Mus musculus
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PROVIDER: PRJNA382533 | ENA |
REPOSITORIES: ENA
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Project description:AHR ChIP-Seq of female mouse liver following 2 hour TCDD exposure
| PRJNA382532 | ENA
Project description:The aryl hydrocarbon receptor (AHR) mediates most of the toxic effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). However, TCDD toxicity phenotypes vary widely between species, strains and even between sexes within a strain. While the exact reasons for this variation remain unclear, it is thought to be related to differences in the structure of the AHR. Previous studies comparing the downstream effects of TCDD exposure between animals with different AHR isoforms have been confounded by the genetic differences between these model systems. To address this issue conclusively, we evaluated three transgenic mouse lines, each of which express a different rat AHR isoform (rWT, DEL, and INS) from two strains of rat with highly divergent TCDD-susceptibilities, within identical genetic backgrounds. Here we profile hepatic transcriptomic responses following exposure to TCDD, and use these to identify transcripts associated with toxicity. We have confirmed that the variation in toxicity is inherent to the AHR isoform. Additionally, we note the enhanced activity of the modified transactivation domain of the DEL isoform, relative to the INS isoform, and provide further evidence that the INS isoform is responsible for the high resistance to TCDD observed in H/W rats. We also uncover several candidate genes that were consistently differentially expressed in TCDD-sensitive mice and rats. Adult male transgenic mice were treated by gavage with 0, 125, 250, 500, or 1000 µg/kg TCDD dissolved in corn oil vehicle. Mice were euthanized 4 days following treatment and liver tissue was harvested for analysis. RNA was isolated and the transcriptome for each animal assayed on separate microarrays.
2016-07-03 | E-GEOD-72270 | biostudies-arrayexpress
Project description:Environmental contaminants such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), are known to cause a wide range of toxicities. The consequences of acute exposure to TCDD in rodents, and to a lesser degree in humans, can range from mild chloracne to terminal illness, such as cancer. The aryl hydrocarbon receptor (AHR) plays a critical role in mediating the toxic effects of TCDD. However, the underlying mechanism of differential sensitivities to TCDD across organisms remain poorly understood, however differences in the AHR are known to play a role. To further investigate this, we profiled the transcriptomic responses in liver from TCDD sensitive or resistant mice, 19 hours following exposure to either 5 or 500 μg/kg TCDD. Analysis of transcriptomic profiles revealed several key findings: 1) TCDD sensitive C57BL/6 mice demonstrated an increased number of changes within the hepatic transcriptome than the TCDD resistant DBA/2 mice following exposure to low dose (5 μg/kg) TCDD, but this balanced out at the high dose (500 μg/kg), and the transcriptome from ratonized mice showed more changes than either C57BL/6 or DBA/2, regardless of dose; 2) mRNA abundance of the ‘AHR-core’ battery of genes was consistently perturbed in dioxin sensitive mice (C57BL/6 and rWT) in comparison to dioxin resistant mice (DBA/2), with Inmt showing significant changes in transcription only in the ratonized mouse liver and Cyp1a2 more response in non-transgenic mice (C57BL/6 and DBA/2); 3) a small subset of genes had significantly altered transcription in either the TCDD-resistant DBA/2 mouse liver (including Rpl18a, Mbd6, Onecut2 and Lipg) or the TCDD-sensitive cohorts (C57BL/6 and rWT; including Smcp, Acpp, Acot2 and Acot3). Overall, our results demonstrate considerable TCDD-induced transcriptomic differences between DBA/2 and C57BL/6 mouse lines.
2019-10-29 | GSE127217 | GEO
Project description:The aryl hydrocarbon receptor (AHR) agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) alters differentiation of B cells and suppresses antibody production. The objectives of this study was to use a combination of whole genome, microarray-based chromatin immunoprecipitation (ChIP-on-chip) and time course gene expression microarray analysis on the mouse B-cell line CH12.LX following exposure to lipopolysaccharide (LPS) or LPS and TCDD to identify the primary and downstream transcriptional elements of B-cell differentiation that are altered by the AHR.
