title: Nicotine mediates oxidative stress and apoptosis through cross talk between NOX1 and Bcl-2 in lung epithelial cells.
abstract: Nicotine contributes to the onset and progression of several pulmonary diseases. Among the various pathophysiological mechanisms triggered by nicotine, oxidative stress and cell death are reported in several cell types. We found that chronic exposure to nicotine (48h) induced NOX1-dependent oxidative stress and apoptosis in primary pulmonary cells. In murine (MLE-12) and human (BEAS-2B) lung epithelial cell lines, nicotine acted as a sensitizer to cell death and synergistically enhanced apoptosis when cells were concomitantly exposed to hyperoxia. The precise signaling pathway was investigated in MLE-12 cells in which NOX1 was abrogated by a specific inhibitor or stably silenced by shRNA. In the early phase of exposure (1h), nicotine mediated intracellular Ca(2+) fluxes and activation of protein kinase C, which in its turn activated NOX1, leading to cellular and mitochondrial oxidative stress. The latter triggered the intrinsic apoptotic machinery by modulating the expression of Bcl-2 and Bax. Overexpression of Bcl-2 completely prevented nicotine's detrimental effects, suggesting Bcl-2as a downstream key regulator in nicotine/NOX1-induced cell damage. These results suggest that NOX1 is a major contributor to the generation of intracellular oxidative stress induced by nicotine and might be an important molecule to target in nicotine-related lung pathologies.
authors.affiliation: Department of Pediatrics, Children's Hospital, 1211 Geneva, Switzerland; Department of Pathology and Immunology, Medical School, and University of Geneva, Geneva, Switzerland.
authors.forename: Filippo
authors.initials: F
authors.lastname: Zanetti
authors.affiliation: Venetian Institute of Molecular Medicine, University of Padova, Padova, Italy.
authors.forename: Marta
authors.initials: M
authors.lastname: Giacomello
authors.affiliation: Department of Pediatrics, Children's Hospital, 1211 Geneva, Switzerland; Department of Pathology and Immunology, Medical School, and University of Geneva, Geneva, Switzerland.
authors.forename: Yves
authors.initials: Y
authors.lastname: Donati
authors.affiliation: Department of Pediatrics, Children's Hospital, 1211 Geneva, Switzerland; Department of Pathology and Immunology, Medical School, and University of Geneva, Geneva, Switzerland.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Carnesecchi
authors.affiliation: Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland.
authors.forename: Maud
authors.initials: M
authors.lastname: Frieden
authors.affiliation: Department of Pediatrics, Children's Hospital, 1211 Geneva, Switzerland; Department of Pathology and Immunology, Medical School, and University of Geneva, Geneva, Switzerland. Electronic address: Constance.Barazzone@hcuge.ch.
authors.forename: Constance
authors.initials: C
authors.lastname: Barazzone-Argiroffo
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D008168:Lung / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D009247:NADH, NADPH Oxidoreductases / Q000037:antagonists & inhibitors / Q000502:physiology*; D000074624:NADPH Oxidase 1; D009538:Nicotine / Q000494:pharmacology*; D018722:Nicotinic Agonists / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D018722:Nicotinic Agonists; D019253:Proto-Oncogene Proteins c-bcl-2; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D009538:Nicotine; D009247:NADH, NADPH Oxidoreductases; D000074624:NADPH Oxidase 1; C000614711:NOX1 protein, mouse; D002118:Calcium
keywords: Alveolar epithelial type II cells; Apoptosis; Bcl-2; Free radicals; NOX1; Nicotine; Oxidative stress