Antimony-induced hippocampal neuronal impairment through ferroptosis activation from NCOA4-mediated ferritinophagy

Recently, our group identified antimony (Sb) as a novel nerve pollutant, can lead to neuronal injure. However, Sb-associated neurotoxicological mechanisms yet remain unclear. Herein, we found Sb induced hippocampal neuronal ferroptosis in vivo and in vitro. Moreover, ferroptosis inhibition using ferrostatin-1 effectively attenuated Sb-induced neuronal damage in PC12 cells and mice hippocampal regions. Furthermore, iron chelator deferoxamine (DFO) also effectively attenuated ferroptosis and cytotoxicity in PC12 cells. In vitro, Sb treatment reduced expression of the heavy (H)- and light (L)-chain subunits of ferritin (FTH1 and FTL). Moreover, Sb accelerated FTH1 and FTL protein degradation, while ferritin overexpression by plasmid or hippocampal AAV injections dramatically weaken Sb-induced ferroptosis. Sb exposure accelerated autophagic flux, and autophagy inhibition with beclin1 knockdown effectively reduced Sb-mediated ferroptosis. 3-methyladenine treatment in Sb-exposed mice prevented the decrease of FTH1 and FTL protein, resulting in recovery of Sb-induced hippocampal ferroptosis as well as neuronal loss, suggesting that Sb triggered hippocampal neuronal ferritinophagy. Finally, we found Sb upregulated NCOA4 protein expression, while NCOA4 knockdown significantly attenuated Sb-triggered ferroptosis. Collectively, our results proved that Sb triggers hippocampal neuronal ferroptosis through NCOA4-dependent ferritinophagy.