Homo sapiens
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA335315 | ENA |
REPOSITORIES: ENA
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Project description:Astrocytes, due to the proximity to neuronal lineage and capability to proliferate, are ideal starting cells to regenerate neurons. Human fetal astrocytes have been successfully converted into neuronal cells by small molecules, which offer a broader range of further applications than transcription factor-mediated neuronal reprogramming. Here we report human adult astrocytes could also be converted into neuronal cells by a different set with fewer small molecules. These induced neuronal cells exhibited typical neuronal morphologies, expressed neuronal markers, and displayed neuronal electrophysiological properties. Genome-wide RNA-sequencing analysis showed the gene expression profile of induced neuronal cells resembled that of human embryonic stem cell-differentiated neurons. When transplanted into postnatal mouse brains, these induced neuronal cells could survive in vivo. Altogether, our study provides a new strategy to directly generate transgene-free neurons from human adult astrocytes by small molecules.
2017-06-12 | GSE84826 | GEO
Project description:Direct reprogramming approaches offer an attractive alternative to stem-cell-derived models, allowing the retention of epigenetic information and age-associated cellular phenotypes, as well as a fast method to reach a target cell type. Several groups have previously generated multiple neuronal subtypes, neural progenitor cells, oligodendrocytes, and other cell types directly from fibroblasts. Other groups have had success at the efficient conversion of embryonic fibroblasts to astrocytes but have not yet achieved similar conversion efficiency for adult human fibroblasts. In order to generate astrocytes for the study of adult-stage disorders, we developed an improved direct conversion strategy employing a combination of small molecules to activate specific pathways that induce trans-differentiation of human adult fibroblasts to astrocytes. We demonstrate that this method produces mature GFAP+/S100β+ cells at high efficiency (40-45%), comparable to previous studies utilizing embryonic fibroblasts. Further, Fibroblast-derived induced Astrocytes (FdiAs) are enriched for markers of astrocyte functionality, including ion-channel buffering, gap-junction communication, and glutamate uptake; and exhibit astrocyte-like calcium signaling and neuroinflammatory phenotypes. RNA-Seq analysis indicates an adult rather than fetal astrocytic gene expression signature, with a greater correlation to temporal lobe astrocytes. Fibroblast-derived induced astrocytes provide a useful tool in studying the adult brain and complement existing in vitro models of induced neurons (iNs), providing an additional platform to study late-stage brain disorders.
2024-07-19 | GSE272279 | GEO
Project description:Direct reprogramming approaches offer an attractive alternative to stem-cell-derived models, allowing the retention of epigenetic information and age-associated cellular phenotypes. To explore such age-related phenotypes, several groups have generated multiple neuronal subtypes, neural progenitor cells, oligodendrocytes, and other cell types directly from fibroblasts. Other groups have had success at the efficient conversion of embryonic fibroblasts to astrocytes but have not yet achieved similar conversion efficiency for adult human fibroblasts. In order to generate astrocytes for the study of age-related diseases, we developed an improved direct conversion strategy employing a combination of small molecules to activate specific pathways that induce trans-differentiation of human adult fibroblasts to astrocytes. We demonstrate that this method produces mature GFAP+/S100β+ cells at high efficiency (40-45%), comparable to previous studies utilizing embryonic fibroblasts. Further, Fibroblast-derived induced Astrocytes (FdiAs) are enriched for markers of astrocyte functionality, including ion-channel buffering, gap-junction communication, and glutamate uptake; and exhibit astrocyte-like calcium signaling and neuroinflammatory phenotypes. RNA-Seq analysis indicates an adult rather than fetal astrocytic gene expression signature, with a greater correlation to temporal lobe astrocytes. Fibroblast-derived induced astrocytes provide a useful tool in understanding age-associated disease processes and complement existing in vitro models of induced neurons (iNs), providing an additional platform to study late-stage brain disorders.
2024-08-31 | GSE239320 | GEO
Project description:Small molecules increase direct neural conversion of human fibroblasts
| PRJNA327348 | ENA
Project description:The epigenetic mechanisms that enable specialized astrocytes to retain neurogenic competence throughout adult life are still poorly understood. Here we show that astrocytes that serve as neural stem cells (NSCs) in the adult mouse subventricular zone (SVZ) express the histone methyltransferase EZH2. This Polycomb repressive factor is required for neurogenesis independent of its role in SVZ NSC proliferation, as Ink4a/Arf-deficiency in Ezh2-deleted SVZ NSCs rescues cell proliferation, but neurogenesis remains defective. Olig2 is a direct target of EZH2, and repression of this bHLH transcription factor is critical for neuronal differentiation. Furthermore, Ezh2 prevents the inappropriate activation of genes that specify non-SVZ neuronal subtypes. In the human brain, SVZ cells including local astroglia also express EZH2, correlating with postnatal neurogenesis. Thus, EZH2 is an epigenetic regulator that distinguishes neurogenic SVZ astrocytes, orchestrating distinct and separable aspects of adult stem cell biology, which has important implications for regenerative medicine and oncogenesis. Examination of histone modifications (H3K27me3 and H3K4me3) in subventricular zone neural stem cells
2014-05-02 | E-GEOD-56394 | biostudies-arrayexpress
Project description:Small molecules enable highly efficient neuronal conversion of human fibroblasts
| PRJNA153057 | ENA
Project description:Human astrocytes have reported to reprogram into neurons, but they have yet to be induced to three-dimensional (3D) neural tissue for neural organogenesis. Here, we demonstrate a remarkable strategy for 3D organoid generation by direct reprogramming human astrocytes. By combining overexpression OCT4, suppression p53 and small molecules CHIR99021, SB431542, RepSox and Y27632, termed as Op53-CSBRY, we successfully reprogramed human astrocytes into neural ectodermal cells and further induced human 3D-brain organoid. Those organoids can be finally induced into spinal cord organoids by activating FGF, SHH and BMP signaling. The grafts of Human astrocyte derived spinal cord organoids (hADSC-Organs) can survived, differentiated into spinal cord neurons, migrated long distance, formed synaptic connectivity with host neurons, bridged complete injury spinal cord tissue in mice. This method indicates that human astrocytes could be directly triggered neural organogenesis, and may hold a great promising to support local astrocytes in situ organogenesis after brain damages, such as stroke and spinal cord injury.
2024-02-01 | GSE168635 | GEO
Project description:Stabilization of OCT4 synthetic mRNA in adult human skin cells using small molecules
| PRJNA174050 | ENA
Project description:The epigenetic mechanisms that enable specialized astrocytes to retain neurogenic competence throughout adult life are still poorly understood. Here we show that astrocytes that serve as neural stem cells (NSCs) in the adult mouse subventricular zone (SVZ) express the histone methyltransferase EZH2. This Polycomb repressive factor is required for neurogenesis independent of its role in SVZ NSC proliferation, as Ink4a/Arf-deficiency in Ezh2-deleted SVZ NSCs rescues cell proliferation, but neurogenesis remains defective. Olig2 is a direct target of EZH2, and repression of this bHLH transcription factor is critical for neuronal differentiation. Furthermore, Ezh2 prevents the inappropriate activation of genes that specify non-SVZ neuronal subtypes. In the human brain, SVZ cells including local astroglia also express EZH2, correlating with postnatal neurogenesis. Thus, EZH2 is an epigenetic regulator that distinguishes neurogenic SVZ astrocytes, orchestrating distinct and separable aspects of adult stem cell biology, which has important implications for regenerative medicine and oncogenesis.
2014-05-02 | GSE56394 | GEO
Project description:Effect of small molecules on activated astrocytes
| PRJNA162319 | ENA