Project description:Glial cells distribute extensively in the brain and execute important functions. However, their developmental process and molecular features are still not fully explored in human, especially for fetal astrocytes. It is known that EGFR is involved in glial development and we found that the emergence of EGFR+ cells are near the start of gliogenesis and majority of those co-expressed SOX2 during human cerebral cortex development at midgestation. We performed single-cell RNA sequencing of thousands of EGFR+ cells in the human fetal brain cortex from GW21 to GW26. Compared with other published brain sequencing data, our dataset highly enriched the progenitor cells and glial cells. Multiple molecularly specific populations were identified.
Project description:Glial progenitor cells comprise the most abundant population of progenitor cells in the adult human brain. They are responsible for CNS remyelination, and likely contribute to the astrogliotic response to brain injury and degeneration as well. Adult human GPCs are biased to differentiate as oligodendrocytes and elaborate new myelin, and yet they retain multilineage plasticity, and can give rise to neurons as well as astrocytes and oligodendrocytes once removed from the adult parenchymal environment. GPCs retain strong mechanisms for cell-autonomous self-renewal, and yet both their phenotype and fate may be dictated by their microenvironment. Using the transcriptional profiles of acutely isolated GPCs, we have begun to understand the operative ligand-receptor interactions involved in these processes, and have identified several key signaling pathways by which adult human GPCs may be reliably instructed to either oligodendrocytic or astrocytic fate. In addition, we have noted significant differences between the expressed genes and dominant signaling pathways of fetal and adult human GPCs, as well as between rodent and human GPCs. The latter data in particular call into question therapeutic strategies predicated solely upon data obtained using rodents, while perhaps highlighting the extent to which evolution has been attended by the phylogenetic modification of glial phenotype and function. Human adult brain dissociates were sorted for one of three markers, either GLT1 (astrocyte, n =3), CD11b (microglia, n=4) or A2B5 (glial progenitor cell, n=7). In addition to positively selected, the negative fraction and unsorted dissociates were collected as matched controls for each sort.
Project description:Young human glial progenitor cells outcompete and replace older and diseased human cells when transplanted into adult human glial chimeric mice
Project description:Glial progenitor cells (GPCs) pervade the human brain. These cells express gangliosides recognized by MAb A2B5, and some but not all can generate oligodendrocytes. Since some A2B5+ GPCs express PDGFa receptor (PDGFRa), which is critical to oligodendrocyte development, we asked if PDGFRa-directed sorting might isolate oligodendrocyte-competent progenitors. We used FACS to sort PDGFRa+ cells from the second trimester fetal human forebrain, based on expression of the PDGFRa epitope CD140a. CD140a+ cells could be maintained as mitotic progenitors that could be instructed to either oligodendrocyte or astrocyte phenotype. Transplanted CD140a+ cells robustly myelinated the hypomyelinated shiverer mouse brain. Microarray confirmed that CD140a+ cells differentially expressed PDGFRA, NG2, OLIG1/2, NKX2.2 and SOX2. Some expressed CD9, thereby defining a CD140a+/CD9+ fraction of oligodendrocyte-biased progenitors. CD140a+ cells differentially expressed genes of the PTN-PTPRZ1, wnt, notch and BMP pathways, suggesting the interaction of self-renewal and fate-restricting pathways in these cells, while identifying targets for their mobilization and instruction. 10 samples, 5 CD140a+, and 5 CD140a- sorted samples for individual fetal human brain
Project description:Human glial progenitor cells (hGPCs) are highly migratory, and glial replacement has the potential to treat those neurological disorders in which astrocytic and oligodendrocytic pathology are contributory. Yet it remains unknown whether allografted human glia can out compete diseased cells to achieve therapeutic replacement in the adult human brain.To that end, we engrafted healthy wild-type (WT) hGPCs into the striata of adult mice that had been earlier chimerized neonatally with mutant HTT-expressing hGPCs generated from Huntington disease (HD)-derived human embryonic stemcells. The WT hGPCs effectively out competed and ultimately eliminated their HD counterparts, repopulating the host striata with healthy humanglia. Single-cell transcriptomics revealed that WT hGPCs actively assumed a dominant competitor phenotype upon interaction with their resident HD counter parts.The outcomes of clonal competition depended primarily upon the age difference between competing clones, in that adult-transplanted WT GPCs effectively out competed their isogenic WT counter parts that had been transplanted neonatally, and which were thus necessarily older.These data suggest that both aged and diseased human glia may be broadly replaced in the adult brain by younger and healthier human glial progenitor cells.
