182. NOVEL SIGNALLING IN MOUSE EMBRYONIC STEM CELLS GENERATES PRIMITIVE ECTODERM-LIKE CELLS

2009 ◽  
Vol 21 (9) ◽  
pp. 100
Author(s):  
M. B. Morris ◽  
N. Hamra ◽  
A. C. Lonic ◽  
F. Felquer
Keyword(s):  
Es Cells ◽  
Embryonic Stem ◽  
Cell Types ◽  
Leukaemia Inhibitory Factor ◽  
Signalling Pathways ◽  
Specific Cell ◽  
Self Renewal ◽  
Mouse Es Cells ◽  
Homogeneous Production ◽  
Extracellular Molecules

The phenotypic status of embryonic stem (ES) cells is controlled in part by signalling pathways which translate inputs mediated by extracellular molecules. An important extracellular protagonist in mouse ES cells is LIF (leukaemia inhibitory factor) which interacts with the gp130–LIFR receptor complex to activate a number of downstream signalling pathways, including the STAT3, MEK/ERK and PI3K/Akt. These pathways, together with others, interact in complex and sometimes competing ways to generate the well-known characteristics of mouse ES cells of self-renewal, high rates of proliferation, and pluripotence. The addition of a second molecule, L-proline, to the extracellular environment alters the pluripotent status of mouse ES cells, converting them to a second pluripotent population equivalent to the primitive ectoderm of the pre-gastrulating embryo. This conversion, from ES cells to primitive ectoderm-like cells, primes the latter for directed differentiation to specific cell types (1). Here we show, using inhibitor studies and kinome array analysis, that this small molecule appears to work by (i) changing the balance in activity of signalling pathways already stimulated by LIF and (ii) activating additional signalling pathways. Specifically, L-proline rapidly further activates the LIF-stimulated MEK/ERK pathway, tipping the balance in favour of primitive-ectoderm formation and away from ES-cell self-renewal sustained by LIF-mediated activation of the STAT3 pathway. In addition, L-proline rapidly stimulates other pathways including p38, mTOR and PI3K/Akt each of which contributes, to a greater or lesser extent, to the conversion to primitive ectoderm-like cells. These results indicate that (i) L-proline acts in novel ways to stimulate embryo-like developmental progression in ES cells and (ii) through the addition of small, nontoxic activators and inhibitors of signalling pathways, the differentiation of pluripotent ES cells might be controlled sufficiently well for the homogeneous production of specific cell types suitable for use in animal models of human disease.

scholarly journals T-type Ca2+ channels in mouse embryonic stem cells: modulation during cell cycle and contribution to self-renewal

2012 ◽  
Vol 302 (3) ◽  
pp. C494-C504 ◽  
Author(s):  
José A. Rodríguez-Gómez ◽  
Konstantín L. Levitsky ◽  
José López-Barneo
Keyword(s):  
Cell Cycle ◽  
Alkaline Phosphatase ◽  
Es Cells ◽  
Embryonic Stem ◽  
Cell Types ◽  
Mrna Levels ◽  
Es Cell ◽  
External Application ◽  
Self Renewal ◽  
Mouse Es Cells

Ion channels participate in cell homeostasis and are involved in the regulation of proliferation and differentiation in several cell types; however, their presence and function in embryonic stem (ES) cells are poorly studied. We have investigated the existence of voltage-dependent inward currents in mouse ES cells and their ability to modulate proliferation and self-renewal. Patch-clamped ES cells had inactivating tetrodotoxin (TTX)-sensitive Na+ currents as well as transient Ca2+ currents abolished by the external application of Ni2+. Biophysical and pharmacological data indicated that the Ca2+ current is predominantly mediated by T-type (Cav3.2) channels. The number of cells expressing T-type channels and Cav3.2 mRNA levels increased at the G1/S transition of the cell cycle. TTX had no effect on ES cell proliferation. However, blockade of T-type Ca2+ currents with Ni2+ induced a decrease in proliferation and alkaline phosphatase positive colonies as well as reduced expression of Oct3/4 and Nanog, all indicative of loss in self-renewal capacity. Decreased alkaline phosphatase and Oct3/4 expression were also observed in cells subjected to small interfering RNA-induced knockdown for T-type (Cav3.2) Ca2+ channels, thus partially recapitulating the pharmacological effects on self-renewal. These results indicate that Cav3.2 channel expression in ES cells is modulated along the cell cycle being induced at late G1 phase. They also suggest that these channels are involved in the maintenance of the undifferentiated state of mouse ES cells. We propose that Ca2+ entry mediated by Cav3.2 channels might be one of the intracellular signals that participate in the complex network responsible for ES cell self-renewal.

