Project description:Brief expression of pluripotency-associated factors such as OCT4, KLF4, SOX2 and c-MYC (OKSM), in combination with differentiation-inducing signals, was reported to trigger transdifferentiation of fibroblasts into alternative cell types. Here, we show that OKSM expression gives rise to both induced pluripotent stem cells (iPSCs) and iNSCs under conditions that were previously shown to induce only NSC transdifferentiation. Fibroblast-derived iNSC colonies silenced retroviral transgenes and reactivated silenced X chromosomes, both hallmarks of pluripotent stem cells. Moreover, lineage tracing via an Oct4-CreER labeling system demonstrated that virtually all iNSC colonies originate from cells transiently expressing Oct4, whereas ablation of Oct4-positive cells prevented iNSC formation. Lastly, use of an alternative transdifferentiation cocktail that lacks OCT4 and was reportedly unable to support induced pluripotency, yielded iPSCs and iNSCs carrying the Oct4-CreER-derived lineage label. Together, these data suggest that iNSC generation using OKSM and related reprogramming factors requires passage through a transient iPSC state. 5 samples were anlyzed in total, 2 induced pluripotent stem cells (iPSCs), 1 neural stem cells (NSCs) and 2 induced NSCs (iNSCs)
Project description:During the reprogramming of mouse embryonic fibroblasts (MEFs) to induced pluripotent stem cells, the activation of pluripotency genes such as Nanog occurs after the mesenchymal to epithelial transition (MET). Here we report that both adult stem cells (neural stem cells- NSCs) and differentiated cells (astrocytes) of the neural lineage can activate Nanog in the absence of cadherin expression during reprogramming. Gene expression analysis revealed that only the Nanog+Ecadherin+ populations expressed stabilization markers and had upregulated several cell cycle genes; and were transgene independent. Inhibition of Dot1L activity, which has previously been shown to increase MET, enhanced both the numbers of Nanog+ and Nanog+E-cadherin+ colonies, suggesting a MET independent pathway for activation of Nanog in NSCs. Expressing Sox2 in MEFs prior to reprogramming does not alter the ratio of Nanog colonies that express E-cadherin obtained. Taken together these results provide a novel pathway for reprogramming taken by cells of the neural lineage. Neural Stem Cells (NSCs) were induced to reprogram by the induction of Oct4, Sox2, c-Myc and Klf4. Reprogramming colonies that expressed either Nanog alone (N+E-) or Nanog and E-cadherin (N+E+) were sorted by flow cytometry and used as input for RNA-sequencing. There are 3 replicates each for the N+E- and N+E+ samples.
Project description:Cellular reprogramming using chemically defined conditions, without genetic manipulation, is a promising approach for generating clinically relevant cell types for regenerative medicine and drug discovery. However, small molecule-driven approaches for inducing lineage-specific stem cells from somatic cells across lineage boundaries have been challenging to develop. Here, we report highly efficient reprogramming of mouse fibroblasts into induced neural stem cell-like cells (ciNSLCs) using a cocktail of nine small molecules (M9). The resulting ciNSLCs closely resemble primary neural stem cells molecularly and functionally. Transcriptome analysis revealed that M9 induces a gradual and specific conversion of fibroblasts towards a neural fate. During reprogramming specific transcription factors such as Elk1 and Gli2 that are downstream of M9-induced signaling pathways bind and activate endogenous master neural genes to specify neural identity. Our study therefore provides an effective chemical approach for generating neural stem cells from mouse fibroblasts, and reveals mechanistic insights into underlying reprogramming process. Genome-wide binding of Elk1 and Gli2 was analyzed by CHIP-seq for tdMEFs from day 0 (ciNSLC), day 4 (D4), day 8 (D8) of M9-induced neural reprogramming, and ciNSLCs and pri-NPC.
