Integrin β3 Promotes Retinal Neovascularization via Endoplasmic Reticulum Stress-Mediated Endothelial Cell Senescence

Purpose: Integrin β3 (ITGB3/Itgb3), a transmembrane receptor implicated in cell adhesion and signaling, may regulate cellular senescence. We hypothesized that ITGB3 drives retinal neovascularization (RNV) through endoplasmic reticulum stress (ERS)-mediated endothelial cell (EC) senescence and aimed to delineate the underlying molecular mechanisms. Methods: Retinal vascular EC subpopulations were profiled by single-cell RNA sequencing (scRNA-seq) in an oxygen-induced retinopathy (OIR) model. Immunofluorescence staining further confirmed P21 and Integrin β3 expression. Human retinal microvascular endothelial cells (HRMECs) were transfected with ITGB3 small interfering RNA (siRNA), and cell migration, proliferation, and tube formation were assessed. Cellular senescence was evaluated by SA-β-Gal staining together with enzyme-linked immunosorbent assay and Western blot analysis of senescence markers (p21, PAI-1) and senescence-associated secretory phenotype (SASP) factors. Protein expression of PERK/eIF2α/ATF4 ERS pathway were also examined. Results: ScRNA-seq in the OIR model identified a retinal vascular EC subpopulation associated with cellular senescence and ERS, and Itgb3 expression in ECs was significantly upregulated in the OIR model. Immunofluorescence staining confirmed a marked increase in EC senescence and a specific upregulation of integrin β3 colocalized with ECs in OIR retinas. In vitro, ITGB3 knockdown suppressed HRMEC migration, proliferation, and tube formation. Furthermore, ITGB3 knockdown also attenuated hypoxia-induced activation of the PERK/eIF2α/ATF4 pathway and reduced senescence features, including SA-β-Gal positivity, and the expression of p21, PAI-1, and SASP factors. Conclusions: ITGB3 drives RNV by promoting ERS-mediated EC senescence through activation of the PERK/eIF2α/ATF4 pathway. Targeting this signaling axis may represent a potential therapeutic strategy for RNV.