Tyrosine kinase signalling in embryonic stem cells

2008 ◽  
Vol 115 (2) ◽  
pp. 43-55 ◽  
Author(s):  
Cecilia Annerén
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Tyrosine Kinase ◽  
Tyrosine Kinases ◽  
Es Cells ◽  
Embryonic Stem ◽  
Cell Types ◽  
Self Renewal ◽  
Mouse Es Cells ◽  
Wide Range

Pluripotent ES (embryonic stem) cells can be expanded in culture and induced to differentiate into a wide range of cell types. Self-renewal of ES cells involves proliferation with concomitant suppression of differentiation. Some critical and conserved pathways regulating self-renewal in both human and mouse ES cells have been identified, but there is also evidence suggesting significant species differences. Cytoplasmic and receptor tyrosine kinases play important roles in proliferation, survival, self-renewal and differentiation in stem, progenitor and adult cells. The present review focuses on the role of tyrosine kinase signalling for maintenance of the undifferentiated state, proliferation, survival and early differentiation of ES cells.

Transcription factors that behave as master regulators during mammalian embryogenesis function as molecular rheostats

2008 ◽  
Vol 411 (2) ◽  
pp. e5-e7 ◽  
Author(s):  
Angie Rizzino
Keyword(s):  
Transcription Factors ◽  
Molecular Mechanisms ◽  
Es Cells ◽  
Embryonic Stem ◽  
Special Property ◽  
The Self ◽  
Leukaemia Inhibitory Factor ◽  
Self Renewal ◽  
Master Regulators ◽  
Mammalian Embryogenesis

Three transcription factors, Sox2, Oct-3/4 and Nanog, have been identified as master regulators that orchestrate mammalian embryogenesis as well as the self-renewal and pluripotency of ES (embryonic stem) cells. Efforts to understand how these transcription factors function have shown that they have a special property in common. Small changes in the expression of any one of these factors dramatically alter the self-renewal and pluripotency of ES cells. In this way, each functions as a molecular rheostat to control the behaviour of ES cells. Recent studies have begun to examine the molecular mechanisms that regulate the levels of these transcription factors. In this issue of the Biochemical Journal, Mullin and co-workers report that Nanog can self-associate to form dimers. Importantly, they also show that the domain responsible for dimerization is also needed for Nanog to sustain the self-renewal of ES cells in the absence of the cytokine LIF (leukaemia inhibitory factor). On the basis of their studies, they propose a novel mechanism for regulating the interactions between Nanog and other nuclear proteins.

The WNT receptor FZD7 contributes to self-renewal signaling of human embryonic stem cells

2008 ◽  
Vol 389 (7) ◽  
Author(s):  
Kai Melchior ◽  
Jonathan Weiß ◽  
Holm Zaehres ◽  
Yong-mi Kim ◽  
Carolyn Lutzko ◽  
...  
Keyword(s):  
Es Cells ◽  
Embryonic Stem ◽  
Cell Types ◽  
Marker Genes ◽  
Specific Marker ◽  
Mrna Levels ◽  
Es Cell ◽  
Specific Expression ◽  
Self Renewal ◽  
Human Es Cells

