Project description:Neurogenesis in the adult hippocampus contributes to information processing critical for cognition, adaptation, learning and memory, and is implicated in numerous neurological disorders. New neurons are continuously produced from neural stem cells via a well-controlled developmental process. The immature neuron stage defined by doublecortin (DCX) expression is the most sensitive to regulation by extrinsic factors. However, little is known about the dynamic biology within this critical interval that drives maturation and confers susceptibility to regulating signals. This study aims to test the hypothesis that DCX-expressing immature neurons in adult mouse hippocampus progress through developmental stages via activity of specific transcriptional networks. Using single-cell RNA-seq combined with a novel integrative bioinformatics approach, we discovered that individual immature neuron can be classified into distinct developmental subgroups based on characteristic gene expression profiles and subgroup-specific markers. Comparisons between immature and more mature subgroups revealed novel pathways involved in neuronal maturation. Genes enriched in more immature cells shared significant overlap with genes implicated in neurodegenerative diseases, while genes positively associated with neuronal maturation were enriched for autism-related gene sets. Our study thus discovers molecular signatures of individual adult-born immature neurons and unveils potential novel targets for therapeutic approaches to treat neurodevelopmental and neurological diseases. mRNA sequencing and expression estimation in 64 individual DCX-dsRed+ cells isolated from transgenic DCX-dsRed mice by FACS sorting
Project description:Redox-mediated posttranslational modifications represent a molecular switch that controls major mechanisms of cell function. Nitric oxide (NO) can mediate redox reactions via S-nitrosylation, representing transfer of an NO group to a critical protein thiol. NO is known to modulate neurogenesis and neuronal survival in various brain regions in disparate neurodegenerative conditions. However, a unifying molecular mechanism linking these phenomena remains unknown. Here we report that S-nitrosylation of myocyte enhancer factor 2 (MEF2) transcription factors acts as a redox switch to inhibit both neurogenesis and neuronal survival. Structure-based analysis reveals that MEF2 dimerization creates a pocket, facilitating S-nitrosylation at an evolutionally conserved cysteine residue in the DNA binding domain. S-Nitrosylation disrupts MEF2-DNA binding and transcriptional activity, leading to impaired neurogenesis and survival in vitro and in vivo. Our data define a novel molecular switch whereby redox-mediated posttranslational modification controls both neurogenesis and neurodegeneration via a single transcriptional signaling cascade. Total RNA obtained from human NSCs transfected with constitutively-active MEF2 (MEF2CA) compared to vector control (ptd-Tomato)
Project description:Neurogenesis in the adult hippocampus contributes to information processing critical for cognition, adaptation, learning and memory, and is implicated in numerous neurological disorders. New neurons are continuously produced from neural stem cells via a well-controlled developmental process. The immature neuron stage defined by doublecortin (DCX) expression is the most sensitive to regulation by extrinsic factors. However, little is known about the dynamic biology within this critical interval that drives maturation and confers susceptibility to regulating signals. This study aims to test the hypothesis that DCX-expressing immature neurons in adult mouse hippocampus progress through developmental stages via activity of specific transcriptional networks. Using single-cell RNA-seq combined with a novel integrative bioinformatics approach, we discovered that individual immature neuron can be classified into distinct developmental subgroups based on characteristic gene expression profiles and subgroup-specific markers. Comparisons between immature and more mature subgroups revealed novel pathways involved in neuronal maturation. Genes enriched in more immature cells shared significant overlap with genes implicated in neurodegenerative diseases, while genes positively associated with neuronal maturation were enriched for autism-related gene sets. Our study thus discovers molecular signatures of individual adult-born immature neurons and unveils potential novel targets for therapeutic approaches to treat neurodevelopmental and neurological diseases.
Project description:The integrative and multi-omics view of changes upon FOXG1 reduction reveals an unprecedented multimodality of FOXG1 functions converging on neuronal maturation, fueling novel therapeutic options based on epigenetic drugs to alleviate, at least in part, neuronal dysfunctions. This RNA-seq dataset is part of tis multimodal invetigation of FOXG1 functions.
