Direct reprogramming of human astrocytes into neural stem cells and neurons (MeDIP)
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ABSTRACT:
ORGANISM(S): Homo sapiens
SUBMITTER: Stefania Corti
PROVIDER: E-GEOD-42908 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:It remains controversial whether the routes from differentiated cells to iPSCs are related to the reverse order of normal developmental processes or independent of them. Here, we generated iPSCs from mouse astrocytes by three (Oct3/4, Klf4 and Sox2 (OKS)), two (OK), or four (OKS plus c-Myc) factors. Sox1, a neural stem cell (NSC)-specific transcription factor, is transiently upregulated during reprogramming and Sox1-positive cells become iPSCs. The upregulation of Sox1 is essential for OK-induced reprogramming. Genome-wide analysis revealed that the gene expression profile of Sox1-expressing intermediate-state cells resembles that of NSCs. Furthermore, the intermediate-state cells are able to generate neurospheres, which can differentiate into both neurons and glial cells. Remarkably, during MEF reprogramming, neither Sox1 upregulation nor an increase in neurogenic potential occurs. Thus, astrocytes are reprogrammed through an NSC-like state, suggesting that reprogramming partially follows the retrograde pathway of normal developmental processes. To investigate the gene expression profile of intermediate-state cells during astrocyte reprogramming, we performed genome-wide gene expression analysis in five samples; starting astrocytes, intermediate-state cells expressing Sox1-GFP, NSCs, iPSCs established from astrocytes, and iPSCs established from MEFs (iPS-MEF-Ng-20D-17) that had previously been reported (Okita, K. et al. Nature 448: 313-317 (2007)). Two (NSCs, iPSCs from astrocytes and MEFs) or three (astrocytes, intermediate-state cells) biological replicates were prepared for microarray samples. Total RNA was extracted with an RNeasy kit (Qiagen). cDNA synthesis and transcriptional amplification were performed using 50-100 ng of total RNA with the GeneChip WT PLUS Reagent Kit (Affymetrix). Fragmented and biotin-labeled cDNA targets were hybridized to GeneChip Mouse Gene 1.0 ST arrays (Affymetrix) according to the manufacturerâ??s protocol. Hybridized arrays were scanned using an Affymetrix GeneChip Scanner.
2015-11-06 | E-GEOD-69237 | biostudies-arrayexpress
Project description:Ectopic expression of the reprogramming factors OCT4, SOX2, or NANOG into human astrocytes in specific cytokine/culture conditions activated the neural stem gene program and induced generation of cells expressing neural stem/precursor markers. Here we compare the whole gene expression profile of primary human astrocytes (Astro) with neural stem cells (HNSC) derived from astrocytes reprogramming
2013-12-01 | E-GEOD-36145 | biostudies-arrayexpress
Project description:We have developed an assay to test the neuroprotective properties of compounds using stem cellM-bM-^@M-^Sderived motor neurons and astrocytes, together with activated microglia as a stress paradigm. Hit compounds were discovered and the transcriptional response on activated astrocytes cells was tested. Neural stem cell (NSC)-derived astrocytes (AC) were activated with LPS and IFN-M-NM-3 and treated with hit compound for 4 hr.
2012-11-03 | E-GEOD-37611 | biostudies-arrayexpress
Project description:Ectopic expression of the reprogramming factors OCT4, SOX2, or NANOG into human astrocytes in specific cytokine/culture conditions activated the neural stem gene program and induced generation of cells expressing neural stem/precursor markers (ASTRO-NSC). To evaluate the epigenetic changes associated with this reprogramming, we analyzed the DNA methylation patterns of Astro-NSC relative to untransfected astrocytes.
