Tumor Necrosis Factor Receptor Superfamily Member 12A Enhances Retinal Ganglion Cell Survival and Promotes Axon Regeneration

Regeneration of retinal ganglion cells (RGCs) in adult mammals is highly limited following injury. To uncover transcriptional pathways that enhance this process, we analyzed single-cell transcriptomic profiles of RGCs in mice after optic nerve crush (ONC) and identified potential targets for neuroprotection and axonal regeneration. scRNA-seq revealed that Tumor necrosis factor receptor superfamily member 12A (Tnfrsf12a, also known as Fn14) is enriched in biological processes linked to axonal regeneration in αRGCs/ipRGCs. To validate its neuroprotective and regenerative effects, we engineered an AAV2 viral vector to overexpress Fn14 and assessed its impact in two injury models: ONC and N-methyl-d-aspartate (NMDA)-induced retinal toxicity. Axonal regeneration was evaluated using anterograde cholera toxin subunit B (CTB) labeling, while RGC survival was assessed via RBPMS and β-III tubulin immunostaining, along with electroretinograms (ERG). In the ONC model, CTB tracing confirmed that Fn14 overexpression significantly promotes axonal regeneration, while RBPMS staining demonstrated robust RGC neuroprotection. In the NMDA model, Fn14 overexpression not only prevented NMDA-induced RGC degeneration but also preserved long-range axonal projections and retinal function. Transcriptomic analysis of Fn14-overexpressing retinas in the ONC model further revealed significant downregulation of suppressor of cytokine signaling 3 (Socs3), a finding validated in both injury models. Our study highlights Fn14 as a key regulator of optic nerve injury, capable of enhancing RGC survival and axon regeneration.