DMEM, University of Montpellier, INRAE, Montpellier, France; Laboratoire d'Innovation thérapeutique, Lebanese University, Beyrouth, Liban.
DMEM, University of Montpellier, INRAE, Montpellier, France.
Meat Sci. 2022 Mar;185:108726. doi: 10.1016/j.meatsci.2021.108726. Epub 2021 Dec 24.
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 Ca-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.
肌肉生长抑制素缺乏导致广泛的骨骼肌肥大，但它对死后肌肉蛋白水解的影响尚不清楚。在这里，我们比较了野生型（WT）和肌肉生长抑制素敲除（KO）小鼠在死后早期储存过程中肌肉肌原纤维蛋白降解、自噬、泛素-蛋白酶体和 Ca 依赖性蛋白水解与能量和氧化还原状态的关系。与 WT 肌肉相比，KO 肌肉在死后 24 小时内表现出更高的肌原纤维蛋白降解，同时保持抗氧化状态。对关键自噬和泛素-蛋白酶体系统标志物的分析表明，这两条途径在死后肌肉（两种基因型）中没有上调，但 KO 肌肉中的基础自噬通量和 ATP 含量较低。蛋白酶体和半胱天冬酶活性在 WT 和 KO 小鼠之间没有差异。相反，钙蛋白酶活性在 KO 肌肉中较高，同时肌钙蛋白 T 和结蛋白降解增加。总的来说，这些结果表明，钙蛋白酶而不是自噬、蛋白酶体和半胱天冬酶系统，解释了两种基因型死后肌肉蛋白水解的差异。
