Single-cell RNA sequencing identifies age-related transcriptomic changes of human choriocapillaris endothelial cells and pericytes.

Abstract

Purpose : The choroid is a heterogenous tissue that supports retinal physiology. Within the choroid, the dense choriocapillaris vascular network supplies photoreceptor cells with the majority of their oxygen and glucose. However, the aging choriocapillaris undergoes molecular changes implicated in age-related macular degeneration pathogenesis. We set out to identify age-related transcriptomic changes specific to the choriocapillaris and other choroidal cells using single-cell RNA sequencing of human donor choroids.

Methods : Central retinal pigment epithelium/choroidal tissue from 2 infant (ages 1 and 8 months) and 6 adult (ages 61-92) human donor eyes was dissociated in collagenase and cryopreserved. Thawed cells were enriched for CD31-expressing endothelial cells before single-cell RNA sequencing. Resulting reads were mapped to the human genome with CellRanger and analyzed with the Seurat R package.

Results : A total of 41,494 cells were recovered, and clusters corresponding to all choroidal cell types were identified. Endothelial cells (n = 12,062) segregated into distinct arterial, choriocapillaris, and venous clusters (Figure 1). Infant choriocapillaris was specifically enriched for genes that transcriptionally regulate angiogenesis, including ID3, SOST, and KLF2. In addition, the expression of several surface adhesion molecules changed in the choriocapillaris with age. VCAM1, MCAM and ICAM1, which promote leukocyte adhesion to the vascular endothelium, were enriched in adult choriocapillaris while CD34, which inhibits leukocyte adhesion, was enriched in infant choriocapillaris. Distinct clusters of pericytes (which surround the choriocapillaris) and smooth muscle cells (which surround large caliber vessels) were identified. Pericytes expressed more complement factor H (CFH) compared to smooth muscle cells (logFC = 1.32), and the largest contributor of CFH expression in adult cell types was pericytes.

Conclusions : Single-cell RNA sequencing can resolve the transcriptional heterogeneity within the choroid into distinct cell populations. Using this methodology, we observed that the transcriptome of the choriocapillaris and their interfacing pericytes changes with age. Adult choriocapillaris is enriched in pro-inflammatory adhesion molecules and adult pericytes produce the most CFH of all choroidal cell types.

This is a 2020 ARVO Annual Meeting abstract.

 

Single-cell RNA sequencing of 8 human donor choroids.