Maturation,not initiation, is major roadblock during reprogramming toward pluripotency from human fibrobalsts
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE47489 | GEO | 2013/07/01
SECONDARY ACCESSION(S): PRJNA205860
REPOSITORIES: GEO
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Project description:Reprogrammed cells are reverted to non reprogrammed cell fate in a maturation step of reprogramming. Cell fate changes during reprogramming from fibroblasts to iPSC , N=60 fibrobalst lines, N=13 Undifferentiated pluripotent stem cells, N=16 Nascent reprogrammed cells, N=31
2013-07-01 | E-GEOD-47489 | biostudies-arrayexpress
Project description:Pluripotency can be induced in somatic cells by forced expression of POU domain, class 5, transcription factor 1 (OCT3/4), sex determining region Y-box 2 (SOX2), Kruppel-like factor 4 (KLF4), myelocytomatosis oncogene (c-MYC) (OSKM). However, factor-mediated direct reprogramming is generally regarded as an inefficient and stochastic event. Contrary to this notion, we herein demonstrate that most human adult dermal fibroblasts initiated the reprogramming process on receiving the OSKM transgenes. Within 7 d, ~20% of these transduced cells became positive for the TRA-1-60 antigen, one of the most specific markers of human pluripotent stem cells. However, only a small portion (~1%) of these nascent reprogrammed cells resulted in colonies of induced pluripotent stem cells after replating. We found that many of the TRA-1-60-positive cells turned back to be negative again during the subsequent culture. Among the factors that have previously been reported to enhance direct reprogramming, LIN28, but not Nanog homeobox (NANOG), Cyclin D1, or p53 shRNA, significantly inhibited the reversion of reprogramming. These data demonstrate that maturation, and not initiation, is the limiting step during the direct reprogramming of human fibroblasts toward pluripotency and that each proreprogramming factor has a different mode of action.
| S-EPMC3725041 | biostudies-literature
Project description:Reprogramming of mouse fibroblasts toward a myocardial cell fate by forced expression of cardiac transcription factors or microRNAs has recently been demonstrated. The potential clinical applicability of these findings is based on the minimal regenerative potential of the adult human heart and the limited availability of human heart tissue. An initial, but mandatory step toward clinical application of this approach is to establish conditions for conversion of adult human fibroblasts to a cardiac phenotype. Toward this goal, we sought to determine the optimal combination of factors necessary and sufficient for direct myocardial reprogramming of human fibroblasts. Here we show that four human cardiac transcription factors, including Gata4, Hand2, Tbx5, and myocardin, and two microRNAs, miR-1 and miR-133, activated cardiac marker expression in neonatal and adult human fibroblasts. After maintenance in culture for 4-11 weeks, human fibroblasts reprogrammed with these proteins and microRNAs displayed sarcomere-like structures and calcium transients, and a small subset of such cells exhibited spontaneous contractility. These phenotypic changes were accompanied by expression of a broad range of cardiac genes and suppression of non-myocyte genes. These findings indicate that human fibroblasts can be reprogrammed to cardiac-like myocytes by forced expression of cardiac transcription factors with muscle-specific microRNAs and represent a step toward possible therapeutic application of this reprogramming approach. Human foreskin fibroblasts were transduced with 5 transcription factors and total RNA was obtained 4 weeks later. total RNA was also obtained from human foreskin fibroblasts as a negative control and adult human heart tissue as a positive control. The expression level of genes in each sample was compared.
2013-01-18 | E-GEOD-43588 | biostudies-arrayexpress
Project description:Reprogramming of mouse fibroblasts toward a myocardial cell fate by forced expression of cardiac transcription factors or microRNAs has recently been demonstrated. The potential clinical applicability of these findings is based on the minimal regenerative potential of the adult human heart and the limited availability of human heart tissue. An initial, but mandatory step toward clinical application of this approach is to establish conditions for conversion of adult human fibroblasts to a cardiac phenotype. Toward this goal, we sought to determine the optimal combination of factors necessary and sufficient for direct myocardial reprogramming of human fibroblasts. Here we show that four human cardiac transcription factors, including Gata4, Hand2, Tbx5, and myocardin, and two microRNAs, miR-1 and miR-133, activated cardiac marker expression in neonatal and adult human fibroblasts. After maintenance in culture for 4-11 weeks, human fibroblasts reprogrammed with these proteins and microRNAs displayed sarcomere-like structures and calcium transients, and a small subset of such cells exhibited spontaneous contractility. These phenotypic changes were accompanied by expression of a broad range of cardiac genes and suppression of non-myocyte genes. These findings indicate that human fibroblasts can be reprogrammed to cardiac-like myocytes by forced expression of cardiac transcription factors with muscle-specific microRNAs and represent a step toward possible therapeutic application of this reprogramming approach.
