title: The fine tuning of metabolism, autophagy and differentiation during in vitro myogenesis.
abstract: Although the mechanisms controlling skeletal muscle homeostasis have been identified, there is a lack of knowledge of the integrated dynamic processes occurring during myogenesis and their regulation. Here, metabolism, autophagy and differentiation were concomitantly analyzed in mouse muscle satellite cell (MSC)-derived myoblasts and their cross-talk addressed by drug and genetic manipulation. We show that increased mitochondrial biogenesis and activation of mammalian target of rapamycin complex 1 inactivation-independent basal autophagy characterize the conversion of myoblasts into myotubes. Notably, inhibition of autophagic flux halts cell fusion in the latest stages of differentiation and, conversely, when the fusion step of myocytes is impaired the biogenesis of autophagosomes is also impaired. By using myoblasts derived from p53 null mice, we show that in the absence of p53 glycolysis prevails and mitochondrial biogenesis is strongly impaired. P53 null myoblasts show defective terminal differentiation and attenuated basal autophagy when switched into differentiating culture conditions. In conclusion, we demonstrate that basal autophagy contributes to a correct execution of myogenesis and that physiological p53 activity is required for muscle homeostasis by regulating metabolism and by affecting autophagy and differentiation.
authors.affiliation: Department of Environment and Primary Prevention, Molecular Epidemiology Unit, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Fortini
authors.affiliation: Department of Environment and Primary Prevention, Molecular Epidemiology Unit, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Ferretti
authors.affiliation: Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Iorio
authors.affiliation: Department of Health Sciences, Università del Piemonte Orientale 'Amedeo Avogadro', Novara, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Cagnin
authors.affiliation: Department of Environment and Primary Prevention, Molecular Epidemiology Unit, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Garribba
authors.affiliation: Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Pietraforte
authors.affiliation: National AIDS Center, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Falchi
authors.affiliation: Department of Environment and Primary Prevention, Molecular Epidemiology Unit, Istituto Superiore di Sanità, Rome, Italy.|Institute of Crystallography, Consiglio Nazionale delle Ricerche, Rome, Italy.
authors.forename: B
authors.initials: B
authors.lastname: Pascucci
authors.affiliation: Department of Environment and Primary Prevention, Molecular Epidemiology Unit, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Baccarini
authors.affiliation: Department of Health Sciences, Università del Piemonte Orientale 'Amedeo Avogadro', Novara, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Morani
authors.affiliation: Department of Health Sciences, Università del Piemonte Orientale 'Amedeo Avogadro', Novara, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Phadngam
authors.affiliation: Department of Haematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: G
authors.initials: G
authors.lastname: De Luca
authors.affiliation: Department of Health Sciences, Università del Piemonte Orientale 'Amedeo Avogadro', Novara, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Isidoro
authors.affiliation: Department of Environment and Primary Prevention, Molecular Epidemiology Unit, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Dogliotti
mesh_terms: D000643:Ammonium Chloride / Q000494:pharmacology; D000818:Animals; D001343:Autophagy / Q000187:drug effects; D000071186:Beclin-1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D007976:Leupeptins / Q000494:pharmacology; D000076222:Mechanistic Target of Rapamycin Complex 1; D051379:Mice; D018345:Mice, Knockout; D018613:Microscopy, Confocal; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism*; D046912:Multiprotein Complexes / Q000378:metabolism; D018485:Muscle Fibers, Skeletal / Q000166:cytology / Q000378:metabolism; D032446:Myoblasts / Q000166:cytology* / Q000378:metabolism; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D032496:Satellite Cells, Skeletal Muscle / Q000166:cytology*; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000172:deficiency / Q000235:genetics
chemical_list: D000071186:Beclin-1; D007976:Leupeptins; C480860:Map1lc3b protein, mouse; D008869:Microtubule-Associated Proteins; D046912:Multiprotein Complexes; D034741:RNA, Small Interfering; D016159:Tumor Suppressor Protein p53; D000643:Ammonium Chloride; D000076222:Mechanistic Target of Rapamycin Complex 1; D058570:TOR Serine-Threonine Kinases; C032854:leupeptin