title: Proteomic analysis of oxidative stress-responsive proteins in human pneumocytes: insight into the regulation of DJ-1 expression.
abstract: Oxidative injury is believed to play an important role in the pathogenesis of lung diseases such as emphysema and lung cancer. We examined the effects of a classic reactive oxygen species, H 2O 2, on the hydrogen peroxide response proteins (HPRP) in human pneumocytes using comparative two-dimensional gel electrophoresis (2DE) and peptide mass fingerprinting. Four HPRP-associated proteins (DJ-1, peroxiredoxins [Prxs] I and IV and glyceraldehyde-3-phosphate dehydrogenase [GAPDH]) were changed upon exposure to H 2O 2 (1 mM for 24 h). H 2O 2 exposure increased the acid (oxidized) form and decreased the basic (reduced) form of DJ-1 (pI 5.8 and 6.2, respectively), Prx I and IV and GAPDH. Mechanistic studies on DJ-1 indicated that the slow recovery of the reduced form was blocked by cyclohexamide, suggesting that the recovery was due to new protein synthesis. Total DJ-1 expression was decreased by increasing concentrations of H 2O 2. In contrast, a more complex mix of oxidants in the form of cigarette smoke extract (CSE) dose-dependently increased DJ-1 expression and produced a novel DJ-1 isoform (p I 5.6). Moreover, DJ-1 expression was higher in the lungs of chronic cigarette smokers compared with nonsmokers, a result which resembled the effects of CSE in cultured cells. These data indicate that in human pneumocytes, DJ-1 functions as an antioxidant but that no enzymatic system converts the oxidized to the reduced form. Up-regulation of DJ-1 by cigarette smoke may be a compensatory mechanism that protects the lung from oxidative stress-related injury.
authors.affiliation: Department of Biochemistry and Department of Medicine, Division of Pulmonary Critical Care and Pulmonary Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA.
authors.forename: Xunbao
authors.initials: X
authors.lastname: Duan
authors.forename: Steven G
authors.initials: SG
authors.lastname: Kelsen
authors.forename: Salim
authors.initials: S
authors.lastname: Merali
mesh_terms: D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D015513:Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D016877:Oxidants / Q000378:metabolism / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D000071617:Protein Deglycase DJ-1; D020543:Proteome / Q000032:analysis*; D040901:Proteomics / Q000379:methods; D011650:Pulmonary Alveoli / Q000166:cytology / Q000378:metabolism*
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D015513:Oncogene Proteins; D016877:Oxidants; D020543:Proteome; D006861:Hydrogen Peroxide; C105131:PARK7 protein, human; D000071617:Protein Deglycase DJ-1