Project description:<p>We sought to characterize cellular heterogeneity in the human cerebral cortex at a molecular level during cortical neurogenesis. We captured single cells and generated sequencing libraries using the C1TM Single-Cell Auto Prep System (Fluidigm), the SMARTer Ultra Low RNA Kit (Clontech), and the Nextera XT DNA Sample Preparation Kit (Illumina). We performed unbiased clustering of the single cells and further examined transcriptional variation among cell groups interpreted as radial glia. Within this population, the major sources of variation related to cell cycle progression and the stem cell niche from which radial glia were captured. We found that outer subventricular zone radial glia (oRG cells) preferentially express genes related to extracellular matrix formation, migration, and stemness, including <i>TNC</i>, <i>PTPRZ1</i>, <i>FAM107A</i>, <i>HOPX</i>, and <i>LIFR</i> and related this transcriptional state to the position, morphology, and cell behaviors previously used to classify the cell type. Our results suggest that oRG cells maintain the subventricular niche through local production of growth factors, potentiation of growth factor signals by extracellular matrix proteins, and activation of self-renewal pathways, thereby contributing to the developmental and evolutionary expansion of the human neocortex.</p> <p>For <b>study version 2</b>, we have updated this data set to include additional primary cells that we infer to represent microglia, endothelial cells, and immature astrocytes, as well as additional cells from the developing neural retina, and from iPS-cell derived cerebral organoids. The genes distinguishing these cell populations may reveal biological processes supporting the diverse functions of these cell types as well as vulnerabilities of specific cell types in human genetic diseases and in viral infections.</p> <p>For <b>study version 3</b>, we have updated the data set to include additional primary cells, including those published in Nowakowski, et al., Science 2017: "Spatiotemporal Gene Expression Trajectories Reveal Developmental Hierarchies of the Human Cortex" (<i>in press</i>)</p>
Project description:The loss-of-function mutations in the chromatin remodeler CHD8, a high-risk factor in autism spectrum disorder (ASD), lead to severe developmental delay, however, the underlying mechanisms remains elusive. Here, we use transcriptome and genomic occupancy reveal that CHD8 regulates chromatin accessibility and activates neurogenesis-related genes for cortical neurogenesis.
Project description:Although neurogenesis in the adult brain recapitulates processes that occur during embryonic development, adult neurogenesis exhibits distinct characteristics from its embryonic counterpart. However, the intrinsic mechanism underlying the differential regulation of neurogenesis between these two stages remains unclear. Herein, we show that the ablation of RNA-binding protein HuR in neural stem cells (NSCs) impairs adult, but not embryonic, neurogenesis. HuR is predominantly expressed in the cytoplasm of embryonic NSCs but translocates into the nucleus of adult NSCs. Transcriptomic analysis of HuR-deficient adult NSCs revealed that nuclear HuR primarily regulates alternative splicing of numerous premRNA transcripts, including focal adhesion kinase (FAK). HuR-deficient adult NSCs generate increased FAK mRNA isoforms with shorter 5’ UTRs, leading to enhanced FAK mRNA translation and hyperactivated FAK signaling, and inhibition of FAK ameliorates defective adult neurogenesis and impaired hippocampus-dependent learning in HuR-deficient mice. Taken together, these findings reveal novel mechanistic insights into the differential regulation of embryonic and adult neurogenesis through developmental cytoplasmic-to-nuclear translocation of HuR in NSCs.
Project description:Non-coding regions compose most of the human genome, yet their functionality is poorly defined. In the developing human neocortex, non-coding regulatory elements tightly regulate expression to direct neural progenitor proliferation and neurogenesis. Here, we define thousands of non-coding elements involved in human neurogenesis by contrasting chromatin accessibility via ATAC-seq from the germinal zone and cortical plate.
Project description:Metabolic dysregulation of neurons is associated with diverse human brain disorders. Metabolic reprogramming occurs during neuronal differentiation, but it is not fully understood which molecules regulate metabolic changes at the early stages of neurogenesis. In this study, we report that miR-124 is a driver of metabolic change at the initiating stage of human neurogenesis. Proteome analysis has shown the oxidative phosphorylation pathway to be the most significantly altered among the differentially expressed proteins (DEPs) in the immature neurons after the knockdown of miR-124. In agreement with these proteomics results, miR-124-depleted neurons display mitochondrial dysfunctions, such as decreased mitochondrial membrane potential and cellular respiration. Moreover, morphological analyses of mitochondria in early differentiated neurons after miR-124 knockdown result in smaller and less mature shapes. Lastly, we show the potential of identified DEPs as novel metabolic regulators in early neuronal development by validating the effects of GSTK1 on cellular respiration. GSTK1, which is upregulated most significantly in miR-124 knockdown neurons, reduces the oxygen consumption rate of neural cells. Collectively, our data highlight the roles of miR-124 in coordinating metabolic maturation at the early stages of neurogenesis and provide insights into potential metabolic regulators associated with human brain disorders characterised by metabolic dysfunctions.