ABSTRACT: Analysis of early differentiation fates in human ES cells using diverse dosages of BMP and WNT signaling for the initial induction of differentiation
Project description:Analysis of differentiation fates in human ES cells using diverse dosages of BMP and WNT signaling for the initial induction of differentiation
Project description:A simultaneous stimulation of the Activin / FGF, BMP, and WNT pathways is required for promoting most efficient mesoderm induction in human embryonic stem cells, as well as for subsequent differentiation into cardiomyocytes. To reveal the contributions of three of these signaling pathways to mesoderm formation and cardiac induction, comparative differentiation time-courses were recorded, varying the combinations of signaling factors administered to the cells during the first day of differentiation: FGF (F) + BMP (B) + WNT (W) treatment during the first 24 hours, or FGF + BMP, or BMP + WNT, or FGF + WNT
Project description:Melanocytes are pigment-producing cells of neural crest origin responsible for protecting the skin against UV-irradiation. Melanocyte dysfunction leads to pigmentation defects including albinism, vitiligo, and piebaldism and is a key feature of systemic pathologies such as Hermansky-Pudlak (HP) and Chediak-Higashi (CH) Syndromes. Pluripotent stem cell technology offers a novel approach for studying human melanocyte development and disease. Here we report that timed exposure to activators of WNT, BMP and EDN3 signaling triggers the sequential induction of neural crest and melanocyte precursor fates under dual-SMAD inhibition conditions. Using a SOX10::GFP hESC reporter line, we demonstrate that the temporal onset of WNT activation is particularly critical for human neural crest induction. Surprisingly, suppression of BMP signaling does reduce neural crest yield. Subsequent differentiation of hESC-derived melanocyte precursors under defined conditions yields pure populations of pigmented cells matching the molecular and functional properties of adult melanocytes. Melanocytes from patient-specific iPSCs faithfully reproduce the ultrastructural features of the HP- and CH-specific pigmentation defects with minimal variability across lines. Our data define a highly specific requirement for WNT signaling during neural crest induction and enable the generation of pure populations of hiPSC-derived melanocytes for faithful modeling of human pigmentation disorders. Total RNA obtained from a timecourse of Dual SMAD Inhibition (DSi), Neural Crest (NC), and Melanocyte (BE) differentiation of human embryonic stem cells in triplicate.
Project description:Unraveling complex signaling programs animating developmental lineage-decisions is pivotal to differentiate human pluripotent stem cells (hPSC) into pure populations of desired lineages for regenerative medicine. Developmental signals are strikingly temporally dynamic: BMP and Wnt initially specify primitive streak (progenitor to endoderm) yet 24 hours later suppress endoderm and induce mesoderm. At lineage bifurcations we show mutually-exclusive embryonic lineages are segregated through cross-repressive signals: TGFM-NM-2 and BMP/MAPK duel to respectively specify pancreas versus liver from endoderm. Unilateral endodermal differentiation requires blockade of alternative fates at every stage, revealing a universal developmental strategy for efficient differentiation and anterior-posterior patterning of diverse hPSC lines into highly-pure endodermal populations. This culminated in hPSC-derived hepatic progenitors that, for the first time, engraft long-term in genetically-unconditioned mouse livers and secrete human albumin. Finally, thirty transcriptional and chromatin state maps capturing endoderm commitment revealed endodermal enhancers reside in an unanticipated diversity of "pre-enhancer" chromatin states before activation. Endoderm RNA-seq and ChIP-seq data sets
Project description:Cardiovascular diseases are a major cause of life-threatening burden around the world. The heart has a very low regeneration capacity and donor organs for transplantation are scarce. Therefore regeneration of lost myocardium with stem cell-derived cardiomyocytes (CMs) provides an attractive strategy for heart repair. Human pluripotent stem cells (hPSCs) can be efficiently differentiated in vitro into CMs but the molecular mechanisms behind this process are still not fully understood. In particular identification of secreted autocrine and/or paracrine factors that function as important extrinsic signals remained elusive because the mass spectrometry (MS)-based identification of secreted proteins from cell culture supernatants is impeded by high levels of albumin present in common differentiation media. Thus we established an albumin-free cardiomyogenic differentiation medium and performed secretomics at seven different time points during in vitro differentiation. This analysis led to the identification of 4832 proteins with 1802 being significantly altered during differentiation and 431 of these were annotated as secreted according to gene ontology. Bioinformatics revealed enrichment of extrinsic Wnt pathway-related proteins 3 days upon induction of differentiation and of extracellular matrix proteins in the resulting CMs. Numerous extrinsic components of Wnt, Activin A, Nodal, TGFβ, BMP or FGF signaling pathways were quantitatively assessed during differentiation. Notably, the abundance of pathway agonists was generally lower compared to the respective antagonists but their curves of progression over timer were rather similar. We hypothesize that Activin A, Nodal and TGFβ signaling are turned down shortly upon initiation of cardiac differentiation whereas BMP signaling is switched on. Wnt and FGF signaling peaks between d0 and d3 of differentiation and interestingly, Activin A and TGFβ signaling seem to be reactivated at the cardiac progenitor stages and/or in early CMs.
