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Huey Cai, Jie Gong, Lawrence J Rizzolo, Lucian V Del Priore, Mark Anthony Fields; Altered Gene Expression Profile in iPSC-derived RPE Cells from AMD Patients. Invest. Ophthalmol. Vis. Sci. 2020;61(7):2276.
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Dysfunction of retinal pigment epithelial (RPE) cells is one of the features of age-related macular degeneration (AMD) pathogenesis. We have previously shown that RPE cells from AMD donors have a distinct gene expression profile as well as distinct phenotype when compared to age-matched controls. Here, we analyze the gene expression pattern of these lines to investigate whether these differences observed at the RPE manifest at the fibroblast and induced pluripotent stem cell (iPSC) level.
iPSCs were generated from fibroblasts isolated from four AMD patients (2 atrophic and 2 exudative) and three patients with no history of AMD (normal). RPE derived from iPSCs were generated using established protocols and analyzed by morphology, cell type specific marker expression, transepithelial resistance (TER), and phagocytosis of rod photoreceptor outer segments. Mitochondrial function using the Seahorse platform were analyzed as well. DNA microarray with 23,000 well annotated genes were performed on fibroblast, iPSC and iPSC-derived RPE.
iPSCs and differentiated RPE displayed cell-type-specific morphology and markers. The TER and phagocytic capacity were maintained with no differences among iPSC-derived RPE cells. Mitochondrial respiration was reduced in AMD patient donor iPSC-derived RPE cells, but not in fibroblast cells from the same donors. Compared to controls, the transcriptome of RPE cells derived from AMD patients show a distinct gene expression pattern. A majority of these genes were not differently expressed in fibroblast or iPSCs when comparing donor lines from AMD patients and age-matched controls. Alterations include downregulation of genes responsible for cell attachment, metabolic-related pathways, and transcriptional regulating genes for RPE differentiation.
Here, we provide evidence that RPE cells differentiated from iPSCs rom AMD patients have a distinct gene expression profile when compared to cells derived from patients with no history of AMD. This observation is accompanied with a reduction in metabolic capacity in lines derived from AMD patients. These distinct gene expression patterns and associated biological phenotypes only appear at the RPE level. These patterns were not observed in fibroblast or iPSC cells from the same donors. Further exploration of the critical differences among normal RPE and diseased patients will pave the way for novel treatments for AMD.
This is a 2020 ARVO Annual Meeting abstract.
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