Dikov 2010 Exp Gerontol
|Dikov D, Aulbach A, Muster B, Dröse S, Jendrach M, Bereiter-Hahn J (2010) Do UCP2 and mild uncoupling improve longevity? Exp Gerontol 45:586-95.|
Abstract: Mild uncoupling of mitochondrial respiration is considered to prolong life span of organisms by reducing the production of reactive oxygen species (ROS). Experimental evidence against this hypothesis has been brought forward by premature senescence in cell cultures treated with uncouplers. Exposing HUVEC to a mixture of nutritionally important fatty acids (oil extract of chicken yolk) mild uncoupling with "naturally acting substances" was performed. This treatment also resulted in premature senescence although ROS production did not increase. Fatty acids activate uncoupling proteins (UCP) in the inner mitochondrial membrane. UCP2 expression proved to be sensitive to the presence of fatty acids but remains unchanged during the ageing process. UCP3 expression in senescent HUVEC and avUCP expression in senescent CEF were considerably less than in young cultures. No indication for protonophoric reduction of mitochondrial membrane potential was found in UCP2 overexpressing HeLa cells and only little in HUVEC. ROS levels increased instead of being reduced in these cells. Stable transfection with UCP2-GFP was possible only in chick embryo fibroblasts and HeLa cells and resulted in decreased proliferation. Stable transfection of HUVEC with UCP2-GFP resulted in death of cultures within one or two weeks. The reason for this behaviour most probably is apoptosis preceded by mitochondrial fragmentation and loss of membrane potential.
• Keywords: Uncoupler, Longevity, ROS, UCP2/3, Fatty acids, Mitochondrial membrane potential, HUVEC
Labels: MiParea: Respiration Pathology: Aging;senescence Stress:Oxidative stress;RONS
Tissue;cell: HeLa, Fibroblast, HUVEC Preparation: Intact cells Enzyme: Complex IV;cytochrome c oxidase, Complex V;ATP synthase, Uncoupling protein Regulation: mt-Membrane potential, Uncoupler, Fatty acid Coupling state: LEAK, ROUTINE, ET
Abbreviations: mtΔψ, mitochondrial inner membrane potential; CEF, chick embryo fibroblasts; DASPMI, di-aminostyryl-methyl-pyrimidinium iodine; DHE, dihydro-ethidium; FCCP, carbonyl cyanid-p-triflouromethoxyphenylhydrazin; HUVEC, human umbilical vein endothelial cells; ROS, reactive oxygen species; TMRE, tetramethyl-rhodamine-ethylester