2013-01-18 | GSE43588 | GEO
Project description:We recently showed that some human induced pluripotent stem cell (iPSC) clones were defective in neural differentiation and were marked with the activation of long term repeats (LTRs) of human endogenous retroviruses (HERVs). We herein demonstrated that these LTRs were transiently overexpressed during the generation of iPSCs and contributed to reprogramming. When the generation of iPSCs was completed, LTRs were re-suppressed to levels similar to those in human ES cells. However, differentiation-defective iPSC clones maintained high LTR expression levels, which indicated that these clones failed to complete reprogramming. lincRNA-RoR, a long intergenic non-coding RNA (lincRNA) that was previously shown to support the induction and maintenance of pluripotency, was detected among the LTR-driven transcripts. Short hairpin RNAs against the conserved sequence in LTRs or lincRNA-RoR markedly reduced the efficiency of iPSC generation. Reprogramming factors including OCT3/4, SOX2, and KLF4 bound to most LTRs. The expression of KLF4 was low in normal iPSC clones, but remained high in differentiation-defective clones. The forced expression of KLF4 in human embryonic stem cells led to the activation of LTRs and defects in neural differentiation. These results demonstrated that the transient overexpression of KLF4/LTR/lincRNA-RoR played crucial roles in reprogramming toward pluripotency in humans, whereas a failure in its re-silence resulted in differentiation defects. Four human induced pluripotent stem cell lines were subcloned into 55 separate lines. Bisulfite converted genomic DNA lysates from fibroblast, induced pluripotent stem cell, intermediate reprogrammed cell and embryonic stem cell lines were hybridized to Illumina HumanMethylation450 BeadChip.
2014-08-04 | E-GEOD-54848 | biostudies-arrayexpress
Project description:The role of sirtuins (SIRTs) in cancer biology has been the focus of recent research. The similarities between underlying pathways involved in the induction of pluripotent stem cells and transformation of cancer cells revealed the role of SIRTs in cellular reprogramming. Seven SIRTs have been identified in mammals and downregulation of SIRT2 was found to facilitate the generation of primed pluripotent stem cells, such as human induced pluripotent stem cells. Herein, we evaluated the role of SIRT2 in naive pluripotent stem cell generation using murine cells. We found that absolute depletion of SIRT2 in mouse embryonic fibroblasts resulted in a notable reduction in reprogramming efficiency. SIRT2 depletion not only upregulated elements of the INK4/ARF locus, which in turn had an antiproliferative effect, but also significantly altered the expression of proteins related to the PI3K/Akt and Hippo pathways, which are important signaling pathways for stemness. Thus, this study demonstrated that SIRT2 is required for cellular reprogramming to naive states of pluripotency in contrast to primed pluripotency states.
| S-EPMC6117269 | biostudies-literature
Project description:Embryonic stem cells (ESCs), which are derived from the primitive ectoderm of pre-implantation blastocysts, are pluripotent cells and can thus contribute to the formation of all somatic cell lineages in chimeric animals. Similarly, epiblast stem cells (EpiSCs), which are derived from epiblast tissue of post-implantation embryos, are also pluripotent and can give rise to derivatives of all three germ layers in teratoma assays. Introduction of the four transcription factors Oct4/Sox2/Klf4/c-Myc into somatic cells has been shown to generate induced pluripotent stem cells (iPSCs). iPSCs exhibit ESC-like properties and are virtually identical to ESCs with respect to a number of charactertistics. However, generation of EpiSC-like cells by direct reprogramming of somatic cells using these transcription factors has not been shown to date. Here we show that Yamanaka’s four transcription factors can be used to directly generate EpiSC-like iPS cells (ePSCs) under EpiSC culture conditions. These ePSCs are identical to EpiSCs with respect to morphology, gene expression pattern, epigenetic status, and chimera formation. This is the first study to demonstrate that the culture environment in transcription factor-mediated reprogramming determines the cell fate of the reprogrammed cell. We could therefore envision that we eventually are able to shape the identity of a directly reprogrammed cell at will simply by modulating the culture conditions. RNA samples to be analyzed on microarrays were prepared using Qiagen RNeasy columns with on-column DNA digestion. 