Project description:The generation of induced pluripotent stem cells (iPSCs) and the direct conversion approach provide an invaluable resource of cells for disease modeling, drug screening, and patient-specific cell-based therapy. However, while iPSCs are stable and resemble ESCs in their transcriptome, methylome and function, the vast majority of the directly converted cells represent an incomplete reprogramming state as evident by their aberrant transcriptome and transgene dependency. This raises the question of whether complete and stable nuclear reprogramming can be achieved only in pluripotent cells. Here we demonstrate the generation of stable and fully functional induced trophoblast stem cells (iTSCs) by transient expression of Gata3, Tfap2c and Eomes. Similarly to iPSCs, iTSCs underwent a complete and stable reprogramming process as assessed by transcriptome and methylome analyses and functional assays such as the formation of hemorrhagic lesion and placenta contribution. Careful examination of the conversion process indicated that the cells did not go through a transient pluripotent state. These results suggest that complete nuclear reprograming can be attained in non-pluripotent cells.
Project description:Here we demonstrate the generation of stable induced trophoblast stem cells (iTSCs) from fibroblasts by the transient expression of Gata3, Eomes and Tfap2c. Transcriptome and methylome analyses and functional assays such as hemorrhagic lesion formation and placenta contribution suggested a high degree of conversion. Careful examination of the reprogramming process indicated that the cells did not go through a transient pluripotent state. Detect and compare different H2A.X deposition patterns in ES cells,MEFs and iTSC and TS cells, with Illumina HiSeq 2000
Project description:Chickarmane2008 - Stem cell lineage - NANOG GATA-6 switch
In this work, a dynamical model of lineage
determination based upon a minimal circuit, as discussed in PMID: 17215298
, which contains the Oct4/Sox2/Nanog core as well its interaction
with a few other key genes is discussed.
This model is described in the article:
A computational model for understanding stem cell, trophectoderm and endoderm lineage determination.
Chickarmane V, Peterson C
PloS one. 2008, 3(10):e3478
Abstract:
BACKGROUND: Recent studies have associated the transcription factors, Oct4, Sox2 and Nanog as parts of a self-regulating network which is responsible for maintaining embryonic stem cell properties: self renewal and pluripotency. In addition, mutual antagonism between two of these and other master regulators have been shown to regulate lineage determination. In particular, an excess of Cdx2 over Oct4 determines the trophectoderm lineage whereas an excess of Gata-6 over Nanog determines differentiation into the endoderm lineage. Also, under/over-expression studies of the master regulator Oct4 have revealed that some self-renewal/pluripotency as well as differentiation genes are expressed in a biphasic manner with respect to the concentration of Oct4. METHODOLOGY/
PRINCIPAL FINDINGS: We construct a dynamical model of a minimalistic network, extracted from ChIP-on-chip and microarray data as well as literature studies. The model is based upon differential equations and makes two plausible assumptions; activation of Gata-6 by Oct4 and repression of Nanog by an Oct4-Gata-6 heterodimer. With these assumptions, the results of simulations successfully describe the biphasic behavior as well as lineage commitment. The model also predicts that reprogramming the network from a differentiated state, in particular the endoderm state, into a stem cell state, is best achieved by over-expressing Nanog, rather than by suppression of differentiation genes such as Gata-6.
CONCLUSIONS: The computational model provides a mechanistic understanding of how different lineages arise from the dynamics of the underlying regulatory network. It provides a framework to explore strategies of reprogramming a cell from a differentiated state to a stem cell state through directed perturbations. Such an approach is highly relevant to regenerative medicine since it allows for a rapid search over the host of possibilities for reprogramming to a stem cell state.
This model is hosted on BioModels Database
and identified
by: MODEL8389825246
.
To cite BioModels Database, please use: BioModels Database: An enhanced, curated and annotated resource
for published quantitative kinetic models
.
To the extent possible under law, all copyright and related or
neighbouring rights to this encoded model have been dedicated to the public
domain worldwide. Please refer to CC0 Public Domain
Dedication
for more information.
Project description:Chickarmane2008 - Stem cell lineage determination
In this work, a dynamical model of lineage
determination based upon a minimal circuit, as discussed in PMID: 17215298
, which contains the Oct4/Sox2/Nanog core as well its interaction
with a few other key genes is discussed.
This model is described in the article:
A computational model for understanding stem cell, trophectoderm and endoderm lineage determination.
