The mitochondrial superoxide dismutase (SOD2) is a major antioxidant protein which detoxifies superoxide anion radicals generated by mitochondrial respiration (Weisiger and Fridovich, J. Biol. Chem. 1973). We designed a model of oxidative stress-induced anemia caused by SOD2-deficiency (Friedman et al. J. Exp. Med. 2001). Our previous work showed that mice reconstituted with SOD2-deficient hematopoietic stem cells develop an anemia with striking similarity to human sideroblastic anemia (SA) (Friedman et al. Blood 2004; Martin et al. Exp Hematol 2005). Our overall goal was to define early events in the pathogenesis of SOD2-deficiency SA and, in particular, to identify genes involved in the response of erythroid progenitors to oxidative stress. We compared gene expression of sorted TER-119+ CD71+ erythroblasts from SOD2-/- ('KO') versus Sod2+/+ ('WT') hematopoietic stem cell recipients using cDNA microarrays.
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View SamplesInteraction of hematopoietic progenitors with the thymic stromal microenvironment induces them to proliferate, adopt the T cell fate, and asymmetrically diverge into multiple T lineages. Progenitors at various developmental stages are stratified among different regions of the thymus, implying that the corresponding microenvironments differ from one another, and provide unique sets of signals to progenitors migrating between them. The nature of these differences remains undefined. Here we use novel physical and computational approaches to characterize these stromal subregions, distinguishing gene expression in microdissected tissues from that of their lymphoid constituents. Using this approach, we comprehensively map gene expression in functionally distinct stromal microenvironments, and identify clusters of genes that define each region. Quite unexpectedly, we find that the central cortex lacks distinctive features of its own, and instead appears to function by sequestering unique microenvironments found at the cortical extremities, and modulating the relative proximity of progenitors moving between them.
Spatial mapping of thymic stromal microenvironments reveals unique features influencing T lymphoid differentiation.
Specimen part
View SamplesSalivary glands are essential structures that secrete saliva to the oral cavity and maintain oral health. Development of salivary glands in mice and humans is controlled by mesenchymally expressed fibroblast growth factor-10 (FGF10). Using single cell RNA-seq atlas of the salivary gland and a tamoxifen inducible Fgf10CreERT2:R26-tdTomato mouse we show that FGF10pos cells are exclusively mesenchymal until postnatal day 5 (P5), but after P7, there is a switch in expression and only epithelial FGF10pos cells are observed after P15. Further RNAseq analysis of sorted mesenchymal and epithelial FGF10pos cells shows that the epithelial FGF10pos populations express the hallmark of ancient ionocyte signature Foxi1, Foxi2, Ascl3 and the cystic fibrosis transmembrane conductance regulator (Cftr). We propose that epithelial FGF10pos cells are specialized salivary gland ionocytes that are important for the ionic modification of saliva. In addition, they maintain FGF10-dependent glands homeostasis via communication with FGFR2b-expressing epithelial progenitor and myoepithelial cells Overall design: Comparison of Fgf10+ expressing cell mRNA profiles from submandibular glands of 7 day old pups and 60 days old mice in duplicate
A mesenchymal to epithelial switch in Fgf10 expression specifies an evolutionary-conserved population of ionocytes in salivary glands.
Specimen part, Genotype, Subject
View SamplesBackground
Expression quantitative trait loci mapping identifies new genetic models of glutathione S-transferase variation.
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View SamplesCardiac hypertrophy can lead to heart failure, and is induced either by physiological stimuli eg postnatal development, chronic exercise training or pathological stimuli eg pressure or volume overload. Majority of new therapies for heart failure has mixed outcomes. A combined mouse model and oligo-array approach are used to examine whether phosphoinositide 3-kinase (p110-alpha isoform) activity is critical for maintenance of cardiac function and long-term survival in a setting of heart failure. The significance and expected outcome are to recognise genes involved in models of heart failure ie pathological- vs physiology-hypertrophy, and examine the molecular mechanisms responsible for such activity.
PI3K(p110 alpha) protects against myocardial infarction-induced heart failure: identification of PI3K-regulated miRNA and mRNA.
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View SamplesWe identified an endothelial progenitor/stem like population in the endothelial fraction of preexsiting blood vessels.
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Age, Specimen part
View SamplesHigh-throughput gene expression profiling has become an important tool for investigating transcriptional activity in a variety of biological samples. To date, the vast majority of these experiments have focused on specific biological processes and perturbations. Here, we profiled gene expression from a diverse array of normal tissues, organs, and cell lines in mice. Keywords: multiple tissues
Expression analysis of G Protein-Coupled Receptors in mouse macrophages.
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View SamplesRegeneration of differentiated tissue in mammals is rare. In an effort to identify genes that affect the healing process, we screened G3 mice containing germline point mutations for closure of an ear punch wound. One particular line was identified with a heritable hole closure phenotype containing differentiated tissue. Mapping and sequencing efforts revealed that the mutant mice harbor a R244Q point mutation coded by the TGFBR1 gene which leads to enhanced signaling activity in a reporter gene assay. Although there was no obvious effect on the immune system, bone marrow stromal cells from the mutant mice revealed accelerated chondrogenesis, mimicking the in vivo development of cartilage islands in the regenerated ears. This genetically well-defined mouse model should help to further dissect the role of TGF-beta signaling in vertebrate healing and regeneration.
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View SamplesNew insulin-producing pancreatic beta-cells are formed primarily by self-replication during adult life. To identify small molecules that can induce beta cell replication, a large chemical library was screened for proliferation of growth-arrested, reversibly immortalized mouse beta-cells using an automated high-throughput screening platform. A number of structurally diverse, active compounds were identified including phorbol esters, which likely act through protein kinase C, and a group of thiophene-pyrimidines that stimulate beta-cell proliferation by activating the Wnt signaling pathway. A group of dihydropyridine (DHP) derivatives was also shown to reversibly induce beta-cell replication in vitro by activating L-type calcium channels (LTCCs). Our data indicate that the LTCC agonist 2a affects the expression of genes involved in cell cycle progression and cellular proliferation. Furthermore, treatment of beta-cells with both LTCC agonist 2a and the Glp-1 receptor agonist Ex-4 showed an additive effect on beta-cell replication. The identification of small molecules that induce beta-cell proliferation suggests that it may be possible to reversibly expand other quiescent cells to overcome deficits associated with degenerative and/or autoimmune diseases.
Identification of small-molecule inducers of pancreatic beta-cell expansion.
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View SamplesThe two vertebrate Gsk-3 isoforms, Gsk-3a and Gsk-3b, are encoded by distinct genetic loci and exhibit mostly redundant function in murine embryonic stem cells (ESCs). Here we report that deletion of both Gsk-3a and Gsk-3b in mouse ESCs results in significant changes in gene expression. In contrast, deletion of either Gsk-3a or Gsk-3b individually had little effect on gene expression. These data support the notion that Gsk-3 isoforms are functionally redundant in embryonic stem cells. In addition, we did not find the expected upregulation of known Wnt target genes. Our data suggests that Gsk-3-meidated regulation of gene expression in embryonic stem cells is complex, and likely involves affects on numerous signaling pathways.
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Specimen part
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