GPX4 regulates lipid peroxidation and ferroptosis of stored red blood cells

• GPX4 regulates lipid hydroperoxide levels, protecting stored human and mouse RBCs from ferroptosis. • Genetic ablation of Gpx4 or genetic variants common in African donors worsen RBC storage quality and transfusion outcomes. Red blood cell (RBC) membrane lipid peroxidation during blood bank storage profoundly affects transfusion efficacy; however, the genetic determinants underlying RBC resilience remain incompletely defined. Here, we identify a critical role for glutathione peroxidase 4 (GPX4), a pivotal enzyme protecting against iron-dependent lipid peroxidation (ferroptosis), in regulating RBC storage quality and posttransfusion survival. Conditional erythroid-specific deletion of Gpx4 in mice exacerbated lipid hydroperoxide accumulation, oxidation, and ubiquitination of membrane proteins, and reduced RBC recovery after transfusion. Multiomics analyses in 13 091 human blood donors from the Recipient Epidemiology and Donor evaluation Study RBC Omics cohort identified regulatory intergenic (rs8178962), intronic, and missense genetic variants in GPX4 (rs73507255, rs8178967), particularly prevalent among donors of African descent, that were linked to increased lipid peroxidation and compromised posttransfusion hemoglobin increments. Single protein- and metabolome-wide association studies (protein quantitative trait locus/metabolome quantitative trait locus) highlighted genetic variants associated with enhanced (rs8178962) or impaired GPX4 expression, disrupted glutathione homeostasis, lipid hydroperoxide accumulation, accelerated membrane damage, and activation of ferroptotic signatures during RBC storage. These effects were exacerbated by genetic traits impairing redox homeostasis, including glucose 6-phosphate dehydrogenase deficiency (African variant rs1050828 V68M/N126D). Storage of murine RBCs in the presence of the ferroptosis inhibitor ferrostatin-1 prevented storage-induced lipid peroxidation and boosted posttransfusion recovery, a beneficial effect in part phenocopied by supplementation of lipophilic antioxidants vitamin E and Lands cycle fueling via l -carnitine, and in part ablated by GPX4 inhibition via the covalent inhibitor ML210. This study offers mechanistic insights into RBC ferroptosis, and positions GPX4 genetic status as a promising biomarker for precision transfusion medicine.