EGFR activation-induced decreases in claudin1 promote MUC5AC expression and exacerbate asthma in mice.

Claudin1 plays a critical role in maintaining the epithelial barrier, and mucus hypersecretion induced by epidermal growth factor receptor (EGFR) activation is a pivotal pathological feature of asthma. The relationship between claudin1 expression and mucus hypersecretion and EGFR activation is still poorly understood. In this report, we showed that claudin1 expression correlated with asthma stage, in both patients with asthma and in the house dust mite (HDM)-induced mouse asthma model. Claudin1 knockdown induced MUC5AC overexpression both in 16HBE cells and in mouse airways. In addition, claudin1 expression negatively correlated with asthma severity as demonstrated by significantly higher MUC5AC expression, more severe airway inflammation, and increased airway hyperreactivity in mouse lungs with claudin1 knockdown following HDM challenge. EGFR activation reduced claudin1 expression and increased MUC5AC expression, both in vitro and in vivo. Erlotinib alleviated murine allergic airway inflammation, restored claudin1 expression and decreased MUC5AC expression. These results suggest that EGFR activation-induced decreases in claudin1 promote goblet-cell metaplasia, and restoring claudin1 to maintain barrier integrity by EGFR antagonism may provide a novel therapeutic strategy for asthma.