Differential effect of glucocorticoids on the activation of monocytes and macrophages
ABSTRACT: The Glucocorticoid receptor (GR/NR3C1) is expressed in almost all immune cells. Glucocorticoids (GCs) are potent regulators of inflammation with effects mainly immunosuppressive. While, GCs have pleiotropic effects on Macrophages exhibiting complex properties with enhancing as well as suppressive effects on inflammatory processes depending on their stage of differentiation and activation, the mechanisms of GCs actions on Monocytes and Macrophages and their contribution to systemic anti-inflammatory effects remain unclear. Previously we have demonstrated that NLRP3 expression is induced by GCs in macrophages differentiated from monocytes-THP-1 but not in monocytes. These findings raise the possibility that the stage of myeloid differentiation and the cellular environment dictates the actions of GR from a pro- or anti-inflammatory perspective. Moreover, our preliminary results using the same cell line THP-1 show that the differentiation process from monocytes to macrophages also is related with the downregulation of GR induced by dex. Overall design: Human Monocyte cell line THP-1 was used for differentiation into macrophages with PMA during 3 hours and a time of recovery of 24 hours. Monocytes-THP-1 and macrophages-derived monocyte-THP-1 were maintained during 24 hours with charcoal medium before the Dex treatment for 6 hours. RNA samples from all treatments groups (Mono-THP-1 Vehicle and Dex and Macro-THP-1 vehicle and Dex) were extracted using QIAshredder and RNeasy Mini kit with DNase treatment. The RNA concentration will be determined by Nanodrop and the quality using BioAnalyzer. We expect to found significant differences in RNA expression between cells (Mono vs Macrophages) and treatment (Vehicle vs Dex).
INSTRUMENT(S): Agilent-014850 Whole Human Genome Microarray 4x44K G4112F (Feature Number version)
Project description:Glucocorticoids (GCs) reduce the expression of many genes induced in inflammatory conditions in vivo or by pro-inflammatory stimuli in vitro acting on the Glucocorticoid receptor (GR/NR3C1). However, GCs have pleiotropic effects on the immune system. Monocytes and macrophages are important cells of the innate immune system, exhibiting complex properties with enhancing as well as suppressive effects on inflammatory processes depending on their stage of activation and differentiation. Macrophages contribute to host defense, tissue remodeling and wound healing The mechanisms of GCs actions on monocytes and macrophages and their contribution to systemic anti-inflammatory effects remain unclear. These effects on activation GCs in monocytes and macrophages were investigated using the human monocytic cell line THP-1 and differentiation protocol PMA. Monocytes-THP1 and macrophages derived-monocytes were exposed for 6 hours to 100 nM of dexamethasone (Dex) and analyzed by microarrays. In macrophages-derived monocytes with respect to monocytes-THP-1, the number of genes differentially regulated was almost twice, among these, genes related with pro-inflammatory pathways, like TNFa, CXCL1 and GZMA. Interestingly, one of the genes differentially regulated (decreased) in macrophages exposed to Dex was the GR itself. If this effect modifies the inflammatory function of macrophages derived-monocyte is a question that will be evaluated through this study. Overall design: For this study, 12 samples were analyzed by NanoString: 2 experimental groups (Monocytes THP-1 and macrophages differentiated from monocytes THP-1; 2x106 cells/well); 2 treatments (vehicle and 100nM Dex); 1 time point (6 h) and x3 replicates. All samples passed nSolver’s initial QA/QC controls. One of the Mac Dex samples (Mac Dex 2) clustered with the Mac Controls and saw no increased expression of FKBP5. It was therefore excluded from further analysis. All remaining replicates were well correlated (R > 0.98).