500 ng of total RNA per sample was used as input into a linear amplification protocol (Ambion), which involved synthesis of T7-linked double-stranded cDNA and 12 hrs of in-vitro transcription incorporating biotin-labelled nucleotides. Purified and labelled cRNA was then hybridized for 18 hrs onto MouseRef-8 v2 expression BeadChips (Illumina) according to the manufacturer's instructions. After washing, as recommended, chips were stained with streptavidin-Cy3 (GE Healthcare) and scanned using the iScan reader (Illumina) and accompanying software. Samples were hybridized as biological replicates. 24 samples were analyzed: MEF: Female mouse embryonic fibroblast, 2 biological rep ESC OG2: OG2 female embryonic stem cell, 2 biological rep EpiSC OG2: OG2 female EpiSC grown as single cells with conditioned medium, 2 biological rep EpiSC GOF18: GOF18 EpiSC grown as single cells with conditioned medium, 2 biological rep EpiSC T9b: T9 EpiSC on MEFs in activin-containing CDM, harvested w/o feeders, subconfluent, 2 biological rep ePSC L4: EpiSC-like iPS Cells L4, MEF reprogrammed to EpiSCs with 4F, line L4, grown with LIF and activin, 2 biological rep ePSC L7: EpiSC-like iPS cells L7, MEF reprogrammed to EpiSCs with 4F, line L7, grown with LIF and activin, 2 biological rep ePSC C1: EpiSC-like iPS Cells C1, MEF reprogrammed to EpiSCs with 4F, line C1, grown with LIF and activin, 2 biological rep ePSC C3: EpiSC-like iPS Cells C3, MEF reprogrammed to EpiSCs with 4F, line C3, grown with LIF and activin, 2 biological rep ePSC-R: EpiSC-like iPS Cells reverted, L4 ePSC cells reverted to an ESC-like state using Klf4 virus, 2 biological rep ePSC-RC1: EpiSC-like iPS Cells reverted, L4 ePSR Cre1, Cre-treated L4 ePSR cells, line 1, 2 biological rep ePSC-RC2: EpiSC-like iPS Cells reverted, L4 ePSR Cre2, Cre-treated L4 ePSR cells, line 2, 2 biological rep
2010-12-08 | E-GEOD-21516 | biostudies-arrayexpress
Project description:We determined whether the changed imprinted genes are maintained or reverted to the parthenogenetic state when the reprogrammed cells are re-differentiated into specialized cell types. To address this question, we re-differentiated miPSCs into neural stem cells (miPS-NSCs) and compared them with biparental female NSCs (fNSCs) and parthenogenetic NSCs (pNSCs) large-scale gene expression analysis of miPS-NSCs, fNSCs, and pNSCs, using the Illumina gene expression array Total RNA obtained from the three different NSC samples
2013-03-20 | E-GEOD-37541 | biostudies-arrayexpress
Project description:Mouse B cells, upon ectopic expression of the transcription factor C/EBPalpha for 18h, can be reprogrammed to induced pluripotent stem (iPS) cells with extremely high efficiency. To understand the molecular control of this phenomenon we performed a time course proteomic analysis by label-free protein quantification of proteins during B cell reprogramming to iPS cells.
2016-02-24 | PXD002769 | Pride
Project description:The overexpression of defined transcription factors in somatic cells results in their reprogramming into induced pluripotent stem (iPS) cells. The extremely low efficiency and slow kinetics of in vitro reprogramming suggest that further rare events are required to generate iPS cells. The nature and identity of these events, however, remain elusive. We noticed that the reprogramming potential of primary murine fibroblasts into iPS cells decreases after serial passaging and the concomitant onset of senescence. Consistent with the notion that loss of replicative potential provides a barrier for reprogramming, here we show that cells with low endogenous p19(Arf) (encoded by the Ink4a/Arf locus, also known as Cdkn2a locus) protein levels and immortal fibroblasts deficient in components of the Arf-Trp53 pathway yield iPS cell colonies with up to threefold faster kinetics and at a significantly higher efficiency than wild-type cells, endowing almost every somatic cell with the potential to form iPS cells. Notably, the acute genetic ablation of Trp53 (also known as p53) in cellular subpopulations that normally fail to reprogram rescues their ability to produce iPS cells. Our results show that the acquisition of immortality is a crucial and rate-limiting step towards the establishment of a pluripotent state in somatic cells and underscore the similarities between induced pluripotency and tumorigenesis.
| S-EPMC3987892 | biostudies-literature