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GSE21348
Homo sapiens
13 Downloadable Samples
Affymetrix Human Gene 1.0 ST Array (hugene10st)
Description
Human iPS cells derived from normal and Fragile-X fibroblasts in order to assess the capability of Fragile-X iPS cells to be used as a model for different aspects of Fragile-X syndrome. Microarry analysis used to compare global gene expression between human ES cells, the normal and the mutant iPS cells and the original fibroblasts, to demonstrate that the overall reprogramming process succeeded, and that the FX-iPS cells are fully reprogrammed cells.
Publication Title
Differential modeling of fragile X syndrome by human embryonic stem cells and induced pluripotent stem cells.
Sample Metadata Fields
Specimen part, Disease, Cell line
View Samples- Mus musculus
- 7 Downloadable Samples
- Affymetrix Mouse Gene 2.0 ST Array (mogene20st)
Description
Cellular reprogramming from somatic cells to induced pluripotent stem cells (iPSCs) can be achieved through forced expression of the transcription factors Oct4, Klf4, Sox2 and c-Myc (OKSM). These factors, in combination with environmental cues, induce a stable intrinsic pluripotency network that confers indefinite self-renewal capacity on iPSCs. In addition to Oct4 and Sox2, the homeodomain-containing transcription factor Nanog is an integral part of the pluripotency network. Although Nanog expression is not required for the maintenance of pluripotent stem cells, it has been reported to be essential for the establishment of both embryonic stem cells (ESCs) from blastocysts and iPSCs from somatic cells. Here we revisit the role of Nanog in direct reprogramming. Surprisingly, we find that Nanog is dispensable for iPSC formation under optimized culture conditions. We further document that Nanog-deficient iPSCs are transcriptionally highly similar to wild-type iPSCs and support the generation of teratomas and chimeric mice. Lastly, we provide evidence that the presence of ascorbic acid in the culture media is critical for overcoming the previously observed reprogramming block of Nanog knockout cells.
Publication Title
Nanog is dispensable for the generation of induced pluripotent stem cells.
Sample Metadata Fields
Specimen part
View Samples- Homo sapiens
- 4 Downloadable Samples
- Affymetrix Human Gene 1.0 ST Array (hugene10st)
Description
Three induced pluripotent stem (iPS) cell lines were generated from pancreatic BCD (beta-cell-derived cells). One iPS cell clone was derived from pancreatic non-beta cells. We used microarrays to study the gene expression profiles of beta-iPSCs, and compared the expression of genes in their somatic parental cells and other ES and iPS cells.
Publication Title
Epigenetic memory and preferential lineage-specific differentiation in induced pluripotent stem cells derived from human pancreatic islet beta cells.
Sample Metadata Fields
Sex, Specimen part
View Samples- Mus musculus
- 11 Downloadable Samples
- Affymetrix Mouse Gene 2.0 ST Array (mogene20st)
Description
The reprogramming of somatic cells into induced pluripotent stem cells (iPSCs) upon overexpression of OCT4, KLF4, SOX2 and c-MYC (OKSM) provides a powerful system to interrogate basic mechanisms of cell fate change. However, iPSC formation with standard methods is typically protracted and inefficient, resulting in heterogeneous cell populations. We show that exposure of OKSM-expressing cells to both ascorbic acid and a GSK3- inhibitor (AGi) facilitates more synchronous and rapid iPSC formation from several mouse cell types. AGi treatment restored the ability of refractory cell populations to yield iPSC colonies, and it attenuated the activation of developmental regulators commonly observed during the reprogramming process. Moreover, AGi supplementation gave rise to chimera-competent iPSCs after as little as 48 h of OKSM expression. Our results offer a simple modification to the reprogramming protocol, facilitating iPSC induction at unparalleled efficiencies and enabling dissection of the underlying mechanisms in more homogeneous cell populations.
Publication Title
Small molecules facilitate rapid and synchronous iPSC generation.
Sample Metadata Fields
Specimen part, Treatment, Time
View Samples- Mus musculus
- 5 Downloadable Samples
- Affymetrix Mouse Gene 2.0 ST Array (mogene20st)
Description
Brief expression of pluripotency-associated factors such as Oct4, Klf4, Sox2 and c-Myc (OKSM), in combination with differentiation-inducing signals, has been reported to trigger transdifferentiation of fibroblasts into other cell types. Here we show that OKSM expression in mouse fibroblasts gives rise to both induced pluripotent stem cells (iPSCs) and induced neural stem cells (iNSCs) under conditions previously shown to induce only iNSCs. Fibroblast-derived iNSC colonies silenced retroviral transgenes and reactivated silenced X chromosomes, both hallmarks of pluripotent stem cells. Moreover, lineage tracing with an Oct4-CreER labeling system demonstrated that virtually all iNSC colonies originated from cells transiently expressing Oct4, whereas ablation of Oct4+ cells prevented iNSC formation. Lastly, an alternative transdifferentiation cocktail that lacks Oct4 and was reportedly unable to support induced pluripotency yielded iPSCs and iNSCs carrying the Oct4-CreER-derived lineage label. Together, these data suggest that iNSC generation from fibroblasts using OKSM and other pluripotency-related reprogramming factors requires passage through a transient iPSC state.
Publication Title
Lineage conversion induced by pluripotency factors involves transient passage through an iPSC stage.