Project description:Background: Glucocorticoids (GCs) are widely used anti-inflammatory drugs. While useful in clinical practice, patients taking GCs often suffer from skeletal side effects including growth retardation and decreased bone quality in adults. On a physiological level, GCs have been implicated in the regulation of chondrogenesis and osteoblast differentiation, as well as maintaining homeostasis in cartilage and bone. We identified the glucocorticoid receptor (GR) as a potential regulator of chondrocyte hypertrophy in a microarray screen of primary limb bud mesenchyme micromass cultures. Some targets of GC regulation in chondrogenesis are known, but the global effects of pharmacological GC doses on chondrocyte gene expression have not been comprehensively evaluated. Results: This study systematically identifies a spectrum of GC target genes in embryonic growth plate chondrocytes treated with synthetic GR agonist, dexamethasone (DEX), at 6 and 24 hrs. Conventional analysis of this data set and gene set enrichment analysis (GSEA) was performed. Transcripts associated with metabolism were enriched in the DEX condition along with extracellular matrix genes. In contrast, a subset of growth factors and cytokines were negatively correlated with DEX treatment. Comparing DEX-induced gene expression data to developmental changes in gene expression in micromass cultures revealed an additional layer of complexity in which DEX maintains the expression of certain chondrocyte marker genes while inhibiting factors that promote vascularization and ultimately ossification of the cartilaginous template. Conclusions: Together, these results provide insight into the mechanisms and major molecular classes functioning downstream of DEX in primary chondrocytes monolayers. In addition, comparison of our data with microarray studies of DEX treatment in other cell types demonstrated that the majority of DEX effects are tissue-specific. This study provides novel insights into the effects of pharmacological GC on chondrocyte gene transcription and establishes the basis for subsequent functional studies. Experiment Overall Design: Primary chondrocytes isolated from the tibiae, humeri and femurs of 15.5 day old mice are treated with 10EXP-7M DEX or an equal volume of the DMSO vehicle for 24 hrs. Total RNA is isolated after 6 hrs and 24 hrs of treatment. Samples from three independent experiments independent time courses were hybridized to Affymetrix MOE 430 2.0 mouse chips. Experiment Overall Design: Number of time points: 2 (6hr and 24 hr) Experiment Overall Design: Number of treatments: 2 (DEX and the vehicle control) Experiment Overall Design: Number of Samples: 3 replicates per time point per treatment Experiment Overall Design: Affymetrix chip: MOE 430 2.0 Experiment Overall Design: Cell type: Primary chondrocyte Experiment Overall Design: Tissue or origin: Tibiae, humerus, femur Experiment Overall Design: Species E15.5 mice Experiment Overall Design: Samples: Total RNA
Project description:Glucocorticoids (GC) display pleiotropic effects on the immune system. Macrophages are a major target for GC action. Here we show that dexamethasone (DEX), a synthetic GC, decreased viability of naïve bone marrow-derived macrophages (BMDM), involving an apoptotic mechanism. Administration of DEX together with lipopolysaccharide (LPS) protected BMDM against DEX-mediated cell death, suggesting that activated BMDM respond to DEX differently than naïve BMDM. An insight to the molecular basis of LPS actions was provided by a 7 fold increase in mRNA levels of glucocorticoid receptor beta (GRβ), a GR dominant-negative splice variant which inhibits GRα's transcriptional activity. LPS did not inhibit all DEX-mediated effects on BMDM; DEX significantly reduced the percentage of BMDM expressing high levels of the cell surface markers F4/80 and CD11b and led to a decrease in macrophage inflammatory protein 1 alpha (MIP1-α) mRNA and protein levels. These two DEX-mediated effects were not prevented by LPS. Our finding that LPS did not reduce the DEX-induced elevation of glucocorticoid-induced leucine zipper (GILZ), a mediator of GCs anti-inflammatory actions, may provide an underlying mechanism. These findings enable a better understanding of clinical states, such as sepsis, in which macrophages are activated by endotoxins and treatment by GCs is considered.
