Fig. 1

Bronchial smooth muscle cell (BSMC) expression of IL-33 is induced by epithelial conditioned media and further enhanced by dsRNA. To establish an optimal concentration of epithelial conditioned media, BSMCs from healthy subjects were stimulated with different dilutions of conditioned media from either non-treated (cond med) or dsRNA-treated (dsRNA-cond med) bronchial epithelial cells and mRNA expression of IL-33 was analysed by RT-qPCR after 3 and 24 h (a, b). IL-33 expression after stimulation with 10 μg/ml dsRNA alone or in combination with epithelial conditioned media was analysed in both healthy (c, d) and asthmatic (e, f) BSMCs. Epithelial basal medium diluted 1:10 in BSMC medium was used as vehicle control. Data are presented as mean with SEM and n = 3–6 independent experiments from three BSMC donors. *p ≤ 0.05, **p ≤ 0.01 and ***p ≤ 0.001 compared to vehicle if not otherwise indicated