Filamin A Controls Embryonic Stem Cell Differentiation.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4599-4599
Author(s):  
Taisuke Kanaji ◽  
Takashi Okamura ◽  
Peter J. Newman
Keyword(s):  
Cell Differentiation ◽  
Signaling Pathways ◽  
Es Cells ◽  
Embryonic Stem ◽  
Stem Cell Differentiation ◽  
Embryoid Bodies ◽  
Actin Binding ◽  
Embryonic Stem Cell Differentiation ◽  
Filamin A ◽  
Es Cell

Abstract Abstract 4599 Filamin A is a major non-muscle actin binding protein that plays an important role in cross-linking cortical actin filaments into three-dimensional networks. In addition to its role as a cytoskeletal scaffolding molecule, Filamin A is also known to bind more than 30 other proteins, regulating their subcellular location and coordinating their ability to signal. To analyze the role of filamin A in mouse embryonic stem (ES) cell maturation, we generated filamin ALow ES cells by introducing a micro-RNA that specifically downregulates filamin A expression under the control of a cytomegalovirus promoter. Filamin ALow ES cells exhibited a more rounded morphology than did their wild-type filamin ANormal counterparts, and expressed increased levels of the ES cell transcription factor Nanog. In contrast, non-transfected cells in the same culture dish retained normal expression of filamin A, expressed low levels of Nanog, and exhibited a more elongated and spread phenotype characteristic of differentiating cells. Further evidence for a role for filamin A in ES cell differentiation was provided by the observation that withdrawing leukemia inhibitory factor (LIF) to induce ES cell differentiation was accompanied by increased expression of filamin A, a concomitant loss of Nanog expression, and acquisition of a differentiated morphology. Filamin ALow ES cells were able to retain their undifferentiated phenotype, as evaluated by alkaline phosphatase (Alp) activity, in the presence of a 10-fold lower concentration of LIF than was permissive for filamin ANormal ES cells, or following exposure to the differentiating agent, bone morphogenic protein 4 (BMP4). LIF-induced phosphorylation of ERK was decreased in filamin ALow relative to filamin ANormal ES cells, as was BMP-induced phosphorylation of Smad1/5 - two signaling pathways that initiate ES cell differentiation. Finally, embryoid bodies comprised of filamin ALow ES cells were unable to differentiate into CD41+ hematopoietic progenitor cells. Taken together, these data demonstrate that filamin A plays a previously unrecognized, but critical, scaffolding function that support both the LIF - ERK and BMP4 - Smad1/5 signaling pathways leading to ES and hematopoietic cell differentiation. Manipulation of filamin levels might be useful in the future to modulate the differentiation requirements for a variety of clinically-and therapeutically-useful stem cells. Disclosures: Newman: Novo Nordisk: Consultancy; New York Blood Center: Membership on an entity's Board of Directors or advisory committees.

scholarly journals Asf1a resolves bivalent chromatin domains for the induction of lineage-specific genes during mouse embryonic stem cell differentiation

2018 ◽  
Vol 115 (27) ◽  
pp. E6162-E6171 ◽  
Author(s):  
Yuan Gao ◽  
Haiyun Gan ◽  
Zhenkun Lou ◽  
Zhiguo Zhang
Keyword(s):  
Cell Differentiation ◽  
Es Cells ◽  
Embryonic Stem ◽  
Stem Cell Differentiation ◽  
Embryonic Stem Cell Differentiation ◽  
Es Cell ◽  
Nucleosome Assembly ◽  
Chromatin Domains ◽  
Nucleosome Disassembly ◽  
Lineage Specific Genes

Bivalent chromatin domains containing repressive H3K27me3 and active H3K4me3 modifications are barriers for the expression of lineage-specific genes in ES cells and must be resolved for the transcription induction of these genes during differentiation, a process that remains largely unknown. Here, we show that Asf1a, a histone chaperone involved in nucleosome assembly and disassembly, regulates the resolution of bivalent domains and activation of lineage-specific genes during mouse ES cell differentiation. Deletion of Asf1a does not affect the silencing of pluripotent genes, but compromises the expression of lineage-specific genes during ES cell differentiation. Mechanistically, the Asf1a–histone interaction, but not the role of Asf1a in nucleosome assembly, is required for gene transcription. Asf1a is recruited to several bivalent promoters, partially through association with transcription factors, and mediates nucleosome disassembly during differentiation. We suggest that Asf1a-mediated nucleosome disassembly provides a means for resolution of bivalent domain barriers for induction of lineage-specific genes during differentiation.

