Project description:Stem cells are a potential key strategy for treating neurodegenerative diseases in which the generation of new neurons is critical. A better understanding of the characteristics and molecular properties of neural stem cells (NSC) and differentiated neurons can help in assessing neuronal maturity and possibly in devising better therapeutic strategies. We have therefore performed an in-depth gene expression profiling study of the C17.2 NSC line and primary neurons (PN) derived from embryonic mouse brains. Microarray analysis revealed a neuron-specific gene expression signature that distinguishes PN from NSCs, with elevated levels of transcripts involved in neuronal functions such as neurite development, axon guidance, in PN. The same comparison revealed decreased levels of multiple cytokine transcripts such as IFN, TNF, TGF, and IL. Among the differentially expressed genes, we found a statistically significant enrichment of genes in the ephrin, neurotrophin, CDK5 and actin pathways which control multiple neuronal-specific functions. Furthermore, genes involved in cell cycle were among the most significantly changed in PN. In order to better understand the role of cell cycle arrest in mediating NSCs differentiation, we blocked the cell cycle of NSCs with Mitomycin C (MMC) and examined cellular morphology and gene expression signatures. Although these MMC-treated NSCs displayed a neuronal morphology and expressed some neuronal differentiation marker genes, their gene expression patterns was very different from primary neurons. We conclude that: 1) Fully differentiated primary neurons display a specific neuronal gene expression signature; 2) cell-cycle block in NSC does not induce the formation of fully differentiated neurons; 3) Cytokines such as IFN, TNF, TGF and IL are part of normal NSC function and/or physiology; 4) Signaling pathways of ephrin, neurotrophin, CDK5 and actin, related to major neuronal features, are dynamically enriched in genes showing changes in expression level. Gene expression profiles in neuronal stem cell, mitomycin-treated neuronal stem cells and primary neuronal cultures were compared to examine cellular morphology and gene expression signatures during neuronal differentiation.

Project description:Stem cells are a potential key strategy for treating neurodegenerative diseases in which the generation of new neurons is critical. A better understanding of the characteristics and molecular properties of neural stem cells (NSC) and differentiated neurons can help in assessing neuronal maturity and possibly in devising better therapeutic strategies. We have therefore performed an in-depth gene expression profiling study of the C17.2 NSC line and primary neurons (PN) derived from embryonic mouse brains. Microarray analysis revealed a neuron-specific gene expression signature that distinguishes PN from NSCs, with elevated levels of transcripts involved in neuronal functions such as neurite development, axon guidance, in PN. The same comparison revealed decreased levels of multiple cytokine transcripts such as IFN, TNF, TGF, and IL. Among the differentially expressed genes, we found a statistically significant enrichment of genes in the ephrin, neurotrophin, CDK5 and actin pathways which control multiple neuronal-specific functions. Furthermore, genes involved in cell cycle were among the most significantly changed in PN. In order to better understand the role of cell cycle arrest in mediating NSCs differentiation, we blocked the cell cycle of NSCs with Mitomycin C (MMC) and examined cellular morphology and gene expression signatures. Although these MMC-treated NSCs displayed a neuronal morphology and expressed some neuronal differentiation marker genes, their gene expression patterns was very different from primary neurons. We conclude that: 1) Fully differentiated primary neurons display a specific neuronal gene expression signature; 2) cell-cycle block in NSC does not induce the formation of fully differentiated neurons; 3) Cytokines such as IFN, TNF, TGF and IL are part of normal NSC function and/or physiology; 4) Signaling pathways of ephrin, neurotrophin, CDK5 and actin, related to major neuronal features, are dynamically enriched in genes showing changes in expression level.

Project description:A cardinal property of neural stem cells (NSCs) is their ability to adopt multiple fates upon differentiation. The epigenome is widely seen as a read-out of cellular potential and a manifestation of this can be seen in embryonic stem cells (ESCs), where promoters of many lineage-specific regulators are marked by a bivalent epigenetic signature comprising trimethylation of both lysine 4 and lysine 27 of histone H3 (H3K4me3 and H3K27me3, respectively). Bivalency has subsequently emerged as a powerful epigenetic indicator of stem cell potential. Here, we have interrogated the epigenome during differentiation of ESC-derived NSCs to immature GABAergic interneurons. We show that developmental transitions are accompanied by loss of bivalency at many promoters in line with their increasing developmental restriction from pluripotent ESC through multipotent NSC to committed GABAergic interneuron. At the NSC stage, the promoters of genes encoding many transcriptional regulators required for differentiation of multiple neuronal subtypes and neural crest appear to be bivalent, consistent with the broad developmental potential of NSCs. Upon differentiation to GABAergic neurons, all non-GABAergic promoters resolve to H3K27me3 monovalency, whereas GABAergic promoters resolve to H3K4me3 monovalency or retain bivalency. Importantly, many of these epigenetic changes occur prior to any corresponding changes in gene expression. Intriguingly, another group of gene promoters gain bivalency as NSCs differentiate toward neurons, the majority of which are associated with functions connected with maturation and establishment and maintenance of connectivity. These data show that bivalency provides a dynamic epigenetic signature of developmental potential in both NSCs and in early neurons. Neural stem cells derived from mouse embryonic stem cells were differentiated into neurons and FACS purified based on RedStar fluorescence driven by the Tau promoter. Chromatin was prepared from NSCs and neurons (n=1), sonicated to roughly 300bp and immunoprecipitated with antibodies against H3K4me3, H3K27me3, total Histone H3 and total IgG, alongside a 5% input sample. K4/K27 and corresponding input samples were analysed by ChIPSeq

Project description:A cardinal property of neural stem cells (NSCs) is their ability to adopt multiple fates upon differentiation. The epigenome is widely seen as a read-out of cellular potential and a manifestation of this can be seen in embryonic stem cells (ESCs), where promoters of many lineage-specific regulators are marked by a bivalent epigenetic signature comprising trimethylation of both lysine 4 and lysine 27 of histone H3 (H3K4me3 and H3K27me3, respectively). Bivalency has subsequently emerged as a powerful epigenetic indicator of stem cell potential. Here, we have interrogated the epigenome during differentiation of ESC-derived NSCs to immature GABAergic interneurons. We show that developmental transitions are accompanied by loss of bivalency at many promoters in line with their increasing developmental restriction from pluripotent ESC through multipotent NSC to committed GABAergic interneuron. At the NSC stage, the promoters of genes encoding many transcriptional regulators required for differentiation of multiple neuronal subtypes and neural crest appear to be bivalent, consistent with the broad developmental potential of NSCs. Upon differentiation to GABAergic neurons, all non-GABAergic promoters resolve to H3K27me3 monovalency, whereas GABAergic promoters resolve to H3K4me3 monovalency or retain bivalency. Importantly, many of these epigenetic changes occur prior to any corresponding changes in gene expression. Intriguingly, another group of gene promoters gain bivalency as NSCs differentiate toward neurons, the majority of which are associated with functions connected with maturation and establishment and maintenance of connectivity. These data show that bivalency provides a dynamic epigenetic signature of developmental potential in both NSCs and in early neurons. Illumina Expresson BeadChip arrays (MouseRef-8v2.0) were used to assess gene expression changes in neural stem cells (n=5; derived from mouse embryonic stem cells) and their differentiated neuronal progeny (n=3; FACS-purified based on Tau-RedStar expression).

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Hypoxia suppresses neuronal functions in primary neuron, speeds cell cycle progression and affection the differentiation potential of neural stem cells

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