Neuropeptides SP and CGRP Diminish the Moraxella catarrhalis Outer Membrane Vesicle- (OMV-) Triggered Inflammatory Response of Human A549 Epithelial Cells and Neutrophils

Figure 2

Modulation of hBD-2 promoter activity in human lung epithelial cells A549 by M. catarrhalis outer membrane vesicles (OMVs) and neuropeptides. Stimulant concentration: (a) the indicated cytokine concentrations are given in ng/ml, (b) the indicated concentrations of OMVs are given in μg/ml, whereas IL-1β in ng/ml (c) stimulants were used at the following concentrations: IL-1β (1 ng/ml), OMVs (2 μg/ml), SP, and CGRP (10⁻⁸ M). The cell line was transfected with luciferase reporter vector containing the hBD-2 promoter (hBD-2-pGL4[luc2]) and incubated with stimulants. (a) Kinetics of cytokine-dependent hBD-2 expression. (b) IL-1β-induced hBD-2 expression in cells stimulated by M. catarrhalis OMVs; compared with cells stimulated only with IL-1β or the corresponding concentrations of OMVs alone. (c) Neuropeptide-dependent decrease of IL-1β-induced hBD-2 expression in cells stimulated by M. catarrhalis OMVs; compared with cells stimulated simultaneously with OMVs and IL-1β. Data are expressed as the -fold increase in luciferase activity measured in RLU/s relative to unstimulated control. Error bars indicate the SEM of the mean values obtained from two (a, b) and at least three (c) independent experiments performed in duplicate. Differences between luciferase activities were analyzed by one-way ANOVA followed by Tukey’s post hoc test.

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