title: Mitochondrial DNA depletion and respiratory chain activity in primary human subcutaneous adipocytes treated with nucleoside analogue reverse transcriptase inhibitors.
abstract: Mitochondrial dysfunction as a consequence of mitochondrial DNA (mtDNA) depletion due to therapy with nucleoside analogue reverse transcriptase inhibitors (NRTI) has been proposed as a pathogenic mechanism leading to lipoatrophy in HIV-infected patients. The aim of our study was to investigate the impact of NRTI treatment on mtDNA abundance and the activities of respiratory chain complexes in primary human subcutaneous preadipocytes (phsPA). We studied adipocyte phenotypes, viability, and differentiation (CCAAT/enhancer-binding protein alpha [C/EBPalpha] and peroxisome proliferator-activated receptor gamma [PPARgamma] expression) and adiponectin production, mtDNA content, mitochondrial membrane potential, mitochondrial mass, and respiratory chain enzyme and citrate synthase activities in both proliferating and differentiating phsPA. Cells were exposed to zidovudine (6 microM), stavudine (d4T; 3 microM), and zalcitabine (ddC; 0.1 microM) for 8 weeks. NRTI-induced mtDNA depletion occurred in proliferating and differentiating phsPA after exposure to therapeutic drug concentrations of d4T and ddC. At these concentrations, ddC and d4T led to an almost 50% decrease in the number of mtDNA copies per cell without major impact on adipocyte differentiation. Despite mtDNA depletion by NRTI, the activities of the respiratory chain complexes, the mitochondrial membrane potential, and the mitochondrial mass were found to be unaffected. Severe NRTI-mediated mtDNA depletion in phsPA is not inevitably associated with impaired respiratory chain activity or altered mitochondrial membrane potential.
authors.affiliation: Clinic for Immunology and Rheumatology, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany.
authors.forename: Metodi V
authors.initials: MV
authors.lastname: Stankov
authors.forename: Thomas
authors.initials: T
authors.lastname: Lücke
authors.forename: Anibh M
authors.initials: AM
authors.lastname: Das
authors.forename: Reinhold E
authors.initials: RE
authors.lastname: Schmidt
authors.forename: Georg M N
authors.initials: GM
authors.lastname: Behrens
mesh_terms: D017667:Adipocytes / Q000187:drug effects* / Q000378:metabolism*; D001391:Azo Compounds; D002470:Cell Survival; D002478:Cells, Cultured; D004396:Coloring Agents; D004272:DNA, Mitochondrial / Q000378:metabolism*; D004579:Electron Transport / Q000502:physiology*; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D005989:Glycerides / Q000378:metabolism; D006801:Humans; D012313:RNA / Q000096:biosynthesis / Q000235:genetics; D018894:Reverse Transcriptase Inhibitors / Q000494:pharmacology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012867:Skin / Q000166:cytology
chemical_list: D001391:Azo Compounds; D004396:Coloring Agents; D004272:DNA, Mitochondrial; D005989:Glycerides; D018894:Reverse Transcriptase Inhibitors; D012313:RNA; C011049:oil red O