Activin/Smad2-induced H3K27me3 reduction is crucial to initiate mesendoderm differentiation of ES Cells
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE81617 | GEO | 2016/11/30
SECONDARY ACCESSION(S): PRJNA322087
REPOSITORIES: GEO
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Project description:Activin and Wnt signaling are necessary and sufficient for mesendoderm (ME) differentiation of human embryonic stem cells (hESCs). In this study, we report that during the Activin and Wnt induced ME differentiation, Activin/Smad2 induces decrease of the repressive histone modification H3K27me3 by promoting proteasome-dependent degradation of EZH2. As a result, recruitment of the forkhead protein FOXH1 on open chromatin regions integrates the signals of Activin/Smad2 and Wnt/β-catenin to activate the expression of the ME genes including HAS2 and ALDH3A2. Knockdown of HAS2 and ALDH3A2 greatly attenuates ME differentiation. These findings unveil a pathway from extracellular signals to epigenetic modification-mediated gene activation during ME commitment.
2018-09-29 | GSE113047 | GEO
Project description:Cardiovascular diseases are a major cause of life-threatening burden around the world. The heart has a very low regeneration capacity and donor organs for transplantation are scarce. Therefore regeneration of lost myocardium with stem cell-derived cardiomyocytes (CMs) provides an attractive strategy for heart repair. Human pluripotent stem cells (hPSCs) can be efficiently differentiated in vitro into CMs but the molecular mechanisms behind this process are still not fully understood. In particular identification of secreted autocrine and/or paracrine factors that function as important extrinsic signals remained elusive because the mass spectrometry (MS)-based identification of secreted proteins from cell culture supernatants is impeded by high levels of albumin present in common differentiation media. Thus we established an albumin-free cardiomyogenic differentiation medium and performed secretomics at seven different time points during in vitro differentiation. This analysis led to the identification of 4832 proteins with 1802 being significantly altered during differentiation and 431 of these were annotated as secreted according to gene ontology. Bioinformatics revealed enrichment of extrinsic Wnt pathway-related proteins 3 days upon induction of differentiation and of extracellular matrix proteins in the resulting CMs. Numerous extrinsic components of Wnt, Activin A, Nodal, TGFβ, BMP or FGF signaling pathways were quantitatively assessed during differentiation. Notably, the abundance of pathway agonists was generally lower compared to the respective antagonists but their curves of progression over timer were rather similar. We hypothesize that Activin A, Nodal and TGFβ signaling are turned down shortly upon initiation of cardiac differentiation whereas BMP signaling is switched on. Wnt and FGF signaling peaks between d0 and d3 of differentiation and interestingly, Activin A and TGFβ signaling seem to be reactivated at the cardiac progenitor stages and/or in early CMs.
2018-06-20 | PXD008554 | Pride
Project description:We report genome-wide changes in chromatin state and transcriptional output following Wnt-priming and subsequent Activin induced differentiation of human embryonic stem cell and the effects of BET bromodomain inhibition during Wnt-priming. The two signals, Wnt and Activin, although provided sequentially, result in stable mesendoderm differentiation (Yoney et al., 2018).
2021-06-06 | GSE176222 | GEO
Project description:The ground state of pluripotency is defined as a basal proliferative state free of epigenetic restriction, represented by mouse embryonic stem cells (ESCs) cultured with two kinase inhibitors (so-called “2i”). Through comparison with serum-grown ESCs, we identify epigenetic features characterizing 2i ESCs by proteome profiling of chromatin including post-translational histone modifications. The most prominent difference is H3K27me3 and its enzymatic writer complex PRC2 that are highly abundant on eu- and heterochromatin in 2i ESCs, with H3K27me3 redistributing outside canonical PRC2 targets in a CpG-dependent fashion. Using PRC2-deficient 2i ESCs, we identify epigenetic crosstalk with H3K27me3, including significant increases in H4 acetylation and DNA methylation. This suggests that the unique H3K27me3 configuration protects 2i ESCs from preparation to lineage priming. Interestingly, removal of DNA methylation in PRC2-deficient 2i ESCs lacking H3K27me3 using 5-azacytidine hardly affected ESC viability and transcriptome, showing that ESCs are independent of both major repressive epigenetic marks.