Project description:Glucocorticoids (GCs) play a central role in modulation of inflammation in various diseases, including respiratory diseases such as sarcoidosis. Surprisingly, the specific anti-inflammatory effects of GCs on different myeloid cells especially in macrophages remain poorly understood. Sarcoidosis is a systemic granulomatous disease of unknown etiology that occurs worldwide and is characterized by granuloma formation in different organs. Alveolar macrophages play a role in sarcoidosis granuloma formation and progressive lung disease. The goal of the present study is to identify the effect of GCs on transcriptomic profiles and the cellular pathways in sarcoidosis alveolar macrophages and their corresponding blood myeloid cells. We determined and compared the whole transcriptional signatures of alveolar macrophages from sarcoidosis patients and blood CD14+ monocytes of the same subjects in response to in vitro treatment with dexamethasone (DEX) via RNA-sequencing. In response to DEX, we identified 2,834 genes that were differentially expressed in AM. Predominant pathways affected were as following: metabolic pathway (FDR = 4.1 × 10-10), lysosome (FDR = 6.3 × 10-9), phagosome (FDR = 3.9 × 10-5). The DEX effect on AMs is associated with metabolic derangements involving glycolysis, oxidative phosphorylation and lipid metabolisms. In contrast, the top impacted pathways in response to DEX treatment in blood CD14+ monocytes were as following; cytokine-cytokine receptor interaction (FDR = 6 × 10-6) and transcriptional misregulation in cancer (FDR = 1 × 10-4). Pathways similarly affected in both cell types were genes involved in lysosomes, cytoskeleton and transcriptional misregulation in cancer. These data suggest that the different effects of DEX on AMs and peripheral blood monocytes are partly dictated by lineage specific transcriptional programs and their physiological functions.
Project description:Lineage commitment and differentiation of mesenchymal stromal cells (MSCs) into osteoblasts in vitro is enhanced by a potent synthetic form of glucocorticoid (GC), dexamethasone (Dex). Paradoxically, when used chronically in patients, GCs exert negative effects on bone, a phenomenon known as glucocorticoid-induced osteoporosis in clinical practice. The mechanism on how GC differentially affects bone precursor cells to become mature osteoblasts during osteogenesis remains elusive. In this study, the dose and temporal regulation of Dex on MSC differentiation into osteoblasts were investigated. We found that continuous Dex treatment led to a net reduction of the maturation potential of differentiating osteoblasts. This phenomenon correlated with a decrease in glucocorticoid receptor (GR) expression, hastened degradation, and impaired sub cellular localization. Similarly, Histone Deacetylase 6 (HDAC6) expression was found to be regulated by Dex, co-localized with GR and this GR-HDAC6 complex occupied the promoter region of the osteoblast late marker osteocalcin (OCN). Combinatorial inhibition of HDAC6 and GR enhanced OCN expression. Together, the cross-talk between the Dex effector molecule GR and the inhibitory molecule HDAC6 provided mechanistic explanation of the bimodal effect of Dex during osteogenic differentiation of MSCs. These findings may provide new directions of research to combat glucocorticoid-induced osteoporosis.
