Lysosome-associated Membrane Protein-2 Deficiency Increases the Risk of Reactive Oxygen Species-induced Ferroptosis in Retinal Pigment Epithelial Cells

Lysosome-associated membrane protein-2 (LAMP2), is a highly glycosylated lysosomal membrane protein involved in chaperone mediated autophagy. Mutations of LAMP2 cause the classic triad of myopathy, cardiomyopathy and encephalopathy of Danon disease (DD). Additionally, retinopathy has also been observed in young DD patients, leading to vision loss. Emerging evidence show LAMP2-deficiency to be involved in oxidative stress (ROS) but the mechanism remains obscure. In the present study, we found that tert-butyl hydroperoxide or antimycin A induced more cell death in LAMP2 knockdown (LAMP2-KD) than in control ARPE-19 cells. Mechanistically, LAMP2-KD reduced the concentration of cytosolic cysteine, resulting in low glutathione (GSH), inferior antioxidant capability and mitochondrial lipid peroxidation. ROS induced RPE cell death through ferroptosis. Inhibition of glutathione peroxidase 4 (GPx4) increased lethality in LAMP2-KD cells compared to controls. Cysteine and glutamine supplementation restored GSH and prevented ROS-induced cell death of LAMP2-KD RPE cells.