W F Theeuwes1, H R Gosker2, R C J Langen1, N A M Pansters1, A M W J Schols1, A H V Remels3. 1. NUTRIM School of Nutrition and Translational Research in Metabolism, Department of Respiratory Medicine, Maastricht University Medical Center+, Maastricht, The Netherlands. 2. NUTRIM School of Nutrition and Translational Research in Metabolism, Department of Respiratory Medicine, Maastricht University Medical Center+, Maastricht, The Netherlands. Electronic address: h.gosker@maastrichtuniversity.nl. 3. NUTRIM School of Nutrition and Translational Research in Metabolism, Department of Pharmacology and Toxicology, Maastricht University Medical Center+, Maastricht, The Netherlands.
Abstract
BACKGROUND: Mitochondrial biogenesis is crucial for myogenic differentiation and regeneration of skeletal muscle tissue and is tightly controlled by the peroxisome proliferator-activated receptor-γ co-activator 1 (PGC-1) signaling network. In the present study, we hypothesized that inactivation of glycogen synthase kinase (GSK)-3β, previously suggested to interfere with PGC-1 in non-muscle cells, potentiates PGC-1 signaling and the development of mitochondrial biogenesis during myogenesis, ultimately resulting in an enhanced myotube oxidative capacity. METHODS: GSK-3β was inactivated genetically or pharmacologically during myogenic differentiation of C2C12 muscle cells. In addition, m. gastrocnemius tissue was collected from wild-type and muscle-specific GSK-3β knock-out (KO) mice at different time-points during the reloading/regeneration phase following a 14-day hind-limb suspension period. Subsequently, expression levels of constituents of the PGC-1 signaling network as well as key parameters of mitochondrial oxidative metabolism were investigated. RESULTS: In vitro, both knock-down as well as pharmacological inhibition of GSK-3β not only increased expression levels of important constituents of the PGC-1 signaling network, but also potentiated myogenic differentiation-associated increases in mitochondrial respiration, mitochondrial DNA copy number, oxidative phosphorylation (OXPHOS) protein abundance and the activity of key enzymes involved in the Krebs cycle and fatty acid β-oxidation. In addition, GSK-3β KO animals showed augmented reloading-induced increases in skeletal muscle gene expression of constituents of the PGC-1 signaling network as well as sub-units of OXPHOS complexes compared to wild-type animals. CONCLUSION: Inactivation of GSK-3β stimulates activation of PGC-1 signaling and mitochondrial biogenesis during myogenic differentiation and reloading of the skeletal musculature.
BACKGROUND: Mitochondrial biogenesis is crucial for myogenic differentiation and regeneration of skeletal muscle tissue and is tightly controlled by the peroxisome proliferator-activated receptor-γ co-activator 1 (PGC-1) signaling network. In the present study, we hypothesized that inactivation of glycogen synthase kinase (GSK)-3β, previously suggested to interfere with PGC-1 in non-muscle cells, potentiates PGC-1 signaling and the development of mitochondrial biogenesis during myogenesis, ultimately resulting in an enhanced myotube oxidative capacity. METHODS: GSK-3β was inactivated genetically or pharmacologically during myogenic differentiation of C2C12 muscle cells. In addition, m. gastrocnemius tissue was collected from wild-type and muscle-specific GSK-3β knock-out (KO) mice at different time-points during the reloading/regeneration phase following a 14-day hind-limb suspension period. Subsequently, expression levels of constituents of the PGC-1 signaling network as well as key parameters of mitochondrial oxidative metabolism were investigated. RESULTS: In vitro, both knock-down as well as pharmacological inhibition of GSK-3β not only increased expression levels of important constituents of the PGC-1 signaling network, but also potentiated myogenic differentiation-associated increases in mitochondrial respiration, mitochondrial DNA copy number, oxidative phosphorylation (OXPHOS) protein abundance and the activity of key enzymes involved in the Krebs cycle and fatty acid β-oxidation. In addition, GSK-3β KO animals showed augmented reloading-induced increases in skeletal muscle gene expression of constituents of the PGC-1 signaling network as well as sub-units of OXPHOS complexes compared to wild-type animals. CONCLUSION: Inactivation of GSK-3β stimulates activation of PGC-1 signaling and mitochondrial biogenesis during myogenic differentiation and reloading of the skeletal musculature.
Authors: Megan E Rosa-Caldwell; Seongkyun Lim; Wesley S Haynie; Lisa T Jansen; Lauren C Westervelt; Madeline G Amos; Tyrone A Washington; Nicholas P Greene Journal: J Appl Physiol (1985) Date: 2020-09-17
Authors: Kennedy C Whitley; Sophie I Hamstra; Ryan W Baranowski; Colton J F Watson; Rebecca E K MacPherson; Adam J MacNeil; Brian D Roy; Rene Vandenboom; Val A Fajardo Journal: Physiol Rep Date: 2020-07