SIRT1 Inhibits Apoptosis by Promoting Autophagic Flux in Human Nucleus Pulposus Cells in the Key Stage of Degeneration via ERK Signal Pathway

Figure 5

SIRT1 promotes autophagy via the ERK, but not AKT, pathway in mildly degenerative NP cells. (a) The levels of p-AKT, AKT, and LC3 II/I proteins were detected by western blot. LY294002 inhibited autophagy (LC3II/I was decreased) by inhibiting p-AKT; however, LV-SIRT1 partly reversed the effect of LY29004002 and promoted autophagy (an increase in LC3II/I expression). (b) The levels of p-ERK1/2, ERK1/2, and LC3II/I proteins were detected by western blot. PD98059 inhibited autophagy (LC3II/I was decreased) by inhibiting p-ERK1/2, and LC3II/I expression did not change after the treatment with LV-SIRT1 combined with PD98059. The relative protein expression of LC3II/I corresponds to the ratio of LC3II signal to LC3I signal, and p-AKT and AKT correspond to the ratio of p-AKT and AKT signals, respectively, to β-actin signal. The values are shown as the of three independent experiments performed in triplicate.

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