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Coenzyme Q and the regulation of intracellular steady‐state levels of superoxide in HL‐60 cells
Author(s) -
GonzálezAragón David,
Burón María I.,
LópezLluch Guillermo,
Hermán María D.,
GómezDíaz Consuelo,
Navas PlÁCido,
Villalba José M.
Publication year - 2005
Publication title -
biofactors
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.204
H-Index - 94
eISSN - 1872-8081
pISSN - 0951-6433
DOI - 10.1002/biof.5520250105
Subject(s) - superoxide , coenzyme q – cytochrome c reductase , intracellular , chemistry , mitochondrion , biochemistry , coenzyme q10 , viability assay , microbiology and biotechnology , cell , biology , enzyme , cytochrome c
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.