Dysregulated Wnt signalling is seen in approximately 30% of hepatocellular cancers, thus finding pathways downstream of activation of Wnt signalling is key. Using cre lox technology we have deleted the the adenomatous polyposis coli tumour suppressor protein (Apc) within the adult mouse liver and observed a rapid increase in nuclear beta-catenin and C-Myc. This is associated with an induction of proliferation leading to hepatomegally within 4 days of gene deletion. To investigate the downstream pathways responsible for these phenotypes we analysed the impact of inactivating Apc in the context of deficiency of the potentially key effectors beta-catenin and c-Myc. beta-catenin loss rescues both the proliferation and hepatomegally phenotypes following Apc loss. However c-Myc deletion, which rescues the phenotypes of Apc loss in the intestine, had no effect on the phenotypes of Apc loss. The consequences of deregulation the Wnt pathway within the liver are therefore strikingly different to those observed within the intestine, with the vast majority of Wnt targets beta-catenin dependent but c-Myc independent in the liver.
B-catenin deficiency, but not Myc deletion, suppresses the immediate phenotypes of APC loss in the liver.
No sample metadata fields
View SamplesWe sequenced liver mRNA isolated from biliatresone-treated zebrafish larvae and DMSO-treated controls in order to elucidate the molecular pathways induced by biliatresone, a biliary toxin that is responsible for outbreaks of biliary atresia in Australian liverstock. Overall design: Liver mRNA profiles of biliatresone-treated zebrafish larvae and DMSO-treated controls were generated by deep sequencing, in duplicates.
Glutathione antioxidant pathway activity and reserve determine toxicity and specificity of the biliary toxin biliatresone in zebrafish.
No sample metadata fields
View SamplesSphingosine 1-phosphate (S1P) is a bioactive lipid whose levels are tightly regulated by its synthesis and degradation. Intracellularly, S1P is dephosphoryled by the actions of two S1P-specific phosphatases, sphingosine 1-phosphate phosphatase 1 and 2. To identify the physiologic functions of S1P phosphatase 1, we have studied mice with its gene, Sgpp1, deleted. Sgpp1-/- mice appeared normal at birth but during the first week of life, they exhibited stunted growth, suffered desquamation, and most died before weaning. Interestingly, the epidermal permeability barrier developed normally during embryogenesis. Sgpp1 -/- pups and surviving adults exhibited epidermal hyperplasia and abnormal expression of keratinocyte differentiation markers. Keratinocytes isolated from Sgpp1 -/- skin had increased intracellular S1P levels, and expressed a gene expression profile that indicated enhanced differentiation. The results reveal S1P metabolism as a regulator of keratinocyte differentiation and epidermal homeostasis.
Sphingosine-1-phosphate phosphatase 1 regulates keratinocyte differentiation and epidermal homeostasis.
Specimen part
View SamplesFoxp3+ regulatory T (Treg) cells prevent inflammatory disease but the mechanistic basis of suppression is not understood completely . Gene silencing by RNA interference can act in a cell-autonomous and non-cell-autonomous manner, providing mechanisms of inter-cellular regulation. Here, we demonstrate that non-cell-autonomous gene silencing, mediated by miRNA-containing exosomes, is a mechanism employed by Treg cells to suppress T cell-mediated disease. Treg cells transferred microRNAs (miRNA) to various immune cells, including T helper 1 (Th1) cells, suppressing Th1 cell proliferation and cytokine secretion. Use of Dicer-deficient or Rab27a and Rab27b double-deficient Treg cells to disrupt miRNA-biogenesis or the exosomal pathway, respectively, established a requirement for miRNAs and exosomes for Treg cell-mediated suppression. Transcriptional analysis and miRNA inhibitor studies showed that exosome-mediated transfer of Let-7d from Treg cell to Th1 cells contributed to suppression and prevention of systemic disease. These studies reveal a mechanism of Treg cell-mediated suppression mediated by miRNA-containing exosomes.
