Dioxin and AHR impairs mesoderm gene expression and cardiac differentiation in human embryonic stem cells (ChIP-Seq)
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE122001 | GEO | 2018/10/31
REPOSITORIES: GEO
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Project description:Dioxin and dioxin-related polychlorinated biphenyls are potent toxicants with association with developmental heart defects and congenital heart diseases. However, the underlying mechanism of their developmental toxicity is not fully understood. Further, different animals show distinct susceptibility and phenotypes after exposure, suggesting possible species-specific effects. Using a human embryonic stem cell (ESC) cardiomyocyte differentiation model, we examined the impact, susceptible window, and dosage of 2,3,7,8‑tetrachlorodibenzo‑p‑dioxin (TCDD) on human cardiac development. We showed that treatment of human ESCs with TCDD at the ESC stage inhibits cardiomyocyte differentiation, and the effect is largely mediated by the aryl hydrocarbon receptor (AHR). We further identified genes that are differentially expressed after TCDD treatment by RNA-sequencing, and genomic regions that are occupied by AHR by chromatin immunoprecipitation and high-throughput sequencing. Our results support the model that TCDD impairs human ESC cardiac differentiation by promoting AHR binding and repression of key mesoderm genes. More importantly, our study demonstrates the toxicity of dioxin in human embryonic development and uncovered a novel mechanism by which dioxin and AHR regulates lineage commitment. It also illustrates the power of ESC-based models in the systematic study of developmental toxicology.
2018-10-31 | GSE122002 | GEO
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:The aryl hydrocarbon receptor (AHR) is a ligand activated transcription factor that mediates the toxic effects of the environmental contaminant, dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin; TCDD). Dioxin causes a diverse range of toxic responses, including hepatic damage and lethal wasting syndrome; however, the mechanisms of dioxin-induced toxicity are still unknown. Here we show that the loss of TCDD-inducible poly(ADP-ribose) polymerase (TIPARP; ARTD14), an ADP-ribosyltransferase and AHR repressor, increases sensitivity to dioxin-induced toxicity and lethality. Tiparp-/- mice treated with a single injection of 100 mg/kg dioxin display an accelerated lethal wasting syndrome with no Tiparp-/- mice surviving beyond day 5; all Tiparp+/+ mice survived up to 30 days post treatment. Tiparp-/- mice displayed dramatic increases in liver steatosis and hepatotoxicity. At the molecular level, TIPARP selectively ADP-ribosylates AHR, but not AHR nuclear translocator (ARNT) and the Tiparp-dependent repression of AHR is reversed by the ADP-ribosylase and macrodomain containing protein MacroD1, but not MacroD2. These results describe previously unidentified roles for Tiparp, MacroD1, and ADP-ribosylation in AHR signaling, dioxin toxicity and lethality.
2015-05-14 | GSE61534 | 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: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 used the Exiqon miRNA array platform as well as quantitative RT-PCR to measure miRNA levels in dioxin-sensitive Long-Evans (Turku/AB; L-E) rats vs. dioxin-resistant Han/Wistar(Kuopio; H/W) rats. Treatment with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in vivo caused few changes in miRNA levels in rat 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 – only a few miRNAs differed in expression between between L-E rats (that have wildtype AHR) compared to H/W rats (whose AHR has a large deletion in the transactivation domain). 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 rodent liver. 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 assessed the in vivo effect of TCDD on microRNA levels in liver at multiple time points after TCDD treatment using microRNA arrays along with quantitative RT-PCR. The cumulative results of our experiments indicate that downregulation of mRNA levels by dioxins in adult rodent livers is very unlikely to involve microRNAs. 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, Time course, response to xenobiotics, genetic modification, comparative genome hybridization We examined strain differences in miRNA expression independent of TCDD: 19-h vehicle-treated dioxin-resistant H/W AHRH/W/H/W rats (HC19) vs. vehicle- control dioxin-sensitive L-E AHRWT/WT rats (LC19). In the dioxin-sensitive rats we compared miRNA expression levels 3 h (LT3) or 19 h (LT19) post-TCDD treatment vs. LC19. In the dioxin-resistant rats we compared miRNA levels 3 h (HT3), 19 h (HT19), or 96 h (HT96) post-TCDD treatment vs. HC19.
