1
|
Srivastava S, Nataraj NB, Sekar A, Ghosh S, Bornstein C, Drago-Garcia D, Roth L, Romaniello D, Marrocco I, David E, Gilad Y, Lauriola M, Rotkopf R, Kimchi A, Haga Y, Tsutsumi Y, Mirabeau O, Surdez D, Zinovyev A, Delattre O, Kovar H, Amit I, Yarden Y. ETS Proteins Bind with Glucocorticoid Receptors: Relevance for Treatment of Ewing Sarcoma. Cell Rep 2020; 29:104-117.e4. [PMID: 31577941 PMCID: PMC6899513 DOI: 10.1016/j.celrep.2019.08.088] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Revised: 02/06/2019] [Accepted: 08/27/2019] [Indexed: 11/26/2022] Open
Abstract
The glucocorticoid receptor (GR) acts as a ubiquitous cortisol-dependent transcription factor (TF). To identify co-factors, we used protein-fragment complementation assays and found that GR recognizes FLI1 and additional ETS family proteins, TFs relaying proliferation and/or migration signals. Following steroid-dependent translocation of FLI1 and GR to the nucleus, the FLI1-specific domain (FLS) binds with GR and strongly enhances GR's transcriptional activity. This interaction has functional consequences in Ewing sarcoma (ES), childhood and adolescence bone malignancies driven by fusions between EWSR1 and FLI1. In vitro, GR knockdown inhibited the migration and proliferation of ES cells, and in animal models, antagonizing GR (or lowering cortisol) retarded both tumor growth and metastasis from bone to lung. Taken together, our findings offer mechanistic rationale for repurposing GR-targeting drugs for the treatment of patients with ES.
Collapse
Affiliation(s)
- Swati Srivastava
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
| | | | - Arunachalam Sekar
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Soma Ghosh
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Chamutal Bornstein
- Department of Immunology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Diana Drago-Garcia
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Lee Roth
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Donatella Romaniello
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ilaria Marrocco
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Eyal David
- Department of Immunology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Yuval Gilad
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Mattia Lauriola
- Department of Experimental, Diagnostic and Specialty Medicine (DIMES), University of Bologna, Bologna, Italy
| | - Ron Rotkopf
- Department of Biological Services, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Adi Kimchi
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Yuya Haga
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel; Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan
| | - Yasuo Tsutsumi
- Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, Japan; Global Center for Medical Engineering and Informatics, Osaka University, Japan
| | - Olivier Mirabeau
- PSL Research University, "Genetics and Biology of Cancers" Unit, INSERM U830 and Unité Génétique Somatique (UGS), Institut Curie Centre Hospitalier, Paris, France
| | - Didier Surdez
- PSL Research University, "Genetics and Biology of Cancers" Unit, INSERM U830 and Unité Génétique Somatique (UGS), Institut Curie Centre Hospitalier, Paris, France
| | - Andrei Zinovyev
- Institut Curie, PSL Research University, INSERM U900, Mines ParisTech, Paris, France
| | - Olivier Delattre
- PSL Research University, "Genetics and Biology of Cancers" Unit, INSERM U830 and Unité Génétique Somatique (UGS), Institut Curie Centre Hospitalier, Paris, France
| | - Heinrich Kovar
- Children's Cancer Research Institute Vienna, St. Anna Kinderkrebsforschung and Department of Pediatrics, Medical University Vienna, Vienna, Austria
| | - Ido Amit
- Department of Immunology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Yosef Yarden
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot 76100, Israel.
