Project description:The directed differentiation of induced pluripotent stem (iPS) and embryonic stem (ES) cells into definitive endoderm (DE) would allow the derivation of otherwise inaccessible progenitors for endodermal tissues. However, a global comparison of the relative equivalency of DE derived from iPS and ES populations has not been performed. Recent reports of molecular differences between iPS and ES cells have raised uncertainty as to whether iPS cells could generate autologous endodermal lineages in vitro. Here, we have shown that both mouse iPS and parental ES cells exhibited highly similar in vitro capacity to undergo directed differentiation into DE progenitors. With few exceptions, both cell types displayed similar surges in gene expression of specific master transcriptional regulators and global transcriptomes that define the developmental milestones of DE differentiation. Microarray analysis showed considerable overlap between the genetic programs of DE derived from ES/iPS cells in vitro and authentic DE from mouse embryos in vivo. Intriguingly, iPS cells exhibited aberrant silencing of imprinted genes known to participate in endoderm differentiation, yet retained a robust ability to differentiate into DE. Our results show that, despite some molecular differences, iPS cells can be efficiently differentiated into DE precursors, reinforcing their potential for development of cell-based therapies for diseased endodermal-derived tissues. Comparison of mouse ES cells, mouse iPS cells, and E8.25 Mouse embryos; in the undifferentiated state and definitive endoderm differentiated state. ckit+/Sox2dim =definitive endoderm (day 5 of differentiation in vitro); Sox2bright =undifferentiated ES or iPS cells (day 0 of differentiation); ENDM1+/Epcam+/SSlo=foregut endoderm sorted from mouse E8.25 embryos; Epcam+/ENDM1 negative =sorted comparison population from mouse E8.25 embryos.
Project description:Primitive neural stem cells (NSCs) could be derived from pluripotent mouse embryonic stem (ES) cells, and then differentiate into definitive-type neural stem cells which resemble NSCs obtained from the central nervous system. Hence, primitive NSCs define an early stage of neural induction and provide a model to understand the mechanism that controls initial neural commitment. In this study, we performed microarray assay to analyze the global transcriptional profiles in mouse ES cell-derived primitive and definitive NSCs and to depict the molecular changes during the multi-staged neural differentiation process.
Project description:We evaluated the hepatic developmental toxicity of TBBPA/TBBPS/TCBPA with a human embryonic stem cells (hESC) system. We found that TBBPA/TBBPS/TCBPA might adversely affect human hepatocyte-like cells specification from hESCs via mainly impairing definitive endoderm specifications, suggesting the early stages of embryonic development are susceptible to the three compounds.
Project description:Primitive neural stem cells (NSCs) could be derived from pluripotent mouse embryonic stem (ES) cells, and then differentiate into definitive-type neural stem cells which resemble NSCs obtained from the central nervous system. Hence, primitive NSCs define an early stage of neural induction and provide a model to understand the mechanism that controls initial neural commitment. In this study, we performed microarray assay to analyze the global transcriptional profiles in mouse ES cell-derived primitive and definitive NSCs and to depict the molecular changes during the multi-staged neural differentiation process. Primitive NSCs derived directly from ESCs in Lif (p-NSC_L), primitive NSCs that were sub-cultured in the presence of Lif and FGF (p-NSC_LF), as well as definitive NSCs derived from primitive NSCs in medium containing FGF and EGF, were collected for RNA extraction and hybridization on Affymetrix microarrays. Mouse ESCs and NSCs obtained from mouse embryonic brain (E11.5) were included for controls. For each cell type, we collected two biological replicate samples for microarray analysis.
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.
Project description:The directed differentiation of induced pluripotent stem (iPS) and embryonic stem (ES) cells into definitive endoderm (DE) would allow the derivation of otherwise inaccessible progenitors for endodermal tissues. However, a global comparison of the relative equivalency of DE derived from iPS and ES populations has not been performed. Recent reports of molecular differences between iPS and ES cells have raised uncertainty as to whether iPS cells could generate autologous endodermal lineages in vitro. Here, we have shown that both mouse iPS and parental ES cells exhibited highly similar in vitro capacity to undergo directed differentiation into DE progenitors. With few exceptions, both cell types displayed similar surges in gene expression of specific master transcriptional regulators and global transcriptomes that define the developmental milestones of DE differentiation. Microarray analysis showed considerable overlap between the genetic programs of DE derived from ES/iPS cells in vitro and authentic DE from mouse embryos in vivo. Intriguingly, iPS cells exhibited aberrant silencing of imprinted genes known to participate in endoderm differentiation, yet retained a robust ability to differentiate into DE. Our results show that, despite some molecular differences, iPS cells can be efficiently differentiated into DE precursors, reinforcing their potential for development of cell-based therapies for diseased endodermal-derived tissues.
