Figure 7.

Epithelial remodeling is associated with enhanced fluid secretion to apical PAR-2 stimulation. a, representative orthogonal confocal sections of control cultures with Texas Red dextran-labeled ASL showing increase in ASL height (reflecting fluid secretion) with basolateral but not apical 2FLI (∼25 μm). b, representative sections of IL-13–treated cultures showing increased secretion with either basolateral or apical 2FLI and inhibition by the CaCC inhibitor CaCC_inh-A01 (∼10 μm). c, peak ASL heights from independent experiments, each the average of 10 ASL measurements from one ALI; there were six experiments per condition. Note no inhibition of secretion with CFTR_inh172 (∼10 μm), but there was inhibition with NKCC1 inhibitor bumetanide (100 μm) or PAR-2 antagonist FSLLRY-NH₂ (∼10 μm). Drugs applied to the apical (ap.) side were sonicated in perfluorocarbon to not disturb the aqueous ASL layer; thus, apical concentrations are approximate. d, data experiments using ΔF508/ΔF508 homozygous CF ALIs. Note no response in CF cultures to basolateral (bl.) forskolin (20 μm), which elevates cAMP and activates CFTR (non-CF cultures responded in c). Each point is an independent experiment using cells from one patient (five patients total). e, experiments similar to c were performed ± PAR-2 antagonist FSLLRY-NH₂ to demonstrate PAR-2 specificity of the response in both apical and basolateral 2FLI exposure. Each point is an independent experiment using an ALI culture from one patient (four to six ALIs from four to six patients per condition). Significance was determined in c–e by one-way ANOVA with Dunnett's post-test; **, p < 0.01 versus control (no stim) for each condition.