As an essential trace element, iron (Fe) is involved in many important biological processes, but an overexposure can lead to the excessive formation of reactive oxygen and nitrogen species (RONS). An imbalance between RONS and the antioxidative system can result in oxidative stress, cell damage or even cell death. The cell death known as ferroptosis is considered to be Fe-dependent and is discussed in context of glutathione (GSH) deficiency, but little is known about the underlying mechanisms.

To investigate the consequences of Fe overexposure in combination with GSH depletion, we treated the nematode Caenorhabditis elegans (C. elegans) for 24 h with ferric ammonium citrate (FAC) and 2 h or 24 h with diethyl maleate (DEM). This model organism is easy to handle and, due to its numerous mammalian orthologues genes, is suitable for toxicological studies and research on Fe homeostasis. DEM binds to the thiol group of GSH, rendering it non-reductive and unavailable to the antioxidative system. Thus, we have a model with up to five times more total Fe (determined via ICP-OES) and up to only 30 % GSH (determined via LC-MS/MS) compared to untreated control worms. These conditions lead to a reduced survival rate by 20 % and an increase in bound malondialdehyde (determined via LC-FLD), a product of lipid peroxidation. Incubation with FAC, both alone and in combination with DEM, leads to increased phosphatidylethanolamine (PE), but does not alter the phosphatidylcholine (PC) level (determined via SFC-TIMS-MS/MS). Both lipid classes make up the largest proportion of cellular membranes in mammals and C. elegans. These results together with changes in the levels of energy nucleotides (determined via LC-DAD) and lower mitochondrial masses (determined with MitoTracker™ green) indicate that the mitochondria play a crucial role in case of Fe overexposure and GSH depletion.

Since Fe-dependent cell death has been implicated in the pathology of various human diseases, it is necessary to acquire further knowledge about the underlying mechanisms. To identify the pathways involved, further investigations could be carried out at the genetic level via transcriptome analysis.