scholarly journals FGF/MAPK signaling sets the switching threshold of a bistable circuit controlling cell fate decisions in ES cells

2015 ◽  
Author(s):  
Christian Schröter ◽  
Pau Rué ◽  
Jonathan P Mackenzie ◽  
Alfonso Martinez Arias
Keyword(s):  
Cell Fate ◽  
Network Architecture ◽  
Cell Model ◽  
Es Cells ◽  
Embryonic Stem ◽  
Transcriptional Regulators ◽  
Mapk Signaling ◽  
Threshold Concentration ◽  
Cell Fates ◽  
Cell Fate Decisions

Intracellular transcriptional regulators and extracellular signaling pathways together regulate the allocation of cell fates during development, but how their molecular activities are integrated to establish the correct proportions of cells with particular fates is not known. Here we study this question in the context of the decision between the epiblast (Epi) and the primitive endoderm (PrE) fate that occurs in the mammalian preimplantation embryo. Using an embryonic stem (ES) cell model, we discover two successive functions of FGF/MAPK signaling in this decision. First, the pathway needs to be inhibited to make the PrE-like gene expression program accessible for activation by GATA transcription factors in ES cells. In a second step, MAPK signaling levels determine the threshold concentration of GATA factors required for PrE-like differentiation, and thereby control the proportion of cells differentiating along this lineage. Our findings can be explained by a simple mutual repression circuit modulated by FGF/MAPK signaling. This may be a general network architecture to integrate the activity of signal transduction pathways and transcriptional regulators, and serve to balance proportions of cell fates in several contexts.

scholarly journals Endogenous fluctuations of OCT4 and SOX2 bias pluripotent cell fate decisions

2018 ◽  
Author(s):  
Daniel Strebinger ◽  
Cédric Deluz ◽  
Elias T. Friman ◽  
Subashika Govindan ◽  
Andrea B. Alber ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Cell Fate ◽  
Es Cells ◽  
Embryonic Stem ◽  
Chromatin Accessibility ◽  
Directed Differentiation ◽  
Es Cell ◽  
Endogenous Fluctuations ◽  
Cell Fate Decisions ◽  
Oct4 Protein

AbstractSOX2 and OCT4 are pioneer transcription factors playing a key role in embryonic stem (ES) cell self-renewal and differentiation. However, how temporal fluctuations in their expression levels bias lineage commitment is unknown. Here we generated knock-in reporter fusion ES cell lines allowing to monitor endogenous SOX2 and OCT4 protein fluctuations in living cells and to determine their impact on mesendodermal and neuroectodermal commitment. We found that small differences in SOX2 and OCT4 levels impact cell fate commitment in G1 but not in S phase. Elevated SOX2 levels modestly increased neuroectodermal commitment and decreased mesendodermal commitment upon directed differentiation. In contrast, elevated OCT4 levels strongly biased ES cell towards both neuroectodermal and mesendodermal fates. Using ATAC-seq on ES cells gated for different endogenous SOX2 and OCT4 levels, we found that high OCT4 levels increased chromatin accessibility at differentiation-associated enhancers. This suggests that small endogenous fluctuations of pioneer transcription factors can bias cell fate decisions by concentration-dependent priming of differentiation-associated enhancers.

scholarly journals Arkadia via SNON enables NODAL-SMAD2/3 signaling effectors to transcribe different genes depending on their levels

2018 ◽  
Author(s):  
Jonathon M. Carthy ◽  
Marilia Ioannou ◽  
Vasso Episkopou
Keyword(s):  
Cell Fate ◽  
Target Genes ◽  
Embryonic Stem ◽  
Null Mouse ◽  
Specific Cell ◽  
Cell Fates ◽  
Mammalian Embryo ◽  
Cell Fate Decisions ◽  
Dependent Cell ◽  
Anterior Posterior

