LL-37 induces the release of neutrophil-chemotatic factors from airway epithelial cells during infection with P. aeruginosa.

A) Representative examples of neutrophil migration assayed in ChemoTx chambers. Human neutrophils were assayed migrating towards chambers containing filtered conditioned supernatant from NHBE cells treated for 3 hours with media only (untreated control), 20 μg/ml LL-37, 20 μg/ml ScrLL-37, PAO1 at 10:1 MOI, PAO1 + LL-37 or PAO1 + ScrLL-37. Migrated cells were stained with 1 μM Calcein AM for 15 minutes at 37˚C, and imaged by microscopy. B) Quantitation of migrating neutrophils shown in A, expressed as fold change compared to untreated control. Data represent means +/- SEM from n = 3–6 separate experiments performed with neutrophils isolated from a different donor for each experiment, *** p < 0.001, ** p<0.01, * p < 0.05 versus PAO1 + LL-37 condition, by 2-way ANOVAs with Bonferroni Post-test, to examine the effect of PAO1 infection, with or without LL-37, or scrLL-37 treatment. ns = no significant difference.