Laboratory of Allergology and Pulmonary Diseases, Dept of Pathology and Medical Biology,University Medical Center Groningen, University of Groningen, Hanzeplein 1, NL-9713 GZ Groningen, The Netherlands.
Eur Respir J. 2010 Nov;36(5):1016-26. doi: 10.1183/09031936.00125809. Epub 2010 Mar 29.
Impaired airway epithelial barrier function has emerged as a key factor in the pathogenesis of allergic asthma. We aimed to discern the involvement of the epidermal growth factor receptor (EGFR) in allergen-induced epithelial barrier impairment, as we previously observed that house dust mite (HDM) signals through EGFR. We investigated the junctional integrity of human bronchial epithelial cells using electric cell-substrate impedance sensing and immunofluorescent staining. HDM induced a rapid, transient fall in epithelial resistance, concomitant with delocalisation of E-cadherin and zona occludens (ZO)-1, and proteolytic cleavage of the latter. EGFR inhibition by AG1478 reduced the HDM-triggered decrease in epithelial resistance and improved restoration of epithelial junctions. Similarly, AG1478 increased epithelial barrier recovery upon electroporation-induced injury, although it delayed the migration phase of the wound healing response. HDM-promoted redistribution of E-cadherin was mediated via EGFR-dependent activation of protease-activated receptor (PAR)-2, while the concomitant ZO-1 degradation was PAR-2/EGFR-independent. Importantly, the fibrogenic cytokine transforming growth factor (TGF)-β prolonged HDM-induced EGFR phosphorylation and inhibited ligand-induced EGFR internalisation/degradation, which resulted in sustained E-cadherin and ZO-1 redistribution. Thus, allergen-induced, PAR-2/EGFR-mediated signalling decreases epithelial resistance and promotes junction disassembly. The TGF-β-enhanced EGFR signalling may be an important contributor to barrier dysfunction and increased epithelial vulnerability in response to HDM.
气道上皮屏障功能障碍已成为变应性哮喘发病机制中的一个关键因素。我们旨在探讨表皮生长因子受体 (EGFR) 在变应原诱导的上皮屏障损伤中的作用，因为我们之前观察到屋尘螨 (HDM) 通过 EGFR 发出信号。我们使用电细胞-底物阻抗传感和免疫荧光染色来研究人支气管上皮细胞的连接完整性。HDM 诱导上皮电阻迅速、短暂下降，同时 E-钙粘蛋白和封闭蛋白 (ZO)-1 去定位，并发生后者的蛋白水解切割。EGFR 抑制剂 AG1478 减少了 HDM 触发的上皮电阻下降，并改善了上皮连接的恢复。同样，AG1478 增加了电穿孔诱导损伤后上皮屏障的恢复，尽管它延迟了伤口愈合反应的迁移阶段。HDM 促进 E-钙粘蛋白重新分布是通过 EGFR 依赖性激活蛋白酶激活受体 (PAR)-2 介导的，而同时发生的 ZO-1 降解与 PAR-2/EGFR 无关。重要的是，成纤维细胞生长因子转化生长因子 (TGF)-β 延长了 HDM 诱导的 EGFR 磷酸化，并抑制了配体诱导的 EGFR 内化/降解，导致持续的 E-钙粘蛋白和 ZO-1 重新分布。因此，变应原诱导的、PAR-2/EGFR 介导的信号降低了上皮电阻并促进了连接解体。TGF-β 增强的 EGFR 信号可能是对 HDM 反应中屏障功能障碍和上皮易损性增加的重要贡献。
