title: Mold allergen, pen C 13, induces IL-8 expression in human airway epithelial cells by activating protease-activated receptor 1 and 2.
abstract: Allergenic serine proteases are important in the pathogenesis of asthma. One of these, Pen c 13, is the immunodominant allergen produced by Penicillium citrinum. Many serine proteases induce cytokine expression, but whether Pen c 13 does so in human respiratory epithelial cells is not known. In this study, we investigated whether Pen c 13 caused IL-8 release and activated protease-activated receptors (PARs) in airway epithelial cells. In airway-derived A549 cells and normal human airway epithelial cells, Pen c 13 induced IL-8 release in a dose-dependent manner. Pen c 13 also increased IL-8 release in a time-dependent manner in A549 cells. Pen c 13 cleaved PAR-1 and PAR-2 at their activation sites. Treatment with Pen c 13 induced intracellular Ca(2+) mobilization and desensitized the cells to the action of other proteases and PAR-1 and PAR-2 agonists. Moreover, Pen c 13-mediated IL-8 release was significantly decreased in Ca(2+)-free medium and was abolished by the protease inhibitors, PMSF and 4-(2-aminoethyl) benzenesulfonyl fluoride. Blocking Abs against the cleavage sites of PAR-1 and PAR-2, but not of PAR-4, inhibited Pen c 13-induced IL-8 production, as did inhibition of phospholipase C. Pen c 13 induced IL-8 expression via activation of ERK 1/2, and not of p38 and JNK. In addition, treatment of A549 cells or normal human airway epithelial cells with Pen c 13 increased phosphorylation of ERK 1/2 by a Ca(2+)-dependent pathway. These finding show that Pen c 13 induces IL-8 release in airway epithelial cells and that this is dependent on PAR-1 and PAR-2 activation and intracellular calcium.
authors.affiliation: Graduate Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Li-Li
authors.initials: LL
authors.lastname: Chiu
authors.forename: Diahn-Warng
authors.initials: DW
authors.lastname: Perng
authors.forename: Chia-Hsien
authors.initials: CH
authors.lastname: Yu
authors.forename: Song-Nan
authors.initials: SN
authors.lastname: Su
authors.forename: Lu-Ping
authors.initials: LP
authors.lastname: Chow
mesh_terms: D000485:Allergens / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000276:immunology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006801:Humans; D016209:Interleukin-8 / Q000096:biosynthesis*; D008168:Lung / Q000276:immunology*; D010407:Penicillium / Q000276:immunology*; D010766:Phosphorylation; D011480:Protease Inhibitors / Q000494:pharmacology; D044463:Receptor, PAR-1 / Q000502:physiology*; D044464:Receptor, PAR-2 / Q000502:physiology*; D010738:Type C Phospholipases / Q000502:physiology
chemical_list: D000485:Allergens; D016209:Interleukin-8; D011480:Protease Inhibitors; D044463:Receptor, PAR-1; D044464:Receptor, PAR-2; D048049:Extracellular Signal-Regulated MAP Kinases; D010738:Type C Phospholipases; D002118:Calcium