title: Coenzyme Q and the regulation of intracellular steady-state levels of superoxide in HL-60 cells.
abstract: The present work was set to study how CoQ concentrations affected steady-state levels of superoxide in a cellular model of partial CoQ(10) deficiency in cultured human myeloid leukemia HL-60 cells. Culturing HL-60 cells in the presence of p-aminobenzoate, a competitive inhibitor of polyprenyl-4-hydroxybenzoate transferase (Coq2p), produced a significant decrease of CoQ(10) levels without affecting cell viability. Concomitant decreases in CoQ-dependent electron transport activity and mitochondrial membrane potential were observed under these conditions. Intracellular superoxide was significantly elevated in cells treated with p-aminobenzoate, both under serum-containing and serum-free conditions, and this effect was reversed by exogenous CoQ(10). A slight increase of superoxide was also observed in CoQ(10)-supplemented cells in the absence of serum. Our results support a requirement for CoQ(10) to control superoxide levels in HL-60 cells. The importance of extramitochondrial sources of superoxide in cells with impaired CoQ(10) biosynthesis is discussed.
authors.affiliation: Departamento de Biología Celular, Fisiología e Inmunología, Universidad de Córdoba, Spain.
authors.forename: David
authors.initials: D
authors.lastname: González-Aragón
authors.forename: María I
authors.initials: MI
authors.lastname: Burón
authors.forename: Guillermo
authors.initials: G
authors.lastname: López-Lluch
authors.forename: María D
authors.initials: MD
authors.lastname: Hermán
authors.forename: Consuelo
authors.initials: C
authors.lastname: Gómez-Díaz
authors.forename: Plácido
authors.initials: P
authors.lastname: Navas
authors.forename: José M
authors.initials: JM
authors.lastname: Villalba
mesh_terms: D010129:4-Aminobenzoic Acid / Q000494:pharmacology; D019883:Alkyl and Aryl Transferases / Q000037:antagonists & inhibitors*; D003067:Coenzymes; D018922:HL-60 Cells; D006801:Humans; D010617:Phenanthridines / Q000378:metabolism; D013384:Succinate Cytochrome c Oxidoreductase / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism*; D014451:Ubiquinone / Q000031:analogs & derivatives* / Q000172:deficiency / Q000502:physiology
chemical_list: D003067:Coenzymes; D010617:Phenanthridines; D013481:Superoxides; D014451:Ubiquinone; C058428:hydroethidine; D013384:Succinate Cytochrome c Oxidoreductase; D019883:Alkyl and Aryl Transferases; C021386:4-hydroxybenzoate polyprenyltransferase; C024989:coenzyme Q10; D010129:4-Aminobenzoic Acid