2010-09-01 | GSE23708 | GEO
Project description:TCDD is an environmental contaminant that elicits a number of hepatic effects including fat accumulation, inflammation, and fibrosis that can progress to hepatocellular carcinoma. RNA-Seq and targeted metabolomics were integrated with complementary dioxin response element (DRE) location and aryl hydrocarbon receptor (AhR) ChIP-Seq data to further investigate the hepatotoxicity of TCDD. Our integrative analysis identified changes similar to the Warburg effect observed in cancer cells, including pyruvate kinase isoform switching (PKM1 to PKM2), and an increase in the glutaminase (GLS1) GAC:KGA isoform ratio. Consequently, metabolites are redirected towards the pentose phosphate pathway, serine biosynthesis, and glutaminolysis. We propose that the effects of TCDD on central carbon and amino acid metabolism represents AhR-mediated hepatic metabolic reprogramming in order to increase NADPH production as an oxidative stress counter-measure.
2017-02-02 | MTBLS225 | MetaboLights
Project description:2,3,7,8–tetrachlorodibenzo-p-dixion (TCDD) is the most potent of the dioxin congeners, capable of causing a wide range of toxic effects across numerous animal models. Previous studies have demonstrated that males and females of the same species can display divergent sensitivity phenotypes to TCDD toxicities. Although it is now clear that most TCDD-induced toxic outcomes are mediated by the aryl hydrocarbon receptor (AHR), the mechanism of differential responses to TCDD exposure between sexes remains largely unknown. To investigate the differential sensitivities in male and female mice, we profiled the hepatic transcriptomic responses 4 days following exposure to various amounts of TCDD (125, 250, 500 or 1000 µg/kg) in adult male and female C57BL/6Kuo mice. Several key findings were revealed by our study. 1) Hepatic transcriptomes varied significantly between the sexes at all doses examined. 2) The liver transcriptome of males was more dysregulated by TCDD than that of females. 3) The alteration of ‘AHR-core’ genes was consistent in magnitude, regardless of sex. 4) A subset of genes demonstrated sex-dependent TCDD-induced transcriptional changes, including Fmo3 and Nr1i3, which were significantly induced in livers of male mice only. In addition, a meta-analysis was performed to contrast transcriptomic profiles of various organisms and tissues following exposure to equitoxic doses of TCDD. Minimal overlap was observed in the differences between TCDD-sensitive or TCDD-resistant models. Sex-dependent sensitivities to TCDD exposure are associated with a set of sex-specific TCDD-responsive genes. In addition, complex interactions between the aryl hydrocarbon and sex hormone receptors may affect the observable differences in sensitivity phenotypes between the sexes. Further work is necessary to better understand the roles of those genes altered by TCDD in a sex-dependent manner, and their association with changes to sex hormones and receptors.
2015-03-01 | GSE61038 | GEO
Project description:Exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces hepatic oxidative stress following activation of the aryl hydrocarbon receptor (AhR). Our recent studies revealed induction of pyruvate kinase muscle isoform 2 (Pkm2) as a novel antioxidant response in normal differentiated hepatocytes. To investigate cooperative regulation between nuclear factor, erythroid derived 2, like 2 (Nrf2) and the AhR, hepatic ChIP-seq analyses were integrated with RNA-seq time course data from mice treated with TCDD for 2 - 168h. ChIP-seq analysis 2h following TCDD treatment revealed genome-wide changes in NRF2 binding. 842 NRF2 enriched regions were in the regulatory region of differentially expressed genes (DEGs) while 579 DEGs showed both NRF2 and AhR enrichment. Sequence analysis showed over-representation of AhR and NRF2 binding motifs in these regions, though presence of motifs were largely independent. NRF2 was negligibly enriched within the Pkm gene loci in a closed chromatin region despite its role in antioxidant defenses. Furthermore, TCDD induced Pkm2 in primary hepatocytes from wild-type and Nrf2 null mice, indicating NRF2 is not required. Although NRF2 and AhR cooperate in the regulation of gene expression associated with antioxidant responses, the induction of Pkm2 by TCDD is not dependent on ROS-mediated activation of NRF2.
