Project description:We have showed that cancer cells (or tumorigenic cells) resemble neural stem/progenitor cells in regulatory network, tumorigenicity and differentiation potential. We have shown PRMT1 is a protein that is upreguated in and promotes vaious cancers. The expression of its gene is localized to embryonic neural cells during vertebrate embryogenesis. The project is to identify the interaction partners of PRMT1, by which PRMT1 regulates neural stemness in both cancer cells and neural stem cells.
Project description:While the core subunits of Polycomb group (PcG) complexes are well characterized, little is known about the dynamics of these protein complexes during cellular differentiation. We used quantitative interaction proteomics to study PcG proteins in mouse embryonic stem cells (mESCs) and neural progenitor cells (NPCs). We found the stoichiometry of PRC1 and PRC2 to be highly dynamic during neural differentiation.
Project description:Metabolism is vital to cellular function and tissue homeostasis during human lung development. In utero, embryonic pluripotent stem cells undergo endodermal differentiation towards a lung progenitor cell fate that can be mimicked in vitro using induced human pluripotent stem cells (hiPSCs) to study genetic mutations. To identify differences between wild type and surfactant protein B (SFTPB)-deficient cell lines during endoderm specification towards lung, we used an untargeted metabolomics approach to evaluate the developmental changes in metabolites. We found that the metabolites most enriched during the differentiation from pluripotent stem cell to lung progenitor cell, regardless of cell line, were sphingomyelins and phosphatidylcholines, two important lipid classes in fetal lung development. The SFTPB mutation had no metabolic impact on early endodermal lung development. The identified metabolite signatures during lung progenitor cell differentiation may be utilized as biomarkers for normal embryonic lung development.
Project description:<p>During development of the human brain, multiple cell types with diverse regional identities are generated. Here we report a system to generate early human brain forebrain and mid/hindbrain cell types from human embryonic stem cells (hESCs), and infer and experimentally confirm a lineage tree for the generation of these types based on single-cell RNA-Seq analysis. We engineered <i>SOX2<sup>Cit/+</sup></i> and <i>DCX<sup>Cit/Y</sup></i> hESC lines to target progenitors and neurons throughout neural differentiation for single-cell transcriptomic profiling, then identified discrete cell types consisting of both rostral (cortical) and caudal (mid/hindbrain) identities. Direct comparison of the cell types were made to primary tissues using gene expression atlases and fetal human brain single-cell gene expression data, and this established that the cell types resembled early human brain cell types, including preplate cells. From the single-cell transcriptomic data a Bayesian algorithm generated a unified lineage tree, and predicted novel regulatory transcription factors. The lineage tree highlighted a prominent bifurcation between cortical and mid/hindbrain cell types, confirmed by clonal analysis experiments. We demonstrated that cell types from either branch could preferentially be generated by manipulation of the canonical Wnt/beta-catenin pathway. In summary, we present an experimentally validated lineage tree that encompasses multiple brain regions, and our work sheds light on the molecular regulation of region-specific neural lineages during human brain development.</p>
Project description:Knowledge of cell signaling pathways that drive human neural crest differentiation into craniofacial chondrocytes is incomplete, yet essential for using stem cells to regenerate craniomaxillofacial structures. To accelerate translational progress, we developed a differentiation protocol that generated self-organizing craniofacial cartilage organoids from human embryonic stem cell-derived neural crest stem cells. Histological staining of cartilage organoids revealed tissue architecture and staining typical of elastic cartilage. Protein and post-translational modification (PTM) mass spectrometry and snRNASeq data showed that chondrocyte organoids expressed robust levels of cartilage extracellular matrix (ECM) components: many collagens, aggrecan, perlecan, proteoglycans, and elastic fibers. We identified two populations of chondroprogenitor cells, mesenchyme cells and nascent chondrocytes and the growth factors involved in paracrine signaling between them. We show that ECM components secreted by chondrocytes not only create a structurally resilient matrix that defines cartilage, but also play a pivotal autocrine cell signaling role to determine chondrocyte fate.