| |
Collapse
|
2
|
The Interactome of the Glucocorticoid Receptor and Its Influence on the Actions of Glucocorticoids in Combatting Inflammatory and Infectious Diseases. Microbiol Mol Biol Rev 2016; 80:495-522. [PMID: 27169854 DOI: 10.1128/mmbr.00064-15] [Citation(s) in RCA: 123] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Glucocorticoids (GCs) have been widely used for decades as a first-line treatment for inflammatory and autoimmune diseases. However, their use is often hampered by the onset of adverse effects or resistance. GCs mediate their effects via binding to glucocorticoid receptor (GR), a transcription factor belonging to the family of nuclear receptors. An important aspect of GR's actions, including its anti-inflammatory capacity, involves its interactions with various proteins, such as transcription factors, cofactors, and modifying enzymes, which codetermine receptor functionality. In this review, we provide a state-of-the-art overview of the protein-protein interactions (PPIs) of GR that positively or negatively affect its anti-inflammatory properties, along with mechanistic insights, if known. Emphasis is placed on the interactions that affect its anti-inflammatory effects in the presence of inflammatory and microbial diseases.
Collapse
|
3
|
Ma Y, Jia Y, Chen L, Ezeogu L, Yu B, Xu N, Liao DJ. Weaknesses and Pitfalls of Using Mice and Rats in Cancer Chemoprevention Studies. J Cancer 2015; 6:1058-65. [PMID: 26366220 PMCID: PMC4565856 DOI: 10.7150/jca.12519] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 07/19/2015] [Indexed: 12/31/2022] Open
Abstract
Many studies, using different chemical agents, have shown excellent cancer prevention efficacy in mice and rats. However, equivalent tests of cancer prevention in humans require decades of intake of the agents while the rodents' short lifespans cannot give us information of the long-term safety. Therefore, animals with a much longer lifespan should be used to bridge the lifespan gap between the rodents and humans. There are many transgenic mouse models of carcinogenesis available, in which DNA promoters are used to activate transgenes. One promoter may activate the transgene in multiple cell types while different promoters are activated at different ages of the mice. These spatial and temporal aspects of transgenes are often neglected and may be pitfalls or weaknesses in chemoprevention studies. The variation in the copy number of the transgene may widen data variation and requires use of more animals. Models of chemically-induced carcinogenesis do not have these transgene-related defects, but chemical carcinogens usually damage metabolic organs or tissues, thus affecting the metabolism of the chemopreventive agents. Moreover, many genetically edited and some chemically-induced carcinogenesis models produce tumors that exhibit cancerous histology but are not cancers because the tumor cells are still mortal, inducer-dependent, and unable to metastasize, and thus should be used with caution in chemoprevention studies. Lastly, since mice prefer an ambient temperature of 30-32°C, it should be debated whether future mouse studies should be performed at this temperature, but not at 21-23°C that cold-stresses the animals.
Collapse
Affiliation(s)
- Yukui Ma
- 1. Shandong Academy of Pharmaceutical Sciences, Ji'nan, Shandong 250101, P.R. China
| | - Yuping Jia
- 1. Shandong Academy of Pharmaceutical Sciences, Ji'nan, Shandong 250101, P.R. China
| | - Lichan Chen
- 2. Hormel Institute, University of Minnesota, Austin, MN 55912, USA
| | - Lewis Ezeogu
- 2. Hormel Institute, University of Minnesota, Austin, MN 55912, USA
| | - Baofa Yu
- 3. Beijing Baofa Cancer Hospital, Shahe Wangzhuang Gong Ye Yuan, Chang Pin Qu, Beijing 102206, P.R. China
| | - Ningzhi Xu
- 4. Laboratory of Cell and Molecular Biology, Cancer Institute, Chinese Academy of Medical Science, Beijing 100021, P.R. China
| | - D Joshua Liao
- 2. Hormel Institute, University of Minnesota, Austin, MN 55912, USA
| |
Collapse
|
4
|
Dhaouadi N, Li JY, Feugier P, Gustin MP, Dab H, Kacem K, Bricca G, Cerutti C. Computational identification of potential transcriptional regulators of TGF-ß1 in human atherosclerotic arteries. Genomics 2014; 103:357-70. [PMID: 24819318 DOI: 10.1016/j.ygeno.2014.05.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Revised: 03/17/2014] [Accepted: 05/03/2014] [Indexed: 11/17/2022]
Abstract
TGF-ß is protective in atherosclerosis but deleterious in metastatic cancers. Our aim was to determine whether TGF-ß transcriptional regulation is tissue-specific in early atherosclerosis. The computational methods included 5 steps: (i) from microarray data of human atherosclerotic carotid tissue, to identify the 10 best co-expressed genes with TGFB1 (TGFB1 gene cluster), (ii) to choose the 11 proximal promoters, (iii) to predict the TFBS shared by the promoters, (iv) to identify the common TFs co-expressed with the TGFB1 gene cluster, and (v) to compare the common TFs in the early lesions to those identified in advanced atherosclerotic lesions and in various cancers. Our results show that EGR1, SP1 and KLF6 could be responsible for TGFB1 basal expression, KLF6 appearing specific to atherosclerotic lesions. Among the TFs co-expressed with the gene cluster, transcriptional activators (SLC2A4RG, MAZ) and repressors (ZBTB7A, PATZ1, ZNF263) could be involved in the fine-tuning of TGFB1 expression in atherosclerosis.
