Cigarette smoking blocks the protective expression of Nrf2/ARE pathway in peripheral mononuclear cells of young heavy smokers favouring inflammation

• Published in: PloS one Vol. 4; no. 12; p. e8225
• Main Authors: Garbin, Ulisse, Fratta Pasini, Anna, Stranieri, Chiara, Cominacini, Mattia, Pasini, Andrea, Manfro, Stefania, Lugoboni, Fabio, Mozzini, Chiara, Guidi, GianCesare, Faccini, Giovanni, Cominacini, Luciano
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 09.12.2009; Public Library of Science (PLoS)
• Subjects: Adolescent; Adult; Alcohol; Antioxidants; Antioxidants (Nutrients); Antioxidants - metabolism; Arteriosclerosis; Atherosclerosis; Biomarkers - metabolism; Blood; Blood cells; Blood Donors; Blood lipids; C-reactive protein; Cardiovascular disease; Cardiovascular Disorders/Coronary Artery Disease; Cardiovascular Disorders/Vascular Biology; Cell Biology/Leukocyte Signaling and Gene Expression; Chronic obstructive pulmonary disease; Cigarette smoke; Cigarette smoking; Cigarettes; Cytokines; Cytoprotection; Enzyme Activation; Exercise; Female; Gene expression; Genes; Glutamate-Cysteine Ligase - metabolism; Glutathione - metabolism; Heme Oxygenase-1 - metabolism; Humans; I-kappa B Proteins - metabolism; Inflammation; Inflammation - enzymology; Inflammation - pathology; Interleukin-6 - metabolism; Internal medicine; Leukocytes (mononuclear); Leukocytes, Mononuclear - enzymology; Leukocytes, Mononuclear - pathology; Lung diseases; Lungs; Male; Medicine; Membrane lipids; Microscopy; Morphology; NAD(P)H oxidase; NADPH Oxidases - metabolism; NF-E2-Related Factor 2 - metabolism; NF-kappa B - metabolism; NF-KappaB Inhibitor alpha; NF-κB protein; Oxidase; Oxidases; Oxidation; Oxidative stress; Oxygen; Peripheral blood mononuclear cells; Phosphatidylcholines - blood; Phospholipids; Public Health and Epidemiology/Social and Behavioral Determinants of Health; Reactive oxygen species; Reactive Oxygen Species - metabolism; Regulation; Response Elements - genetics; Ribonucleic acid; Risk factors; RNA; RNA-mediated interference; Sepsis; siRNA; Smoke; Smokers; Smoking; Smoking - adverse effects; Smoking - blood; Transcription activation; Transcription factors; Vitamin C; Young Adult; Youth smoking
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0008225

Cigarette smoking is an important risk factor for atherosclerosis, a chronic inflammatory disease. However the underlying factors of this effect are unclear. It has been hypothesized that water-soluble components of cigarette smoke can directly promote oxidative stress in vasculature and blood cells. Aim of this study was to study the relationship between oxidative stress and inflammation in a group of young smokers. To do this we evaluated: 1) the oxidation products of phospholipids (oxPAPC) in peripheral blood mononuclear cells (PBMC); 2) their role in causing PBMC reactive oxygen species (ROS) generation and changes in GSH; 3) the expression of the transcription factor NF-E2-related factor 2 (Nrf2) and of related antioxidant genes (ARE); 4) the activation of NF-kB and C-reactive protein (CRP) values. We studied 90 healthy volunteers: 32 non-smokers, 32 moderate smokers (5-10 cigarettes/day) and 26 heavy smokers (25-40 cigarettes/day). OxPAPC and p47phox expression, that reasonably reflects NADPH oxidase activity, were higher in moderate smokers and heavy smokers than in non-smokers (p<0.01), the highest values being in heavy smokers (p<0.01). In in vitro studies oxPAPC increased ROS generation via NADPH oxidase activation. GSH in PBMC and plasma was lower in moderate smokers and heavy smokers than in non-smokers (p<0.01), the lowest values being in heavy smokers (p<0.01). Nrf2 expression in PBMC was higher in moderate smokers than in non-smokers (p<0.01), but not in heavy smokers, who had the highest levels of NF-kB and CRP (p<0.01). In in vitro studies oxPAPC dose-dependently increased NF-kB activation, whereas at the highest concentrations Nrf2 expression was repressed. The small interference (si) RNA-mediated knockdown of NF-kappaB/p65 increased about three times the expression of Nrf2 stimulated with oxPAPC. Cigarette smoke promotes oxPAPC formation and oxidative stress in PBMC. This may cause the activation of NF-kB that in turn may participate in the negative regulation of Nrf2/ARE pathway favouring inflammation.