Project description:Human induced pluripotent stem cells (iPS cells) resemble embryonic stem cells and can differentiate into cell derivatives of all three germ layers. However, frequently the differentiation efficiency of iPS cells into some lineages is rather poor. Here, we found that fusion of iPS cells with human hematopoietic stem cells (HSC) enhances iPS cell differentiation. Such iPS hybrids showed a prominent differentiation bias towards hematopoietic lineages but also towards other mesendodermal lineages. Additionally, during differentiation of iPS hybrids expression of early mesendodermal markers - Brachyury (T), MIX1 Homeobox-Like Protein 1 (MIXL1) and Goosecoid (GSC) - appeared with faster kinetics than in parental iPS cells. Following iPS hybrid differentiation there was a prominent induction of NODAL and inhibition of NODAL signaling blunted mesendodermal differentiation. This indicates that NODAL signaling is critically involved in mesendodermal bias of iPS hybrid differentiation. In summary, we demonstrate that iPS cell fusion with HSC prominently enhances iPS differentiation. 11 samples were hybridized GeneChip Human Gene 1.0 ST Arrays (Affymetrix)
Project description:Human induced pluripotent stem cells (iPS cells) resemble embryonic stem cells and can differentiate into cell derivatives of all three germ layers. However, frequently the differentiation efficiency of iPS cells into some lineages is rather poor. Here, we found that fusion of iPS cells with human hematopoietic stem cells (HSC) enhances iPS cell differentiation. Such iPS hybrids showed a prominent differentiation bias towards hematopoietic lineages but also towards other mesendodermal lineages. Additionally, during differentiation of iPS hybrids expression of early mesendodermal markers - Brachyury (T), MIX1 Homeobox-Like Protein 1 (MIXL1) and Goosecoid (GSC) - appeared with faster kinetics than in parental iPS cells. Following iPS hybrid differentiation there was a prominent induction of NODAL and inhibition of NODAL signaling blunted mesendodermal differentiation. This indicates that NODAL signaling is critically involved in mesendodermal bias of iPS hybrid differentiation. In summary, we demonstrate that iPS cell fusion with HSC prominently enhances iPS differentiation.
Project description:Metabolism is vital to cellular function and tissue homeostasis during human lung development. In utero, embryonic pluripotent stem cells undergo endodermal differentiation towards a lung progenitor cell fate that can be mimicked in vitro using induced human pluripotent stem cells (hiPSCs) to study genetic mutations. To identify differences between wild type and surfactant protein B (SFTPB)-deficient cell lines during endoderm specification towards lung, we used an untargeted metabolomics approach to evaluate the developmental changes in metabolites. We found that the metabolites most enriched during the differentiation from pluripotent stem cell to lung progenitor cell, regardless of cell line, were sphingomyelins and phosphatidylcholines, two important lipid classes in fetal lung development. The SFTPB mutation had no metabolic impact on early endodermal lung development. The identified metabolite signatures during lung progenitor cell differentiation may be utilized as biomarkers for normal embryonic lung development.
Project description:1 million human pluripotent cells cultured as suspension aggregates (hES3-NKX2.5 cell line) were treated with 0, 7.5 or 15µM CHIR99021 in 1 or 3 ml RPMI/B27 (w/o insulin) for 24h to induce the differentiation of human pluripotent stem cells (hPSCs). CHIR99021 is a potent GSK3 inhibitor that results in prominent WNT pathway activation and thereby induces mesendodermal differentiation.
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:Transcriptomes were profiled along with the differentiation from human induced pluripotent stem cell (iPSC) to beta-like cell (BLC) with PAX4 knocked out or not.
Project description:Transcriptomes were profiled along with the differentiation from human induced pluripotent stem cell (iPSC) to beta-like cell (BLC) with PAX4 knocked out or not.
Project description:Here we analyzed undifferentiated cells and perfomed the Teratoma assay for a normal human embryonic stem cell line (H9(+Dox)), a human embryonic stem cell line with a mesendodermal differentiation bias (H9Hyb), a normal human induced pluripotent stem cell line (LU07), a human induced pluripotent stem cell line with reactivated transgenes (LU07+Dox) and a human embryonal carcinoma cell line (EC). The ability to form teratomas in vivo containing multiple somatic cell types is regarded as functional evidence of pluripotency for human pluripotent stem cells (hPSCs). Since the Teratoma assay is animal-dependent, laborious and only qualitative, the PluriTest and the hPSC ScoreCard assay have been developed as in vitro alternatives. Here we compared normal hPSCs, induced hPSCs (hiPSCs) with reactivated reprogramming transgenes and human embryonal carcinoma (hEC) cells in these assays. While normal hPSCs gave rise to typical teratomas, the xenografts of the hEC cells and the hiPSCs with reactivated reprogramming transgenes were largely undifferentiated and malignant. The hPSC ScoreCard assay confirmed the line-specific differentiation propensities in vitro. However, when undifferentiated cells were analysed with PluriTest only hEC cells were identified as abnormal whereas all other cell lines were indistinguishable and resembled normal hPSCs. Our results indicate that pluripotency assays are best selected on the basis of intended downstream applications.