Collapse
Affiliation(s)
- Nedra Dhaouadi
- EA 4173 Génomique Fonctionnelle de l'Hypertension Artérielle, Université de Lyon, Université Lyon 1, Hôpital Nord-Ouest Villefranche-sur-Saône, 8 avenue Rockefeller, F-69373 Lyon, France; Unité de Physiologie Intégrée, Laboratoire de Pathologies Vasculaires, Université de Carthage, Faculté des Sciences de Bizerte, Bizerte, Tunisia
| | - Jacques-Yuan Li
- EA 4173 Génomique Fonctionnelle de l'Hypertension Artérielle, Université de Lyon, Université Lyon 1, Hôpital Nord-Ouest Villefranche-sur-Saône, 8 avenue Rockefeller, F-69373 Lyon, France
| | - Patrick Feugier
- EA 4173 Génomique Fonctionnelle de l'Hypertension Artérielle, Université de Lyon, Université Lyon 1, Hôpital Nord-Ouest Villefranche-sur-Saône, 8 avenue Rockefeller, F-69373 Lyon, France
| | - Marie-Paule Gustin
- EA 4173 Génomique Fonctionnelle de l'Hypertension Artérielle, Université de Lyon, Université Lyon 1, Hôpital Nord-Ouest Villefranche-sur-Saône, 8 avenue Rockefeller, F-69373 Lyon, France
| | - Houcine Dab
- Unité de Physiologie Intégrée, Laboratoire de Pathologies Vasculaires, Université de Carthage, Faculté des Sciences de Bizerte, Bizerte, Tunisia
| | - Kamel Kacem
- Unité de Physiologie Intégrée, Laboratoire de Pathologies Vasculaires, Université de Carthage, Faculté des Sciences de Bizerte, Bizerte, Tunisia
| | - Giampiero Bricca
- EA 4173 Génomique Fonctionnelle de l'Hypertension Artérielle, Université de Lyon, Université Lyon 1, Hôpital Nord-Ouest Villefranche-sur-Saône, 8 avenue Rockefeller, F-69373 Lyon, France
| | - Catherine Cerutti
- EA 4173 Génomique Fonctionnelle de l'Hypertension Artérielle, Université de Lyon, Université Lyon 1, Hôpital Nord-Ouest Villefranche-sur-Saône, 8 avenue Rockefeller, F-69373 Lyon, France.
