Characterization of human airway epithelial cell lines as in vitro models of chronic obstructive pulmonary disease

Airway epithelial cells produce mucus to protect against toxic agents and pathogens. However, when the mucus accumulates can become pathological – a characteristic of chronic obstructive pulmonary disease (COPD). The effectiveness of inhaled drugs is reduced by excess mucus and the effectiveness of gene vectors delivered to the airways is decreased by the presence of a viscous mucus barrier. The objective of the present study was to develop an in vitro model capable of cytokine production and mucus secretion to test new drugs. Then, we stimulated three different human airway epithelial cell lines (A549, Calu-3, and NCI-H292) with various concentrations of cigarette smoke extract (CSE) alone or in association with lipopolysaccharide (LPS). In Calu-3, any stimulation did not affect MUC5AC and cytokine gene expression or protein secretion. In contrast, A549 exposure to CSE and LPS was associated with greater release of IL-8/CXCL8, GRO-α/CXCL1 and MCP-1/CCL2 proteins, but not on mucus production. However, for NCI-H292, CSE alone was associated with elevated mucus production, and an additive effect was observed when CSE was combined with LPS (except for MCP-1/CCL2). Lastly, in the NCI H292 and Calu-3 co-culture, the combination of CSE and LPS was associated with greater MUC5AC gene expression and LPS was associated with greater secretion of only IL-8/CXCL8. Our results indicate that NCI-H292 cells constitute the most appropriate in vitro model for studying inflammatory mediator secretion and mucus production as a guide to the efficacy of new mucolytic drug candidates and gene therapy vectors.