Regulation of Paracellular Permeability by IFNy and TNFa

IFNγ和TNFa对细胞旁通透性的调节

• 批准号: 7027748
• 负责人: JERROLD R. TURNER
• 金额: $ 35万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-07-01 至 2010-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7027748
• 关键词: T lymphocyte; actins; biological signal transduction; cell line; cytokine receptors; enzyme induction /repression; fluorescence recovery after photobleaching; gastrointestinal absorption /transport; gastrointestinal epithelium; genetic regulation; genetic transcription; genetically modified animals; interferon gamma; laboratory mouse; leukocyte activation /transformation; muscle contraction; myosin light chain kinase; myosins; phosphorylation; protein localization; receptor expression; tight junctions; tumor necrosis factor alpha

DESCRIPTION (provided by applicant): Loss of epithelial barrier function is characteristic of inflammatory, infectious, ischemic, and immune mediated intestinal diseases. Synergistic signaling between the TH1 cytokines interferon-gamma (IFNgamma) and tumor necrosis factor-alpha (TNFalpha), which are frequently elevated in these diseases, has been implicated in this barrier dysfunction. In turn, compromised barrier function can allow noxious nominal material to access the lamina propria, stimulate immune cells, and augment IFNgamma and TNFalpha release, culminating in a self-amplifying cycle of epithelial dysfunction. In vivo data show that barrier dysfunction can be reversed by anti-TNF a therapies. We have recently shown that IFN gamma / TNFalpha -induced loss of barrier function is related to increased myosin light chain (MLC) phosphorylation and that both loss of barrier function and increased MLC phosphorylation can be reversed by a novel oligopeptide MLC kinase inhibitor. Despite this, the mechanisms by which IFNgamma / TNFalpha increase MLC phosphorylation and decrease barrier function are not well understood. Characterization of these regulatory mechanisms is important to understanding the pathogenesis of diverse intestinal diseases and may also identify novel targets for therapy of IFNgamma / TNFalpha -driven intestinal disease. This may lead to the development of effective non-immunosuppresive therapies for diseases such as Crohn's disease, enteric infection, ischemia-reperfusion injury, and graft versus host disease. The central hypothesis of this proposal is that IFNgamma and TNFalpha synergize to activate a signaling cascade that results in increased TNF receptor expression, increased MLC kinase expression, increased MLC phosphorylation, tight junction reorganization, and epithelial barrier dysfunction. The aims of this application are to test this hypothesis by i) determining the role of IFNgamma in enhancing epithelial responsiveness to TNFalpha and the mechanisms by which IFNgamma and TNalpha synergize to increase MLC phosphorylation, ii) defining the effects of IFNgamma and TNFalpha on tight junction protein dynamics using integrated functional, biochemical, and real time imaging approaches, and iii) exploring the effects of IFNgamma and TNFalpha on the regulation of MLC phosphorylation in vivo using knockout mice and pharmacologic agents that prevent IFNgamma / TNFalpha -induced barrier dysfunction in vitro. We expect that these studies will have significant positive effects on human health because they will lead to the development of new understanding of the mechanisms by which barrier function is compromised in disease and will provide the foundation necessary for the development of strategies for enhancement of barrier function as a therapeutic modality.

描述（由申请人提供）：上皮屏障功能的丧失是炎症，传染性，缺血和免疫介导的肠道疾病的特征。 Th1细胞因子干扰素 - γ（IFNGAMMA）和肿瘤坏死因子-Alpha（TNFalpha）之间的协同信号传导在这些疾病中经常升高，这与这种障碍功能障碍有关。反过来，受损的屏障功能可以允许有害的名义材料进入固有层，刺激免疫细胞，并增强Ifngamma和Tnfalpha释放，并在上皮功能障碍的自我扩增循环中达到顶点。体内数据表明，抗TNF A疗法可以逆转屏障功能障碍。我们最近表明，IFNγ / TNFalpha诱导的屏障功能丧失与肌球蛋白轻链（MLC）磷酸化的增加有关，并且屏障功能的丧失和MLC磷酸化均可通过新型的寡肽MLC MLC激酶抑制剂来反转。尽管如此，尚不清楚IFNGAMMA / TNFALPHA增加MLC磷酸化和降低屏障功能的机制。这些调节机制的表征对于理解各种肠道疾病的发病机制很重要，并且还可以鉴定出治疗IFNGAMMA / TNFALPHA驱动肠道疾病的新靶标。这可能会导致开发有效的非免疫药物疗法，例如克罗恩病，肠道感染，缺血 - 再灌注损伤以及移植物与宿主疾病。该提案的中心假设是IFNGAMMA和TNFALPHA协同激活信号级联反应，从而导致TNF受体表达增加，MLC激酶表达增加，MLC磷酸化增加，紧密连接的重组和上皮屏障功能障碍。 The aims of this application are to test this hypothesis by i) determining the role of IFNgamma in enhancing epithelial responsiveness to TNFalpha and the mechanisms by which IFNgamma and TNalpha synergize to increase MLC phosphorylation, ii) defining the effects of IFNgamma and TNFalpha on tight junction protein dynamics using integrated functional, biochemical, and real time imaging方法，以及iii）探索使用基因敲除小鼠和药理剂和药物学剂，探索IFNGAMMA和TNFALPHA对MLC磷酸化调节的影响，从而阻止IFNGAMMA / TNFALPHA诱导的屏障诱导的障碍物在体内的影响。我们预计这些研究将对人类健康产生重大的积极影响，因为它们将导致对障碍功能在疾病中受到损害的机制的新理解的发展，并为发展势垒功能作为治疗方式的发展提供了必要的基础。