Small molecules facilitate rapid and synchronous iPSC generation
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE57774 | GEO | 2014/09/23
SECONDARY ACCESSION(S): PRJNA248071
REPOSITORIES: GEO
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Project 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-β 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. 18 samples were analyzed in total, samples represent bulk cultures of reprogrammable-MEFs (Rep-MEFs) that express OKSM and were supplemented with ascorbic acid and GSK3i during iPS cell induction. Control samples represent similar bulk cultures of reprogrammable-MEFs that express OKSM but were not supplemented with ascorbic acid and GSK3i during iPS cell induction. GMP-iPSCs were generated using 48 hours of OKSM+AGi induction. Fibroblast-iPSCs were generated using 96 hours of OKSM+AGi induction.
2014-09-23 | E-GEOD-57774 | biostudies-arrayexpress
Project 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. Microarray analysis was performed during reprogramming or of iPSC lines derived upon Sumo2 knockdown Total RNA was isolated from day 6 reprogramming fibroblasts with or without Sumo2 knockdown; as well as stable iPSC clones derived from Sumo2 knockdown fibroblasts.
2016-03-03 | E-GEOD-76699 | biostudies-arrayexpress
Project 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. Microarray analysis was performed during reprogramming or of iPSC lines derived upon Sumo2 knockdown
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Project description:Brief expression of pluripotency-associated factors such as OCT4, KLF4, SOX2 and c-MYC (OKSM), in combination with differentiation-inducing signals, was reported to trigger transdifferentiation of fibroblasts into alternative cell types. Here, we show that OKSM expression gives rise to both induced pluripotent stem cells (iPSCs) and iNSCs under conditions that were previously shown to induce only NSC transdifferentiation. Fibroblast-derived iNSC colonies silenced retroviral transgenes and reactivated silenced X chromosomes, both hallmarks of pluripotent stem cells. Moreover, lineage tracing via an Oct4-CreER labeling system demonstrated that virtually all iNSC colonies originate from cells transiently expressing Oct4, whereas ablation of Oct4-positive cells prevented iNSC formation. Lastly, use of 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 using OKSM and related reprogramming factors requires passage through a transient iPSC state. 5 samples were anlyzed in total, 2 induced pluripotent stem cells (iPSCs), 1 neural stem cells (NSCs) and 2 induced NSCs (iNSCs)
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Project 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.
2015-04-30 | GSE65951 | GEO
Project description:The generation of induced pluripotent stem cells (iPSCs) often results in aberrant silencing of the imprinted Dlk1-Dio3 gene cluster, which compromises their ability to generate entirely iPSC-derived mice (âall-iPSC miceâ). Here, we show that reprogramming in the presence of ascorbic acid attenuates hypermethylation of Dlk1-Dio3 by enabling a chromatin configuration at its imprint control region that interferes with abnormal binding of the DNA methyltransferase Dnmt3a. This approach allowed us to generate adult all-iPSC mice from mature B cells, which have thus far failed to support the development of exclusively iPSC-derived postnatal mice. Our data demonstrate that factor-mediated reprogramming can endow a defined, terminally differentiated cell type with a developmental potential equivalent to that of embryonic stem cells. More generally, these findings indicate that the choice of culture conditions used for transcription factor-mediated reprogramming can strongly influence the epigenetic and biological properties of resultant iPSCs. This series consists of quadruplicated mRNA expression microarray data (Affymetrix mouse 430_2 3'-IVT array) for iPS cells derived from MEF cells under cell culture conditions with or without ascorbic acid supplementation. iPS cells were generated from MEFs of the Col-OKSM reprogrammable mice. In the presence of doxycycline, the reprogramming transcription factors Oct4, Sox2, Klf4, and cMyc were induced in MEFs to derivate iPS cells. Total RNA was isolated from iPS cells derivated in the presence or absence of ascorbic acid in culture medium.
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Project 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. Comparison of Nanog KO iPSCs to WT pluripotent cells.
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Project 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.
2014-01-28 | GSE53832 | GEO
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