title: Extracellular Redox Regulation of Intracellular Reactive Oxygen Generation, Mitochondrial Function and Lipid Turnover in Cultured Human Adipocytes.
abstract: Many tissues play an important role in metabolic homeostasis and the development of diabetes and obesity. We hypothesized that the circulating redox metabolome is a master metabolic regulatory system that impacts all organs and modulates reactive oxygen species (ROS) production, lipid peroxidation, energy production and changes in lipid turnover in many cells including adipocytes.
  
  
  
  Differentiated human preadipocytes were exposed to the redox couples, lactate (L) and pyruvate (P), β-hydroxybutyrate (βOHB) and acetoacetate (Acoc), and the thiol-disulfides cysteine/ cystine (Cys/CySS) and GSH/GSSG for 1.5-4 hours. ROS measurements were done with CM-H2DCFDA. Lipid peroxidation (LPO) was assessed by a modification of the thiobarbituric acid method. Lipolysis was measured as glycerol release. Lipid synthesis was measured as 14C-glucose incorporated into lipid. Respiration was assessed using the SeaHorse XF24 analyzer and the proton leak was determined from the difference in respiration with oligomycin and antimycin A.
  
  
  
  Metabolites with increasing oxidation potentials (GSSG, CySS, Acoc) increased adipocyte ROS. In contrast, P caused a decrease in ROS compared with L. Acoc also induced a significant increase in both LPO and lipid synthesis. L and Acoc increased lipolysis. βOHB increased respiration, mainly due to an increased proton leak. GSSG, when present throughout 14 days of differentiation significantly increased fat accumulation, but not when added later.
  
  
  
  We demonstrated that in human adipocytes changes in the external redox state impacted ROS production, LPO, energy efficiency, lipid handling, and differentiation. A more oxidized state generally led to increased ROS, LPO and lipid turnover and more reduction led to increased respiration and a proton leak. However, not all of the redox couples were the same suggesting compartmentalization. These data are consistent with the concept of the circulating redox metabolome as a master metabolic regulatory system.
authors.affiliation: Obesity Research Center, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America.
authors.forename: Albert R
authors.initials: AR
authors.lastname: Jones
authors.affiliation: Obesity Research Center, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America.
authors.forename: Tova
authors.initials: T
authors.lastname: Meshulam
authors.affiliation: Obesity Research Center, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America.|Laboratório de Bioquímica de Resposta ao Estresse, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Cidade Universitária, Rio de Janeiro, Brazil.
authors.forename: Marcus F
authors.initials: MF
authors.lastname: Oliveira
authors.affiliation: Obesity Research Center, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America.
authors.forename: Nathan
authors.initials: N
authors.lastname: Burritt
authors.affiliation: Obesity Research Center, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America.
authors.forename: Barbara E
authors.initials: BE
authors.lastname: Corkey
mesh_terms: D020155:3-Hydroxybutyric Acid / Q000494:pharmacology; D000090:Acetoacetates / Q000494:pharmacology; D017667:Adipocytes / Q000166:cytology / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D003545:Cysteine / Q000378:metabolism; D005947:Glucose / Q000494:pharmacology; D005978:Glutathione / Q000378:metabolism; D005990:Glycerol / Q000378:metabolism; D006801:Humans; D007657:Ketone Bodies / Q000494:pharmacology; D007773:Lactates / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D050155:Lipogenesis / Q000187:drug effects; D008928:Mitochondria / Q000378:metabolism*; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D017382:Reactive Oxygen Species / Q000378:metabolism*
chemical_list: D000090:Acetoacetates; D007657:Ketone Bodies; D007773:Lactates; D017382:Reactive Oxygen Species; D005576:Colforsin; C016635:acetoacetic acid; D005978:Glutathione; D005947:Glucose; D003545:Cysteine; D005990:Glycerol; D020155:3-Hydroxybutyric Acid