2018-11-21 | PXD007154 | Pride
Project description:Normal cell growth is characterized by a regulated epigenetic program that drives cellular activities such as gene transcription, DNA replication and DNA damage repair. Perturbation of this epigenetic program can lead to events such as mis-regulation of gene transcription and diseases such as cancer. To begin to understand the epigenetic program correlated to the development of melanoma, we performed a quantitative mass spectrometric analysis of histone posttranslational modifications mis-regulated in melanoma cell culture. Aggressive melanoma cells were found to have elevated histone H3 lysine 27 trimethylation (H3K27me3) as well as over-expressed methyltransferase EZH2 that adds the specific modification. The altered epigenetic program that led to elevated H3K27me3 in melanoma cell culture was found to directly silence transcription of the tumor suppressor gene RUNX3. The elevated level of H3K27me3 and silencing of RUNX3 transcription was also validated in advanced stage human melanoma tissues. The study presented underscores the utility of using high resolution mass spectrometry to identify mis-regulated epigenetic programs in diseases such as cancer, which could ultimately lead to the identification of biological markers for diagnostic and prognostic applications.
2016-07-22 | MSV000079979 | MassIVE
Project description:This study describes the changes in epigenetic chromatin modifications during murine hematopoietic stem cell differentiation in vivo using a modified miniChIP-chip technology. We have addressed issues including bivalent (H3K4me3/H3K27me3) modifications, lineage priming hypothesis, and stem cell chromatin properties in our study described in Weishaupt et al., 2009 (Blood)
2009-11-09 | GSE18734 | GEO
Project description:Epigenetic priming factors establish a permissive epigenetic landscape which is not required until a later developmental or physiological time point, temporally uncoupling the presence of these factors with their phenotypic effects. One classic example of epigenetic priming is in the context of bivalent chromatin, found in pluripotent stem cells and early embryos at key developmental gene promoters marked by both activating-associated H3K4me3 and repressive-associated H3K27me3 histone modifications. It is currently unknown how these bivalent domains are targeted, or precisely how they impact on lineage commitment. Here we show that the small heterodimerising non-enzymatic DNA binding proteins Developmental Pluripotency Associated 2 (Dppa2) and 4 (Dppa4) act as epigenetic priming factors to establish bivalency at a subset of developmental genes. Dppa2/4 localise to the +1 nucleosome position of bivalent genes and while they are not required for pluripotency in embryonic stem cells (ESCs), double knockout cells fail to exit pluripotency and to differentiate efficiently, with delays in upregulating bivalently marked lineage genes. Proteomics reveal that Dppa2/4 interact on chromatin with members of the COMPASS and Polycomb complexes important for H3K4me3 and H3K27me3 deposition, respectively. Epigenetic profiling reveals a striking loss of H3K4me3, H3K27me3, and their associated enzymatic machinery at a significant subset of bivalent promoters in Dppa2/4 mutants, in addition to loss of H2A.Z and chromatin accessibility. In wild-type ESCs, these “Dppa2/4-dependent” bivalent promoters are characterised by low H3K4me3 enrichment and breadth, near-absent expression levels and initiating but not elongating RNA polymerase. Notably, Dppa2/4-dependent promoters are less evolutionarily conserved suggesting that they lack additional safeguard measures to maintain bivalency at these genes in the absence of Dppa2/4. Concomitantly with the loss of bivalency, Dppa2/4-dependent bivalent promoters gain DNA methylation and consequently are no longer able to be effectively activated upon ESC differentiation, leading to defects in cell fate acquisition. Our findings reveal a targeting principle for bivalency to developmental gene promoters poising them for future lineage specific gene activation.
