(W1132) Differential effects of mononuclear phagocytes from healthy Individuals and age-related macular degeneration patients on the transcriptome of hESC-derived retinal pigment epithelium cells.
Purpose: Reticular pseudodrusen (RPD) are present in a subset of individuals with age-related macular degeneration (AMD) and are associated with an increased progression risk to late AMD. The underlying mechanisms for this association remain unclear. This study evaluated whether peripheral blood mononuclear cells (PBMCs) from individuals with intermediate AMD and RPD (iAMD/RPD+) uniquely influenced the transcriptome of retinal pigment epithelium (RPE) cells compared to PBMCs from individuals with iAMD without RPD (iAMD/RPD-) or healthy controls.
Methods: PBMCs were collected from patients with iAMD/RPD+ (N=9), those with iAMD/RPD- (N=9), and age-matched healthy controls (N=9). H9 human embryonic stem cells were differentiated into RPE cells and cultured for 90 days. CD14+ monocytes were enriched from PBMC samples and co-cultured with RPE cells for 24 hours. Following co-culture, monocytes were removed, and total RNA was extracted from the RPE for bulk RNA sequencing (Illumina NovaSeq 6000). Transcriptomic data were normalised to adjust for any adherent immune cells and analysed using gene set enrichment analysis.
Results: Co-culturing RPE cells with PBMCs from healthy controls, compared to untreated RPE cells, resulted in 5015 differentially regulated genes (FDR < 0.05), including 12 genes critical for retinoid metabolism and RPE function. Co-culturing RPE cells with PBMCs from individuals with iAMD/RPD+ or iAMD/RPD- showed significant enrichment of gene sets related to inflammation compared to healthy controls, including those involved in chemotaxis (CXCL1, IL6, ICAM1), and cytokine/chemokine production. Finally, co-culturing RPE with PBMCs from iAMD/RPD+ resulted in distinct gene set enrichment differences compared to iAMD/RPD-, including negative enrichment for genes involved in epithelial mesenchymal transition.
Conclusions: Our results suggest that PBMCs from individuals with iAMD induce molecular changes in the RPE. Furthermore, PBMCs from individuals with iAMD and RPD influence the RPE in a distinct manner compared to iAMD patients without RPD. These data implicate circulating innate immune cells in influencing the RPE transcriptome, causing differential RPE dysfunction between AMD patients with and without RPD.
