A set of Sox2-dependent OSN enhancers mediates the immediate response to neural induction and default neural differentiation of embryonic stem cells
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ABSTRACT: Sox2 is a transcription factor involved in the regulatory network maintaining the pluripotency of embryonic stem cells in culture as well as in early embryos. In addition, Sox2 plays a pivotal role in neural stem cell formation and neurogenesis. How Sox2 can serve both processes has remained elusive. Here we identified a set of Sox2-dependent neural associated enhancers (SONAE) activated immediately following neural induction and required in neural gene activation. SONAE are a distinct subgroup (1898) of 8531 Oct4/Sox2/Nanog (OSN) bound enhancers, characterized by enhanced Sox2 binding and chromatin accessibility. SONAE activation is triggered by neural induction via Retinoic Acid treatment of wild type cells and is antagonized by mesodermal transcription factors repressing Sox2 following mesoderm induction. Neural differentiation is also set off by default in Smad4 ablated cells resistant to mesodermal induction. Our data provide mechanistic insight into the regulation of early neural versus mesodermal induction in ESCs and embryos.
Project description:A set of Sox2-dependent OSN enhancers mediates the immediate response to neural induction and default neural differentiation of embryonic stem cells
Project description:We showed a novel mechanism in which Ash2l directly binds to super-enhancers of several stemness genes to regulate pluripotency and self-renewal in pluripotent stem cells. Ash2l recruits Oct4/Sox2/Nanog (OSN) to form Ash2l/OSN complex at the super-enhancers of Jarid2, Nanog, Sox2, and Oct4, and further drives enhancer activation, upregulation of stemness genes, and maintains the pluripotent circuitry. Ash2l knockdown abrogates the OSN recruitment to all super-enhancers and further hinders the enhancer activation.
Project description:Lineage-specific transcription factors (TFs) operate as master orchestrators of developmental processes by activating select cis-regulatory enhancers and proximal promoters. Direct DNA binding of TFs ultimately drives context-specific recruitment of the basal transcriptional machinery that comprises RNA Polymerase II (RNAPII) and a host of polymerase-associated multiprotein complexes, including the metazoan-specific Integrator complex. Integrator is primarily known to modulate RNAPII processivity and to surveil RNA integrity across coding genes. Here we show an enhancer module of Integrator that directs cell fate specification by promoting epigenetic changes and TF binding at neural enhancers. Depletion of Integrator’s INTS10 upends neural traits and derails cells towards mesenchymal identity. Commissioning of neural enhancers relies on Integrator’s enhancer module, which stabilizes SOX2 binding at chromatin upon exit from pluripotency. We propose Integrator as a functional bridge between enhancers and promoters and a main driver of early development, providing new insight into a growing family of neurodevelopmental syndromes.
Project description:The BAF complex modulates chromatin accessibility. Specific BAF configurations have functional consequences, and subunit switches are essential for cell differentiation. ARID1B and its paralog ARID1A encode for mutually exclusive BAF subunits. De novo ARID1B haploinsufficient mutations cause a neurodevelopmental disorder spectrum, including Coffin-Siris syndrome, which is characterized by neurological and craniofacial features. Here, we reprogrammed ARID1B+/- Coffin-Siris patient-derived skin fibroblasts into iPSCs, and modeled cranial neural crest cell (CNCC) formation. We discovered that ARID1B is active only during the first stage of this process, coinciding with neuroectoderm specification, where it is part of a lineage-specific BAF configuration (ARID1B-BAF), including SMARCA4, and nine additional subunits. ARID1B-BAF acts as a gate-keeper, ensuring exit from pluripotency and lineage commitment, by attenuating NANOG, SOX2 and the thousands of enhancers directly regulated by these two pluripotency factors at the iPSC stage. In iPSCs, these enhancers are maintained active by an ARID1A-containing BAF. At the onset of differentiation, cells transition from ARID1A-BAF to ARID1B-BAF, eliciting attenuation of the NANOG/SOX2 networks, and triggering pluripotency exit. Coffin-Siris patient cells fail to perform the ARID1A/ARID1B switch, and maintain ARID1A-BAF at pluripotency enhancers throughout all stages of CNCC formation. This leads to a persistent and aberrant SOX2 and NANOG activity, which impairs CNCC formation. In fact, despite showing the typical neural crest signature (TFAP2A+, SOX9+), the ARID1B-haploinsufficient CNCCs are also NANOG-positive, in stark contrast with the ARID1B-wt CNCCs, which are NANOG-negative. These findings suggest a connection between ARID1B mutations, neuroectoderm formation, and a pathogenic mechanism for Coffin-Siris syndrome.
