title: Impaired nuclear factor erythroid 2-related factor 2 expression increases apoptosis of airway epithelial cells in patients with chronic obstructive pulmonary disease due to cigarette smoking.
abstract: BACKGROUND
  Cigarette smoking-induced oxidative stress is known to be a key mechanism in COPD pathogenesis. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a central transcription factor that regulates the antioxidant defense system. The aim of this study was to compare Nrf2 expression in COPD subjects and control subjects, and to determine the role of Nrf2 in protecting against oxidative stress-induced apoptosis.
  
  
  METHODS
  We enrolled 8 COPD subjects and 7 control subjects in this study. We performed bronchial brushing by bronchoscopy and obtained bronchial epithelial cells from the airways. Nrf2 expression in bronchial epithelial cells was evaluated by real-time PCR and Western blotting. We examined the effect of 10 or 15 % cigarette smoke extract (CSE) induced A549 cells apoptosis using a time-lapse cell imaging assay with caspase-3/7 activation detecting reagent and performed Terminal deoxynucleotidyltransferase-mediated dUTP nick end labelling assay for confirming A549 cells apoptosis. We also examined the effects of Nrf2 knockdown and, 0.1, 0.5, and 1.0 mM N-acetyl cysteine on CSE-induced apoptosis. Statistical analyses were performed using t-test, paired t-test or an analysis of variance followed by the Tukey-Kramer method.
  
  
  RESULTS
  Nrf2 mRNA expression in COPD subjects was significantly lower than that in control subjects and Nrf2 mRNA were negatively correlated with pack year. Nrf2 protein in COPD subjects was significantly lower than that in control subjects. CSE-induced A549 cells apoptosis was increased in a time-, concentration-dependent manner, and was significantly increased by Nrf2 knockdown. N-acetyl cysteine significantly ameliorated CSE-induced apoptosis.
  
  
  CONCLUSIONS
  Nrf2 expression was lower in COPD patients than in control subjects. Nrf2 might have a protective role against apoptosis caused by CSE-induced oxidative stress. These results suggest an involvement of Nrf2 in COPD and administration of antioxidants to patients with COPD might be a basic therapeutic option.
authors: Department of Respiratory Medicine, Graduate School of Medicine, Osaka City University, 1-4-3, Asahi-machi, Abeno-ku, Osaka, 545-8585, Japan. kazuhironishiyamato@gmail.com.
authors: Kazuhiro
authors: K
authors: Yamada
authors: Department of Respiratory Medicine, Graduate School of Medicine, Osaka City University, 1-4-3, Asahi-machi, Abeno-ku, Osaka, 545-8585, Japan. kazuasai@med.osaka-cu.ac.jp.
authors: Kazuhisa
authors: K
authors: Asai
authors: Department of Respiratory Medicine, Graduate School of Medicine, Osaka City University, 1-4-3, Asahi-machi, Abeno-ku, Osaka, 545-8585, Japan. chouan.com@gmail.com.
authors: Fumihiro
authors: F
authors: Nagayasu
authors: Department of Respiratory Medicine, Graduate School of Medicine, Osaka City University, 1-4-3, Asahi-machi, Abeno-ku, Osaka, 545-8585, Japan. m1162967@med.osaka-cu.ac.jp.
authors: Kanako
authors: K
authors: Sato
authors: Department of Respiratory Medicine, Graduate School of Medicine, Osaka City University, 1-4-3, Asahi-machi, Abeno-ku, Osaka, 545-8585, Japan. naru_hodou@yahoo.co.jp.
authors: Naoki
authors: N
authors: Ijiri
authors: Department of Respiratory Medicine, Graduate School of Medicine, Osaka City University, 1-4-3, Asahi-machi, Abeno-ku, Osaka, 545-8585, Japan. yoshiinao@med.osaka-cu.ac.jp.
authors: Naoko
authors: N
authors: Yoshii
authors: Department of Respiratory Medicine, Graduate School of Medicine, Osaka City University, 1-4-3, Asahi-machi, Abeno-ku, Osaka, 545-8585, Japan. yumiko1234@gmail.com.
authors: Yumiko
authors: Y
authors: Imahashi
authors: Department of Respiratory Medicine, Graduate School of Medicine, Osaka City University, 1-4-3, Asahi-machi, Abeno-ku, Osaka, 545-8585, Japan. tetsuyaw5353@gmail.com.
authors: Tetsuya
authors: T
authors: Watanabe
authors: Department of Respiratory Medicine, Graduate School of Medicine, Osaka City University, 1-4-3, Asahi-machi, Abeno-ku, Osaka, 545-8585, Japan. m1152721@med.osaka-cu.ac.jp.
authors: Yoshihiro
authors: Y
authors: Tochino
authors: Department of Respiratory Medicine, Graduate School of Medicine, Osaka City University, 1-4-3, Asahi-machi, Abeno-ku, Osaka, 545-8585, Japan. kanazawa-h@med.osaka-cu.ac.jp.
authors: Hiroshi
authors: H
authors: Kanazawa
authors: Department of Respiratory Medicine, Graduate School of Medicine, Osaka City University, 1-4-3, Asahi-machi, Abeno-ku, Osaka, 545-8585, Japan. kazutoh@msic.med.osaka-cu.ac.jp.
authors: Kazuto
authors: K
authors: Hirata
mesh_terms: D000368:Aged; D017209:Apoptosis / Q000235:genetics*; D015153:Blotting, Western; D001944:Breath Tests; D001980:Bronchi / Q000166:cytology / Q000378:metabolism; D016022:Case-Control Studies; D045744:Cell Line, Tumor; D004847:Epithelial Cells / Q000378:metabolism*; D005260:Female; D055785:Gene Knockdown Techniques; D006801:Humans; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D008297:Male; D008875:Middle Aged; D051267:NF-E2-Related Factor 2 / Q000235:genetics* / Q000378:metabolism; D018384:Oxidative Stress / Q000235:genetics*; D029424:Pulmonary Disease, Chronic Obstructive / Q000209:etiology / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D020545:Respiratory Mucosa / Q000166:cytology / Q000378:metabolism; D012906:Smoke / Q000009:adverse effects*; D012907:Smoking / Q000009:adverse effects / Q000235:genetics* / Q000378:metabolism; D059008:Time-Lapse Imaging; D014026:Nicotiana
chemical_list: D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human; D012333:RNA, Messenger; D012906:Smoke