title: Human airway trypsin-like protease induces amphiregulin release through a mechanism involving protease-activated receptor-2-mediated ERK activation and TNF alpha-converting enzyme activity in airway epithelial cells.
abstract: Human airway trypsin-like protease (HAT), a serine protease found in the sputum of patients with chronic airway diseases, is an agonist of protease-activated receptor-2 (PAR-2). Previous results have shown that HAT enhances the release of amphiregulin (AR); further, it causes MUC5AC gene expression through the AR-epidermal growth factor receptor pathway in the airway epithelial cell line NCI-H292. In this study, the mechanisms by which HAT-induced AR release can occur were investigated. HAT-induced AR gene expression was mediated by extracellular signal-regulated kinase (ERK) pathway, as pretreatment of cells with ERK pathway inhibitor eliminated the effect of HAT on AR mRNA. Both HAT and PAR-2 agonist peptide (PAR-2 AP) induced ERK phosphorylation; further, desensitization of PAR-2 with a brief exposure of cells to PAR-2 AP resulted in inhibition of HAT-induced ERK phosphorylation, suggesting that HAT activates ERK through PAR-2. Moreover, PAR-2 AP induced AR gene expression subsequent to protein production in the cellular fraction through the ERK pathway indicating that PAR-2-mediated activation of ERK is essential for HAT-induced AR production. However, in contrast to HAT, PAR-2 AP could not cause AR release into extracellular space; it appears that activation of PAR-2 is not sufficient for HAT-induced AR release. Finally, HAT-induced AR release was eliminated by blockade of tumour necrosis factor alpha-converting enzyme (TACE) by the TAPI-1 and RNA interference, suggesting that TACE activity is necessary for HAT-induced AR release. These observations show that HAT induces AR production through the PAR-2 mediated ERK pathway, and then causes AR release by a TACE-dependent mechanism.
authors.affiliation: Pharmaceutical Discovery Research Laboratories, Institute for Bio-Medical Research, Teijin Pharma Limited, Tokyo, Japan. m.chiyotsuki@teijin.co.jp
authors.forename: Manabu
authors.initials: M
authors.lastname: Chokki
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Eguchi
authors.forename: Ichiro
authors.initials: I
authors.lastname: Hamamura
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Mitsuhashi
authors.forename: Takashi
authors.initials: T
authors.lastname: Kamimura
mesh_terms: D051722:ADAM Proteins / Q000378:metabolism*; D000072198:ADAM17 Protein; D066258:Amphiregulin; D002460:Cell Line; D066255:EGF Family of Proteins; D004847:Epithelial Cells / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D006023:Glycoproteins / Q000378:metabolism*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D010766:Phosphorylation; D044464:Receptor, PAR-2 / Q000819:agonists / Q000378:metabolism*; D012137:Respiratory System / Q000166:cytology*; D012697:Serine Endopeptidases / Q000502:physiology*; D015398:Signal Transduction; D014162:Transfection
chemical_list: C587848:AREG protein, human; D066258:Amphiregulin; D066255:EGF Family of Proteins; D006023:Glycoproteins; D036341:Intercellular Signaling Peptides and Proteins; D044464:Receptor, PAR-2; D048049:Extracellular Signal-Regulated MAP Kinases; D012697:Serine Endopeptidases; C112256:human airway trypsin-like protease; D051722:ADAM Proteins; D000072198:ADAM17 Protein; C000606462:ADAM17 protein, human