PRMT5 Regulates Senescence in Retinal Ganglion Cells by Targeting the Wnt/β-Catenin Signaling Cascade

Purpose: In patients with glaucoma, progressive degeneration of retinal ganglion cells (RGCs) leads to irreversible visual impairments. Despite recent studies indicating that senescence is associated with RGC death, the underlying molecular mechanisms remain unclear.

Methods: The chronic ocular hypertension (COH) mouse model was established by infusing a crosslinking hydrogel into the anterior chamber. Cellular senescence was evaluated using Western blot analysis, cell cycle, senescence-associated β-galactosidase (SA-β-gal) staining, enzyme-linked immunosorbent assay, and immunofluorescence. Functional experiments were conducted in retinal precursor (R28) cells through small interfering RNA-mediated knockdown and plasmid-mediated overexpression. Additionally, the role of the protein arginine methyltransferase 5 (PRMT5)-regulated Wnt/β-catenin pathway in RGC senescence was investigated via intravitreal injection of GSK3326595 and CHIR99021 in mice.

Results: We demonstrate that PRMT5 is markedly downregulated in RGC in a COH mouse model, correlating with increased RGC senescence induced by elevated intraocular pressure. Silencing PRMT5 significantly accelerated senescence, as evidenced by increased SA-β-gal activity, cell cycle arrest, and senescence marker upregulation. Cotreatment with GSK3β inhibitor CHIR99021 alleviated hypoxia-induced senescence and reactivated the Wnt/β-catenin pathway, while the antagonist FH535 negated the neuroprotective effects of PRMT5 overexpression. In vivo, the PRMT5 Inhibitor GSK3326595 reduced RGC survival and heightened senescence markers, whereas CHIR99021 mitigated RGC loss and restored Wnt/β-catenin signaling.

Conclusions: Taken together, these findings highlight the critical role of the PRMT5-regulated Wnt/β-catenin pathway in RGC senescence and neurodegeneration. Targeting this pathway represents a promising therapeutic strategy for glaucoma.