Tight regulation of hematopoietic stem cell (HSC) homeostasis is essential for life-long hematopoiesis, for preventing blood cancers and for averting bone marrow failure. The underlying mechanisms are incompletely understood. Here, we identify production of inositol-tetrakisphosphate (IP4) by inositoltrisphosphate 3-kinase B (ItpkB) as essential for HSC quiescence and function. Young ItpkB-/- mice accumulated phenotypic HSC and showed extramedullary hematopoiesis. ItpkB-/- HSC were less quiescent and proliferated more than wildtype controls. They downregulated quiescence and stemness associated mRNAs, but upregulated activation, oxidative metabolism, protein synthesis and lineage associated transcripts. Although they showed no significant homing defects, ItpkB-/- HSC had a severely reduced competitive long-term repopulating potential. Aging ItpkB-/- mice lost hematopoietic stem and progenitor cells and died with severe anemia. Wildtype HSC normally repopulated ItpkB-/- hosts, incidating a HSC-intrinsic ItpkB requirement. ItpkB-/- HSC had reduced cobblestone-area forming cell activity in vitro and showed increased stem-cell-factor activation of the phosphoinositide 3-kinase (PI3K) effector Akt, reversed by exogenous provision of the known PI3K/Akt antagonist IP4. They also showed transcriptome changes consistent with hyperactive Akt/mTOR signaling. Thus, we propose that ItpkB ensures HSC quiescence by limiting cytokine-induced PI3K signaling in HSC. Overall design: For each of 3 replicate ItpkB-/- or wt samples, we enriched Lin- cells from BM of 4 pooled age-matched mice with Rapidspheres (Stemcell Technologies), FACS-sorted =10,000 LSK CD34-CD150+CD48-Flk2- LT-HSC into lysis buffer and prepared RNA with RNeasy Micro kits (Quiagen). RNA sequencing was done using an Illumina HISeq Analyzer 2000, Casava v1.8.2 genome analyzer pipeline, TopHat v1.4.1/Bowtie2 genome alignment and Partek v6.6 mRNA annotation software. Statistical analyses were done with edgeR (Bioconductor package), excluding genes with false discovery rates >0.15, fold-change magnitudes =1.4 and log2(counts per million) =4 to avoid undefined values and the poorly defined log fold-changes for low counts close to 0. Unsupervised clustering of 441 significantly changed genes was done with dChip using rank correlation and a centroid linkage method. Scatter plots were generated in Spotfire. GSEA was performed with gene set permutation, using gene sets from MSigDB (www.broadinstitute.org/gsea/msigdb/index.jsp) or manually curated from, excluding genes without HUGO approved symbols
IP3 3-kinase B controls hematopoietic stem cell homeostasis and prevents lethal hematopoietic failure in mice.
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View SamplesMore than two thirds of breast cancers express the estrogen receptor (ER) and depend on estrogen for growth and survival. Therapies targeting ER function including aromatase inhibitors that block the production of estrogens and ER antagonists that alter ER transcriptional activity play a central role in the treatment of ER+ breast cancers of all stages. In contrast to ER- breast cancers, which frequently harbor mutations in the p53 tumor suppressor, ER+ breast cancers are predominantly wild type for p53. Despite harboring wild type p53, ER+ breast cancer cells are resistant to chemotherapy-induced apoptosis in the presence of estrogen. Using genome-wide approaches we have addressed the mechanism by which ER antagonizes the pro-apoptotic function of p53. Interestingly both ER agonists such as estradiol and selective ER modulators (SERM) such as tamoxifen promote p53 antagonism. In contrast the full ER antagonist fulvestrant blocks the ability of ER to inhibit p53-mediated cell death. This suggests an improved strategy for the treatment of ER+ breast cancer utilizing antagonists that completely block ER action together with drugs that activate p53-mediated cell death.
Estrogen receptor prevents p53-dependent apoptosis in breast cancer.
