Institute of Physical Education, Shaanxi University of Technology.
School of Biological Science and Engineering, Shaanxi University of Technology.
Genes Genet Syst. 2024 May 10;99. doi: 10.1266/ggs.23-00320. Epub 2024 Apr 18.
Homeostasis is essential for muscle repair and regeneration after skeletal muscle exercise. This study investigated the role of methyltransferase-like 21C (METTL21C) in skeletal muscle of mice after exercise and the potential mechanism. First, muscle samples were collected at 2, 4 and 6 weeks after exercise, and liver glycogen, muscle glycogen, blood lactic acid and triglyceride were assessed. Moreover, the expression levels of autophagy markers and METTL21C in skeletal muscle were analyzed. The results showed that the expression levels of METTL21C and MYH7 in the gastrocnemius muscle of mice in the exercise group were significantly higher after exercise than those in the control group, which suggested that long-term exercise promoted the formation of slow-twitch muscle fibers in mouse skeletal muscle. Likewise, the autophagy capacity was enhanced with the prolongation of exercise in muscles. The findings were confirmed in mouse C2C12 cells. We discovered that knockdown of Mettl21c reduced the expression of MYH7 and the autophagy level in mouse myoblasts. These findings indicate that METTL21C promotes skeletal muscle homeostasis after exercise by enhancing autophagy, and also contributes to myogenic differentiation and the formation of slow muscle fibers.
肌肉运动后，维持肌肉修复和再生的内环境稳定至关重要。本研究旨在探讨甲基转移酶样蛋白 21C（METTL21C）在运动后小鼠骨骼肌中的作用及其潜在机制。首先，在运动后 2、4 和 6 周采集肌肉样本，评估肝糖原、肌糖原、血乳酸和甘油三酯水平。此外，分析骨骼肌中自噬标志物和 METTL21C 的表达水平。结果表明，运动组小鼠比对照组在运动后腓肠肌中 METTL21C 和 MYH7 的表达水平明显升高，这表明长期运动促进了小鼠骨骼肌中慢肌纤维的形成。同样，随着运动时间的延长，肌肉中的自噬能力也增强。在 C2C12 细胞中的研究结果也证实了这一点。我们发现，Mettl21c 的敲低降低了 MYH7 的表达和小鼠成肌细胞中的自噬水平。这些发现表明，METTL21C 通过增强自噬来促进运动后的肌肉内环境稳定，也有助于肌生成分化和慢肌纤维的形成。
