SREBP1-driven SCD1 protects retinal pigment epithelium from oxidative damage by activating the NRF2/GPX4 axis

This study reveals the pivotal role of the Sterol Regulatory Element-Binding Protein 1 (SREBP1)/Stearoyl-CoA Desaturase 1 (SCD1) lipid metabolic axis in protecting retinal pigment epithelium (RPE) against oxidative damage. We demonstrate SCD1 downregulation in age-related macular degeneration (AMD) patient tissues and sodium iodate (SI)-induced models, while its overexpression enhances cell viability and ameliorates oxidative injury. Mechanistically, we uncover a novel pathway where SCD1-derived oleic acid activates the nuclear factor erythroid 2-related factor 2 (NRF2)/glutathione peroxidase 4 (GPX4) signaling cascade, scavenging reactive oxygen species (ROS) and suppressing lipid peroxidation. Notably, oleic acid also mitigated oxidative stress via this pathway without directly promoting cell survival. These results not only elucidate SCD1's crucial protective mechanism in AMD pathogenesis but also establish the SREBP1/SCD1 axis as a promising therapeutic target for developing innovative interventions against retinal degeneration.