Long-Acting Muscarinic Antagonist for Asthma Recovers Mucus Production and Normalizes Cilia Function in Epithelium With Human Airway Basal Cells In Vitro ALI Model

Abstract RATIONALE: In the treatment strategy for asthma, the use of inhaled drugs is the first choice. Current guidelines focus on clinical symptomatic effects, but less is known about the effects on the airway epithelium of inhaled drugs that act on bronchial smooth muscle and exert their bronchodilator effects. In the present study, we used a bronchial asthma mimic model with human airway basal cell to investigate the effects, mucus cells and ciliated cells, on the airway epithelium of inhaled drugs that exertbronchodilator effects via the airway epithelium.METHODS:To assess the effects of inhaled Drugs, Long-Acting Muscarinic Antagonist (LAMA) in regulating differentiation of the human airway epithelium with bronchial asthma model induced by Interleukin (IL)-13, primary human airway basal stem/progenitor cells (BC) from nonsmokers were cultured on air-liquid interface (ALI) cultures to mimic the airway epithelium in vitro. Those specimens were analyzed by pathological and molecular biological methods, and by scanning electronmicroscopy (SEM) to study the effects of inhaled drugs on bronchial asthma models.RESULTS: Normal differentiation of mucus and ciliated cells was observed on day 14 in ALI culture of human airway BCs; increased goblet cells and decreased ciliated cells were observed in the bronchial asthma model created by addition of IL-13. The addition of LAMA showed normalized goblet cell differentiation in pathological findings. There were no significant differences in MUC5AC goblet cell (p>0.05) but increase in MUC5B goblet cell (1.2 times in gene expression, 7.7 times in protein expression, p<0.05) and ciliated cell (1.8 times in gene expression for FOXJ1, p<0.005; 1.6 times in protein expression for TUBB4, p<0.005) at the gene expression and protein level by western blotanalysis compared to control. SEM showed that the ciliated cells in the LAMA dramatically recovered better than those in control.CONCLUSIONS: Inhaled LAMA for bronchial asthma suppressed mucus production and induced ciliated cell recovery than naïve and control in airway epithelium. Therefore, inhalation of LAMA may improve bronchial asthma symptoms not only by muscarinicantagonist-induced tracheobronchial smooth muscle dilation, but also by inhibiting mucus secretion, restoring ciliated cells, and promoting sputum excretion.