Project description:Comparison of differences in gene expression in white and brown adipose tissues in the presence and absence of glucocorticoid receptor expression.
Project description:Comparison of differences in gene expression in white and brown adipose tissues in the presence and absence of glucocorticoid receptor expression.
Project description:Glucocorticoids (GCs) bind to the glucocorticoid receptor (GR) to regulate diverse biological functions from cell growth to apoptosis. Drugs that mimic their action are the most commonly prescribed therapeutic agents in the world and are currently used for the treatment of many diseases including asthma, autoimmune disorders, and some cancers. However, the mechanisms by which one hormone, via one receptor, modulates such diverse biological functions remain unclear. We hypothesized that epigenetic alteration to the GR may contribute to its signaling diversity, and here we demonstrate that Glycogen Synthase Kinase-3-beta phosphorylates GR on Serine 404 in a glucocorticoid-dependent manner. U-2 OS cells expressing a mutant GR that is incapable of Ser404 phosphorylation have enhanced global transcriptional responses, stronger NF-kappaB transrepression, and enhanced cell death in response to dexamethasone. Conversely, presence of Ser404 phosphorylation on the GR inhibits glucocorticoid-dependent NF-kappaB transrepression and cell death of these osteoblasts. Collectively, our results describe a novel convergence point of the GSK-3-beta pathway with the GR resulting in altered glucocorticoid regulated signaling. Our results also provide a mechanism by which the phosphorylation status of Ser404 in GR can dictate how cells will ultimately respond to GCs. Keywords: Glucocorticoid Receptor; GSK-3-beta; NF-kappaB Transrepression; Phosphorylation
Project description:Analysis of local glucocorticoid receptor occupancy at glucocorticoid-repressed inflammatory enhancers in Beas-2B airway epithelial cells II
Project description:The glucocorticoid receptor (GR) recruits many coregulators via the well characterized AF2 interaction surface in the GR ligand binding domain, but LIM domain coregulator Hic-5 binds to the relatively uncharacterized tau2 activation domain in the hinge region of GR. Requirement of Hic-5 for glucocorticoid-regulated gene expression in U2OS osteosarcoma cells was defined by Hic-5 depletion and global gene expression analysis. Hic-5 depletion had selective and dramatic effects, positive and negative, on both activation and repression of GR target genes. For some hormone-induced genes, Hic-5 facilitated recruitment of the Mediator complex and RNA polymerase II. In contrast, many genes were not regulated by hormone until Hic-5 was depleted. On these genes Hic-5 acted at a very early step of the regulatory process, preventing efficient GR binding on enhancers, chromatin remodeling, and thus preventing glucocorticoid-driven transcriptional regulation. Overall, Hic-5 has selective and diverse roles on GR target genes, functioning as coactivator on some genes and corepressor on others, and either facilitating or opposing the glucocorticoid-driven actions of GR. Hic-5 exhibits multiple mechanisms of action, either regulating GR binding to DNA and chromatin remodeling, or facilitating later steps in transcription complex assembly. We investigate the relationship between GR and Hic5 and identify classes of genes that respond differently when cells are induced with hormone and when Hic5 is knocked down We knock down Hic-5 (TGFB1I1) in U2OS cells using siRNA (siHic5_2) along with nonspecific siRNA (shNS) and assay gene expression changes at 4 different time points of hormone treatment. We also include non-infected control (NI) as a second control at each time point.
Project description:Glucocorticoid receptor (GR) has been recently identified as a candidate for acquired anti-androgen and chemotherapy resistance. In order to identify glucocorticoid receptor (GR) targets and studying stromal GR signaling gene expression profiling was performed in primary prostate cancer associated fibroblasts using different treatments.
Project description:Vascular inflammation is present in many cardiovascular diseases and exogenous glucocorticoids have traditionally been used as a therapy to suppress inflammation. However, recent data has shown that endogenous glucocorticoids, acting through the endothelial glucocorticoid receptor, act as negative regulators of inflammation. Here we performed chromatin immunoprecipitation for the glucocorticoid receptor followed by next-gen sequencing in mouse endothelial cells to investigate how the endothelial glucocorticoid receptor regulates vascular inflammation. We identified a novel role of the Wnt signaling pathway in this setting and show that loss of the endothelial glucocorticoid receptor results in up regulation of Wnt signaling both in vitro and in vivo using our validated mouse model. Further we demonstrate glucocorticoid receptor regulation of a key gene in the Wnt pathway via a novel glucocorticoid response element gleaned from our genomic data. These results suggest a novel role for endothelial Wnt signaling modulation in states of vascular inflammation.