Abstract
Purpose :
Several previous studies have investigated therapeutic effects of exosomes derived from many different cell type on retinal ganglion survival in optic nerve injury models. Howevere, there has been no study investigating the therapeutic effects of three-dimensional (3D) retinal organoid (RO) derived exosomes (Exo-ROs) on RGC survival, especially in chronic ocular hypertensive model. This study aims to investigate the therapeutic effects of Exo-ROs on RGC survival in a chronic ocular hypertensive (COH) rat model.
Methods :
3D ROs were formed from hiPSC-derived aggregates. We collected RO-conditioned medium at day 60 of RO differentiation to isolated exosomes released from ROs. COH model was achieved by conducting circumlimbal suture in Spraque-Dawley rats. Intravitreal injection of Exo-ROs was performed immediately after the suture placement. BRN-3a+ cell counting was perfomred in retinal whole-mounts. Exosomal RNA seq profiling was conducted to analyze miRNA content in Exo-ROs. Expression of targeting signaling pathway were assessed by both Western Blot analysis and immunohistochemistry after Exo-RO treatment.
Results :
Exo-ROs were successfully extracted from RO-conditioned medium, which expressed exosomal markers CD9, CD63, and CD81. Intravitreal injection of Exo-ROs resulted in significantly enhanced RGC survival compared to vehicle injected COH eyes (p < 0.001). Exosomal RNA seq profiling revealed the genes in Exo-ROs were mainly involved in MAPK signaling pathway. Western blot analysis and immunohistochemistry for MAPK family members showed significant decrease in Exo-RO-treated COH eyes compared to vehicle-treated COH eyes, suggesting that Exo-ROs rescue RGCs in COH through inhibition of MAPK pathway.
Conclusions :
The results of our study showed neuroprotective effects of Exo-ROs on RGCs in a rat model of COH. This pro-survival effects of Exo-ROs on RGCs seem to be mainly achieved by inhibiting MAPK pathway.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.