Project description:Biologists rely on morphology, function, and specific markers to define the differentiation status of cells. Transcript profiling has expanded the repertoire of these markers by providing the snapshot of cellular status that reflects the activity of all genes. However, such data have been used only to assess relative similarities and differences of these cells. Here we show that principal component analysis (PCA) of global gene expression profiles map cells in multidimensional transcript profile space and the positions of differentiating cells progress in a stepwise manner along trajectories starting from undifferentiated embryonic stem (ES) cells located in the apex. We present three cell lineage trajectories, which represent the differentiation of ES cells into the first three lineages in mammalian development: primitive endoderm, trophoblast, and primitive ectoderm/neural ectoderm. The positions of the cells along these trajectories seem to reflect the developmental potency of cells and can be used as a scale for the potential of cells. Indeed, we show that embryonic germ (EG) cells and induced pluripotent (iPS) cells are mapped near the origin of the trajectories, whereas mouse embryo fibroblast (MEF) and fibroblast cell lines are mapped near the far end of the trajectories. We propose that this method can be used as the non-operational semi-quantitative definition of cell differentiation status and developmental potency. Furthermore, the global expression profiles of cell lineages provide a framework for the future study of in vitro and in vivo cell differentiation. Keywords: cell type comparison design,reference design,replicate design,time series design Most of the cells and RNA samples used in this study were described in detail previously (See paper's citation associated with this dataset). To maximize the uniformity of the microarray data, all the samples, including ones analyzed by DNA microarray previously, were hybridized to the same platform (the NIA Mouse 44K Microarray manufactured by Agilent Technologies: AMADID #015087). The intensity of each gene feature per array was extracted from scanned microarray images using Feature Extraction Software V9.5.
Project description:Biologists rely on morphology, function, and specific markers to define the differentiation status of cells. Transcript profiling has expanded the repertoire of these markers by providing the snapshot of cellular status that reflects the activity of all genes. However, such data have been used only to assess relative similarities and differences of these cells. Here we show that principal component analysis (PCA) of global gene expression profiles map cells in multidimensional transcript profile space and the positions of differentiating cells progress in a stepwise manner along trajectories starting from undifferentiated embryonic stem (ES) cells located in the apex. We present three cell lineage trajectories, which represent the differentiation of ES cells into the first three lineages in mammalian development: primitive endoderm, trophoblast, and primitive ectoderm/neural ectoderm. The positions of the cells along these trajectories seem to reflect the developmental potency of cells and can be used as a scale for the potential of cells. Indeed, we show that embryonic germ (EG) cells and induced pluripotent (iPS) cells are mapped near the origin of the trajectories, whereas mouse embryo fibroblast (MEF) and fibroblast cell lines are mapped near the far end of the trajectories. We propose that this method can be used as the non-operational semi-quantitative definition of cell differentiation status and developmental potency. Furthermore, the global expression profiles of cell lineages provide a framework for the future study of in vitro and in vivo cell differentiation. Keywords: cell type comparison design,reference design,replicate design,time series design
Project description:<p>Defining the number, proportion, or lineage of distinct cell types in the developing human brain is an important goal of modern brain research. We produced single cell transcriptomic profiles for 40,000 cells at mid-gestation to define deep expression profiles corresponding to all known major cell types at this developmental period and compare this with bulk tissue profiles. We identified multiple transcription factors (TFs) and co-factors expressed in specific cell types, including multiple new cell-type-specific relationships, providing an unprecedented resource for understanding human neocortical development and evolution. This includes the first single-cell characterization of human subplate neurons and subtypes of developing glutamatergic and GABAergic neurons. We also used these data to deconvolute single cell regulatory networks that connect regulatory elements and transcriptional drivers to single cell gene expression programs in the developing CNS. We characterized major developmental trajectories that tie cell cycle progression with early cell fate decisions during early neurogenesis. Remarkably, we found that differentiation occurs on a transcriptomic continuum, so that differentiating cells not only express the few key TFs that drive cell fates, but express broad, mixed cell-type transcriptomes prior to telophase. Finally, we mapped neuropsychiatric disease genes to specific cell types, implicating dysregulation of specific cell types in ASD, ID, and epilepsy, as the mechanistic underpinnings of several neurodevelopmental disorders. Together these results provide an extensive catalog of cell types in human neocortex and extend our understanding of early cortical development, human brain evolution and the cellular basis of neuropsychiatric disease.</p>
Project description:The gold standard for examining pluripotency of stem cells is to see whether cells can contribute to entire body of animals. Here we show that the increased frequency of Zscan4 activation in mouse ES cells not only enhances, but also maintains their developmental potency in long-term cell culture. As the potency increases, even a whole animal can be produced from a single ES cell injected into 4N blastocyst at unusually high success rate. Although Zscan4-activated cells express genes that are also expressed in 2-cell stage mouse embryos, transiently Zscan4-activated state of ES cells is not associated with the high potency of ES cells. It is thus concluded that ES cells acquire higher potency by going through transient Zscan4 activation state more frequently than the regular state. Taken together, our results indicate that frequent activation of Zscan4 can rejuvenate pluripotent stem cells.
