Induction of Autophagy and Changes in Cellular Metabolism in Glucose Starved C2C12 Myotubes
Induction of Autophagy and Changes in Cellular Metabolism in Glucose Starved C2C12 Myotubes
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DOI：
10.3177/jnsv.66.41
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发表时间：
2020-01-01
影响因子：
1.6
通讯作者：
Higashida, Kazuhiko
中科院分区：
文献类型：
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作者：
Nakai, Naoya;Kitai, Saki;Higashida, Kazuhiko
小鼠成肌细胞C2 C12细胞通常用作研究骨骼肌代谢调节的模型系统。因此，了解C2 C12细胞的代谢特征很重要，我们研究了葡萄糖饥饿对C2 C12肌管自噬的影响。在用高（HG，25.0mM）或低（LG，5.6mM）葡萄糖浓度培养C2 C12肌管后，LG组中的葡萄糖浓度在培养24小时后降低至0 mM，而HG组中的葡萄糖浓度在培养48小时后约为17 mM。LG组的乳酸浓度在24 h时从0增加到约9 mM，然后略有下降，而HG组在48 h时线性增加至21 mM。在LG组中，蛋白质翻译起始的标志物p70 S6激酶的磷酸化显著降低，诱导自噬的标志物LC 3-II/LC 3-I的比率显著升高。LG组GLUT 1和己糖激酶II表达显著升高。总之，培养基中葡萄糖和乳酸盐浓度的这些变化表明C2 C12肌管依赖于无氧糖酵解。我们的研究结果还表明，葡萄糖消耗刺激参与糖酵解的关键分子的表达，细胞自噬也在C2 C12肌管中被激活。
Mouse myoblast C2C12 cells are commonly used as a model system for investigating the metabolic regulation of skeletal muscle. As it is therefore important to understand the metabolic features of C2C12 cells, we examined the effect of glucose starvation on autophagy in C2C12 myotubes. After culture of C2C12 myotubes with high (HG, 25.0 mM) or low (LG, 5.6 mM) glucose concentrations, the concentration of glucose in the LG group had decreased to 0 mm after 24 h of culture and was around 17 mM after 48 h of culture in the HG group. The concentration of lactate increased from 0 to approximately 9 mM at 24 h and then dropped slightly in the LG group, while it increased linearly to 21 mM in the HG group at 48 h. The phosphorylation of p70 S6 kinase, marker for the protein translation initiation was significantly lower and the ratio of LC3-II/LC3-I, marker for the induction of autophagy was significantly higher in the LG group. GLUT1 and hexokinase II expression were significantly higher in the LG group. Together, these changes in glucose and lactate concentrations in the culture media suggest that C2C12 myotubes depend on anaerobic glycolysis. Our findings also suggest that glucose depletion stimulates the expression of key molecules involved in glycolysis and that cellular autophagy is also activated in C2C12 myotubes.