Project description:In the present study, we investigated the importance of histone deacetylase 6 (HDAC6) for glucocorticoid receptor (GR) mediated effects on glucose metabolism, and its potential as a therapeutic target for the prevention of glucocorticoid (GC)-induced diabetes. Dexamethasone (dex)-induced hepatic glucose output and GR translocation were analysed in wildtype (wt) and HDAC6-deficient (HDAC6ko) mice. The effect of the specific HDAC6-inhibitor tubacin was analysed in-vitro. Wt and HDAC6ko mice were subjected to 3 weeks dex treatment before analysis of glucose and insulin tolerance. HDAC6ko mice showed impaired dex-induced hepatic GR translocation. Accordingly, dex induced expression of a large number of hepatic genes was significantly attenuated in mice lacking HDAC6 and by tubacin in-vitro. Glucose output of primary hepatocytes from HDAC6ko mice was diminished. A significant improvement of dex-induced whole-body glucose intolerance as well as insulin resistance in HDAC6ko mice compared to wt littermates was observed. The present study demonstrates that HDAC6 is an essential regulator of hepatic GC stimulated gluconeogenesis and impairment of whole body glucose metabolism through modification of GR nuclear translocation. Selective pharmacological inhibition of HDAC6 may provide a future therapeutic option against the pro-diabetogenic actions of GCs. In this dataset, we include the expression data obtained from isolated RNA of dissected mouse livers using wildtype and HDAC6 deficient animals which were treated over a timespan of 3 weeks with 1mg/kg dexamethasone and vehicle respectively. These data are used to show the hdac6-deficiency mediated attenuation of several dexamethasone induced genes. 12 samples in total were analyzed. 3 samples of different animals of each group (wt vehicle, wt dexamethasone, hdac6ko vehicle and hdac6ko dexamethasone)
Project description:The suppression of activated pro-inflammatory macrophages during immune response has a major impact on the outcome of many inflammatory diseases including sepsis and rheumatoid arthritis. The pro- and anti-inflammatory functions of macrophages have been widely studied, whereas their regulation under immunosuppressive treatments such as glucocorticoid (GC) therapy is less well-understood. GC-mediated glucocorticoid receptor (GR) activation is crucial to mediate anti-inflammatory effects. In addition, the anti-cancer drug roscovitine, that is currently being tested in clinical trials, was recently described to regulate inflammatory processes by inhibiting different Cdks such as cyclin-dependent kinase 5 (Cdk5). Cdk5 was identified as a modulator of inflammatory processes in different immune cells and furthermore described to influence GR gene expression in the brain. Whether roscovitine can enhance the immunosuppressive effects of GCs and if the inhibition of Cdk5 affects GR gene regulatory function in innate immune cells, such as macrophages, has not yet been investigated. Here, we report that roscovitine enhances the immunosuppressive Dexamethasone (Dex) effect on the inducible nitric oxide synthase (iNos) expression, which is essential for immune regulation. Cdk5 deletion in macrophages prevented iNos protein and nitric oxide (NO) generation after a combinatory treatment with inflammatory stimuli and Dex. Cdk5 deletion in macrophages attenuated the GR phosphorylation on serine 211 after Dex treatment alone and in combination with inflammatory stimuli, but interestingly increased the GR-dependent anti-inflammatory target gene dual-specificity phosphatase 1 (Dusp1, Mkp1). Mkp1 phosphatase activity decreases the activation of its direct target p38Mapk, reduced iNos expression and NO production upon inflammatory stimuli and Dex treatment in the absence of Cdk5. Taken together, we identified Cdk5 as a potential novel regulator of NO generation in inflammatory macrophages under GC treatment. Our data suggest that GC treatment in combination with specific Cdk5 inhibtior(s) provides a stronger suppression of inflammation and could thus replace high-dose GC therapy which has severe side effects in the treatment of inflammatory diseases.
Project description:BACKGROUND: Glucocorticoids (GCs) are widely used anti-inflammatory drugs. While useful in clinical practice, patients taking GCs often suffer from skeletal side effects including growth retardation in children and adolescents, and decreased bone quality in adults. On a physiological level, GCs have been implicated in the regulation of chondrogenesis and osteoblast differentiation, as well as maintaining homeostasis in cartilage and bone. We identified the glucocorticoid receptor (GR) as a potential regulator of chondrocyte hypertrophy in a microarray screen of primary limb bud mesenchyme micromass cultures. Some targets of GC regulation in chondrogenesis are known, but the global effects of pharmacological GC doses on chondrocyte gene expression have not been comprehensively evaluated. RESULTS: This study systematically identifies a spectrum of GC target genes in embryonic growth plate chondrocytes treated with a synthetic GR agonist, dexamethasone (DEX), at 6 and 24 hrs. Conventional analysis of this data set and gene set enrichment analysis (GSEA) was performed. Transcripts associated with metabolism were enriched in the DEX condition along with extracellular matrix genes. In contrast, a subset of growth factors and cytokines were negatively correlated with DEX treatment. Comparing DEX-induced gene expression data to developmental changes in gene expression in micromass cultures revealed an additional layer of complexity in which DEX maintains the expression of certain chondrocyte marker genes while inhibiting factors that promote vascularization and ultimately ossification of the cartilaginous template. CONCLUSION: Together, these results provide insight into the mechanisms and major molecular classes functioning downstream of DEX in primary chondrocytes. In addition, comparison of our data with microarray studies of DEX treatment in other cell types demonstrated that the majority of DEX effects are tissue-specific. This study provides novel insights into the effects of pharmacological GC on chondrocyte gene transcription and establishes the foundation for subsequent functional studies.
