Purpose: The purpose of this study was to investigate the protective effect of low-dose trans-resveratrol (trans-RSV) on diabetes-induced retinal ganglion cell (RGC) degeneration and its possible mechanism.
Methods: A streptozotocin-induced diabetic mouse model was established and treated with or without trans-RSV intragastric administration (10 mg/kg body weight/day) for 12 weeks. Oscillatory potentials (Ops) of the dark-adapted electroretinogram (ERG) were recorded. The number of RGCs was detected by Tuj1 and TUNEL staining. The apoptosis markers in the retina were analyzed by Western blot. The cross sections of optic nerves were observed by transmission electron microscopy. In addition, mouse neuroblastoma N2a cells were injured by high-glucose (HG) treatment. Cell viability and apoptosis were measured with or without low-dose trans-RSV treatment. The intracellular localization of tyrosyl transfer-RNA synthetase (TyrRS) was observed in both mouse retinas and N2a cells. The effects of low-dose trans-RSV on the binding of TyrRS to the transcription factor c-Jun and the binding of c-Jun to pro-apoptotic genes were analyzed by co-IP and ChIP assays in HEK 293 cells.
Results: Trans-RSV relieved electrophysiological injury of retinas and inhibited RGC apoptosis in diabetic mice. It also protected N2a cells from HG-induced apoptosis. Additionally, it promoted TyrRS nuclear translocation in both diabetic mouse retinas and HG-treated N2a cells. Trans-RSV promoted TyrRS binding to c-Jun, inhibited the phosphorylation of Ser-63 of c-Jun, and downregulated pro-apoptotic gene transcription.
Conclusions: Low-dose trans-RSV can ameliorate diabetes-induced RGC degeneration via the TyrRS/c-Jun pathway. It can promote TyrRS nuclear translocation and bind to c-Jun, downregulating c-Jun phosphorylation and downstream pro-apoptotic genes.