Chickarmane V, Peterson C
PloS one. 2008, 3(10):e3478
Abstract:
BACKGROUND: Recent studies have associated the transcription factors, Oct4, Sox2 and Nanog as parts of a self-regulating network which is responsible for maintaining embryonic stem cell properties: self renewal and pluripotency. In addition, mutual antagonism between two of these and other master regulators have been shown to regulate lineage determination. In particular, an excess of Cdx2 over Oct4 determines the trophectoderm lineage whereas an excess of Gata-6 over Nanog determines differentiation into the endoderm lineage. Also, under/over-expression studies of the master regulator Oct4 have revealed that some self-renewal/pluripotency as well as differentiation genes are expressed in a biphasic manner with respect to the concentration of Oct4. METHODOLOGY/
PRINCIPAL FINDINGS: We construct a dynamical model of a minimalistic network, extracted from ChIP-on-chip and microarray data as well as literature studies. The model is based upon differential equations and makes two plausible assumptions; activation of Gata-6 by Oct4 and repression of Nanog by an Oct4-Gata-6 heterodimer. With these assumptions, the results of simulations successfully describe the biphasic behavior as well as lineage commitment. The model also predicts that reprogramming the network from a differentiated state, in particular the endoderm state, into a stem cell state, is best achieved by over-expressing Nanog, rather than by suppression of differentiation genes such as Gata-6.
CONCLUSIONS: The computational model provides a mechanistic understanding of how different lineages arise from the dynamics of the underlying regulatory network. It provides a framework to explore strategies of reprogramming a cell from a differentiated state to a stem cell state through directed perturbations. Such an approach is highly relevant to regenerative medicine since it allows for a rapid search over the host of possibilities for reprogramming to a stem cell state.
This model is hosted on BioModels Database
and identified
by: MODEL8390025091
.
To cite BioModels Database, please use: BioModels Database: An enhanced, curated and annotated resource
for published quantitative kinetic models
.
To the extent possible under law, all copyright and related or
neighbouring rights to this encoded model have been dedicated to the public
domain worldwide. Please refer to CC0 Public Domain
Dedication
for more information.
Project description:Here we demonstrate the generation of stable induced trophoblast stem cells (iTSCs) from fibroblasts by the transient expression of Gata3, Eomes and Tfap2c. Transcriptome and methylome analyses and functional assays such as hemorrhagic lesion formation and placenta contribution suggested a high degree of conversion. Careful examination of the reprogramming process indicated that the cells did not go through a transient pluripotent state.
Project description:Human naive pluripotent stem cells have unrestricted lineage potential. Underpinning this property, naive cells are thought to lack chromatin-based lineage barriers. However, this assumption has not been tested. Here, we define the chromatin-associated proteome, histone post-translational modifications and transcriptome of human naive and primed pluripotent stem cells. Our integrated analysis reveals differences in the relative abundance and activities of distinct chromatin modules. We identify a strong enrichment of Polycomb Repressive Complex 2 (PRC2)-associated H3K27me3 in naive pluripotent stem cell chromatin, and H3K27me3 enrichment at promoters of lineage-determining genes, including trophoblast regulators. PRC2 activity acts as a chromatin barrier restricting the differentiation of naive cells towards the trophoblast lineage, while inhibition of PRC2 promotes trophoblast fate induction and cavity formation in human blastoids. Together, our results establish that human naive pluripotent stem cells are not epigenetically unrestricted, but instead possess chromatin mechanisms that oppose the induction of alternative cell fates.
Project description:Cells of the trophoblast lineage constitute the major part of placental tissues in higher mammals. Recent derivation of human trophoblast stem cells (TSC) from placental cytotrophoblasts (CT) and from blastocyst opens new opportunities for studying development and function of human placenta. Here we report that inhibition of TGF pathway leads to direct and robust conversion of primed human pluripotent stem cells into TSC. The resulting cell lines exhibit self-renewal, are able to differentiate into the main trophoblast lineages, and present RNA and epigenetic profiles that are indistinguishable from the TSC lines derived from placenta or blastocyst. Furthermore, activation of YAP pathway is necessary and sufficient for this conversion.
Project description:Cells of the trophoblast lineage constitute the major part of placental tissues in higher mammals. Recent derivation of human trophoblast stem cells (TSC) from placental cytotrophoblasts (CT) and from blastocyst opens new opportunities for studying development and function of human placenta. Here we report that inhibition of TGF pathway leads to direct and robust conversion of primed human pluripotent stem cells into TSC. The resulting cell lines exhibit self-renewal, are able to differentiate into the main trophoblast lineages, and present RNA and epigenetic profiles that are indistinguishable from the TSC lines derived from placenta or blastocyst. Furthermore, activation of YAP pathway is necessary and sufficient for this conversion.