AbstractHow cells assess levels of signaling and select to transcribe different target genes depending on the levels of activated effectors remains elusive. High NODAL-signalling levels specify anterior/head, lower specify posterior, and complete loss abolishes anterior-posterior patterning in the mammalian embryo. Here we show that cells assess NODAL-activated SMAD2 and SMAD3 (SMAD2/3) effector-levels by complex formation and pairing each effector with the co-repressor SNON, which is present in the cell before signaling. These complexes enable the E3-ubiquitin ligase Arkadia (RNF111) to degrade SNON. High SMAD2/3 levels can saturate and remove SNON, leading to derepression and activation of a subset of targets (high targets) that are highly susceptible to SNON repression. However, low SMAD2/3 levels can only reduce SNON preventing derepression/activation of high targets. Arkadia degrades SNON transiently only upon signaling exposure, leading to dynamic signaling-responses, which most likely initiate level-specific cell-fate decisions. Arkadia-null mouse embryos and Embryonic Stem Cells (ESC) cannot develop anterior tissues and head. However, SnoN/Arkadia, double-null embryos and ESCs are rescued confirming that Arkadia removes SNON, to achieve level-dependent cell-fatesOne Sentence SummarySignaling intensity induces equivalent degradation of a transcriptional repressor leading to level-dependent responses.

scholarly journals Cleavage of histone H2A during embryonic stem cell differentiation destabilizes nucleosomes to counteract gene activation

2021 ◽  
Author(s):  
Mariel Coradin ◽  
Joseph Cesare ◽  
Yemin Lan ◽  
Zhexin Zhu ◽  
Peder J. Lund ◽  
...  
Keyword(s):  
Cell Fate ◽  
Es Cells ◽  
Expression Patterns ◽  
Gene Activation ◽  
Embryonic Stem ◽  
Maximum Level ◽  
Stem Cell Differentiation ◽  
Embryonic Stem Cell Differentiation ◽  
Cell Fate Decisions ◽  
Lysosomal Protease

Histone proteolysis is a poorly understood phenomenon in which the N-terminal tails of histones are irreversibly cleaved by intracellular proteases. During development, histone post-translational modifications are known to orchestrate gene expression patterns that ultimately drive cell fate decisions. Therefore, deciphering the mechanisms of histone proteolysis is necessary to enhance the understanding of cellular differentiation. Here we show that H2A is cleaved by the lysosomal protease Cathepsin L during ESCs differentiation. Using quantitative mass spectrometry (MS), we identified L23 to be the primary cleavage site that gives rise to the clipped form of H2A (cH2A), which reaches a maximum level of ~1% of total H2A after four days of differentiation. Using ChIP-seq, we found that preventing proteolysis leads to an increase in acetylated H2A at promoter regions in differentiated ES cells. We also report the identification of novel readers of acetylated H2A in pluripotent ES cells, including members of the PBAF remodeling complex, which can recognize different acetylated forms of H2A. Finally, we show that H2A proteolysis abolishes this recognition. Altogether, our data suggests that proteolysis serves as an efficient mechanism to silence pluripotency genes and destabilize the nucleosome core particle.

scholarly journals An interplay between extracellular signalling and the dynamics of the exit from pluripotency drives cell fate decisions in mouse ES cells

2013 ◽  
Author(s):  
David A Turner ◽  
Jamie Trott ◽  
Penelope Hayward ◽  
Pau Rué ◽  
Alfonso Martinez Arias
Keyword(s):  
Cell Fate ◽  
Neural Development ◽  
Es Cells ◽  
Initial Period ◽  
Embryonic Stem ◽  
Primitive Streak ◽  
Wnt Signalling ◽  
Dependent Manner ◽  
Cell Fate Decisions ◽  
Mouse Es Cells

Embryonic Stem cells derived from the epiblast tissue of the mammalian blastocyst retain the capability to differentiate into any adult cell type and are able to self-renew indefinitely under appropriate culture conditions. Despite the large amount of knowledge that we have accumulated to date about the regulation and control of self-renewal, efficient directed differentiation into specific tissues remains elusive. In this work, we have analysed in a systematic manner the interaction between the dynamics of loss of pluripotency and Activin/Nodal, BMP4 and Wnt signalling in fate assignment during the early stages of differentiation of mouse ES cells in culture. During the initial period of differentiation, cells exit from pluripotency and enter an Epi-like state. Following this transient stage, and under the influence of Activin/Nodal and BMP signalling, cells face a fate choice between differentiating into neuroectoderm and contributing to Primitive Streak fates. We find that Wnt signalling does not suppress neural development as previously thought and that it aids both fates in a context dependent manner. Our results suggest that as cells exit pluripotency they are endowed with a primary neuroectodermal fate and that the potency to become endomesodermal rises with time. We suggest that this situation translates into a ?race for fates? in which the neuroectodermal fate has an advantage.

scholarly journals Morphogen dynamics control patterning in a stem cell model of the human embryo

