AHR ChIP-seq in primary human hepatocytes treated with TCDD
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE205502 | GEO | 2022/06/09
REPOSITORIES: GEO
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Project description:The aryl hydrocarbon receptor (AHR) mediates the toxic effects of environmental contaminants, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Frogs are very insensitive to the toxic effects of TCDD.
2009-06-24 | GSE16670 | GEO
Project description:The aryl hydrocarbon receptor (AHR) mediates the toxic effects of environmental contaminants, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Frogs are very insensitive to the toxic effects of TCDD. Experiment Overall Design: XLK-WG cells (ATCC) were grown to ~90% confluence in RPMI-1640 media supplemented with 20% FBS at 29 degrees and 5% CO2. Cells were subsequently exposed to 100 nM TCDD, FICZ, or DMSO vehicle (0.25%) for 3 hr prior to extraction of total RNA. Experiment Overall Design: Study included three complete biological replicates of each treatment.
2009-07-05 | E-GEOD-16670 | biostudies-arrayexpress
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:2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is a persistent environmental contaminant. Previous reports revealed TCDD activating aryl hydrocarbon receptor (AhR) pathway and causing cardiac damage. However, the mechanism of AhR-induced cardiac defect in response to TCDD exposure remains unclear. In this study, we characterized the impacts of TCDD exposure on heart morphology and cardiac function in zebrafish. To investigate the differentially expressed genes under TCDD exposure, we collected the zebrafish larave heart from the control and TCDD treatment groups. We then performed gene expression profiling analysis using data obtained from RNA-seq. Transcriptomic profiling showed that, along with an upregulation of the AhR signaling pathway by TCDD, the expression of pro-ferroptosis genes was upregulated, while genes implicated in glutathione metabolism were downregulated. Consistently, lipid peroxidation, as indicated by malonaldehyde (MDA) production, increased in TCDD-exposed cardiac tissue. Accordingly, inhibiting lipid peroxidation with Liproxstatin-1 reversed the adverse cardiac effects under TCDD treatment. Together, our findings demonstrate that AhR-mediated lipid peroxidation contributes to the cardiac developmental defects of TCDD during zebrafish early development.
2022-10-30 | GSE206948 | GEO
Project description:Exposures to dioxin, including 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) cause a wide array of toxicities in vertebrates and is mostly considered to be mediated through the inappropriate activation of the aryl hydrocarbon receptor (Ahr) signaling pathway. Although transcriptional regulation by Ahr is widely studied, the molecular mechanisms responsible for the adverse outcomes after Ahr activation are largely unknown. To identify the important events downstream of AHR activation that play an actual role in the toxic responses, we employed the zebrafish caudal fin regeneration models since Ahr activation blocks the regenerative process. Zebrafish regenerate their caudal fins by an orchestrated progression of cell migration, differentiation and proliferation controlled by a multitude of signaling pathways. This complex process was exploited as an in vivo platform to identify cross talk between Ahr and other signaling pathways. Global genomic analysis was performed in the larval regenerating fin tissue after exposure to TCDD in order to identify genes differentially regulated after Ahr activation. Comparative toxicogenomic analysis revealed that both adult and larval fins respond to TCDD during regeneration with mis-expression of Wnt signaling pathway members and Wnt target genes. Experiment Overall Design: The caudal fin of zebrafish larvae at 2days post fertilization were amputated and exposed to vehicle control alone or TCDD. Regenerating fins were isolated at 2and 3 days post amputation. Three replicates were collected at each time point. 150 fins were pooled to comprise one replicate.
2008-04-07 | E-GEOD-10184 | biostudies-arrayexpress
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.
