Intracellular signaling pathways regulating pluripotency of embryonic stem cells.

Department of Stem Cell Biology, Institute for Frontier Medical Sciences, Kyoto University, Kyoto 606-8507, Japan.
Current Stem Cell Research & Therapy (Impact Factor: 2.86). 02/2006; 1(1):103-11. DOI: 10.2174/157488806775269061
Source: PubMed

ABSTRACT The cytokine LIF and its downstream effector STAT3 are essential for maintenance of pluripotency in mouse ES cells. The requirement for the transcription factor Oct3/4 for ES cell pluripotency is also well-documented. However, LIF is not involved in self-renewal of human ES cells, suggesting that other pathways must play an important role in this process. The importance of other signal transduction pathways, including BMP and Wnt signalings, as well as novel transcription factors such as Nanog, is now being recognized. We will review the rapid progress that has been made in identifying and dissecting the intracellular signaling pathways that contribute to self-renewal of pluripotent mouse and human ES cells.

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    ABSTRACT: In mouse embryonic cells, ligand-activated retinoic acid receptors (RARs) play a key role in inhibiting pluripotency-maintaining genes and activating some major actors of cell differentiation. To investigate the mechanism underlying this dual regulation, we performed joint RAR/RXR ChIP-seq and mRNA-seq time series during the first 48 h of the RA-induced Primitive Endoderm (PrE) differentiation process in F9 embryonal carcinoma (EC) cells. We show here that this dual regulation is associated with RAR/RXR genomic redistribution during the differentiation process. In-depth analysis of RAR/RXR binding sites occupancy dynamics and composition show that in undifferentiated cells, RAR/RXR interact with genomic regions characterized by binding of pluripotency-associated factors and high prevalence of the non-canonical DR0-containing RA response element. By contrast, in differentiated cells, RAR/RXR bound regions are enriched in functional Sox17 binding sites and are characterized with a higher frequency of the canonical DR5 motif. Our data offer an unprecedentedly detailed view on the action of RA in triggering pluripotent cell differentiation and demonstrate that RAR/RXR action is mediated via two different sets of regulatory regions tightly associated with cell differentiation status. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.
    Nucleic Acids Research 04/2015; DOI:10.1093/nar/gkv370 · 8.81 Impact Factor
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    ABSTRACT: Embryonic stem cells (ESCs) are maintained in an undifferentiated state via expression of the core transcriptional factors Nanog, Oct4 and Sox2. However, the epigenetic regulation of pluripotency is poorly understood. Differentiation of ESCs is accompanied by a global reduction of panacetylation of histones H3 and H4 suggesting that histone acetylation plays an important role in maintenance of ESC pluripotency. Acetylated lysine residues on histones are "read" by members of the bromodomain family that includes BET (bromodomain and extra-terminal domain) proteins for which highly potent and selective inhibitors have been developed. Here we demonstrate that the pan-BET bromodomain inhibitor JQ1 induces rapid spontaneous differentiation of murine ESCs by inducing marked transcriptional down-regulation of Nanog as well as the stemness markers Lefty1 and Lefty2 but not Myc, often used as a marker of BET inhibitor activity in cancer. We show that the effects of JQ1 are recapitulated by knockdown of the BET family member BRD4 implicating this protein in Nanog regulation. These data are also supported by chromatin immunoprecipitation experiments which confirm BRD4 binding at the Nanog promoter that is known to require acetylation by the histone acetyltransferase MOF for transcriptional activity. In further support of our findings, we show that JQ1 antagonises the stem cell promoting effects of the histone deacetylase inhibitors sodium butyrate and valproic acid. Our data suggest that BRD4 is critical for maintenance of ESC pluripotency and that this occurs primarily through maintenance of Nanog expression.
    Stem Cells and Development 11/2014; 24(7). DOI:10.1089/scd.2014.0302 · 4.20 Impact Factor
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    ABSTRACT: Human embryonic stem cells (hESCs) have received considerable attention due to their therapeutic potential and their usefulness in understanding early development and cell fate commitment. In order to appreciate the unique properties of these pluripotent, self-renewing cells, we have performed an in-depth multidimensional fractionation followed by LC-MS/MS analysis of the hESCs harvested from defined media to elucidate expressed, phosphorylated, O-GlcNAc modified, and secreted proteins. From the triplicate analysis, we were able to assign more than 3000 proteins with less than 1% false-discovery rate. This analysis also allowed us to identify nearly 500 phosphorylation sites and 68 sites of O-GlcNAc modification with the same high confidence. Investigation of the phosphorylation sites allowed us to deduce the set of kinases that are likely active in these cells. We also identified more than 100 secreted proteins of hESCs that likely play a role in extracellular matrix formation and remodeling, as well as autocrine signaling for self-renewal and maintenance of the undifferentiated state. Finally, by performing in-depth analysis in triplicate, spectral counts were obtained for these proteins and post-translationally modified peptides, which will allow us to perform relative quantitative analysis between these cells and any derived cell type in the future.This article is protected by copyright. All rights reserved
    Proteomics 01/2015; 15(2-3). DOI:10.1002/pmic.201400132 · 3.97 Impact Factor


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