Similar Datasets
Project description:Transcriptional responses to wildfire smoke, an increasingly important cause of human morbidity, are poorly understood. Here, using a combination of precision nuclear run-on sequencing (PRO-seq) and the assay for transposase-accessible chromatin using sequencing (ATAC-seq), we identify rapid and dynamic changes in transcription and chromatin structure in Beas-2B airway epithelial cells after exposure to wood smoke particles (WSP). By comparing 30 and 120 minutes of WSP exposure, we defined three distinct temporal patterns of transcriptional induction and chromatin responses to WSP. Whereas transcription of canonical targets of the aryl hydrocarbon receptor (AHR), such as CYP1A1 and AHRR, was robustly increased after 30 minutes of WSP exposure, transcription of these genes and associated enhancers returned to near baseline at 120 minutes. ChIP-qPCR assays and AHR knockdown confirmed a role for AHR in regulating these transcriptional responses, and we applied bioinformatics approaches to identify novel AHR-regulated pathways and targets including the DNA methyltransferase, DNMT3L, and its interacting factor, SPOCD1. Our analysis also defined a role for NFkB as a primary transcriptional effector of WSP-induced changes in gene expression. The kinetics of AHR- and NFkB-regulated responses to WSP were distinguishable based on the timing of both transcriptional responses and chromatin remodeling, with induction of several cytokines implicated in maintaining the NFkB response. In aggregate, our data establish a direct and primary role for AHR in mediating airway epithelial responses to WSP and identify crosstalk between AHR and NFkB signaling in controlling pro-inflammatory gene expression.
2021-02-24 | GSE167371 | GEO
Project description:Transcriptional responses to wildfire smoke, an increasingly important cause of human morbidity, are poorly understood. Here, using a combination of precision nuclear run-on sequencing (PRO-seq) and the assay for transposase-accessible chromatin using sequencing (ATAC-seq), we identify rapid and dynamic changes in transcription and chromatin structure in Beas-2B airway epithelial cells after exposure to wood smoke particles (WSP). By comparing 30 and 120 minutes of WSP exposure, we defined three distinct temporal patterns of transcriptional induction and chromatin responses to WSP. Whereas transcription of canonical targets of the aryl hydrocarbon receptor (AHR), such as CYP1A1 and AHRR, was robustly increased after 30 minutes of WSP exposure, transcription of these genes and associated enhancers returned to near baseline at 120 minutes. ChIP-qPCR assays and AHR knockdown confirmed a role for AHR in regulating these transcriptional responses, and we applied bioinformatics approaches to identify novel AHR-regulated pathways and targets including the DNA methyltransferase, DNMT3L, and its interacting factor, SPOCD1. Our analysis also defined a role for NFkB as a primary transcriptional effector of WSP-induced changes in gene expression. The kinetics of AHR- and NFkB-regulated responses to WSP were distinguishable based on the timing of both transcriptional responses and chromatin remodeling, with induction of several cytokines implicated in maintaining the NFkB response. In aggregate, our data establish a direct and primary role for AHR in mediating airway epithelial responses to WSP and identify crosstalk between AHR and NFkB signaling in controlling pro-inflammatory gene expression.
2021-02-24 | GSE167370 | GEO
Project description:Nascent RNA sequencing defines dynamic aryl hydrocarbon receptor signaling responses to wood smoke particles
| PRJNA704405 | ENA
Project description:Nascent RNA sequencing defines dynamic aryl hydrocarbon receptor signaling responses to wood smoke particles [ATAC-seq]
| PRJNA704406 | ENA
Project description:Nascent RNA sequencing defines dynamic aryl hydrocarbon receptor signaling responses to wood smoke particles [PRO-seq]
| PRJNA704407 | ENA
Project description:Epigenetic modifications to peripheral white blood cell DNA occur in response to a wide variety of exposures. In prior work, we and others have shown that broad changes in DNA methylation, particularly at the aryl hydrocarbon receptor repressor (AHRR) locus, occur in samples from subjects with long histories of smoking. However, given the large number of epigenetic changes that occur in response to prolonged smoking, the primacy of the response at AHRR and the sensitivity of these changes to low levels of smoking are not known. Therefore, we examined the association of smoking to genome lymphocyte DNA methylation status in a representative sample of 399 African American youths living in the rural South that includes 72 subjects with less than one half-pack year of exposure. Consistent with our prior findings, we found a stepwise effect of smoking on DNA methylation among youth with relatively brief exposure histories at a CpG residue in AHRR (cg05575921) (FDR corrected p values; 3 × 10 (-7) and 0.09 in the male and female samples, respectively) that was identified in previous studies and at which the effects of smoking were significant, even in those subjects with less than one half pack year exposure. We conclude that AHRR demethylation at cg05575921 in peripheral cells may serve as an early, sensitive biomarker for even low levels of exposure to tobacco smoke, providing a non-self-report alternative for nascent exposure to tobacco smoke. We also suggest that the AHRR/AHR pathway may be functional in the response of peripheral white blood cells to tobacco smoke exposure.
