Abstract
An impaired epithelial barrier is often observed in allergic rhinitis (AR), which facilitates the infiltration of allergens. The aim of this study was to investigate the role of autophagy in the impaired epithelial barrier in AR and the related signalling pathways. A human nasal epithelial cell line was treated with dust mite allergen (Derp1). Autophagy was evaluated by GFP-LC3 adenovirus transfection and measurement of autophagy-related proteins. Epithelial barrier function was evaluated by measuring tight junction protein expression, transepithelial electrical resistance, and fluorescein isothiocyanate-dextran (FD4) permeability. Next, miR-125b inhibitor, miR-125b mimics, shRNA targeting FoxP3, pcDNA3.1 expressing FoxP3, and inhibitor of C-X-C motif chemokine receptor type 4 (CXCR4) were used to investigate the roles of miR-125b, FoxP3, and CXCR4 in epithelial cell autophagy and epithelial barrier function. An in vivo AR model was generated by exposing rat nasal mucosa to an allergen. Derp1 exposure enhanced autophagy and impaired the epithelial barrier in epithelial cells. Upregulation of miR-125b expression led to enhanced autophagy and impaired epithelial barrier through inhibition of FoxP3. Derp1 exposure increased miR-125b expression by increasing the expression and activation of CXCR4, which downregulated FoxP3 expression and led to enhanced autophagy and an impaired epithelial barrier. In vivo analysis confirmed the role of the CXCR4/miR-125b/FoxP3 axis in the impaired epithelial barrier in AR. This study demonstrates that the CXCR4/miR-125b/FoxP3 axis may participate in the pathogenesis of AR by regulating autophagy in epithelial cells and dysfunction of the epithelial barrier.