TNF-alpha Modulation of Intestinal Epith. Permeability

描述(申请人提供)：克罗恩病(CD)患者具有缺陷的肠上皮紧密连接(TJ)屏障，表现为肠道通透性增加。肠上皮TJ屏障的缺陷可能是CD的一个重要致病因素，它允许有毒的肠腔抗原和物质进入肠道，导致肠道炎症。肿瘤坏死因子-α(TNF-α)在CD的肠道炎症中起中心作用。最近的几项研究，包括我们的初步研究表明，肿瘤坏死因子-α可持续增加肠上皮细胞的通透性。肿瘤坏死因子-α诱导的肠上皮细胞TJ通透性增加可能是一种重要的促炎机制，使有毒管腔抗原在肠道的渗透增加。由于肿瘤坏死因子-α在CD的肠道炎症中起核心作用，了解肿瘤坏死因子-α诱导的肠道TJ通透性增加所涉及的细胞内机制对于开发潜在的治疗策略以防止肠道TJ通透性的异常增加至关重要。在这项拨款申请中，我们建议使用Caco-2肠道上皮细胞来描述介导肿瘤坏死因子-α诱导的肠道TJ通透性增加的细胞和分子机制。根据我们的初步数据，我们假设，肿瘤坏死因子-α诱导的核因子-kappaB的激活是一个关键的细胞内过程，调节肿瘤坏死因子-α对肠上皮TJ屏障的调节。这项赠款申请的拟议特定目标将检验这一假设，即核因子-B的激活是调节肿瘤坏死因子-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。所提出的特异性目标还将1)阐明调节肿瘤坏死因子-α诱导的核因子-kappaB激活和肠上皮细胞通透性增加的细胞内机制，2)确定肿瘤坏死因子-α调节TJ蛋白的分子和细胞机制，以及3)确定可能的细胞内靶点，以防止肿瘤坏死因子-α诱导的肠上皮通透性增加。

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.