Interferon-γ induces retinal pigment epithelial cell Ferroptosis by a JAK1-2/STAT1/SLC7A11 signaling pathway in Age-related Macular Degeneration

Retinal pigment epithelium (RPE) cell damage is implicated in the pathogenesis of age-related macular degeneration (AMD). An increase of interferon-γ (IFN-γ) levels was observed in patients with AMD, but whether inflammatory factors are causally related to AMD progression is unclear. Here, we demonstrate a direct causal relationship between IFN-γ and RPE cell death. IFN-γ induced human retinal pigment epithelial cell (ARPE-19) death accompanied by increases in Fe²⁺ , Reactive Oxygen Species, lipid peroxidation, and glutathione (GSH) depletion, which are main characteristics of Ferroptosis. Mechanistically, IFN-γ upregulates the level of intracellular Fe²⁺ through inhibiting Fe²⁺ efflux protein SLC40A1 and induces GSH depletion by blocking cystine/glutamate antiporter, System xc-. At the same time, treatment with IFN-γ decreases the level of Glutathione Peroxidase 4 (GPx4), rendering the cells more sensitive to Ferroptosis. JAK1/2 and STAT1 inhibitors could reverse the reduction of SLC7A11, GPx4 and GSH expression induced by IFN-γ, indicating IFN-γ induces ARPE-19 cell Ferroptosis via activation of the JAK1-2/STAT1/SLC7A11 signaling pathway. The above results were largely confirmed in IFN-γ-treated mice in vivo. Finally, we used sodium iodate (NaIO₃ )-induced retinal degeneration to further explore the role of Ferroptosis in AMD in vivo. Consistent with the role of IFN-γ, treatment with NaIO₃ decreased SLC7A11, GPx4 and SLC40A1 expressions. NaIO₃ -induced RPE damage was accompanied by increased iron, lipid peroxidation products (4-hydroxynonenal, malondialdehyde), and GSH depletion, and Ferroptosis inhibitors could reverse the above phenomenon. Taken together, our findings suggest that inhibiting Ferroptosis or reducing IFN-γ may serve as a promising target for AMD.