| S-EPMC3499333 | biostudies-literature
Project description:Aryl hydrocarbon receptor (AhR) is a transcription factor, which can be activated by a plethora of structure-diverse ligands. Historically, AhR is known for its involvements in regulation of metabolism of xenobiotics. However, normal physiological roles of AhR have been defined in other essential biological processes, including vascular growth and function, reproduction, and immunoresponses. In contrast, aberrant expression and activation of the AhR signaling pathway occur in a variety of human diseases, many of which (e.g., preeclampsia, atherosclerosis, and hypertension) could be associated with endothelial dysfunction. Indeed, emerging evidence has shown that either exogenous or endogenous AhR ligands can induce endothelial dysfunction in either an AhR-dependent or AhR-independent manner, possibly reliant on the blood vessel origin (artery and vein) of endothelial cells. Given that the AhR signaling pathway has broad impacts on endothelial and cardiovascular function, AhR ligands, AhR, and their downstream genes could be considered novel therapeutic targets for those endothelial-related diseases. This review will discuss the current knowledge of AhR's mediation on endothelial function and potential mechanisms underlying these actions with a focus on placental endothelial cells.
| S-EPMC7731988 | biostudies-literature
Project description:The aryl hydrocarbon receptor (AHR) plays a central role in the toxic responses to halogenated dibenzo-p-dioxins ("dioxins"), in the metabolic adaptation to polycyclic aromatic hydrocarbons, and in the development of the mature vascular system. A number of lines of evidence support the idea that the regulation of adaptive metabolism requires an AHR partnership with the aryl hydrocarbon receptor nuclear translocator (ARNT). Yet, for AHR-dependent vascular development and dioxin toxicity, the role of ARNT is less certain. In fact, numerous models have been proposed over the years to suggest that the AHR signals in important ways via ARNT-independent events. In an effort to clarify the role of ARNT in AHR-mediated dioxin hepatotoxicity, we generated a conditional Arnt mouse model. Such a model was essential because global inactivation of Arnt results in embryonic lethality presumably due to this protein's role as a heterodimeric partner for the hypoxia-inducible factors (HIFs). Using a hepatocyte-specific Arnt deletion, we were able to demonstrate that hepatocyte ARNT is required for major aspects of AHR-mediated dioxin toxicity in the liver. Results from this conditional Arnt allele are also consistent with a model where hepatocyte ARNT is unrelated to AHR-mediated hepatovascular development. In sum, these data suggest that AHR-ARNT dimers within the hepatocyte direct the toxic and adaptive and developmental functions associated with the AHR and that developmental vascular events arise due to signaling in a distinct cell type expressing this dimeric pair.
| S-EPMC2984536 | biostudies-literature
Project description:Cigarette smoking (CS) is a leading cause of death worldwide. The aryl hydrocarbon receptor (AHR) is partially responsible for tobacco-induced carcinogenesis although the underlying mechanisms involving early effector genes have yet to be determined. Here, we report that adrenomedullin (ADM) significantly contributes to the carcinogenicity of tobacco-activated AHR. CS and AHR activating ligands induced ADM in vitro and in vivo but not in AHR-deficient fibroblasts and mice. Ectopic transfection of AHR rescued ADM expression in AHR(-/-) fibroblasts whereas AHR blockage with siRNA in wild type cells significantly decreased ADM expression. AHR regulates ADM expression through two intronic xenobiotic response elements located close to the start codon in the ADM gene. Using tissue microarrays we showed that ADM and AHR were coupregulated in lung tumor biopsies from smoker patients. Microarray meta-analysis of 304 independent microarray experiments showed that ADM is elevated in smokers and smokers with cancer. In addition, ADM coassociated with a subset of AHR responsive genes and efficiently differentiated patients with lung cancer from nonsmokers. In a novel preclinical model of CS-induced tumor progression, host exposure to CS extracts significantly elevated tumor ADM although systemic treatment with the ADM antagonist NSC16311 efficiently blocked tobacco-induced tumor growth. In conclusion, ADM significantly contributes the carcinogenic effect of AHR and tobacco combustion products. We suggest that therapeutics targeting the AHR/ADM axis may be of clinical relevance in the treatment of tobacco-induced pulmonary malignancies.
| S-EPMC4340077 | biostudies-literature
Project description:In contrast to mammals, zebrafish has high capacity to regenerate tissue architecture and replace lost neurons after traumatic brain injury. The ependymoglia cells react to the injury and generate new neurons, which migrate to the lessoned site and contribute to the tissue restoration. Understanding molecular and cellular mechanisms underlying this regenerative neurogenesis is the crucial step towards achieving regenerative therapies in the mammalian brain. In order to identify molecular pathways governing this mode of restorative neurogenesis, we analysed changes in the transcriptome of ependymoglia cells and their progeny during regeneration process and identified Aryl hydrocarbon receptor (AhR) to be involved in regulation of ependymoglia differentiation towards post-mitotic neurons. Our in vivo imaging analysis shows that the high AhR signalling promotes direct conversion of newly identified population of ependymoglia into the post-mitotic neurons. In contrast, decrease in AhR signalling promotes ependymoglial proliferation. Interestingly, we observed inactivation of the AhR signalling shortly after the injury and return to the basal levels 7 days post injury (dpi) suggesting the role of AhR in proper timing of the direct conversion of ependymoglia, ensuring the successful repair. Taken together, we identified the role of AhR signalling pathway in regulating differentiation of ependymoglia into the neurons and setting up the proper timing of restorative neurogenesis in zebrafish brain.
2018-10-11 | GSE102400 | GEO