2013-01-05 | GSE42908 | GEO
Project description:In this study, we confirmed that transformed dedifferentiated astrocytes and neurons acquired a stem/progenitor cell state, although they still retained gene expression memory from their parental cell-type. Transcriptional network analysis on transformed cells revealed up-regulation of genes involved in three signaling pathways: Wnt signaling, cell cycle and focal adhesion with the gene Spp1, also known as osteopontin (OPN) serving as a key node connecting these three pathways. Inhibition of OPN blocked the formation of aggregated neurospheres, affected the proliferative capacity of transformed cell-types and reduced the expression levels of neural stem cell markers. Specific inhibition of OPN in murine glioma tumors prolonged mice survival. We conclude that OPN is an important player in dedifferentiation of cells during tumor formation, hence its inhibition can be a therapeutic target for glioblastoma. Cortical neurons and astrocytes were derived from 11 days old SynapsinI-Cre and GFAP-Cre mice, respectively. The cells were cultured in their respective media to maintain their identity. These cells were then transduced with HRas-shp53 lentivirus with a transduction efficiency of >90%. The transduced neurons and astrocytes were later switched to neural stem cell media devoid of serum and supplemented with FGF-2 (NSC media). Within one week, these cells became proliferative and aggregated to form free-floating neurospheres. These cells, hereinafter referred to as NSynR53 and AGR53, respectively, were later harvested and mRNA collected for sequencing library generation using DP-seq. To assess the regression of these cells to an undifferentiated state along the differentiation axis, enriched populations of mESC and NSC were also grown in vitro and mRNA obtained from these cells were subjected to sequencing library preparation.
2015-05-11 | E-GEOD-64411 | biostudies-arrayexpress
Project description:Direct cell reprogramming has enabled the direct conversion of skin fibroblasts into functional neurons and oligodendrocytes using a minimal set of cell lineage-specific transcription factors. This approach has substantial advantages since it is rapid and simple, generating the cell type of interest in a single step. However, it remains unknown whether this technology can be applied for directly reprogramming skin cells into astrocytes, the third neural lineage. Astrocytes play crucial roles in neuronal homeostasis and their dysfunctions contribute to the origin and progression of multiple human diseases. Herein, we carried out a screening using several transcription factors involved in defining the astroglial cell fate and identified NFIA, NFIB and SOX9 to be sufficient to convert with high efficiency embryonic and post-natal mouse fibroblasts into astrocytes (iAstrocytes). We proved both by gene expression profiling and functional tests that iAstrocytes are comparable to native brain astrocytes. This protocol can be then employed to generate functional iAstrocytes for a wide range of experimental applications. Induced astrocytes (iAstro) were compared to Fibroblasts (Fibro) as negative control and to primary astrocytes (astro) as positive control. Three biological replicates were analyzed for each experimental group.
2015-06-22 | E-GEOD-59018 | biostudies-arrayexpress
Project description:Astrocytes, the most abundant cells in the central nervous system, promote synapse formation and help refine neural connectivity. Although they are allocated to spatially distinct regional domains during development, it is unknown whether region-restricted astrocytes are functionally heterogeneous. Here we show that postnatal spinal cord astrocytes express several region-specific genes, and that ventral astrocyte-encoded Semaphorin3a (Sema3a) is required for proper motor neuron and sensory neuron circuit organization. Loss of astrocyte-encoded Sema3a led to dysregulated α−motor neuron axon initial segment orientation, markedly abnormal synaptic inputs, and selective death of α−but not of adjacent γ−motor neurons. Additionally, a subset of TrkA+ sensory afferents projected to ectopic ventral positions. These findings demonstrate that stable maintenance of a positional cue by developing astrocytes influences multiple aspects of sensorimotor circuit formation. More generally, they suggest that regional astrocyte heterogeneity may help to coordinate postnatal neural circuit refinement. 12 total samples consisting of three biological replicates each of flow sorted postnatal day 7 dorsal spinal cord astrocytes, ventral spinal cord astrocytes, dorsal SC non astrocytes, and ventral SC non astrocytes
2014-05-02 | E-GEOD-55054 | biostudies-arrayexpress
Project description:We report the first RNA profiing of mammalian neural cells grown in vitro. About 50 million reads are generated by RNA-seq from rat astrocytes, neurons and oligodendrocyte precursor cells in primary culture. These data are compared with theose generated from the correponding mouse neural cells that are acutely purified from brains. Cross-species RNA-seq data analysis revealed hundreds of genes that are differentially expressed between cultured and acutely purified cells. Astrocytes have more such genes compared to neurons and oligodendrocyte precursor cells, indicating that signalling pathways are greatly perturbed in cultured astrocytes. mRNA profiles of rat astrocytes, neurons and oligodendrocyte precursor cells cultured in vitro
