Mitochondrial mechanisms in ferroptotic death of SH-SY5Y cells induced by erastin and ferric ammonium citrate

Ferroptosis has been characterized over the last few years as a form of iron-dependent regulated cell death which is accompanied by an accumulation of reactive oxygen species and lipid oxidation products inside the cells along with typical morphological alterations in mitochondria. Ferroptosis is inhibited by specific inhibitors called ferrostatin-1 and liproxstatin-1, apart from iron-chelators and several antioxidants, and the process is implicated in multiple pathological conditions. There are, however, certain ambiguities about ferroptosis, especially with regard to the involvement of mitochondria in the final execution of ferroptotic death. This study uses two typical inducers of ferroptosis such as erastin and ferric ammonium citrate on SH-SY5Y cells, and shows clearly that ferroptotic death of cells is accompanied by the loss of mitochondrial membrane potential and intracellular ATP content along with an accumulation of reactive oxygen species and malondialdehyde as well as a depletion of reduced glutathione. All these are prevented by ferrostatin-1 and liproxstatin-1. Additionally, cyclosporine A prevents mitochondrial alterations and cell death induced by erastin or ferric ammonium citrate, implying the crucial role of mitochondrial permeability transition pore activation in ferroptotic death. Under our experimental conditions, it is also observed that the late-phase production of reactive oxygen species is inhibited by cyclosporine A.