Single-cell transcriptome and surfaceome profiling of the adult human retinal pigment epithelium.

The retinal pigment epithelium (RPE) is a pigmented monolayer of cells beneath the neural retina that supports photoreceptor cell function essential for vision. Our study explores the diversity of adult human RPE subpopulations and associated implications for retinal biology. Employing cellular indexing of transcriptomes and epitopes by sequencing (CITE-seq), we identified distinct RPE cell subpopulations characterized by unique single-cell transcriptomic and surface protein signatures. Immunohistochemical analysis using CITE-seq markers demonstrated that different RPE subpopulations had previously unappreciated spatial patterns. Enrichment by CITE-seq surface marker selection revealed that different RPE subpopulations have distinct functions. By comparing native RPE cells isolated from the adult RPE layer to cultured RPE cells, we demonstrated that most RPE subpopulations were preserved during culture, a finding with relevance to an RPE cell product currently in clinical trial for treatment of non-exudative age-related macular degeneration. These findings deepen understanding of human RPE biology and provide valuable insights to optimize RPE-cell-based therapy.