Project description:Transplantation of ex vivo expanded limbal stem cells (LSC) is the main treatment for limbal stem cell deficiency though the clinical problem of donor tissues shortage. Recently, as the development of tissue engineering, embryonic stem cells (ESC) derived corneal epithelial-like cells (ESC-CEC) has become a new direction to this issue.Our group successfully induced ESC into corneal epithelial-like cells, and in the present study we explored various aspects of physiological properties of ESC-CEC. The experiment included three samples: hES, the human embryonic stem cell line H1, RA_SB, the corneal epithelial-like cells derived from hES by differentiation with RA and SB, epithelial_cell, the primary human limbal stem cells from cadaver eyes. hES, the human embryonic stem cell line H1, RA_SB, the corneal epithelial-like cells derived from hES by differentiation with RA and SB, epithelial_cell, the primary human limbal stem cells from cadaver eyes.
Project description:Limbal epithelial stem cell (LESC) deficiency represents a significant clinical problem especially in bilateral cases. Induced pluripotent stem cells (iPSC) may be a promising source of LESC, allowing standardized and continual propagation and banking. The objective of this study was to generate iPSC from human limbal epithelial cultures and differentiate them back into limbal epithelial cells using substrata mimicking the natural LESC niche. Using Yamanaka’s episomal vectors limbal-derived iPSC were reprogrammed from LESC cultured from donor corneoscleral rims and from human skin fibroblasts. A clone from limbal-derived iPSC expressed stemness markers, had a diploid karyotype, and produced teratomas in nude mice representing three germ layers. Compared to parental LESC, this clone had fewer specific gene methylation changes revealed using the Illumina Infinium Methylation 450k Beadchips than compared to skin fibroblasts. The expression of putative LESC markers was examined by quantitative RT-PCR and immunostaining in limbal-derived and fibroblast-derived iPSC cultured on denuded human amniotic membrane or denuded cornea. Limbal-derived iPSC had markedly stronger expression of PAX6, ABCG2, Np63, keratins 14, 15, 17, and N-cadherin than fibroblast-derived iPSC. On denuded corneas, limbal-derived iPSC showed the expression of differentiated corneal keratins 3 and 12. The data suggest that iPSC differentiation to a desired lineage may be facilitated by their generation from the same tissue. This may be related to preservation of parental tissue epigenetic methylation signatures in iPSC and use of biological substrata similar to the natural niche of parental cells. The data pave the way for generating transplantable LESC from limbal-derived iPSC. Bisulphite converted DNA from the 12 samples were hybridised to the Illumina Infinium 450k Human Methylation Beadchip
Project description:Limbal epithelial stem cell (LESC) deficiency represents a significant clinical problem especially in bilateral cases. Induced pluripotent stem cells (iPSC) may be a promising source of LESC, allowing standardized and continual propagation and banking. The objective of this study was to generate iPSC from human limbal epithelial cultures and differentiate them back into limbal epithelial cells using substrata mimicking the natural LESC niche. Using Yamanaka’s episomal vectors limbal-derived iPSC were reprogrammed from LESC cultured from donor corneoscleral rims and from human skin fibroblasts. A clone from limbal-derived iPSC expressed stemness markers, had a diploid karyotype, and produced teratomas in nude mice representing three germ layers. Compared to parental LESC, this clone had fewer specific gene methylation changes revealed using the Illumina Infinium Methylation 450k Beadchips than compared to skin fibroblasts. The expression of putative LESC markers was examined by quantitative RT-PCR and immunostaining in limbal-derived and fibroblast-derived iPSC cultured on denuded human amniotic membrane or denuded cornea. Limbal-derived iPSC had markedly stronger expression of PAX6, ABCG2, Np63, keratins 14, 15, 17, and N-cadherin than fibroblast-derived iPSC. On denuded corneas, limbal-derived iPSC showed the expression of differentiated corneal keratins 3 and 12. The data suggest that iPSC differentiation to a desired lineage may be facilitated by their generation from the same tissue. This may be related to preservation of parental tissue epigenetic methylation signatures in iPSC and use of biological substrata similar to the natural niche of parental cells. The data pave the way for generating transplantable LESC from limbal-derived iPSC.
