Activin A Efficiently Specifies Definitive Endoderm from Human Embryonic Stem Cells Only When Phosphatidylinositol 3‐Kinase Signaling Is Suppressed

  title={Activin A Efficiently Specifies Definitive Endoderm from Human Embryonic Stem Cells Only When Phosphatidylinositol 3‐Kinase Signaling Is Suppressed},
  author={Amanda B McLean and Kevin A. D’Amour and Karen Louise Jones and Malini Krishnamoorthy and Michael Kulik and David M Reynolds and Allan M. Sheppard and Hui-qiong Liu and Ying Xu and Emmanuel E. Baetge and Stephen Dalton},
  journal={STEM CELLS},
Human ESCs (hESCs) respond to signals that determine their pluripotency, proliferation, survival, and differentiation status. In this report, we demonstrate that phosphatidylinositol 3‐kinase (PI3K) antagonizes the ability of hESCs to differentiate in response to transforming growth factor β family members such as Activin A and Nodal. Inhibition of PI3K signaling efficiently promotes differentiation of hESCs into mesendoderm and then definitive endoderm (DE) by allowing them to be specified by… 

The Generation of Definitive Endoderm from Human Embryonic Stem Cells is Initially Independent from Activin A but Requires Canonical Wnt-Signaling

The in vitro differentiation of human ES cells into definitive endoderm is initially independent from the activin A/TGF-beta pathway but requires high canonical Wnt-signaling activity.

Analysis of alternative signaling pathways of endoderm induction of human embryonic stem cells identifies context specific differences

Use of FGF2, W NT3A or PI3K inhibition with high activin A may serve well in definitive endoderm induction followed by WNT3A specific signaling to direct the definitiveendoderm into late endodermal lineages.

Insulin Redirects Differentiation from Cardiogenic Mesoderm and Endoderm to Neuroectoderm in Differentiating Human Embryonic Stem Cells

It is concluded that in hESC/END‐2 cocultures, insulin does not prevent differentiation but favors the neuroectodermal lineage at the expense of mesendodermal lineages.

Mechanistic characterisation of Activin/Smad and PI3K/mTOR crosstalk during the specification of definitive endoderm from human embryonic stem cells

These findings reveal a new and novel connection between the PI3K/mTOR and TGFβ/Activin pathways, which will greatly impact the understanding of both cell fate determination and the preservation of normal cellular functions.

Highly efficient differentiation of hESCs to functional hepatic endoderm requires ActivinA and Wnt3a signaling

The studies provide compelling evidence that Wnt3a signaling is important for coordinated hepatocellular function in vitro and in vivo and demonstrate that WNT3a facilitates clonal plating of hESCs exhibiting functional hepatic differentiation.

Guided Differentiation of Embryonic Stem Cells into Pdx1‐Expressing Regional‐Specific Definitive Endoderm

A detailed chronological analysis revealed that Activin, fibroblast growth factor, or bone morphogenetic protein signals are critical at various steps and that additional short‐range signals are required for differentiation into Pdx1‐expressing cells.



TGFβ/activin/nodal signaling is necessary for the maintenance of pluripotency in human embryonic stem cells

It is shown that in ex vivo mouse blastocyst cultures, SMAD2/3 signaling is also required to maintain the inner cell mass (from which stem cells are derived), demonstrating an interconnection between TGFβ and WNT signaling in these contexts.

Activin A Maintains Pluripotency of Human Embryonic Stem Cells in the Absence of Feeder Layers

It is shown that activin A is secreted by mouse embryonic feeder layers (mEFs) and that culture medium enriched with activin B is capable of maintaining hESCs in the undifferentiated state for >20 passages without the need for feeder layer, conditioned medium from mEFs, or STAT3 activation.

Formation of the definitive endoderm in mouse is a Smad2-dependent process.

These experiments provide the first evidence that TGFbeta signaling pathways are required for specification of the definitive endoderm lineage in mammals and identify Smad2 as a key mediator that directs epiblast derivatives towards an endodermal as opposed to a mesodermal fate.

Characterization of mesendoderm: a diverging point of the definitive endoderm and mesoderm in embryonic stem cell differentiation culture

The results show that mesendoderm is represented as a Gsc-GFP+E-cadherin(ECD)+PDGFRα(αR)+ population and is selectively induced from ES cells under defined conditions containing either activin or nodal, and that the defined culture condition and surface markers developed in this study are applicable for obtaining pure mesendodermal cells and their immediate progenies from genetically unmanipulated ES cells.

Efficient differentiation of human embryonic stem cells to definitive endoderm

The process of definitive endoderm formation in differentiating hES cell cultures includes an apparent epithelial-to-mesenchymal transition and a dynamic gene expression profile that are reminiscent of vertebrate gastrulation that may facilitate the use of hES cells for therapeutic purposes and as in vitro models of development.

Expression of Nodal, Lefty-A, and Lefty-B in Undifferentiated Human Embryonic Stem Cells Requires Activation of Smad2/3*

  • D. Besser
  • Biology
    Journal of Biological Chemistry
  • 2004
Smad2/3 is activated in undifferentiated hESCs and required for the expression of genes controlling Nodal signaling, and there appears to be cross-talk between inhibition of GSK3, a hallmark of Wnt signaling and the Activin/Nodal pathway.

Activation of Akt signaling is sufficient to maintain pluripotency in mouse and primate embryonic stem cells

It is shown that myristoylated, active form of Akt (myr-Akt) maintained the undifferentiated phenotypes in mouse ES cells without the addition of leukemia inhibitory factor (LIF) and support the notion that PI3K/Akt signaling axis regulates ‘stemness’ in a broad spectrum of stem cell systems.

Regulation of Embryonic Stem Cell Self-renewal by Phosphoinositide 3-Kinase-dependent Signaling*

A previously undescribed role for phosphoinositide 3-kinases (PI3Ks) is demonstrated in regulation of murine ES cell self-renewal and inhibition of MAP-Erk kinases reverses the effects of PI3K inhibition on self-Renewal in a time- and dose-dependent manner, suggesting that the elevated ERK activity observed upon PI3k inhibition contributes to the functional response.

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

The PI3K pathway utilizes multiple downstream effectors including mTOR (mammalian target of rapamycin), which is shown to be essential for proliferation in mouse ES cells and early embryos.

Induction and monitoring of definitive and visceral endoderm differentiation of mouse ES cells

This study distinguished definitive and visceral endoderm by using a mouse ES cell line that bears the gfp and human IL2Rα marker genes in the goosecoid (Gsc) and Sox17 loci, and identified seven surface molecules that are expressed differentially in the two populations.