title: LTD₄ induces HB-EGF-dependent CXCL8 release through EGFR activation in human bronchial epithelial cells.
abstract: Airway epithelial cells release proinflammatory mediators that may contribute to airway remodeling and leukocyte recruitment. We explored the hypothesis that leukotriene D₄ (LTD₄) may trigger the release of proremodeling factors through activation of the EGF receptor (EGFR). We particularly focused on the effects of LTD₄ on release of heparin-binding EGF-like factor (HB-EGF) and IL-8 (CXCL8), a potent neutrophil chemoattractant that may be released downstream of EGFR activation. To address this hypothesis, both primary (NHBE) and transformed bronchial human epithelial cells (BEAS-2B) were grown on an air-liquid interface and stimulated with LTD₄. HB-EGF and CXCL8 were evaluated by ELISA in cell culture supernatants. To explore the EGFR signaling pathway, we used a broad-spectrum matrix metalloproteinase (MMP) inhibitor, GM-6001, two selective EGFR tyrosine kinase inhibitors, AG-1478 and PD-153035, an HB-EGF neutralizing antibody, and a specific small interfering RNA (siRNA) against the EGFR. Expression of the CysLT₁ cysteinyl leukotriene receptor was demonstrated by RT-PCR and immunocytochemistry in both BEAS-2B and NHBE cells. Four hours after stimulation with LTD₄, HB-EGF and CXCL8 were significantly increased in cell culture supernatant. GM-6001 and montelukast, a specific CysLT₁ receptor antagonist, blocked the LTD₄-induced increase in HB-EGF. All inhibitors/antagonists decreased LTD₄-induced CXCL8 release. siRNA against EGFR abrogated CXCL8 release following stimulation with LTD₄ and exogenous HB-EGF. These findings suggest LTD₄ induced EGFR transactivation through the release of HB-EGF in human bronchial epithelial cells with downstream release of CXCL8. These effects may contribute to epithelial-mediated airway remodeling in asthma and other conditions associated with cysteinyl leukotriene release.
authors.affiliation: Department of Medicine, McGill University, Montréal, Québec, Canada.
authors.forename: Toby
authors.initials: T
authors.lastname: McGovern
authors.forename: Paul-André
authors.initials: PA
authors.lastname: Risse
authors.forename: Kimitake
authors.initials: K
authors.lastname: Tsuchiya
authors.forename: Muhannad
authors.initials: M
authors.lastname: Hassan
authors.forename: Gerard
authors.initials: G
authors.lastname: Frigola
authors.forename: James G
authors.initials: JG
authors.lastname: Martin
mesh_terms: D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism*; D066257:Heparin-binding EGF-like Growth Factor; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D016209:Interleukin-8 / Q000378:metabolism*; D017998:Leukotriene D4 / Q000378:metabolism / Q000494:pharmacology*; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D020545:Respiratory Mucosa / Q000166:cytology*
chemical_list: C587883:HBEGF protein, human; D066257:Heparin-binding EGF-like Growth Factor; D036341:Intercellular Signaling Peptides and Proteins; D016209:Interleukin-8; D034741:RNA, Small Interfering; D017998:Leukotriene D4; D066246:ErbB Receptors