Cell line, Treatment
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Clonal Variation in Drug and Radiation Response among Glioma-Initiating Cells Is Linked to Proneural-Mesenchymal Transition.
Specimen part, Cell line
View SamplesIntra-tumor heterogeneity is a hallmark of glioblastoma multiforme, and thought to negatively affect treatment efficacy. Here we establish libraries of glioma-initiating cell (GIC) clones from patient samples and find extensive molecular and phenotypic variability between clones, including a wide range of responses to radiation and drugs. This widespread variability was observed as a continuum of multitherapy resistance phenotypes linked to a proneural-to-mesenchymal shift in the transcriptome.
Clonal Variation in Drug and Radiation Response among Glioma-Initiating Cells Is Linked to Proneural-Mesenchymal Transition.
Specimen part, Cell line
View SamplesEstrogen has vascular protective effects in premenopausal women and in women under 60 receiving hormone replacement therapy. However, estrogen also increases risks of breast and uterine cancers and of venous thromboses linked to upregulation of coagulation factors in the liver. In mouse models, the vasoprotective effects of estrogen are mediated by the estrogen receptor alpha (ERa) transcription factor. Here, through next generation sequencing approaches, we show that almost all of the genes regulated by 17-b-estradiol (E2) differ between mouse aorta and mouse liver, and that this is associated with a distinct genomewide distribution of ERa on chromatin. Bioinformatic analysis of E2-regulated promoters and ERa binding site sequences identify several transcription factors that may determine the tissue specificity of ERa binding and E2-regulated genes, including the enrichment of NFkB, AML1 and AP-1 sites in the promoters of E2 downregulated inflammatory genes in aorta but not liver. The possible vascular-specific functions of these factors suggests ways in which the protective effects of estrogen could be promoted in the vasculature without incurring negative effects in other tissues. Our results also highlight the likely importance of rapid signaling of membrane-associated ERa to cellular kinases (altering the activities of transcription factors other than ER itself) in determining tissue specific transcriptional responses to estrogen. Overall design: The aortas or liver fragments of wild-type C57/BL6 mice were incubated ex vivo with 10nM E2 or ethanol vehicle for 4 hours before harvesting for RNA collection. Each condition was performed with two biological replicates, and each replicate contained aortas or liver fragments from 4 mice.
Research resource: Aorta- and liver-specific ERα-binding patterns and gene regulation by estrogen.
No sample metadata fields
View SamplesSpinal cord injury leads to impaired motor and sensory functions. After spinal cord injury there is a an initial phase of hypo-reflexia followed by a developing hyper-reflexia, often termed spasticity. Previous studies have suggested a relationship between the reappearence of plateau potentials in motor neurons and the development of spasticity after spinalization. To understand the molecular mechanism behind this phenomenon we examined the transcriptional response of the motor neurons after spinal cord injury.
Global gene expression analysis of rodent motor neurons following spinal cord injury associates molecular mechanisms with development of postinjury spasticity.
Sex
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Polo-Like Kinase 3 Appears Dispensable for Normal Retinal Development Despite Robust Embryonic Expression.
Specimen part
View SamplesThese data investigate the transcriptomic differences in the whole retinas of mice resulting from loss of Polo-like Kinase 3 (Plk3) over various stages of development, including adulthood, postnatal day (P)7, and P0.
Polo-Like Kinase 3 Appears Dispensable for Normal Retinal Development Despite Robust Embryonic Expression.
Specimen part
View SamplesAnalysis of adult retinas from tripartite motif-containing domain 9 knockouts and wild type littermates. Trim9 belongs to the TRIM family of E3 ubiquitin ligases. Results provide insight into possible roles for Trim9 in the retina.
The Trim family of genes and the retina: Expression and functional characterization.
Specimen part
View SamplesThese data investigate the transcriptomic differences in the whole retinas of mice resulting from loss of Polo-like Kinase 3 (Plk3) at embryonic day (E)16.
Polo-Like Kinase 3 Appears Dispensable for Normal Retinal Development Despite Robust Embryonic Expression.
Specimen part
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