Cigarette smoking blocks the protective expression of Nrf2/ARE pathway in peripheral mononuclear cells of young heavy smokers favouring inflammation.
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.
Garbin
Ulisse
U
Department of Biomedical and Surgical Sciences, Section of Internal Medicine, University of Verona, Verona, Italy.
Fratta Pasini
Anna
A
Stranieri
Chiara
C
Cominacini
Mattia
M
Pasini
Andrea
A
Manfro
Stefania
S
Lugoboni
Fabio
F
Mozzini
Chiara
C
Guidi
GianCesare
G
Faccini
Giovanni
G
Cominacini
Luciano
L
D000293:Adolescent; D000328:Adult; D000975:Antioxidants / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism; D001782:Blood Donors; D019610:Cytoprotection; D004789:Enzyme Activation; D005260:Female; D005721:Glutamate-Cysteine Ligase / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D051547:Heme Oxygenase-1 / Q000378:metabolism; D006801:Humans; D020672:I-kappa B Proteins / Q000378:metabolism; D007249:Inflammation / Q000201:enzymology / Q000473:pathology*; D015850:Interleukin-6 / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000201:enzymology / Q000473:pathology*; D008297:Male; D019255:NADPH Oxidases / Q000378:metabolism; D051267:NF-E2-Related Factor 2 / Q000378:metabolism*; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism; D010713:Phosphatidylcholines / Q000097:blood; D017382:Reactive Oxygen Species / Q000378:metabolism; D020218:Response Elements / Q000235:genetics*; D012907:Smoking / Q000009:adverse effects* / Q000097:blood; D055815:Young Adult
D000975:Antioxidants; D015415:Biomarkers; D020672:I-kappa B Proteins; D015850:Interleukin-6; D051267:NF-E2-Related Factor 2; D016328:NF-kappa B; C495635:NFE2L2 protein, human; C000606204:NFKBIA protein, human; D010713:Phosphatidylcholines; D017382:Reactive Oxygen Species; C472349:oxidized-L-alpha-1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine; D000072000:NF-KappaB Inhibitor alpha; D051547:Heme Oxygenase-1; D019255:NADPH Oxidases; D005721:Glutamate-Cysteine Ligase; D005978:Glutathione