Stem Cell Derived Retinal Pigment Epithelium: The Role of Pigmentation as Maturation Marker and Gene Expression Profile Comparison with Human Endogenous Retinal Pigment Epithelium.

Abstract

In age-related macular degeneration (AMD) the retinal pigment epithelium (RPE) deteriorates, leading to photoreceptor decay and severe vision loss. New therapeutic strategies aim at RPE replacement by transplantation of pluripotent stem cell (PSC)-derived RPE. Several protocols to generate RPE have been developed where appearance of pigmentation is commonly used as indicator of RPE differentiation and maturation. It is, however, unclear how different pigmentation stages reflect developmental stages and functionality of PSC-derived RPE cells. We generated human embryonic stem cell-derived RPE (hESC-RPE) cells and investigated their gene expression profiles at early pigmentation (EP) and late pigmentation (LP) stages. In addition, we compared the hESC-RPE samples with human endogenous RPE. We used a common reference design microarray (44 K). Our analysis showed that maturing hESC-RPE, upon acquiring pigmentation, expresses markers specific for human RPE. Interestingly, our analysis revealed that EP and LP hESC-RPE do not differ much in gene expression. Our data further showed that pigmented hESC-RPE has a significant lower expression than human endogenous RPE in the visual cycle and oxidative stress pathways. In contrast, we observed a significantly higher expression of pathways related to the process adhesion-to-polarity model that is typical of developing epithelial cells. We conclude that, in vitro, the first appearance of pigmentation hallmarks differentiated RPE. However, further increase in pigmentation does not result in much significant gene expression changes and does not add important RPE functionalities. Consequently, our results suggest that the time span for obtaining differentiated hESC-RPE cells, that are suitable for transplantation, may be greatly reduced.Electronic supplementary materialThe online version of this article (doi:10.1007/s12015-017-9754-0) contains supplementary material, which is available to authorized users.

RETRACTED: Drug Flux across RPE Cell Models: The Hunt for an Appropriate Outer Blood–Retinal Barrier Model for Use in Early Drug Discovery

“…In addition to clinical cell replacement therapy applications [19], the RPE cells differentiated from human embryonic (hESC) or human-induced pluripotent stem cells (hiPSC) are valuable in retinal research as they display a mature RPE phenotype after differentiation [20][21][22][23][24]. However, there is rather limited knowledge regarding the compound permeation of small molecular-weight compounds across hESC-RPE cells [25,26], and therefore, the applicability of hESC-RPE in early drug development is still unclear.…”

A Multi-Omics Approach Identifies Key Regulatory Pathways Induced by Long-Term Zinc Supplementation in Human Primary Retinal Pigment Epithelium

“…The effects of zinc in sub-RPE deposit formation in clinical studies are varied (see review [ 73 , 74 ]) and will require further investigations, probably with the use of methods that are able to specifically identify sub-RPE deposits in a clinical setting [ 75 , 76 , 77 ]. Changes in cell adhesion to polarity [ 78 ] and modulation of extracellular matrix organization had also been reported in AMD [ 31 , 79 ] which highlight another layer of complexity of zinc action on the RPE. As RPE activation and migration are significant clinical signs of the progression of AMD [ 80 ], this finding could point to new studies in which the clinical effects of zinc could be evaluated based on these new clinical endpoints.…”

Nicotinamide, iRPE-in-a dish, and age-related macular degeneration therapy development

“…Also, at least one sex-specific susceptibility locus for AMD has been identified (14). Although Blenkinsop and coworkers (15) found that stem cell derived RPE essentially reflects the key features of native RPE, we recently also found that there's still considerable non-sex influenced whole genome variation between stem cell derived RPE and native RPE (16). These more or less contrasting data, may results from the fact that there are now multiple, slightly different, protocols to derive RPE from stem cells (17)(18)(19)(20).…”