Myostatin gene inactivation increases post-mortem calpain-dependent muscle proteolysis in mice

• Published in: Meat science Vol. 185; p. 108726
• Main Authors: Nassar, Rim, Vernus, Barbara, Carnac, Gilles, Fouret, Gilles, Goustard, Bénédicte, Casas, François, Tintignac, Lionel, Cassar-Malek, Isabelle, Picard, Brigitte, Seiliez, Iban, Brioche, Thomas, Koechlin-Ramonatxo, Christelle, Bertrand-Gaday, Christelle, Hamade, Aline, Najjar, Fadia, Chabi, Béatrice, Bonnieu, Anne
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.03.2022
• Subjects: Animals; Calpain - genetics; Calpain - metabolism; Gene Silencing; Mice; Muscle, Skeletal - metabolism; Myofibrillar protein; Myostatin - genetics; Oxidative stress; Post-mortem; Proteolysis; Skeletal muscle; Oxidative stress; Myofibrillar protein; Post-mortem; Proteolysis; Skeletal muscle
• DOI: 10.1016/j.meatsci.2021.108726
• ISSN: 0309-1740

Myostatin deficiency leads to extensive skeletal muscle hypertrophy, but its consequence on post-mortem muscle proteolysis is unknown. Here, we compared muscle myofibrillar protein degradation, and autophagy, ubiquitin-proteasome and Ca2+-dependent proteolysis relative to the energetic and redox status in wild-type (WT) and myostatin knock-out mice (KO) during early post-mortem storage. KO muscles showed higher degradation of myofibrillar proteins in the first 24 h after death, associated with preserved antioxidant status, compared with WT muscles. Analysis of key autophagy and ubiquitin-proteasome system markers indicated that these two pathways were not upregulated in post-mortem muscle (both genotypes), but basal autophagic flux and ATP content were lower in KO muscles. Proteasome and caspase activities were not different between WT and KO mice. Conversely, calpain activity was higher in KO muscles, concomitantly with higher troponin T and desmin degradation. Altogether, these results suggest that calpains but not the autophagy, proteasome and caspase systems, explain the difference in post-mortem muscle protein proteolysis between both genotypes. •Specific proteolytic changes in post-mortem skeletal muscle are observed upon myostatin deletion (Mstn KO).•Loss of myostatin increases protein breakdown in post-mortem skeletal muscle.•Autophagy and proteasome are active in post-mortem skeletal muscle.•The increased post-mortem proteolysis in Mstn KO mice might be attributed to the calpain system.