POU4F1 and optic neuritis: Permanent visual decline in optic neuritis coincides with the loss of RGCs.7 Retinas from each treatment group were isolated and stained with antibodies directed against Brn3a, a marker of RGCs, to determine whether SIRT1 or NRF2 gene augmentation conferred a protective advantage upon RGCs during EAE (Fig. 5).