2017 ◽  
Author(s):  
Idse Heemskerk ◽  
Kari Burt ◽  
Matthew Miller ◽  
Sapna Chhabra ◽  
M. Cecilia Guerra ◽  
...  
Keyword(s):  
Stem Cell ◽  
Cell Differentiation ◽  
Cell Fate ◽  
Human Embryo ◽  
Cell Model ◽  
Stem Cell Differentiation ◽  
Concentration Increase ◽  
Cell Fates ◽  
Cell Fate Decisions ◽  
Stem Cell Model

During embryonic development, diffusible signaling molecules called morphogens are thought to determine cell fates in a concentration-dependent manner1–4, and protocols for directed stem cell differentiation are based on this picture5–8. However, in the mammalian embryo, morphogen concentrations change rapidly compared to the time for making cell fate decisions9–12. It is unknown how changing ligand levels are interpreted, and whether the precise timecourse of ligand exposure plays a role in cell fate decisions. Nodal and BMP4 are morphogens crucial for gastrulation in vertebrates13. Each pathway has distinct receptor complexes that phosphorylate specific signal transducers, known as receptor-Smads, which then complex with the shared cofactor Smad4 to activate target genes14. Here we show in human embryonic stem cells (hESCs) that the response to BMP4 signaling indeed is determined by the ligand concentration, but that unexpectedly, the expression of many mesodermal targets of Activin/Nodal depends on rate of concentration increase. In addition, we use live imaging of hESCs with GFP integrated at the endogenous SMAD4 locus to show that a stem cell model for the human embryo15 generates a wave of Nodal signaling. Cells experience rapidly increasing Nodal specifically in the region of mesendoderm differentiation. We also demonstrate that pulsatile stimulation with Activin induces repeated strong signaling and enhances mesoderm differentiation. Our results break with the paradigm of concentration-dependent differentiation and demonstrate an important role for morphogen dynamics in the cell fate decisions associated with mammalian gastrulation. They suggest a highly dynamic picture of embryonic patterning where some cell fates depend on rapid concentration increase rather than absolute levels, and point to ligand dynamics as a new dimension to optimize protocols for directed stem cell differentiation.

scholarly journals FGF/MAPK signaling sets the switching threshold of a bistable circuit controlling cell fate decisions in embryonic stem cells

Development ◽  
2015 ◽  
Vol 142 (24) ◽  
pp. 4205-4216 ◽  
Author(s):  
C. Schro ter ◽  
P. Rue ◽  
J. P. Mackenzie ◽  
A. Martinez Arias
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Cell Fate ◽  
Embryonic Stem ◽  
Mapk Signaling ◽  
Cell Fate Decisions ◽  
Switching Threshold

scholarly journals Embryonic stem cells become mechanoresponsive upon exit from ground state of pluripotency

Open Biology ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 180203 ◽  
Author(s):  
C. M. Verstreken ◽  
C. Labouesse ◽  
C. C. Agley ◽  
K. J. Chalut
Keyword(s):  
Mechanical Stress ◽  
Cell Fate ◽  
Ground State ◽  
Es Cells ◽  
Embryonic Stem ◽  
Cell Fate Decisions ◽  
Mechanical Signals ◽  
Broad Array ◽  
Transcriptional Changes ◽  
The Impact

Stem cell fate decisions are driven by a broad array of signals, both chemical and mechanical. Although much progress has been made in our understanding of the impact of chemical signals on cell fate choice, much less is known about the role and influence of mechanical signalling, particularly in embryonic stem (ES) cells. Many studies use substrates with different stiffness to study mechanical signalling, but changing substrate stiffness can induce secondary effects which are difficult to disentangle from the direct effects of forces/mechanical signals. To probe the direct impact of mechanical stress on cells, we developed an adaptable cell substrate stretcher to exert specific, reproducible forces on cells. Using this device to test the response of ES cells to tensile strain, we found that cells experienced a transient influx of calcium followed by an upregulation of the so-called immediate and early genes. On longer time scales, however, ES cells in ground state conditions were largely insensitive to mechanical stress. Nonetheless, as ES cells exited the ground state, their susceptibility to mechanical signals increased, resulting in broad transcriptional changes. Our findings suggest that exit from ground state of pluripotency is unaffected by mechanical signals, but that these signals could become important during the next stage of lineage specification. A better understanding of this process could improve our understanding of cell fate choice in early development and improve protocols for differentiation guided by mechanical cues.

scholarly journals Drosophila Notch receptor activity suppresses Hairless function during adult external sensory organ development.