Abstract A number of recent studies identified nuclear factors that together have the unique ability to induce pluripotency in differentiated cell types. However, little is known about the factors that are needed to maintain human embryonic stem (ES) cells in an undifferentiated state. In a search for such requirements, we performed a comprehensive meta-analysis of publicly available SAGE and microarray data. The rationale for this analysis was to identify genes that are exclusively expressed in human ES cell lines compared to 30 differentiated tissue types. The WNT receptor FZD7 was found among the genes with an ES cell-specific expression profile in both SAGE and microarray analyses. Subsequent validation by quantitative RT-PCR and flow cytometry confirmed that FZD7 mRNA levels in human ES cells are up to 200-fold higher compared to differentiated cell types. ShRNA-mediated knockdown of FZD7 in human ES cells induced dramatic changes in the morphology of ES cell colonies, perturbation of expression levels of germ layer-specific marker genes, and a rapid loss of expression of the ES cell-specific transcription factor OCT4. These findings identify the WNT receptor FZD7 as a novel ES cell-specific surface antigen with a likely important role in the maintenance of ES cell self-renewal capacity.

Role of the phosphoinositide 3-kinase pathway in mouse embryonic stem (ES) cells

2005 ◽  
Vol 33 (6) ◽  
pp. 1522-1525 ◽  
Author(s):  
K. Takahashi ◽  
M. Murakami ◽  
S. Yamanaka
Keyword(s):  
Es Cells ◽  
Mammalian Target Of Rapamycin ◽  
Embryonic Stem ◽  
Pi3k Pathway ◽  
Leukaemia Inhibitory Factor ◽  
Mouse Es Cells ◽  
Ras Family ◽  
Phosphoinositide 3 Kinase ◽  
Kinase Pathway

Mouse ES (embryonic stem) cells maintain pluripotency with robust proliferation in vitro. ES cells share some similarities with cancer cells, such as anchorage-independent growth, loss of contact inhibition and tumour formation. After differentiation, ES cells lose pluripotency and tumorigenicity. Recent studies showed that the PI3K (phosphoinositide 3-kinase) pathway is important for proliferation, survival and maintenance of pluripotency in ES cells. The PI3K pathway is activated by growth factors and cytokines including insulin and leukaemia inhibitory factor. In addition to these exogenous factors, the PI3K pathway is endogenously activated by the constitutively active Ras family protein ERas (ES cell-expressed Ras). The PI3K pathway utilizes multiple downstream effectors including mTOR (mammalian target of rapamycin), which we have shown to be essential for proliferation in mouse ES cells and early embryos.

Expression of dopamine and adrenergic receptors in mouse embryonic stem cells and preimplantation embryos

Biologia ◽  
2015 ◽  
Vol 70 (9) ◽  
pp. 1263-1271 ◽  
Author(s):  
Štefan Čikoš ◽  
Dušan Fabian ◽  
Ján Burkuš ◽  
Žofia Janštová ◽  
Juraj Koppel
Keyword(s):  
Dopamine Receptor ◽  
Adrenergic Receptors ◽  
Developmental Stages ◽  
Expression Profiles ◽  
Es Cells ◽  
Embryonic Stem ◽  
Cell Types ◽  
Preimplantation Embryos ◽  
Receptor Subtypes ◽  
Mouse Es Cells

Abstract Using RT-PCR we examined expression of dopamine and adrenergic receptors in undifferentiated and spontaneously differentiating mouse embryonic stem (ES) cells. We also examined expression of dopamine receptor subtypes in mouse ovulated oocytes and preimplantation embryos. Comparing the expression of catecholamine receptors in undifferentiated mouse ES cells and in blastocysts (from which ES cells are derived), we found that transcripts of all five dopamine receptors were expressed in both cell types. In contrast, we detected eight adrenergic receptor subtypes in undifferentiated mouse ES cells, but only three subtypes were found in mouse blastocysts. In three adrenergic receptors (α1D, α2B, β1), we found higher expression in the spontaneously differentiating ES cells than in undifferentiated ES cells, and the α1B adrenoceptor was not even detectable in the undifferentiated cells. These results indicate that genes encoding all types of catecholamine receptors are transcribed in mouse ES cells, and some of them are differentially expressed during ES cell differentiation. We found several profiles of dopamine receptor mRNA expression during the preimplantation period. The DR3 transcript was present in all examined stages (oocytes, 4-cell embryos, 8- to 16-cell embryos, blastocysts). DR1 and DR4 transcripts were not found in oocytes, but we detected them in preimplantation embryos. The DR2 receptor transcript was found in all examined stages except for the 4-cell embryos, and the DR5 receptor transcript was found in all examined stages except for the 8- to 16-cell embryos. The expression profiles of dopamine receptor transcripts suggest different roles of some receptor subtypes in particular preimplantation developmental stages.

