Phospholipase iPLA2β averts ferroptosis by eliminating a redox lipid death signal

Ferroptosis, triggered by discoordination of iron, thiols and lipids, leads to the accumulation of 15-hydroperoxy (Hp)-arachidonoyl-phosphatidylethanolamine (15-HpETE-PE), generated by complexes of 15-lipoxygenase (15-LOX) and a scaffold protein, phosphatidylethanolamine (PE)-binding protein (PEBP)1. As the Ca 2+ -independent phospholipase A 2 β (iPLA 2 β, PLA2G6 or PNPLA9 gene) can preferentially hydrolyze peroxidized phospholipids, it may eliminate the ferroptotic 15-HpETE-PE death signal. Here, we demonstrate that by hydrolyzing 15-HpETE-PE, iPLA 2 β averts ferroptosis, whereas its genetic or pharmacological inactivation sensitizes cells to ferroptosis. Given that PLA2G6 mutations relate to neurodegeneration, we examined fibroblasts from a patient with a Parkinson’s disease (PD)-associated mutation (fPD R747W ) and found selectively decreased 15-HpETE-PE-hydrolyzing activity, 15-HpETE-PE accumulation and elevated sensitivity to ferroptosis. CRISPR-Cas9-engineered Pnpla9 R748W/R748W mice exhibited progressive parkinsonian motor deficits and 15-HpETE-PE accumulation. Elevated 15-HpETE-PE levels were also detected in midbrains of rotenone-infused parkinsonian rats and α-synuclein-mutant Snca A53T mice, with decreased iPLA 2 β expression and a PD-relevant phenotype. Thus, iPLA 2 β is a new ferroptosis regulator, and its mutations may be implicated in PD pathogenesis. Ca 2+ -independent phospholipase A 2 β cleaves an oxidized form of phosphatidylethanolamine (PE) involved in ferroptosis such that increases in PE sensitize cells to ferroptosis. A mutant allele of the enzyme links neurodegeneration and ferroptosis.