ABSTRACT: To study gene expression during endodermal organogenesis, we sought to identify genes expressed in restricted domains during organogenesis. For gene expression analysis, six morphologically distinct endodermal domains were dissected at E11.5: the esophageal region; the lung and distal tracheal region; the stomach region; the hepatic region; the dorsal and ventral pancreatic region; and the intestinal region. Through flow cytometric separation using EpCAM expression to distinguish endoderm from surrounding mesenchyme, pure populations of endoderm progenitors from the esophageal, lung, stomach, pancreatic, and intestinal regions were isolated. Expression of Liv2 was used to isolate a pure population of hepatic endoderm progenitors. Keywords: cell type comparison
Project description:To study gene expression during endodermal organogenesis, we sought to identify genes expressed in restricted domains during organogenesis. For gene expression analysis, six morphologically distinct endodermal domains were dissected at E11.5: the esophageal region; the lung and distal tracheal region; the stomach region; the hepatic region; the dorsal and ventral pancreatic region; and the intestinal region. Through flow cytometric separation using EpCAM expression to distinguish endoderm from surrounding mesenchyme, pure populations of endoderm progenitors from the esophageal, lung, stomach, pancreatic, and intestinal regions were isolated. Expression of Liv2 was used to isolate a pure population of hepatic endoderm progenitors. Keywords: cell type comparison Three biological replicates each containing dissected organ domains from 10-12 pooled embryos flow cytometrically sorted to isolate endoderm were amplified using Ambion Illumina TotalPrep RNA Amplification kit and arrayed on Illumina MouseRef8 v2 chips
Project description:The endoderm is classically defined as the innermost layer of three Metazoan germ layers. During organogenesis, the endoderm gives rise to the digestive and respiratory tracts as well as associated organs such as the liver, pancreas, and lung. At present, however, how the endoderm forms the variety of cell types of digestive and respiratory tracts as well as the budding organs is not well understood. In order to investigate the molecular basis and mechanism of organogenesis and to identify the endodermal organ-related marker genes, we carried out microarray analysis using Xenopus cDNA chips. To achieve this goal, we isolated the Xenopus gut endoderm from three different stages of Xenopus organogenesis, and separated each stage of gut endoderm into anterior and posterior region. Competitive hybridization of cDNA between the anterior and posterior endoderm regions, to screen genes that specifically expressed in the major anterior organs, revealed 891 candidates. We then selected 104 clones for in situ hybridization analysis. Here, we report the identification and expression patterns of the 104 Xenopus endodermal genes, which would serve as useful markers for studying endodermal organ development. Keywords: Xenopus, endoderm, microarray, organogenesis
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: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: TGFβ 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.
Project description:Understanding how distinct cell types arise from common multipotent progenitor cells is a major quest in stem cell biology. This knowledge will aid in the targeted differentiation and growth of stem cells, but also in the discovery of the basis of cellular plasticity and of how tissue programming can be controlled. The liver and pancreas share many aspects of their early development, being both specified in the same region of the endoderm, and, possibly, originating from a common progenitor. However, how pancreas versus liver cell fate decision occurs during embryogenesis and the molecular basis of this cellular plasticity are poorly understood. Here, we use RNA-Seq to define the molecular identity of liver and pancreas progenitors directly in mouse embryos and to investigate the mechanisms regulating the emergence of liver or pancreas as alternative fates from the endoderm. Progenitor cell-specific RNA was obtained from mouse Prox1-EGFP-labeled embryonic cells isolated by FACS at distinct developmental stages, before and after the onset of organogenesis. By integrating the temporal and spatial gene expression profiles, we found mutually exclusive signaling signatures in hepatic and pancreatic progenitors. Importantly, we identified the non-canonical Wnt pathway as a potential developmental regulator of the pancreas versus liver fate decision, being expressed in the foregut endoderm, before the cell fate choice is made, and then maintained in pancreas progenitors but absent in hepatic progenitors. Moreover, when assayed in Xenopus embryos, the non-canonical Wnt pathway is able to promote pancreatic fate and repress hepatic fate in the endoderm, suggesting an ancient mechanism for controlling pancreas versus liver fate choice. We expect that this knowledge will be key to formulate reprogramming strategies to convert adult hepatic cells into pancreatic cells as a cell-based therapeutic approach for diabetes. We performed sequencing-based expression profiling (RNA-Seq) of hepatic and pancreatic progenitors in the mouse at two distinct developmental stages.
Project description:Single cell-based studies have revealed tremendous cellular heterogeneity in stem cell and progenitor compartments, suggesting continuous differentiation trajectories with intermixing of cells at various states of lineage commitment and notable degree of plasticity during organogenesis. The hepato-pancreato-biliary organ system relies on a small endoderm progenitor compartment that gives rise to a variety of different adult tissues, including liver, pancreas, gallbladder, and extra-hepatic bile ducts. Experimental manipulation of various developmental signals in the mouse embryo underscored important cellular plasticity in this embryonic territory. This is also reflected in the existence of human genetic syndromes as well as congenital or environmentally-caused human malformations featuring multiorgan phenotypes in liver, pancreas and gallbladder. Nevertheless, the precise lineage hierarchy and succession of events leading to the segregation of an endoderm progenitor compartment into hepatic, biliary, and pancreatic structures are not yet established. Here, we combine computational modelling approaches with genetic lineage tracing to assess the tissue dynamics accompanying the ontogeny of the hepato-pancreato-biliary organ system. We show that a multipotent progenitor domain persists at the border between liver and pancreas, even after pancreatic fate is specified, contributing to the formation of several organ derivatives, including the liver. Moreover, using single-cell RNA sequencing we define a specialized niche that possibly supports such extended cell fate plasticity.