2018-06-07 | GSE109865 | GEO
Project description:Exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces hepatic oxidative stress following activation of the aryl hydrocarbon receptor (AhR). Our recent studies revealed induction of pyruvate kinase muscle isoform 2 (Pkm2) as a novel antioxidant response in normal differentiated hepatocytes. To investigate cooperative regulation between nuclear factor, erythroid derived 2, like 2 (Nrf2) and the AhR, hepatic ChIP-seq analyses were integrated with RNA-seq time course data from mice treated with TCDD for 2 - 168h. ChIP-seq analysis 2h following TCDD treatment revealed genome-wide changes in NRF2 binding. 842 NRF2 enriched regions were in the regulatory region of differentially expressed genes (DEGs) while 579 DEGs showed both NRF2 and AhR enrichment. Sequence analysis showed over-representation of AhR and NRF2 binding motifs in these regions, though presence of motifs were largely independent. NRF2 was negligibly enriched within the Pkm gene loci in a closed chromatin region despite its role in antioxidant defenses. Furthermore, TCDD induced Pkm2 in primary hepatocytes from wild-type and Nrf2 null mice, indicating NRF2 is not required. Although NRF2 and AhR cooperate in the regulation of gene expression associated with antioxidant responses, the induction of Pkm2 by TCDD is not dependent on ROS-mediated activation of NRF2.
2018-06-07 | GSE109863 | GEO
Project description:Conventional biochemical and molecular techniques identified previously several genes whose expression is regulated by the aryl hydrocarbon receptor (AHR). We sought to map the complete spectrum of AHR-dependent genes in male adult liver using expression arrays to contrast mRNA profiles in Ahr-null mice (Ahrâ/â) with those in mice with wild-type AHR (Ahr+/+). Transcript profiles were determined both in untreated mice and in mice treated 19 h earlier with 1000 µg/kg 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Expression of 456 ProbeSets was significantly altered by TCDD in an AHR-dependent manner, including members of the classic AHRE-I gene battery, such as Cyp1a1, Cyp1a2, Cyp1b1, and Nqo1. In the absence of exogenous ligand, AHR status alone affected expression of 392 ProbeSets, suggesting that the AHR has multiple functions in normal physiology. In Ahrâ/â mice, only 32 ProbeSets exhibited responses to TCDD, indicating that the AHR is required for virtually all transcriptional responses to dioxin exposure in liver. The flavin-containing monooxygenases, Fmo2 and Fmo3, considered previously to be uninducible, were highly induced by TCDD in an AHR-dependent manner. The estrogen receptor alpha as well as two estrogen-receptor-related genes (alpha and gamma) exhibit AHR-dependent expression, thereby extending cross-talk opportunities between the intensively studied AHR and estrogen receptor pathways. p53 binding sites are over-represented in genes down-regulated by TCDD, suggesting that TCDD inhibits p53 transcriptional activity. Overall, our study identifies a wide range of genes that depend on the AHR, either for constitutive expression or for response to TCDD. Experiment Overall Design: Mice bearing wild-type or genetically deleted AHRs were treated with corn oil vehicle or TCDD, and their livers analyzed by expression arrays.
2008-11-13 | E-GEOD-10082 | biostudies-arrayexpress
Project description:Conventional biochemical and molecular techniques identified previously several genes whose expression is regulated by the aryl hydrocarbon receptor (AHR). We sought to map the complete spectrum of AHR-dependent genes in male adult liver using expression arrays to contrast mRNA profiles in Ahr-null mice (Ahr–/–) with those in mice with wild-type AHR (Ahr+/+). Transcript profiles were determined both in untreated mice and in mice treated 19 h earlier with 1000 µg/kg 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Expression of 456 ProbeSets was significantly altered by TCDD in an AHR-dependent manner, including members of the classic AHRE-I gene battery, such as Cyp1a1, Cyp1a2, Cyp1b1, and Nqo1. In the absence of exogenous ligand, AHR status alone affected expression of 392 ProbeSets, suggesting that the AHR has multiple functions in normal physiology. In Ahr–/– mice, only 32 ProbeSets exhibited responses to TCDD, indicating that the AHR is required for virtually all transcriptional responses to dioxin exposure in liver. The flavin-containing monooxygenases, Fmo2 and Fmo3, considered previously to be uninducible, were highly induced by TCDD in an AHR-dependent manner. The estrogen receptor alpha as well as two estrogen-receptor-related genes (alpha and gamma) exhibit AHR-dependent expression, thereby extending cross-talk opportunities between the intensively studied AHR and estrogen receptor pathways. p53 binding sites are over-represented in genes down-regulated by TCDD, suggesting that TCDD inhibits p53 transcriptional activity. Overall, our study identifies a wide range of genes that depend on the AHR, either for constitutive expression or for response to TCDD. Keywords: treatment-control and mutant-wildtype
2008-11-01 | GSE10082 | GEO