Dataset Information

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.

SUBMITTER: Bennis A

PROVIDER: S-EPMC5602068 | biostudies-literature | 2017 Oct

REPOSITORIES: biostudies-literature

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

Bennis A A Jacobs J G JG Catsburg L A E LAE Ten Brink J B JB Koster C C Schlingemann R O RO van Meurs J J Gorgels T G M F TGMF Moerland P D PD Heine V M VM Bergen A A AA

Stem cell reviews and reports 20171001 5

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 sta ...[more]

PMID: 28730556

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Project description:The therapeutic potential of pluripotent stem cells is great as they promise to usher in a new era of medicine where cells or organs may be prescribed to replace dysfunctional tissue. At the forefront are efforts in the eye to develop this technology as it lends itself to in vivo monitoring and sophisticated non-invasive imaging modalities. In the retina, retinal pigment epithelium (RPE) is the most promising replacement cell as it has a single layer, is relatively simple to transplant, and is associated with several eye diseases. However, after transplantation, the cells may transform and cause complications. This transformation may be partially due to incomplete maturation. With the goal of learning how to mature RPE, we compared induced pluripotent stem cell-derived RPE (iPSC-RPE) cells with adult human primary RPE (ahRPE) cells and the immortalized human ARPE-19 line. We cultured ARPE-19, iPSC-RPE, and ahRPE cells for one month, and evaluated morphology, RPE marker staining, and transepithelial electrical resistance (TEER) as quality control indicators. We then isolated RNA for bulk RNA-sequencing and DNA for genotyping. We genotyped ahRPE lines for the top age-related macular degeneration (AMD) and proliferative vitreoretinopathy (PVR) risk allele polymorphisms. Transcriptome data verified that both adult and iPSC-RPE exhibit similar RPE gene expression signatures, significantly higher than ARPE-19. In addition, in iPSC-RPE, genes relating to stem cell maintenance, retina development, and muscle contraction were significantly upregulated compared to ahRPE. We compared ahRPE to iPSC-RPE in a model of epithelial-mesenchymal transition (EMT) and observed an increased sensitivity of iPSC-RPE to producing contractile aggregates in vitro which resembles incident reports upon transplantation. P38 inhibition was capable of inhibiting iPSC-RPE-derived aggregates. In summary, we find that the transcriptomic signature of iPSC-RPE conveys an immature RPE state which may be ameliorated by targeting "immature" gene regulatory networks.

Project description:Retinal pigment epithelium (RPE) differentiated from human induced pluripotent stem cells, called induced retinal pigment epithelium (iRPE), is being explored as a cell-based therapy for the treatment of retinal degenerative diseases, especially age-related macular degeneration. The success of RPE implantation is linked to the use of biomimetic scaffolds that simulate Bruch's membrane and promote RPE maturation and integration as a functional tissue. Due to difficulties associated with animal protein-derived scaffolds, including sterility and pro-inflammatory responses, current practices favor the use of synthetic polymers, such as polycaprolactone (PCL), for generating nanofibrous scaffolds. In this study, we tested the hypothesis that plant protein-derived fibrous scaffolds can provide favorable conditions permissive for the maturation of RPE tissue sheets in vitro. Our natural, soy protein-derived nanofibrous scaffolds exhibited a J-shaped stress-strain curve that more closely resembled the mechanical properties of native tissues than PCL with significantly higher hydrophilicity of the natural scaffolds, favoring in vivo implantation. We then demonstrate that iRPE sheets growing on these soy protein scaffolds are equivalent to iRPE monolayers cultured on synthetic PCL nanofibrous scaffolds. Immunohistochemistry demonstrated RPE-like morphology and functionality with appropriate localization of RPE markers RPE65, PMEL17, Ezrin, and ZO1 and with anticipated histotypic polarization of vascular endothelial growth factor and pigment epithelium-derived growth factor as indicated by enzyme-linked immunosorbent assay. Scanning electron microscopy revealed dense microvilli on the cell surface and homogeneous tight junctional contacts between the cells. Finally, comparative transcriptome analysis in conjunction with principal component analysis demonstrated that iRPE on nanofibrous scaffolds, either natural or synthetic, matured more consistently than on nonfibrous substrates. Taken together, our studies suggest that the maturation of cultured iRPE sheets for subsequent clinical applications might benefit from the use of nanofibrous scaffolds generated from natural proteins. Impact statement Induced retinal pigment epithelium (iRPE) from patient-derived induced pluripotent stem cells (iPSCs) may yield powerful treatments of retinal diseases, including age-related macular degeneration. Recent studies, including early human clinical trials, demonstrate the importance of selecting appropriate biomaterial scaffolds to support tissue-engineered iRPE sheets during implantation. Electrospun scaffolds show particular promise due to their similarity to the structure of the native Bruch's membrane. In this study, we describe the use of electroprocessed nanofibrous soy protein scaffolds to generate polarized sheets of human iPSC-derived iRPE sheets. Our evaluation, including RNA-seq transcriptomics, indicates that these scaffolds are viable alternatives to scaffolds electrospun from synthetic polymers.