Genetics ◽  
1995 ◽  
Vol 141 (4) ◽  
pp. 1491-1505
Author(s):  
D F Lyman ◽  
B Yedvobnick
Keyword(s):  
Cell Fate ◽  
Daughter Cell ◽  
Notch Receptor ◽  
Sensory Organ ◽  
Cell Fates ◽  
Gain Of Function ◽  
Over Expression ◽  
Cell Fate Decisions ◽  
Synergistic Enhancement ◽  
Conditional Expression

Abstract The neurogenic Notch locus of Drosophila encodes a receptor necessary for cell fate decisions within equivalence groups, such as proneural clusters. Specification of alternate fates within clusters results from inhibitory communication among cells having comparable neural fate potential. Genetically, Hairless (H) acts as an antagonist of most neurogenic genes and may insulate neural precursor cells from inhibition. H function is required for commitment to the bristle sensory organ precursor (SOP) cell fate and for daughter cell fates. Using Notch gain-of-function alleles and conditional expression of an activated Notch transgene, we show that enhanced signaling produces H-like loss-of-function phenotypes by suppressing bristle SOP cell specification or by causing an H-like transformation of sensillum daughter cell fates. Furthermore, adults carrying Notch gain of function and H alleles exhibit synergistic enhancement of mutant phenotypes. Over-expression of an H+ transgene product suppressed virtually all phenotypes generated by Notch gain-of-function genotypes. Phenotypes resulting from over-expression of the H+ transgene were blocked by the Notch gain-of-function products, indicating a balance between Notch and H activity. The results suggest that H insulates SOP cells from inhibition and indicate that H activity is suppressed by Notch signaling.

scholarly journals Context-dependent roles of YAP/TAZ in stem cell fates and cancer

2021 ◽  
Author(s):  
Lucy LeBlanc ◽  
Nereida Ramirez ◽  
Jonghwan Kim
Keyword(s):  
Stem Cell ◽  
Cell Fate ◽  
Control Cell ◽  
Substantial Portion ◽  
Cell Fates ◽  
Cell Fate Decisions ◽  
Cell Death Pathways ◽  
Multiple Context ◽  
Cancer Cell Survival ◽  
Context Dependent

AbstractHippo effectors YAP and TAZ control cell fate and survival through various mechanisms, including transcriptional regulation of key genes. However, much of this research has been marked by conflicting results, as well as controversy over whether YAP and TAZ are redundant. A substantial portion of the discordance stems from their contradictory roles in stem cell self-renewal vs. differentiation and cancer cell survival vs. apoptosis. In this review, we present an overview of the multiple context-dependent functions of YAP and TAZ in regulating cell fate decisions in stem cells and organoids, as well as their mechanisms of controlling programmed cell death pathways in cancer.

Human embryonic stem cells: challenges and opportunities

2006 ◽  
Vol 18 (8) ◽  
pp. 839 ◽  
Author(s):  
Steven L. Stice ◽  
Nolan L. Boyd ◽  
Sujoy K. Dhara ◽  
Brian A. Gerwe ◽  
David W. Machacek ◽  
...  
Keyword(s):  
Stem Cells ◽  
Neural Stem Cells ◽  
Cell Line ◽  
Cell Fate ◽  
Neural Development ◽  
Es Cells ◽  
Embryonic Stem ◽  
Normal Karyotype ◽  
Es Cell ◽  
Cell Therapies

Human and non-human primate embryonic stem (ES) cells are invaluable resources for developmental studies, pharmaceutical research and a better understanding of human disease and replacement therapies. In 1998, subsequent to the establishment of the first monkey ES cell line in 1995, the first human ES cell line was developed. Later, three of the National Institute of Health (NIH) lines (BG01, BG02 and BG03) were derived from embryos that would have been discarded because of their poor quality. A major challenge to research in this area is maintaining the unique characteristics and a normal karyotype in the NIH-registered human ES cell lines. A normal karyotype can be maintained under certain culture conditions. In addition, a major goal in stem cell research is to direct ES cells towards a limited cell fate, with research progressing towards the derivation of a variety of cell types. We and others have built on findings in vertebrate (frog, chicken and mouse) neural development and from mouse ES cell research to derive neural stem cells from human ES cells. We have directed these derived human neural stem cells to differentiate into motoneurons using a combination of developmental cues (growth factors) that are spatially and temporally defined. These and other human ES cell derivatives will be used to screen new compounds and develop innovative cell therapies for degenerative diseases.

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