Diabetic retinopathy (DR), a leading cause of vision loss in diabetes, is driven by basement membrane (BM) thickening and vascular hyperpermeability. While glucagon-like peptide-1 receptor agonists (GLP-1RAs) like semaglutide exhibit pleiotropic benefits, their retinal effects remain controversial. This study investigates the mechanistic role of semaglutide in mitigating DR pathogenesis, focusing on Annexin A2 (AnxA2) and its interplay with BM remodeling.

A high-fat diet/streptozotocin-induced type 2 diabetic mouse model was established. Retinal histopathology, vascular permeability (FITC-dextran), and ultrastructure (transmission electron microscopy) were evaluated. Integrated proteomics and single-cell RNA sequencing identified AnxA2 as a key regulator. Endothelial-specific AnxA2 overexpression via adeno-associated virus (AAV) and functional assays (Western blot, immunofluorescence and immunohistochemistry) elucidated its role in MMP-9 activation and BM degradation.

Diabetic mice exhibited retinal degeneration, BM thickening (P < 0.05), and elevated vascular leakage (P < 0.001). Semaglutide, but not insulin, reversed these pathologies by restoring AnxA2 expression in retinal endothelial cells (P < 0.05), thereby enhancing MMP-9 activity (P < 0.05) and collagen-IV degradation. Single-cell transcriptomics confirmed AnxA2 downregulation in diabetic endothelial cells (P = 0.027), which was rescued by semaglutide (P = 0.012). AAV-mediated AnxA2 overexpression normalized BM thickness (P < 0.001) and reduced fluorescein leakage (P < 0.001), demonstrating its critical role in MMP-9-dependent ECM homeostasis.

Semaglutide ameliorates diabetic retinal degeneration by upregulating endothelial AnxA2, which activates MMP-9 to degrade pathologically thickened BM and ameliorates retinal vascular permeability destruction. These findings unveil a glucose-independent vascular protection of semaglutide in diabetic retinopathy, positioning AnxA2 as a therapeutic target for early DR intervention.