Effect of constitutive AHR activation in skeletal muscle
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE225607 | GEO | 2023/06/08
REPOSITORIES: GEO
Similar Datasets
Project description:To investigate the RNA differences in skeletal muscle in muscle-specific AHR (aryl hydrocarbon receptor) knockout mice and their AHR-floxed littermate controls (wildtype) following a 16-week chronic cigarette smoke exposure intervention
2024-02-20 | GSE225670 | GEO
Project description:BRAF oncogene is mutated in ~50% of human cutaneous melanomas. The BRAF V600E mutation leads to constitutive activation of the mitogen-activated protein kinase (MAPK) pathway fuelling cancer growth. The inhibitors of BRAF V600E (BRAFi), lead to massive and high response rate. However, BRAFi-resistant cells that operate as a cellular reservoir for relapses severely limits the duration of the clinical response. The recent depiction of these resistant cells did not identify druggable targets to ensure long-term survival under BRAFi. Here, we identify the aryl hydrocarbon receptor (AhR) as a target to eradicate resistant cells. We show that BRAFi bind to AhR on a new site, named beta-pocket, and reprogram gene expression independently of its partner ARNT. beta-pocket activation induces a pigmentation signature, which is associated to BRAFi-induced cell death of sensitive BRAF V600E melanoma cells and tumour shrinkage. Intriguingly, in resistant cells, BRAFi does not induced a pigmentation signature since these cells display another AhR program; AhR-ARNT dependant. By this way, AhR directs several key BRAFi-resistant genes. At single cell level, this constitutive activation of AhR-ARNT is identified in rare cells before BRAFi-treatment of melanoma tumours and an enrichment of these alpha-cells is observed under BRAFi. Our data strongly suggest that an endogenous AhR ligand activates AhR-ARNT via the canonical AhR pocket (alpha-pocket), thus favouring BRAFi-resistant gene expression. Importantly, we identify the clinically compatible AhR antagonist, the resveratrol (RSV), able to abrogate the deleterious constitutive activation of AhR and to reduce the cellular reservoir for the relapse. Taken together, this work reveals that constitutive AhR signalling drives BRAFi resistance and constitutes a therapeutic target to achieve long-term patient survival under BRAFi. More broadly, the constitutive activation of AhR by endogenous ligands is in line with the ability of UV radiations to generate potent AhR ligands and to favour melanoma onset.
2018-11-29 | GSE104869 | GEO
Project description:Occupational and environmental exposure to polycyclic aromatic hydrocarbons (PAHs) has been suggested to provoke inflammatory and/or allergic disorders including asthma, rhinitis and dermatitis. The molecular mechanisms of this PAH-mediated inflammation remain to be clarified. Previous studies implied the involvement of PAHs as irritants and allergens, with the reactive oxygen species generated from the oxygenated PAHs believed to be an exacerbating factor. As well, the possibility exists that PAHs contribute to the pathogenesis through activation of aryl-hydrocarbon receptor (AhR)-mediated transcription, since PAHs are potent inducers of the AhR. To address this point, we generated transgenic mouse lines expressing the constitutive active form of the AhR in keratinocytes. In these lines of mice, the AhR activity was constitutively enhanced in the absence of ligands, so that any other direct effects of PAHs and their metabolites could be ignored. At birth, these transgenic mice were normal, but severe skin lesions with itching developed postnatally. The skin lesions were accompanied by inflammation and immunological imbalance and resembled typical atopic dermatitis. Our present study demonstrates that constitutive activation of the AhR pathway causes inflammatory skin lesions and suggests a new mechanism for the exacerbation of inflammatory diseases following exposure to occupational and environmental xenobiotics. Experiment Overall Design: transgenic mice expressing constitutive active form of AhR in keratinocytes vs. non-transgenic mice (wild type littermates)
2008-06-12 | E-GEOD-2955 | biostudies-arrayexpress
Project description:Occupational and environmental exposure to polycyclic aromatic hydrocarbons (PAHs) has been suggested to provoke inflammatory and/or allergic disorders including asthma, rhinitis and dermatitis. The molecular mechanisms of this PAH-mediated inflammation remain to be clarified. Previous studies implied the involvement of PAHs as irritants and allergens, with the reactive oxygen species generated from the oxygenated PAHs believed to be an exacerbating factor. As well, the possibility exists that PAHs contribute to the pathogenesis through activation of aryl-hydrocarbon receptor (AhR)-mediated transcription, since PAHs are potent inducers of the AhR. To address this point, we generated transgenic mouse lines expressing the constitutive active form of the AhR in keratinocytes. In these lines of mice, the AhR activity was constitutively enhanced in the absence of ligands, so that any other direct effects of PAHs and their metabolites could be ignored. At birth, these transgenic mice were normal, but severe skin lesions with itching developed postnatally. The skin lesions were accompanied by inflammation and immunological imbalance and resembled typical atopic dermatitis. Our present study demonstrates that constitutive activation of the AhR pathway causes inflammatory skin lesions and suggests a new mechanism for the exacerbation of inflammatory diseases following exposure to occupational and environmental xenobiotics. Keywords: transcriptional activation
