Transcription factor SOX17 overexpression in hematopoietic stem cells
ABSTRACT: This SuperSeries is composed of the following subset Series: GSE30444: Retroviral Sox17 over-expression adult hematopoietic stem/progenitor cells microarray GSE30445: Sox17-transgenic hematopoietic stem cell microarray Refer to individual Series
Project description:The transcription factor SOX17 is expressed by fetal, but not adult hematoipoietic stem cells (HSCs), and is required for the maintenance of fetal and neonatal, but not adult, HSCs. In the current study we show that ectopic expression of Sox17 in adult HSCs and transiently reconstituting multipotent progenitors was sufficient to confer increased self-renewal potential and the expression of fetal HSC genes including fetal HSC surface markers. To assess the mechanisms by which ectopic Sox17 expression in adult hematopoietic progenitors increased self-renewal potential and conferred fetal HSC properties, we compared the gene expression profiles of E16.5 fetal liver HSCs, young adult bone marrow HSCs, young adult bone marrow CD48+LSK cells, and Sox17-expressing CD48+LSK cells isolated from mice that had been transplanted with MSCV-Sox17-infected bone marrow cells 12 weeks earlier. Total RNA (~5ng) was isolated from 3 independent, freshly isolated aliquots of 10,000 E16.5 fetal liver HSCs, 10,000 fetal liver CD48+LSK cells, 10,000 adult bone marrow HSCs, 10,000 adult bone marrow CD48+LSK cells, 10,000 Sox17-expressing CD48+LSK cells isolated from primary recipients 12 weeks after transplantation of MSCV-Sox17-infected bone marrow cells. Purified RNA was reverse transcribed and amplified using the WT-Ovation™ Pico RNA Amplification system (NuGEN Technologies) following the manufacturer’s instructions. Sense strand cDNA was generated using WT-Ovation™ Exon Module (NuGEN), then fragmented and labeled using the FL-Ovation™ cDNA Biotin Module V2 (NuGEN). 2.5µg of labeled cDNA were hybridized to Affymetrix Mouse Gene ST 1.0 microarrays.
Project description:The transcription factor SOX17 is expressed by fetal, but not adult hematoipoietic stem cells (HSCs), and is required for the maintenance of fetal and neonatal, but not adult, HSCs. In the current study we show that ectopic expression of Sox17 in adult HSCs and transiently reconstituting multipotent progenitors was sufficient to confer increased self-renewal potential and the expression of fetal HSC genes including fetal HSC surface markers. To assess the acute effects of ectopic Sox17 expression on global gene expression in adult HSCs, we performed microarray analysis to compare the gene expression profile of adult Sox17-trangenic and control HSCs after short induction of Sox17-transgene expression. Total RNA were isolated from 5 independent, freshly isolated aliquots of 10,000 HSCs isolated from 8-week old Sox17-transgenic ((tetO)7CMVSox17-IRES-NucEGFP;B6.Cg-Gt(ROSA)26Sortm1(rtTA*M2)Jae/J double transgenic) or littermate control mice that were treated with doxycycline for 5 days to induce transgene expression. Purified RNA was reverse transcribed and amplified using the WT-Ovation™ Pico RNA Amplification system (NuGEN Technologies) following the manufacturer’s instructions. Sense strand cDNA was generated using WT-Ovation™ Exon Module (NuGEN), then fragmented and labeled using the FL-Ovation™ cDNA Biotin Module V2 (NuGEN). 2.5µg of labeled cDNA were hybridized to Affymetrix Mouse Gene ST 1.0 microarrays.
Project description:Although Hematopoietic Stem Cell Transplantation (HSCT) routinely treats hematologic disease, many patients experience adverse outcomes. Understanding the molecular regulation of HSC engraftment is paramount to improving HSCT regimens. Here, we executed a large-scale transplant-based functional screen for novel regulators of HSC repopulation.. Of >50 gene candidates tested, 18 were required for in vivo hematopoietic repopulation and two were detrimental to repopulation, as their loss enhanced this activity. Each Hit was validated in a second screen. Eleven Hits have never before been implicated in HSC biology. We further show that one novel Hit, Foxa3, is required for optimal engraftment as Foxa3-/- bone marrow is defective in both primary and secondary hematopoietic reconstitution. We also present evidence that Foxa3 is a novel pioneer factor in HSC. Each gene identified in our screen is a window into the cellular mechanisms that control hematopoietic reconstitution. Thus, this work represents a resource to the community to better understand these processes 3 FOXA3 KO samples are compared to 3 wt samples
Project description:Murine long-term hematopoietic stem cells (HSCs), short-term HSCs and multipotent progenitor cells (MPPs) were isolated from bone marrow and expression profiled on Affy chips. The behavior of maternal-specific imprinting genes, particularly in the H19-Igf2 locus, was focused on, to see if any might be involved in maintaining quiescence of long-term stem cells.
Project description:FoxM1, a mammalian Forkhead Box M1 protein, is known as a typical proliferation-associated transcription factor that regulates of G1/S and G2/M transition in the proliferating cells. However, the in vivo function of FoxM1 in adult stem cells remains unknown. Here, we found that FoxM1 is highly expressed in hematopoietic stem cells (HSCs) and is essential for maintaining quiescence and self-renewal of HSCs in vivo. FoxM1-deficient mice developed leukopenia, thrombocytopenia and neutropenia with an approximately 6-fold decrease in HSC pool size, which is associated with a failure of G0 cell cycle regulation and increased cell cycling in HSCs. FoxM1 absence did not affect lineage commitment of HSCs and progenitors. However, FoxM1 loss significantly reduced the repopulating capacity and self-renewal of long-term HSC in a cell-autonomous manner. Mechanistically, FoxM1 loss markedly down-regulates the expression of orphan nuclear receptor Nurr1, known to regulate HSC quiescence. We found that FoxM1 directly bound the promoter region of Nurr1 and induced transcriptional activity of Nurr1 promoter in vitro, and forced expression of Nurr1 rescued FoxM1-deletion-induced G0 loss of HSC-enriched population in vitro. Thus, our studies show a previously unrecognized role of FoxM1 as a critical regulator of HSC quiescence and self-renewal by controlling Nurr1-mediated pathways. The Hematopoietic Stem Cells (HSCs) were sorted from FoxM1[fl/fl] and Tie2-Cre FoxM1[fl/fl] mice, then amplified with Ovation Pico WTA System V2 before microarray analysis. There are 3 samples from FoxM1[fl/fl]mice and 3 samples from Tie2-Cre FoxM1[fl/fl] mice.
