ABSTRACT
BACKGROUND: Coronavirus 229E (HCoV-229E), one of the causes of the common cold, exacerbates chronic obstructive pulmonary disease (COPD) and bronchial asthma. Long-acting muscarinic antagonists and ß2-agonists and inhaled corticosteroids inhibit the exacerbation of COPD and bronchial asthma caused by infection with viruses, including HCoV-229E. However, the effects of these drugs on HCoV-229E replication and infection-induced inflammation in the human airway are unknown. METHODS: Primary human nasal (HNE) and tracheal (HTE) epithelial cell cultures were infected with HCoV-229E. RESULTS: Pretreatment of HNE and HTE cells with glycopyrronium or formoterol decreased viral RNA levels and/or titers, the expression of the HCoV-229E receptor CD13, the number and fluorescence intensity of acidic endosomes where HCoV-229E RNA enters the cytoplasm, and the infection-induced production of cytokines, including IL-6, IL-8, and IFN-ß. Treatment of the cells with the CD13 inhibitor 2'2'-dipyridyl decreased viral titers. Pretreatment of the cells with a combination of three drugs (glycopyrronium, formoterol, and budesonide) exerted additive inhibitory effects on viral titers and cytokine production. Pretreatment of HNE cells with glycopyrronium or formoterol reduced the susceptibility to infection, and pretreatment with the three drugs inhibited activation of nuclear factor-kappa B p50 and p65 proteins. Pretreatment with formoterol increased cAMP levels and treatment with cAMP decreased viral titers, CD13 expression, and the fluorescence intensity of acidic endosomes. CONCLUSIONS: These findings suggest that glycopyrronium, formoterol, and a combination of glycopyrronium, formoterol, and budesonide inhibit HCoV-229E replication partly by inhibiting receptor expression and/or endosomal function and that these drugs modulate infection-induced inflammation in the airway.