Abstract
Parkinson disease (PD) is a complex neurodegenerative disorder characterized by a progressive loss of dopaminergic neurons. Mitochondrial dysfunction, oxidative stress or protein misfolding and aggregation may underlie this process. Autophagy is an intracellular catabolic mechanism responsible for protein degradation and recycling of damaged proteins and cytoplasmic organelles. Autophagic dysfunction may hasten the progression of neuronal degeneration. In this study, resveratrol promoted autophagic flux and protected dopaminergic neurons against rotenone-induced apoptosis. In an in vivo PD model, rotenone induced loss of dopaminergic neurons, increased oxidation of mitochondrial proteins and promoted autophagic vesicle development in brain tissue. The natural phytoalexin resveratrol prevented rotenone-induced neuronal apoptosis in vitro, and this pro-survival effect was abolished by an autophagic inhibitor. Although both rotenone and resveratrol promoted LC3-II accumulation, autophagic flux was inhibited by rotenone and augmented by resveratrol. Further, rotenone reduced heme oxygenase-1 (HO-1) expression, whereas resveratrol increased HO-1 expression. Pharmacological inhibition of HO-1 abolished resveratrol-mediated autophagy and neuroprotection. Notably, the effects of a pharmacological inducer of HO-1 were similar to those of resveratrol, and protected against rotenone-induced cell death in an autophagy-dependent manner, validating the hypothesis of HO-1 dependent autophagy in preventing neuronal death in the in vitro PD model. Collectively, our findings suggest that resveratrol induces HO-1 expression and prevents dopaminergic cell death by regulating autophagic flux; thus protecting against rotenone-induced neuronal apoptosis.