title: Antioxidant defences and homeostasis of reactive oxygen species in different human mitochondrial DNA-depleted cell lines.
abstract: Three pairs of parental (rho+) and established mitochondrial DNA depleted (rho0) cells, derived from bone, lung and muscle were used to verify the influence of the nuclear background and the lack of efficient mitochondrial respiratory chain on antioxidant defences and homeostasis of intracellular reactive oxygen species (ROS). Mitochondrial DNA depletion significantly lowered glutathione reductase activity, glutathione (GSH) content, and consistently altered the GSH2 : oxidized glutathione ratio in all of the rho0 cell lines, albeit to differing extents, indicating the most oxidized redox state in bone rho0 cells. Activity, as well as gene expression and protein content, of superoxide dismutase showed a decrease in bone and muscle rho0 cell lines but not in lung rho0 cells. GSH peroxidase activity was four times higher in all three rho0 cell lines in comparison to the parental rho+, suggesting that this may be a necessary adaptation for survival without a functional respiratory chain. Taken together, these data suggest that the lack of respiratory chain prompts the cells to reduce their need for antioxidant defences in a tissue-specific manner, exposing them to a major risk of oxidative injury. In fact bone-derived rho0 cells displayed the highest steady-state level of intracellular ROS (measured directly by 2',7'-dichlorofluorescin, or indirectly by aconitase activity) compared to all the other rho+ and rho0 cells, both in the presence or absence of glucose. Analysis of mitochondrial and cytosolic/iron regulatory protein-1 aconitase indicated that most ROS of bone rho0 cells originate from sources other than mitochondria.
authors.affiliation: Dipartimento di Scienze Neurologiche, Universita di Padova, Padova, Italy. lodovica.vergani@unipd.it
authors.forename: Lodovica
authors.initials: L
authors.lastname: Vergani
authors.forename: Maura
authors.initials: M
authors.lastname: Floreani
authors.forename: Aaron
authors.initials: A
authors.lastname: Russell
authors.forename: Mara
authors.initials: M
authors.lastname: Ceccon
authors.forename: Eleonora
authors.initials: E
authors.lastname: Napoli
authors.forename: Anna
authors.initials: A
authors.lastname: Cabrelle
authors.forename: Lucia
authors.initials: L
authors.lastname: Valente
authors.forename: Federica
authors.initials: F
authors.lastname: Bragantini
authors.forename: Bertrand
authors.initials: B
authors.lastname: Leger
authors.forename: Federica
authors.initials: F
authors.lastname: Dabbeni-Sala
mesh_terms: D000154:Aconitate Hydratase / Q000032:analysis / Q000378:metabolism; D000975:Antioxidants / Q000378:metabolism*; D015153:Blotting, Western; D002277:Carcinoma / Q000378:metabolism; D002374:Catalase / Q000032:analysis / Q000378:metabolism; D045744:Cell Line, Tumor; D004272:DNA, Mitochondrial / Q000378:metabolism*; D005978:Glutathione / Q000032:analysis / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000032:analysis / Q000378:metabolism; D005980:Glutathione Reductase / Q000032:analysis / Q000378:metabolism; D005982:Glutathione Transferase / Q000032:analysis / Q000378:metabolism; D006706:Homeostasis; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism; D012516:Osteosarcoma / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012208:Rhabdomyosarcoma / Q000378:metabolism; D013347:Subcellular Fractions / Q000201:enzymology; D013482:Superoxide Dismutase / Q000032:analysis / Q000378:metabolism
chemical_list: D000975:Antioxidants; D004272:DNA, Mitochondrial; D017382:Reactive Oxygen Species; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D005980:Glutathione Reductase; D005982:Glutathione Transferase; D000154:Aconitate Hydratase; D005978:Glutathione