Project description:Glial progenitor cells comprise the most abundant population of progenitor cells in the adult human brain. They are responsible for CNS remyelination, and likely contribute to the astrogliotic response to brain injury and degeneration as well. Adult human GPCs are biased to differentiate as oligodendrocytes and elaborate new myelin, and yet they retain multilineage plasticity, and can give rise to neurons as well as astrocytes and oligodendrocytes once removed from the adult parenchymal environment. GPCs retain strong mechanisms for cell-autonomous self-renewal, and yet both their phenotype and fate may be dictated by their microenvironment. Using the transcriptional profiles of acutely isolated GPCs, we have begun to understand the operative ligand-receptor interactions involved in these processes, and have identified several key signaling pathways by which adult human GPCs may be reliably instructed to either oligodendrocytic or astrocytic fate. In addition, we have noted significant differences between the expressed genes and dominant signaling pathways of fetal and adult human GPCs, as well as between rodent and human GPCs. The latter data in particular call into question therapeutic strategies predicated solely upon data obtained using rodents, while perhaps highlighting the extent to which evolution has been attended by the phylogenetic modification of glial phenotype and function.
Project description:The goals of this research are three-fold: (i) One is to identify genetic changes associated with tumorgenesis that interfere with the ability of transformed glial cells to differentiate. This is connected with (ii) our analysis of the regulation of differentiation in normal glial progentor cells, as only by understanding this in normal cells can we understand what is occurring when differentiation fails in transformed versions of the same cells. (iii) The third is to identify the molecular basis for the greater resistance of transformed glial progenitor cells to chemotherapeutic agents as compared with normal glial progenitor cells. Thus, analysis of the populations provided will yield data crucial to two of our central areas of research, as awarded by NINDS in "Oligodendrocytes & precursors: toxicity of chemotherapy" (5R01NS044701), and "Low-level toxicant perturbation of neural cell function" (1R01ES012708). Our ability to work with essentially unlimited numbers of primary progenitor cells and transformed derivatives of these cells offers one of the few systems in which side-by-side comparison of normal and transformed cells at both the biochemical and molecular levels is possible. Using defined cell populations, expression profiles will be compared to reveal changes in cell type specific markers and regulatory factors associated with transformation. In addition, retention of markers despite transformation may enable identification of new markers useful in the diagnosis of glial tumors. Transformation of glial progenitor cells is associated both with loss of the proteins required for normal differentiation and with an inability to normally activate proteins that function in differentiation control. By side-by-side analysis of gene expression in normal and transformed glial progenitor cells, and analysis of the response to inducers of differentiation in each these populations, we will identify candidate regulators critical in the control of normal differentiation. Identification of these regulators will also provide clues as to overcome the blockade of differentiation that occurs in glial cancers (which represent the majority of adult brain tumors). RNA will be isolated from two separate preparations of glial progenitors. Preparation of purified populations has been described in multiple of our previous publications (Mayer, M. et al. (1994) Development 120, 142-153; Mayer-Pröschel, M. et al. (1997) Neuron 19, 773-785; Rao, M. and Mayer-Pröschel, M. (1997) Dev. Biology 188, 48-63). Total RNA from purified cell cultures will be extracted in a two step process. RNA will first be extracted by dounce homogenization in phenol/guanidine isothiocyonate solution (Trizol, Invitrogen, California) followed by isopropanol precipitation. Contaminating traces of DNA and protein will then be removed by silica-based affinity chromatography and Dnase treatment (NucleoSpin RNA Purification system, Clontech, California). Depending on the cell type, 5x105 cells will typically yield 5-15µg of high quality RNA (OD260/280=2.1 at pH7.5). In order to determine purity and molecular weight distribution, samples will be routinely tested on a Agilent Bioanalyzer. cDNA will be generated from total RNA and then be submitted to one round of amplification and labeling using the messageAmp system (Ambion). Probes are then hybridized to the Affymerix Rat 230 (A/B or 2.0) GeneChip expression array. Array data will be processed using the Micro Array Suite 5.0 (MAS, Affymetrix). .Cel files containing normalized, relative expression data for all genes tested will be used for downstream statistical analysis.
