We investigated the ability of transferrin receptor1 (TfRc) knockout cells to populate different domains of the developing kidney by using a chimeric approach. The TfRc cells developed into all segments of the developing nephron, but there was a relative exclusion from the ureteric bud and a positive bias towards the stromal compartment. Here we conducted a microarray analysis of differential gene expression between TfRc deficient and wild type (wt) cells in chimeric embryonic kidneys derived from embryos created by blastocyst injection of wt blastocysts with TfRc-/- green fluorescent protein-expressing (GFP+) embryonic stem cells.
Scara5 is a ferritin receptor mediating non-transferrin iron delivery.
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View SamplesHuman Immunodeficiency Virus (HIV) associated nephropathy (HIVAN) is characterized clinically by both nephrosis and by rapidly progressive kidney dysfunction. HIVAN is characterized histologically by both collapsing focal segmental glomerulosclerosis and prominent tubular damage. Neutrophil Gelatinase Associated Lipocalin (NGAL) is known to be rapidly expressed in distal segments of the nephron at the onset of different types of acute kidney injury, but few studies have examined NGAL in chronic kidney disease models. We found that urinary NGAL (uNGAL) was highly expressed by patients with biopsy proven HIVAN, whereas HIV+ patients without HIVAN demonstrated lower levels. uNGAL was also highly expressed in the TgFVB mouse model of HIVAN, which demonstrated NGAL gene expression in dilated, microcystic segments of the nephron. These data show that NGAL is markedly upregulated in the setting of HIVAN, and suggest that uNGAL levels may provide a non-invasive screening test to detect HIVAN related tubular disease.
Urinary NGAL marks cystic disease in HIV-associated nephropathy.
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View SamplesThe gastrointestinal (GI) tract can have significant impact on the regulation of the whole body metabolism and may contribute to the development of obesity and diabetes. To systemically elucidate the role of the GI tract in obesity, we performed a transcriptomic analyses in different parts of the GI tract of two obese mouse models: ob/ob and high-fat diet (HFD) fed mice. Compared to their lean controls, both obese mouse groups had significant amount of gene expression changes in the stomach (ob/ob: 959; HFD: 542), much more than the number of changes in the intestine. Despite the difference in genetic background, the two mouse models shared 296 similar gene expression changes in the stomach. Among those genes, some had known associations to obesity, diabetes and insulin resistance. In addition, the gene expression profile strongly suggested an increased gastric acid secretion in both obese mouse models, probably through an activation of the gastrin pathway. In conclusion, our data reveal a previously unknown dominant connection between the stomach and obesity.
Significant obesity-associated gene expression changes occur in the stomach but not intestines in obese mice.
Specimen part
View SamplesBACKGROUND: p53 is an important tumor suppressor with a known role in the later stages of colorectal cancer, but its relevance to the early stages of neoplastic initiation remains somewhat unclear. Although p53-dependent regulation of Wnt signalling activity is known to occur, the importance of these regulatory mechanisms during the early stages of intestinal neoplasia has not been demonstrated.
A limited role for p53 in modulating the immediate phenotype of Apc loss in the intestine.
Specimen part
View SamplesDysregulated 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.
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View SamplesmiR-155 transgenic mice develop pre-B cell leukemia/lymphoma. Though some targets of miR-155 are known, understanding of the mechanism by which miR-155 overexpression drives malignant transformation is not known. MicroRNAs regulate multiple genes.
miR-155 targets histone deacetylase 4 (HDAC4) and impairs transcriptional activity of B-cell lymphoma 6 (BCL6) in the Eμ-miR-155 transgenic mouse model.
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View SamplesEphB receptors regulate the proliferation and positioning of intestinal stem and progenitor cells. In addition, they can act as tumor promoters for adenoma development, but suppress progression to invasive carcinoma. Here we used imatinib to abrogate Abl kinase activity in ApcMin/+ mice and in mice with LGR5+ stem cells genetically targeted for APC. This treatment inhibited the tumor-promoting effects of EphB signaling without attenuating EphB-mediated tumor suppression, demonstrating the role of EphB signaling in intestinal tumor initiation. The investigated treatment regimen extended the lifespan of ApcMin/+ mice, and reduced cell proliferation in cultured slices of adenomas from FAP patients. These findings connect the EphB signaling pathway to the regulation of intestinal adenoma initiation via Abl kinase. Our findings may have clinical implications for pharmacological therapy against adenoma formation and cancer progression in patients predisposed to develop colon cancer.
An EphB-Abl signaling pathway is associated with intestinal tumor initiation and growth.
Specimen part
View SamplesRb and E2F are thought to play antagonistic roles in celll proliferation. However, this model is based mostly from in vitro cell culture systems. We used small intestines to test this model in vivo.
E2f1-3 switch from activators in progenitor cells to repressors in differentiating cells.
Age, Specimen part
View SamplesAffymetrix microarrays were used to determine the mRNA composition of mRNPs obtained by immunoprecipitation with IRP2 (iron regulatory protein 2).
Identification of target mRNAs of regulatory RNA-binding proteins using mRNP immunopurification and microarrays.
Sex
View SamplesThe goal of this experiment was to define gene expression patterns of two mouse retinal neuron subsets that express the Thy1-mitoCFP-P (MP) transgene.
Neurod6 expression defines new retinal amacrine cell subtypes and regulates their fate.
Specimen part
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