Project description:The aim of this study was to analyse the heterogeneity within the first haematopoietic stem cells generated during mouse development using single-cell RNA-Seq. Freshly dissected aorta-gonads-mesohenphros (AGM) regions from E11.5 mouse embryos were dissociated by collagenase and the cells stained for the cell surface markers EPCR and CD45. EPCR+CD45+ cells were index-sorted as single cells into 96-well plates and processed based on the SmartSeq2 protocol. PCA and tSNE analyses identified 2 main subpopulations which are segregated based on differences in cell cycle. Known HSC markers such as Gata2 and Runx1 show little correlation.
Project description:<p>Sertoli cell-only syndrome is severe form of human male infertility in which most seminiferous tubules appear to lack all spermatogenic cells, including spermatogonial stem cells (SSCs). However, a few small tubule segments of some patients have active spermatogenesis and, thus, functional stem cell niches and SSCs. Normally SSCs replicate, migrate and refill adjacent empty niches, but this does not appear to occur in SCO syndrome. We hypothesized that this failure occurs because most niches are dysfunctional. As Sertoli cells are essential to formation of these niches, we used RNAseq to compare the transcriptomes of human testes with qualitatively normal (complete) spermatogenesis (n=4) with the transcriptomes of human testes with SCO syndrome (n=7). We then focused our analysis on the expression of transcripts that bioinformatic analyses identified as Sertoli cell signature transcripts. Results show that Sertoli cells in SCO testes express abnormally low levels of GDNF, FGF8 and BMP4, all of which are important regulators of mouse SSCs and/or progenitor spermatogonia. Sertoli cells in SCO testes express significantly reduced levels of transcripts for proteins that polarize the Sertoli cell plasma membrane and regulate the trafficking of cell adhesion and gap junction proteins in and out of that plasma membrane.</p>
Project description:By tracing the VE-cadherin expression in the newborn bone marrow hematopoietic LSK (lineage minus/Sca-positive/Kit-positive) cells, we demonstrated that the late foetal/newborn BM hemogenic endothelial cells produce a small cohort of hematopoietic stem and progenitor cells (HSPCs) capable of circulating and colonizing the secondary haematopoietic organs. Phenotypic and functional analyses disclosed that BM endothelium-derived HSPCs are mainly Multipotent Progenitors (MPPs) and a few Hematopoietic Stem Cells. We used microarrays to detail the global programme of gene expression underlying the endothelial origin of LSK cells in the newborn bone marrow.
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:Chimeric embryos were generated to investigate the effect of Tal1 knockout in mouse embryos by single-cell RNA-sequencing. Tal1 is an essential transcription factor for the formation of the embryonic blood. Embryo chimerism permits the analysis of the effects of Tal1 knockout without the confounding effects of the absence of embryonic blood, which results in global developmental failures. Embryos were generated by blastocyst injection of tdTomato-labelled, Tal1-/- mouse embryonic stem cells into wild type embryos. After blastocyst harvest, cells were flow-sorted before 10X Genomics library preparation and single-cell RNA-sequencing.
Project description:Chimeric embryos were generated to investigate the effect of Tal1 knockout in mouse embryos by single-cell RNA-sequencing. Tal1 is an essential transcription factor for the formation of the embryonic blood. Embryo chimerism permits the analysis of the effects of Tal1 knockout without the confounding effects of the absence of embryonic blood, which results in global developmental failures. Embryos were generated by blastocyst injection of tdTomato-labelled, Tal1-/- mouse embryonic stem cells into wild type embryos. After blastocyst harvest, cells were flow-sorted before 10X Genomics library preparation and single-cell RNA-sequencing.
Project description:The discovery of significant heterogeneity in the self-renewal durability of adult haematopoietic stem cells (HSCs) has challenged our understanding of the molecules involved in population maintenance throughout life. Gene expression studies in bulk populations are difficult to interpret since multiple HSC subtypes are present and HSC purity is typically less than 50% of the input cell population. Numerous groups have therefore turned to studying gene expression profiles of single HSCs, but again these studies are limited by the purity of the input fraction and an inability to directly ascribe a molecular program to a durable self-renewing HSC. Here we combine single cell functional assays with flow cytometric index sorting and single cell gene expression assays to gain the first insight into the gene expression program of HSCs that possess durable self-renewal. This approach can be used in other stem cell systems and sets the stage for linking key molecules with defined cellular functions. single-cell RNA-Seq of haematopoietic stem cells
Project description:Find the casual relationship between gene expression network and cellular phenotype at single cell resolution. We collected donated human pre-implatation embryos, and the embryonic stem cells derived from them, isolate individual cells, prepared single cell cDNAs, and sequenced them by HiSeq2000. Then we analyzed the expression of known RefSeq genes. We get transcriptome of 124 individual cells from human pre-implantation embryos and human embryonic stem cells by applying single cell RNA-seq technique we recently developed[1][2][3][4]. We did in-depth bioinformatic analysis to these data and found very dynamic expression of protein-coding genes. [1] Tang, F. et al. (2010a) Tracing the Derivation of Embryonic Stem Cells from the Inner Cell Mass by Single-Cell RNA-Seq Analysis. Cell Stem Cell 6, 468-478. [2] Tang, F. et al. (2010b) RNA-Seq analysis to capture the transcriptome landscape of a single cell. Nat Protocols 5, 516-535. [3] Tang, F. et al. (2009) mRNA-Seq whole-transcriptome analysis of a single cell. Nat Meth 6, 377-382. [4] Tang, F. et al. (2011) Development and applications of single-cell transcriptome analysis. Nat Meth 8, S6-S11.
Project description:Combinatorial transcription factor (TF) interactions control cellular phenotypes and therefore underpin stem cell formation, maintenance and differentiation. Here we report the genome-wide binding patterns and combinatorial interactions for 10 key regulators of blood stem/progenitor cells (Scl/Tal1, Lyl1, Lmo2, Gata2, Runx1, Meis1, Pu.1, Erg, Fli-1, Gfi1b) thus providing the most comprehensive TF dataset for any adult stem/progenitor cell type to date. Genome-wide computational analysis of complex binding patterns followed by functional validation revealed the following: First, a previously unrecognized combinatorial interaction between a heptad of TFs (Scl, Lyl1, Lmo2, Gata2, Runx1, Erg, Fli-1). Second, we implicate direct protein-protein interactions between four key regulators (Runx1, Gata2, Scl, Erg) in stabilising complex binding to DNA. Third, Runx1+/-::Gata2+/- compound heterozygous mice are not viable with severe haematopoietic defects at midgestation. Taken together, this study demonstrates the power of genome-wide analysis in generating novel functional insights into the transcriptional control of stem and progenitor cells. 10 Samples (9 Transcription Factors and 1 Histone Modification) and 1 Control (IgG). All from the same cell line, a haematopoietic progenitor cell line (HPC-7).