Sample Metadata Fields
Sex, Specimen part
View Samples- Mus musculus
- 4 Downloadable Samples
- Affymetrix Mouse Gene 2.0 ST Array (mogene20st)
Description
The generation of induced pluripotent stem cells (iPSCs) from differentiated cells following forced expression of Oct4, Klf4, Sox2 and c-Myc (OKSM) is slow and inefficient, suggesting that transcription factors have to overcome somatic barriers that resist cell fate change. Here, we performed an ubiased serial shRNA enrichment screen to identify novel repressors of somatic cell reprogramming into iPSCs. This effort uncovered the sumoylation effector protein Sumo2 as one of the strongest roadblocks to iPSC formation. Depletion of Sumo2 both enhances and accelerates reprogramming, yielding transgene-independent, chimera-competent iPSCs after as little as 36 hours of OKSM expression. We further show that the Sumo2 pathway acts independently of exogenous c-Myc expression and in parallel with small molecule enhancers of reprogramming. Critically, suppression of SUMO2 also promotes the generation of human iPSCs. Together, our results reveal sumoylation as a crucial post-transcriptional mechanism that resists the acquisition of pluripotency from fibroblasts using defined factors.
Publication Title
A Serial shRNA Screen for Roadblocks to Reprogramming Identifies the Protein Modifier SUMO2.
Sample Metadata Fields
Sex, Specimen part, Time
View Samples- Homo sapiens
- 2 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
PAR-1 is known to be involved in the transition from non-metastatic to metastatic melanoma. We sought to determine the downstream target genes regulated by PAR-1 to determine how PAR-1 is contributing to the metastatic melanoma phenotype.
Publication Title
Protease activated receptor-1 inhibits the Maspin tumor-suppressor gene to determine the melanoma metastatic phenotype.
Sample Metadata Fields
Specimen part, Cell line
View Samples- Mus musculus
- 6 Downloadable Samples
Illumina HiSeq 2500
Description
Pancreatic ductal adenocarcinoma (PDAC) is a deadly disease and a major health problem in the United States. While the cytokine TGF-ß has been implicated in PDAC development, it can exert bot pro- and anti-tumorigenic effects that are highly context dependent and incompletely understood. To better characterize the responses of neoplastic pancreas cells to TGF-ß, three-dimensional (3D) cultures of KrasG12D-expressing mouse pancreatic epithelial cells were employed. While active exposure to exogenous TGF-ß caused the KrasG12D cells to growth arrest, its subsequent removal allowed the cells to enter a hyper-proliferative, quasi-mesenchymal (QM) and progenitor-like state. This transition was highly stable and maintained by autocrine TGF-ß signaling. Transient pulses of TGF-ß have been observed during pancreatitis, a major risk factor for PDAC, and may therefore serve to convert pre-existing KrasG12D-expressing cells into QM cells. While untreated KrasG12D cells formed simple cysts in vivo, QM cells formed ductal structures resembling human PanINs. Furthermore, markers of the QM state are expressed in human PDAC and are associated with worse outcomes. These data suggest that the QM state plays a role in PDAC development and may selectively contribute to more aggressive PDAC subtypes. This work therefore provides novel molecular insights into both PDAC development and the complex role of TGF-ß in tumorigenesis. Overall design: Three technical replicates per experimental group from one isolate were analyzed by RNA sequencing
Publication Title
Pre-neoplastic pancreas cells enter a partially mesenchymal state following transient TGF-β exposure.
Sample Metadata Fields
Subject
View Samples- Mus musculus
- 28 Downloadable Samples
- Affymetrix Mouse Genome 430A 2.0 Array (mouse430a2)
Description
This SuperSeries is composed of the SubSeries listed below.
Publication Title
A molecular roadmap of reprogramming somatic cells into iPS cells.
Sample Metadata Fields
Specimen part, Time
View Samples- Mus musculus
- 28 Downloadable Samples
Affymetrix Mouse Genome 430A 2.0 Array (mouse430a2)
Description
Factor induced reprogramming is a slow and inefficient process with only rare cells progressing towards induced pluripotent stem cells (iPSCs). Owing to these restraints, mechanistic studies have been limited to analyses of heterogeneous bulk populations undergoing reprogramming and partially reprogrammed cell lines. Here, by combining surface markers (Thy1, SSEA1) and an Oct4-GFP fluorescent reporter allele, we analyzed defined intermediate cell populations poised to becoming iPSCs at the transcriptional and epigenetic levels using genome-wide and single cell technologies. We found that factor-induced reprogramming elicits two discernible transcriptional waves that are characterized by the initial extinction of the somatic gene expression program and the concomitant acquisition of an ESC-like proliferative and metabolic state, followed by the activation of an embryonic pluripotent state primed for differentiation. The first wave is mostly driven by gene activation through c-Myc and gene repression by Klf4, whereas the second wave is a result of gradually activated Oct4/Sox2 targets in cooperation with Klf4 targets and other downstream regulators. While microRNA expression and enrichment for individual histone modifications (H3K4me3 or H3K27me3 enriched promoters) mirrored the observed biphasic transcriptional pattern, the establishment of bivalent domains (H3K4me3/H3K27me3 enriched promoters) occurred more gradually. In contrast, changes in DNA methylation took place predominantly at the end of reprogramming when cells assumed a stable pluripotent state. Cells that became refractory to reprogramming activated the first but failed to initiate the second transcriptional wave. However, introduction of additional copies of the reprogramming transgenes into these cells rescued their ability to form iPSCs, indicating that suboptimal transcription factor levels are a limiting factor for efficient iPSC formation. This integrative analysis allowed us to identify novel genes and microRNAs that enhance reprogramming and surface markers that further subdivide intermediate cell populations. Collectively, our data offer new mechanistic insights into the nature and sequence of molecular events inherent to cellular reprogramming and provide a valuable resource of molecules that may act as roadblocks during iPSC formation.
Publication Title
A molecular roadmap of reprogramming somatic cells into iPS cells.
Sample Metadata Fields
No sample metadata fields
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