Ferroptosis Contributes to Retinal Ganglion Cell Loss in GLAST Knockout Mouse Model of Normal Tension Glaucoma.

PURPOSE: Visual impairment from normal-tension glaucoma (NTG) poses an increasing burden, yet the underlying mechanism remains unclear. Investigating protective mechanisms for NTG is critical. We aimed to investigate the role of ferroptosis in retinal ganglion cell (RGC) damage in glutamate-aspartate transporter (GLAST) knockout (GLAST-/-) mice, a model for NTG, and also to determine whether inhibiting ferroptosis can provide neuroprotection.

METHODS

GLAST-/- mice and a glutamate-induced excitotoxicity model in primary RGCs were used to investigate retinal and RGC damage. RNA sequencing identified ferroptosis-related pathways in GLAST-/- retinas. Oxidative stress, lipid peroxidation, and ferroptosis activation were assessed using western blotting and immunofluorescence. Immunohistochemistry (IHC) assessed lipid peroxidation and ferroptosis activation in human retinal tissue. Ferrostatin-1 (Fer-1) was administered to evaluate its neuroprotective effects on RGC survival, retinal thickness, and visual function.

RESULTS

RNA sequencing revealed significant enrichment of ferroptosis-related pathways in GLAST-/- retinas. Both GLAST deletion and glutamate-induced excitotoxicity increased oxidative stress, lipid peroxidation, and ferroptosis activation in RGCs. IHC in human retinas confirmed elevated 4-hydroxynonenal (4-HNE) and acyl-coenzyme A synthetase long-chain family member 4 (ACSL4) expression. Furthermore, Fer-1 treatment significantly reduced lipid peroxidation, thereby attenuating the ferroptosis pathways. This intervention ameliorated RGC loss associated with GLAST deletion, protected retinal structure and thickness, and improved amplitudes of the photopic negative response, a-wave, b-wave, and oscillatory potentials.

CONCLUSIONS

Ferroptosis significantly contributes to RGC and retinal damage in the GLAST-deletion NTG model. Inhibiting ferroptosis with Fer-1 presents a promising therapeutic strategy for protecting visual function in NTG.