Project description:Cellular reprogramming using chemically defined conditions, without genetic manipulation, is a promising approach for generating clinically relevant cell types for regenerative medicine and drug discovery. However, small molecule-driven approaches for inducing lineage-specific stem cells from somatic cells across lineage boundaries have been challenging to develop. Here, we report highly efficient reprogramming of mouse fibroblasts into induced neural stem cell-like cells (ciNSLCs) using a cocktail of nine small molecules (M9). The resulting ciNSLCs closely resemble primary neural stem cells molecularly and functionally. Transcriptome analysis revealed that M9 induces a gradual and specific conversion of fibroblasts towards a neural fate. During reprogramming specific transcription factors such as Elk1 and Gli2 that are downstream of M9-induced signaling pathways bind and activate endogenous master neural genes to specify neural identity. Our study therefore provides an effective chemical approach for generating neural stem cells from mouse fibroblasts, and reveals mechanistic insights into underlying reprogramming process. Genome-wide epigenetic changes of H3K4me1, H3K4me3, H3K27me3, and H3K27ac were analyzed by CHIP-seq for tdMEFs from day 0 (ciNSLC), day 4 (D4), day 8 (D8) of M9-induced neural reprogramming, and ciNSLCs and pri-NPC.
Project description:We describe a so far uncharacterized, embryonic and self-renewing Neural Plate Border Stem Cell (NBSC) population with the capacity to differentiate into central nervous and neural crest lineages. NBSCs can be obtained by neural transcription factor-mediated reprogramming (BRN2, SOX2, KLF4, and ZIC3) of human adult dermal fibroblasts and peripheral blood cells (induced Neural Plate Border Stem Cells, iNBSCs) or by directed differentiation from human induced pluripotent stem cells (NBSCs). Moreover, human (i)NBSCs share molecular and functional features with an endogenous NBSC population isolated from neural folds of E8.5 mouse embryos. Upon differentiation, iNBSCs give rise to either (1) radial glia-type stem cells, dopaminergic and serotonergic neurons, motoneurons, astrocytes, and oligodendrocytes or (2) cells from the neural crest lineage. Here we provide array-based methylation data of iNBSCs reprogrammed from adult dermal fibroblasts (ADF), iPSC-derived NBSCs and adult dermal fibroblasts. The data provided demonstrate robust changes in the methylation landscape after reprogramming of human adult dermal fibroblasts into iNBSCs.
Project description:We describe a so far uncharacterized, embryonic and self-renewing Neural Plate Border Stem Cell (NBSC) population with the capacity to differentiate into central nervous and neural crest lineages. NBSCs can be obtained by neural transcription factor-mediated reprogramming (BRN2, SOX2, KLF4, and ZIC3) of human adult dermal fibroblasts and peripheral blood cells (induced Neural Plate Border Stem Cells, iNBSCs) or by directed differentiation from human induced pluripotent stem cells. Moreover, human (i)NBSCs share molecular and functional features with an endogenous NBSC population isolated from neural folds of E8.5 mouse embryos. Upon differentiation, iNBSCs give rise to either (1) radial glia-type stem cells, dopaminergic and serotonergic neurons, motoneurons, astrocytes, and oligodendrocytes or (2) cells from the neural crest lineage. Here we provide array-based expression data of primary mouse Neural Plate Border Stem Cells (pNBSCs) derived from E8.5 mouse embryos and radial glia-type stem cells and neural crest progenitors derived thereof. The data provided reveal that pNBSCs can be directed into defined neural cell types of the CNS- and neural crest lineage.
Project description:During the reprogramming of mouse embryonic fibroblasts (MEFs) to induced pluripotent stem cells, the activation of pluripotency genes such as Nanog occurs after the mesenchymal to epithelial transition (MET). Here we report that both adult stem cells (neural stem cells- NSCs) and differentiated cells (astrocytes) of the neural lineage can activate Nanog in the absence of cadherin expression during reprogramming. Gene expression analysis revealed that only the Nanog+Ecadherin+ populations expressed stabilization markers and had upregulated several cell cycle genes; and were transgene independent. Inhibition of Dot1L activity, which has previously been shown to increase MET, enhanced both the numbers of Nanog+ and Nanog+E-cadherin+ colonies, suggesting a MET independent pathway for activation of Nanog in NSCs. Expressing Sox2 in MEFs prior to reprogramming does not alter the ratio of Nanog colonies that express E-cadherin obtained. Taken together these results provide a novel pathway for reprogramming taken by cells of the neural lineage.
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.