Project description:<p>The iPSCORE Resource of human induced pluripotent stem cells (hiPSCs) was created as part of the Next-Gen Consortium funded by the NHLBI. The overarching purpose of the iPSCORE Resource is to provide a large collection of hiPSCs for use in studying the impact of genetic variation on molecular and physiological phenotypes. This Resource is being used in a number of ongoing studies for which genomic data will be generated and deposited into public repositories and linked through dbGaP. A total of 273 individuals have participated in the study for which 222 have had hiPSCs generated from fibroblasts (available through WiCell (<a href="http://www.wicell.org/" target="_blank">http://www.wicell.org/</a>)). Of the 273 individuals, 181 are part of 55 families that include 24 monozygotic twin pairs and 5 dizygotic twin pairs, allowing for the incorporation of familial relationships into genetic analyses. Germline DNA has been sequenced from blood or fibroblast samples for all 273 individuals (see <a href="./study.cgi?study_id=phs001325">phs001325</a>) and other genomic data (RNA-seq, DNA methylation, and genotype arrays) has been generated from the 222 hiPSCs derived from a subset of these individuals (phs000924). Current studies include differentiation of these hiPSCs to other cell types, including cardiomyocytes and retinal pigment epithelium, and the generation of additional genomic data.</p>
Project description:<p>The iPSCORE Resource of human induced pluripotent stem cells (hiPSCs) was created as part of the Next-Gen Consortium funded by the NHLBI. The overarching purpose of the iPSCORE Resource is to provide a large collection of hiPSCs for use in studying the impact of genetic variation on molecular and physiological phenotypes. This Resource is being used in a number of ongoing studies for which genomic data will be generated and deposited into public repositories and linked through dbGaP. A total of 273 individuals have participated in the study for which 222 have had hiPSCs generated from fibroblasts (available through WiCell (<a href="http://www.wicell.org/" target="_blank">http://www.wicell.org/</a>)). Of the 273 individuals, 181 are part of 55 families that include 24 monozygotic twin pairs and 5 dizygotic twin pairs, allowing for the incorporation of familial relationships into genetic analyses. Germline DNA has been sequenced from blood or fibroblast samples for all 273 individuals (this study) and other genomic data (RNA-seq, DNA methylation, and genotype arrays) has been generated from the 222 hiPSCs derived from a subset of these individuals (<a href="./study.cgi?study_id=phs000924">phs000924</a>). Current studies include differentiation of these hiPSCs to other cell types, including cardiomyocytes and retinal pigment epithelium, and the generation of additional genomic data.</p>
Project description:Chavez2009 - a core regulatory network of OCT4 in human embryonic stem cells
A core OCT4-regulated network has been identified as a test case, to analyase stem cell characteristics and cellular differentiation.
This model is described in the article:
In silico identification of a core regulatory network of OCT4 in human embryonic stem cells using an integrated approach.
Chavez L, Bais AS, Vingron M, Lehrach H, Adjaye J, Herwig R
BMC Genomics, 2009, 10:314
Abstract:
BACKGROUND: The transcription factor OCT4 is highly expressed in pluripotent embryonic stem cells which are derived from the inner cell mass of mammalian blastocysts. Pluripotency and self renewal are controlled by a transcription regulatory network governed by the transcription factors OCT4, SOX2 and NANOG. Recent studies on reprogramming somatic cells to induced pluripotent stem cells highlight OCT4 as a key regulator of pluripotency.
RESULTS: We have carried out an integrated analysis of high-throughput data (ChIP-on-chip and RNAi experiments along with promoter sequence analysis of putative target genes) and identified a core OCT4 regulatory network in human embryonic stem cells consisting of 33 target genes. Enrichment analysis with these target genes revealed that this integrative analysis increases the functional information content by factors of 1.3 - 4.7 compared to the individual studies. In order to identify potential regulatory co-factors of OCT4, we performed a de novo motif analysis. In addition to known validated OCT4 motifs we obtained binding sites similar to motifs recognized by further regulators of pluripotency and development; e.g. the heterodimer of the transcription factors C-MYC and MAX, a prerequisite for C-MYC transcriptional activity that leads to cell growth and proliferation.
CONCLUSION: Our analysis shows how heterogeneous functional information can be integrated in order to reconstruct gene regulatory networks. As a test case we identified a core OCT4-regulated network that is important for the analysis of stem cell characteristics and cellular differentiation. Functional information is largely enriched using different experimental results. The de novo motif discovery identified well-known regulators closely connected to the OCT4 network as well as potential new regulators of pluripotency and differentiation. These results provide the basis for further targeted functional studies.
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Project description:There are a total of four samples each for this analysis. Each sample consists of the cells grown on three 10 cm culture plates. Each plate should have 2x106 cells for a total of 6x106 cells per sample when all three plates are combined. The first sample is undifferentiated human embryonic stem cells, the second sample is human glutamatergic neurons derived from those human embryonic stem cells, the third sample is undifferentiated human induced pluripotent stem cells and the fourth sample is human glutamatergic neurons derived from those human induced pluripotent stem cells.