Rotenone has recently been widely used to establish Parkinson's disease (PD) models to replicate the features of PD. However, the mechanisms involved in rotenone neurotoxicity have not been elucidated. The aim of the present study was to identify the neurotoxicity of rotenone through intraperitoneal injection in mice and to investigate the global changes of phosphorylation proteomic profiles in rotenone-injured SH-SY5Y cells through a label-free proteomic analysis using a PTMScan with LC-MS/MS. ICR (Institute of Cancer Research) mice were intraperitoneally injected with different dosages of rotenone (1 mg/kg/d or 3 mg/kg/d) daily for 21 consecutive days. Rotenone caused a dose-dependent decrease in locomotor activities and a decrease in the number of Nissl-positive and tyrosine hydroxylase (TH)-immunoreactive neurons in the substantia nigra pars compacta (SNpc). Here, 194 phosphopeptides on 174 proteins were detected in SH-SY5Y cells, and 37 phosphosites on 33 proteins displayed statistically significant changes in expression after rotenone injury. The downregulation of phosphorylated Akt and mTOR was further confirmed by western blot analysis. A specific Akt activator, SC79, could protect cell viability and induce autophagy in rotenone-injured SH-SY5Y cells. This study indicates the involvement of the Akt/mTOR (mammalian target of rapamycin) signaling pathway in rotenone-injured SH-SY5Y cells and provides molecular information for the neurotoxicity of rotenone.
Keywords: Akt; Parkinson’s disease; mTOR; neurotoxicity; rotenone.