title: Specificity of coenzyme Q10 for a balanced function of respiratory chain and endogenous ubiquinone biosynthesis in human cells.
abstract: Coenzyme Q (Q) is an obligatory component of both respiratory chain and uncoupling proteins. Also, Q acts as an antioxidant in cellular membranes. Several neurodegenerative diseases are associated with modifications of Q10 levels. For these reasons, therapies based on Q supplementation in the diet are currently studied in order to mitigate the symptoms of these diseases. However, the incorporation of exogenous Q also affects aging process in nematodes probably affecting reactive oxygen species (ROS) production. The aim of the present work is to clarify if supplementation with both Q10 and Q6 isoforms affects mitochondrial Q10 content, respiratory chain activity and ROS levels in human cells. Cells incorporated exogenously added Q10 and Q6 isoforms into mitochondria that produced changes in mitochondrial activity depending on the side chain length. Supplementation with Q10, but not with Q6, increased mitochondrial Q-dependent activities. However, Q6 affected the mitochondrial membrane potential, ROS production, and increased the protein levels of both catalase and Mn-superoxide dismutase (Mn-SOD). Also, Q6 induced a transient decrease in endogenous mitochondrial Q10 levels by increasing its catabolism. These results show that human cells supplemented with Q6 undergo a mitochondrial impairment, which is not observed with Q10 supplementation.
authors.affiliation: Centro Andaluz de Biología del Desarrollo (CABD), Universidad Pablo de Olavide, Carretera de Utrera Km 1, 43013, Sevilla, Spain.
authors.forename: Daniel J M
authors.initials: DJ
authors.lastname: Fernández-Ayala
authors.forename: Guillermo
authors.initials: G
authors.lastname: López-Lluch
authors.forename: Macarena
authors.initials: M
authors.lastname: García-Valdés
authors.forename: Antonio
authors.initials: A
authors.lastname: Arroyo
authors.forename: Plácido
authors.initials: P
authors.lastname: Navas
mesh_terms: D002458:Cell Fractionation; D003067:Coenzymes; D004579:Electron Transport / Q000187:drug effects / Q000502:physiology; D005434:Flow Cytometry; D005453:Fluorescence; D018922:HL-60 Cells; D006801:Humans; D007527:Isoenzymes; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013379:Substrate Specificity; D014451:Ubiquinone / Q000031:analogs & derivatives* / Q000096:biosynthesis* / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D003067:Coenzymes; D007527:Isoenzymes; D017382:Reactive Oxygen Species; C032165:ubiquinone 6; D014451:Ubiquinone; C024989:coenzyme Q10