The arylhydrocarbon receptor is a ligand inducible transcription factor. Known to control xenobiotic metabolizing enzymes, it also affects - depending on the cell type - numerous other genes, either directly or indirectly. With respect to the immune system, persistent activation leads to immunosuppression. We asked how the AhR is involved in Langerhans cells. These antigen presenting cells of the skin are responsible for allergies against chemicals (thus xenobiotic metabolism might be relevant) and a recently detected endogenous ligand, FICZ made by UVB radiation from tryptophane, is particularly abundant in the skin.
Langerhans cell maturation and contact hypersensitivity are impaired in aryl hydrocarbon receptor-null mice.
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View SamplesThe transcriptome of murine LC after 24 hours in vivo exposure to a moderate dose of 10 microgram 2,3,7,8-tetrachlorodibenzo-p-dioxin was studied.
Langerhans cell maturation and contact hypersensitivity are impaired in aryl hydrocarbon receptor-null mice.
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View SamplesOver activation of the aryl hydrocarbon receptor (AhR) by TCDD results ampng other phenotypes in severe thymic atrophy accompanied by immunosuppression. The link between thymic atrophy, skewed thymocyte differntiation and immunosuppression is still not fully resolved. This study investigates the TCDD elicted exprssion changes in the ET, cortical thymus epithelial cell line.
Promoter analysis of TCDD-inducible genes in a thymic epithelial cell line indicates the potential for cell-specific transcription factor crosstalk in the AhR response.
Treatment, Time
View SamplesOver-activation of the aryl hydrocarbon receptor by TCDD in mice leads among other phenotypes to a severe thymic atrophy accompanied by immunosuppression. TCDD causes a block in thymocyte maturation and a preferential emigration of immature CD4-CD8- DN thymocytes (recent thymic emigrants) into the periphery. As part of this study gene expression profiles from DN thymocytes and thymic emigrants were generated from TCDD and solvent control mice
Role of the aryl hydrocarbon receptor in thymocyte emigration in vivo.
Specimen part, Treatment
View SamplesGlobal gene expression patterns were determined from microarray results on day 1, 3, 5, 7, 10 and 14 during plantaris muscle hypertrophy induced by synergist ablation in young adult mice (5 months).
Time course of gene expression during mouse skeletal muscle hypertrophy.
Sex, Age, Specimen part, Treatment, Time
View SamplesCD4+ T cells from 8-12 week female mice were isolated from wt and AhR-/- mice 24h after injection of 10g/kg TCDD or solvent control.
Transcriptional signatures of immune cells in aryl hydrocarbon receptor (AHR)-proficient and AHR-deficient mice.
Sex, Treatment
View SamplesEffect of an immunosupressive dose of TCDD, a ligand for the aryl hydrocarbon receptor, on the gene expression profile of fetal DN thymocytes and thymic emigrants
Transcriptional signatures of immune cells in aryl hydrocarbon receptor (AHR)-proficient and AHR-deficient mice.
Specimen part, Treatment
View Samples8-12 week, female C57BL/6 mice were injected with 10 g/kg TCDD or solvent control. CD8+ T cells from spleen were FACS purified and submitted to transcription profiling
Transcriptional signatures of immune cells in aryl hydrocarbon receptor (AHR)-proficient and AHR-deficient mice.
Sex, Treatment
View SamplesEffect of the over activation of the aryl hydrocarbon receptor on gene expression of spleen derived dendritic cells.
Transcriptional signatures of immune cells in aryl hydrocarbon receptor (AHR)-proficient and AHR-deficient mice.
Sex, Treatment
View SamplesTo further understand molecular mechanisms underlying skeletal muscle hypertrophy, expression profiles of translationally and transcriptionally regulated genes were characterized following an acute bout of maximally activated eccentric contractions. Experiments demonstrated that translational mechanisms contribute to acute gene expression changes following high resistance contractions with two candidate mRNAs, basic fibroblast growth factor (bFGF) and elongation factor-1 alpha (EF1alpha), targeted to the heavier polysomal fractions after a bout of contractions. Gene profiling was performed using Affymetrix Rat U34A GeneChips with either total RNA or polysomal RNA at one and six hours following contractions. There were 18 genes that changed expression at one hour and 70 genes that were different (60 genes increased:10 genes decreased)at six hours after contractions. The model from this profiling suggests that following high resistance contractions skeletal muscle shares a common growth profile with proliferating cells exposed to serum. This cluster of genes can be classified as "growth" genes and is commonly associated with progression of the cell cycle. However, a unique aspect was that there was induction of a cluster of tumour suppressor or antigrowth genes. We propose that this cluster of "antigrowth" genes is induced by the stress of contractile activity and may act to maintain skeletal muscle in the differentiated state. From the profiling results, further experiments determined that p53 levels increased in skeletal muscle at 6 h following contractions. This novel finding of p53 induction following exercise also demonstrates the power of expression profiling for identification of novel pathways involved in the response to muscle contraction.
Response of rat muscle to acute resistance exercise defined by transcriptional and translational profiling.
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