title: Involvement of Toll-like receptor 2 and epidermal growth factor receptor signaling in epithelial expression of airway remodeling factors.
abstract: Staphylococcus aureus (SA) colonization and infection is common, and may promote allergic or inflammatory airway diseases, such as asthma, cystic fibrosis, and chronic rhinosinusitis by interacting with airway epithelial cells. Airway epithelial cells not only comprise a physical barrier, but also play key roles in immune, inflammatory, repair, and remodeling responses upon encounters with pathogens. To elucidate the impact of SA on epithelial-mediated remodeling of allergic airways, we tested the hypothesis that SA can enhance the remodeling process. Normal human bronchial epithelial (NHBE) cells were stimulated with heat-killed SA (HKSA) or transforming growth factor (TGF) α. Cell extracts were collected to measure mRNA (real-time RT-PCR) and signaling molecules (Western blot); supernatants were collected to measure protein (ELISA) after 24 hours of stimulation. Epidermal growth factor receptor (EGFR) signaling inhibition experiments were performed using a specific EGFR kinase inhibitor (AG1478) and TGF-α was blocked with an anti-TGF-α antibody. HKSA induced both mRNA and protein for TGF-α and matrix metalloproteinase (MMP) 1 from NHBE cells by a Toll-like receptor 2-dependent mechanism. Recombinant human TGF-α also induced mRNA and protein for MMP-1 from NHBE cells; anti-TGF-α antibody inhibited HKSA-induced MMP-1, suggesting that endogenous TGF-α mediates the MMP-1 induction by HKSA. HKSA-induced MMP-1 expression was suppressed when a specific EGFR kinase inhibitor was added, suggesting that EGFR signaling was mediating the HKSA-induced MMP-1 release. Exposure or colonization by SA in the airway may enhance the remodeling of tissue through a TGF-α-dependent induction of MMP-1 expression, and may thereby promote remodeling in airway diseases in which SA is implicated, such as asthma and chronic rhinosinusitis.
authors.affiliation: 1 Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois; and.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Homma
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kato
authors.forename: Masafumi
authors.initials: M
authors.lastname: Sakashita
authors.forename: James E
authors.initials: JE
authors.lastname: Norton
authors.forename: Lydia A
authors.initials: LA
authors.lastname: Suh
authors.forename: Roderick G
authors.initials: RG
authors.lastname: Carter
authors.forename: Robert P
authors.initials: RP
authors.lastname: Schleimer
mesh_terms: D056151:Airway Remodeling; D002478:Cells, Cultured; D004790:Enzyme Induction; D066246:ErbB Receptors / Q000378:metabolism*; D006801:Humans; D020781:Matrix Metalloproteinase 1 / Q000235:genetics / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D020545:Respiratory Mucosa / Q000378:metabolism*; D015398:Signal Transduction; D051195:Toll-Like Receptor 2 / Q000378:metabolism*; D016211:Transforming Growth Factor alpha / Q000502:physiology
chemical_list: D016328:NF-kappa B; C495342:TLR2 protein, human; D051195:Toll-Like Receptor 2; D016211:Transforming Growth Factor alpha; C512478:EGFR protein, human; D066246:ErbB Receptors; C522360:MMP1 protein, human; D020781:Matrix Metalloproteinase 1
keywords: Staphylococcus aureus; Toll-like receptor 2; epidermal growth factor receptor; matrix metalloproteinase 1; remodeling