Hydroperoxy-lipids Are Essential Yet Insufficient For Execution Of Ferroptosis
Cells with irreparable redox disbalance in membranes trigger a program of regulated death - ferroptosis. 15-lipoxygenase (LOX)-catalyzed accumulation of hydroperoxy-phosphatidyl-ethanolamines (HOO-PEs) has been associated with the execution of ferroptosis; yet, experimental proof of their sufficiency is lacking. Using the Fe-independent hydrophobic radical initiator, 2,2'-azobis(2,4-dimethyl)-valeronitrile (AMVN), we demonstrate that the accumulation of hydroperoxy-phospholipids (HOO-PLs) is necessary, but insufficient for driving ferroptosis. We further show that Fe-catalyzed decomposition of HOO-PLs into radical intermediates and oxidatively truncated (OxTr) electrophilic species, as well as the formation of protein adducts with OxTr electrophilic species are required for the completion of the ferroptotic program. Consequently, three types of agents - inhibitors of LOXs and other enzymatic generators of HOO-PLs, radical scavengers, and small-molecule nucleophiles - acting at different stages of lipid peroxidation during the ferroptotic program represent effective and specific ferroptosis regulators and potential therapeutic remedies.