title: Regulation of endothelin-1-induced interleukin-6 production by Ca2+ influx in human airway smooth muscle cells.
abstract: Endothelin-1 is considered to be an important mediator in the pathophysiology of asthma because it induces contraction, hypertrophy, and proliferation in airway smooth muscle cells as well as inflammatory responses in the airway. Airway smooth muscle cells have been suggested to contribute to airway inflammation in asthma by producing cytokines. Nevertheless, the role of intracellular Ca(2+) signal in cytokine production in human airway smooth muscle cells is still unclear. We investigated the mechanisms by which endothelin-1 induces production of interleukin (IL)-6, a pleiotropic cytokine, in primary cultured human airway smooth muscle cells. Levels of IL-6 protein and mRNA were significantly increased by endothelin-1 in dose- and time-dependent manners. Endothelin-1-induced IL-6 production was markedly attenuated by EGTA and various Ca(2+) channel inhibitors such as 3,5-bis(trifluoromethyl)-1H-pyrazole derivative (BTP-2), 1-[beta-[3-(4-methoxyphenyl)propoxy]-4-methoxyphenethyl]-1H-imidazole hydrochloride (SKF96365), and nifedipine. Endothelin-1-induced increases in intracellular Ca(2+) concentrations were significantly inhibited in Ca(2+)-free solution and by BTP-2, SKF96365, and nifedipine. The IL-6 synthesis was also inhibited by the extracellular signal-regulated kinase (ERK)1/2 inhibitor 1,4-diamino-2,3-dicyano-1,4-bis(o-aminophenylmercapto)-butadiene ethanolate (U0126) and the p38 inhibitor 4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)1H-imidazole (SB203580), but not by the c-Jun NH2-terminal kinase inhibitor anthra[1,9-cd]-pyrazol-6-(2H)-one (SP600125). Endothelin-1 significantly upregulated phosphorylation of ERK1/2 and p38 but blocking Ca(2+) influx pathways did not inhibit either upregulation. These findings demonstrate that endothelin-1-induced IL-6 synthesis in airway smooth muscle cells occurs via two parallel but independent events that include Ca(2+) influx and activation of ERK1/2 and p38.
authors.affiliation: Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Iwata
authors.forename: Satoru
authors.initials: S
authors.lastname: Ito
authors.forename: Mai
authors.initials: M
authors.lastname: Iwaki
authors.forename: Masashi
authors.initials: M
authors.lastname: Kondo
authors.forename: Toyokazu
authors.initials: T
authors.lastname: Sashio
authors.forename: Naoya
authors.initials: N
authors.lastname: Takeda
authors.forename: Masahiro
authors.initials: M
authors.lastname: Sokabe
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Hasegawa
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kume
mesh_terms: D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D019332:Endothelin-1 / Q000008:administration & dosage / Q000378:metabolism*; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D010766:Phosphorylation; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction; D013997:Time Factors; D015854:Up-Regulation; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D019332:Endothelin-1; D015850:Interleukin-6; D012333:RNA, Messenger; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048051:p38 Mitogen-Activated Protein Kinases; D002118:Calcium