scholarly journals SC1 Promotes MiR124-3p Expression to Maintain the Self-Renewal of Mouse Embryonic Stem Cells by Inhibiting the MEK/ERK Pathway

2017 ◽  
Vol 44 (5) ◽  
pp. 2057-2072 ◽  
Author(s):  
Qing Wei ◽  
Hongliang Liu ◽  
Zhiying Ai ◽  
Yongyan Wu ◽  
Yingxiang Liu ◽  
...  
Keyword(s):  
Deep Sequencing ◽  
Small Rna ◽  
Es Cells ◽  
Embryonic Stem ◽  
The Self ◽  
Erk Pathway ◽  
Self Renewal ◽  
Mouse Es Cells ◽  
Rna Deep Sequencing ◽  
Small Rna Deep Sequencing

Background/Aims: Self-renewal is one of the most important features of embryonic stem (ES) cells. SC1 is a small molecule modulator that effectively maintains the self-renewal of mouse ES cells in the absence of leukemia inhibitory factor (LIF), serum and feeder cells. However, the mechanism by which SC1 maintains the undifferentiated state of mouse ES cells remains unclear. Methods: In this study, microarray and small RNA deep-sequencing experiments were performed on mouse ES cells treated with or without SC1 to identify the key genes and microRNAs that contributed to self-renewal. Results: SC1 regulates the expressions of pluripotency and differentiation factors, and antagonizes the retinoic acid (RA)-induced differentiation in the presence or absence of LIF. SC1 inhibits the MEK/ERK pathway through Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis and pathway reporting experiments. Small RNA deep-sequencing revealed that SC1 significantly modulates the expression of multiple microRNAs with crucial functions in ES cells. The expression of miR124-3p is upregulated in SC1-treated ES cells, which significantly inhibits the MEK/ERK pathway by targeting Grb2, Sos2 and Egr1. Conclusion: SC1 enhances the self-renewal capacity of mouse ES cells by modulating the expression of key regulatory genes and pluripotency-associated microRNAs. SC1 significantly upregulates miR124-3p expression to further inhibit the MEK/ ERK pathway by targeting Grb2, Sos2 and Egr1.

scholarly journals Glycosaminoglycans as regulators of stem cell differentiation

2011 ◽  
Vol 39 (1) ◽  
pp. 383-387 ◽  
Author(s):  
Raymond A.A. Smith ◽  
Kate Meade ◽  
Claire E. Pickford ◽  
Rebecca J. Holley ◽  
Catherine L.R. Merry
Keyword(s):  
Stem Cell ◽  
Cell Differentiation ◽  
Es Cells ◽  
Three Dimensional ◽  
Embryonic Stem ◽  
Stem Cell Differentiation ◽  
Cell Types ◽  
Specific Pattern ◽  
Embryonic Stem Cell Differentiation ◽  
Specific Cell

