ROS production in brown adipose tissue mitochondria: the question of UCP1-dependence.
Whether active UCP1 can reduce ROS production in brown-fat mitochondria is presently not settled. The issue is of principal significance, as it can be seen as a proof- or disproof-of-principle concerning the ability of any protein to diminish ROS production through membrane depolarization. We therefore undertook a comprehensive investigation of the significance of UCP1 for ROS production, by comparing the ROS production in brown-fat mitochondria isolated from wildtype mice (that display membrane depolarization) or from UCP1(-/-) mice (with a high membrane potential). We tested the significance of UCP1 for glycerol-3-phosphate-supported ROS production by three methods (fluorescent dihydroethidium and the ESR probe PHH for superoxide, and fluorescent Amplex Red for hydrogen peroxide), and followed ROS production also with succinate, acyl-CoA or pyruvate as substrate. We studied the effects of the reverse electron flow inhibitor rotenone, the UCP1 activity inhibitor GDP, and the uncoupler FCCP. We also examined the effect of a physiologically induced increase in UCP1 amount. We noted GDP effects that were not UCP1-related. We conclude that only ROS production supported by exogenously added succinate was affected by the presence of active UCP1; ROS production supported by any other tested substrate (including endogenously generated succinate) was unaffected. This conclusion indicates that UCP1 is not involved in control of ROS production in brown-fat mitochondria. Extrapolation of these data to other tissues would imply that membrane depolarization may not necessarily decrease physiologically relevant ROS production. This article is a part of a Special Issue entitled: 18th European Bioenergetics Conference (Biochim. Biophys. Acta, Volume 1837, Issue 7, July 2014).
Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, SE-106 91 Stockholm, Sweden.
Irina G
IG
Shabalina
Department of Bioenergetics, Institute of Physiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, CZ 142 20 Prague, Czech Republic.
Marek
M
Vrbacký
Department of Bioenergetics, Institute of Physiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, CZ 142 20 Prague, Czech Republic.
Alena
A
Pecinová
Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, SE-106 91 Stockholm, Sweden.
Anastasia V
AV
Kalinovich
Department of Bioenergetics, Institute of Physiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, CZ 142 20 Prague, Czech Republic.
Zdeněk
Z
Drahota
Department of Bioenergetics, Institute of Physiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, CZ 142 20 Prague, Czech Republic.
Josef
J
Houštěk
Department of Bioenergetics, Institute of Physiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, CZ 142 20 Prague, Czech Republic.
Tomáš
T
Mráček
Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, SE-106 91 Stockholm, Sweden. Electronic address: barbara.cannon@su.se.
Barbara
B
Cannon
Department of Molecular Biosciences, The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, SE-106 91 Stockholm, Sweden.
Jan
J
Nedergaard
D002001:Adipose Tissue, Brown / Q000378:metabolism*; D000818:Animals; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D003080:Cold Temperature; D004578:Electron Spin Resonance Spectroscopy; D005994:Glycerophosphates / Q000494:pharmacology; D006153:Guanosine Diphosphate / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000378:metabolism; D015151:Immunoblotting; D007473:Ion Channels / Q000235:genetics / Q000378:metabolism*; D008297:Male; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D010101:Oxygen Consumption / Q000187:drug effects; D061209:Proton Ionophores / Q000494:pharmacology; D019289:Pyruvic Acid / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism*; D019802:Succinic Acid / Q000494:pharmacology; D013481:Superoxides / Q000378:metabolism; D000071256:Uncoupling Protein 1
D005994:Glycerophosphates; D007473:Ion Channels; D024101:Mitochondrial Proteins; D061209:Proton Ionophores; D017382:Reactive Oxygen Species; C000604372:Ucp1 protein, mouse; D000071256:Uncoupling Protein 1; D013481:Superoxides; D006153:Guanosine Diphosphate; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; D019289:Pyruvic Acid; C029620:alpha-glycerophosphoric acid; D019802:Succinic Acid; D006861:Hydrogen Peroxide
Brown adipose tissue mitochondria; Cold acclimation; Glycerol-3-phosphate dehydrogenase; Reactive oxygen species; Succinate; Uncoupling protein 1