RNA- and ATAC-seq data from hESCs differentiated with Wnt and Activin with or without CPI-203
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ABSTRACT: We report genome-wide changes in chromatin state and transcriptional output following Wnt-priming and subsequent Activin induced differentiation of human embryonic stem cell and the effects of BET bromodomain inhibition during Wnt-priming. The two signals, Wnt and Activin, although provided sequentially, result in stable mesendoderm differentiation (Yoney et al., 2018).
Project description:Nodal/Activin signaling directs mesendoderm specification in early vertebrate embryogenesis. We have characterized transcriptional profiling of human embryonic stem cells and Activin-treated cells at different timepoints. In this dataset, we include the timecourse gene expression data obtained from hESC differentiation post Activin treatment, examining at day 0, 1, 3 and 5.
Project description:Mesendoderm (ME) differentiation of human embryonic stem cells (hESCs) is directed by various extrinsic signals together with intrinsic epigenetic modifications. However, the dynamics of epigenetic modifications and their regulation to initiate ME differentiation remain elusive. In this study, we report that H3K27me3 is decreased during ME initiation, which is essential for the subsequent differentiation by collaborative effects of Activin and Wnt signaling. Mechanistically, Activin decreases the H3K27me3 level via disruption of the SUZ12-EZH2 interaction and EZH2 degradation mediated by Smad2. Our data suggest a two-step process of ME initiation: firstly H3K27me3-marked epigenetic priming and secondly transcription activation. Our findings unravel a critical role of H3K27me3 priming and a direct interaction between extrinsic signals and epigenetic modifications during ME initiation.
Project description:Nodal/Activin signaling directs mesendoderm specification in early vertebrate embryogenesis. We have characterized transcriptional profiling of human embryonic stem cells and Activin-treated cells at different timepoints. In this dataset, we include the timecourse gene expression data obtained from hESC differentiation post Activin treatment, examining at day 0, 1, 3 and 5. Four biological replicates were used for day 0, three for day 1, three for day 3, and four for day 5. Cells were harvested and used for total RNA preparation using Trizol (Invitrogen). Gene expression was analyzed using GeneChip Human Exon 1.0 ST Array (Affymetrix).
Project description:Activin and Wnt signaling are necessary and sufficient for mesendoderm (ME) differentiation of human embryonic stem cells (hESCs). In this study, we report that during the Activin and Wnt induced ME differentiation, Activin/Smad2 induces decrease of the repressive histone modification H3K27me3 by promoting proteasome-dependent degradation of EZH2. As a result, recruitment of the forkhead protein FOXH1 on open chromatin regions integrates the signals of Activin/Smad2 and Wnt/β-catenin to activate the expression of the ME genes including HAS2 and ALDH3A2. Knockdown of HAS2 and ALDH3A2 greatly attenuates ME differentiation. These findings unveil a pathway from extracellular signals to epigenetic modification-mediated gene activation during ME commitment.
Project description:It has now become clear that the process of fate specification during early embryogenesis is mediated by a handful of key signaling pathways. However, how the temporal and spatial integration of these signals plays out to give rise to self-organization of tissues remains obscure. Here we use artificial human gastruloids and quantitative single-cell analysis to dissect the temporal integration of two key pathways WNT and ACTIVIN that along with BMP control gastrulation and primitive streak patterning in model systems. We showed that ACTIVIN elicits a transient signaling response, as well as a transient induction of differentiation. However, unlike BMP and WNT, ACTIVIN cannot induce stable primitive streak formation and mesodermal patterning. Pre-exposure to WNT switches the response of cells to ACTIVIN whereby it becomes a concentration dependent morphogen. This provides evidence for WNT signaling memory that occurs at the transcriptional level and not as a modifier of ACTIVIN signaling dynamics.
Project description:The combination of Wnt pathway activation by the GSK3 inhibitor and ERK pathway inhibition by the MEK inhibitor, which is known as 2i is a well-established method to maintain mouse embryonic stem cell (mESC) self-renewal. Here we show that Activin A also has the ability to promote naive pluripotency of mESCs when combined with the MEK inhibitor PD0325901. mESCs were efficiently propagated in a medium containing both Activin A and the MEK inhibitor (PD0325901). mESCs cultured in Activin+PD retained a pluripotency state that expresses high levels of naive pluripotency-related transcription factors and is able to differentiate into three germ layers under appropriate conditions. They also showed naive pluripotency features, including the preferential usage of the Oct4 distal enhancer and the self-renewal response to Wnt pathway activation. Our finding provides another way to maintain the naive pluripotency state and reveals a role of Activin/Nodal/TGF-β signaling in stabilizing self-renewal gene regulatory networks in mESCs. To compare the gene expression patterns of naive and primed pluripotency states and their responses to Wnt and ERK1/2 MAPK pathway, we performed genome-wide gene expression analysis of mESCs and EpiLCs, and those treated with Wnt pathway activator alone or Wnt pathway activator combined with ERK1/2 MAPK pathway inhibitior.
Project description:Nodal and Activin are morphogens of the TGFbeta superfamily of signaling molecules that direct differential cell fate decisions in a dose- and distance-dependent manner. During early embryonic development the Nodal/Activin pathway is responsible for the specification of mesoderm, endoderm, node and mesendoderm. In contradiction to this drive towards cellular differentiation, the pathway also plays important roles in the maintenance of self-renewal and pluripotency in embryonic and epiblast stem cells. The molecular basis behind stem cell interpretation of Nodal/Activin signaling gradients and the undertaking of disparate cell fate decisions remains poorly understood. Here, we show that any perturbation of endogenous signaling levels in mouse ES cells leads to their exit from self renewal towards divergent differentiation programs. Increasing Nodal signals above basal levels by direct stimulation with Activin promotes differentiation towards the mesendodermal lineages while repression of signaling with the specific Nodal/Activin receptor inhibitor SB431542 induces trophectodermal differentiation. To address how quantitative Nodal/Activin signals are translated qualitatively into distinct cell fates decisions, we performed chromatin immunoprecipitation of phospho-Smad2 the primary downstream transcriptional factor of the Nodal/Activin pathway followed by massively parallel sequencing and show that phospho-Smad2 binds to and regulates distinct subsets of target genes in a dose-dependent manner. Crucially, Nodal/Activin signaling directly controls the Oct4 master regulator of pluripotency by graded phospho-Smad2 binding in the promoter region. Hence stem cells interpret and carry out differential Nodal/Activin signaling instructions via a corresponding gradient of Smad2 phosphorylation that selectively titrates self-renewal against alternative differentiation programs by direct regulation of distinct target gene subsets and Oct4 expression. Four biological replicates consisting of 4 different passages of E14TG2a ES cells at P20, P21, P23 and P24
Project description:Whole cell extracts from mouse Th17 cells treated with activin A were profiled with extensive fractionation and bottom-up proteomics