Project description:Intestinal organoids accurately recapitulate epithelial homeostasis in vivo, thereby representing a powerful in vitro system to investigate lineage specification and cellular differentiation. Here, we applied a multi-omics framework on stem cell enriched and -depleted mouse intestinal organoids to obtain a holistic view of the molecular mechanisms that drive differential gene expression during adult intestinal stem cell differentiation. Our data revealed a global rewiring of the transcriptome and proteome between intestinal stem cells and enterocytes, with the majority of dynamic protein expression being transcription-driven. Integrating absolute mRNA and protein copy numbers revealed post-transcriptional regulation of gene expression. Probing the epigenetic landscape identified a large number of cell-type specific regulatory elements, which revealed Hnf4g as a major driver of enterocyte differentiation. In summary, by applying an integrative systems biology approach we uncovered multiple layers of gene expression regulation, which contribute to lineage specification and plasticity of the mouse small intestinal epithelium.
Project description:Microarray was used to delineate the global gene expression profile underlying the specific developmental program of two divergent antigen-specific T helper subsets (Th22 versus Th17) by identifying upregulation or downregulation of key lineage-determining transcription factors, cytokines, chemokines and other genes that govern their functional attributes. To identify factors that might distinguish the Th22 and Th17 developmental programs, comparative global transcriptome analysis between these 2 subsets was performed. Naïve splenic CD4+ T cells from OT-II-transgenic mice were isolated and grown in vitro under T-helper lineage-specific conditions in the presence of cognate antigen (ovalbumin) to identify their distinctive global gene-regulation profiles.
Project description:Although higher-order genome organization is tissue-specific, its functional relevance and mechanistic basis are poorly understood. Here we analyzed the dynamics of chromatin interactions for lineage-specific cytokine loci during T helper (Th) differentiation. The naive-to-effector transition is accompanied by a profound shift from promiscuous to highly selective and functionally enriched genome-wide contacts. Despite the establishment of divergent interactomes and global reprogramming of transcription in Th1 versus Th2 commitment, the overall expression status of the contact genes is surprisingly similar between the two lineages. Importantly, the genomic contacts are retained and strengthened precisely at DNA binding sites of the specific lineage-determining STAT transcription factor. The global aggregation of STAT binding loci from genic and non-genic regions highlights a new role for differentiation-promoting transcription factors in direct specification of higher-order nuclear architecture through interacting with regulatory regions. Such subnuclear environments have implications for efficient functioning of the mature effector lymphocytes. Nineteen arrays total: Eighteen microarrays from individual biological replicates, one microarray from a pool of two biological replicates.
Project description:The integration of cell metabolism with signalling pathways, transcription factor networks and epigenetic mediators is critical in coordinating molecular and cellular events during embryogenesis. Induced pluripotent stem cells (IPSCs) are an established model for embryogenesis, germ layer specification and cell lineage differentiation, advancing the study of human embryonic development and the translation of innovations in drug discovery, disease modelling and cell-based therapies. The metabolic regulation of IPSC pluripotency is mediated by balancing glycolysis and oxidative phosphorylation, but there is a paucity of data regarding the influence of individual metabolite changes during cell lineage differentiation. We used <sup>1</sup>H NMR metabolite fingerprinting and footprinting to monitor metabolite levels as IPSCs are directed in a three-stage protocol through primitive streak/mesendoderm, mesoderm and chondrogenic populations. Metabolite changes were associated with central metabolism, with aerobic glycolysis predominant in IPSC, elevated oxidative phosphorylation during differentiation and fatty acid oxidation and ketone body use in chondrogenic cells. Metabolites were also implicated in the epigenetic regulation of pluripotency, cell signalling and biosynthetic pathways. Our results show that <sup>1</sup>H NMR metabolomics is an effective tool for monitoring metabolite changes during the differentiation of pluripotent cells with implications on optimising media and environmental parameters for the study of embryogenesis and translational applications.
Project description:Alternative splicing is critical for development. However, its role in the specification of the three embryonic germ layers is poorly understood. By performing RNA-Seq on human embryonic stem cells (hESCs) and derived endoderm, cardiac mesoderm, and ectoderm cell lineages, we detect distinct alternative splicing programs associated with each lineage. The most prominent splicing program differences are observed between definitive endoderm and cardiac mesoderm. Integrative multi-omics analyses link each program with lineage-specific RNA binding protein regulators, and further suggest a widespread role for Quaking (QKI) in the specification of cardiac mesoderm. Remarkably, knockout of QKI disrupts the cardiac mesoderm-associated alternative splicing program and formation of myocytes. These changes likely arise in part through reduced expression of BIN1 splice variants linked to cardiac development. Collectively, our results thus uncover alternative splicing programs associated with the three germ lineages and demonstrate an important role for QKI in the formation of cardiac mesoderm.
Project description:Microarray was used to delineate the global gene expression profile underlying the specific developmental program of two divergent antigen-specific T helper subsets (Th22 versus Th17) by identifying upregulation or downregulation of key lineage-determining transcription factors, cytokines, chemokines and other genes that govern their functional attributes.