scholarly journals The Polycomb Group Protein Suz12 Is Required for Embryonic Stem Cell Differentiation

2007 ◽  
Vol 27 (10) ◽  
pp. 3769-3779 ◽  
Author(s):  
Diego Pasini ◽  
Adrian P. Bracken ◽  
Jacob B. Hansen ◽  
Manuela Capillo ◽  
Kristian Helin
Keyword(s):  
Cell Differentiation ◽  
Transcriptional Activation ◽  
Es Cells ◽  
Embryonic Stem ◽  
Stem Cell Differentiation ◽  
Polycomb Group ◽  
Embryonic Stem Cell Differentiation ◽  
Es Cell ◽  
Polycomb Group Protein ◽  
Specific Expression

ABSTRACT Polycomb group (PcG) proteins form multiprotein complexes, called Polycomb repressive complexes (PRCs). PRC2 contains the PcG proteins EZH2, SUZ12, and EED and represses transcription through methylation of lysine (K) 27 of histone H3 (H3). Suz12 is essential for PRC2 activity and its inactivation results in early lethality of mouse embryos. Here, we demonstrate that Suz12 −/− mouse embryonic stem (ES) cells can be established and expanded in tissue culture. The Suz12 −/− ES cells are characterized by global loss of H3K27 trimethylation (H3K27me3) and higher expression levels of differentiation-specific genes. Moreover, Suz12 −/− ES cells are impaired in proper differentiation, resulting in a lack of repression of ES cell markers as well as activation of differentiation-specific genes. Finally, we demonstrate that the PcGs are actively recruited to several genes during ES cell differentiation, which despite an increase in H3K27me3 levels is not always sufficient to prevent transcriptional activation. In summary, we demonstrate that Suz12 is required for the establishment of specific expression programs required for ES cell differentiation. Furthermore, we provide evidence that PcGs have different mechanisms to regulate transcription during cellular differentiation.

scholarly journals The topographical regulation of embryonic stem cell differentiation

2004 ◽  
Vol 359 (1446) ◽  
pp. 1009-1020 ◽  
Author(s):  
Patricia Murray ◽  
David Edgar
Keyword(s):  
Cell Differentiation ◽  
Es Cells ◽  
Embryonic Stem ◽  
Stem Cell Differentiation ◽  
The Body ◽  
Embryonic Stem Cell Differentiation ◽  
Es Cell ◽  
Mouse Es Cells ◽  
Intercellular Signalling ◽  
Potential Use

The potential use of pluripotent stem cells for tissue repair or replacement is now well recognized. While the ability of embryonic stem (ES) cells to differentiate into all cells of the body is undisputed, their use is currently restricted by our limited knowledge of the mechanisms controlling their differentiation. This review discusses recent work by ourselves and others investigating the intercellular signalling events that occur within aggregates of mouse ES cells. The work illustrates that the processes of ES cell differentiation, epithelialization and programmed cell death are dependent upon their location within the aggregates and coordinated by the extracellular matrix. Establishment of the mechanisms involved in these events is not only of use for the manipulation of ES cells themselves, but it also throws light on the ways in which differentiation is coordinated during embryogenesis.

scholarly journals Changes in the Distributions and Dynamics of Polycomb Repressive Complexes during Embryonic Stem Cell Differentiation

2008 ◽  
Vol 28 (9) ◽  
pp. 2884-2895 ◽  
Author(s):  
Xiaojun Ren ◽  
Claudius Vincenz ◽  
Tom K. Kerppola
Keyword(s):  
Cell Differentiation ◽  
Protein Localization ◽  
Es Cells ◽  
Embryonic Stem ◽  
Stem Cell Differentiation ◽  
Bimolecular Fluorescence Complementation ◽  
Global Changes ◽  
Embryonic Stem Cell Differentiation ◽  
Es Cell ◽  
A Genome

ABSTRACT Polycomb group (PcG) transcription regulatory proteins maintain cell identity by sustained repression of numerous genes. The differentiation of embryonic stem (ES) cells induces a genome-wide shift in PcG target gene expression. We investigated the effects of differentiation and protein interactions on CBX family PcG protein localization and dynamics by using fluorescence imaging. In mouse ES cells, different CBX proteins exhibited distinct distributions and mobilities. Most CBX proteins were enriched in foci known as Polycomb bodies. Focus formation did not affect CBX protein mobilities, and the foci dispersed during ES cell differentiation. The mobilities of CBX proteins increased upon the induction of differentiation and decreased as differentiation progressed. The deletion of the chromobox, which mediates interactions with RING1B, prevented the immobilization of CBX proteins. In contrast, the deletion of the chromodomain, which can bind trimethylated lysine 27 of histone H3, had little effect on CBX protein dynamics. The distributions and mobilities of most CBX proteins corresponded to those of CBX-RING1B complexes detected by using bimolecular fluorescence complementation analysis. Epigenetic reprogramming during ES cell differentiation is therefore associated with global changes in the subnuclear distributions and dynamics of CBX protein complexes.

