Prednisolone-induced differential gene expression in liver of mice carrying the wild type or a dimerization-defective glucocorticoid receptor
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE21048 | GEO | 2010/05/20
SECONDARY ACCESSION(S): PRJNA126431
REPOSITORIES: GEO
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Project description:Glucocorticoids control expression of a large number of genes after binding to the glucocorticoid receptor (GR). Transcription may be regulated either by binding of the GR dimer to DNA regulatory elements or by protein-protein interactions of GR monomers with other transcription factors. Although the type of regulation for a number of individual target genes is known, the relative contribution of both mechanisms to the regulation of the entire transcriptional program remains elusive. To study the importance of GR dimerization in regulation of gene expression, we performed gene expression profiling in liver of prednisolone-treated wild type (WT) and genetically engineered mice that have lost the ability to form GR-dimers (GRdim). Mice carrying a wild type (WT) glucocorticoid receptor or a dimerization-defective glucocorticoid receptor (GRdim) were treated subcutaneous with vehicle or prednisolone (1mg/kg) and sacrificed 150 minutes later. From the livers of these mice total RNA was extracted, processed and hybridized on Affymetrix microarrays. In total 24 mice (6 vehicle-treated WT mice, 6 prednisolone-treated WT mice, 6 vehicle-treated GRdim mice and 6 prednisolone-treated GRdim mice) were included in the study.
2010-06-08 | E-GEOD-21048 | biostudies-arrayexpress
Project description:Purpose: To investigate the quaternary structures of Rhodopsin-family GPCRs. Method: Analyzed 60 receptors from HEK 293T cells. Results: 1) Most of these receptors are monomers. 2) The phylogenetic distribution of dimers suggests that monomers have an evolutionary advantage due to constraints imposed by dimerization on rates of receptor diversification.
2017-08-10 | GSE102461 | GEO
Project description:A widely regarded model for glucocorticoid receptor (GR) action postulates that dimeric binding to DNA regulates unfavorable metabolic pathways while monomeric receptor binding promotes repressive gene responses related to its anti-inflammatory effects. This model has been built upon the characterization of the GRdim mutant, reported to be incapable of DNA binding and dimerization. Although quantitative live-cell imaging data shows GRdim as mostly dimeric, genomic studies, on the basis of recovery of enriched half-site response elements, suggest monomeric engagement on DNA. Here, we performed genome-wide studies on GRdim and a constitutively monomeric mutant. Our results show that impairing dimerization affects binding to even open chromatin. Also, GRdim does not exclusively bind half-response elements. Our results do not support a physiological role for monomeric GR and are consistent with a common mode of receptor binding via higher order structures that drives both the activating and repressive actions of glucocorticoids.
2021-01-19 | GSE117661 | GEO
Project description:A mutation in the dimerization domain of the mouse glucocorticoid receptor (GR), dim1, has recently been shown to bind DNA and regulate gene expression. To expand these studies we created a stable osteosarcoma (U-2 OS) cell line expressing four mutations in the dimerization domain of the human GR, dim4 (N454D, A458T, R460D, D462C), and used whole human genome microarray analysis to compare differences in gene regulation between vehicle treated (CON) and those treated with the glucocorticoid receptor agonist dexamethasone (DEX) at 100nM concentration for 6 hours.
2011-12-22 | GSE26857 | GEO
Project description:A mutation in the dimerization domain of the mouse glucocorticoid receptor (GR), dim1, has recently been shown to bind DNA and regulate gene expression. To expand these studies we created a stable osteosarcoma (U-2 OS) cell line expressing four mutations in the dimerization domain of the human GR, dim4 (N454D, A458T, R460D, D462C), and used whole human genome microarray analysis to compare differences in gene regulation between vehicle treated (CON) and those treated with the glucocorticoid receptor agonist dexamethasone (DEX) at 100nM concentration for 6 hours. Gene expression in U-2 OS hGRdim4 cells was measured after a 6 hour treatment with 100nM dexamethasone or vehicle (control) and the dexamethsone (dex) treated cells were compared to vehicle treated cells. The experiment was performed in triplicate.
