Rotenone induces ferroptosis and neurotoxicity through inhibition of SIRT1-Nrf2-ferroportin 1/GPX4 pathways in SH-SY5Y cells and mice

Rotenone is a pesticide that causes damage to dopaminergic neurons and contributes to Parkinson's disease (PD) with prolonged exposure. Recent evidence suggested that ferroptosis contributes to rotenone-induced dopaminergic neurotoxicity. However, the underlying mechanisms remain unclear. SIRT1 and downstream nuclear factor Nrf2 play critical roles in regulating cell survival in pathological conditions. In this stidu, we revealed the role of SIRT1-Nrf2 axis in rotenone-induced neuron ferroptosis. Results showed that in SH-SY5Y cells, rotenone exposure decreased cell viability, which was associated with iron accumulation, lipid peroxidation, glutathione depletion and alterations of ferroptosis-related markers. Ferrostatin-1 and lipostain-1, prevented rotenone-induced neuronal damage as iron chelator and ferroptosis inhibitor, respectively. Furthermore, rotenone treatment blocked the expression and activation of SIRT1-Nrf2 axis and promoted their degradation through proteasome and lysosome. Agonists of SIRT1 and Nrf2 mitigated rotenone-induced iron accumulation, thereby reducing lipid peroxidation and neuron ferroptosis. Mechanistically, the expression of ferroportin 1 (Fpn-1) and glutathione peroxidase 4 (GPX4) was up-regulated by the activation of the SIRT1-Nrf2 axis, which in turn inhibited rotenone-induced iron accumulation and lipid peroxidation responses in cells, respectively. VIT-2763 and RSL4, the inhibitors of Fpn-1 and GPX4, counteracted the protective effects of SIRT1-Nrf2 axis against rotenone-induced ferroptosis. Finally, we revealed reduced expression of SIRT1-Nrf2 axis in rotenone-treated mice and activation SIRT1-Nrf2 by agonists ameliorated rotenone-induced ferroptosis of dopaminergic neuron and improved gait abnormality in mice. Taken together, we revealed that rotenone induced neuron ferroptosis through iron accumulation and lipid peroxidation via inhibition of SIRT1-Nrf2 axis, providing additional evidence for the mechanisms of pesticide-induced neurotoxicity and related PD.