title: Mitochondrial localization of catalase provides optimal protection from H2O2-induced cell death in lung epithelial cells.
abstract: Reactive oxygen species (ROS) can cause cell injury and death via mitochondrial-dependent pathways, and supplementation with antioxidants has been shown to ameliorate these processes. The c-Jun NH(2)-terminal kinase (JNK) pathway has been shown to play a critical role in ROS-induced cell death. To determine if targeting catalase (CAT) to the mitochondria provides better protection than cytosolic expression against H(2)O(2)-induced injury, the following two approaches were taken: 1) adenoviral-mediated transduction was performed using cytosolic (CCAT) or mitochondrial (MCAT) CAT cDNAs and 2) stable cell lines were generated overexpressing CAT in mitochondria (n = 3). Cells were exposed to 250 microM H(2)O(2), and cell survival, mitochondrial function, cytochrome c release, and JNK activity were analyzed. Although all viral transduced cells had a transient twofold increase in CAT activity, MCAT cells had significantly higher survival rates, the best mitochondrial function, and lowest JNK activity compared with CCAT and LacZ controls. The improved protection with MCAT was observed in primary type II lung epithelial cells and in transformed lung epithelial cells. In the three stable cell lines, cell survival directly correlated with extent of mitochondrial localization (r = 0.60572, P < 0.05) and not overall CAT activity (r = -0.45501, P < 0.05). Data indicate that targeting of antioxidants directly to the mitochondria is more effective in protecting lung epithelial cells against ROS-induced injury. This has important implications in antioxidant supplementation trials to prevent ROS-induced lung injury in critically ill patients.
authors.affiliation: Department of Pediatrics, CardioPulmonary Research Institute, Winthrop University Hospital, SUNY Stony Brook School of Medicine, Suite 505, 222 Station Plaza North, Mineola, NY 11501, USA.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Arita
authors.forename: S Hella
authors.initials: SH
authors.lastname: Harkness
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Kazzaz
authors.forename: Hshi-chi
authors.initials: HC
authors.lastname: Koo
authors.forename: Ansamma
authors.initials: A
authors.lastname: Joseph
authors.forename: J Andres
authors.initials: JA
authors.lastname: Melendez
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Davis
authors.forename: A
authors.initials: A
authors.lastname: Chander
authors.forename: Yuchi
authors.initials: Y
authors.lastname: Li
mesh_terms: D000818:Animals; D002374:Catalase / Q000235:genetics / Q000378:metabolism*; D016923:Cell Death / Q000187:drug effects*; D003600:Cytosol / Q000201:enzymology; D005822:Genetic Vectors; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity*; D008168:Lung / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology; D008297:Male; D008928:Mitochondria / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000378:metabolism; D020545:Respiratory Mucosa / Q000187:drug effects / Q000201:enzymology* / Q000473:pathology
chemical_list: D011994:Recombinant Proteins; D006861:Hydrogen Peroxide; D002374:Catalase