MicroRNA-containing T-regulatory-cell-derived exosomes suppress pathogenic T helper 1 cells.
Specimen part
View SamplesWe compared gene expression differences in Lyl-1 knockout vs wildtype LMPPs
The transcription factor Lyl-1 regulates lymphoid specification and the maintenance of early T lineage progenitors.
Specimen part
View SamplesAnalysis of HSCs from control and c-myc N-myc deficient long-term hematopoietic stem cells. HSCs lacking both c-myc and N-myc display increased apoptosis rates. Data provide insight into the molecular changes occuring upon complete loss of Myc activity, clarifying the resulting apoptotic mechanism and the role of Myc family proteins in HSCs and commited progenitors.
Hematopoietic stem cell function and survival depend on c-Myc and N-Myc activity.
Age, Specimen part
View SamplesAnalysis of HSCs from control and c-myc N-myc deficient long-term hematopoietic stem cells. HSCs lacking both c-myc and N-myc display increased apoptosis rates. Data provide insight into the molecular changes occuring upon complete loss of Myc activity, clarifying the resulting apoptotic mechanism and the role of Myc family proteins in HSCs.
Hematopoietic stem cell function and survival depend on c-Myc and N-Myc activity.
Age, Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Hematopoietic stem cell function and survival depend on c-Myc and N-Myc activity.
Age, Specimen part
View SamplesWe isolated fetal murine urogenital sinus epithelium and urogenital sinus mesenchyme and determined their global gene expression profiles to define their differentially expressed regulators. To distinguish gene expression patterns that are shared by other developing epithelial/mesenchymal compartments in the embryo from those that pertain to the prostate stem cell niche, we also determine the global gene expression of epidermis and dermis of the same embryos. We identified a distinctive core of transcripts that were differentially regulated in the prostate stem cell niche. Our analysis indicates that several of the key transcriptional components that are likely to be active in the embryonic prostate stem cell niche regulate processes such as self-renewal (e.g., E2f and Ap2), lipid metabolism (e.g., Serbp1) and cell migration (e.g., Areb6 and Rreb1). Several of the promoter binding motifs that are enriched in the profiles are shared between the prostate epithelial/mesenchymal compartments and their epidermis/dermis counterparts, indicating their likely relevance in epithelial/mesenchymal signaling in primitive cellular compartments. We also focused on defining ligand-receptor interactions that may be relevant in controlling signals in the stem cell niche and identified the Wnt/beta-catenin, ephrin, Notch, sonic hedgehog, FGF, TGF-beta and bone morphogenic signaling pathways as being of likely relevance in the prostate stem cell niches. Members of the integrins family including those that bind extracellular matrix proteins such as laminin and activate latent TGF-beta are also expressed in the prostate niche.development.
Molecular signatures of the primitive prostate stem cell niche reveal novel mesenchymal-epithelial signaling pathways.
No sample metadata fields
View SamplesBone marrow hematopoietic stem cells (HSCs) are crucial to maintain lifelong production of all blood cells. Although HSCs divide infrequently, it is thought that the entire HSC pool turns over every few weeks, suggesting that HSCs regularly enter and exit cell cycle. Here, we combine flow cytometry with label-retaining assays (BrdU and histone H2B-GFP) to identify a population of dormant mouse HSCs (d-HSCs) within the lin(-)Sca1+cKit+CD150+CD48(-)CD34(-) population. Computational modeling suggests that d-HSCs divide about every 145 days, or five times per lifetime. d-HSCs harbor the vast majority of multilineage long-term self-renewal activity. While they form a silent reservoir of the most potent HSCs during homeostasis, they are efficiently activated to self-renew in response to bone marrow injury or G-CSF stimulation. After re-establishment of homeostasis, activated HSCs return to dormancy, suggesting that HSCs are not stochastically entering the cell cycle but reversibly switch from dormancy to self-renewal under conditions of hematopoietic stress
Hematopoietic stem cells reversibly switch from dormancy to self-renewal during homeostasis and repair.
Specimen part, Time
View Samples