TNF-alpha Regulation of Intestinal Paracellular Transport

TNF-α 肠道旁细胞转运的调节

• 批准号: 7728315
• 负责人: THOMAS Y MA
• 金额: $ 36.15万
• 依托单位: UNIVERSITY OF NEW MEXICO
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-06-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7728315
• 关键词: Antibodies; Antigens; Applications Grants; Biological Models; Biological Preservation; Cell physiology; Clinical; Crohn' s disease; Defect; Development; Disease; Down-Regulation; Epithelial; Epithelial Cells; Gene Expression; Gene Proteins; Genes; In Vitro; Inflammation; Inflammation Process; Inflammatory; Inflammatory Response; Inflammatory disease of the intestine; Intestines; Laboratories; Lead; MAP Kinase Activation Pathway; MAPK11 gene; MAPK8 gene; Maintenance; Mediating; Membrane; Messenger RNA; MicroRNAs; Mitogen-Activated Protein Kinase 3; Molecular; Mus; Myosin Light Chain Kinase; Pathway interactions; Patients; Perfusion; Permeability; Phosphotransferases; Play; Process; Proteins; Regulation; Resolution; Role; Signal Transduction; Stream; System; Testing; Therapeutic; Therapeutic Agents; Tight Junctions; Time; Treatment Efficacy; Tumor Necrosis Factor-alpha; Tumor Necrosis Factors; Up-Regulation; base; clinical remission; cytokine; human TNF protein; in vivo; in vivo Model; insight; mRNA Expression; mitogen-activated protein kinase p38; mouse model; novel; occludin; prevent; protein expression; public health relevance; therapeutic target

DESCRIPTION (provided by applicant): Intestinal paracellular transport or paracellular permeation in-between intestinal epithelial cells is regulated by tight junctions. Patients with Crohn's disease (CD) have a defective intestinal tight junction (TJ) barrier, manifested by an increase in paracellular permeability. The defective intestinal TJ barrier is an important pathogenic factor of CD that allows increased paracellular permeation of toxic luminal antigens, leading to intestinal inflammation. Tumor necrosis factor-1 (TNF-1), a pro-inflammatory cytokine, has been shown to play a central role in the intestinal inflammation process of CD. An important pro-inflammatory action of TNF-1 is to cause a functional opening of the intestinal TJ barrier, leading to an increase in paracellular permeation of noxious luminal antigens. The TNF-1 induced increase in intestinal paracellular permeability has been postulated to be an important mechanism contributing to the intestinal TJ barrier defect in CD and other inflammatory conditions of the gut. The broad objectives of this grant proposal are to elucidate the cellular and molecular mechanisms that mediate the TNF-1 induced increase in intestinal TJ permeability and to determine the potential therapeutic targets to prevent the TNF-1 induced defect in TJ barrier and subsequent development of intestinal inflammation. To achieve these objectives, we intend to use both in-vitro (consisting of filter-grown Caco-2 intestinal epithelial cells) and in-vivo (mouse intestinal perfusion system) model systems. Our preliminary studies suggested that the TNF-1 induced increase in intestinal epithelial TJ permeability was regulated in part by ERK 1/2 and p38 signaling cascade induced increase in myosin light chain kinase (MLCK) gene activity and microRNA induced down-regulation of occludin gene expression. Based on our preliminary studies, we advance a novel hypothesis that the TNF-1 induced increase in intestinal TJ permeability is mediated in part by ERK1/2 and p38 signaling cascade induced activation of MLCK gene and modulation of microRNA expression. The proposed specific aims are to: 1) elucidate the intracellular and the molecular processes that mediate the TNF-1 induced increase in MLCK gene activity and intestinal TJ permeability; 2) delineate the cellular and molecular mechanisms that mediate the TNF-1 induced down- regulation of occludin gene and protein expression; and 3) delineate the mechanisms involved in TNF-1 induced increase in intestinal permeability in-vivo and determine the therapeutic implications of targeted preservation of TJ barrier function in TNF-1 induced intestinal inflammation. PUBLIC HEALTH RELEVANCE: Patients with Crohn's disease have a leaky gut, characterized by an increase in intestinal permeability to harmful antigens in the intestinal lumen. The studies proposed in this grant application seek to provide novel insight into the cellular processes that lead to the leaky gut of Crohn's disease. These studies also seek to identify potential therapeutic targets and strategies to induce therapeutic re-tightening or normalization of leaky gut in Crohn's disease.

描述（由申请人提供）：肠上皮细胞之间的肠旁细胞转运或旁细胞渗透是由紧密连接调节的。克罗恩病 (CD) 患者的肠道紧密连接 (TJ) 屏障存在缺陷，表现为细胞旁通透性增加。肠道 TJ 屏障缺陷是 CD 的重要致病因素，可增加有毒管腔抗原的细胞旁渗透，导致肠道炎症。肿瘤坏死因子-1 (TNF-1) 是一种促炎细胞因子，已被证明在 CD 的肠道炎症过程中发挥核心作用。 TNF-1 的一个重要促炎作用是引起肠道 TJ 屏障的功能性开放，导致有害管腔抗原的细胞旁渗透增加。 TNF-1 诱导的肠道旁细胞通透性增加被认为是导致 CD 和其他肠道炎症条件下肠道 TJ 屏障缺陷的重要机制。该拨款提案的主要目标是阐明介导 TNF-1 诱导的肠道 TJ 通透性增加的细胞和分子机制，并确定潜在的治疗靶点，以防止 TNF-1 诱导的 TJ 屏障缺陷和随后肠道炎症的发展。为了实现这些目标，我们打算使用体外（由过滤器生长的 Caco-2 肠上皮细胞组成）和体内（小鼠肠道灌注系统）模型系统。我们的初步研究表明，TNF-1 诱导的肠上皮 TJ 通透性增加部分受到 ERK 1/2 和 p38 信号级联诱导的肌球蛋白轻链激酶 (MLCK) 基因活性增加和 microRNA 诱导的 occludin 基因表达下调的调节。基于我们的初步研究，我们提出了一个新的假设，即 TNF-1 诱导的肠道 TJ 通透性增加部分是由 ERK1/2 和 p38 信号级联诱导的 MLCK 基因激活和 microRNA 表达调节介导的。提出的具体目标是： 1）阐明介导 TNF-1 诱导 MLCK 基因活性和肠道 TJ 通透性增加的细胞内和分子过程； 2) 描述介导TNF-1诱导occludin基因和蛋白表达下调的细胞和分子机制； 3) 描述TNF-1诱导体内肠道通透性增加的机制，并确定在TNF-1诱导的肠道炎症中靶向保护TJ屏障功能的治疗意义。公共卫生相关性：克罗恩病患者患有肠漏症，其特点是肠道对肠腔中有害抗原的通透性增加。本拨款申请中提出的研究旨在为导致克罗恩病肠漏的细胞过程提供新的见解。这些研究还试图确定潜在的治疗靶点和策略，以诱导克罗恩病漏肠的治疗重新收紧或正常化。