Project description:The future clinical use of embryonic stem cell (ESC)-based hepatocyte replacement therapy depends on the development of an efficient procedure for differentiation of hepatocyes from ESCs. Here we report that a high density of human embryonic stem cell (ESC)-derived fibroblast-like cells (hESdFs) supported the efficient generation of hepatocyte-like cells (HLCs) with functional and mature hepatic phenotypes from primate ESCs and human induced pluripotent stem cells (iPSCs). Molecular and immunocytochemistry analyses revealed that hESdFs caused a rapid loss of pluripotency and induced a sequential endoderm-to-hepatocyte differentiation in the central area of ESC colonies. Knockdown experiments demonstrated that pluripotent stem cells were directed toward endodermal and hepatic lineages by FGF2 and Activin A secreted from hESdFs. Furthermore, we found that the central region of ESC colonies was essential for the hepatic endoderm-specific differentiation, as its removal caused a complete disruption of endodermal differentiation. In conclusion, we describe a novel in vitro differentiation model, and show that hESdF-secreted factors act in concert with regional features of ESC colonies to induce robust hepatic endoderm differentiation in primate pluripotent stem cells. Total RNA were isolated from ORMES6 ESC, differentiated cells at IVDS2 and 3, and cells in the central foci (IVDS2-C) and peripheral (IVDS2-P) area of ESC colonies at IVDS2. Each condition was repeated twice and used ORMES6 ESC as control.
Project description:The future clinical use of embryonic stem cell (ESC)-based hepatocyte replacement therapy depends on the development of an efficient procedure for differentiation of hepatocyes from ESCs. Here we report that a high density of human embryonic stem cell (ESC)-derived fibroblast-like cells (hESdFs) supported the efficient generation of hepatocyte-like cells (HLCs) with functional and mature hepatic phenotypes from primate ESCs and human induced pluripotent stem cells (iPSCs). Molecular and immunocytochemistry analyses revealed that hESdFs caused a rapid loss of pluripotency and induced a sequential endoderm-to-hepatocyte differentiation in the central area of ESC colonies. Knockdown experiments demonstrated that pluripotent stem cells were directed toward endodermal and hepatic lineages by FGF2 and Activin A secreted from hESdFs. Furthermore, we found that the central region of ESC colonies was essential for the hepatic endoderm-specific differentiation, as its removal caused a complete disruption of endodermal differentiation. In conclusion, we describe a novel in vitro differentiation model, and show that hESdF-secreted factors act in concert with regional features of ESC colonies to induce robust hepatic endoderm differentiation in primate pluripotent stem cells.
Project description:Understanding how distinct cell types arise from common multipotent progenitor cells is a major quest in stem cell biology. This knowledge will aid in the targeted differentiation and growth of stem cells, but also in the discovery of the basis of cellular plasticity and of how tissue programming can be controlled. The liver and pancreas share many aspects of their early development, being both specified in the same region of the endoderm, and, possibly, originating from a common progenitor. However, how pancreas versus liver cell fate decision occurs during embryogenesis and the molecular basis of this cellular plasticity are poorly understood. Here, we use RNA-Seq to define the molecular identity of liver and pancreas progenitors directly in mouse embryos and to investigate the mechanisms regulating the emergence of liver or pancreas as alternative fates from the endoderm. Progenitor cell-specific RNA was obtained from mouse Prox1-EGFP-labeled embryonic cells isolated by FACS at distinct developmental stages, before and after the onset of organogenesis. By integrating the temporal and spatial gene expression profiles, we found mutually exclusive signaling signatures in hepatic and pancreatic progenitors. Importantly, we identified the non-canonical Wnt pathway as a potential developmental regulator of the pancreas versus liver fate decision, being expressed in the foregut endoderm, before the cell fate choice is made, and then maintained in pancreas progenitors but absent in hepatic progenitors. Moreover, when assayed in Xenopus embryos, the non-canonical Wnt pathway is able to promote pancreatic fate and repress hepatic fate in the endoderm, suggesting an ancient mechanism for controlling pancreas versus liver fate choice. We expect that this knowledge will be key to formulate reprogramming strategies to convert adult hepatic cells into pancreatic cells as a cell-based therapeutic approach for diabetes.
Project description:Methods for differentiating human pluripotent stem cells to pancreatic and liver lineages in vitro have been limited by the inability to identify and isolate distinct endodermal subpopulations specific to these two organs. Here we report that pancreatic and hepatic progenitors can be isolated using the surface markers CD177/NB1 glycoprotein and inducible T-cell costimulatory ligand CD275/ICOSL, respectively, from seemingly homogeneous definitive endoderm derived from human pluripotent stem cells. Anterior definitive endoderm (ADE) subpopulations identified by CD177 and CD275 show inverse activation of canonical and noncanonical WNT signaling. CD177+ ADE expresses and synthesizes the secreted WNT, NODAL and BMP antagonist CERBERUS1 and is specified toward the pancreatic fate. CD275+ ADE receives canonical Wnt signaling and is specified toward the liver fate. Isolated CD177+ ADE differentiates more homogeneously into pancreatic progenitors and into more functionally mature and glucose-responsive β-like cells in vitro compared with cells from unsorted differentiation cultures.