菌和EPEC）的氯化物分泌的作用;项目4将研究炎症介质（LIGHT和IFN）对肠道紧密连接通透性的影响。各个项目彼此之间以及核心之间紧密结合。三个核心（核心A -成像;核心B -电生理学/细胞培养;核心C -给药）旨在满足项目的总体需求。将使用广泛的方法来解决一系列问题，从关键转运蛋白的转录调控和细菌病原体对每种主要转运模式的影响，到引起这种变化的特定因素和信号通路。拟议的项目将采用相同的体外和体内模型系统、培养的人肠上皮细胞单层和小鼠模型，以及广泛的实验方法来评估转运活性，包括电生理测量、放射性同位素和荧光离子转运活性测定、细胞成像、分子生物学和生物化学技术。调查将扩大到选择敲除小鼠在三个项目。这些项目一起使用凝聚和互补的方法，解决了在常见的病理条件下，肠道炎症和感染性腹泻的肠道运输（吸收，分泌和紧密连接渗透性）的主要成分的调节。

DESCRIPTION, OVERALL (provided by applicant): The overall goal of this Program Project is to understand the mechanisms that underlie the dysregulation of electrolyte and solute transport in the intestine in the face of infection by enteric pathogens and inflammatory mediators. To this end, each of the four projects comprising this Program address one component of intestinal transport, either absorption, secretion, or passive paracellular movement. Project 1 will investigate the effects of an important enteric pathogen, enteropathogenic E. coli, on sodium absorption via Na+/H+ exchangers (NHEs); Project 2 will focus primarily on the transcriptional regulation of NHEs; Project 3 will investigate the role galanin receptor expression and activation on chloride secretion in response to enteric bacterial pathogens including Salmonella and EPEC; and Project 4 will address the effects of inflammatory mediators (LIGHT and IFN() on intestinal tight junction permeability. The individual projects are closely integrated with each other and the Cores. The three Cores (Core A - Imaging; Core B - Electrophysiology/Cell Culture; and Core C - Administration) were designed to fit the overall needs of the Program. A broad spectrum of approaches will be used to address a continuum of issues ranging from transcriptional regulation of key transporters and the influence of bacterial pathogens on each of the major modes of transport, to specific factors and signaling pathways involved in evoking such changes. The proposed projects will employ the same in vitro and in vivo model systems, cultured human intestinal epithelial monolayers and mouse models, and a broad range of experimental approaches to assess transport activity including electrophysiologic measurements, radioisotope and fluorometric ion transporter activity assays, cell imaging, molecular biological and biochemical techniques. Investigations will extend to select knock out mice in three of the projects. Together the projects, using cohesive and complementary approaches, address the regulation of the major components of intestinal transport (absorption, secretion, and tight junction permeability) under commonly encountered pathological conditions, intestinal inflammation and infectious diarrhea.