Transgenic UCP1 in white adipocytes modulates mitochondrial membrane potential

• Published in: FEBS letters 1999-02, Vol.444 (2), p.206-210
• Main Authors: Baumruk, Filip, Flachs, Pavel, Horáková, Milada, Floryk, Daniel, Kopecký, Jan
• Format: Article
• Language: English
• Subjects: Adipocytes - metabolism; Animals; aP2-Ucp mice, transgenic mice with synthesis of UCP1 from adipocyte lipid binding protein promoter; BSA, bovine serum albumin; Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone - pharmacology; Carrier Proteins - genetics; Carrier Proteins - metabolism; Cell Membrane Permeability - drug effects; Energy metabolism; Fatty Acids - metabolism; FCCP, carbonylcyanide p-trifluoromethoxyphenylhydrazone; Female; Flow Cytometry; Fluorescent Dyes - metabolism; Guanosine Diphosphate - metabolism; IFL, mean fluorescence; Ion Channels; KCl buffer, 100 mM KCl, 10 mM Tris, 2 mM MgCl2, 4 mM K2HPO4 and 1 mM EDTA; Membrane Potentials - genetics; Membrane Proteins - genetics; Membrane Proteins - metabolism; Membrane Transport Proteins; Mice; Mice, Transgenic; Mitochondria - genetics; Mitochondrial Proteins; Obesity - metabolism; Oxidative phosphorylation; Proteins - metabolism; Proton leak; Tetramethylrhodamine methyl ester; TMRM, tetramethylrhodamine methyl ester; UCP, uncoupling protein; Uncoupling Protein 1; Uncoupling Protein 2; ΔΨ m, mitochondrial membrane potential
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/S0014-5793(99)00053-8

To test if mitochondrial uncoupling in white adipocytes is responsible for obesity resistance of the aP2- Ucp transgenic mice expressing ectopic uncoupling protein 1 (UCP1) in white fat, mitochondrial membrane potential (Δ Ψ m) was estimated by flow cytometry in adipocytes isolated from gonadal fat. Ectopic UCP1 (approximately 0.8 mol UCP1/mol respiratory chain) decreased the Δ Ψ m and rendered the potential sensitive to GDP and fatty acids. These ligands of UCP1 had no effect on Δ Ψ m in white adipocytes from non-transgenic mice, suggesting that the function of endogenous UCP2 in adipocytes was not affected. The results support the hypothesis that mitochondrial uncoupling in white fat may prevent development of obesity.