| |
Collapse
|
5
|
Astrand C, Belikov S, Wrange O. Histone acetylation characterizes chromatin presetting by NF1 and Oct1 and enhances glucocorticoid receptor binding to the MMTV promoter. Exp Cell Res 2009; 315:2604-15. [PMID: 19463811 DOI: 10.1016/j.yexcr.2009.05.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2009] [Revised: 04/29/2009] [Accepted: 05/15/2009] [Indexed: 10/20/2022]
Abstract
Transcription from the mouse mammary tumor virus (MMTV) promoter is induced by the glucocorticoid receptor (GR). This switch was reconstituted in Xenopus oocytes. Previously, we showed that Nuclear Factor 1 (NF1) and Octamer Transcription Factor 1 (Oct1) bind constitutively to the MMTV promoter and thereby induce translational nucleosome positioning representing an intermediary, i.e. preset, state of nucleosome organization. Here we further characterize this NF1 and Oct1 induced preset chromatin in relation to the inactive and the hormone-activated state. The preset chromatin exhibits increased histone acetylation but does not cause dissociation of histone H1 as oppose to the hormone-activated state. Furthermore, upon hormone induction the preset MMTV chromatin displays an enhanced and prolonged GR binding capacity and transcription during an intrinsic and time-dependent silencing of the injected template. The silencing process correlates with a reduced histone acetylation. However, a histone deacetylase inhibitor, trichostatin A (TSA), does not counteract silencing in spite of its distinct stimulation of GR-DNA binding. The latter indicates the importance of histone acetylation to maintain DNA access for inducible factor binding. We discuss how constitutively bound factors such as NF1 and Oct1 may participate in the maintenance of tissue specificity of hormone responsive genes.
Collapse
Affiliation(s)
- Carolina Astrand
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden.
| | | | | |
Collapse
|
6
|
Clark AR. Anti-inflammatory functions of glucocorticoid-induced genes. Mol Cell Endocrinol 2007; 275:79-97. [PMID: 17561338 DOI: 10.1016/j.mce.2007.04.013] [Citation(s) in RCA: 196] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2007] [Accepted: 04/25/2007] [Indexed: 01/12/2023]
Abstract
There is a broad consensus that glucocorticoids (GCs) exert anti-inflammatory effects largely by inhibiting the function of nuclear factor kappaB (NFkappaB) and consequently the transcription of pro-inflammatory genes. In contrast, side effects are thought to be largely dependent on GC-induced gene expression. Biochemical and genetic evidence suggests that the positive and negative effects of GCs on transcription can be uncoupled from one another. Hence, novel GC-related drugs that mediate inhibition of NFkappaB but do not activate gene expression are predicted to retain therapeutic effects but cause fewer or less severe side effects. Here, we critically re-examine the evidence in favor of the consensus, binary model of GC action and discuss conflicting evidence, which suggests that anti-inflammatory actions of GCs depend on the induction of anti-inflammatory mediators. We propose an alternative model, in which GCs exert anti-inflammatory effects at both transcriptional and post-transcriptional levels, both by activating and inhibiting expression of target genes. The implications of such a model in the search for safer anti-inflammatory drugs are discussed.
Collapse
Affiliation(s)
- Andrew R Clark
- Kennedy Institute of Rheumatology Division, Imperial College London, 1 Aspenlea Road, Hammersmith, London W6 8LH, United Kingdom.
| |
Collapse
|
7
|
Smoak K, Cidlowski JA. Glucocorticoids regulate tristetraprolin synthesis and posttranscriptionally regulate tumor necrosis factor alpha inflammatory signaling. Mol Cell Biol 2006; 26:9126-35. [PMID: 16982682 PMCID: PMC1636823 DOI: 10.1128/mcb.00679-06] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Glucocorticoids are used to treat various inflammatory disorders, but the mechanisms underlying these actions are incompletely understood. The zinc finger protein tristetraprolin (TTP) destabilizes several proinflammatory cytokine mRNAs by binding to AU-rich elements within their 3' untranslated regions, targeting them for degradation. Here we report that glucocorticoids induce the synthesis of TTP mRNA and protein in A549 lung epithelial cells and in rat tissues. Dexamethasone treatment leads to a sustained induction of TTP mRNA expression that is abrogated by RU486. Glucocorticoid induction of TTP mRNA is also blocked by actinomycin D but not by cycloheximide, suggesting a transcriptional mechanism which has been confirmed by transcription run-on experiments. The most widely characterized TTP-regulated gene is the AU-rich tumor necrosis factor alpha (TNF-alpha) gene. Dexamethasone represses TNF-alpha mRNA in A549 cells and decreases luciferase expression of a TNF-alpha 3' untranslated region reporter plasmid in an orientation-dependent manner. Small interfering RNAs to TTP significantly prevent this effect, and a cell line stably expressing a short-hairpin RNA to TTP conclusively establishes that TTP is critical for dexamethasone inhibition of TNF-alpha mRNA expression. These studies provide the molecular evidence for glucocorticoid regulation of human TTP and reflect a novel inductive anti-inflammatory signaling pathway for glucocorticoids that acts via posttranscriptional mechanisms.
