Fusarium species are causative agents of human respiratory disorders and are distributed widely in our environment. Little is known of their interaction with human respiratory epithelial cells, which may contribute to allergic airway responses. In this study, we report on the release of C-X-C motif chemokine ligand 8 (CXCL-8) from human bronchial epithelial BEAS-2B cells upon stimulation with Fusarium proliferatum extracts. F. proliferatum-induced cytokine release from BEAS-2B cells was determined by cytokine array and CXCL-8 enzyme-linked immunosorbent assay (ELISA) kits. Blocking antibodies and signaling pathway inhibitors were employed to delineate cell surface receptors and signaling pathways participating in CXCL-8 release. F. proliferatum extracts induced the release of CXCL-8 in a time-dependent manner. The dectin-1 receptor ligands, curdlan and laminarin, reduced CXCL-8 release. Cells pre-treated with anti-Dectin-1 antibodies (2 µg/mL) decreased CXCL-8 release by 24%. Furthermore, F. proliferatum-stimulated CXCL-8 release was reduced by 32%, 53%-81%, 40% and 26% after BEAS-2B cells were pretreated with activation inhibitors of spleen tyrosine kinase (Syk)-piceatannol-, mitogen-activated protein kinases (MAPKs)-PD98059, U0126, SB202190, SP600125-, phosphatidylinositol-3-kinase (PI3K)-LY294002-and nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB)-BAY117082-, respectively. These results suggest that Dectin-1-mediated activation of the Syk, MAPKs, PI3K and NF-κB signaling pathways contributes to F. proliferatum-stimulated CXCL-8 release from BEAS-2B cells and provides an important basis for developing novel therapeutic strategies in clinical allergy.
Keywords: CXCL-8; Dectin-1; Fusarium proliferatum; respiratory epithelial cells.