Graduate School of Medicine, Science and Technology, Shinshu University, Nagano, 399-4598, Japan.
Graduate School of Medicine, Science and Technology, Shinshu University, Nagano, 399-4598, Japan; Department of Biomolecular Innovation, Institute for Biomedical Sciences, Shinshu University, Nagano, 399-4598, Japan.
Biochem Biophys Res Commun. 2022 Dec 20;635:161-168. doi: 10.1016/j.bbrc.2022.10.018. Epub 2022 Oct 14.
Mild heat stimulation is defined as a stimulation that occurs several degrees above optimal cell culture or body temperatures. Muscle hypertrophy in C2C12 cells is reportedly facilitated by 39 °C mild heat stimulation. However, the underlying molecular mechanisms by which 39 °C mild heat stimulation promotes muscle hypertrophy remains elusive. In this study, we aimed at understanding the details of these mechanisms. First, we found that 39 °C mild heat stimulation has little or no effect on Myogenesis-Related Factor (MRF) expression both in C2C12 and mouse primary satellite cells. Therefore, we hypothesized that 39 °C mild heat stimulation promotes muscle hypertrophy through myokines, essential components in myogenesis. Interestingly, we observed muscle hypertrophy in the group cultured at 37 °C in conditioned medium from 39 °C compared to the group cultured at 37 °C in conditioned medium from 37 °C in the case of both C2C12 and mouse primary satellite cells. These results suggest that 39 °C mild heat stimulation promotes muscle hypertrophy through myokines, once released in the culture medium. Finally, we identified Decorin as a hypertrophy-inducing myokine candidate. Therefore, in this study, we demonstrated that 39 °C mild heat stimulation contributes to muscle hypertrophy through enhancing Decorin gene expression in C2C12 and mouse primary satellite cells.
轻度热刺激被定义为发生在最佳细胞培养或体温几度以上的刺激。据报道，39°C 的轻度热刺激促进 C2C12 细胞中的肌肉肥大。然而，39°C 轻度热刺激促进肌肉肥大的潜在分子机制仍不清楚。在这项研究中，我们旨在了解这些机制的细节。首先，我们发现 39°C 的轻度热刺激对 C2C12 和小鼠原代卫星细胞中的肌生成相关因子（MRF）表达几乎没有影响。因此，我们假设 39°C 的轻度热刺激通过肌肉因子促进肌肉肥大，肌肉因子是肌肉生成中的重要组成部分。有趣的是，我们观察到在 C2C12 和小鼠原代卫星细胞中，与在 37°C 条件培养基中培养的细胞相比，在 39°C 条件培养基中培养的细胞发生了肌肉肥大。这些结果表明，39°C 的轻度热刺激通过在培养基中释放的肌肉因子促进肌肉肥大。最后，我们确定了 Decorin 是一种诱导肌肉肥大的肌肉因子候选物。因此，在这项研究中，我们证明了 39°C 的轻度热刺激通过增强 C2C12 和小鼠原代卫星细胞中的 Decorin 基因表达来促进肌肉肥大。
