Ferritin confers protection against iron-mediated neurotoxicity and ferroptosis through iron chelating mechanisms in MPP+-induced MES23.5 dopaminergic cells

Ferritin is the main iron storage protein and plays an important role in maintaining iron homeostasis. In a previous study, we reported that apoferritin exerted a neuroprotective effect against MPTP by regulation of brain iron metabolism and ferroptosis. However, the precise cellular mechanisms of extracellular ferritin underlying this protection are not fully elucidated. Ferritin was reported to be localized in different intracellular compartments, cytoplasm or released outside cells. Here we demonstrated that the intracellular iron increased after iron treatment in primary cultured astrocytes. These iron-loaded astrocytes released more ferritin in order to buffer extracellular iron. Using co-culture system of primary cultured astrocytes and MES23.5 dopaminergic cells, we showed that ferritin released by astrocytes could enter MES23.5 dopaminergic cells. And primary cultured astrocytes protected MES23.5 dopaminergic cells against 1-methyl-4-phenylpyridinium ion (MPP+)-induced neurotoxicity and ferroptosis. In addition, we found that exogenous Apoferritin or Ferritin pretreatment could significantly inhibit MPP+-induced cell damage by restoring the cell viability and mitochondrial transmembrane potential (ΔΨm). Furthermore, exogenous Apoferritin and Ferritin might also protect MES23.5 dopaminergic cells against MPP+ by decreasing reactive oxygen species (ROS) and inhibiting the increase of the labile iron pool (LIP). This suggests that astrocytes increased ferritin release to respond to iron overload, which might inhibit iron-mediated oxidative damage and ferroptosis of dopamine (DA) neurons in Parkinson's disease (PD).