Leucine Modulates Mitochondrial Biogenesis and SIRT1-AMPK Signaling in C2C12 Myotubes

Figure 4

Leucine stimulates SIRT1 activity, AMPK phosphorylation, and cellular NAD⁺ in a time-dependent manner. C2C12 myotubes were serum starved overnight and treated with leucine (0.5 mM). Cell lysate was collected and analyzed for cellular SIRT1 activity, western blotting of p-AMPK and cellular NAD⁺ levels at indicated certain time points. (a) SIRT1 activity. (b) Cellular NAD⁺. Both SIRT1 activity and NAD⁺ level were normalized to cellular protein for each sample. (c) Phosphorylation level of AMPK was detected using western blotting following the same time course in C2C12 cells, with resveratrol serving as positive control. Data are mean ± SE (). Different letters indicate significant differences between dark or gray bars. Significantly different from point 0, and significantly different from time point 1.

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