SHEF1.3-derived retinal pigment epithelium for cell therapy is free of stem cell contaminants
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ABSTRACT: Safety is the principle consideration with any clinical program, for which hESC and their derived products hold specific challenges. Differentiated cell products derived from hESC must be free from pluripotent cells as these could potentially form teratomas. One relevant clinical program is transplantation of retinal pigment epithelial cells (RPE) derived from hESC. This has potential for halting visual decline in conditions where the RPE layer is damaged such as age-related macular degeneration (AMD). In this study we show that whole genome gene expression analysis of SHEF1.3 starting material and the P0 pigmented RPE foci shows that the two cell types are distinct.
Project description:Development of efficient and reproducible conditions for directed differentiation of pluripotent stem cells into specific cell types is important not only to understand early human development but also to enable more practical applications, such as in vitro models of disease, drug discovery, and cell therapies. The differentiation of stem cells to retinal pigment epithelium (RPE) in particular holds promise as a source of cells for therapeutic replacement in age-related macular degeneration. Here we show development of a robust and efficient method to derive RPE with high reproducibility in an adherent, monolayer system using sequential inhibition and activation of the Activin and BMP signalling pathways. We use whole genome transcript analysis to characterize cells at different stages of differentiation to gain further understanding of the developmental dynamics and fate specification of RPE.
Project description:Retinal pigment epithelium (RPE) cell integrity is critical to the maintenance of retinal function. Many retinopathies such as age-related macular degeneration (AMD) are caused by the degeneration or malfunction of the RPE cell layer. Replacement of diseased RPE with healthy, stem cell derived RPE is a potential therapeutic strategy for treating AMD. Human embryonic stem cells (hESC) differentiated into RPE progeny have potential to provide an unlimited supply of cells for transplantation but challenges around scalability and efficiency of the differentiation process still remain. Using hESC-derived RPE as a cellular model, we sought to understand mechanisms that could be modulated to increase RPE yield following differentiation. Our data show that activation of the cAMP pathway increases proliferation of dissociated RPE in culture, in part through inhibition of TGFβ signalling. This in turn results in enhanced uptake of epithelial identity. In line with these findings, targeted manipulation of the TGFβ pathway with small molecules produces an increase in efficiency of RPE re-epithelialization. Taken together, these data highlight mechanisms that promote epithelial fate acquisition in stem cell derived RPE. Modulation of these pathways has potential to favorably impact upon scalability and clinical translation of hESC-derived RPE as a cell therapy. A sample of Gene Pool™ cDNA, from human fetal normal brain tissue (Invitrogen D8830-01) is included for reference.
Project description:Retinal Pigment Epithelial (RPE) cells are located behind the retina and are critical for photoreceptor survival. Loss of RPE is associated with several pathogenic conditions such as Age Related Macular Degeneration and Retinitis Pigmentosa. RPE derived from human embryonic stem cells (hESC) offer a potential source for producing these cells for therapy. Here we report the molecular and cellular characterization of RPE differentiated from hESC. hESC derived RPE are capable of proliferation and lose their epithelial characteristics before becoming confluent and re-differentiating back into their typical pigmented, cobblestoned appearance. During the proliferative phase, they adopt a mesenchymal morphology and express mesenchymal markers. Our results demonstrate that this apparent Epithelial-Mesenchymal Transition is not regulated by the classical EMT transcription factors SNAIL and SLUG. Furthermore, it is possible to regulate RPE de-differentiation and re-differentiation by modulating the Wnt and BMP pathway respectively. These findings further our understanding of the genesis and expansion of RPE which is essential for their therapeutic use.
Project description:Retinal Pigment Epithelial (RPE) cells are located behind the retina and are critical for photoreceptor survival. Loss of RPE is associated with several pathogenic conditions such as Age Related Macular Degeneration and Retinitis Pigmentosa. RPE derived from human embryonic stem cells (hESC) offer a potential source for producing these cells for therapy. Here we report the molecular and cellular characterization of RPE differentiated from hESC. hESC derived RPE are capable of proliferation and lose their epithelial characteristics before becoming confluent and re-differentiating back into their typical pigmented, cobblestoned appearance. During the proliferative phase, they adopt a mesenchymal morphology and express mesenchymal markers. Our results demonstrate that this apparent Epithelial-Mesenchymal Transition is not regulated by the classical EMT transcription factors SNAIL and SLUG. Furthermore, it is possible to regulate RPE de-differentiation and re-differentiation by modulating the Wnt and BMP pathway respectively. These findings further our understanding of the genesis and expansion of RPE which is essential for their therapeutic use.