Project description:CDC14 phosphatases are critical components of the cell cycle machinery that drives exit from mitosis in yeast. However, the two mammalian paralogs, CDC14A and CDC14B, are dispensable for cell cycle progression or exit, and their function remains unclear. By generating a double Cdc14a; Cdc14b-null mouse model, we report here that CDC14 phosphatases control cell differentiation in pluripotent cells and their absence results in deficient development of the neural system. Lack of CDC14 impairs neural differentiation from embryonic stem cells (ESCs) accompanied by deficient induction of genes controlled by bivalent promoters. During ESC differentiation, CDC14 directly dephosphorylates and destabilizes Undifferentiated embryonic Transcription Factor 1 (UTF1), a critical regulator of stemness. In the absence of CDC14, increased UTF1 levels prevent the firing of bivalent promoters, resulting in defective induction of the transcriptional programs required for differentiation. These results suggest that mammalian CDC14 phosphatases function during the terminal exit from the cell cycle by modulating the transition from the pluripotent to the differentiated chromatin state, at least partially by controlling chromatin dynamics and transcription in a UTF1-dependent manner.
Project description:Defining molecular controls that orchestrate human brain development is essential for uncovering the complexity behind neurodevelopment and the pathogenesis of neurological disorders. Due to the difficulties in accessing embryonic and fetal brain tissues, the differentiation of human pluripotent stem cell (hPSC)-derived three-dimensional neural organoids has made it possible to recapitulate this developmental process in vitro and provide a unique opportunity to investigate human brain development and disease. To elucidate the molecular programs that drive this highly dynamic process, here, we generate a comprehensive trans-omic map of the phosphoproteome, proteome, and transcriptome of the initial stages of pluripotency and neural differentiation towards the formation of cerebral organoids. Our integrative analysis uncovers key phospho-signalling events underlying neural lineage differentiation, and their convergence on transcriptional (co-)factors and chromatin remodellers that govern downstream gene regulatory networks (GRNs). Comparative analysis with developing human and mouse embryos using these GRNs demonstrates the fidelity of our early cerebral organoids in modelling embryonic brain development. Finally, we demonstrate biochemical modulation of the AKT signalling as a key molecular switch for controlling human cerebral organoid formation. Our data provides a comprehensive resource to gain insight into the molecular controls in human embryonic brain development and also provide a guide for future development of protocols for human cerebral organoid differentiation.
Project description:Regulation of gene expression underlies the establishment and maintenance of cell identity. Chromatin structure and gene activity are linked. Recently CTCF anchored loops have been described as major features of chromatin organisation. However, the dynamics and role for these structures in differentiation is unknown. We used Tethered Chromatin Conformation Capture (TCC) to assess for the dynamics of CTCF-anchor loop formation upon differentiation of mouse embryonic stem cells (ESC) and neural stem cells (NSC).
Project description:We determined genome-wide nucleosome occupancy in mouse embryonic stem cells and their neural progenitor and embryonic fibroblast counterparts to assess features associated with nucleosome positioning during lineage commitment. Cell type and protein specific binding preferences of transcription factors to sites with either low (e.g. Myc, Klf4, Zfx) or high (e.g. Nanog, Oct4 and Sox2) nucleosome occupancy as well as complex patterns for CTCF were identified. Nucleosome depleted regions around transcription start and termination sites were broad and more pronounced for active genes, with distinct patterns for promoters classified according to their CpG-content or histone methylation marks. Throughout the genome nucleosome occupancy was dependent on the presence of certain histone methylation or acetylation modifications. In addition, the average nucleosome-repeat length increased during differentiation by 5-7 base pairs, with local variations for specific genomic regions. Our results reveal regulatory mechanisms of cell differentiation acting through nucleosome repositioning. We have determined genome-wide nucleosome position maps in mouse embryonic stem cells (ESCs), neural progenitor cells (NPCs) derived from these ESCs by retinoic acid induced differentiation as well as mouse embryonic fibroblasts (MEFs) from the corresponding mouse strain