A definitive role of Shp-2 tyrosine phosphatase in mediating embryonic stem cell differentiation and hematopoiesis

Blood ◽  
2003 ◽  
Vol 102 (6) ◽  
pp. 2074-2080 ◽  
Author(s):  
Rebecca J. Chan ◽  
Scott A. Johnson ◽  
Yanjun Li ◽  
Mervin C. Yoder ◽  
Gen-Sheng Feng
Keyword(s):  
Cell Differentiation ◽  
Embryoid Body ◽  
Es Cells ◽  
Tyrosine Phosphatase ◽  
Embryonic Stem ◽  
Stem Cell Differentiation ◽  
Initial Step ◽  
Embryonic Stem Cell Differentiation ◽  
Es Cell

Abstract Homozygous mutant (Shp-2Δ46-110) embryonic stem (ES) cells exhibit decreased hematopoiesis; however, the point at which Shp-2 is critical for ES cell differentiation to hematopoietic cells is unknown. We characterized the differentiation defect of Shp-2Δ46-110 ES cells by examining early points of differentiation, conducting leukemia inhibitory factor (LIF)–stimulated biochemical analysis, and performing in vitro reconstitution studies with wild-type (WT) Shp-2. ES cell in vitro differentiation assays were used to compare the differentiation of WT, Shp-2Δ46-110, and reconstituted ES cells to mesoderm, by measuring brachyury expression, to hemangioblasts, by measuring blast colony-forming cell (BL-CFC) formation and flk-1 expression, and to hematopoietic progenitor colony-forming cells, by performing secondary plating assays. LIF-stimulated phospho-Stat3 (known to be critical for ES cell self-renewal and maintenance of an undifferentiated state) and phospho-Erk levels were examined by immunoblotting. ES cell survival, using annexin V staining, and secondary embryoid body (EB) formation were also evaluated. Differentiation to both mesoderm and hemangioblasts was lower in Shp-2Δ46-110 cells compared to WT cells. On reconstitution with WT Shp-2, expression of brachyury and flk-1 and differentiation to hemangioblasts and primitive and definitive hematopoietic progenitors were restored. LIF-stimulated phospho-Stat3 levels were higher, whereas phospho-Erk levels were lower in Shp-2Δ46-110 ES cells than in WT and reconstituted cells. The increased phospho-Stat3 levels correlated with increased Shp-2Δ46-110 ES cell secondary EB formation and survival. We conclude that normal Shp-2 function is critical for the initial step of ES cell differentiation to mesoderm and to hemangioblasts and acts within the LIF-gp130-Stat3 pathway to maintain a proper balance of ES cell differentiation, pluripotency, and apoptosis.

scholarly journals Bivalent genes that undergo transcriptional switching identify networks of key regulators of embryonic stem cell differentiation

BMC Genomics ◽  
2020 ◽  
Vol 21 (S10) ◽  
Author(s):  
Ah-Jung Jeon ◽  
Greg Tucker-Kellogg
Keyword(s):  
Cell Differentiation ◽  
Time Series Data ◽  
Es Cells ◽  
Expression Patterns ◽  
Embryonic Stem ◽  
Stem Cell Differentiation ◽  
Chromatin State ◽  
Series Data ◽  
Embryonic Stem Cell Differentiation ◽  
Gene Promoters