Project description:The spinal cord and mesodermal tissues of the trunk such as the vertebral column and skeletal musculature derive from neuro-mesodermal progenitors (NMPs). Sox2, Brachyury (T) and Tbx6 have been correlated with NMP potency and lineage choice, however, their exact role and interaction in these processes have not been revealed yet. Here we present a global analysis of NMPs and their descending lineages performed on purified cells from E8.5 wild-type and mutant embryos. We show that T, cooperatively with WNT signaling, controls the progenitor state and the switch towards the mesodermal fate. Sox2 acts antagonistically and promotes neural development. Tbx6 reinforces the mesodermal fate choice, represses the progenitor state and confers paraxial fate commitment. Our findings refine previous models and establish new concepts of the molecular principles of mammalian trunk development comprising NMP maintenance, lineage choice and mesoderm formation.
Project description:Raw .d files containing LC-DTIMS-CID-MS for the analysis of lipidomic changes during stem cell differentiation into mesodermal and neural cell lineages.
Project description:Neuromesodermal progenitors are located in the caudal lateral epiblast region of embryos and are important for the generation of spinal cord and somite tissue that forms the vertebrate body. In this study we use single cell transcriptomics to define the molecular signature of in vivo and in vitro NMPs and reverse engineer the mechanism that regulates their differentiation towards the neural and mesodermal lineage.
Project description:We have generated RNA-sequencing datasets of the regulome of mouse neural stem and progenitor cells derived from embryonic stem cells, with allele-specific deletions of Sox2 enhancer cluster regions. RNA-seq experiments were conducted to evaluate the regulatory function of Sox2 candidate enhancers in neural stem and progenitor cells.
Project description:We describe a so far uncharacterized, embryonic and self-renewing Neural Plate Border Stem Cell (NBSC) population with the capacity to differentiate into central nervous and neural crest lineages. NBSCs can be obtained by neural transcription factor-mediated reprogramming (BRN2, SOX2, KLF4, and ZIC3) of human adult dermal fibroblasts and peripheral blood cells (induced Neural Plate Border Stem Cells, iNBSCs) or by directed differentiation from human induced pluripotent stem cells (NBSCs). Moreover, human (i)NBSCs share molecular and functional features with primary Neural Plate Border Stem Cells (pNBSCs) isolated from neural folds of E8.5 mouse embryos. Here we provide single cell RNA-sequencing data of neural tissue derived from two E8.5 mouse embryos. After manual isolation and enzymatic separation E8.5 neural tissue was single cell sorted and RNA sequencing was performed following the Smart-seq2 protocol. In sum, cultured pNBSCs and E8.5 neural tube cells share a similar regional identity and expression signature suggesting that pNBSCs might correspond to an endogenous progenitor in this area of the developing brain.
Project description:CHD3 is a component of the NuRD chromatin remodeller. Mutations in CHD3 cause Snijders Blok-Campeau Syndrome, a neurodevelopmental disorder marked by intellectual disability and craniofacial abnormalities. To unveil the role of CHD3 in craniofacial development, we differentiated CHD3-null induced pluripotent stem cells (iPSCs) into cranial neural crest cells (CNCC). We found that CHD3 expression is low in iPSCs and neuroectoderm, but it is upregulated during CNCC specification, where CHD3-containing NuRD opens the chromatin at BMP-responsive enhancers, to allow binding of DLX5 and other factors. CHD3 loss leads to repression of BMP target genes and imbalance between BMP and Wnt signalling, which ultimately results in aberrant mesodermal fate. Consequently, cranial neural crest specification fails, replaced by mesodermal identity, which can be partially rescued by titrating Wnt levels. Our findings highlight a novel role for CHD3 as pivotal regulator of BMP signalling, essential for proper neural crest specification and craniofacial development.