Targeting endoplasmic reticulum stress in diabetic retinopathy: mechanistic insights and emerging therapies

PURPOSE: To summarize the role of endoplasmic reticulum stress (ERS) in the pathogenesis of diabetic retinopathy (DR) and evaluate potential ERS-targeted interventions. METHODS: This review analyzes recent preclinical and clinical studies focusing on the molecular mechanisms of ERS and its impact on retinal inflammation, oxidative stress, and angiogenesis in DR. RESULTS: ERS, triggered by hyperglycemia-induced oxidative stress and glucotoxicity, activates the unfolded protein response (UPR) via inositol-requiring enzyme 1 (IRE1), PKR-like endoplasmic reticulum kinase (PERK), and activating transcription factor 6 (ATF6) pathways. While initially protective, prolonged ERS leads to apoptosis, chronic inflammation, and neovascularization. Key downstream mediators include C/EBP homologous protein (CHOP), X-box binding protein 1 (XBP1), and activating transcription factor 4 (ATF4). ERS inhibitors such as 4-phenylbutyric acid and tauroursodeoxycholic acid, along with selective modulators of UPR signaling, have shown neuroprotective and anti-inflammatory effects in DR models. Combination therapies integrating antioxidants and anti-inflammatory agents demonstrate synergistic efficacy. However, clinical translation remains limited by delivery barriers and incomplete understanding of UPR-specific actions in the human retina. CONCLUSION: Targeting ERS presents a promising therapeutic strategy for DR, with the potential to preserve vision and improve outcomes for diabetic patients. Future research should focus on elucidating the precise molecular pathways and developing targeted, personalized ERS-modulating therapies.