Project description:Human neurons engineered from induced pluripotent stem cells (iPSCs) through Neurogenin 2 (Ngn2) overexpression are widely used to study neuronal differentiation mechanisms and to model neurological diseases. However, the differentiation paths and heterogeneity of emerged neurons have not been fully explored. Here we used single-cell transcriptomics to dissect the cell states that emerge during Ngn2 overexpression across a time course from pluripotency to neuron functional maturation. We find a substantial molecular heterogeneity in the neuron types generated, with at least two populations that express genes associated with neurons of the peripheral nervous system. Neuron heterogeneity is observed across multiple iPSC clones and lines from different individuals. We find that neuron fate acquisition is sensitive to Ngn2 expression level and the duration of Ngn2 forced expression. Our data reveals that Ngn2 dosage can regulate neuron fate acquisition, and that Ngn2-iN heterogeneity can confound results that are sensitive to neuron type.
Project description:Redox-mediated posttranslational modifications represent a molecular switch that controls major mechanisms of cell function. Nitric oxide (NO) can mediate redox reactions via S-nitrosylation, representing transfer of an NO group to a critical protein thiol. NO is known to modulate neurogenesis and neuronal survival in various brain regions in disparate neurodegenerative conditions. However, a unifying molecular mechanism linking these phenomena remains unknown. Here we report that S-nitrosylation of myocyte enhancer factor 2 (MEF2) transcription factors acts as a redox switch to inhibit both neurogenesis and neuronal survival. Structure-based analysis reveals that MEF2 dimerization creates a pocket, facilitating S-nitrosylation at an evolutionally conserved cysteine residue in the DNA binding domain. S-Nitrosylation disrupts MEF2-DNA binding and transcriptional activity, leading to impaired neurogenesis and survival in vitro and in vivo. Our data define a novel molecular switch whereby redox-mediated posttranslational modification controls both neurogenesis and neurodegeneration via a single transcriptional signaling cascade.
Project description:Human cerebellar development is precisely orchestrated by molecular regulatory networks. Here, we combined single-cell transcriptomics, spatial transcriptomics and chromatin accessibility states to systematically depict an integrative temporal-spatial landscape of human fetal cerebellar development. The multiomic data reveal molecular networks, providing an informative regulatory map to show how and when cell fates are determined. Spatial transcriptomics illustrated the distinct molecular signatures of the progenitors, Purkinje cells and granule cells located in different regions of the developing cerebellar cortex. We identified RORB as a new marker of developing human Purkinje cells, which was not expressed in mice. In addition, the RL progenitors highly expressed the human-specific gene ARHGAP11B , and ARHGAP11B expression led to cerebellar cortex expansion and folding in mice. We finally mapped the genes and single-nucleotide polymorphisms (SNPs) of diseases related to cerebellar dysfunction onto cell types, indicating the cellular basis and possible pathogenesis mechanisms of neuropsychiatric disorders.
Project description:Hypothalamic tanycytes, radial glial cells that share many features with neuronal progenitors, can generate small numbers of neurons in the postnatal hypothalamus, but the identity of these neurons and the molecular mechanisms that control tanycyte-derived neurogenesis are unknown. We report that tanycyte-specific disruption of the NFI family of transcription factors (Nfia/b/x) stimulates proliferation and tanycyte-derived neurogenesis. Single-cell RNA- and ATAC-Seq analysis reveals that NFI factors repress Shh and Wnt signaling in tanycytes, and small molecule inhibition of these pathways blocks proliferation and tanycyte-derived neurogenesis in Nfia/b/x-deficient mice. We show that Nfia/b/x-deficient tanycytes give rise to multiple mediobasal hypothalamic neuronal subtypes that can mature, integrate into hypothalamic circuitry, and selectively respond to changes in internal states. These findings identify molecular mechanisms controlling tanycyte-derived neurogenesis that can potentially be targeted to selectively remodel hypothalamic neural circuitry controlling homeostatic physiological processes.