title: Specific protein changes contribute to the differential muscle mass loss during ageing.
abstract: In the skeletal muscle, the ageing process is characterized by a loss of muscle mass and strength, coupled with a decline of mitochondrial function and a decrease of satellite cells. This profile is more pronounced in hindlimb than in forelimb muscles, both in humans and in rodents. Utilizing light and electron microscopy, myosin heavy chain isoform distribution, proteomic analysis by 2D-DIGE, MALDI-TOF MS and quantitative immunoblotting, this study analyzes the protein levels and the nuclear localization of specific molecules, which can contribute to a preferential muscle loss. Our results identify the molecular changes in the hindlimb (gastrocnemius) and forelimb (triceps) muscles during ageing in rats (3- and 22-month-old). Specifically, the oxidative metabolism contributes to tissue homeostasis in triceps, whereas respiratory chain disruption and oxidative-stress-induced damage imbalance the homeostasis in gastrocnemius muscle. High levels of dihydrolipoyllysine-residue acetyltransferase (Dlat) and ATP synthase subunit alpha (Atp5a1) are detected in triceps and gastrocnemius, respectively. Interestingly, in triceps, both molecules are increased in the nucleus in aged rats and are associated to an increased protein acetylation and myoglobin availability. Furthermore, autophagy is retained in triceps whereas an enhanced fusion, decrement of mitophagy and of regenerative potential is observed in aged gastrocnemius muscle.
authors.affiliation: Department of Biomedical Sciences for Health, University of Milan, Milan, Italy.|IRCCS Policlinico San Donato, San Donato Milanese (MI), Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Capitanio
authors.affiliation: Institute of Bioimaging and Molecular Physiology, National Research Council, Segrate (MI) - Cefalù (PA), Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Vasso
authors.affiliation: Institute of Bioimaging and Molecular Physiology, National Research Council, Segrate (MI) - Cefalù (PA), Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: De Palma
authors.affiliation: Department of Biomedical Sciences for Health, University of Milan, Milan, Italy.|IRCCS Policlinico San Donato, San Donato Milanese (MI), Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Fania
authors.affiliation: Department of Biomedical Sciences for Health, University of Milan, Milan, Italy.|IRCCS Policlinico San Donato, San Donato Milanese (MI), Italy.
authors.forename: Enrica
authors.initials: E
authors.lastname: Torretta
authors.affiliation: Institute of Bioimaging and Molecular Physiology, National Research Council, Segrate (MI) - Cefalù (PA), Italy.
authors.forename: Francesco P
authors.initials: FP
authors.lastname: Cammarata
authors.affiliation: Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy.
authors.forename: Valerio
authors.initials: V
authors.lastname: Magnaghi
authors.affiliation: Department of Biomedical Sciences for Health, University of Milan, Milan, Italy.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Procacci
authors.affiliation: Department of Biomedical Sciences for Health, University of Milan, Milan, Italy.|IRCCS Policlinico San Donato, San Donato Milanese (MI), Italy.|Institute of Bioimaging and Molecular Physiology, National Research Council, Segrate (MI) - Cefalù (PA), Italy.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Gelfi
mesh_terms: D000375:Aging; D000818:Animals; D001343:Autophagy; D008297:Male; D008928:Mitochondria / Q000378:metabolism / Q000473:pathology; D009124:Muscle Proteins / Q000032:analysis* / Q000378:metabolism; D018482:Muscle, Skeletal / Q000473:pathology* / Q000502:physiology; D009135:Muscular Diseases / Q000378:metabolism / Q000473:pathology*; D018995:Myosin Heavy Chains / Q000032:analysis / Q000378:metabolism; D040901:Proteomics; D017207:Rats, Sprague-Dawley; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D057825:Two-Dimensional Difference Gel Electrophoresis
chemical_list: D009124:Muscle Proteins; D018995:Myosin Heavy Chains
keywords: 2D-DIGE; Animal proteomics; Intermediate metabolism; Mass spectrometry; Muscle ageing; Muscle proteome