title: Low culture temperature inhibits myogenic differentiation through mitochondrial activity.
abstract: A previous study by our group reported that mouse and human myoblasts fail to express myogenin and to fuse into multi-nucleate myotubes when cultured at low temperature, such as 30°C, but that this activity is rescued by adding IGF-I and vitamin C to the culture medium. In the present study, we examined mitochondrial activity as a target of the inhibitory effects of the low culture temperature. It has been suggested that mitochondria regulate myogenesis. By using a mouse myoblast cell line C2C12, we demonstrate that the expression of cytochrome c oxidase subunit I (COX I), which is encoded in mitochondrial genome, increases during myogenic differentiation at the normal culture temperature (38°C), but that this up-regulation is inhibited at 30°C. The mitochondrial membrane potential also decreased at 30°C compared to the culture at 38°C. However, IGF-I and vitamin C rescued both COX I expression and mitochondrial membrane potential at 30°C as promoting muscle differentiation. We also find that the rescue of mitochondrial activity by IGF-I and vitamin C at 30°C occurred after the myogenin expression, which suggests that myogenin regulates mitochondrial function during myogenesis. We suggest that our low temperature-culture system may be suitable for use in studying the detailed mechanism of myogenin-related phenomena during myogenesis.
authors.affiliation: Department of Physiology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
authors.forename: Ai
authors.initials: A
authors.lastname: Shima
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Matsuda
mesh_terms: D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000502:physiology*; D002460:Cell Line; D003080:Cold Temperature; D003576:Electron Transport Complex IV / Q000235:genetics / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D053078:Membrane Potential, Mitochondrial / Q000502:physiology; D051379:Mice; D008928:Mitochondria / Q000502:physiology*; D032446:Myoblasts / Q000502:physiology*
chemical_list: D007334:Insulin-Like Growth Factor I; D003576:Electron Transport Complex IV; D001205:Ascorbic Acid
keywords: IGF; mitochondria; myogenesis; myogenin; skeletal muscle; temperature; vitamin C