Abstract
Purpose :
Retinal Pigment Epithelium (RPE) is monolayer cells between the retina and choroid and has been reported participating in the formation and maintenance of fovea during eye development. However, its diversity and function in foveal and peripheral regions during development are not well understood at single cell level. Therefore, our aims are to elucidate the transcriptomic profiles of the developing human RPE, and to identify transcriptome difference between foveal and peripheral RPE during development.
Methods :
We performed single-nuclei RNA sequencing of RPE cells on foveal and nasal tissue samples collected from 8 human fetus eyes spanning gestational weeks (GW) 10-24 using 10X Chromium Single Cell platform. After data QC, the count profile data were integrated and clustered. Next, downstream analysis was performed to investigate biological signatures.
Results :
We profiled the transcriptome of 106,455 cells and identified 8 sub-cell populations including 74,006 RPE cells across time points. Similar to what is observed in the retina, cells from the foveal region differentiate earlier than cells from the peripheral region. Based on trajectory analysis, pseudo-temporal order was consistent with developmental time in the both foveal RPE (fRPE) and peripheral RPE (pRPE). Cells from fRPE has later pseudotime compared to cells from pPRE from the same eye, suggesting fRPE is more mature than pRPE. Furthermore, it is observed the proportion of progenitor cell is twice higher in the peripheral RPE region than the foveal region. Development process of RPE cells is dynamic as over 1000 differentially expressed genes (DEGs) across pseudo-time are identified. Pathway analysis suggests the DEGs are enriched in cell growth, translation, membrane maintenance, and cholesterol biosynthetic pathways. Another interesting finding is fRPE and pRPE seem to have distinct cell state. Some of 746 DEGs persist to adult RPE such as TFPI2, IGFBP5 and GNGT1 for pRPE, and ID3 and WFCD1 for fRPE, while some known DEGs such as CALCB and CXCL14 were not observed, suggesting the transcriptomic difference between fetal and adult PRE.
Conclusions :
This study provides the comprehensive transcriptome landscape during human fetal RPE development, and distinct lineage map showing RPE maturation difference and distinct gene signature between pRPE and fRPE. Further analysis will be reported.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.