Abstract
Purpose :
Most vision loss diseases are a result of age-related retinal degeneration. Aging is progressive process that occurs in all cells leading to dysfunction. It is essential to understand the molecular mechanisms that regulate retinal aging with single cell resolution to identify targets and develop therapeutics to slow or prevent the onset of these degenerative diseases. Therefore, we conducted a comprehensive transcriptomic and epigenomic analysis of cellular aging in the retina in order to identify tissue specific and cell-type specific Gene Regulatory Networks that mediate progressive aging in the retina.
Methods :
We performed combined single cell RNA (scRNA) and single cell ATAC (scATAC)-sequencing on whole retinas from mice aged 5wk, 12wk, 17wk, 32wk, 49wk, 68wk, 91wk, 106-108wk, and 120wk using the 10X Genomics Multiome platform. Two multiomic libraries were generated for each timepoint, and each library contains retinas from 2 male and 2 female C57BL/6J mice. To test if acute damage alters the rate of cellular aging, we generated multiomic libraries 4h, 10h, 24h, 48h, 72h, 96h, 14d, 2mo, and 6mo following intravitreal injection of 2ul of 100mM NMDA. Additional multiomic libraries were generated from mice exposed to cigarette smoke for 5hrs/d 5d/wk for 2mo, 6mo, or 2mo followed by 2mo recovery.
Results :
Using the scRNA-seq data we were able to train linear regression models capable of accurately predicting transcriptomic age. We found that following acute NMDA injury or smoke exposure transcriptomic age of cells was accelerated relative to chronological age of the animal. We found photoreceptor cells and Muller glia show the greatest age-related shift in transcriptomic and epigenomic profile relative to other retinal cells. By identifying enriched motifs in differentially accessible regions between younger and older animals, and identifying differentially expressed transcription factors across age, we have been able to identify age-related Gene Regulatory Networks.
Conclusions :
We find that there are distinct age-related, cell-type specific changes in gene expression profiles and epigenomic landscape across age, and that acute damage activates similar processes. These findings are important for identifying targets for the development of therapeutics to intervene with aging and potentially induce rejuvenation.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.