Project description:Canonical Wnt signalling regulates the self-renewal of most if not all stem cell systems. In the blood system, the role of Wnt signalling has been subject of much debate, with positive and negative roles of Wnt signalling proposed for hematopoietic stem cells (HSC). As we have shown previously, this controversy can be largely explained by the effects of different dosages of Wnt signalling. What remained unclear however, was why high Wnt signals would lead to loss of reconstituting capacity. To better understand this phenomenon, we have taken advantage of a series of hypomorphic mutant Apc alleles resulting in a broad range of Wnt dosages in HSCs, purified those HSCs and performed whole genome gene expression analyses. Gene expression profiling and functional studies show that HSCs with APC mutations lead to high Wnt levels , enhanced differentiation and diminished proliferation, but have no effect on apoptosis, collectively leading to loss of stemness. Thus, we provide mechanistic insight into the role of APC mutations and Wnt signalling in HSC biology. As Wnt signals are explored in various in vivo and ex vivo expansion protocols for HSCs, our findings also have clinical ramifications. To investigate the effects of Wnt signals in hematopoietic cells, mice carrying floxed Apc or hypomorphic Apc mutants were crossed, LSK cells were isolated and treated with Cre IRES GFP gamma-retrovirus ex vivo, GFP+ cells were sorted and RNA expression was determined.
Project description:Secretion of insulin by pancreatic β cells in response to glucose is central for glucose homeostasis, and dysregulation of this process is a hallmark of the early stages of diabetes. We utilized a tetracycline-inducible approach to investigate the immediate impact of a pulse of Sox17 expression on the insulin secretory pathway. Sox17 gain-of-function animals (Sox17-GOF) were generated using an Ins2-rtTA mouse line and a line in which Sox17 expression is regulated by the tetracycline transactivator (tetO-Sox17). Administering doxycycline to 16-week old mice resulted in Sox17 overexpression in mature β cells in the islets. In order to identify the molecular basis by which Sox17 regulates the secretory pathway in β cells, we performed microarray analysis on isolated islets following a 24-hour pulse of Sox17 overexpression. We chose to analyze a 24 hour pulse of Sox17 for islet pancreas RNA extraction and hybridization on Affymetrix microarrays since it was sufficient to stimulate the insulin secretory pathway without causing changes in islet architecture.
Project description:Mouse embryonic stem cells containing a Sox17-GFP construct were differentiated using growth factors (Activin A and Wnt3A) to definitive endoderm. Sox17-GFP(+) cells were sorted using fluorescence activated cell sorting and either used for total RNA harvest OR continued in culture in the presence of primary pancreatic mesenchymal cell lines. At the end of 6 serial passages on mesenchyme, the Sox17-GFP(+) cells were again sorted and the RNA was harvested for arrays. Samples were prepared as described in summary, with technical duplicates for each of the following 3 categories: 1. Unpassaged (P0) endoderm, 2. Endoderm passaged 6 times (P6) on mesenchyme 1, and 3. Endoderm passaged 6 times (P6) on mesenchyme 2.
Project description:We identified the ubiquitin ligase Huwe1 as a crucial regulator of hematopoietic stem cell (HSC) functions. We generated Huwe1 conditional knock-out mice and discovered that the loss of this ligase causes an increased proliferation and stem cell exhaustion, together with a decreased lymphoid specification in vivo. We observed that the ubiquitin ligase Huwe1 is controlling the expression of N-myc at the level of the most immature stem and progenitor hematopoietic populations, mediating the described effects. Hematopoietic stem cells (HSC) from the bone marrow of transgenic animals carrying a N-myc/mCherry fusion gene were sorted according to N-myc expression (defined by mCherry) into N-myc high and low subpopulations. Each of these 2 populations was subjected to microarray gene expression profiling.
Project description:Hematopoietic stem cell (HSC) differentiation is regulated by cell-intrinsic and extrinsic cues. In addition to transcriptional regulation, post-translational regulation may also control HSC differentiation. To test this hypothesis, we visualized ubiquitin-regulated protein stability of a single transcription factor, c-Myc. The stability of c-Myc protein was instructive of HSC quiescence and c-Myc protein abundance was controlled by the ubiquitin ligase Fbw7. Fine changes in stability of c-Myc protein regulated the HSC “gene expression signature”. Using whole genome genomic approaches, we identified specific regulators of HSC function that are directly controlled by c-Myc binding, however adult HSCs and embryonic stem cells sense and interpret distinctly c-Myc regulated gene expression. These studies show a ubiquitin ligase–substrate pair can orchestrate the molecular program of HSC differentiation. Gene expression profiles from c-Myc-High and c-Myc-Low expressing Lineage negative, c-Kit and Sca1 positive (LSKs) were compared using genome wide mRNA expression profiling by Affymetrix genechip arrays (Mouse 430 2.0) and key targets were validated by chromatin immunoprecipitation experiments.