Collapse
Affiliation(s)
- Kathleen Smoak
- Department of Health and Human Services, Laboratory of Signal Transduction, National Institute of Environmental Health Services, National Institutes of Health, Building 101, Research Triangle Park, NC 27709, USA
| | | |
Collapse
|
8
|
Nakerakanti SS, Kapanadze B, Yamasaki M, Markiewicz M, Trojanowska M. Fli1 and Ets1 have distinct roles in connective tissue growth factor/CCN2 gene regulation and induction of the profibrotic gene program. J Biol Chem 2006; 281:25259-69. [PMID: 16829517 DOI: 10.1074/jbc.m600466200] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
CCN2 (connective tissue growth factor), an important regulator of angiogenesis, chondrogenesis, and wound healing, is overexpressed in a majority of fibrotic diseases and in various tumors. This study investigated regulation of CCN2 gene expression by Ets family of transcription factors, focusing on two members, Fli1 and Ets1, with deregulated expression during fibrosis and tumorigenesis. We show that Ets1 and Fli1 have opposite effects on CCN2 gene expression. Ets1 functions as an activator of CCN2 transcription, whereas Fli1 acts as a repressor. A functional Ets binding site was mapped at -114 within the CCN2 promoter. This site not only mediates stimulation by Ets factors, including Ets1, Ets2, and GABPalpha/beta, but is also required for the transforming growth factor (TGF)-beta response. The contrasting functions of Ets1 and Fli1 in regulation of the CCN2 gene were confirmed by suppressing their endogenous levels using adenoviral vectors expressing specific small interfering RNAs. Additional experiments using chromatin immunoprecipitation assays have revealed that in fibroblasts both Ets1 and Fli1 occupy the CCN2 promoter. TGF-beta stimulation resulted in displacement of Fli1 from the CCN2 promoter and a transient inhibition of Fli1 synthesis. Moreover, reduction of Fli1 expression resulted in up-regulation of COL1A1 and COL1A2 genes and down-regulation of the MMP1 gene. Thus, inhibition of Fli1 recapitulated some of the key effects of TGF-beta, suggesting that Fli1 suppression is involved in activation of the profibrotic gene program in fibroblasts. On the other hand, activation of the CCN2 gene downstream of Ets1 is consistent with its role in angiogenesis and extracellular matrix remodeling. This study strongly supports a critical role of Fli1 and Ets1 in the pathological extracellular matrix regulation during fibrosis and cancer.