Project description:Foxa2 is required for endoderm differentiation into hepatic lineage. The mechanism of activation for Foxa2 during this developmental process has not been elucidated yet. We established an in vitro system to guide ES cells differentiating into definitive endoderm (DE) cells and the following DE cells to early hepatic cells. ChIP-seq assays have been successfully performed to assess Foxa2 binding profile. Over 50% of Foxa2 target genes in DE cells were found being activated in hepatic cells which were at a stage later than DE stage. Therefore, our finding at genome-wide level proved Foxa2 serving as a pioneer factor at DE stage. Furthermore, Foxa2 could specifically induce H3K4me2 modifications to the promoter/enhancer regions of many hepatic genes to pre-mark the chromatin, and determine the hepatic lineage differentiation competence. Our study illustrated the wide existence of Foxa2M-bM-^@M-^Ys pioneer factor function and uncovered the correlation between pioneer factor and chromatin pre-mark. These findings will be helpful for understanding the developmental process of hepatogenesis and efficiently controlling Foxa2 during hepatic induction for generating functional hepatocytes. Examination of Foxa2 binding sites in mESC-derived DE cells
Project description:During mammalian pre-implantation development, the cells of the blastocyst’s inner cell mass differentiate into the epiblast and primitive endoderm lineages, which give rise to the fetus and extra-embryonic tissues, respectively. Extra-embryonic endoderm differentiation can be modeled in vitro by induced expression of GATA transcription factors in mouse embryonic stem cells. Here we use this GATA-inducible system to quantitatively monitor the dynamics of global proteomic changes during the early stages of this differentiation event and also investigate the fully differentiated phenotype, as represented by embryo-derived extra-embryonic endoderm (XEN) cells. Using mass spectrometry-based quantitative proteomic profiling with multivariate data analysis tools, we reproducibly quantified 2,336 proteins across three biological replicates and have identified clusters of proteins characterized by distinct, dynamic temporal abundance profiles. We first used this approach to highlight novel marker candidates of the pluripotent state and extra-embryonic endoderm differentiation. Through functional annotation enrichment analysis, we have shown that the downregulation of chromatin-modifying enzymes, the re-organization of membrane trafficking machinery and the breakdown of cell-cell adhesion are successive steps of the extra-embryonic differentiation process. Thus, applying a range of sophisticated clustering approaches to a time-resolved proteomic dataset has allowed the elucidation of complex biological processes which characterize stem cell differentiation and could establish a general paradigm for the investigation of these processes.
Project description:Foxa2 is required for endoderm differentiation into the hepatic lineage. The mechanism of activation for Foxa2 during this developmental process has not been elucidated yet. We established an in vitro system to guide ES cells differentiating into definitive endoderm (DE) cells and the following DE cells to early hepatic cells. ChIP-seq assays have been successfully performed to assess the Foxa2 binding profile. Over 50% of Foxa2 target genes in DE cells were found to be activated in hepatic cells which were at a stage later than the DE stage. Therefore, our finding at the genome-wide level proved Foxa2 serves as a pioneer factor at the DE stage. Furthermore, Foxa2 could specifically induce H3K4me2 modifications to the promoter/enhancer regions of many hepatic genes to pre-mark the chromatin, and determine the hepatic lineage differentiation competence. Our study illustrated the wide existence of Foxa2's pioneer factor function and uncovered the correlation between pioneer factor and chromatin pre-mark. These findings will be helpful for understanding the developmental process of hepatogenesis and efficiently controlling Foxa2 during hepatic induction for generating functional hepatocytes. To further gain a genome-wide view of Foxa2's effects on its target gene expression, 3 representative time points from the ES cell differentiation process to hepatic cells were selected for cDNA microarray analysis: 1) Day 0, representing ES cells, where there was no Foxa2 expression; 2) Day 5, representing DE cells; and 3) Day 7, representing early hepatic cells.