Abstract
Purpose :
The center region of the human retina undergoes prolonged development to enable foveal formation. Many of these processes, ranging from synaptogenesis to cellular migration, begin at the embryonic stage. This study examines the genetic regulation of cell-type specific processes during embryonic foveal development.
Methods :
We combined single-cell RNA-seq and single-cell ATAC-seq to analyze human retinas at fetal weeks (Fwk) 18-19. Foveal center (~1mm in diameter), macula (~2 mm in diameter), and peripheral retina were dissected and dissociated for single-cell transcriptomic and genomic analyses. Single-cell libraries were prepared with 10x Genomics and sequenced with Illumina NovaSeq. Sequencing results were processed using cell ranger and downstream analysis using community single-cell analysis tools and customized scripts.
Results :
We obtained ~64,000 cells from scRNAseq and ~24,000 cells from scATACseq. From the scRNAseq dataset, we identified major cell classes of the retina, including progenitor cells, differentiating cells in transition states, photoreceptors (PR), horizontal cells (HC), bipolar cells (BC), amacrine cells (AC), retina ganglion cells (RGC), Müller glia (MG), microglial and others, in all the three regions. Similar to previous studies, we observed asynchronous development between the central and peripheral retinas: Fovea and macula showed earlier differentiation compared to the peripheral retina as determined by percentages of progenitors and transition cells among regions. Interestingly, we found that cones show gradient enrichment along retinal eccentricity as follows: 98.03% of total PRs in the foveal center, 62.28% in the macula, and 13.09% in the peripheral retina. We further identified cell-type– and region–specific gene expression and functional pathways. We integrated the analysis of gene-expression differences with chromatin accessibility results to map genetic regulatory networks of foveal genes.
Conclusions :
Our study provides a transcriptomic and genomic landscape of embryonic foveal development.
This is a 2021 ARVO Annual Meeting abstract.