2011-12-22 | E-GEOD-26857 | biostudies-arrayexpress
Project description:The glucocorticoid (GC) receptor (GR) is essential in development and inflammation. Healthy GRdim/dim mice with reduced dimerization propensity due to a point mutation (A465T) at the dimer interface of the GR DNA binding domain (DBD) (here GRD/D) have helped to define GR monomer and dimer functions of GR. Since GRD/D retains residual dimerization capacity, we generated the dimer-nullifying double mutant GRD+L/D+L mice, featuring an additional mutation (I634A) in the ligand binding domain (LBD) of GR. These mice are perinatally lethal, as are GRL/L mice, displaying improper lung and skin formation. We used embryonic fibroblasts, high and low doses of dexamethasone (Dex), nuclear translocation, RNAseq, dimerization assays and ligand binding assays (and Kd values), we suggest that the lethal phenotype is due to insufficient ligand binding. The data suggest cross talk between GR dimerization potential and ligand affinity. We conclude that a mutation as subtle as this I634A, at a position not directly involved in ligand interactions senso stricto, can thus still influence ligand binding and have a lethal outcome.
2021-12-03 | GSE189620 | GEO
Project description:The glucocorticoid (GC) receptor (GR) is essential in development and inflammation. Healthy GRdim/dim mice with reduced dimerization propensity due to a point mutation (A465T) at the dimer interface of the GR DNA binding domain (DBD) (here GRD/D) have helped to define GR monomer and dimer functions of GR. Since GRD/D retains residual dimerization capacity, we generated the dimer-nullifying double mutant GRD+L/D+L mice, featuring an additional mutation (I634A) in the ligand binding domain (LBD) of GR. These mice are perinatally lethal, as are GRL/L mice, displaying improper lung and skin formation. We used embryonic fibroblasts, high and low doses of dexamethasone (Dex), nuclear translocation, RNAseq, dimerization assays and ligand binding assays (and Kd values), we suggest that the lethal phenotype is due to insufficient ligand binding. The data suggest cross talk between GR dimerization potential and ligand affinity. We conclude that a mutation as subtle as this I634A, at a position not directly involved in ligand interactions senso stricto, can thus still influence ligand binding and have a lethal outcome.
2021-11-29 | GSE189356 | GEO
Project description:Background: Glucocorticoids are important pharmaceutical agents in the treatment of acute lymphoblastic leukemia in children. Resistance or sensitivity to glucocorticoids is considered to be of crucial importance for disease prognosis. Prednisolone is a first-line chemotherapeutic agent in the treatment of acute lymphoblastic leukemia. Here, the effects of prednisolone on the resistant CCRF-CEM leukemic cell line were studied. Methods: Prednisolone’s cytotoxic and cell cycle effects were studied with flow cytometry. NF-κB translocation was studied with Western Blotting and differential gene expression was studied with cDNA microarrays. Results: Prednisolone exerted a delayed biphasic effect, necrotic at low doses and apoptotic at higher doses. At low doses, prednisolone exerted a pre-dominant mitogenic effect despite its induction on total cell death, while at higher doses, prednisolone’s mitogenic and cell death effects were counterbalanced. NF-κB was constitutively present in the nucleus. Early gene microarray analysis revealed 40 differentially expressed genes upon 4 hours of prednisolone’s exposure. Notable differences in gene regulation were observed between the lowest and the highest glucocorticoid doses. Prednisolone activated genes related to apoptosis/tumor suppression, cell cycle progression, metabolism and intra-/ extra-cellular signaling pathways. Conclusions: The mitogenic/biphasic effects of prednisolone are of clinical importance in the case of resistant leukemic cells. This approach might lead to the identification of gene candidates for future molecular drug targets in combination therapy with glucocorticoids, along with early markers for glucocorticoid resistance. Elucidation of the mechanisms of GC action may lead to identification of gene targets responsible for GC resistance. Key tools in this process are high-throughput technologies such as microarray-based gene expression analysis. For this purpose, the parental CCRF-CEM cell line was chosen as the system of study for the effects of prednisolone treatment. This is a T-cell leukemia cell line characterized by a mutation (L753F) on one GR gene allele that impairs ligand binding (Thompson and Johnson 2003). It is known that both the DNA and ligand binding domains of the GR are required in order to repress NF-κB transactivation (Wissink, van Heerde et al. 1997). Interestingly, concerning the question whether this mutation would affect GC resistance, it has been reported previously that both the GC-resistant as well as the GC-sensitive CCRF-CEM subclones express heterogeneous populations of the GR (GRwt/GRL753F) (Palmer and Harmon 1991; Powers, Hillmann et al. 1993). The CCRF-CEM cell line has been reported to be resistant to GCs, presumably due to the accumulation of more resistant variants after long periods of prolonged culture (Norman and Thompson 1977). It is possible that these cells are clonally inhomogeneous, as possibly the cells obtained in vivo by patients. Moreover, the large number of the CCRF-CEM subclone studies in the literature makes it difficult to choose an appropriate resistant cell model. In addition, the utilization of an in vitro system for this study offered reproducibility, an opportunity to closely examine intracellular signals and avoid interference from other in vivo-participating systems. Thus, the cell line used for this study was considered to be useful in studying GC action and resistance in leukemic cells. The aim of this work was to determine the cytotoxic, cell cycle phase distribution and early cancer-specific gene expression effects of prednisolone in CCRF-CEM cells, as an in vitro model of ALL resistance to glucocorticoids. The early gene expression profile allowed identification of genes initiating pivotal, early onset regulatory mechanisms activated by GC and excluded ensuing feedback responses and further downstream signals. Samples tested were in the form of a loop-design i.e. control vs. 10nM prednisolone (designated 0vs1) , 10nM prednisolone vs.700uM prednisolone (designated 1vs3) and control vs. 700uM prednisolone (designated 0vs3), the sum of the logarithms of the first two should equal the third. In other words if Rj,i is the ratio of the ith gene in the jth experiment then R0vs1,i+R1vs3,i=R0vs3,i. We tested this using a statistical test. We have applied an intensity-dependent z-score where the sum of the ratios was compared to the ratio of the third experiment. If the difference was significant genes, in a standard deviation threshold of ±1.5 in relative units, were rejected from further analysis (Kerr and Churchill 2001; Kerr and Churchill 2001; Altman and Hua 2006; Kerr and Churchill 2007).
