title: Overexpression of peroxisome proliferator-activated receptor gamma co-activator-1alpha leads to muscle atrophy with depletion of ATP.
abstract: Peroxisome proliferator-activated receptor-gamma co-activator-1alpha (PGC-1alpha) is a key nuclear receptor co-activator for mitochondrial biogenesis. Here we report that overexpression of PGC-1alpha in skeletal muscles increased mitochondrial number and caused atrophy of skeletal muscle, especially type 2B fiber-rich muscles (gastrocnemius, quadriceps, and plantaris). Muscle atrophy became evident at 25 weeks of age, and a portion of the muscle was replaced by adipocytes. Mice showed increased energy expenditure and reduced body weight; thyroid hormone levels were normal. Mitochondria exhibited normal respiratory chain activity per mitochondrion; however, mitochondrial respiration was not inhibited by an ATP synthase inhibitor, oligomycin, clearly indicating that oxidative phosphorylation was uncoupled. Accordingly, ATP content in gastrocnemius was markedly reduced. A similar phenotype is observed in Luft's disease, a mitochondrial disorder that involves increased uncoupling of respiration and muscle atrophy. Our results indicate that overexpression of PGC-1alpha in skeletal muscle increases not only mitochondrial biogenesis but also uncoupling of respiration, resulting in muscle atrophy.
authors.affiliation: Nutritional Science Program, National Institute of Health and Nutrition, 1-23-1, Toyama, Shinjuku-ku, Tokyo 162-8636, Japan. shinjim@nih.go.jp
authors.forename: Shinji
authors.initials: S
authors.lastname: Miura
authors.forename: Eriko
authors.initials: E
authors.lastname: Tomitsuka
authors.forename: Yasutomi
authors.initials: Y
authors.lastname: Kamei
authors.forename: Tomomi
authors.initials: T
authors.lastname: Yamazaki
authors.forename: Yuko
authors.initials: Y
authors.lastname: Kai
authors.forename: Mayumi
authors.initials: M
authors.lastname: Tamura
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Kita
authors.forename: Ichizo
authors.initials: I
authors.lastname: Nishino
authors.forename: Osamu
authors.initials: O
authors.lastname: Ezaki
mesh_terms: D000255:Adenosine Triphosphate / Q000172:deficiency*; D017667:Adipocytes / Q000473:pathology; D000818:Animals; D001835:Body Weight / Q000235:genetics; D049109:Cell Proliferation; D019069:Cell Respiration; D005260:Female; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D008931:Mitochondria, Muscle / Q000378:metabolism / Q000648:ultrastructure; D018482:Muscle, Skeletal / Q000378:metabolism / Q000648:ultrastructure; D009133:Muscular Atrophy / Q000235:genetics* / Q000473:pathology; D010085:Oxidative Phosphorylation; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D015534:Trans-Activators / Q000235:genetics*; D014157:Transcription Factors; D015533:Transcriptional Activation
chemical_list: D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; C485290:Ppargc1a protein, mouse; D015534:Trans-Activators; D014157:Transcription Factors; D000255:Adenosine Triphosphate