Abstract Background Bivalent promoters marked with both H3K27me3 and H3K4me3 histone modifications are characteristic of poised promoters in embryonic stem (ES) cells. The model of poised promoters postulates that bivalent chromatin in ES cells is resolved to monovalency upon differntiation. With the availability of single-cell RNA sequencing (scRNA-seq) data, subsequent switches in transcriptional state at bivalent promoters can be studied more closely. Results We develop an approach for capturing genes undergoing transcriptional switching by detecting ‘bimodal’ gene expression patterns from scRNA-seq data. We integrate the identification of bimodal genes in ES cell differentiation with analysis of chromatin state, and identify clear cell-state dependent patterns of bimodal, bivalent genes. We show that binarization of bimodal genes can be used to identify differentially expressed genes from fractional ON/OFF proportions. In time series data from differentiating cells, we build a pseudotime approximation and use a hidden Markov model to infer gene activity switching pseudotimes, which we use to infer a regulatory network. We identify pathways of switching during differentiation, novel details of those pathway, and transcription factor coordination with downstream targets. Conclusions Genes with expression levels too low to be informative in conventional scRNA analysis can be used to infer transcriptional switching networks that connect transcriptional activity to chromatin state. Since chromatin bivalency is a hallmark of gene promoters poised for activity, this approach provides an alternative that complements conventional scRNA-seq analysis while focusing on genes near the ON/OFF boundary of activity. This offers a novel and productive means of inferring regulatory networks from scRNA-seq data.

scholarly journals MicroRNA-1 transfected embryonic stem cells enhance cardiac myocyte differentiation and inhibit apoptosis by modulating the PTEN/Akt pathway in the infarcted heart

2011 ◽  
Vol 301 (5) ◽  
pp. H2038-H2049 ◽  
Author(s):  
Carley Glass ◽  
Dinender K. Singla
Keyword(s):  
Cell Differentiation ◽  
Cardiac Myocyte ◽  
Heart Function ◽  
Es Cells ◽  
Embryonic Stem ◽  
Stem Cell Differentiation ◽  
Border Zone ◽  
Es Cell ◽  
Infarcted Heart ◽  
Myocyte Differentiation

microRNAs (miRs) have emerged as critical modulators of various physiological processes including stem cell differentiation. Indeed, miR-1 has been reported to play an integral role in the regulation of cardiac muscle progenitor cell differentiation. However, whether overexpression of miR-1 in embryonic stem (ES) cells (miR-1-ES cells) will enhance cardiac myocyte differentiation following transplantation into the infarcted myocardium is unknown. In the present study, myocardial infarction (MI) was produced in C57BL/6 mice by left anterior descending artery ligation. miR-1-ES cells, ES cells, or culture medium (control) was transplanted into the border zone of the infarcted heart, and 2 wk post-MI, cardiac myocyte differentiation, adverse ventricular remodeling, and cardiac function were assessed. We provide evidence demonstrating enhanced cardiac myocyte commitment of transplanted miR-1-ES cells in the mouse infarcted heart as compared with ES cells. Assessment of apoptosis revealed that overexpression of miR-1 in transplanted ES cells protected host myocardium from MI-induced apoptosis through activation of p-AKT and inhibition of caspase-3, phosphatase and tensin homolog, and superoxide production. A significant reduction in interstitial and vascular fibrosis was quantified in miR-1-ES cell and ES cell transplanted groups compared with control MI. However, no statistical significance between miR-1-ES cell and ES cell groups was observed. Finally, mice receiving miR-1-ES cell transplantation post-MI had significantly improved heart function compared with respective controls ( P < 0.05). Our data suggest miR-1 drives cardiac myocyte differentiation from transplanted ES cells and inhibits apoptosis post-MI, ultimately giving rise to enhanced cardiac repair, regeneration, and function.

Role of TPO in the Differentiation of Embryonic Stem Cells into Hematopoetic Cells.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4202-4202
Author(s):  
Zheng Wang ◽  
Pramono Andri ◽  
Skokowa Julia ◽  
Welte Karl
Keyword(s):  
Stem Cell ◽  
Cell Differentiation ◽  
Rhesus Monkey ◽  
Embryonic Stem Cell ◽  
Mrna Expression ◽  
Es Cells ◽  
Embryonic Stem ◽  
Stem Cell Differentiation ◽  
Embryonic Stem Cell Differentiation

