Specific protein changes contribute to the differential muscle mass loss during ageing |
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Authors: | Daniele Capitanio Michele Vasso Sara De Palma Chiara Fania Enrica Torretta Francesco P Cammarata Valerio Magnaghi Patrizia Procacci Cecilia Gelfi |
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Institution: | 1. Department of Biomedical Sciences for Health, University of Milan, Milan, Italy;2. IRCCS Policlinico San Donato, San Donato Milanese (MI), Italy;3. Institute of Bioimaging and Molecular Physiology, National Research Council, Segrate (MI) – Cefalù (PA), Italy;4. Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy |
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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. |
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Keywords: | Animal proteomics 2D‐DIGE Intermediate metabolism Mass spectrometry Muscle ageing Muscle proteome |
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