In experiments aimed to investigate the role of extracellular ATP release in virus-induced mucin production, suramin (a non-selective P2R antagonist, TOCRIS) was added to basal media at 10 μM for 30 min prior to HRV treatment. To investigate the ability of tiotropium and fluticasone to inhibit ATP- induced mucin expression, cells pre-treated with tiotropium/fluticasone were stimulated with 100 μM ATP at the basal side for 24 h.
In experiments with DAPT (γ-secretase inhibitor, TOCRIS), ALI-PBEC were incubated in complete medium supplemented with either 5 μM DAPT or solvent control (0.1% DMSO) during differentiation for 14 days. On day 14, cells were infected with HRV-A16 at MOI 1, and following infection the basal medium was replaced by fresh HC-free medium containing 5 μM DAPT or solvent control and cells were incubated for another 24 h.