State Key Laboratory on Animal Nutrition, China Agricultural University, No. 2. Yuanmingyuan West Road, 100193 Beijing, China.
Mol Biol Rep. 2011 Jun;38(5):3201-6. doi: 10.1007/s11033-010-9992-6. Epub 2010 Feb 12.
Leptin plays a critical role in regulating muscle protein metabolism by binding with leptin receptors in a 1:1 stoichiometry. However, the role for leucine in the regulation of leptin receptor expression in muscle has not been investigated. The present study was conducted to test the hypothesis that leucine regulates leptin receptor levels in C2C12 myotubes. Cells were cultured in the presence of DMEM/F12 medium containing supplemental 0 or 5 mM L: -leucine. Leptin receptor expression by C2C12 myotubes peaked at 2 h post-supplementation. Additionally, leucine stimulated leptin receptor expression at both mRNA and protein levels in a dose-dependent manner. Furthermore, leucine enhanced the phosphorylation of mammalian target of rapamycin (mTOR). Addition of rapamycin (an inhibitor of mTOR) to culture medium completely suppressed leucine-induced activation of mTOR and inhibited leucine-stimulated leptin receptor production. These results indicate that leucine affects leptin receptor expression in muscle cells via the mTOR signaling pathway.
瘦素通过与瘦素受体以 1:1 的化学计量比结合，在调节肌肉蛋白质代谢中起着关键作用。然而，亮氨酸在调节肌肉中瘦素受体表达中的作用尚未得到研究。本研究旨在验证亮氨酸是否调节 C2C12 肌管中瘦素受体水平的假说。细胞在含有补充的 0 或 5 mM L：-亮氨酸的 DMEM/F12 培养基中培养。C2C12 肌管中的瘦素受体表达在补充后 2 小时达到峰值。此外，亮氨酸以剂量依赖性方式刺激瘦素受体在 mRNA 和蛋白质水平上的表达。此外，亮氨酸增强了雷帕霉素靶蛋白（mTOR）的磷酸化。向培养基中添加雷帕霉素（mTOR 的抑制剂）完全抑制了亮氨酸诱导的 mTOR 激活，并抑制了亮氨酸刺激的瘦素受体产生。这些结果表明，亮氨酸通过 mTOR 信号通路影响肌肉细胞中的瘦素受体表达。