Project description:The efficacy of glucocorticoids (GCs) in treating a wide range of autoimmune and inflammatory conditions is blemished by severe side effects, including osteoporosis. The chief mechanism leading to GC-induced osteoporosis is inhibition of bone formation, but the role of RUNX2, a master regulator of osteoblast differentiation and bone formation, has not been well studied. We assessed effects of the synthetic GC dexamethasone (dex) on transcription of RUNX2-stimulated genes during the differentiation of mesenchymal pluripotent cells into osteoblasts. Dex inhibited a RUNX2 reporter gene and attenuated locus-dependently RUNX2-driven expression of several endogenous target genes. The anti-RUNX2 activity of dex was not attributable to decreased RUNX2 expression, but rather to physical interaction between RUNX2 and the GC receptor (GR), demonstrated by co-immunoprecipitation assays and co-immunofluorescence imaging. Investigation of the RUNX2/GR interaction may lead to the development of bone-sparing GC treatment modalities for the management of autoimmune and inflammatory diseases.
Project description:The activation of monocytes and macrophages is associated with steroid-resistant (SR) asthma. Interleukin-35 (IL-35) is an important anti-inflammatory cytokine, but its regulatory effects on monocytes in patients with SR asthma is not fully understood. Based on clinical response to oral prednisolone, 34 patients with steroid-sensitive (SS) asthma and 20 patients with SR asthma were enrolled in the present study. Serum IL-35 levels were analyzed using the Luminex 200 platform. Monocytes from patients with asthma were pretreated with IL-35 followed by dexamethasone (DEX) and lipopolysaccharide (LPS), then corticosteroid sensitivity was evaluated according to the half-maximal inhibitory concentration of DEX with respect to LPS-induced IL-6 maximal production in monocytes (DEX-IC50). The percentage of maximal inhibition of IL-6 by DEX was presented as Emax. Phosphorylated-P38 mitogen activated kinase (p-p38 MAPK) and mitogen-activated protein kinase phosphatase-1 (MKP-1) were examined by flow cytometry and reverse transcription-quantitative PCR analysis, respectively. Glucocorticoid receptor (GR) binding to the glucocorticoid response element (GRE) was assessed by chromatin immunoprecipitation. Compared with patients with SS asthma, patients with SR asthma had lower IL-35 expression levels (P<0.05). Correlation analysis results demonstrated that the expression levels of IL-35 showed a weak negative correlation with log DEX-IC50 (r=-0.351; P<0.01) and a moderate positive correlation with Emax value (r=0.4501; P<0.01) in all patients with asthma. Moreover, IL-35 enhanced DEX-suppressed IL-6 production and the DEX-induced upregulation of the MKP-1 mRNA expression level in monocytes from both patient groups (P<0.01). In addition, IL-35 inhibited p-p38 MAPK expression in monocytes, and these effects were mediated via an increase in DEX-induced GR binding to GRE. Therefore, IL-35 may be involved in the corticosteroid enhancing effects in monocytes of patients with SR and SS asthma, suggesting potential benefits of IL-35 supplementation in asthmatics with DEX.