Advanced Glycation End-Products Contribute to Delayed Diabetic Corneal Epithelial Wound Healing via the TLR4...

Diabetic keratopathy (DK) is a significant ocular surface complication of diabetes. This study investigated the role of advanced glycation end-products (AGEs) in DK pathogenesis and the underlying mechanism.

Type I diabetes mellitus (T1DM) mouse model was established by intraperitoneal injection of streptozotocin to assess AGE accumulation and inflammatory factor expression in corneal tissues. A bone marrow-derived dendritic cell (BMDC) culture platform, RNA sequencing (RNA-seq), and pharmacological interventions were used to examine AGE-induced inflammatory response and signaling pathways. The impact of Toll-like receptor 4 (TLR4) signaling (blocked by TAK-242) and AGE formation (inhibited by pyridoxamine [PM]) on diabetic corneal epithelial wound healing (CEWH) was evaluated.

Compared with untreated controls, AGE-challenged BMDCs exhibited an exacerbated inflammatory response and increased phosphorylation of nuclear factor kappa-B (NF-κB) p65 and interferon regulatory factor 3 (IRF3). TLR4 blockade with TAK-242 significantly attenuated this inflammation and reduced phosphorylation of p65 and IRF3. RNA-seq analysis revealed baseline low-grade inflammation and hyper-phosphorylation of p65 and IRF3 in advanced diabetic corneas with AGE accumulation. Topical TAK-242 treatment significantly reversed delayed CEWH and accelerated corneal nerve regeneration in T1DM mice. Similarly, inhibiting AGE formation with PM also expedited diabetic CEWH and nerve regeneration.

The AGE/TLR4 axis drives sustained corneal inflammation by activating p65 and IRF3, thereby promoting DK progression. These findings identify AGE/TLR4 signaling as a potential therapeutic target for DK.