Project description:Understanding the molecular mechanisms controlling early cell fate decisions in mammals is a major objective towards the development of robust methods for the differentiation of human pluripotent stem cells into clinically relevant cell types. Here, we used human embryonic stem cells (hESCs) to study specification of definitive endoderm in vitro. Using a combination of whole genome expression and ChIP-seq analyses, we established a hierarchy of transcription factors regulating endoderm specification. Importantly, pluripotency factors, namely NANOG, OCT4 and SOX2 have an essential function in this network by actively directing differentiation. Indeed, these transcription factors control the expression of EOMES, which marks the onset of endoderm specification. In turn, EOMES interacts with SMAD2/3 to initiate the transcriptional network governing endoderm formation. Together, these results provide for the first time a comprehensive molecular model connecting the transition from pluripotency to endoderm specification during mammalian development. ChIP-Seq of Eomesodermin binding in human embyonic stem cells, differentiated towards an endodermal fate for 48h in chemically-defined culture media. Includes an input DNA control. Supplementary file GSE26097_README.txt contains descriptions of the raw data files and processed data files.
Project description:Understanding the molecular mechanisms controlling early cell fate decisions in mammals is a major objective towards the development of robust methods for the differentiation of human pluripotent stem cells into clinically relevant cell types. Here, we used human embryonic stem cells (hESCs) to study specification of definitive endoderm in vitro. Using a combination of whole genome expression and ChIP-seq analyses, we established a hierarchy of transcription factors regulating endoderm specification. Importantly, pluripotency factors, namely NANOG, OCT4 and SOX2 have an essential function in this network by actively directing differentiation. Indeed, these transcription factors control the expression of EOMES, which marks the onset of endoderm specification. In turn, EOMES interacts with SMAD2/3 to initiate the transcriptional network governing endoderm formation. Together, these results provide for the first time a comprehensive molecular model connecting the transition from pluripotency to endoderm specification during mammalian development.
Project description:The Tbx factors Eomesodermin (Eomes) and Brachyury instruct endoderm and mesoderm specification. Both Tbx factors have common large overlap in chromatin binding sites, however their embryonic phenotypes of mutants largely differ. In this study, we delineate the distinct binding patterns and gene target sets of Eomes and Brachyury providing a molecular model of distinct fate specification programs.
Project description:The definitive endoderm germ layer is the provenance of multiple internal organs, including the lungs, liver, pancreas and intestines. Molecular events driving initial endoderm germ layer specification and subsequent anterior-posterior patterning of endoderm into distinct organ primordia remain largely cryptic. Through microarray analyses, we captured genome-wide transcriptional dynamics driving successive stages of endoderm development with the intent of identifying novel regulatory genes or diagnostic markers that respectively drive or mark endoderm committment. HES3 human embryonic stem cells (hESCs) were differentiated into highly homogeneous endodermal progenitor populations, and microarray analyses were conducted of six different populations at different tiers of the endodermal lineage hierarchy: undifferentiated hESCs, anterior primitive streak (day 1 of in vitro differentiation), definitive endoderm (day 3) and anterior foregut, posterior foregut or midgut/hindgut patterned endoderm populations (day 7). Additionally, we compared hESCs differentiated using two alternative endoderm induction protocols, serum-based or AFBLy-based differentiation (both day 3 of differentiation).
Project description:The definitive endoderm germ layer is the provenance of multiple internal organs, including the lungs, liver, pancreas and intestines. Molecular events driving initial endoderm germ layer specification and subsequent anterior-posterior patterning of endoderm into distinct organ primordia remain largely cryptic. Through microarray analyses, we captured genome-wide transcriptional dynamics driving successive stages of endoderm development with the intent of identifying novel regulatory genes or diagnostic markers that respectively drive or mark endoderm committment.
Project description:Differentiation into diverse cell lineages requires orchestration of gene regulatory networks guiding cell fate choices. Genetic factors acting through changes in transcriptional levels can contribute to cardiovascular disease risk by impacting early stages of development and have cell type-specific effects. We set out to characterize lineage trajectory progression of subpopulations and identify potential disease-related genes by examining their expression changes in single cells during early stages of cardiac lineage specification. Using 43,168 single-cell transcriptomes, we developed novel classification and trajectory analysis methods to dissect cellular composition and gene networks across five discrete time points underlying lineage derivation of mesoderm, definitive endoderm, vascular endothelium, cardiac precursors, and definitive cell types that comprise cardiomyocytes and a previously unrecognized cardiac outflow tract population.
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:This experiment was designed to determine the interactome of SMAD2/3 in human pluripotent stem cells (hPSCs). hPSCs were cultured in standard pluripotency-promoting conditions, or induced to differentiate towards the definitive endoderm lineage for 36h. Endogenous SMAD2/3 was immunoprecipitated from nuclear extracts in these two conditions using a specific antibody. Non-immune IgG immunoprecipitations were performed as negative controls. Three biological replicates per conditions were analyzed by quantitative label-free mass spectrometry.
Project description:FGF Signaling is required for hepatic progenitor cell formation from endoderm. The mechanism of this process is poorly understood We used microarrays to identify genes directly regulated by FGF signaling in definitive endoderm that may be involved in hepatic specification.
Project description:N6-methyladenosine (m6A) plays important role in lineage specifications of embryonic stem cells. However, it is still difficult to systematically dissect the specific m6A sites that are essential for early lineage differentiation. Here, we develop an adenine base editor-based strategy to systematically identify functional m6A sites that control lineage decisions of human embryonic stem cells. We design 7999 sgRNAs targeting 6048 m6A sites to screen for m6A sites that act as either boosters or barriers to definitive endoderm specification of human embryonic stem cells. We identify 78 sgRNAs enriched in the non-definitive endoderm cells and 137 sgRNAs enriched in the definitive endoderm cells. We successfully validate two definitive endoderm promoting m6A sites on SOX2 and SDHAF1 as well as a definitive endoderm inhibiting m6A site on ADM. Our study provides a functional screening of m6A sites and paves the way for functional studies of m6A at individual m6A site level.