2020-05-26 | PXD014981 | Pride
Project description:Normal cell growth is characterized by a regulated epigenetic program that drives cellular activities such as gene transcription, DNA replication and DNA damage repair. Perturbation of this epigenetic program can lead to events such as mis-regulation of gene transcription and diseases such as cancer. To begin to understand the epigenetic program correlated to the development of melanoma, we performed a quantitative mass spectrometric analysis of histone posttranslational modifications mis-regulated in melanoma cell culture. Aggressive melanoma cells were found to have elevated histone H3 lysine 27 trimethylation (H3K27me3) as well as over-expressed methyltransferase EZH2 that adds the specific modification. The altered epigenetic program that led to elevated H3K27me3 in melanoma cell culture was found to directly silence transcription of the tumor suppressor gene RUNX3. The elevated level of H3K27me3 and silencing of RUNX3 transcription was also validated in advanced stage human melanoma tissues. The study presented underscores the utility of using high resolution mass spectrometry to identify mis-regulated epigenetic programs in diseases such as cancer, which could ultimately lead to the identification of biological markers for diagnostic and prognostic applications.
2015-12-02 | PXD002471 | Pride
Project description:Chromatin modifications are increasingly recognized as a key mechanism in cancer. The histone methyl-transferase Enhancer of Zeste, Drosophila, Homolog 2 (EZH2) is the enzymatic subunit of the polycomb PRC2 complex and methylates histone H3K27, thereby, mediating gene silencing. Down-regulation of EZH2 by RNA interference in ET suppressed oncogenic transformation, tumor development and metastasis in a respective mouse model. Further microarray analysis of EZH2 knock down, or functionally linked HDAC-inhibitor treatment revealed an undifferentiated reversible phenotype in ET maintained by EZH2. EZH2 suppression resulted in a generalized loss of H3K27me3 as well as an increase in H3 acetylation levels. In addition, ChIP-Chip assays for H3K27me3 identified genes that had specifically lost H3K27me3 upon EZH2 silencing. These findings suggested that stemness features are preserved via epigenetic mechanisms. Taken together, the genetic EWS-Fli1 translocation is intimately linked to global and gene specific epigenetic alterations in ET biology. EZH2 mediates neuroectodermal and endothelial embryonal tumor stem cell growth and metastasic spread induced by a translocation derived chimeric transcription factor. Keywords: PNET, Ewing Tumor Epigenetic regulation A673 transiently transfected with siRNA-EZH2 and siRNA-scrambled were harvested and Chromatin-IPs of H3K27me3 or H3 followed by microarray hybridisation were carried out. For detailed procedures see Burdach et al. Epigenetic Maintenance of Stemness and Malignancy in Peripheral Neuroectodermal Tumors by EZH2.
2010-05-18 | E-GEOD-15890 | biostudies-arrayexpress
Project description:The epigenetic mechanisms that enable specialized astrocytes to retain neurogenic competence throughout adult life are still poorly understood. Here we show that astrocytes that serve as neural stem cells (NSCs) in the adult mouse subventricular zone (SVZ) express the histone methyltransferase EZH2. This Polycomb repressive factor is required for neurogenesis independent of its role in SVZ NSC proliferation, as Ink4a/Arf-deficiency in Ezh2-deleted SVZ NSCs rescues cell proliferation, but neurogenesis remains defective. Olig2 is a direct target of EZH2, and repression of this bHLH transcription factor is critical for neuronal differentiation. Furthermore, Ezh2 prevents the inappropriate activation of genes that specify non-SVZ neuronal subtypes. In the human brain, SVZ cells including local astroglia also express EZH2, correlating with postnatal neurogenesis. Thus, EZH2 is an epigenetic regulator that distinguishes neurogenic SVZ astrocytes, orchestrating distinct and separable aspects of adult stem cell biology, which has important implications for regenerative medicine and oncogenesis. Examination of histone modifications (H3K27me3 and H3K4me3) in subventricular zone neural stem cells
2014-05-02 | E-GEOD-56394 | biostudies-arrayexpress