title: RTP801 Amplifies Nicotinamide Adenine Dinucleotide Phosphate Oxidase-4-Dependent Oxidative Stress Induced by Cigarette Smoke.
abstract: Tobacco smoke (TS) causes chronic obstructive pulmonary disease, including chronic bronchitis, emphysema, and asthma. Rtp801, an inhibitor of mechanistic target of rapamycin, is induced by oxidative stress triggered by TS. Its up-regulation drives lung susceptibility to TS injury by enhancing inflammation and alveolar destruction. We postulated that Rtp801 is not only increased by reactive oxygen species (ROS) in TS but also instrumental in creating a feedforward process leading to amplification of endogenous ROS generation. We used cigarette smoke extract (CSE) to model the effect of TS in wild-type (Wt) and knockout (KO-Rtp801) mouse lung fibroblasts (MLF). The production of superoxide anion in KO-Rtp801 MLF was lower than that in Rtp801 Wt cells after CSE treatment, and it was inhibited in Wt MLF by silencing nicotinamide adenine dinucleotide phosphate oxidase-4 (Nox4) expression with small interfering Nox4 RNA. We observed a cytoplasmic location of ROS formation by real-time redox changes using reduction-oxidation-sensitive green fluorescent protein profluorescent probes. Both the superoxide production and the increase in the cytoplasmic redox were inhibited by apocynin. Reduction in the activity of Sod and decreases in the expression of Sod2 and Gpx1 genes were associated with Rtp801 CSE induction. The ROS produced by Nox4 in conjunction with the decrease in cellular antioxidant enzymatic defenses may account for the observed cytoplasmic redox changes and cellular damage caused by TS.
authors.affiliation: 1 Program in Translational Lung Research, Division of Pulmonary Sciences and Critical Care Medicine.|2 Cardiovascular Pulmonary Research Laboratories, Department of Pediatrics, and.
authors.forename: Daniel
authors.initials: D
authors.lastname: Hernández-Saavedra
authors.affiliation: 1 Program in Translational Lung Research, Division of Pulmonary Sciences and Critical Care Medicine.
authors.forename: Linda
authors.initials: L
authors.lastname: Sanders
authors.affiliation: 1 Program in Translational Lung Research, Division of Pulmonary Sciences and Critical Care Medicine.
authors.forename: Mario J
authors.initials: MJ
authors.lastname: Perez
authors.affiliation: 3 Department of Medicine, National Jewish Health, Denver, Colorado; and.
authors.forename: Beata
authors.initials: B
authors.lastname: Kosmider
authors.affiliation: 1 Program in Translational Lung Research, Division of Pulmonary Sciences and Critical Care Medicine.
authors.forename: Lynelle P
authors.initials: LP
authors.lastname: Smith
authors.affiliation: 4 Department of Surgery, Division of Cardiothoracic Surgery, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, Colorado.
authors.forename: John D
authors.initials: JD
authors.lastname: Mitchell
authors.affiliation: 5 Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, Tokyo, Japan.
authors.forename: Toshinori
authors.initials: T
authors.lastname: Yoshida
authors.affiliation: 1 Program in Translational Lung Research, Division of Pulmonary Sciences and Critical Care Medicine.
authors.forename: Rubin M
authors.initials: RM
authors.lastname: Tuder
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D002470:Cell Survival; D003593:Cytoplasm / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005347:Fibroblasts / Q000378:metabolism; D005456:Fluorescent Dyes / Q000378:metabolism; D005786:Gene Expression Regulation; D019803:Glutathione Disulfide / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008168:Lung / Q000166:cytology; D018345:Mice, Knockout; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases / Q000378:metabolism*; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D012907:Smoking / Q000009:adverse effects*; D013481:Superoxides / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000975:Antioxidants; C469991:DDIT4 protein, human; D004268:DNA-Binding Proteins; C450979:Ddit4l protein, mouse; D005456:Fluorescent Dyes; D014157:Transcription Factors; D013481:Superoxides; D049452:Green Fluorescent Proteins; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases; C422943:Nox4 protein, mouse; D019803:Glutathione Disulfide
keywords: Rtp801 cigarette smoke extract induction; nicotinamide adenine dinucleotide phosphate oxidase-4; oxidative stress