Thioredoxin Mediates Remodeling Factors of Human Bronchial Epithelial Cells upon Interaction with House Dust Mite-Stimulated Eosinophils

Abstract

Bronchial epithelial cells exposed to allergens typically secrete chemokines to recruit eosinophils. Persistent inflammation and repair responses result in airway remodeling and irreversible airflow limitation. House dust mite (HDM) is a common allergen causing allergic disorders. Thioredoxin (TRX) is a redox protein that scavenges reactive oxygen species (ROS). This study was to elucidate how TRX mediates gene expression of remodeling factors of human bronchial epithelial cells in response to HDM stimuli interacting with eosinophils. This study cultured normal human bronchial epithelial (BEAS-2B) cells with eosinophils exposed to 0.5 μg/ml recombinant Dermatophagoides pteronyssinus 1 (rDer p1) protease to mimic the allergen-immune reaction. Eosinophils were induced by rDer p1 protease to secrete tumor necrosis factor (TNF)-α and generate ROS. When cultured with rDer p1-stimulated eosinophils, BEAS-2B cells released interleukin-6 and underwent apoptosis. The HDM-stimulated eosinophils applied oxidative stress and apoptosis to BEAS-2B cells through the release of mediators. Damaged BEAS-2B cells interfered with gene expression of remodeling factors, such as transforming growth factor (TGF)-β 1, epidermal growth factor receptor (EGFR), cyclin dependent kinase inhibitor (p21^waf) and matrix metalloproteinase (MMP) 9, relevant to inflammatory response and epithelial repair in airway remodeling. Notably, BEAS-2B cells over-expressing TRX reduced eosinophil-derived apoptosis and suppressed underlying airway remodeling via attenuation of TGF-β1, EGFR and p21^waf and up-regulation of MMP9 expression. Results of this study indicated TRX-over-expressing bronchial epithelial cells attenuated TGF-β1 and activated MMP9 expression to prevent airway remodeling from HDM-induced inflammation. The finding can be as a reference for further therapeutic studies of TRX.