Role of Aldehyde Dehydrogenase 2 in 1-Methy-4-Phenylpyridinium Ion-Induced Aldehyde Stress and Cytotoxicity in PC12 Cells

Aldehyde stress contributes to molecular mechanisms of cell death and the pathogenesis of Parkinson’s disease (PD). The neurotoxin 1-Methy-4-Phenylpyridinium Ion (MPP⁺) is commonly used to model PD. Aldehyde dehydrogenase 2 (ALDH₂) is an important enzyme detoxifying aldehydes. The aim of this study is to evaluate whether MPP⁺-induced neurotoxicity is involved in aldehyde stress by modulation of ALDH₂. Our results demonstrated that treatment of PC12 cells with MPP⁺ leads to aldehyde stress by increasing in loads of malondialdehyde and 4-hydroxynonenal, which indicated that MPP⁺-induced aldehyde stress contributes to its cytotoxicity in PC12 cells. We also showed that MPP⁺ up-regulates the expression and activity of ALDH₂ in PC12 cells and that inhibition of ALDH₂ by its specific inhibitor daidzin prevents MPP⁺-induced decrease in cell viability and increases in apoptosis, oxidative stress and aldehyde stress in PC12 cells. These findings suggest that aldehyde stress contributes to MPP⁺-induced toxicity in PC12 cells by upregulation of ALDH₂. This study provides a novel insight into the role of ALDH₂ in the neurotoxicity of MPP⁺.