2011-03-22 | E-GEOD-27989 | biostudies-arrayexpress
Project description:Tumor Necrosis Factor (TNF) is an important mediator in numerous inflammatory diseases, e.g. in inflammatory bowel diseases (IBD). In IBD, acute increases in TNF production can lead to disease flares. Glucocorticoids (GCs), which are steroids that bind and activate the glucocorticoid receptor (GR), are able to protect animals and humans against acute TNF-induced inflammatory symptoms. Mice with a poor transcriptional response of GR-dimer-dependent target genes were studied in a model of TNF-induced lethal inflammation. In contrast to the GRwt/wt mice, these GRdim/dim mice displayed a significant increase in TNF sensitivity and a lack of protection by the GC dexamethasone (DEX). Unchallenged GRdim/dim mice had a strong interferon-stimulated gene (ISG) signature, along with STAT1 upregulation and phosphorylation. This ISG signature was gut specific and, based on our studies with antibiotics, depended on the gut microbiota. GR dimers directly bound to short DNA sequences in the STAT1 promoter known as inverted repeat negative GRE (IR-nGRE) elements. Poor control of STAT1 in GRdim/dim mice led to failure to repress ISG genes resulting in excessive necroptosis induction by TNF. Our findings support a critical interplay between gut microbiota, interferons, necroptosis and GR in both the basal response to acute inflammatory challenges and in the pharmacological intervention by GCs.
2018-04-26 | GSE113691 | GEO
Project description:Eukaryotic protein homeostasis (proteostasis) is largely dependent on the action of highly conserved Hsp70 molecular chaperones. Recent evidence indicates that apart from conserved molecular allostery, Hsp70 proteins retained and adapted throughout the evolution the ability to assemble as functionally relevant ATP-bound dimers. Here we have compared the ATP-dependent dimerization of DnaK, human stress-inducible Hsp70, Hsc70 and BiP Hsp70 proteins showing that their dimerization propensities differ with stress-inducible Hsp70 being predominantly dimeric in the presence of ATP. The structural analyses using hydrogen/deuterium exchange mass spectrometry, native electrospray ionization mass spectrometry, chemical cross-linking and small-angle X-ray scattering revealed that stress-inducible Hsp70 assembles in solution as an antiparallel dimer with the intermolecular interface closely resembling the ATP-bound dimer interfaces captured in DnaK and BiP crystal structures. ATP-dependent dimerization of stress-inducible Hsp70 is necessary for its efficient interaction with Hsp40 as shown by experiments with dimerization-deficient mutants. Moreover, dimerization of ATP-bound Hsp70 is required for its participation in high molecular weight protein complexes detected ex vivo supporting its functional role in vivo. As human cytosolic Hsp70 has the ability to interact with tetratricopeptide repeat (TPR) domain containing co-chaperones, we tested the interaction of Hsp70 ATP-dependent dimer with Chip and Tomm34 co-chaperones. While Chip associates with intact Hsp70 dimer to form a larger complex, binding of Tomm34 disrupts Hsp70 dimer and this event plays an important role in Hsp70 activity regulation. In summary, this study provides structural evidence of robust ATP-dependent antiparallel dimerization of human inducible Hsp70 protein and suggests novel role of TPR domain co-chaperones in multichaperone complexes involving Hsp70 ATP-bound dimers.
2018-12-11 | PXD010069 | Pride