Role of High‐mobility group box‐1 in diabetic retinal vasculopathy and neuropathy

Abstract

SummaryHigh‐mobility mobility group box‐1 (HMGB1) is a non‐histone DNA‐binding protein that plays an important role in chromatin organization and transcriptional regulation. Extracellular HMGB1 functions as a proinflammatory cytokine and triggers the inflammatory response through the activation of multiple receptors such as the receptor for advanced glycation end products (RAGE), toll‐like receptor‐2 (TLR2), TLR4 and TLR9. We demonstrated that HMGB1 and RAGE were expressed in fibrovascular epiretinal membranes from patients with proliferative diabetic retinopathy (PDR). In addition, we demonstrated increased levels of HMGB1 in the vitreous samples from patients with PDR and that there were significant positive correlations between the vitreous levels and HMGB1 and the levels of the biomarkers of inflammation and oxidative injury. Furthermore, we demonstrated that diabetes induced significant upregulation of the expression of HMGB1 and RAGE in the retinas of rats and mice and that HMGB1 mediates diabetes‐induced oxidative stress, activation of inflammatory signaling pathways, breakdown of the blood‐retinal barrier and neuropathy in the retina. Therefore, compounds inhibiting HMGB1 may be novel therapeutic agents for diabetic retinopathy.