TNF-alpha Modulation of Intestinal Epith. Permeability

描述（由申请人提供）：克罗恩病（CD）患者有肠上皮紧密连接（TJ）屏障缺陷，表现为肠通透性增加。有缺陷的肠上皮TJ屏障似乎是CD的一个重要致病因素，它允许有毒的腔内抗原和物质渗透肠道，导致肠道炎症。肿瘤坏死因子- α (Tumor necrosis factor- α, tnf - α)在CD的肠道炎症中起着核心的致病作用。最近的一些研究包括我们的初步研究表明，tnf - α可导致肠上皮TJ通透性持续增加。tnf - α诱导的肠上皮TJ通透性增加可能是一个重要的促炎机制，它允许有毒腔内抗原增加肠通透性。由于TNF- α在CD的肠道炎症中起核心作用，了解TNF-诱导肠道TJ通透性增加的细胞内机制对于制定潜在的治疗策略以防止肠道TJ通透性异常增加至关重要。在这项拨款申请中，我们建议使用Caco-2肠上皮细胞来描述介导tnf - α诱导的肠道TJ通透性增加的细胞和分子机制。基于我们的初步数据，我们假设tnf - α诱导的NF-kappaB激活是一个关键的细胞内过程，该过程调节了tnf - α对肠上皮TJ屏障的调节。这项拨款申请的具体目的是验证NF-(B)激活是调节tnf - α诱导的肠上皮TJ（或细胞旁）通透性增加的关键细胞内过程的假设。提出的具体目标还将1)描述调节tnf - α诱导的NF-kappaB激活和肠上皮TJ通透性增加的细胞内机制，2)确定tnf - α调节TJ蛋白的分子和细胞机制，以及3)确定治疗干预的可能细胞内靶点，以防止tnf - α诱导的肠TJ通透性增加。

DESCRIPTION (provided by applicant): Patients with Crohn's disease (CD) have a defective intestinal epithelial tight junction (TJ) barrier manifested by an increase in intestinal permeability. The defective intestinal epithelial TJ barrier appears to be an important pathogenic factor of CD, which allows intestinal penetration of toxic luminal antigens and substances leading to the intestinal inflammation. Tumor necrosis factor-alpha (TNF-alpha) plays a central causative role in intestinal inflammation of CD. Several recent studies including our preliminary studies demonstrated that TNF-alpha produces a persistent increase in intestinal epithelial TJ permeability. The TNF-alpha induced increase in intestinal epithelial TJ permeability could be an important pro-inflammatory mechanism, which allows increased intestinal permeation of toxic luminal antigens. Since TNF-alpha plays a central role in the intestinal inflammation of CD, understanding the intracellular mechanisms involved in TNF-( induced increase in intestinal TJ permeability will be crucial in developing potential therapeutic strategies to prevent the abnormal increase in intestinal TJ permeability. In this grant application, we propose to delineate the cellular and molecular mechanisms, which mediate the TNF-alpha induced increase in intestinal TJ permeability, using the Caco-2 Intestinal epithelial cells. Based on our preliminary data, we hypothesize that TNF-alpha induced NF-kappaB activation is a key intracellular process, which regulates the TNF-alpha modulation of the intestinal epithelial TJ barrier. The proposed specific aims of this grant application will test the hypothesis that NF-(B activation is a key intracellular process regulating the TNF-alpha induced increase in intestinal epithelial TJ (or paracellular) permeability. The proposed specific aims will also 1) delineate the intracellular mechanisms which regulate the TNF-alpha induced NF-kappaB activation and increase in intestinal epithelial TJ permeability, 2) determine the molecular and cellular mechanisms by which TNF-alpha regulates the TJ proteins, and 3) determine the possible intracellular targets for therapeutic intervention to prevent the TNF-alpha induced increase in intestinal TJ permeability.