Project description:PURPOSE: The molecular mechanisms associated with human retinal pigment epithelium (RPE) development constitute the basis for cell replacement therapy for the treatment of retinal degenerative diseases. In the current study, gene expression analysis of the human fetal RPE during development was performed and was compared with the human native RPE. METHODS: Microdissection of the human RPE at three time points (13 weeks and 16 weeks of gestation and in mature adult eyes) was performed, and total RNA was isolated. Equal amounts of RNA were pooled from two or three independent donor eyes for each time point in each group. Gene expression was analyzed by hybridization to microarray chips. Validation was accomplished by comparing the microarray expression pro?les with quantitative real-time reverse transcriptase-polymerase chain reaction (qRT(2)-PCR) analysis of selected genes and by comparing selected expression pro?les with predicted pro?les based on previous studies. RESULTS: Of the 45,033 probe sets on the microarray, 30,736 were detected. A total of 3,498 differentially expressed genes could be clustered into eight patterns of expression that were statistically significant. Analysis of the expression patterns of genes coding for key functions (pigment synthesis, visual cycle, phagocytosis, adherens and tight junctions, and transcellular transport) indicated that the human RPE achieves a high degree of maturity during early pregnancy. Compared with 154 signature genes in the RPE, 148 candidate genes were identified in this study, including 53 downregulated genes and 5 upregulated genes. The qRT(2)-PCR results showed similar expression trends to those obtained by microarray analysis at the three time points. CONCLUSIONS: This study demonstrated gene expression profiles in the human RPE during normal development. These ?ndings indicate that the human RPE has different expression patterns than those of other animals. The results of this study may be helpful in furthering the understanding of the developmental processes occurring in humans and of the differentiation of RPE cells derived from human embryonic stem cells and from human induced pluripotent stem cells.

Project description:The therapeutic potential of pluripotent stem cells is great as they promise to Q7 usher in a new era of medicine where cells or organs may be prescribed to replace dysfunctional tissue. At the forefront are efforts in the eye to develop Q8 this technology as it lends itself to in vivo monitoring and sophisticated imaging modalities. In the retina, retinal pigment epithelium (RPE) is the most promising replacement cell as it has a single layer, is relatively simple to transplant, and is associated with dozens of eye diseases. However, after transplantation, they may transform and cause complications. This transformation may be partially due to incomplete maturation. With the goal of learning how to mature RPE, we compared iPSC-RPE with adult primary RPE and the immortalized ARPE-19 line. We cultured ARPE-19, iPSC-RPE, and adult human RPE for one month, evaluating morphology, RPE marker staining, and transepithelial electrical resistance as quality control indicators. We then isolated RNA for bulk RNAsequencing and DNA for genotyping. We genotyped adult RPE lines for the top age-related macular degeneration (AMD) and proliferative vitreoretinopathy (PVR) risk allele polymorphisms. Transcriptome data verified that both adult and iPSC-RPE exhibit similar RPE gene expression signatures, significantly more than ARPE-19. In addition, in iPSC-RPE, gene networks relating to epithelial to mesenchymal transition (EMT), stem cell maintenance, retina development, and muscle contraction were significantly elevated compared to those of adult RPE. We compared adult human RPE to iPSC-RPE in a model of EMT and observed an increased sensitivity of iPSC-RPE to producing contractile aggregates in vitro which resembles incident reports upon transplantation. P38 inhibition was capable of inhibiting iPSC-RPE–derived aggregates. In summary, we find that the transcriptomic signature of iPSC-RPE conveys an immature RPE state which may be ameliorated by targeting “immature” gene regulatory networks.

Dataset Information

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

Publications

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

Similar Datasets

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