2015-09-05 | E-GEOD-72739 | biostudies-arrayexpress
Project description:Brain inflammation, a common feature in neurodegenerative diseases, is a complex series of events, which can be detrimental and even lead to neuronal death. Nonetheless, several studies suggest that inflammatory signals are also positively influencing neural cell proliferation, survival, migration and differentiation. Recently, correlative studies suggested that astrocytes are able to dedifferentiate upon injury, and may thereby re-acquire neural stem cells (NSC) potential. However, the mechanism underlying this dedifferentiation process upon injury remains unclear. In this study, we find that during the early response of reactive gliosis, inflammation induces a conversion of mature astrocytes into neural progenitors. A TNF treatment induces the decrease of specific astrocyte markers, such as GFAP or genes related to glycogen metabolism, while a subset of these cells re-express immaturity markers, such as CD44, Musashi-1 and Oct4. Thus, TNF treatment results in the appearance of cells that exhibit a neural progenitor phenotype and are able to proliferate and differentiate into neurons and/or astrocytes. This dedifferentiation process is maintained as long as TNF is present in the culture medium. In addition, we identify a role for Oct4 in this process, since the TNF-induced dedifferentiation can be prevented by inhibiting Oct4 expression. Our results show that activation of the NF-kB pathway through TNF plays an important role in the dedifferentiation of astrocytes via the re-expression of Oct4. These findings indicate that the first step of reactive gliosis is in fact a dedifferentiation process of resident astrocytes mediated by the NF-kB pathway. This dedifferentiation process is maintained as long as TNF is present in the culture medium. In addition, we identify a role for Oct4 in this process, since the TNF-induced dedifferentiation can be prevented by inhibiting Oct4 expression. Our results show that activation of the NF-kB pathway through TNF plays an important role in the dedifferentiation of astrocytes via the re-expression of Oct4. These findings indicate that the first step of reactive gliosis is in fact a dedifferentiation process of resident astrocytes mediated by the NF-kB pathway. Cultures of primary mouse astrocytes were treated with TNF (50 ng/mL) for 24 hours. Cells were collected and immediately homogenized in cooled down RNA NOW reagent (OZYME). Total RNA was extracted according to RNA NOW manufacturer's recommendations with -20°C overnight incubation for small RNA precipitation. Total RNA integrity and purity were assessed using the Agilent 2100 Bioanalyzer and RNA 6000 Nano LabChip kits (Agilent Technologies). Only good-quality RNA (no contamination or degradation, RIN > 9) was used and further processed. Total RNA samples were reverse-transcribed to double-stranded cDNA using specific primers, which reduce the priming of rRNA. cRNA was generated by in vitro transcription and reverse transcribed into a sense single-stranded cDNA. The cDNA was fragmented, labeled, and hybridized onto Affymetrix GeneChip Mouse Gene 1.0 ST Arrays according to the Ambion Whole Transcript Expression kit for Affymetrix GeneChip Whole Transcript Expression Array Protocol (P/N 4425209 Rev.B 05/2009) and GeneChip WT Terminal Labeling and Hybridization User Manual for use with the Ambion Whole Transcript Expression kit (P/N 702808 Rev.6). Microarrays were then washed, stained, and scanned according to the manufacturer's instructions. The samples cover combinations of 7 time points (0H, 6H, 24H, 48H, 72H, 1W, 2W) and two conditions (TNF and control), with multiple replicates per condition and time point.
2015-09-16 | E-GEOD-73022 | biostudies-arrayexpress
Project description:It remains controversial whether the routes from differentiated cells to iPSCs are related to the reverse order of normal developmental processes or independent of them. Here, we generated iPSCs from mouse astrocytes by three (Oct3/4, Klf4 and Sox2 (OKS)), two (OK), or four (OKS plus c-Myc) factors. Sox1, a neural stem cell (NSC)-specific transcription factor, is transiently upregulated during reprogramming and Sox1-positive cells become iPSCs. The upregulation of Sox1 is essential for OK-induced reprogramming. Genome-wide analysis revealed that the gene expression profile of Sox1-expressing intermediate-state cells resembles that of NSCs. Furthermore, the intermediate-state cells are able to generate neurospheres, which can differentiate into both neurons and glial cells. Remarkably, during MEF reprogramming, neither Sox1 upregulation nor an increase in neurogenic potential occurs. Thus, astrocytes are reprogrammed through an NSC-like state, suggesting that reprogramming partially follows the retrograde pathway of normal developmental processes. To investigate the gene expression profile of intermediate-state cells during astrocyte reprogramming, we performed genome-wide gene expression analysis in five samples; starting astrocytes, intermediate-state cells expressing Sox1-GFP, NSCs, iPSCs established from astrocytes, and iPSCs established from MEFs (iPS-MEF-Ng-20D-17) that had previously been reported (Okita, K. et al. Nature 448: 313-317 (2007)).
2015-11-06 | GSE69237 | GEO