Senescence-induced endothelial-to-mesenchymal transition accelerates the subretinal fibrosis in neovascualr age-related macular degeneration.

BACKGROUND

Subretinal fibrosis remains the severe vision loss in neovascular age-related macular degeneration (nAMD), yet effective treatments are still deficient. Cellular senescence and endothelial-to-mesenchymal transition (EndMT) have been implicated in nAMD pathogenesis.

METHODS

We analyzed single-cell RNA sequencing data to investigate the role of senescent choriocapillary endothelial cells (CapECs) in subretinal fibrosis. In vitro assays were performed to validate the link between senescence and EndMT. We utilized Brown-Norway rats and INK-ATTAC mice with laser-induced subretinal fibrosis to evaluate the therapeutic effects of senolytic treatment (dasatinib plus quercetin, D + Q) or selective clearance of p16INK4A-positive cells. Additionally, young (2-3 months) and old (18 months) C57BL/6J mice were compared to assess the influence of aging on EndMT and fibrosis.

RESULTS

Our results revealed that CapECs in nAMD exhibited elevated SenMayo gene set variation analysis (GSVA) scores, and upregulated differentially expressed genes (DEGs) were enriched in senescence and mesenchymal transition pathways. A higher proportion of senescence-like CapECs (17.68%) was observed in nAMD, which also showed increased mesenchymal scores and TGFB1 expression. Senescent endothelial cells in laser-induced fibrotic models and bleomycin/doxorubicin-treated human umbilical vein endothelial cells underwent enhanced EndMT. Early intervention with D + Q or removal of p16INK4A-positive cells markedly reduced subretinal fibrosis and restored retinal function. Furthermore, endothelial cells from old mice exhibited heightened EndMT and more severe subretinal fibrosis compared to those from young mice.

CONCLUSIONS

The accumulation of senescent endothelial cells promotes subretinal fibrosis via EndMT in nAMD. Targeting these cells represents a promising therapeutic strategy for mitigating fibrosis-associated vision loss.