Abstract Thrombopoetin (TPO) is a primary regulator of megakaryocyte and platelet production. However, studies in c-mpl-deficient mice and in congenital amegakaryocytic thrombocytopenia-patients with non-sense c-mpl mutation who develop pancytopenia during the first years of life suggest that TPO also play an important role on early hematopoesis. We demonstrated that TPO enhances FLK-1 (VEGF-receptor) expression on hemangioblasts during murine embryonic stem cell differentiation in embryoid body-liquid cultures (up to 73%). To extend our studies, we investigated the TPO signaling in FLK-1 positive cells. ES cells at different time point of differentiation showed that TPO enhances c-mpl-, BMP4-, Notch-, HOXB4-, HOXB9-, HOXA10-, Runx1-and CD133- mRNA expression. To investigate mesoderm formation, we also analyzed GATA-4 and T-brachyury mRNA level expression. Interestingly, we found that TPO alone did not increase GATA-4- and T-brachyury- mRNA expression, suggesting that TPO requires other cytokines to form the mesoderm. We also found that TPO could maintain VEGF-A mRNA expression level during differentiation of ES-cells. We hypothesize that VEGF expression together with c-mpl expression is required in hematopoetic differentiation of ES cell. This activity of Tpo was also observed during Rhesus monkey embryonic stem cell differentiation into hematopoetic cell. Only combinations of TPO and VEGF were capable of increasing CD34 positive hematopoietic progenitor cells (up to 8%), but TPO alone failed to induce high levels of CD34+ cell. In addition, analysis of gene expression during hemangioblast development demonstrated that TPO was capable of increasing the expression of VEGF receptors (FLK-1) and TPO receptors (c-mpl) in mice and primates. The in-vitro differentiation of mouse and rhesus monkey ES cells provides an opportunity to better understand the role of TPO in the early stage of hematopoietic development from ES cells to mature hematopoietic cells.

Transgenes Targeted to the HPRT Locus and Expressed from a Tetracycline-Inducible Promoter Are Silenced during Embryonic Stem Cell Differentiation.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3618-3618
Author(s):  
Laurie A. Milner ◽  
Michael Kyba ◽  
George Q. Daley ◽  
Marlene Balys
Keyword(s):  
Cell Differentiation ◽  
Chromatin Remodeling ◽  
Transgene Expression ◽  
Es Cells ◽  
Embryonic Stem ◽  
Stem Cell Differentiation ◽  
Embryoid Bodies ◽  
Open Chromatin ◽  
Rosa26 Locus ◽  
Hprt Locus

Abstract Genetic modification of embryonic stem (ES) cells provides a powerful system for the correlation of in vitro and in vivo gene function, an issue relevant to transplantation, gene therapy and tissue engineering. ES cells also present unique obstacles to genetic manipulation, particularly with regard to epigenetic modulation of transgene expression. Strategies used to circumvent problems associated with methylation, histone deactylation, and chromatin remodeling include modification of vector sequences, insulators, and targeting transgenes to sites of “open” chromatin structure. Systems combining gene targeting with non-viral promoters have shown particular promise. In these studies, a variety of transgenes were introduced into Ainv15 ES cells and doxycycline (dox)-induced expression evaluated by flow cytometry and quantitative PCR. Ainv ES cells express a reverse tetracycline transactivator (rtTA) from the ROSA26 locus and allow Cre-mediated insertion of transgenes into the HPRT locus adjacent to a tetracycline response element (TRE). As expected, transgene expression in undifferentiated ES cells could be regulated by dose and time of exposure to dox. However, expression levels varied dramatically for different transgenes; variability was transgene-specific and did not directly correlate with transgene size or the presence of YFP sequences. In addition, regardless of initial expression level, all transgenes were transcriptionally silenced during ES cell differentiation as embryoid bodies (EBs). Distinct patterns of silencing occurred when cells were induced for 24 hours immediately preceding analysis or continuously from the start of EB differentiation. In both cases, a pronounced loss of expression occurred between days 4–7; however, EBs treated with dox for 24 hours maintained a population of cells capable of maximal induction through day 6, whereas continuously treated cells showed a marked decline in this population by day 4. These results suggested two distinct processes: a primary loss of inducibility independent of dox exposure and a secondary refractoriness of expressing cells to reinduction. The reproducible patterns further suggested that loss of TRE activity or general silencing of the HPRT locus were responsible. To distinguish between these possibilities, expression of HPRT and NeoR, which flank transgenes in targeted Ainv cells, were evaluated. In contrast to the loss of transgene expression, HPRT and NeoR expression remained stable or increased between EB day 3–7, indicating that silencing was not due to general chromatin remodeling within the locus. Expression of rtTA was also stable, excluding the possibility that silencing of the ROSA26 locus was responsible. We conclude that silencing in this system is due to a loss of TRE activity between EB days 4–7, and speculate that inhibitory factors produced by ES cells at this stage of differentiation are responsible. The findings underscore the complexities of gene regulation in ES cells, and raise the possibility that the capacity of cells to express transgenes may in part reflect intrinsic cell potential. In addition, if cells of particular lineages produce factors that interfere with TRE activity, there are obvious implications for using the Tet-On system for inducing gene expression in those lineages.

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