Exposure to high levels of arsenic in drinking water is associated with several types of cancers including lung, bladder and skin, as well as vascular disease and diabetes. Drinking water standards are based primarily on epidemiology and extrapolation from higher dose experiments, rather than measurements of phenotypic changes associated with chronic exposure to levels of arsenic similar to the current standard of 10ppb, and little is known about the difference between arsenic in food as opposed to arsenic in water. Measurement of phenotypic changes at low doses may be confounded by the effect of laboratory diet, in part because of trace amounts of arsenic in standard laboratory chows, but also because of broad metabolic changes in response to the chow itself. Finally, this series contrasts 8hr, 1mg/kg injected arsenic with the various chronic exposures, and also contrasts the acute effects of arsenic, dexamethasone or their combination. Male C57BL/6 mice were fed on two commercially available laboratory diets (LRD-5001 and AIN-76A) were chronically exposed, through drinking water or food, to environmentally relevant concentrations of sodium arsenite, or acutely exposed to dexamethasone.
Laboratory diet profoundly alters gene expression and confounds genomic analysis in mouse liver and lung.
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View SamplesThis SuperSeries is composed of the SubSeries listed below.
Identification of the cortical neurons that mediate antidepressant responses.
Specimen part, Treatment
View SamplesSTAT3 is a pleiotropic transcription factor with important functions in cytokine signalling in a variety of tissues. However, the role of STAT3 in the intestinal epithelium is not well understood. Here we demonstrate that development of colonic inflammation is associated with the induction of STAT3 activity in intestinal epithelial cells (IEC). Studies in genetically engineered mice showed that epithelial STAT3 activation in DSS colitis is dependent on IL-22 rather than IL-6. IL-22 was secreted by colonic CD11c+ cells in response to Toll-like receptor stimulation. Conditional knockout mice with an IEC specific deletion of STAT3 activity were highly susceptible to experimental colitis, indicating that epithelial STAT3 regulates gut homeostasis. STAT3IEC-KO mice, upon induction of colitis, showed a striking defect of epithelial restitution. Gene chip analysis indicated that STAT3 regulates the cellular stress response, apoptosis and pathways associated with wound healing in IEC. Consistently, both IL-22 and epithelial STAT3 were found to be important in wound-healing experiments in vivo. In summary, our data suggest that intestinal epithelial STAT3 activation regulates immune homeostasis in the gut by promoting IL-22-dependent mucosal wound healing.
STAT3 links IL-22 signaling in intestinal epithelial cells to mucosal wound healing.
Specimen part
View SamplesToxin A (TcdA) and Toxin B (TcdB), of the pathogen Clostridium difficile, are virulence factors that cause gross pathologic changes (e.g. inflammation, secretion, and diarrhea) in the infected host, yet the molecular and cellular pathways leading to observed host responses are poorly understood. To address this gap, TcdA and/or TcdB were injected into the ceca of mice and the genome-wide transcriptional response of epithelial layer cells was examined. Bioinformatic analysis of gene expression identified sets of cooperatively expressed genes. Further analysis of inflammation associated genes revealed dynamic chemokine responses.
In vivo physiological and transcriptional profiling reveals host responses to Clostridium difficile toxin A and toxin B.
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View SamplesMicroarray analysis was used to compare the gene expression profiles of Deaf-1-transduced mouse mammary epithelial cells (MECs) relative to Deaf-1-deficient MECs.
Deaf-1 regulates epithelial cell proliferation and side-branching in the mammary gland.
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View SamplesWe characterized gene expression changes in the developing mouse liver at gestational days (GD) 11.5, 12.5, 13.5, 14.5, 16.5, and 19.5 and in the neonate (postnatal day (PND) 7 and 30) using full-genome microarrays and compared these changes to that in the adult liver. The fetal liver, and to a lesser extent the neonatal liver, exhibited dramatic differences in gene expression compared to adults. Canonical pathway analysis of the fetal liver signature demonstrated increases in functions important in cell replication and DNA fidelity whereas most metabolic pathways of intermediary metabolism were suppressed. Comparison of the dataset to a number of previously published datasets revealed 1) a striking similarity between the fetal liver and that of the pancreas in both mice and humans, 2) a nucleated erythrocyte signature in the fetus and 3) suppression of most xenobiotic metabolism genes throughout development, except a number of transporters associated with expression in hematopoietic cells.
Transcriptional ontogeny of the developing liver.
Specimen part
View SamplesExtraembryonic trophoblast stem cells (TSC) can be converted to induced pluripotent stem cells (TSC-iPSCs) by overexpressing Oct4, Sox2, Klf4 and cMyc.
Lineage conversion of murine extraembryonic trophoblast stem cells to pluripotent stem cells.
Specimen part
View SamplesTo gain insight into the changes in gene expression pattern upon Ebola infection, CD45+/+ (100% protein level) and CD45+/- (62% protein level) mice were challenged with mouse adapted Ebola virus. At time-points day 0, 1, 3, 5, 7, 9, 11 and 13, spleen tissue was harvested and splenocytes isolated. Total RNA was isolated for mRNA expression analysis. The mouse genome 430 2.0 array (Affymetrix, Inc.), which consists of over 39,000 genes in a single array, was used. Based on gene expression patterns, the variable genes were grouped into sixteen clusters. Each cluster contained genes associated with cellular immune processes, signaling, cell-cycle, complement coagulation cascade, biosynthesis/metabolism, ubiquitous genes involved in several cascades, and genes of unknown function. Interestingly, gene expression in clusters 2 and 3 were significantly downregulated by day 1 following EBOV challenge in CD45100% mice. In contrast, at day 1 following EBOV infection, the CD45 62% mice maintained gene expression patterns similar to day 0. The differences in gene expression patterns between the CD45 100% and CD45 62% splenocytes were less apparent at day 3 following infection and by days 5 and 7 they became very similar. At day 9, when wild-type mice had succumbed to the disease, the pattern in CD45 62% mice remained similar to the day 7 patterns of CD45 100% and CD45 62% mice. The pattern at days 11 and 13 in the CD45 62% mice had returned to that of day 0 CD45 100% or CD45 62% mice. These results suggested that in CD45 100% mice, subversion of the cell transcriptional machinery during the early stages of EBOV infection (day 1) might represent a major factor leading to death of the mice. In CD45 62% mice, early control of gene regulation likely provided the appropriate antiviral responses leading to regulated inflammation, immune co-stimulation, and survival.
Reduced levels of protein tyrosine phosphatase CD45 protect mice from the lethal effects of Ebola virus infection.
Specimen part
View SamplesWe demonstrate that expression of key markers of keratinocyte differentiation is suppressed by exposure to sodium arsenite. Folate deficiency exacerbates this effect. In addition, cancer-related cell movement genes, and growth and proliferation genes are altered. Several redox-sensitive transcription factors are implicated in mediating these gene expression changes due to arsenic treatment and folate deficiency.
Folate deficiency enhances arsenic effects on expression of genes involved in epidermal differentiation in transgenic K6/ODC mouse skin.
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View SamplesFoxp1 is expressed throughout B cell development, but the physiological functions in mature B lymphocytes are unknown. We therefore evaluated differential gene expression in Foxp1-deficient B cells, with or
Foxp1 controls mature B cell survival and the development of follicular and B-1 B cells.
Specimen part
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