Project description:Human ES cells respond to activation of the BMP and WNT signaling by upregulating target genes. A 4h time-point following signaling factor stimulation was chosen to reveal immediate-early induced genes which are likely to be direct targets.
Project description:Melanocytes are pigment-producing cells of neural crest origin responsible for protecting the skin against UV-irradiation. Melanocyte dysfunction leads to pigmentation defects including albinism, vitiligo, and piebaldism and is a key feature of systemic pathologies such as Hermansky-Pudlak (HP) and Chediak-Higashi (CH) Syndromes. Pluripotent stem cell technology offers a novel approach for studying human melanocyte development and disease. Here we report that timed exposure to activators of WNT, BMP and EDN3 signaling triggers the sequential induction of neural crest and melanocyte precursor fates under dual-SMAD inhibition conditions. Using a SOX10::GFP hESC reporter line, we demonstrate that the temporal onset of WNT activation is particularly critical for human neural crest induction. Surprisingly, suppression of BMP signaling does reduce neural crest yield. Subsequent differentiation of hESC-derived melanocyte precursors under defined conditions yields pure populations of pigmented cells matching the molecular and functional properties of adult melanocytes. Melanocytes from patient-specific iPSCs faithfully reproduce the ultrastructural features of the HP- and CH-specific pigmentation defects with minimal variability across lines. Our data define a highly specific requirement for WNT signaling during neural crest induction and enable the generation of pure populations of hiPSC-derived melanocytes for faithful modeling of human pigmentation disorders. Total RNA obtained from embryonic stem cells (ESCs), ESC-derived melanocyte progenitors, ESC-derived mature melanocytes, primary melanocytes, and disease-specific induced pluripotent stem cell-derived melanocytes.
Project description:Analysis of mobilized peripheral blood CD34+ cells from a healthy volunteer under erythroid differentiation conditions with and without stimulation to the BMP or Wnt signaling pathways. For erythroid differentiation, expanded CD34+ cells were placed in Stemspan SFEM medium supplemented with 2% pen/strep, 20ng/ml SCF, 1U/ml Epo, 5ng/ml IL3, 2uM dexamethasone, and 1uM beta-estradiol. Arrays were performed 2 hours after addition of cytokines. For signaling pathway stimulation, cells were exposed to 0.5uM BIO (a GSK3 inhibitor) for Wnt pathway activation, 25ng/ml rhBMP4 for BMP pathway activation, or vehicle control for 2 hours. Three biological replicates were performed per treatment group. We used microarrays to detail the global program of gene expression changes after Wnt or BMP pathway stimulation in human CD34+ hematopoietic progenitors under erythroid differentiation conditions. To investigate the changes to gene expression in human CD34+ hematopoietic progenitors following stimulation of the Wnt or BMP pathways during the early stages of erythroid differentiation. Three biological replicates were performed per treatment group.
Project description:The cellular microenvironment shapes stem cell identity and differentiation capacity. Mammalian early embryos are exposed to hypoxia in vivo and benefit from hypoxic culture in vitro. Yet, how different components of the hypoxia response impact stem cell transcriptional networks and lineage choices remains unclear. Here we investigated the effect of acute and prolonged hypoxia on stem cell states and differentiation efficiencies of embryonic and extraembryonic cells. We show that prolonged hypoxia enhances differentiation of embryonic stem (ES) cells towards the mesendoderm lineage by transcriptionally priming cells with a primitive streak signature including Wnt3 and T expression. Exposure to hypoxia in ES culture or during formation of gastrulation-mimicking organoids (gastruloids) moderates T expression and enhances structural complexity. Hypoxic gastruloids generated without exogenous Wnt induction can spontaneously elongate and self-organize. Direct gene regulation by Hif1a, combined with DNA demethylation and metabolic rewiring modulate the transcriptional response and phenotypic outcome. Our findings highlight the influence of the microenvironment on stem cell function and provide a rationale supportive of applying physiological conditions in synthetic embryo models.
Project description:Melanocytes are pigment-producing cells of neural crest origin responsible for protecting the skin against UV-irradiation. Melanocyte dysfunction leads to pigmentation defects including albinism, vitiligo, and piebaldism and is a key feature of systemic pathologies such as Hermansky-Pudlak (HP) and Chediak-Higashi (CH) Syndromes. Pluripotent stem cell technology offers a novel approach for studying human melanocyte development and disease. Here we report that timed exposure to activators of WNT, BMP and EDN3 signaling triggers the sequential induction of neural crest and melanocyte precursor fates under dual-SMAD inhibition conditions. Using a SOX10::GFP hESC reporter line, we demonstrate that the temporal onset of WNT activation is particularly critical for human neural crest induction. Surprisingly, suppression of BMP signaling does reduce neural crest yield. Subsequent differentiation of hESC-derived melanocyte precursors under defined conditions yields pure populations of pigmented cells matching the molecular and functional properties of adult melanocytes. Melanocytes from patient-specific iPSCs faithfully reproduce the ultrastructural features of the HP- and CH-specific pigmentation defects with minimal variability across lines. Our data define a highly specific requirement for WNT signaling during neural crest induction and enable the generation of pure populations of hiPSC-derived melanocytes for faithful modeling of human pigmentation disorders.