ES (embryonic stem) cell differentiation is dependent on the presence of HS (heparan sulfate). We have demonstrated that, during differentiation, the evolution of specific cell lineages is associated with particular patterns of GAG (glycosaminoglycan) expression. For example, different HS epitopes are synthesized during neural or mesodermal lineage formation. Cell lines mutant for various components of the HS biosynthetic pathway are selectively impaired in their differentiation, with lineage-specific effects observed for some lines. We have also observed that the addition of soluble GAG saccharides to cells, with or without cell-surface HS, can influence the pace and outcome of differentiation, again highlighting specific pattern requirements for particular lineages. We are combining this work with ongoing studies into the design of artificial cell environments where we have optimized three-dimensional scaffolds, generated by electrospinning or by the formation of hydrogels, for the culture of ES cells. By permeating these scaffolds with defined GAG oligosaccharides, we intend to control the mechanical environment of the cells (via the scaffold architecture) as well as their biological signalling environment (using the oligosaccharides). We predict that this will allow us to control ES cell pluripotency and differentiation in a three-dimensional setting, allowing the generation of differentiated cell types for use in drug discovery/testing or in therapeutics.

scholarly journals UTF1 is a chromatin-associated protein involved in ES cell differentiation

2007 ◽  
Vol 178 (6) ◽  
pp. 913-924 ◽  
Author(s):  
Vincent van den Boom ◽  
Susanne M. Kooistra ◽  
Marije Boesjes ◽  
Bart Geverts ◽  
Adriaan B. Houtsmuller ◽  
...  
Keyword(s):  
Cell Differentiation ◽  
Leucine Zipper ◽  
Es Cells ◽  
Embryonic Stem ◽  
Cell Types ◽  
Embryonic Cell ◽  
Es Cell ◽  
Self Renewal ◽  
Adult Cell ◽  
Core Histones

Embryonic stem (ES) cells are able to grow indefinitely (self-renewal) and have the potential to differentiate into all adult cell types (pluripotency). The regulatory network that controls pluripotency is well characterized, whereas the molecular basis for the transition from self-renewal to the differentiation of ES cells is much less understood, although dynamic epigenetic gene silencing and chromatin compaction are clearly implicated. In this study, we report that UTF1 (undifferentiated embryonic cell transcription factor 1) is involved in ES cell differentiation. Knockdown of UTF1 in ES and carcinoma cells resulted in a substantial delay or block in differentiation. Further analysis using fluorescence recovery after photobleaching assays, subnuclear fractionations, and reporter assays revealed that UTF1 is a stably chromatin-associated transcriptional repressor protein with a dynamic behavior similar to core histones. An N-terminal Myb/SANT domain and a C-terminal domain containing a putative leucine zipper are required for these properties of UTF1. These data demonstrate that UTF1 is a strongly chromatin-associated protein involved in the initiation of ES cell differentiation.

scholarly journals Regulation of embryonic stem cell self-renewal and pluripotency by leukaemia inhibitory factor

2011 ◽  
Vol 438 (1) ◽  
pp. 11-23 ◽  
Author(s):  
Hiroyuki Hirai ◽  
Peter Karian ◽  
Nobuaki Kikyo
Keyword(s):  
Stem Cells ◽  
Embryonic Stem ◽  
Gene Expression Pattern ◽  
Receptor Activation ◽  
Janus Kinase ◽  
Inhibitory Factor ◽  
Mitogen Activated Protein Kinase ◽  
Leukaemia Inhibitory Factor ◽  
Signalling Pathways ◽  
Self Renewal

LIF (leukaemia inhibitory factor) is a key cytokine for maintaining self-renewal and pluripotency of mESCs (mouse embryonic stem cells). Upon binding to the LIF receptor, LIF activates three major intracellular signalling pathways: the JAK (Janus kinase)/STAT3 (signal transducer and activator of transcription 3), PI3K (phosphoinositide 3-kinase)/AKT and SHP2 [SH2 (Src homology 2) domain-containing tyrosine phosphatase 2]/MAPK (mitogen-activated protein kinase) pathways. These pathways converge to orchestrate the gene expression pattern specific to mESCs. Among the many signalling events downstream of the LIF receptor, activation and DNA binding of the transcription factor STAT3 plays a central role in transducing LIF's functions. The fundamental role of LIF for pluripotency was highlighted further by the discovery that LIF accelerates the conversion of epiblast-derived stem cells into a more fully pluripotent state. In the present review, we provide an overview of the three major LIF signalling pathways, the molecules that interact with STAT3 and the current interpretations of the roles of LIF in pluripotency.

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