A treadmill exercise reactivates the signaling of the mammalian target of rapamycin (mTor) in the skeletal muscles of starved mice

作者：Zheng Dong Mei; Bian Zehua; Furuya Norihiko; Trejo Juan Alejandro Oliva; Takeda Ezaki Mitsue; Takahashi Katsuyuki; Hiraoka Yuka; Mineki Reiko; Taka Hikari; Ikeda Shin ichi; Komatsu Masaaki; Fujimura Tsutomu; Ueno Takashi; Ezaki Junji^*

来源：Biochemical and Biophysical Research Communications, 2015, 456(1): 519-526.

DOI：10.1016/j.bbrc.2014.11.118

• Autophagy
• Exercise
• Treadmill
• Skeletal muscle
• mTor
• GFP-LC3

It has been well established that a starvation-induced decrease in insulin/IGF-I and serum amino acids effectively suppresses the mammalian target of rapamycin (mTor) signaling to induce autophagy, which is a major degradative cellular pathway in skeletal muscles. In this study, we investigated the systematic effects of exercise on the mTor signaling of skeletal muscles. Wild type C57BL/6J mice were starved for 24 h under synchronous autophagy induction conditions. Under these conditions, endogenous LC3-II increased, while both S6-kinse and S6 ribosomal protein were dephosphorylated in the skeletal muscles, which indicated mTor inactivation. Using GFP-LC3 transgenic mice, it was also confirmed that fluorescent GFP-LC3 dots in the skeletal muscles increased, including soleus, plantaris, and gastrocnemius, which clearly showed autophagosomal induction. These starved mice were then subjected to a single bout of running on a treadmill (12 m/min, 2 h, with a lean of 10 degrees). Surprisingly, biochemical analyses revealed that the exercise elicited a decrease in the LC3-II/LC3-I ratio as well as an inversion from the dephosphorylated state to the rephosphorylated state of S6-kinase and ribosomal S6 in these skeletal muscles. Consistently, the GFP-LC3 dots of the skeletal muscles were diminished immediately after the exercise. These results indicated that exercise suppressed starvation-induced autophagy through a reactivation of mTor signaling in the skeletal muscles of these starved mice.

• 出版日期2015-1-2
• 单位河北医科大学