Department of Chemistry and Biochemistry, Laurentian University, Sudbury, ON, Canada.
Cardiovascular and Metabolic Research Unit, Laurentian University, Sudbury, ON, Canada.
FASEB J. 2021 May;35(5):e21511. doi: 10.1096/fj.202002675R.
Hydrogen sulfide (H S) can be endogenously produced and belongs to the class of signaling molecules known as gasotransmitters. Cystathionine gamma-lyase (CSE)-derived H S is implicated in the regulation of cell differentiation and the aging process, but the involvements of the CSE/H S system in myogenesis upon aging and injury have not been explored. In this study, we demonstrated that CSE acts as a major H S-generating enzyme in skeletal muscles and is significantly down-regulated in aged skeletal muscles in mice. CSE deficiency exacerbated the age-dependent sarcopenia and cardiotoxin-induced injury/regeneration in mouse skeletal muscle, possibly attributed to inefficient myogenesis. In contrast, supplement of NaHS (an H S donor) induced the expressions of myogenic genes and promoted muscle regeneration in mice. In vitro, incubation of myoblast cells (C2C12) with H S promoted myogenesis, as evidenced by the inhibition of cell cycle progression and migration, altered expressions of myogenic markers, elongation of myoblasts, and formation of multinucleated myotubes. Myogenesis was also found to upregulate CSE expression, while blockage of CSE/H S signaling resulted in a suppression of myogenesis. Mechanically, H S significantly induced the heterodimer formation between MEF2c and MRF4 and promoted the binding of MEF2c/MRF4 to myogenin promoter. MEF2c was S-sulfhydrated at both cysteine 361 and 420 in the C-terminal transactivation domain, and blockage of MEF2c S-sulfhydration abolished the stimulatory role of H S on MEF2c/MRF4 heterodimer formation. These findings support an essential role for H S in maintaining myogenesis, presenting it as a potential candidate for the prevention of age-related sarcopenia and treatment of muscle injury.
硫化氢（H2S）可以内源性产生，属于被称为气体信号分子的信号分子类。胱硫醚γ-裂解酶（CSE）衍生的 H2S 参与细胞分化和衰老过程的调节，但 CSE/H2S 系统在衰老和损伤时对肌生成的参与尚未被探索。在这项研究中，我们证明 CSE 是骨骼肌中主要的 H2S 生成酶，并且在小鼠衰老骨骼肌中显著下调。CSE 缺乏加剧了与年龄相关的骨骼肌减少症和肌肉毒素诱导的损伤/再生，可能归因于无效的肌生成。相比之下，补充 NaHS（H2S 供体）诱导了小鼠肌肉中的肌生成基因表达，并促进了肌肉再生。在体外，将 H2S 孵育于肌母细胞（C2C12）中促进了肌生成，这表现在细胞周期进程和迁移的抑制、肌生成标志物的表达改变、肌母细胞的伸长和多核肌管的形成。还发现肌生成上调 CSE 表达，而阻断 CSE/H2S 信号导致肌生成抑制。机制上，H2S 显著诱导 MEF2c 和 MRF4 之间的异二聚体形成，并促进 MEF2c/MRF4 与肌生成素启动子的结合。MEF2c 在 C 端转录激活域中的半胱氨酸 361 和 420 处被 S-巯基化，阻断 MEF2c S-巯基化消除了 H2S 对 MEF2c/MRF4 异二聚体形成的刺激作用。这些发现支持 H2S 在维持肌生成中的重要作用，为预防与年龄相关的骨骼肌减少症和治疗肌肉损伤提供了一个潜在的候选物。