2005-10-01 | GSE2955 | GEO
Project description:Atopic dermatitis is increasing worldwide, correlating with air pollutions. Various organic components of pollutants activate transcription factor AhR (aryl-hydrocarbon receptor). We have established AhR-CA mice, whose keratinocytes express constitutive-active AhR, and these mice developed atopic dermatitis-like frequent scratching and allergic inflammation. In this study we performed ChIP-seq analyses and identified keratinocyte-specific AhR target genes, including inflammatory cytokines Tslp and IL33, and neurotrophic factor Artemin. While AhR-CA mice exhibited epidermal hyperinnervation and alloknesis leading to hypersensitivity to pruritus, blockade of Artemin alleviated these phenotypes. AhR-CA mice showed scratching-induced barrier insufficiency and enhanced sensitization to epicutaneously-applied antigens, recapitulating human atopic dermatitis. Consistently, AhR activation and Artemin expression was detected in the epidermis of atopic dermatitis patients and keratinocytes exposed to air pollutants. Thus, AhR in keratinocytes senses the environmental stimuli and responds to them through moderating inflammation. We propose a mechanism in which air pollution induces atopic dermatitis through AhR activation.
2016-11-13 | GSE72449 | GEO
Project description:Atopic dermatitis is increasing worldwide, correlating with air pollutions. Various organic components of pollutants activate transcription factor AhR (aryl-hydrocarbon receptor). We have established AhR-CA mice, whose keratinocytes express constitutive-active AhR, and these mice developed atopic dermatitis-like frequent scratching and allergic inflammation. In this study we performed ChIP-seq analyses and identified keratinocyte-specific AhR target genes, including inflammatory cytokines Tslp and IL33, and neurotrophic factor Artemin. While AhR-CA mice exhibited epidermal hyperinnervation and alloknesis leading to hypersensitivity to pruritus, blockade of Artemin alleviated these phenotypes. AhR-CA mice showed scratching-induced barrier insufficiency and enhanced sensitization to epicutaneously-applied antigens, recapitulating human atopic dermatitis. Consistently, AhR activation and Artemin expression was detected in the epidermis of atopic dermatitis patients and keratinocytes exposed to air pollutants. Thus, AhR in keratinocytes senses the environmental stimuli and responds to them through moderating inflammation. We propose a mechanism in which air pollution induces atopic dermatitis through AhR activation.
2016-11-13 | GSE72455 | 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:The transcriptional program of early embryonic development is tightly regulated by a set of well-defined transcription factors that suppress premature expression of differentiation genes and sustain the pluripotent identity. It is generally accepted that this program can be perturbed by environmental factors such as chemical pollutants, however the precise molecular mechanisms remain unknown. The Aryl Hydrocarbon Receptor (AHR) is a widely expressed nuclear receptor that senses environmental stimuli and modulates target gene expression. Here, we show that ectopic activation of AHR during early differentiation disrupts the differentiation program via the chromatin remodeling complex NuRD. The activated AHR/NuRD complex altered the expression of differentiation-specific genes that control the first two developmental decisions without affecting the pluripotency program. These findings identify a novel mechanism that allows environmental stimuli to disrupt embryonic development through AHR signaling.
2018-02-26 | PXD006089 | Pride
Project description:The AhR is a ligand activated transcription factor that may be important in normal skin physiology. We compared gene expression profiles between AhR Wt and AhR KO primary mouse keratinocyte cultures. We identified 391 genes that were differentially expressed with a 1.5 fold cutoff and p<.05, and identified the AhR as an important regulator of genes involved in normal epidermal differentiation. AhR Wt primary keratinocyte cultures (n=4) were compared with AhR KO primary keratinocyte cultures (n=3)
2015-07-01 | E-GEOD-62490 | biostudies-arrayexpress