Inhibition of STAT1 alleviates oxidative damage in retinal pigment epithelial cells and exhibits neuroprotective effects in autoimmune optic neuritis by upregulating IFI30 lysosomal thiol reductase

Introduction: . Oxidative damage-induced retinal pigment epithelial (RPE) cell Apoptosis and optic nerve inflammation and demyelination are closely related to the pathogenesis of optic neuritis (ON). STAT1 has been found to be activated in the retina and optic nerve of ON rats. Our study aimed to determine whether STAT1 depletion exerts neuroprotective effects against ON in both cellular and animal models.

Material and methods: . ARPE-19 cells were stimulated by H₂O₂ to induce oxidative stress, followed by STAT1 and IFI30 silencing. CCK-8 and flow cytometry assays assessed ARPE-19 cell viability and Apoptosis. RT-qPCR, Western blotting, DCFH-DA staining, and commercial kits detected the levels of STAT1, IFI30, Apoptosis markers, and antioxidant/oxidative markers. CHIP and luciferase reporter assays validated the binding between STAT1 and IFI30 promoter. Female C57BL/6 mice were immunised with myelin oligodendrocyte glycoprotein (MOG) peptide (MOG35-55) to induce experimental autoimmune encephalomyelitis, an animal model of ON. Optic nerve inflammation, demyelination, axonal loss, and retinalganglion cell (RGC) Apoptosis in EAE mice after STAT1 knockdown were evaluated via haematoxylin and eosin, luxol fast blue, immunofluorescence, and Brn3a-TUNEL double staining.

Results: . STAT1 silencing reversed the H₂O₂-induced increase of cell Apoptosis and oxidative stress and the decrease in cell viability in ARPE-19 cells. STAT1 bound with the IFI30 promoter region and negatively regulated its expression. IFI30 knockdown antagonised the protection of STAT1 silencing against H₂O₂-induced oxidative stress and Apoptosis in ARPE-19 cells. STAT1 depletion alleviated optic nerve inflammation, demyelination, axonal loss, and RGC Apoptosis in EAE mice.

Conclusions: . STAT1 silencing exhibits neuroprotective effects against ON by upregulating IFI30.

IFI30; STAT1; apoptosis; inflammation; optic neuritis; oxidative stress; retinal pigment epithelial cells.