Claudin-18 deficiency in the pathogenesis of asthma

Claudin-18 缺乏症与哮喘发病机制的关系

• 批准号: 8522224
• 负责人: JAMES A FRANK
• 金额: $ 17.64万
• 依托单位: NORTHERN CALIFORNIA INSTITUTE/RES/EDU
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-15 至 2014-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8522224
• 关键词: Accounting; Acetylcholine; Address; Adrenal Cortex Hormones; Air; Antigens; Aspergillus; Asthma; Breathing; Cell Culture Techniques; Cells; Clinical Data; Collaborations; Data; Defect; Development; Disease; Disease Progression; Eosinophilia; Epithelial; Epithelial Cells; Epithelium; Exposure to; Fibrosis; Functional disorder; Future; Genes; Human; IgE; Immune; Immune response; Inflammation; Integral Membrane Protein; Interleukin-13; Interleukin-4; Knockout Mice; Label; Liquid substance; Lung; Measures; Mediating; Messenger RNA; Mus; Nature; Organ; Pathogenesis; Pathway interactions; Permeability; Phenotype; Predisposition; Property; Proteins; Role; Sampling; Severities; Steroids; Structure; Testing; Tight Junctions; Time; Tissue Banking; Tissue Banks; Tissues; Wild Type Mouse; Work; airway epithelium; airway hyperresponsiveness; airway inflammation; asthmatic patient; base; bronchial epithelium; feeding; immune activation; in vivo; knock-down; macromolecule; mouse model; novel; response; small hairpin RNA; translational study

DESCRIPTION (provided by applicant): Dysfunction of the physical barrier of the airway epithelium may contribute to the development of asthma and to disease progression. The nature and mechanisms for epithelial barrier dysfunction in asthma are incompletely understood. This is in part related to the current limited understanding epithelial tight junctions in the airways. Recent discoveries highlight the diversity of tight junction structure and function, and it is clea that tissue-specific differences in tight junction claudin proteins account for differences in epithelial barrier properties in the various tissues of the body. This proposal seeks to define for the first time the role of claudin- 18, the only lung-specific tight junction protein, in airway barier function and asthma. We have found that asthmatics have a deficiency in claudin-18 in the airway epithelium compared with healthy controls. Moreover, untreated asthmatics show an increase in airway epithelial claudin-18 expression with the initiation of steroid treatment. Consistent with this observation, our newly generated claudin-18 knock out mice show a marked susceptibility to antigen sensitization and many features of asthma. Because claudin-18 knock out mice have increased epithelial permeability and claudin-18 knock down results in increased permeability in cultured airway cells, this protein may be a critical component of the airway barrier. Loss of claudin-18 may result in increased antigen exposure and immune activation. Studies in the knock out mouse will allow us to address the hypothesis that an epithelial barrier defect is a primary contributor asthma severity. Importantly, we have also found that IL-13 induces a specific decrease in claudin-18 in primary human airway epithelial cells. Therefore, the specific loss of claudin-18 in response to IL-13 may contribute to epithelial barrie defects in asthma. We will examine the role of claudin-18 maintaining airway epithelial barrier function and determine if the loss of claudin-18 is sufficient to increase airway epithelial permeability to environmental antigen and induce a more severe asthma phenotype in the mouse model of aspergillus sensitization. In cell culture studies using primary human airway epithelial cells grown on an air-liquid interface, we will also investigate the mechanisms for the IL-13-mediated decrease in claudin-18, and the specific contribution of claudin-18 to the airway epithelial permeability barrier. In translational studies using human samples and clinical data collected by the UCSF Airway Tissue Bank, we will investigate the hypothesis that asthmatics with more severe disease have lower levels of claudin-18 and determine if claudin-18 deficiency is associated with asthma Th2 phenotype.

描述（由申请方提供）：气道上皮的物理屏障功能障碍可能导致哮喘的发生和疾病进展。哮喘中上皮屏障功能障碍的性质和机制尚不完全清楚。这部分与目前对气道上皮紧密连接的了解有限有关。最近的发现强调了紧密连接结构和功能的多样性，并且很明显，紧密连接紧密蛋白的组织特异性差异解释了身体各种组织中上皮屏障特性的差异。该提案旨在为 第一次研究了claudin- 18（唯一的肺特异性紧密连接蛋白）在气道功能和哮喘中的作用。我们发现，与健康对照组相比，哮喘患者气道上皮中的claudin-18缺乏。此外，未治疗的哮喘患者显示随着类固醇治疗的开始，气道上皮claudin-18表达增加。与该观察结果一致，我们新产生的claudin-18敲除小鼠显示出对抗原致敏的显著易感性和哮喘的许多特征。由于claudin-18敲除小鼠具有增加的上皮渗透性，并且claudin-18敲低导致培养的气道细胞中增加的渗透性，因此该蛋白质可能是气道屏障的关键组分。claudin-18的丢失可能导致抗原暴露和免疫激活增加。在基因敲除小鼠中的研究将使我们能够解决上皮屏障缺陷是哮喘严重程度的主要贡献者的假设。重要的是，我们还发现 IL-13诱导原代人气道上皮细胞中密蛋白-18的特异性减少。因此，响应于IL-13的claudin-18的特异性损失可能有助于哮喘中的上皮巴里屏障缺陷。我们将研究claudin-18维持气道上皮屏障功能的作用，并确定claudin-18的缺失是否足以增加气道上皮对环境抗原的通透性，并在曲霉菌致敏小鼠模型中诱导更严重的哮喘表型。在使用在气液界面上生长的原代人气道上皮细胞的细胞培养研究中，我们还将研究IL-13介导的claudin-18减少的机制，以及claudin-18对气道上皮通透性屏障的具体贡献。在使用UCSF气道组织库收集的人类样本和临床数据的转化研究中，我们将研究疾病更严重的哮喘患者的claudin-18水平较低的假设，并确定claudin-18缺乏是否与哮喘Th 2表型相关。