Fig. 4

Blocking purinergic signalling inhibits BSMC expression of IL-33 induced by dsRNA and epithelial condition medium. BSMCs were stimulated with 10 μg/ml dsRNA for 5–60 min and ATP was analysed in cell supernatants and data related to that of control samples (a). ATP release was also measured in BSMC supernatants 24 h after RV-infection (b). BSMC expression of IL-33 mRNA was analysed by RT-qPCR 24 h after stimulation with non-hydrolysable ATP (ATP-γ-S) (c). The effect of the purinergic inhibitor suramin (Sur) on dsRNA-induced IL-33 expression was evaluated at both mRNA (d) and protein (e) levels with RT-qPCR and western blot respectively. ATP was measured in bronchial epithelial conditioned medium (n = 4 donors) and compared to non-conditioned medium (control) (f) and the effect of suramin on conditioned medium-induced IL-33 mRNA (g) was analysed 24 h after stimulation. Data are presented as mean with SEM and n = 2–6 independent experiments from two or three BSMC donors. *p ≤ 0.05, **p ≤ 0.01, and ***p ≤ 0.001 compared to control if not otherwise indicated and ^### p ≤ 0.001 compared to 10 μg/ml dsRNA. A representative western blot image of IL-33 is shown