Project description:Human embryonic stem cell derived retinal pigmented epithelial cells (hESC-RPE) are in clinical trials for the treatment of macular diseases. Currently, these cells take over three months to derive and subsequent months to mature and characterize. After only five to six passages the cells begin to undergo an epithelial-to-mesenchymal transition and are unsuitable for cellular therapies. We describe a novel passaging protocol and show that inhibition of Rho-associated, coiled coil containing protein kinases (ROCK1 and ROCK2) using Y-27632, allows extended passage of hESC-RPE in serum-free culture with maintenance of the RPE phenotype. After 30 population doublings, hESC-RPE at passage 13 maintain normal karyotype, display typical, polarized epithelial morphology, and continue to express RPE-specific genes. Passage 13 hESC-RPE show protein localization patterns similar to passage 2 cells, and display similar levels of growth factor secretion and phagocytosis of photoreceptor outer segments. Microarray analysis from day 2 cells shows several key pathways are altered by ROCK inhibition, including stimulation of the cell cycle and suppression of TGFM-NM-2 and Wnt signaling. These findings describe a means to greatly increase the yield of functional hESC-RPE for use in research and clinical trials. Two-condition experiment, Control vs Y-27632 treated hESC-RPE passage 5. Biological replicates: 4 control, 4 Y-27632. The experiments were technically carried out as dual channel (eg, Cy3 and Cy5-labeled samples hybridized to the same array) but processed as though they are single channel (Cy3 and Cy5 signals are calculated; Cy3/Cy5 ratios are not calculated). Therefore, there are 4 raw data files for total 8 samples.
Project description:Here we demonstrate that hES cells can be reproducibly and efficiently induced to PAX6+ and OCT4- cells with the use of small molecules in animal-component free condition. We are also showing by whole genome microarray and single cell QPCR that induced cells express genes characteristic for the development of anterior neuroectoderm, in particular development of future forebrain. Note: The samples included in this experiment were processed in 3 separate batches and we performed a batch correction step in the analysis as indicated in the transformation protocol.
Project description:The integrity of the epithelium is maintained by a complex but regulated interplay of processes that allow seamless orchestration of a proliferative state into a stably differentiated state. In this study, using stem cell derived Retinal Pigment Epithelium (RPE) cells as a model; we have investigated the molecular mechanisms that affect attainment of the epithelial phenotype. We identify a novel role for the proto-oncogene FOXM1 in determining epithelial fate of RPE by directly regulating cell proliferation and by indirectly regulating expression of signalling factors BMP7 and Wnt5B; both of which are intimately required for eventual acquisition of the epithelial phenotype. This study uncovers the role of FOXM1 in a non-oncogenic, native-like setting and shows that human ES derived RPE can serve as a useful model system to address biological questions not restricted to visual function.
Project description:Stable clones of RPE-1 cells expressing tetracycline-inducible wild type SAS-6 or SAS-6ND were obtained via lentiviral gene transduction with the pLVX tet-on Advanced inducible gene expression system (Clontech). Stable expressors were derived by selection with 5 μg/mL puromycin (Sigma-Aldrich, UK). Doxycycline 1 microgram/mL was added to growth media for 6 days to induce SAS-6 expression. RNA was isolated from RPE-1 cells using the RNeasy mini kit (Qiagen, CA) according to the manufacturer’s protocol. Gene expression was profiled using GeneChip™ Human Transcriptome Array 2.0.
Project description:To assess the geome-wide similarities between primary fetal retinal pigmented epithelium (RPE) and stem-cell derived RPE, we performed whole genome microarray expression on primary RPE and both embryonic stem cell (ESC) derived RPE and induced pluripotent stem cell (iPSC) derived RPE. We found ES-derived RPE better resembles fetal RPE than iPS-derived RPE. Gene expression was measured in primary fetal RPE, ES-derived RPE, iPS-derived RPE. ES cells and BJ fibroblasts were used as controls.
Project description:Retinal pigment epithelium (RPE) cells can be obtained through in vitro differentiation of both embryonic stem cell (ESC) and induced pluripotent stem cells (iPSC) for cell replacement therapy. We have previously identified 87 signature genes relevant to RPE cell differentiation and function through transcriptome analysis of both human ESC- and iPSC-derived RPE as well as normal fetal RPE. Here, we profiled miRNA expression through small RNA-seq in human ESCs and their RPE derivatives. Much like conclusions drawn from our previous transcriptome analysis, we found that the overall miRNA landscape in RPE is distinct from ESCs and other differentiated somatic tissues. We also profiled miRNA expression during intermediate stages of RPE differentiation and identified unique subsets of miRNAs that are gradually up- or downregulated, suggesting dynamic regulation of these miRNAs is associated with the RPE differentiation process. Indeed, the down-regulation of a subset of miRNAs during RPE differentiation is associated with up-regulation of RPE-specific genes, such as RPE65, which is exclusively expressed in RPE. We conclude that miRNA signatures can be used to classify different degrees of in vitro differentiation of RPE from human pluripotent stem cells. We suggest that RPE-specific miRNAs likely contribute to the functional maturation of RPE in vitro, similar to the regulation of RPE-specific mRNA expression. Study miRNA in ESC-derived RPE