Project description:The gold standard for examining pluripotency of stem cells is to see whether cells can contribute to entire body of animals. Here we show that the increased frequency of Zscan4 activation in mouse ES cells not only enhances, but also maintains their developmental potency in long-term cell culture. As the potency increases, even a whole animal can be produced from a single ES cell injected into 4N blastocyst at unusually high success rate. Although Zscan4-activated cells express genes that are also expressed in 2-cell stage mouse embryos, transiently Zscan4-activated state of ES cells is not associated with the high potency of ES cells. It is thus concluded that ES cells acquire higher potency by going through transient Zscan4 activation state more frequently than the regular state. Taken together, our results indicate that frequent activation of Zscan4 can rejuvenate pluripotent stem cells.
Project description:Mouse embryonic stem (ES) cells are locked into self-renewal by shielding from inductive cues. Release from this ground state in minimal conditions offers a system for delineating developmental progression from naive pluripotency. Here we examined the initial transition process. The ES cell population behaves asynchronously. We therefore exploited a short-half-life Rex1::GFP reporter to isolate cells either side of exit from naive status. Differentiation of Rex1-GFPd2 ES cells was initiated by withdrawing 2i (Kalkan et al., 2016). Undifferentiated 2i-cells and post-2i withdrawal differentiating populations (16h, 25h-Rex1-High, 25h-Rex1-Low) were subjected to proteomic analysis by Mass Spectrometry.
Project description:Embryonic (ES) and epiblast (EpiSC) stem cells are pluripotent but committed to an embryonic lineage fate. Conversely, trophoblast (TS) a nd extraembryonic endoderm (XEN) stem cells contribute predominantly to tissues of the placenta and yolk sac, respectively. Here we show that each of these four stem cell types is defined by a unique DNA methylation profile. Despite their distinct developmental origin, TS and XEN cells share key epigenomic hallmarks, chiefly characterized by robust DNA methylation of embryo-specific developmental regulators, as well as a subordinate role of 5-hydroxymethylation. We also observe a substantial methylation reinforcement of pre-existing epigenetic repressive marks that specifically occurs in extraembryonic stem cells compared to in vivo tissue, presumably due to continued high Dnmt3b expression levels. These differences establish a major epigenetic barrier between the embryonic and extraembryonic stem cell types. In addition, epigenetic lineage boundaries also separate the two extraembryonic stem cell types by mutual repression of key lineage-specific transcription factors. Thus, global DNA methylation patterns are a defining feature of each stem cell type that underpin lineage commitment and differentiative potency of early embryo-derived stem cells. Our detailed methylation profiles identify a cohort of developmentally regulated sequence elements, such as orphan CpG islands, that will be most valuable to uncover novel transcriptional regulators and pivotal M-^QM-^QgatekeeperM-^RM-^R genes in pluripotency and lineage differentiation.
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.