Nerve Growth Factor Protects Against Alcohol-Induced Neurotoxicity in PC12 Cells via PI3K/Akt/mTOR Pathway

Aims: To study whether autophagy participates in the neuroprotective effect of nerve growth factor (NGF) on neurons treated with alcohol. Methods: The autophagy-related markers were used to explore the role of autophagy in PC12 cells exposed to alcohol or pre-incubated with NGF before initiating the treatment with alcohol (100 mM; 6 h). PC12 cells were pre-incubated with 3-methyladenine (3-MA) (10 mM; 1 h) or rapamycin (100 nM; 1 h) before co-incubated with alcohol (100 mM; 6 h) in order to investigate the relationship between apoptosis and autophagy. PC12 cells were pre-incubated with LY294002 (50 mu M; 30 min) before co-incubated with NGF and alcohol in order to analyze the protein expression of PI3K/Akt/mTOR pathway via western blotting. Result: By methylthiazoltetrazolium, western blotting and flow cytometry assays, we found that cell viability decreased in a dose-and time-dependent manner after treatment with alcohol in PC12 cells. As cells were exposed to alcohol, the levels of LC3-II proteins became elevated, likewise, pretreatment with 3-methyladenine (3-MA, an autophagic inhibitor) or rapamycin (an autophagic inducer) resulted in an increased or decreased percentage of apoptosis in contrast to other alcoholtreated groups, respectively. NGF markedly increased LC3-II production after treatment with alcohol in a dose-dependent manner. Moreover, NGF remarkably attenuated the phosphorylation effect of alcohol exposure on PI3K/Akt/mTOR pathway, which was suppressed by LY294002 (Akt inhibitor). Conclusions: NGF protects against alcohol-induced neurotoxicity via PI3K/Akt/mTOR pathway. Short summary: In this study, we chose the PC12 cell line as a neuronal model, and our results demonstrate that nerve growth factor can induce autophagy with the neuroprotective effect and regulatory mechanisms of alcohol-induced autophagy in PC12 cells.