Pharmacological modulation of interleukin-17-induced GCP-2-, GRO-alpha- and interleukin-8 release in human bronchial epithelial cells.

The cytokine interleukin-17 may play a role in the recruitment of airway neutrophils, and interleukin-17 protein is increased in the airways of patients with asthma. In this study, we characterised the effect of interleukin-17 on the release of the neutrophil-recruiting cytokines granulocyte chemotactic protein (GCP)-2, growth-related oncogene (GRO)-alpha and interleukin-8 in human bronchial epithelial (HBE) cells. We also characterised the involvement of mitogen-activated protein (MAP) kinases as well as the effect of beta-adrenoceptor and glucocorticoid receptor stimulation and calcineurin and P-glycoprotein inhibition on these epithelial responses to interleukin-17. We found that interleukin-17 (1-1000 ng/ml) increased the release of GCP-2, GRO-alpha and interleukin-8 in a concentration-dependent manner. This interleukin-17-induced release of C-X-C chemokines was sensitive to inhibition of the p38 MAP kinase pathway and to stimulation of glucocorticoid receptors. In contrast, stimulation of beta-adrenoceptors increased the release of interleukin-8 and did not markedly alter the release of GCP-2 and GRO-alpha. Inhibition of calcineurin and of P-glycoproteins did not exert any substantial effect on the release of C-X-C chemokines. In conclusion, interleukin-17 bears the potential to increase neutrophil recruitment into the airways by releasing several, different C-X-C chemokines, including GCP-2, GRO-alpha and interleukin-8 in human bronchial epithelial cells. Inhibition of the p38 MAP kinase pathway and glucocorticoid receptor stimulation constitute two credible therapeutic strategies against this interleukin-17-induced release of neutrophil-recruiting cytokines.