Haendeler 2009 Arterioscler Thromb Vasc Biol

Haendeler J, Dröse S, Büchner N, Jakob S, Altschmied J, Goy C, Spyridopoulos I, Zeiher AM, Brandt U, Dimmeler S (2009) Mitochondrial telomerase reverse transcriptase binds to and protects mitochondrial DNA and function from damage. Arterioscler. Thromb. Vasc. Biol. 29: 929-935.

» PMID: 19265030

Haendeler J, Droese S, Buechner N, Jakob S, Altschmied J, Goy C, Spyridopoulos I, Zeiher AM, Brandt U, Dimmeler S (2009) Arterioscler. Thromb. Vasc. Biol.

Abstract: Objective—The enzyme telomerase and its catalytic subunit the telomerase reverse transcriptase (TERT) are important for maintenance of telomere length in the nucleus. Recent studies provided evidence for a mitochondrial localization of TERT. Therefore, we investigated the exact localization of TERT within the mitochondria and its function.

Methods and Results—Here, we demonstrate that TERT is localized in the matrix of the mitochondria. TERT binds to mitochondrial DNA at the coding regions for ND1 and ND2. Binding of TERT to mitochondrial DNA protects against ethidium bromide–induced damage. TERT increases overall respiratory chain activity, which is most pronounced at complex I and dependent on the reverse transcriptase activity of the enzyme. Moreover, mitochondrial reactive oxygen species are increased after genetic ablation of TERT by shRNA. Mitochondrially targeted TERT and not wild-type TERT revealed the most prominent protective effect on H₂O₂ -induced apoptosis. Lung fibroblasts from 6-month-old TERT^-/- mice (F2 generation) showed increased sensitivity toward UVB radiation and heart mitochondria exhibited significantly reduced respiratory chain activity already under basal conditions, demonstrating the protective function of TERT in vivo.

Conclusion—Mitochondrial TERT exerts a novel protective function by binding to mitochondrial DNA, increasing respiratory chain activity and protecting against oxidative stress–induced damage. • Keywords: Aging, Apoptosis, Mitochondrial functions, Mitochondrial DNA, Reactive oxygen species, Telomerase reverse transcriptase

Labels:

Stress:RONS; Oxidative Stress"RONS; Oxidative Stress" is not in the list (Cell death, Cryopreservation, Ischemia-reperfusion, Permeability transition, Oxidative stress;RONS, Temperature, Hypoxia, Mitochondrial disease) of allowed values for the "Stress" property., Cancer; Apoptosis; Cytochrome c"Cancer; Apoptosis; Cytochrome c" is not in the list (Cell death, Cryopreservation, Ischemia-reperfusion, Permeability transition, Oxidative stress;RONS, Temperature, Hypoxia, Mitochondrial disease) of allowed values for the "Stress" property., Genetic Defect; Knockdown; Overexpression"Genetic Defect; Knockdown; Overexpression" is not in the list (Cell death, Cryopreservation, Ischemia-reperfusion, Permeability transition, Oxidative stress;RONS, Temperature, Hypoxia, Mitochondrial disease) of allowed values for the "Stress" property.  Organism: Human, Mouse  Tissue;cell: Fibroblast, Endothelial; Epithelial; Mesothelial Cell"Endothelial; Epithelial; Mesothelial Cell" is not in the list (Heart, Skeletal muscle, Nervous system, Liver, Kidney, Lung;gill, Islet cell;pancreas;thymus, Endothelial;epithelial;mesothelial cell, Blood cells, Fat, ...) of allowed values for the "Tissue and cell" property.  Preparation: Intact Cell; Cultured; Primary"Intact Cell; Cultured; Primary" is not in the list (Intact organism, Intact organ, Permeabilized cells, Permeabilized tissue, Homogenate, Isolated mitochondria, SMP, Chloroplasts, Enzyme, Oxidase;biochemical oxidation, ...) of allowed values for the "Preparation" property., Enzyme 

Regulation: Respiration; OXPHOS; ETS Capacity"Respiration; OXPHOS; ETS Capacity" is not in the list (Aerobic glycolysis, ADP, ATP, ATP production, AMP, Calcium, Coupling efficiency;uncoupling, Cyt c, Flux control, Inhibitor, ...) of allowed values for the "Respiration and regulation" property. 

HRR: Oxygraph-2k