2007-08-15 | E-GEOD-8470 | biostudies-arrayexpress
Project description:The aryl hydrocarbon receptor (AHR) is a ligand activated transcription factor that mediates the toxic effects of the environmental contaminant, dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin; TCDD). Dioxin causes a diverse range of toxic responses, including hepatic damage and lethal wasting syndrome; however, the mechanisms of dioxin-induced toxicity are still unknown. Here we show that the loss of TCDD-inducible poly(ADP-ribose) polymerase (TIPARP; ARTD14), an ADP-ribosyltransferase and AHR repressor, increases sensitivity to dioxin-induced toxicity and lethality. Tiparp-/- mice treated with a single injection of 100 mg/kg dioxin display an accelerated lethal wasting syndrome with no Tiparp-/- mice surviving beyond day 5; all Tiparp+/+ mice survived up to 30 days post treatment. Tiparp-/- mice displayed dramatic increases in liver steatosis and hepatotoxicity. At the molecular level, TIPARP selectively ADP-ribosylates AHR, but not AHR nuclear translocator (ARNT) and the Tiparp-dependent repression of AHR is reversed by the ADP-ribosylase and macrodomain containing protein MacroD1, but not MacroD2. These results describe previously unidentified roles for Tiparp, MacroD1, and ADP-ribosylation in AHR signaling, dioxin toxicity and lethality. 12 samples were analyzed. There were 4 treatment groups and each treatment group was done in triplicate. Gene expression changes were determine in hepatic RNA isolated from (1) corn oil treated C57BL/6;129Sv mice; (2) 30 ug/kg/bw 2,3,7,8-Tetrachlorodibenzo-p-dioxin C57BL/6;129Sv mice; (3) corn oil treated C57BL/6;129Sv Tiparp-/- mice; and (4) 30 ug/kg/bw 2,3,7,8-Tetrachlorodibenzo-p-dioxin C57BL/6;129Sv Tiparp-/- mice
2015-05-14 | E-GEOD-61534 | biostudies-arrayexpress
Project description:The aryl hydrocarbon receptor (AHR) is a ligand activated transcription factor that regulates the expression of xenobiotic detoxification genes and is a critical mediator of gene-environment interactions. In addition, many AHR target genes that have been identified by genome-wide profiling have morphogenetic functions, suggesting that AHR activation may play a role in embryonic development. To address this hypothesis, we studied the consequences of AHR activation by TCDD, its prototypical ligand, during spontaneous mouse ES cell differentiation into contractile cardiomyocytes. Treatment with TCDD or shRNA-mediated AHR knockdown significantly decreased the ability of cardiomyocytes to contract and the expression of cardiac markers in these cells. An AHR-positive embryonic stem cell lineage was generated that expressed puromycin resistance and eGFP under the control of the AHR-responsive Cyp1a1 promoter. Cells of this lineage were over 90% pure and expressed AHR as well as cardiomyocyte markers. Analysis of temporal trajectories of global gene expression in these cells shows that activation of the AHR/TCDD axis disrupts the concerted expression of genes that regulate multiple signaling pathways involved in cardiac and neural morphogenesis and differentiation, including dozens of genes encoding homeobox transcription factors and Polycomb and Trithorax Group genes. More than 50% of the homeobox factors so regulated do not have AhRE sites in their promoters, indicating that AHR activation may establish a complex regulatory network that reaches beyond direct AHR signaling and is capable of disrupting various aspects of embryonic development, including cardiomyocyte differentiation. mRNA profiles of WT and selected AHR positive cells at different differentiation days treated with and without TCDD in duplicates
2013-06-15 | E-GEOD-47964 | 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
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 – 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
2007-08-15 | GSE8468 | GEO
Project description:Aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor, which mediates the effects of various environmental contaminants, like polycyclic and halogenated aromatic hydrocarbons, including the most potent agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), in multiple tissues. Recent advances in AHR biology have underlined its importance in cells with high developmental potency, including pluripotent stem cells. Nonetheless, there is little data on AHR expression and its role during the initial stages of stem cell differentiation. The purpose of this study was to investigate the temporal pattern of AHR expression during directed differentiation of human embryonic stem cells (hESC) into neural progenitor, early mesoderm and definitive endoderm cells. Additionally, we studied the effect of AHR agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on gene expression profile in hESCs and differentiated cells by RNA-seq, accompanied by identification of AHR binding sites by ChIP-seq and epigenetic landscape analysis by ATAC-seq. . We show that AHR is differentially regulated in distinct lineages, provide evidence that TCDD impairs differentiation of hESCs and identify novel potential AHR target genes which expand our understanding on the role of this protein in different cell types.
2020-12-03 | GSE160980 | GEO