Fig. 1: Elevated O-GlcNAc-modified protein levels in diabetic retinopathy.

A ELISA analysis of UDP-GlcNAc levels in the vitreous fluid of proliferative diabetic retinopathy (PDR) and non-diabetic patients (n = 7/11 patients). Values are shown as mean ± SEM, with statistical significance at p < 0.0001 (two-tailed Student’s t-test). B Schematic of the streptozotocin (STZ)-induced diabetic model. The upper timeframe represents postnatal weeks, while the lower depicts the duration of diabetes induction by STZ. C Schematic diagram illustrating the oxygen-induced retinopathy (OIR) mouse model. RA: room air. D Western blot and quantification showing elevated O-GlcNAc-modified protein levels in the retina of diabetic mice compared to controls (n = 5/5 mice). Values as mean ± SEM, p = 0.0478 (two-tailed Student’s t-test). E Western blot and quantification showing O-GlcNAc-modified proteins in OIR pups compared to controls (n = 6/6 pups). Values as mean ± SEM, p = 0.046 (two-tailed Student’s t-test). F, G Flat-mounted retinas stained for O-GlcNAc (green) and CD31/IsoB4 (red), illustrating O-GlcNAc levels in control and diabetic/OIR mice. Representative images of O-GlcNAc (green), CD31 (red), and DAPI (blue) staining in frozen eye sections (H) and quantification of O-GlcNAc-modified protein levels in retinal vessels (CD31⁺ area) (I) from diabetic and control mice at different time points (n = 6/5, 6/5, 6/6 mice). Mean ± SEM, p-values < 0.0001 (two-tailed Student’s t-test). Representative images (J) and quantification (K) of O-GlcNAc-modified proteins in retinal vessels (IsoB4⁺ area) from OIR pups and controls (n = 6/6 mice). Mean ± SEM, p = 0.0071 (two-tailed Student’s t-test). L Western blot and quantification of O-GlcNAc-modified proteins in HRCECs exposed to varying glucose concentrations (n = 3 independent experiments). Mean ± SEM, p = 0.0054, p = 0.0007 (one-way ANOVA with Dunnett’s test). M Western blot and quantification of O-GlcNAc-modified proteins in HRCECs under hypoxia for 0, 12, and 24 h (n = 3 independent experiments). Mean ± SEM, p = 0.0051, p = 0.0007 (one-way ANOVA with Dunnett’s test). *p < 0.05; **p < 0.01; ***p < 0.001; scale bars: 100 µm (F, G), 30 µm (H, J). Source data provided as a Source Data file.