Project description:Glial cells are present throughout the entire nervous system and paly a crucial role in regulating physiological and pathological functions, such as infections, acute injuries and chronic neurodegenerative disorders. The glial cells mainly include astrocytes, microglia, and oligodendrocytes in the central nervous system (CNS), and satellite glial cells (SGCs) in the peripheral nervous system (PNS). Although the glial subtypes and functional heterogeneity is relatively well understood in mice by recent studies using single-cell or single-nucleus RNA-sequencing, no evidence yet has elucidate the transcriptomic profiles of glia cells in PNS and CNS. Here, we used high-throughput single-nucleus RNA-sequencing to map the cellular and functional heterogeneity of SGCs in human dorsal root ganglion (DRG), and astrocytes, microglia, and oligodendrocytes in human spinal cord. In addition, we compared the human findings with previous single-nucleus transcriptomic profiles of glial cells from mouse DRG and spinal cord. This work will comprehensively profile glial cells heterogeneity and will provide a powerful resource for probing the cellular basis of human physiological and pathological conditions related to glial cells.
Project description:The goals of this research are three-fold: (i) One is to identify genetic changes associated with tumorgenesis that interfere with the ability of transformed glial cells to differentiate. This is connected with (ii) our analysis of the regulation of differentiation in normal glial progentor cells, as only by understanding this in normal cells can we understand what is occurring when differentiation fails in transformed versions of the same cells. (iii) The third is to identify the molecular basis for the greater resistance of transformed glial progenitor cells to chemotherapeutic agents as compared with normal glial progenitor cells. Thus, analysis of the populations provided will yield data crucial to two of our central areas of research, as awarded by NINDS in "Oligodendrocytes & precursors: toxicity of chemotherapy" (5R01NS044701), and "Low-level toxicant perturbation of neural cell function" (1R01ES012708). Our ability to work with essentially unlimited numbers of primary progenitor cells and transformed derivatives of these cells offers one of the few systems in which side-by-side comparison of normal and transformed cells at both the biochemical and molecular levels is possible. Using defined cell populations, expression profiles will be compared to reveal changes in cell type specific markers and regulatory factors associated with transformation. In addition, retention of markers despite transformation may enable identification of new markers useful in the diagnosis of glial tumors. Transformation of glial progenitor cells is associated both with loss of the proteins required for normal differentiation and with an inability to normally activate proteins that function in differentiation control. By side-by-side analysis of gene expression in normal and transformed glial progenitor cells, and analysis of the response to inducers of differentiation in each these populations, we will identify candidate regulators critical in the control of normal differentiation. Identification of these regulators will also provide clues as to overcome the blockade of differentiation that occurs in glial cancers (which represent the majority of adult brain tumors). RNA will be isolated from two separate preparations of glial progenitors. Preparation of purified populations has been described in multiple of our previous publications (Mayer, M. et al. (1994) Development 120, 142-153; Mayer-Pröschel, M. et al. (1997) Neuron 19, 773-785; Rao, M. and Mayer-Pröschel, M. (1997) Dev. Biology 188, 48-63). Total RNA from purified cell cultures will be extracted in a two step process. RNA will first be extracted by dounce homogenization in phenol/guanidine isothiocyonate solution (Trizol, Invitrogen, California) followed by isopropanol precipitation. Contaminating traces of DNA and protein will then be removed by silica-based affinity chromatography and Dnase treatment (NucleoSpin RNA Purification system, Clontech, California). Depending on the cell type, 5x105 cells will typically yield 5-15µg of high quality RNA (OD260/280=2.1 at pH7.5). In order to determine purity and molecular weight distribution, samples will be routinely tested on a Agilent Bioanalyzer. cDNA will be generated from total RNA and then be submitted to one round of amplification and labeling using the messageAmp system (Ambion). Probes are then hybridized to the Affymerix Rat 230 (A/B or 2.0) GeneChip expression array. Array data will be processed using the Micro Array Suite 5.0 (MAS, Affymetrix). .Cel files containing normalized, relative expression data for all genes tested will be used for downstream statistical analysis. Keywords: other