Collapse
Affiliation(s)
- Sashidhar S Nakerakanti
- Division of Rheumatology and Immunology, Medical University of South Carolina, Charleston, South Carolina 29425, USA
| | | | | | | | | |
Collapse
|
9
|
James ER, Fresco VM, Robertson LL. Glucocorticoid-Induced Changes in the Global Gene Expression of Lens Epithelial Cells. J Ocul Pharmacol Ther 2005; 21:11-27. [PMID: 15718824 DOI: 10.1089/jop.2005.21.11] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
AIMS Clinically, steroid use is accompanied by a risk for posterior subcapsular cataracts (PSCs). PSC possibly involves perturbation of lens epithelial cell proliferation and differentiation; however, the underlying mechanism is unknown. In this study, we aimed to characterize changes in gene expression in human lens epithelial cells exposed to glucocorticoid using DNA microarray hybridization. METHODS Human lens epithelial cells (HLE B-3) were treated with dexamethasone (1 microM) for 24 or 48 hours or with vehicle (0.01% dimethylsulfoxide) and the derived cRNA was hybridized to U133A microarrays. Data were processed using the Affymetrix program Micro Array Suite, and ontological analyses were performed using the software dChip, filtering to exclude transcripts up- or down-regulated by less than 2-fold. RESULTS At 24 hours, 57 transcripts were upregulated relative to controls by greater than 2- fold and 50 were downregulated by greater than 2-fold. At 48 hours, 92 transcripts were upregulated and 42 were downregulated. Twenty-two upregulated and 2 downregulated transcripts were shared between the 24-hour and 48-hour data sets. The predominant ontological groupings were: signal transduction, transcription factor activity, cytoskeleton/ECM/adhesion, transport, and cell cycle/development. Alternate ontological interpretations are possible. CONCLUSIONS The data indicate steroid treatment of lens epithelial cells is associated with significant changes in gene expression in several functional categories and these include transcripts related to cell proliferation.
Collapse
Affiliation(s)
- Eric R James
- Department of Ophthalmology, Storm Eye Institute, Medical University of South Carolina, Charleston, SC 29403, USA.
| | | | | |
Collapse
|
10
|
Hansson M, Wikvall K, Babiker A. Regulation of sterol 27-hydroxylase in human monocyte-derived macrophages: up-regulation by transforming growth factor β1. Biochim Biophys Acta Mol Cell Biol Lipids 2005; 1687:44-51. [PMID: 15708352 DOI: 10.1016/j.bbalip.2004.11.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2004] [Revised: 10/04/2004] [Accepted: 11/03/2004] [Indexed: 01/22/2023]
Abstract
Regulatory mechanisms for human CYP27A1 enzyme have not yet been fully investigated. Our approach was to add different hormones and cytokines to cultured human monocyte-derived macrophages, and assess the effects on the CYP27A1 by measuring the production of 27-hydroxylated cholesterol in the media. Of the different hormones and cytokines tested, only transforming growth factor beta1 (TGF-beta1) had a clear effect on CYP27A1. Further experiments showed a significant increase in 27-hydroxylated cholesterol products (27-hydroxycholesterol and 3beta-hydroxy-5-cholestenoic acid). A concomitant increase in CYP27A1 mRNA levels was also seen and this positive effect was confirmed using a human CYP27A1 luciferase reporter gene expressed in HepG2 cells. Experiments with progressive deletion/luciferase reporter gene constructs indicated that a TGF-beta1 responsive sequence might be localized in a region about 400 bp upstream of the CYP27A1 translation start. The possibility is discussed that induction of CYP27A1 by TGF-beta1 may be responsible for some of the anti-atherogenic properties of this cytokine.
Collapse
Affiliation(s)
- Magnus Hansson
- Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska University Hospital at Huddinge, SE-141 86 Stockholm, Sweden
| | | | | |
Collapse
|
11
|
Abstract
Glucocorticoids are among the most widely prescribed anti-inflammatory drugs. They act by binding to the glucocorticoid receptor (GR) that, upon activation, translocates to the nucleus and either stimulates or inhibits gene expression. GR inhibition of many proinflammatory response genes occurs through induction of the synthesis of anti-inflammatory proteins as well as through repression of proinflammatory transcription factors, such as nuclear factor-kappaB (NF-kappaB) or activator protein-1 (AP-1). In this review, we discuss the molecular mechanisms underlying GR inhibition of inflammatory responses, with an emphasis on repression of NF-kappaB and AP-1 and their respective signaling pathways.
Collapse
Affiliation(s)
- Kathleen A Smoak
- Department of Health and Human Services, Laboratory of Signal Transduction, National Institute of Environmental Health Services, National Institutes of Health, Building 101, Research Triangle Park, NC 27709, USA
| | | |
Collapse
|