title: Cigarette smoke-induced oxidative stress suppresses generation of dendritic cell IL-12 and IL-23 through ERK-dependent pathways.
abstract: IL-12p70, a heterodimer composed of p35 and p40 subunits, is a key polarizing cytokine produced by maturing dendritic cells (DCs). We report that cigarette smoke extract (CSE), an extract of soluble cigarette smoke components, suppresses both p35 and p40 production by LPS or CD40L-matured DCs. Suppression of IL-12p70 production from maturing DCs was not observed in the presence of nicotine concentrations achievable in CSE or in the circulation of smokers. The suppressed IL-12p70 protein production by CSE-conditioned DCs was restored by pretreatment of DCs or CSE with the antioxidants N-acetylcysteine and catalase. Inhibition of DC IL-12p70 by CSE required activation of ERK-dependent pathways, since inhibition of ERK abrogated the suppressive effect of CSE on IL-12 secretion. Oxidative stress and sustained ERK phosphorylation by CSE enhanced nuclear levels of the p40 transcriptional repressor c-fos in both immature and maturing DCs. Suppression of the p40 subunit by CSE also resulted in diminished production of IL-23 protein by maturing DCs. Using a murine model of chronic cigarette smoke exposure, we observed that systemic and lung DCs from mice "smokers" produced significantly less IL-12p70 and p40 protein upon maturation. This inhibitory effect was selective, since production of TNF-alpha during DC maturation was enhanced in the smokers. These data imply that oxidative stress generated by cigarette smoke exposure suppresses the generation of key cytokines by maturing DCs through the activation of ERK-dependent pathways. Some of the cigarette smoke-induced inhibitory effects on DC function may be mitigated by antioxidants.
authors.affiliation: Department of Internal Medicine, Thoracic Diseases Research Unit, Division of Pulmonary Critical Care, Mayo Clinic and Foundation, Rochester, MN 55905, USA.
authors.forename: Paula R
authors.initials: PR
authors.lastname: Kroening
authors.forename: Terrance W
authors.initials: TW
authors.lastname: Barnes
authors.forename: Larry
authors.initials: L
authors.lastname: Pease
authors.forename: Andrew
authors.initials: A
authors.lastname: Limper
authors.forename: Hirohito
authors.initials: H
authors.lastname: Kita
authors.forename: Robert
authors.initials: R
authors.lastname: Vassallo
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D006801:Humans; D018664:Interleukin-12 / Q000032:analysis / Q000276:immunology*; D053759:Interleukin-23 / Q000032:analysis / Q000276:immunology*; D051379:Mice; D009538:Nicotine / Q000032:analysis; D018384:Oxidative Stress; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D012907:Smoking / Q000009:adverse effects / Q000276:immunology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D000975:Antioxidants; D053759:Interleukin-23; D016760:Proto-Oncogene Proteins c-fos; D018664:Interleukin-12; D009538:Nicotine; D048049:Extracellular Signal-Regulated MAP Kinases; D048051:p38 Mitogen-Activated Protein Kinases