Figure 12.

CBF measurements of nasal epithelial cells exposed to apical or basolateral 2FLI. a and b, representative traces of CBF with 2FLI ± carbenoxolone (100 μm; 30 min preincubation). Control cultures (day 25 at ALI) exhibited no increased CBF with apical (ap.) 2FLI application but an ∼50% increase in CBF with basolateral (bl.) 2FLI. CBX did not inhibit effects of basolateral 2FLI. c, representative trace of ∼50% increase in CBF with apical 2FLI in IL-13–treated ALI (21 days differentiation then 4 subsequent days with IL-13). d–f, representative traces showing CBF in the presence of gap junction inhibitors CBX (d and e) or Gap 27 (f; 10 μm; 30 min pretreatment) in cultures treated with IL-13. Apical 2FLI responses were blocked, but basolateral 2 FLI (d) or apical ATP (e and f) responses were intact. g, bar graph showing peak normalized CBF with agonist as used in a–f. Control cultures are shown in green, and IL-13 cultures are shown in magenta. Each data point is an independent ALI culture from a separate individual patient (n = 5 per condition). Significance was determined by one-way ANOVA with Bonferroni post-test; **, p < 0.01 between bracketed values. h and i, schematic of PAR-2 regulation of ciliary function in well-differentiated epithelium (modeled by control cultures; h) versus remodeled epithelium (modeled by IL-13 stimulated cultures; i). Data support that basolateral PAR-2 is expressed under both conditions and can regulate CBF directly within ciliated cells. Apical PAR-2 is not expressed in ciliated cells, but apical PAR-2 stimulation can transmit signals (likely calcium, Ca²⁺) to ciliated cells through gap junctions. h and i created with Biorender.com.