Abstract
Purpose :
In a new model of fundus camera-delivered light-induced retinal degeneration (FCD-LIRD) we recently demonstrated that the retina could establish a recovery response after sublethal injury. Here, we aimed to analyze the cell-specific transcriptomic changes that occurred in this model and identified cell signaling pathways of interest in the retinal recovery response.
Methods :
Eyes from C57BL/6J mice were collected 4 h, 48h, or 5d after FCD-LIRD and compared to uninjured eyes. Single-cell suspensions of retinal samples were prepared and used to generate libraries using the 10x Genomics platform, which was then sequenced (sc RNA seq). Cell clusters were then identified based on known retinal cell-type specific gene markers. Differential gene expression and pathway analyses of each cluster were performed. Cell clusters and signaling pathways of interest were identified. To further explore the signaling involved in the recovery response, an EphB inhibitor was administered (ip) to mice at 4h after light exposure and then followed by daily injection for seven days. OCT images were taken at baseline and at days 5-, 7- and 10-post injury for retinal thickness analysis.
Results :
Gene expression analysis generated 23 clusters encompassing all known major retinal cell populations. Using unbiased analyses, we identified genes and pathways that were significantly altered in each cell type after light injury, including cellular processes suggestive of activation of pathways for retinal recovery (e.g., synaptogenesis signaling, ephrin receptor signaling, and Reelin signaling in neurons). A subpopulation of Muller glia cells was particularly important in this process. We then found that using an EphB inhibitor significantly exacerbated the level of retinal injury. Finally, we found specific staining for EphB1/B2 of a subpopulation of Muller cells in retinal cross-sections, particularly at day 5 after FCD-LIRD.
Conclusions :
This work identifies acute and subacute cell type-specific responses to retinal photo-oxidative injury. A subpopulation of Muller glia seems to initiate the cellular recovery processes by activating signaling pathways, particularly the ephrin-receptor signaling. A better understanding of these responses may help identify therapeutic approaches to minimize retinal damage and maximize recovery after exposure to injury.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.