2016-01-01 | GSE72270 | GEO
Project description:Aryl hydrocarbon receptor ChIP-Seq performed in livers of female mice gavaged with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) for 2hrs
2017-04-12 | GSE97636 | GEO
Project description:Aryl hydrocarbon receptor ChIP-Seq performed in livers of male mice gavaged with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) for 2hrs
2017-04-12 | GSE97634 | GEO
Project description:Dioxin-like chemicals are well-known for their ability to upregulate expression of numerous genes via the AH receptor (AHR). However, recent transcriptomic analyses in several laboratories indicate that dioxin-like chemicals or AHR genotype itself also can downregulate levels of mRNAs encoded by numerous genes. The mechanism responsible for such downregulation is unknown. We hypothesized that microRNAs (miRNAs), which have emerged as powerful negative regulators of mRNA levels in several systems, might be responsible for mRNA downregulation in dioxin/AHR pathways. We conducted a thorough investigation to address the following questions: (1) does AHR genotype itself affect constitutive expression of microRNAs? (2) does TCDD affect microRNA levels and, if so, is this response dependent on the AHR? (3) does TCDD affect microRNA levels differently in animals that are sensitive to dioxin toxicity versus those that are dioxin-resistant? We used the Exiqon miRNA array platform as well as quantitative RT-PCR to measure miRNA levels in wildtype vs. Ahr-null mice. Treatment with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in vivo caused few changes in miRNA levels in mouse livers and those changes that were statistically significant were of modest magnitude. AHR genotype had little effect on hepatic miRNA levels, either in constitutive expression or in response to TCDD M-bM-^@M-^S only a few miRNAs differed in expression between Ahr-null mice compared to mice with wildtype AHR. It is unlikely that mRNA downregulation by dioxins is mediated by miRNAs, nor are miRNAs likely to play a significant role in dioxin toxicity in adult mouse liver. Manuscript Submitted: Moffat ID, Boutros PC, Celius T, Pohjanvirta R & Okey AB. Micro-RNAs in rodent liver are refractory to dioxin treatment. Toxicological Sciences May, 2007. Keywords: miRNA expression, gene knockout, response to xenobiotics, genetic modification This was a two-factor, two-level design, the factors being genotype Ahr+/+ (WT) or Ahr-/- (KO) and treatment TCDD-treated (T) or vehicle control (C). Each total-RNA sample was separately labeled either with a Hy3- or a Hy5-fluorophore (Exiqon). Hy3- and Hy5-labeled samples were co-hybridized to an array. Dye-reversal was performed to eliminate dye bias. We tested 3 TCDD-treated and 3 control mice in the Ahr-/- groups and 4 TCDD-treated and 4 control mice in the Ahr+/+ groups. Technical replication of 1 TCDD-treated and 1 control mice in the Ahr-/- groups was performed. A loop design was used.
2007-08-14 | E-GEOD-8468 | biostudies-arrayexpress
Project description:Major toxicities of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) result from dysregulation of gene expression mediated by the aryl hydrocarbon receptor (AHR). Dioxin-like chemicals alter expression of numerous genes in liver but the specific genes whose dysregulation leads to toxicities such as wasting, hepatotoxicity and lethality have not been identified. We searched for genes that are most likely to be key to dioxin toxicity by using gene expression arrays to contrast hepatic gene expression after TCDD treatment in dioxin-sensitive rats (that carry wildtype AHR) with gene expression in H/W(Kuopio) rats which are highly resistant to dioxin toxicity due to a major deletion in the AHR's transactivation domain (TAD). The total number of TCDD-responsive genes was smaller in rats with the AHRH/W genotype than in rats with wildtype AHR. However, genes in the classic AH gene battery such as CYP1A1, CYP1A2 and CYP1B1 remained fully responsive to TCDD in AHRH/W rats; thus the TAD deletion selectively interferes with expression of a subset of hepatic genes rather than abolishing global AHR-mediated responses. Genes in the following functional categories differ in response to TCDD between dioxin-sensitive rats and dioxin-resistant rats: fatty acid oxidation, metabolism (xenobiotic, alcohol, amino acid, and fatty acid), phosphate transport, regulation of steroid biosynthesis, nitrogen compound catabolism, and generation of precursor metabolites and energy. Many of these differentially-responsive genes are integral parts of pathways such as: protein degradation and synthesis, fatty acid metabolism and synthesis, cytokinesis, cell growth, and apoptosis which may be part of mechanisms which lead to TCDD-induced wasting, hepatotoxicity, tumors, and death. These differentially-responsive genes are worthy candidates for further mechanistic studies to test their role in mediating or protecting from major dioxin toxicities. Experiment Overall Design: Four strains of rats were either treated with 100 ug/kg TCDD or cornoil vehicle and profiled at 19 hours, each with four replicates. Two strains were also analyzed at 3 hours, each with four replicates.
2009-12-02 | E-GEOD-10083 | biostudies-arrayexpress