HMOX1 Promotes Ferroptosis Induced by Erastin in Lens Epithelial Cell through Modulates Fe2+ Production

Purpose Ferroptosis is defined by the iron-dependent cell death caused by the accumulation of lipid peroxidation. As a major intracellular Fe pools, heme could be metabolized into ferrous iron, carbon monoxide, and biliverdin by Heme oxygenase-1 (HMOX1). Aged human lens epithelium was reported to highly susceptible to ferroptosis, the functional molecular involved in this progress is not explored. Here, we have demonstrated the function of HMOX1 in human lens epithelium during ferroptotic cell death. Methods HMOX1 stably expressed cell line was constructed by lentivirus transfection. HMOX1 knock-out cell line was constructed by Crispr-cas9 technology. Protein expression was detected by western blot. Inverted microscope was applied to record the morphological changes among different treatments. CCK8 assay and colony formation assay were applied to detect the cell proliferation rate. Cell death was detected by PI staining. Lipid Peroxidation was detected by Cell malondialdehyde (MDA) assay. Intracellular Ferrous and Ferric ions were determined using an iron assay kit. Results HMOX1 expression was induced significantly in HLECs under erastin treatment in a time-dependent and dosage-dependent manner. Forced expression of HMOX1 increase the sensitivity of HLECs to erastin treatment. However, knock-out or knock-down of HMOX1 improved the cell viability of HLECs significantly under erastin treatment. Iron liberated from heme by HMOX1 might play pivotal role to improve the sensitivity of HLECs in response to erastin. Conclusion HMOX1 is an essential pro-ferroptosis enzyme which increase the susceptibility of human lens epithelium to erastin. Ferrous iron, a byproduct of heme, might accelerate erastin triggered ferrotosis cell death in human lens epithelium cells.